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  • 101
    Electronic Resource
    Electronic Resource
    Springer
    Psychopharmacology 93 (1987), S. 243-249 
    ISSN: 1432-2072
    Keywords: Vasopressin ; Desglycinamide-vasopressin ; Amphetamine ; Matching to position ; Memory ; Arousal ; Signal detection ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The effects of peripherally injected arginine vasopressin (AVP: 0–25 μg/kg), its desglycinamide analogue (DGAVP: 0–25 μg/kg), which is practically devoid of pressor activity, and d-amphetamine (AMP: 0–1.25 mg/kg) were studied using a delayed (0–32 s) matching to position task (Dunnett 1985). A limited hold for responding (20 s) was in operation. This task enables an accurate assessment of forgetting in rats. AVP reliably improved per cent correct performance, and this effect was substantiated by accuracy indices derived from signal detection theory (TSD). DGAVP, however, was inactive, suggesting that the parent peptide's pressor properties were responsible for its beneficial effects. AMP disrupted performance in a dose-related manner, and was the only substance to alter a TSD bias index (responsivity index, RI), indicating a degree of response repetition at the highest dose. These results are consistent with some earlier reports, and suggest that AVP may enhance memory by peripheral action, while AMP disrupts performance. Closer inspection of the data, however, suggested that the peptide reduced general responsiveness. A new index to measure bias (Sahgal 1987) suggested that AVP-treated subjects restricted their sample and choice responses to one side of the operant chamber, thereby achieving a spuriously high detection rate with few errors of commission (incorrect responses). It is concluded that AVP does not, after all, improve performance: on the contrary it has detrimental effects, and produces errors of omission (failure to respond).
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  • 102
    ISSN: 1432-2072
    Keywords: d-Amphetamine ; Simultaneous discrimination ; Control by S+ and S− ; General transfer ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Rats were trained in a Y-maze on a two-choice simultaneous black-white discrimination with either black or white as S+. Animals were then transferred to one of three discrimination tasks. In task 1 (New S−), a new stimulus, either vertical or horizontal stripes, was substituted for the original S−. In task 2 (New S+), a new stimulus, either vertical or horizontal stripes as in task 1, was substituted for the original S+. In task 3 (New S+/S−) animals were trained on horizontal-vertical discrimination. The pre-trial administration of 1 mg/kg d-amphetamine facilitated the acquisition of the original black-white discrimination with both black as S+ and white as S+. Likewise, the drug improved performance in all three transfer conditions. However, the course of learning in the three transfer tasks was different in the placebo- and amphetamine-treated animals. Amphetamine-treated animals were disrupted more by a change in S+ than by a change in S−, whereas the opposite pattern was evident in the placebo controls. When both discriminative stimuli were changed, placebo animals exhibited pronounced decrement in performance, whereas amphetamine animals exhibited excellent learning. The implications of these findings for the effects of amphetamine on discrimination learning are discussed.
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  • 103
    ISSN: 1432-2072
    Keywords: Trimethyltin ; Hippocampus ; Learning and memory ; Autoshaping ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The organometal neurotoxin trimethyltin (TMT), induces impaired learning and memory for various tasks. However, administration is also associated with other “non-specific” behavioral changes which may be responsible for effects on conditioned behaviors. To determine if TMT treatment causes a specific learning impairment, three experiments were done using variations of a delay of reinforcement autoshaping task in which rats learn to associate the presentation and retraction of a lever with the delivery of a food pellet reinforcer. No significant effects of TMT treatment were found with a short (4 s) delay of reinforcement, indicating that rats were motivated and had the sensorimotor capacity for learning. When the delay was increased to 6 s, 3.0 or 6.0 mg TMT/kg produced dose-related reductions in behaviors directed towards the lever. Performance of a group given 7.5 mg TMT/kg, while still impaired relative to controls, appeared to be better than the performance of groups given lower doses. This paradoxical effect was investigated with a latent inhibition paradigm, in which rats were pre-exposed to the Skinner boxes for several sessions without delivery of food reinforcement. Control rats showed retardation of autoshaping when food reinforcement was subsequently introduced. Rats given 7.5 mg TMT/kg exhibited elevated levels of lever responding during pre-exposure and autoshaping sessions. The results indicate that 7.5 mg TMT/kg produces learning impairments which are confounded by hyperreactivity to the environment and an inability to suppress behavior toward irrelevant stimuli. In contrast, low doses of TMT cause learning impairments which are not confounded by hyperreactivity, and may prove to be useful models for studying specific associational dysfunctions.
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  • 104
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    Psychopharmacology 93 (1987), S. 389-392 
    ISSN: 1432-2072
    Keywords: Microgram doses of diazepam ; Convulsions ; Punishment-induced behavioral suppression ; Mouse ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Cooper (1983, 1985) observed an inhibition of ambulation and fluid intake in rats following diazepam in the microgram dose range. The present study aimed at investigating the effects of microgram doses of this benzodiazepine on i) the threshold doses of either pentylenetetrazole, picrotoxin or bicuculline required to induce seizures in mice and ii) the suppression of lever pressing for food induced by the delivery of one electric footshock every ten presses in rats pretreated or not with isoniazid (64 mg/kg IP). Diazepam 4–32 μg/kg IP) neither reduced seizure threshold doses of either convulsant studied nor did this drug (16–128 μg/kg IP) reliably decrease the number of lever presses under the punishment schedule. The present study provides no further evidence for a dose-related biphasic effect of diazepam which could give new insight into the functioning of benzodiazepine-coupled brain processes.
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  • 105
    ISSN: 1432-2072
    Keywords: Dopamine (DA) ; D-1 DA receptor agonist (SK&F 38393) ; D-2 DA autoreceptor agonist (B-HT 920) ; Combination ; Postsynaptic DA receptor-induced stereotyped behavior ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Postsynaptic dopaminergic behavioural effects of D-2 agonists can be promoted by concomitant D-1 receptor activation. The present experiment explored whether such effects could be elicited by the putative autoreceptor-selective D-2 agonist B-HT 920, when combined with the D-1 agonist SK&F 38393. Except for occasional jerks induced by B-HT 920, neither agonist caused significant dopaminergic stimulation when given separately, whereas combined treatment with SK&F 38393 and B-HT 920 induced clear-cut motor activation — particularly focused stereotyped licking and sniffing — in reserpine/AMT-pretreated rats. Both the D-1 antagonist SCH 23390 and the D-2 antagonist spiperone abolished these effects, while the SK&F/B-HT-induced stimulation was not significantly affected by the alpha2-blocker idazoxan. It appears that classical postsynaptic DA receptor-stimulatory properties of B-HT 920 can indeed be demonstrated, provided that sufficient D-1 receptor tone prevails.
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  • 106
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    European journal of nutrition 26 (1987), S. 43-51 
    ISSN: 1436-6215
    Keywords: Dietary protein ; Vitamin A ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition , Medicine
    Description / Table of Contents: Zusammenfassung Es wurde der Einfluß von Qualität und Quantität von Nahrungsproteinen auf die Verteilung einer einzigen massiven Dosis von Vitamin A in verschiedenen Organen wachsender Wistar-Ratten untersucht. Die Untersuchungen wurden mit Casein- und Bengal-Gram-Diäten mit 20 % und 10 % Proteingehalt und auch mit radioaktiv markiertem Retinylacetat durchgeführt. Die Ergebnisse zeigen, daß die Leberspeicherung sowohl von Vitamin A aus der Nahrung als auch die einer einzigen starken Vitamin-A-Gabe (20 000 I.U.) stark herabgesetzt war bei Ratten, die nach der Bengal-Gram-Diät gefüttert wurden, verglichen mit Ratten, die auf Casein-Diät gesetzt waren. Im Gegensatz zur Leberspeicherung ist das Vitamin-A-Niveau im Plasma in allen Gruppen vergleichbar. Füttern niedriger Protein-Qualität reduzierte die Gewebeverteilung von [3H]-Retinylacetat sowohl bei Kontrollratten als auch bei solchen, denen eine massive Dosis Vitamin A gegeben wurde. Diese Untersuchung läßt vermuten, daß sowohl schlechte Qualität als auch unzureichende Mengen von Nahrungsproteinen nachteilige Einflüsse auf den Vitamin-A-Zustand wachsender Ratten haben.
    Notes: Summary The influence of the quality and the quantity of dietary proteins on the distribution of a single massive dose of vitamin A in various organs of growing Wistar strain rats has been studied by using casein and bengal gram diets at 20 % and 10 % protein levels. The distribution of [3H]-retinyl acetate in various tissues was also investigated in these dietary conditions. The results show that the hepatic storage of dietary as well as a single massive dose (20,000 I.U.) of vitamin A was profoundly decreased in the rats fed on bengal gram diets as compared to those fed on casein diets. Regardless of hepatic stores, the plasma vitamin A levels were comparable in all the groups. Feeding of low quality of protein reduced the tissue distribution of [3H]-retinyl acetate in control as well as rats given a massive dose of vitamin A. This study suggests that both the poor quality and the inadequate quantity of dietary protein are detrimental influences on the vitamin A status of the growing rats.
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  • 107
    ISSN: 1432-2013
    Keywords: Cortical collecting tubule ; Rat ; ADH ; Principal cells ; Intercalated cells ; Barium ; Amiloride ; Ouabain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The mechanism of ion transport across principal cells of rat cortical collecting tubules (CCT) and its regulation by vasopressin (ADH) has been studied in the isolated perfused tubule. To amplify the response to ADH rats were treated with 5 mg I. M. desoxycorticosterone 4–9 days prior to the experiments. Addition of 2·10−10 mol·1−1 ADH increased the transepithelial voltage from −5.1 ±0.7 mV to −16.1±1.4 mV (n=37) and decreased the transepithelial resistance from 51±4 Ω cm2 to 39±2 Ω cm2 (n=33). Optical and functional differentiation of impalements of principal and intercalated cells was made and only data of principal cells are presented. ADH depolarized the apical membrane from 79±1 mV to 66±2 mV (n=26) and decreased the fractional resistance of the apical membrane from 0.76±0.04 to 0.70±0.04 (n=13). These ADH effects were prevented by 10−5 or 10−4 mol·1−1 luminal amiloride which hyperpolarized the apical membrane when added in the presence or absence of ADH. Apical and basolateral membranes were dominated by large K+ conductances and addition of 3 mmol·1−1 barium to bath or lumen perfusates increased transepithelial resistance almost two-fold, whereas luminal amiloride increased the transepithelial resistance only by 26–35%. Ouabain (0.5 mmol·1−1, bath) depolarized the basolateral membrane and decreased its K+ conductance. These effects were prevented by the simultaneous presence of apical amiloride suggesting that the only route of Na+ entry into the principal cells occurred via the amiloride sensitive Na+ conductance. We conclude that ADH stimulates Na+ reabsorption and K+ secretion in the rat CCT primarily by increasing the Na+ conductance in the apical cell membrane.
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  • 108
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    Pflügers Archiv 409 (1987), S. 194-199 
    ISSN: 1432-2013
    Keywords: Sodium transport ; Amiloride ; Colon ; Rat ; Ontogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract To evaluate developmental changes in colonic sodium transport, the sensitivity of the transepithelial potential and short-circuit current to amiloride was investigated. The amiloride-sensitive short-circuit current (I sc Na ), which represents the electrogenic sodium transport through Na+ channels, rose significantly from day 5, reached a peak on day 10, and entirely disappeared after weaning. The maximum rate of electrogenic, amiloride-sensitive sodium transport was 12.0 μEq/cm2 · h. TheI sc Na was suppressed by adrenalectomy and/or premature weaning but not by a mineralocorticoid antagonist, spironolactone. On the contrary, treatments which increase aldosterone levels in vivo (low-sodium diet, furosemide-induced natriuresis, high dietary intake of potassium) stimulated theI sc Na . The effect of adrenalectomy increased during postnatal development. The sensitivity ofI sc Na to aldosterone was highest at the end of the weaning period. High-sodium diet, which causes a decrease in circulating aldosterone, was associated with a partial inhibition ofI sc Na (P〈0.016). These data suggest that the distal colon of neonatal rats can transport sodium via an electrogenic, amiloride-sensitive mechanism and that adrenocortical hormones exert the main regulatory control of this pathway.
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  • 109
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    Research in experimental medicine 187 (1987), S. 87-94 
    ISSN: 1433-8580
    Keywords: Rat ; Shock ; Peritonitis ; E. coli injection ; Blood flow distribution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Cardiac output and its distribution were studied in rats made septic by an i.p. injection of liveE. coli bacteria and in controls given an equivalent amount of saline. The E. coli injection was followed by signs of severe shock in eight of 12 rats. Control animals all survived with only minor changes in cardiac output and peripheral hemodynamics. Blood flow in shocked animals was characterized by a reduction of cardiac output, while myocardial and cerebral flows were not reduced. The intact circulation to the brain and to the heart in the shocked rats was at the expense of kidney, spleen, and skin blood flows.
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  • 110
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    Research in experimental medicine 187 (1987), S. 153-158 
    ISSN: 1433-8580
    Keywords: Degradable starch microspheres ; Hepatic artery ; Rat ; Adenocarcinoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Effects of degradable starch microspheres administered via the hepatic artery were examined in rats in which an adenocarcinoma was transplanted into the liver.3H-uridine or3H-uracil with cold uridine and uracil, respectively, in amounts corresponding to therapeutic doses of these two pyrimidines as fluoro compounds, were administered with or without microspheres. Labeling of the acid-soluble fraction and RNA of tumor, liver, small intestine, spleen, kidney, and bone marrow was examined after 3 and 60 min after injection. When microspheres were added, the specific radioactivity of tumor RNA was significantly higher at both 3 min (P 〈 0.05) and 60 min (P 〈 0.01) in the rats given uridine, and in rats given uracil it was higher at 60 min after injection (P 〈 0.05). There were no such differences in the labeling of the normal tissues. The results indicate that arterial administration of cytostatic drugs, such as 5-fluoropyrimidines, together with degradable starch microspheres might increase the cytotoxic effect on tumors nourished by the artery.
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  • 111
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    Research in experimental medicine 187 (1987), S. 353-358 
    ISSN: 1433-8580
    Keywords: Indoleamines ; Brain ; Rat ; Decarboxylase inhibition ; Portacaval shunt (PCS) ; Protein ingestion ; Encephalopathy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In rats with a portacaval shunt (PCS), the effect on the serotonin metabolism in the brain after oral administration of blood, a mixed amino acid solution (Vamin 14; KabiVitrum, Sweden) or a 10% glucose solution was studied. One week after PCS, the animals were fed with a gastric tube for 8 h and thereafter tested for behavioral abnormalities before decapitation at 12 h. The concentration of 5-hydroxytryptophan (5-HTP), serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) were analyzed chromatographically (HPLC technique with electrochemical detection) in different regions of the brain. Estimation of synthetic rates of 5-hydroxyindoles was facilitated by aromatic aminoacid decarboxylase inhibition (m-hydroxybenzylhydrazine; NSD 1015). The brain concentrations of 5-HTP, 5-HT, and 5-HIAA were increased in all shunted rats as compared with sham-operated animals. Whether animals received blood, glucose, or aminoacid solution made no differences in the brain concentrations of 5-HTP and 5-HT. Concentrations of 5-HIAA were lower in those animals receiving blood as compared with the other shunted groups. No reproducible differences in the behavior of the animals were observed. These results suggest that massive blood administration 1 week after PCS in rats has no influence on the rate of brain indole synthesis. While alterations in serotonin metabolism may play a role in some forms of encephalopathy, this study implies that the behavioral and neurologic disorders which follow gastrointestinal tract hemorrhage in patients with liver failure may have other etiologies.
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  • 112
    ISSN: 1433-8580
    Keywords: Zona glomerulosa ; Dopaminergic system ; Aldosterone ; Rat ; Stereology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of metoclopramide (MTC) and bromocriptine (BRC) (two drugs which act as antagonist and agonist of DOPA-receptors, respectively) on the zona glomerulosa of dexamethasone/ACTH-treated rats were investigated by coupled biochemical and morphometric techniques. Shortterm (1-h) MTC administration significantly increased the plasma concentration of aldosterone, while long-term (7-day) MTC administration, as well as short- and long-term treatment with BRC did not cause any apparent change. Long-term MTC administration was found to significantly potentiate both the rise in the plasma level of aldosterone and the hypertrophy of the zona glomerulosa and its parenchymal cells induced by a prolonged treatment with angiotensin II (AII), but not those evoked by a chronic sodium deprivation alone or combined with AII infusion. Long-term BRC administration notably counteracted the effects of sodium restriction (coupled or not with AII infusion), but not those induced by the administration of AII alone. Long-term MTC administration partially reversed both the lowering of the plasma concentration of aldosterone and the atrophy of the zona glomerulosa and its parenchymal cells caused by a prolonged sodium-loading (combined or not with captopril infusion), but not those produced by the administration of captopril alone. On the other hand, long-term BRC treatment induced a further significant reduction in the blood level of aldosterone and the volume of zona glomerulosa and its cells only in captopriltreated animals. These findings are consistent with the view that the dopaminergic system exerts a maximal tonic inhibitory effect not only on the secretory activity, but also on the growth and steroidogenic capacity of the rat zona glomerulosa. Furthermore, they suggest that the activity of the dopaminergic system is in turn controlled by the sodium balance, being almost completely suppressed by a prolonged sodium deprivation.
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  • 113
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    Urological research 15 (1987), S. 303-306 
    ISSN: 1434-0879
    Keywords: Testicular torsion ; Rat ; Hemodynamics ; Hemorrhagic infarction ; Radiolabelled microspheres
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Experimental testicular torsion must be used for certain studies of clinical relevance, but most experimental models either do not provide hemodynamic alteration comparable to the clinical situation or cannot guarantee reproducibility. Using a rat model arterial perfusion and hemorrhagic infarction were correlated to the degree of both intra- and extravaginal testicular torsion. Arterial inflow was measured sequentially with radiolabelled microspheres, hemorrhagic infarction was judged by the increase of testicular weight. Maximal hemorrhagic infarction and reproducible values were found when the spermatic cord was twisted togehter with the tunica vaginalis for 360°–540°.
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  • 114
    ISSN: 1433-8580
    Keywords: Diet ; Ethanol ; Pancreas ; Proteolytic enzymes ; Protease inhibitors ; Liver ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effects of dietary composition in combination with chronic ethanol ingestion on pancreatic proteolytic-antiproteolytic systems were studied by submitting 192 male Wistar rats to a 12-week dietary period. The rats were fed with a standard (S), fat-rich (F), protein-rich (P), or carbohydrate-rich (C) diet after randomized division into four groups. Half of the animals in each dietary group received water and the other half a mixture of 15% (v/v) ethanol and water as their drinking solution. The C-diet caused a significant increase of BAPNA hydrolysis, which was even more pronounced in rats receiving ethanol. Casein hydrolysis was increased significantly by the C-diet, but ethanol did not have any significant effect on this. Hydrolysis of ATEE was decreased significantly by the P- and C-diets, and ethanol in combination with the S- and F-diets decreased hydrolysis of ATEE in comparison with the corresponding water-receiving groups. The trypsin-inhibiting capacity of the pancreatic tissue was significantly increased in the group receiving C- and F-diets as compared to the S-diet-receiving group of animals. It seems that the composition of the consumed diet in combination with chronic ethanol ingestion may play a role in regulating the pancreatic proteolytic-antiproteolytic system. However, these changes were not parallel. The trypsin-inhibiting capacity of pancreatic tissue was also affected by the quality of the diet.
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  • 115
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    Research in experimental medicine 187 (1987), S. 119-130 
    ISSN: 1433-8580
    Keywords: Indoleamines ; Catecholamines ; Brain ; Rat ; Encephalopathy ; Dearterialisation ; Liver ischaemia ; Decarboxylase inhibition ; Porta caval shunt (PCS)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Subtotal or total liver ischaemia was induced in the rat by dividing the hepatic artery (Expt. I) or by total dearterialisation of the liver (Expt. II) 2 days after porta-caval shunt (PCS). The animals received i.v. a 10% glucose infusion for 5 h after the last operation and were killed by decapitation. At the end of the experiment all animals with liver ischaemia were in Grade III coma. In different regions of the CNS 5-hydroxytryptophan (5-HTP), 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA), were analysed by HPLC-technique with electrochemical detection, while dihydroxyphenylalanine (DOPA), dopamine (DA) and norepinephrine (NE) were analysed with a radio enzymatic method after blocking the decarboxylation of 5-HTP to 5-HT and DOPA to DA by inhibition of the aromatic amino acid decarboxylase enzyme with m-hydroxybenzylhydrazine (NSD 1015) in order to estimate the synthesis rate of 5-hydroxyindoles and catecholamines. In Expt. I concentrations of 5-HTP in animals with PCS were increased as compared to sham operation. In animals with liver ischaemia, 5-HTP concentrations were increased as compared to sham operation but similar to those in animals with PCS alone. These results suggest that ligation of the hepatic artery for 5 h in PCS animals does not further accelerate the rate of brain indole synthesis. In Expt. II, the 5-HTP concentrations were increased in PCS animals as compared to sham operation. Animals with total liver dearterialisation exhibited decreased 5-HTP levels as compared to PCS, suggesting a decreased brain indole synthesis after severe liver ischaemia. In Expt. II, CNS concentrations of DOPA following PCS were unaltered as compared with sham-operated animals. In animals with total liver dearterialisation, DOPA levels were increased, suggesting an augmented catecholamine synthesis. The NE levels were lower than in PCS and in shamoperated animals.
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  • 116
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    Research in experimental medicine 187 (1987), S. 33-41 
    ISSN: 1433-8580
    Keywords: Diet ; Ethanol ; Acute pancreatitis ; Histology ; Nutritional factors ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The correlation between histological findings and mortality was studied in rat experimental acute pancreatitis (AP) modified by different diets and chronic ethanol consumption. Male Wistar rats (n = 192) were divided into eight groups and they were fed either a mixture of water and 15% (v/v) ethanol or tap water combined with standard or special diets for 12 weeks. The animals were followed up for 24 h after induction of AP, and the lowest mortalities were observed in the groups receiving water and standard (S) or carbohydrate-rich (C) diets and the highest in the groups receiving water and protein-(P) or fat-rich (F) diets. In the groups receiving S- or F-diets and ethanol the mortality was significantly increased. The animals were relaparotomized after 24 h of follow-up time. Histological specimens were taken from the surviving rats and evaluated on an arbitrary scale. Histologically, AP was the most severe in the group receiving the C-diet and ethanol, but in this group mortality did not differ significantly from the S-diet and water receiving group. The lack of correlation between the mortality and histological findings suggests nutritional factors to be important for the survival of the animals in experimental AP. It also stresses the assessment of the severity of experimental AP to be based on the all available parameters — not only on the basis of histological findings.
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  • 117
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    European journal of applied physiology 56 (1987), S. 127-131 
    ISSN: 1439-6327
    Keywords: Diaphragm ; Capillary supply ; Fiber type composition ; Endurance training ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Muscle fiber type composition and capillary supply in rat diaphragm were investigated after 14 weeks of endurance training: body weight and muscle fiber area were significantly decreased, the muscle fiber type composition, capillary to fiber ratio and number of capillaries around each fiber type were unchanged, and the capillary density and number of capillaries around each fiber relative to fiber type areas were significantly increased. These small fiber areas and increased capillary supplies in the trained rats would facilitate oxygen transport to all parts of the muscle fiber during exercise. It is concluded that the changes observed in the trained rat diaphragm appear to enhance the capacity for oxidative metabolism.
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  • 118
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    Cell & tissue research 247 (1987), S. 241-247 
    ISSN: 1432-0878
    Keywords: Somatomedin C ; Insulin-like growth factor I (IGF-I) ; Axoplasmic transport ; Sciatic nerve ; Schwann cell ; Trophic influence ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Somatomedin C (Sm-C; insulin-like growth factor I; IGF-I) is a polypeptide (Mr 7649), often dependent on growth hormone (GH), with trophic effects on several different tissues. Monospecific IGF-I antisera were used to investigate its localization in the sciatic nerve and corresponding nerve cells, as well as its possible axoplasmic transport in the adult rat. IGF-I-like immunoreactivity was demonstrated in anterior horn motor nerve cells in the spinal cord and in spinal- and autonomic ganglion nerve cells. Faint IGF-I immunoreactivity was under normal conditions observed in axons of the sciatic nerve and in the Schwann cells. Using crush technique, accumulation of IGF-I immunoreactivity was seen in dilated axons within 2 h, both proximal and distal to the crush. However, only a small fraction of the anterogradely transported IGF-I immunoreactive material could be demonstrated to be transported in retrograde direction. Colchicine injected proximal to a crush prevented accumulation of IGF-I immunoreactivity proximal to the crush, but not distal to it. IGF-I-immunoreactive material is synthesized in the cell bodies of peripheral sensory and motor nerve cells. It is transported at rapid rates in the axoplasm of the sciatic nerve of adult rats both in anterograde and retrograde directions. We propose that axonally transported IGF-I may be released and exert trophic influence on innervated cells, tissues and organs.
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  • 119
    ISSN: 1432-0878
    Keywords: CGRP ; Chromaffin cells ; Nerve fibers ; Adrenal gland ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present immunohistochemical study reveals that a small number of chromaffin cells in the rat adrenal medulla exhibit CGRP-like immunoreactivity. All CGRP-immunoreactive cells were found to be chromaffin cells without noradrenaline fluorescence; from combined immunohistochemistry and fluorescence histochemistry we suggest that these are adrenaline cells. In addition, all CGRP-immunoreactive cells simultaneously exhibited NPY-like immunoreactivity. CGRP-chromaffin cells were characterized by abundant chromaffin granules with round cores in which the immunoreactive material was densely localized. These findings suggest the co-existence of CGRP, NPY and adrenaline within the chromaffin granules in a substantial number of chromaffin cells. Thicker and thinner nerve bundles, which included CGRP-immunoreactive nerve fibers, with or without varicosities, penetrated the adrenal capsule. Most of them passed through the cortex and entered the medulla directly, whereas others were distributed in subcapsular regions and among the cortical cells of the zona glomerulosa. Here the CGRP-fibers were in close contact with cortical cells. A few of the fibers supplying the cortex extended further into the medulla. The CGRP-immunoreactive fibers in the medulla were traced among and within small clusters of chromaffin cells and around ganglion cells. The CGRP-fibers were directly apposed to both CGRP-positive and negative chromaffin cells, as well as to ganglion cells. Immunoreactive fibers, which could not be found close to blood vessels, were characterized by the presence of numerous small clear vesicles mixed with a few large granular vesicles. The immunoreactive material was localized in the large granular vesicles and also in the axoplasm. Since no ganglion cells with CGRP-like immunoreactivity were found in the adrenal gland, the CGRP-fibers are regarded as extrinsic in origin. In double-immunofluorescence staining for CGRP and SP, all the SP-immunoreactive fibers corresponded to CGRP-immunoreactive ones in the adrenal gland. This suggests that CGRP-positive fibers in the adrenal gland may be derived from the spinal ganglia, as has been demonstrated with regard to the SP-nerve fibers.
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  • 120
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Caerulein ; DNA synthesis ; Mitotic activity ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Previous studies from our laboratory indicate that the adaptive response of the exocrine pancreas of the rat to prolonged stimulation with optimal doses of caerulein (0.25 μg × kg-1 × h-1) follows a characteristic time course in which each step in the secretory pathway is activated. The immediate response is the depletion of zymogen-granule stores followed by coordinate and anticoordinate changes in individual rates of (pro-)enzyme synthesis after a lag period of 2 h. The sum of such changes leads to an increase in total rate of protein synthesis by 3 h which is combined with acceleration of intracellular transport packaging and granule discharge. In the present study the time course of DNA synthesis and the labeling index of five populations of pancreatic cells have been analyzed after caerulein stimulation for periods ranging from 6 to 72 h, using in vivo labeling with 1 μCi/g 3H-thymidine 1 h prior to sacrifice of the animals. DNA synthesis did not change during the initial 18 h in spite of persistent stimulation indicated by a 80% reduction of enzyme content. Following this lag period a sharp rise in DNA synthesis 20- to 25-fold above control levels was observed, which decreased by 48 h to reach control levels by 72 h. Increase in DNA synthesis was most pronounced in animals with lowest enzyme content in the pancreas. From the five cell populations studied by autoradiography interlobular duct cells and islet cells had no significant increase in labeling index at any time of stimulation. Acinar cells, intralobular duct cells and interstitial cells showed a marked increase in labeling index after a latent period of 18 h with peak values at 36 h 30 to 50 times higher in intralobular duct and acinar cells, respectively, and 4 times higher in interstitial cells. The increased labeling indices in all three cell populations reverted to lower values at 48 h and reached control values by 72 h. The data indicate a phasic and limited growth response of the rat exocrine pancreas to persistent stimulation with acinar cells as the major contributing cell population.
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  • 121
    ISSN: 1432-0878
    Keywords: Dorsal root ganglia ; Neuropeptides ; Coexistence ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By use of the indirect immunofluorescence technique the distribution of calcitonin gene-related peptide (CGRP)-like immunoreactivity (LI) has been analyzed in cervical and lumbar dorsal root ganglia of untreated and colchicine-treated rats. In addition, lumbar ganglia were examined 2 weeks after transection of the sciatic nerve. The occurrence of CGRP-positive cells in relation to ganglion cells containing substance P-, somatostatin-, galanin-, cholecystokinin (CCK)-, and vasoactive intestinal polypeptide (VIP)/peptide histidine isoleucin (PHI)-LI has been evaluated on consecutive sections as well as using elution-restaining and double-staining techniques. CGRP-LI was observed in many ganglion cells of all sizes ranging in diameter from 15 μm to 65 μm. Thus, this peptide occurs also in the large primary sensory neurons. In contrast to the sensory peptides described to date, CGRP-positive cells constituted up to 50% of all and 70% of the medium-sized neurons, thus being the most frequently occurring peptide in sensory neurons so far encountered. Subpulations of CGRP-positive neurons were shown to contain substance P-, somatostatin-, or galanin-LI and some CGRP-positive neurons contained both substance P- and galanin-LI. In fact, most substance P-, somatostatin- and galanin-positive cell bodies were CGRP-immunoreactive. The coexistence analysis further revealed that galanin and substance P often coexisted and that some cells contained both substance P- and somatostatin-LI, whereas no coexistence between galanin and somatostatin has as yet been seen. VIP/PHI-LI was only shown in a few cells in untreated or colchicine-treated rats. However, after transcetion of the sciatic nerve numerous VIP/PHI-positive cells were observed, some of which also contained CGRP-LI. The present results indicate that a CGRP-like peptide is present in a wide range of primary sensory neurons probably not related to specific sensory modalities. Often this peptide coexists with other biologically active peptides. Taken together these findings suggest that CGRP may have a generalized function.
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  • 122
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    Cell & tissue research 247 (1987), S. 441-444 
    ISSN: 1432-0878
    Keywords: Growth hormone-releasing factor (GRF) ; Neuropeptide immunocytochemistry ; Trigeminal ganglion ; Spinal ganglion ; Development, ontogenetic ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Growth hormone-releasing factor (GRF)-like immunoreactivity has been demonstrated in the trigeminal and spinal ganglia of fetal, young and adult rats by use of peroxidase-antiperoxidase immunohistochemistry. GRF-like-immunoreactive cells first appear during the second half of embryonic life, as early as day 17. In untreated animals the GRF-immunoreactive elements form approximately 1% of all ganglion cells in the trigeminal and spinal ganglia; their numbers do not change significantly during development. The granular immunoreaction product is confined to perikarya, especially to the perinuclear region. Nerve fibers displaying GRF-like immunoreactivity were found neither in the ganglia, nor in the corresponding central and peripheral areas of termination. The possible role of GRF in sensory ganglia is discussed.
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  • 123
    ISSN: 1432-0878
    Keywords: Goblet cells ; Small intestine ; Tight junctions ; Peroxidase ; Cholinergic drugs ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Crypt, but not villus, goblet cells in the ileum accelerate their secretion of mucus within 5 min following cholinergic stimulation. This study was done to determine whether the macromolecular permeability and structure of occluding junctions in the ileum are altered during accelerated secretion. Rats were injected intravenously with horseradish peroxidase followed by carbachol (250 μg/kg, subcutaneous) and the intestinal mucosa was fixed 3–12 min later. In control mucosa (saline-injected), peroxidase filled lateral intercellular spaces up to the occluding junctions of both crypt and villus epithelium, but did not enter occluding junctions or pass into the lumen. In 3 of 8 carbachol-stimulated rats, peroxidase was present within occluding junctions in crypt epithelium and in the crypt lumen, although all intermembrane junctional fusion sites appeared intact. Villus epithelial occluding junctions, in contrast, continued to exclude peroxidase. In freeze-fracture replicas of crypt cells prepared after carbachol stimulation, we detected no structural changes in strand networks of occluding junctions that could account for increased paracellular permeability.
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  • 124
    ISSN: 1432-0878
    Keywords: Cerebral aqueduct ; Ependyma ; Cystic ependymal cells ; Ectopic ependymal cells ; Ependymal ridge ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The wall of the cerebral aqueduct was examined in 20 male rats at the light- and electron-microscopic levels. Disorder in ciliary orientation was occasionally seen in ordinary ependymal cells. Ependymal cells possessing intracellular cysts of 5 to 30 urn in diameter were observed within and beneath the aqueductal ependyma in all animals examined. Light-microscopic reconstruction from serial, 10-μm thick frontal sections revealed an extensive distribution of cystic ependymal cells (CECs), especially along the ependymal ridges in the rostral half of the aqueduct, and along the dorsal region of the aqueductal lining in the caudal half. Both cystic and surface membranes of CECs bore microvilli and cilia. Ectopic ependymal cells (EECs) characterized by densely packed microvilli, well-developed intermediate junctions and cilia, but without cysts, were situated in the subependymal region adjacent to a CEC or another EEC. The ependymal ridges were long, narrow and sporadically stratified ependymal linings extending rostrocaudally and bilaterally along the aqueductal surface. Tanycyte-like cells filled the surface region of the ridge, and CECs and EECs were frequently seen in the core. Intraventricularly injected microperoxidase was detected among densely packed microvilli but not in the cystic lumina of CECs, indicating that EECs and CECs are distinct entities.
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  • 125
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    Cell & tissue research 247 (1987), S. 565-572 
    ISSN: 1432-0878
    Keywords: Synapses ; Perforated synapses ; Synaptic plasticity ; Serial section reconstructions ; Synaptic curvature ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology of perforated synapses in the molecular layer of rat parietal cortex has been studied in 28-day-old animals. Of the perforated synapses analyzed, 92% were axospinous and of these all had asymmetrical contacts. A spinule was present in 20% of them, and 63% had a negative curvature (concave with respect to the presynaptic terminal) overall. Up to 95% of perforated synapses had one or more negatively-curved segments. The perforated synapses studied were characterized by postsynaptic densities (PSD) with a mean length of 581 nm, compared with 233 nm for non-perforated synapses. A study of over 100 serially sectioned synapses demonstrated that, in perforated synapses, the PSD and perforations often had a highly irregular shape and arrangement, the site of the perforation frequently projected into the presynaptic terminal, and coated evaginations of membrane, or coated vesicles, were sometimes found at the site of a perforation or towards the periphery of perforated PSDs. Preliminary reconstructions of perforated synapses suggest that, for descriptive purposes, three types can be recognized. Criteria are formulated for determining, on the basis of a study of single sections, which non-perforated profiles belong to perforated synapses.
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  • 126
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    Cell & tissue research 248 (1987), S. 393-398 
    ISSN: 1432-0878
    Keywords: Adrenaline ; Phenylethanolamine-N-methyl transferase ; Immunocytochemistry ; Electron microscopy ; Central nervous system ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of adrenergic axon terminals was examined in the paraventricular nucleus of the thalamus (PNT) and in the hypothalamic arcuate nucleus-median eminence (ARC-ME) complex by use of phenylethanolamine-N-methyl transferase (PNMT) immunocytochemistry. In the PNT, immunoreactive terminals formed a dense and well-circumscribed plexus. In the ARC, labeled varicosities were less numerous and more evenly distributed. In the ME, they were scarce and confined to the inner zone. In all these areas, the diameter of immunoreactive varicosities ranged between 0.2 and 1.3 μm; in the ME and in the transitional zone between the ARC and the ME, a population of larger boutons (〉2 μm) was also visible. All immunoreactive varicosities exhibited densely packed small, clear vesicles associated with a few large granular vesicles. In the PNT and the ARC, but not in the ME, they formed synaptic contacts with dendritic elements and were occasionally apposed to neuronal cell bodies. These axo-somatic appositions showed no junctional specializations. In the ME and transitional zone, immunoreactive terminals were frequently juxtaposed to, and occasionally established differentiated synaptic contacts with, tanycytes. These data support a transmitter role for adrenaline in the diencephalon and suggest that adrenaline plays a role in hypothalamo-hypophysiotropic regulation through interactions with neural and glial elements.
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  • 127
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    Cell & tissue research 248 (1987), S. 399-407 
    ISSN: 1432-0878
    Keywords: Synapses ; Perforated synapses ; Synaptic plasticity ; Synaptic density ; Morphometry ; Serial sections ; Section thickness ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The numerical density and frequency of perforated synapses in the molecular layer of rat parietal cortex have been determined using 4 procedures in an attempt to overcome problems associated with the size and complex three-dimensional shape of perforated synapses. The following procedures were compared: A, single-section analysis; B, adjacent-section analysis; C, semi-serial-section analysis; and D, complete serial-section analysis. All procedures made use of an unbiased counting rule. Estimates of the numerical density of perforated synapses ranged from 0.06 to 0.27×109 mm-3, and that of all synapses (non-perforated and perforated) from 1.88 to 2.50×109 mm-3. The frequency of perforated synapses varied from 4.5 to 18.0%. Procedures B (adjacent-section analysis) and D (complete serial-section analysis), neither of which utilize assumptions regarding the shape of synapses, produced comparable results (numerical density of perforated synapses 0.19–0.27×109 mm-3, and of all synapses 2.24–2.45×109 mm-3; frequency of perforated synapses 8.6–10.9%). The frequency of perforated synapses appeared to be underestimated by procedure A (single section analysis; 4.5%) and overestimated by C (semi-serial section analysis; 18%). It is concluded that adjacent-section analysis is the most efficient and effective procedure for determining the numerical density and frequency of complex particles, such as perforated synapses. There is, however, no significant difference in the performance of this procedure compared with that of single-section analysis, for determining the numerical density of synapses in general. Nevertheless, inherent problems of bias within the single-section procedure make the adjacent section method the procedure of choice.
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  • 128
    ISSN: 1432-0878
    Keywords: Liver ; LDL-gold conjugates ; Albumin-gold conjugates ; Endocytosis ; B, E receptor ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To elucidate the participation of fetal rat liver cells in the receptor-mediated internalization of low-density lipoproteins (LDL), rat fetuses were injected with either LDL-gold or albumin-gold conjugates. The degree of binding and uptake of LDL-gold and albumin-gold by parenchymal and sinusoidal cells of the fetal rat liver differs markedly. Endothelial cells exhibit low LDL-gold uptake. In contrast, parenchymal cells internalize LDL-gold more actively (45 ± 8 LDL conjugates/100 μm2 cytoplasm within 60 min). Kupffer cells exceed this value by a factor of 20. The uptake of albumin-gold by endothelial and Kupffer cells is high, whereas it is extremely low in parenchymal cells. Estradiol pretreatment causes a significant doubling (p〈0.05) of the LDL-gold particle density/100 μm2 cytoplasm both in parenchymal and Kupffer cells, whereas estradiol has no effect on the albumin uptake. The results strongly indicate that LDL uptake by parenchymal and Kupffer cells in the fetal rat liver is mediated by estrogen-inducible receptors, which may correspond to B, E receptors in the adult liver.
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  • 129
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    Cell & tissue research 248 (1987), S. 103-110 
    ISSN: 1432-0878
    Keywords: Secretory ameloblast ; Ca++-ATPase ; Na+-K+-ATPase ; Ultracytochemistry ; Calmodulin blocker, trifluoperazine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of the calmodulin blocker, trifluoperazine (TEP), on membrane-bound Ca++ -ATPase, Na+ -K+ -ATPase (EC 3.6.1.3.) and the ultrastructure of the enamel organ were investigated in the lower incisors of normal and TFP-injected rats. The rats, of about 100 g body weight, were given either 0.2 ml physiological saline or 100 μg TFP dissolved in 0.2 ml physiological saline through a jugular vein and fixed by transcardiac perfusion with a formaldehyde-glutaraldehyde mixture at 1 and 2 h after TFP administration. Non-decalcified sections of the enamel organ less than 50 μm in thickness, prepared from dissected lower incisors, were processed for the ultracytochemical demonstration of Ca++-ATPase and Na+-K+ -ATPase by the one-step lead method at alkaline pH. In control saline-injected animals the most intense enzymatic reaction of Ca++-ATPase was demonstrated along the plasma membranes of the entire cell surfaces of secretory ameloblasts. Moderate enzymatic reaction was also observed in the plasma membranes of the cells of stratum intermedium and papillary layer. Reaction precipitates of Na+-K+-ATPase activity were localized clearly along the plasma membranes of only the cells of stratum intermedium and papillary layer. The most drastic effect of TFP was a marked disappearance of enzymatic reaction of Ca++-ATPase from the plasma membranes of secretory ameloblasts, except for a weak persistent reaction in the basolateral cell surfaces of the infranuclear region facing the stratum intermedium. The cells of stratum intermedium and papillary layer, however, continued to react for Ca++-ATPase even after TFP treatment. Similarly, Na+-K+-ATPase activity in these cells was not inhibited by TFP administration. Ultrastructural examination of secretory ameloblasts revealed that administration of TFP caused no considerable cytological changes and did not act as a cytotoxic agent. These results suggest that secretory ameloblasts may have an active Ca++ transport system, which is modulated by an endogenous calmodulin.
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  • 130
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    Cell & tissue research 248 (1987), S. 79-88 
    ISSN: 1432-0878
    Keywords: Bone resorption ; Implantation ; Osteoclasts ; Osteopetrosis ; Mononuclear phagocytes ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Faulty osteoclasts, characteristic of the incisors-absent (ia) rat mutation of osteopetrosis, cause a resorptive defect which results in the persistence of immature, highly mineralized bone matrix. We implanted osteopetrotic bone subcutaneously into normal andia rats to determine ifia bone could induce functionally active and morphologically identifiable osteoclasts at the implant surface. Assays of45Ca released from the preparations showed that normal andia recipients were capable of equivalent cell-mediated release of Ca over a 2-week implant period, indicating that theia resorptive defect was not reproduced at the subcutaneous site. Freeze-thawed osteopetrotic bone released twice as much45Ca as normal bone. This difference was eliminated by collagenase treatment. Cellular profiles were similar in both normal andia animals regardless of the implant preparation. At 3 days after implantation, both bone and suture were surrounded by mononuclear cells. By 14 days, multinucleated cells appeared at the implant surfaces. Morphological comparison of implant-induced multinucleated cells and tibial osteoclasts indicated that bone-elicited multinucleated cells lacked the ruffled borders characteristic of normal osteoclasts or the extensive clear zones typical ofia osteoclasts, but more closely resembled suture-induced macrophage-polykaryons. We conclude that ectopically implantedia bone as compared to normal bone elicits a different functional response from structurally similar cell populations. Bone-elicited multinucleated cells could not be classified as active osteoclasts despite evidence of release of45Ca. Release of labeled Ca was probably due to the action of mononuclear phagocytes and macrophage-polykaryons rather than to osteoclastic resorption.
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  • 131
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    Cell & tissue research 248 (1987), S. 119-123 
    ISSN: 1432-0878
    Keywords: Odontoblasts ; Protein synthesis ; Denervation ; Neural regulation ; Wound healing ; Autoradiography ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Odontoblasts respond to occlusal trauma by increased elaboration of a matrix which is subsequently calcified to form reparative dentin. The purpose of the present study was to analyze quantitatively and compare the ability of odontoblasts to synthesize collagen after wounding in rats with an intact innervation (baseline) and in rats with sensory (inferior alveolar nerve, IAN) and/or sympathetic (superior cervical ganglion, SCG) surgical denervation. Surgery was performed 7 days prior to wounding. All rats had 1 mm of enamel and dentin removed from the occlusal surface of the first mandibular molar (resected side) with the contralateral tooth serving as a control. Rats were killed 1 h after injection with3H-proline on days 0, 5, 10 or 15 after wounding, and mandibles were removed and processed for autoradiography. Grain counts were performed over odontoblasts throughout the pulp horns for each time period and for control and experimental molars in intact (baseline) and denervated groups. When compared to the control baseline, the experimental baseline data showed increased3-proline uptake throughout the study with a peak at 5 days. When compared to the baseline data, IAN and SCG results demonstrated a delay or attenuation of the protein synthetic response. The results indicate that the sensory and sympathetic neural components may regulate odontoblastic response to wounding.
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  • 132
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    Keywords: Androgen ; Estrogen ; Pituitary ; Autoradiography ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Castrated male and female rats pretreated with dihydrotestosterone (DHT) were injected i.v. with 3H-estradiol (E2). Nuclear uptake and retention of 3H-E2 was measured in each of five cell types of the anterior pituitary gland using a combined quantitative autoradiographic and immunocytochemical procedure. In non-pretreated groups, each cell type bound a characteristic amount of ligand but no sex differences were apparent. DHT pretreatment, however, caused a significant decrease in 3H-E2 retention by gonadotrophs in both males and females. The treatment also caused a decrease in binding by lactotrophs and somatotrophs, but only in the females. No other cell types were altered. Thus, androgen appears to modulate E2 binding and retention by pituitary cells in both a cell-type and sexdependent manner. Our results also indicate that the inhibitory effects of androgens on E2 binding by the pituitary gland is more complex than can be explained by simple competition for the estrogen receptor.
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  • 133
    ISSN: 1432-0878
    Keywords: Lectin histochemistry ; Transport epithelia Immunolocalization: (Na++K+)-ATPase, carbonic anhydrase ; Kidney collecting ducts ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To identify precisely the structural and functional cell type in the collecting duct of the rat kidney expressing binding sites for Dolichos biflorus agglutinin (DBA), we stained serial paraffin sections of kidney with horseradish peroxidase-labeled DBA and with immunocytochemical methods for localizing (Na++K+)-ATPase and carbonic anhydrase II (CA II), enzymes found preferentially in principal and intercalated cells, respectively. Most principal cells expressing a strong basolateral staining for (Na+ + K+)-ATPase showed binding sites for DBA at their luminal surfaces. However, a minority of cells rich in CA II and showing morphologic characteristics of intercalated cells also expressed DBA binding sites at their luminal surface and apical cytoplasm. These data suggest that DBA cytochemistrycan provide a useful tool for studying the functional polarity of the main cell types of the collecting duct of the rat kidney.
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  • 134
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    Keywords: Immuno-electron microscopy ; Triple-immunogold-labeling ; CRF axon terminal ; Median eminence ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural appearances of axonal terminals containing corticoliberin (CRF) were examined in the rat median eminence prepared by a freeze-drying procedure. Immunolabeling was performed by using 5-, 8-, or 15-nm gold-antibody complexes for CRF, arginine vasopressin (VP) and methionine-enkephalin-octapeptide (Enk-8), singly or in combination. In intact animals, the CRF-containing secretory granules were only slightly labeled with goldanti-VP or -Enk-8. In adrenalectomized rats, granules within single axons appeared to be labeled with all the immunogold complexes. This intragranular colocalization of the three antigens was confirmed by using three neighboring sections of the same axon terminals which were stained separately with each one of the antibodies and visualized with the avidin-biotin-peroxidase complex method. The granules labeled for CRF had decreased 9 days after adrenalectomy but had increased again by day 21, while those labeled for VP steadily increased after adrenalectomy. However, this did not correspond with the appearances of cell bodies in the paraventricular nucleus; the cell bodies labeled for both CRF and VP steadily increased in number and in stainability. By contrast, Enk-8 immunoreactivity in the axonal terminals and cell bodies was not affected by adrenalectomy. These findings suggest that although the three peptides could be released simultaneously from the axonal terminals, VP may play some special role in the expression of CRF activity.
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  • 135
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    Cell & tissue research 248 (1987), S. 169-180 
    ISSN: 1432-0878
    Keywords: M-band structure ; Fibre type ; Skeletal muscle ; Cryo ultramicrotomy ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of the M-band in soleus (SOL) and extensor digitorum longus (EDL) muscles in newborn and four-week-old rats was studied using electron-microscopic techniques. In newborn rats, all myotubes and fibres in both muscles had an identical myofibrillar appearance. A five-line M-band pattern was seen in longitudinal sections and distinct M-bridges in cross-sections. The Z-discs were of medium width. On the other hand, in four-week-old rats, different muscle fibre types were observed on the basis of their myofibrillar pattern. In SOL two fibre types were distinguished in longitudinal sections. One had a four-line M-band pattern and very broad Z-discs, whereas the other type had five lines in the M-band and broad Z-discs. In EDL, three different myofibrillar patterns were observed. The M-bands were composed of three, four or five lines. Fibres had either thin, broad or medium Z-disc widths, respectively. In cross-sections of the SOL muscle one group of fibres showed indistinct M-bridges, whereas distinct M-bridges were seen in the other fibres and in all observed EDL muscle fibres. We conclude that initially there seems to be a single intrinsic program for M-band genesis; this program becomes modified upon the induction of functionally differentiated fibres.
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  • 136
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Liver ; Nucleolus ; 4-amino-pyrazolo(3,4-d)pyrimidine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The nucleolar ultrastructural changes produced in adrenal zona fasciculata cells and hepatocytes of rats by 4-aminopyrazolo(3,4-d) pyrimidine (4-APP), an inhibitor of the lipoprotein synthesis, are described. Male rats were injected intraperitoneally for three consecutive days with 4-APP in sodium phosphate buffer (50 mg/Kg/day). On the 4th day, the animals were sacrificed and their adrenals and liver were processed for EM. The nucleoli of the adrenal zona fasciculata cells showed nucleolar fragmentation with loss of their normal reticular appearance, separation of fibrillar and granular components, extensive vacuolization and evidence of fibrillar centers. The hepatocyte nucleoli also exhibited fragmentation. These changes seem to be the morphological counterpart of alterations in rRNA synthesis and processing, since 4-APP inhibits “de novo” purine synthesis and thus interferes with its incorporation into RNA and DNA.
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  • 137
    ISSN: 1432-0878
    Keywords: Macula densa ; Intercellular spaces ; Ultrastructure ; Frusemide ; Tubulo-glomerular feedback ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In situ drip-fixation of superficial glomeruli and tubules in the rat kidney verified the results obtained from high pressure perfusion fixation studies indicating that distinct spaces normally exist between the cells of the macula densa. Following treatment with frusemide these intercellular spaces between the macula densa cells became closed in both drip-fixed and perfusion-fixed kidneys. These findings suggest that the variability of extracellular compartmentation found in the macula densa is unlikely to be an artifact but most likely represents changes in the in vivo status of the macula densa.
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  • 138
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Alkaline phosphatase ; Small intestine ; Colchicine ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The purpose of this study was to investigate the effect of colchicine and vinblastine on the localization of alkaline phosphatase (AlPase) in rat duodenum in relation to structural changes. AlPase was localized on the membranes of rough endoplasmic reticulum, Golgi stacks, cytoplasmic vesicles, microvilli, on lateral plasma membranes, and in some lysosomes of the duodenal epithelial cells of rats treated with either lumicolchicine or 0.9% NaCl alone. Microvilli were most intensely stained, and AlPase-positive Golgi stacks were regularly distributed in the supranuclear regions. After colchicine treatment, microvilli were shortened and the staining intensity became weaker, whereas basal as well as lateral plasma membranes showed stronger staining. The AlPase-positive microvilli appeared not only on the luminal surfaces, but also on the baso-lateral plasma membranes and even on the surfaces of characteristic intracytoplasmic cysts. Golgi stacks became smaller and their distribution became less localized, and the staining intensity of the Golgi stacks became weaker. AlPase localization in rats treated with vinblastine was almost identical with that of rats treated with colchicine. Thus, colchicine and vinblastine appeared to have elicited a disorientation of intracellular transport of intestinal AlPase by inhibiting microtubule organization.
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  • 139
    ISSN: 1432-0878
    Keywords: Salivary glands ; Chondroitin sulfate ; Secretory granules ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The presence of chondroitin sulfate in secretory granules of the rat parotid gland and its saliva was revealed by radioactive sulfate incorporation, followed by isolation and partial characterization of the sulfated species contained within the granules and in the parotid saliva. 35SO 4 = was incorporated into chromatographically identical macromolecular material both in vitro, in a gland-slice system followed by isolation of granule contents, and in vivo as measured in the pure parotid secretion following intravenous administration of 35SO 4 = . The majority of the 35SO 4 = label appeared in a peak in the region where the family of acidic proline-rich proteins elute from a DEAE-Sephadex A-50 column. Papain digestion freed the sulfated material from the bulk of protein present in this peak, leaving sulfate-labelled material that chromatographed on Sepharose CL6B as a single peak corresponding to a molecular weight of 13000 daltons. The ratio of uronic acid to amino sugar in this sulfated peak was 0.56. The sulfated material was susceptible to degradation by chondroitinase AC. The presence of this chondroitin sulfate in secretory granules and saliva is consistent with previous suggestions that sulfated polyanions may play a role in formation and maturation of secretory granules.
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    Cell & tissue research 250 (1987), S. 257-266 
    ISSN: 1432-0878
    Keywords: Choriocapillaris ; Endocytosis ; Endothelium ; Eye ; Glycosaminoglycan ; Heparin ; Receptors ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Heparin-gold probes were used to localize regions of heparin binding on the luminal surface of the diaphragmed-fenestrated endothelium of the rat choriocapillaris. Structures of endothelial cells were unlabeled when rats were kept on ice and perfused with solutions at 4° C. When the heparin-gold quantity was doubled, only a few heparin-gold particles marked some diaphragms spanning fenestrae, vesicles and channels, parajunctional regions of the plasmalemma, and coated pits. With solutions at 4° C, but the animals kept at room temperature, all of these structures in the endothelial cells were labeled. This binding was not altered by the perfusion of low levels of unlabeled heparin, but was eliminated following high levels of unlabeled heparin, and by digestion with trypsin and pronase. At 37° C, heparin was localized to the above structures and, in addition, was internalized into coated vesicles, endosomes, and multivesicular bodies, but not other types of lysosomes. Some particles were found in tubules adjacent to the Golgi stacks. Heparin-gold was also transported to the abluminal front of the endothelium by vesicles. A desulfated, non-anticoagulant, fraction of heparin bound to gold was localized to the endothelium in the same manner. These results demonstrate receptors for heparin on the surface of a fenestrated endothelium. Furthermore, they show the pathway of endocytosis and transport of heparin. The possible roles of heparin in the function of the endothelium is discussed.
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  • 141
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    Cell & tissue research 250 (1987), S. 323-330 
    ISSN: 1432-0878
    Keywords: Tunicamycin ; β-Receptor ; Parotid gland ; Isoproterenol ; Secretion ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological and functional effects of tunicamycin were studied in rat parotid glands at the stage of the reformation of secretory granules following secretory stimulation by isoproterenol. Tunicamycin inhibited the incorporation of (3H)-mannose into the acid-insoluble fraction but had no effect on total protein synthesis as determined by the incorporation of (14C)-leucine. Thus the administration of tunicamycin in vivo inhibits the synthesis of mannose-rich glycoproteins in a manner similar to that in an in vitro system. The ultrastructure of the acinar cell showed little change following treatment with this drug, except that the number of reaccumulated secretory granules was greater than in the control. Amylase secretion stimulated by isoproterenol was inhibited in tunicamycin-treated cells, but did not decrease following treatment with N6,2′-O-dibutyryladenosine 3′-5′-cyclic monophosphate, a secretory stimulator bypassing the β-receptor. A radio-receptor assay using (3H)-dihydroalprenolol and direct localization using the fluorescent β-adrenergic blocker 9-amino-acridin propranolol showed a marked reduction in the binding activity of β-receptor following treatment with tunicamycin. Thus the inhibition of N-linked glycosylation appears to produce profound effects on the β-adrenergic receptor-adenylate cyclase complex of acinar cells, although the steps of the transport and the exocytotic discharge of secretory materials are not affected.
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  • 142
    ISSN: 1432-0878
    Keywords: Organum vasculosum laminae terminalis (OVLT) ; Capillaries ; Horseradish peroxidase ; Leptomeninges ; Blood-blood barrier ; Blood-cerebrospinal fluid barrier ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using intravenously injected horseradish peroxidase (HRP) as tracer, we demonstrate, that — in contrast to other neurohemal regions — the organum vasculosum laminae terminalis (OVLT) is composed of two functionally different divisions. Both parts of the OVLT are endowed with fenestrated capillaries which, however, obviously differ in their permeability for HRP. In one of these portions the neurohemal region remains unlabeled under the experimental conditions used, while the other portion, in analogy to the majority of neurohemal regions, is labeled by the tracer. The functionally different divisions of the OVLT are separated from one another by tanycytic processes and meningeal cells establishing a barrier between the two hemal compartments. The meningeal elements penetrate the organ in the form of an uninterrupted layer; they are continuous with the pia mater and produce large amounts of basal lamina-like material. Furthermore, they provide the delineation of the OVLT against the outer cerebrospinal fluid-containing compartment, a structural feature that is characteristic of both divisions of the OVLT and corresponds to the arrangement of meninges in all other portions of the brain where a blood vessel penetrates its surface.
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  • 143
    ISSN: 1432-0878
    Keywords: Anterior pituitary gland ; FSH cells ; LH cells ; Development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Serum concentration of follicle-stimulating hormone (FSH) in the juvenile female rat increases independently from that of luteinizing hormone (LH). The objective of this study was to determine whether this increase in serum FSH is accompanied by a proliferation of FSH-cells greater than the proliferation of LH-cells. Thus, we measured circulating FSH and LH in female rats on days 3, 10, 13, 17, and 20, calculated the percentages of adenohypophyseal cells that contained FSH or LH on days 3, 10, and 20, and determined whether cells containing only FSH existed on day 10. Serum FSH concentrations on days 10 and 13 were significantly greater than those on days 3, 17, or 20. No differences existed in serum LH concentrations. Cells containing FSH or LH were distributed throughout the entire adenohypophyses of 3, 10, and 20-day-old females. Clusters of these cells were observed in the ventral regions of adenohypophyses of 3-day-old females. The percentages of adenohypophyseal cells containing FSH increased significantly from ∼9% in 3-day-old rats to ∼17% in 10-day-old rats and then decreased to ∼14% in 20-day-old animals. At all ages the percentages of adenohypophyseal cells containing FSH were similar to the percentages of cells containing LH. At 10 days of age, all cells containing FSH also contained LH and all cells containing LH also contained FSH. These data suggest that the increase in serum FSH in the juvenile female rat is associated with an increase in the percentage of adenohypophyseal cells containing FSH and that at this time all cells containing FSH also contain LH.
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  • 144
    ISSN: 1432-0878
    Keywords: Primary immune response ; Thymus-independent antigens ; Development, ontogenetic ; Lymph nodes ; Spleen ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To examine the development of the postnatal immune response to thymus-independent type-1 (TI-type 1) and TI type-2 antigens, respectively, trinitrophenyl-lipopolysaccharide (TNP-LPS) or TNP-Ficoll was injected subcutaneously into the hind footpads of young rats of various ages. After 5 days the popliteal lymph nodes (PLNs) were removed and the localization pattern of specific anti-TNP antibody-containing cells was studied. The first specific antibody-containing cells elicited in rats by TNP-LPS appeared in animals at day 19 after birth. The results suggest that the development of these cells from lymphocyte to plasma cell occurs while they migrate from cortex to medulla. An unexpected finding was the low response to TNP-Ficoll in PLN; from 6 weeks after birth only very few specific antibody-containing cells were found. However, in the spleen numerous anti-TNP antibody-containing cells were found in the periarteriolar lymphocyte sheaths. To test the exclusive role of the spleen in the appearance of anti-TNP antibody-containing cells in lymph node after subcutaneous administration of TNP-Ficoll, the experiment was repeated in rats that had been splenectomized. Evidence from these experiments suggests that the spleen plays a major role in the appearance of the above-mentioned cells in lymph nodes.
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  • 145
    ISSN: 1615-6102
    Keywords: Silver staining ; Nucleolus ; Quantitative analysis ; Pineal gland ; Rat ; Oestrous cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Morphology, distribution and number of different argyrophilic aggregates appearing in pinealocyte nuclei have been studied during the rat oestrous cycle. Using the Ag-NOR reaction we have found two types of argyrophilic aggregates in pinealocyte nuclei. One of them, corresponding to the fibrillar centres and the surrounding fibrillar component, appears in the nucleoli. The silver grains are more loosely packed in the dense fibrillar component than in the fibrillar centres. A decrease in the number of these nucleolar argyrophilic aggregates was obtained at oestrous. A second type of silver grain aggregate was observed in the pinealocyte nucleoplasm. We call them “Ag-granule clusters” because they are similar to the interchromatin granule clusters and constitute the only silver deposit forming aggregates apart from the nucleolus. The number of Ag-granule clusters is significantly smaller at oestrous and meta-oestrous than at dioestrous and pro-oestrous.
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  • 146
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Proteinase inhibitor ; Cholecystokinin ; Protein synthesis ; Enzyme synthesis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Oral application of a single dose of a new synthetic proteinase inhibitor Camostate (Foy-305) in male Wistar rats was carried out together with studies of in vitro amino acid incorporation followed by separation of proteins by two-dimensional gel electrophoresis. The aim of this experiment was to analyze changes produced by the inhibitor in total protein and individual enzyme biosynthesis. Administration of 100 mg/kg Foy-305 resulted in significant inhibition of total pancreatic protein synthesis, without changes in fractional rates for individual enzymes. 50 mg/kg Foy-305 induced a 10-fold elevation of cholecystokinin (CCK) levels in serum; this persisted for 3 h and led to a significant increase in the total rate of protein synthesis with peak values at 6 and 9 h (78% and 84% above control levels, respectively), returning to control by 15h. Changes in fractional rates of synthesis occurred with a latency of 6 h and were restricted to amylase and the anionic form of trypsinogen and chymotrypsinogen. Amylase biosynthesis decreased by about 40% from control levels at 9 h to return to control levels by 15 h. Increased synthesis of trypsinogen and chymotrypsinogen was observed; this was also phasic. The results show similar enzyme-specific regulation as previously described for exogenous CCK stimulation and for the adaptation of the pancreas to diets enriched in protein. They demonstrate the effectiveness of pulsatory endogenous hormone release in the regulation of protein synthesis.
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  • 147
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    Cell & tissue research 249 (1987), S. 215-220 
    ISSN: 1432-0878
    Keywords: X-ray microanalysis ; Thymocyte ; Mitosis ; Sodium ; Potassium ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Elemental concentrations of rat thymocytes in vivo were studied by X-ray microanalysis of freeze-dried sections. Cells from different regions, the subcapsular zone, the cortex and the medulla were studied in thymic tissue from a number of animals. Generally thymocytes situated in the medulla had higher concentrations of K compared to those in the subcapsular zone. The concentration of Na in the nucleus was constant in the medulla in all animals but some variation in this element was seen between animals in the subcapsular zone. The distribution of K/Na ratio in individual thymocytes was different in each region of the thymus. Cells with low K/Na ratio (〈5) were predominant in the subcapsular zone, whereas cells with higher values for K/Na ratio were found in the cortex and medulla. The subcapsular zone is the region where mitotic cells are mostly situated. The finding of thymocytes with higher concentrations of Na and low K/Na ratios in this region is in accord with in vitro studies on thymocyte stimulation.
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  • 148
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    Cell & tissue research 249 (1987), S. 235-239 
    ISSN: 1432-0878
    Keywords: Satellite nucleoli ; Normal, stimulated and malignant hepatocytes ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The present study was undertaken to provide information on the presence and frequency of satellite nucleoli in cells with increased nucleolar biosynthetic activity. The number of hepatocytes containing satellite nucleoli was analyzed in rat liver, regenerating liver 18 h after partial hepatectomy and in Novikoff hepatoma ascites cells. In comparison with hepatocytes of normal liver, the number of both stimulated hepatocytes and malignant hepatoma cells containing satellite nucleoli was significantly reduced. The results also indicated that whereas most satellite nucleoli contain protein C23, a smaller percentage contain protein B23.
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  • 149
    ISSN: 1432-0878
    Keywords: Epididymis ; Ductus deferens ; Myosin ; Actin ; Fibronectin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The postnatal maturation of regions of the epididymis and intragonadal segment of the deferens duct was studied in the rat by light-and transmission electron microscopy. Maturation of the genital duct starts in the distal cauda epididymidis and ductus deferens after one week of life, and one week later, in the more cranial segments of the epididymis. Epithelial principal cells and peritubular contractile cells are structurally mature 35 days after birth. The synchronous changes of these cells indicate that the same factors control their postnatal maturation. The epithelial principal cells obtain an endocytotic apparatus and long stereocilia, whereas peritubular cells acquire contractile features. These changes are associated with a progressive increase in the immunoreaction for smooth muscle actin in both cell types. Smooth muscle myosin is detected in the apical region of the epithelial cells and the peritubular cell cytoplasm by day one of postnatal development. The differentiation of contractile cells in the wall is accompanied by progressive organization of the pericellular matrix into a continuous basement membrane. Although fibronectin is visible at birth, it is gradually removed from the tubule wall.
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  • 150
    ISSN: 1432-0878
    Keywords: Cardiac muscle cells ; Extracellular matrix ; Collagen fibers and filaments ; Immunohistochemistry ; Rat ; Hamster
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphology, composition, and function of struts that interconnect the lateral surfaces of cardiomyocytes were examined in the hearts of rats and hamsters. Methods included brightfield and fluorescent light microscopy, secondary and backscatter scanning electron microscopy, and transmission electron microscopy in conjunction with silver stain, cationic dye, and antibody to type-I collagen. These studies reveal a twisted, beaded appearance and a complex substructure of collagen fibrils embedded in a ground substance that has a positive reaction with cationic dye. A hierarchy of patterns of branching and attachment was seen among intercellular struts ranging in diameter from 0.1 μm to several urn. The hypothesis that struts tether not only the surfaces but the contractile lattices of laterally adjacent myocytes is supported by the following: (a) the attachments of struts to the collagen weave of the sarcolemma, often lateral to the level of Z bands, (b) the presence of collagen type I in a composite material arrangement, (c) the relative dispositions and configurational changes of struts and myocyte surfaces in various physiological states and induced, non-physiological perturbations of cardiac muscle, (d) the corrugated sarcolemmas with infoldings near Z bands, and (e) the continuity of intracellular filaments from Z bands to the inner aspect of the sarcolemma in relaxed and contracted myocytes. Implications of struts acting as tethers and sites for storage of energy in the motions of myocytes during the cardiac cycle are discussed.
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  • 151
    ISSN: 1432-0878
    Keywords: GABA-treatment ; Superior cervical ganglion ; Synaptic plasticity ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The superior cervical ganglion (SCG) of adult rats was exposed to γ-aminobutyric acid (GABA) by means of long-term microapplication. Serial sections were cut from GABA-treated and control ganglia, and subsequently the fine structure of individual synapses was investigated. The quantitative analysis of structural parameters of studied synapses showed that significant changes consisting of (1) a reduction in size of presynaptic axon terminals, (2) a decrease in the number of synaptic vesicles, and (3) a diminution in the extent of the postsynaptic membrane thickening at the dendritic side developed as an effect of GABA-treatment. These results provide morphological evidence that long-term application of GABA to the SCG exerts a combination of effects on both presynaptic and postsynaptic elements. It is suggested that the structural changes observed in the fine structure of individual synapses within the SCG may play an integral role in the development of the synaptogenetic action of GABA.
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  • 152
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    Cell & tissue research 249 (1987), S. 325-329 
    ISSN: 1432-0878
    Keywords: Renin release ; Epithelioid cells ; Osmosensitivity of renin release ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Superfusion with hypoosmotic solutions stimulates renin release from rat epithelioid cells adherent to isolated glomeruli. This stimulatory effect may be related to the observed swelling of the secretory granules; the swelling may markedly increase the probability of pre-exocytotic fusions between the granule and cell membranes, and consequently increase the frequency of exocytotic events.
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  • 153
    ISSN: 1432-0878
    Keywords: Cell membrane ; Transglutaminase ; Cysteine ; proteinase inhibitor ; Epithelium ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The chemical nature of the thickened plasma membrane of cornified cells in stratified squamous epithelium was investigated in comparison with that in noncornified epithelium. Localizations of transglutaminase, molecular weight 92000 daltons, and detection of epidermal cysteine proteinase inhibitor were effected with a monoclonal antibody and a monospecific rabbit anti-inhibitor immunoglobulin, respectively, directed to the antigens. N-(7-dimethylamino-4-methylcoumarinyl) maleimide was used to demonstrate S-S cross-linking. In all keratinizing epithelia, the enzyme and inhibitor were deposited on membranes of granular cells. S-S bonds were formed in cornification with the appearance of electron-dense material by the inner leaflet. Both enzyme and inhibitors occurred on the corneal epithelium, but S-S linkage and the thickened plasma membrane did not form even at the last stage of maturation. On the other hand, the internal vaginal epithelium in the proestrous stage without keratinization contained the enzyme, but neither inhibitor nor S-S linkage. Both antigens and S-S bonds were detected when keratinization proceeded during estrus. The staining patterns in the epithelium near the vaginal introitus were identical to those in the skin. Cuboidal and simple epithelia exhibited none of those constituents. The findings indicated that heterogenous components contribute to modification of the plasma membrane of cornified cells, but S-S cross-linkages are associated exclusively with formation of the ultrastructurally unique membrane structure. In addition, findings suggested hormonal regulation in the chemical modification of the membrane in estrogen-sensitive internal vaginal epithelium.
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  • 154
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    Cell & tissue research 249 (1987), S. 367-377 
    ISSN: 1432-0878
    Keywords: Ethane dimethanesulphonate ; Leydig cells ; Destruction ; Regeneration ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ethane dimethanesulphonate (EDS) was used as a specific cytotoxin to eliminate the Leydig cell population of the adult rat testis. Ultrastructural, morphometric and serum gonadotrophin and testosterone analysis was used to study the response of the intertubular tissue of the testis from 1 day to 10 weeks after EDS treatment. In control animals, the testis contained approximately 28 million Leydig cells and 8 million macrophages. Three to seven days after EDS treatment, Leydig cells were absent and serum testosterone was undetectable. Macrophage numbers increased three-fold by 3 days and returned to pretreatment values thereafter. At 2 and 3 weeks post-EDS, foetal-type Leydig cells (∼1–2 million per testis) appeared in proximity to perivascular and peritubular tissues, a feature also observed at 4 weeks when numerous such cells (∼15 million per testis) formed prominent clusters in perivascular and peritubular locations. Between 6 and 10 weeks after EDS treatment, the foetal-type Leydig cells were transformed morphologically into adult-type Leydig cells, they occupied central intertubular positions and their numbers were restored to pretreatment values. Regeneration of Leydig cells was reflected by elevated serum testosterone levels which returned towards the normal range. The results demonstrate the regenerative capacity of the testicular intertubular tissue and indicate a dual site of origin of Leydig cells which initially resemble foetal-type Leydig cells prior to establishing the adult-type Leydig cell population. The morphological pattern of Leydig cell regeneration suggests that in addition to gonadotrophic stimulation, local testicular factors from the seminiferous tubules may stimulate Leydig cell growth.
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  • 155
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    Cell & tissue research 249 (1987), S. 577-586 
    ISSN: 1432-0878
    Keywords: Parotid gland ; Duct cells ; Ferritin ; Endocytosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ability of the intralobular ducts of the rat parotid gland to take up protein from the lumen was examined after retrograde infusion of native and cationized ferritin. At high concentrations (3–10 mg/ml), cells of both intercalated- and striated ducts avidly internalized the tracers. No differences were noted in the mode of uptake or fate of native or cationized ferritin. Large, apical ferritin-containing vacuoles up to 5 μm in size were present in cells of the intercalated ducts after infusion for 15 min. Small, smooth-surfaced spherical or flattened vesicles and tubules containing ferritin were also observed, often in association with the large vacuoles. Ferritin uptake increased with increasing infusion time, up to 1 h. Uptake by the striated ducts was less consistent than by the intercalated ducts, and occurred mainly in small vesicles and tubules. Secondary lysosomes became labeled with ferritin in both cell types. Ferritin was not observed in the Golgi saccules, nor was it discharged from the cells at the basolateral surfaces. At low concentrations (0.3–1 mg/ml), uptake was reduced, especially by cells of intercalated ducts, and differences were noted in the behavior of the two tracers. Cationized ferritin was internalized mainly into vesicles and tubules of cells of striated ducts; little uptake of native ferritin occurred at low concentrations. These results demonstrate that the ductal cells of the salivary glands are capable of luminal endocytosis of foreign proteins. They also suggest that in addition to modifying the primary saliva by electrolyte reabsorption and secretion, and secretion of various glycoproteins, the ductal cells are able to reabsorb proteins secreted by the acinar cells.
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  • 156
    ISSN: 1432-0878
    Keywords: γ-Aminobutyric acid (GABA) ; Autoradiography ; Development, ontogenetic ; Duodenum ; Uptake sites ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The localization of high-affinity uptake sites for 3Hγ-aminobutyric acid (3H-GABA) was investigated in the rat duodenum during ontogenesis and also at the adult stage (from 15.5 days of fetal life up to 105 days post natum) by means of low- and high-resolution autoradiography. At all stages studied, specific endocrine cell types of the epithelium were labelled and an intense uptake was detected in the nervous tissue, especially in glial cells but also in scarce neurones. When the incubation medium was supplemented with β-alanine (1 mM), a blocker of the glial uptake for GABA, the labelling persisted only in endocrine cells and in few neurones. The intensity and the frequency of the labelling decreased at later periods compared to the earlier developmental stages. The GABA content of the duodenum as measured by a new ion-exchange column chromatography-HPLC-coupled method was higher in the early postnatal period compared to later stages. These observations suggest that GABA, in addition to being a neurotransmitter, may play an important role during development of the duodenum.
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  • 157
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    Cell & tissue research 248 (1987), S. 247-255 
    ISSN: 1432-0878
    Keywords: Collagen ; Slow and fast skeletal muscle ; Age ; Endurance training ; Endomysium ; Perimysium ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Intramuscular collagen in a slow (m. soleus) and a fast (m. rectus femoris) skeletal muscle was studied by biochemical, morphometric, and immunohistochemical methods. Wistar white rats of 1, 4, 10, and 24 months were used as experimental animals. Our aim was to evaluate the effects of life-long physical training (treadmill running, 5 days a week for 1, 3, 9, and 23 months depending on the age attained). The biochemical concentration of collagen was higher in m. soleus than in m. rectus femoris and it increased in youth and in old age in m. soleus. The trained rats had higher concentrations of collagen than the untrained rats at 10 and 24 months. The morphometrically measured area-fractions of both the endomysium and perimysium were higher in m. soleus than in m. rectus femoris. The age-related increase in intramuscular connective tissue was of endomysial origin. The immunohistochemical staining of type-I, -III, and -IV collagens indicated the more collagenous nature of m. soleus as compared with m. rectus femoris for all major collagen types; this was most marked for type-IV collagen of basement membrane. The results indicate that both age and endurance-type physical training further distinguish the slow and fast muscles with respect to their connective tissue.
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  • 158
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    Cell & tissue research 248 (1987), S. 297-303 
    ISSN: 1432-0878
    Keywords: Uterus (myometrium) ; Gap junctions ; Pregnancy ; Morphometry ; Freeze-fracturing ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In uterine smooth muscles, gap junction plaques rapidly form during the final stages of gestation. To investigate the related mechanisms, regional differences in myometrial gap junction development in rat uterus were examined quantitatively during delivery, using thin-section and freeze-fracture techniques in combination with light- and electron microscopy. Examination of implanted and nonimplanted horns in the unilaterally ligated rat bicornuate uteri, revealed no differences in the occurrence of gap junction plaques, but after 2 to 4 pups had been delivered, the contracted segments contained more gap junction plaques than did noncontracted segments examined immediately before delivery. In all segments, gap junctions were found more frequently in the circular muscle layers than in the longitudinal muscle layers. Gap junctions ranged in size from 0.002 μm2 to 0.52 μm2, but two-thirds were less than 0.1 μm2. The frequency of small gap junction plaques (less than 0.1 μm2) was higher in the noncontracted segment. These results suggest that gap junctions are dynamic structures, and that their formation is controlled not only by general hormonal factors, possibly involved in gap junction increases in the myometrium before delivery, but also by local factors, possibly related to the contraction, that may accelerate an increase in gap junction formation during delivery.
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  • 159
    ISSN: 1432-0878
    Keywords: 7B2 polypeptide ; Gastro-intestinal tract ; Endocrine cells ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunoreactivity to the polypeptide designated “7B2” recently isolated from human and porcine pituitary glands, appears to be consistently confined to neuroendocrine and endocrine cells in various tissues. In rat gut, immunoreactive 7B2 was found in endocrine-paracrine cells. Highly labeled cells were found in the antrum of the stomach and, cells with lower concentrations, in the fundus, duodenum, jejunum and ileum. Except for a few cells which were simultaneously positive for 5-hydroxytryptamine, and a few others showing Grimelius's reaction, “7B2” cells do not exhibit argentaffin and/or argyrophil character. The 7B2 polypeptide seems to be distributed amongst several different types of endocrine cells in the gut.
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  • 160
    ISSN: 1432-0878
    Keywords: Galanin ; Iris ; Choroid membrane ; Immunohistochemistry ; Trigeminal ganglion ; Superior cervical ganglion ; Calcitonin gene-related peptide ; Capsaicin ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The iris and choroid membrane of the adult rat contain nerve fibers expressing immunoreactivity to the neuropeptide galanin. The density and distribution of galanin-positive nerve fibers varied from iris to iris and, particularly, among animals. Smooth, non-terminal axons were seen running in nerve bundles consisting of otherwise negative fibers. From the choroid membrane these bundles reached the iris via the ciliary body. Axons were frequently seen to branch giving rise to a sparse system of varicose, single fibers in the dilator plate and sphincter area. Galanin-positive fibers were sometimes also seen outlining blood vessels. Capsaicin, in a dose that causes permanent depletion of substance P- and cholecystokinin-immunoreactive fibers in the iris, caused no change in amount of galanin-positive fibers. Removal of the superior cervical ganglion caused a rapid and pronounced increase in the number of galanin-immunoreactive nerve fibers. Similarly, removal of the ciliary ganglion appeared to increase galanin immunoreactivity, while removal of the pterygopalatine ganglion was less effective. Lesioning of the trigeminal ganglion caused a disappearance of galanin immunoreactivity. The sympathetectomy-induced increase was counteracted by capsaicin. Galanin-positive nerve cell bodies were present in both the superior cervical and the trigeminal ganglia. In the superior cervical ganglion, immunoreactive galanin did not seem to coexist with neuropeptide Y-positive cells; in the trigeminal ganglion, some galanin-positive cells also contained calcitonin gene-related peptide (CGRP) immunoreactivity, while most cells did not. In the iris, double-staining suggested that CGRP and galanin immunoreactivities were contained in different fiber populations. We conclude that the rat iris and choroid membrane contain a sparse plexus of nerve fibers expressing galanin-like immunoreactivity. It is suggested that these fibers are derived from the trigeminal ganglion. The iris is able to respond with a pronounced increase in number of galanin-immunoreactive nerve fibers to certain denervation procedures.
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  • 161
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Cyanoketone ; Corticosterone ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a 7-day administration of cyanoketone (CKT) on the adrenal zona fasciculata were examined in “normal” and dexamethasone/ACTH-infused rats. The drug caused a 48–56% decrease in the blood concentration of corticosterone, coupled with a 53–58% lowering in the activity of 3β-hydroxysteroid dehydrogenase (3βHSD), in both groups of animals. In the “normal” rats, CKT induced a significant hypertrophy of the zona fasciculata and its parenchymal cells, due to an increase in volume of the mitochondrial compartment and to proliferation of the smooth endoplasmic reticulum (SER), as well as a notable rise in both the volume of the lipid-droplet compartment and the intracellular concentration of total cholesterol. The activity of 11β-hydroxylase was conspicuously enhanced. All these responses of zona fasciculata cells to CKT did not occur in dexamethasone/ACTH-treated animals, and therefore they were considered to be non-specific and mediated by the augmented secretion of ACTH following lowering of the corticosterone level in the blood. In the dexamethasone/ACTH-infused rats, the only morphological change induced by CKT was a significant decrease in the surface area per cell and surface density of the SER, which was interpreted as the morphological counterpart (not masked by the increased level of circulating ACTH) of the drug-induced inhibition of the microsomal 3βHSD.
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  • 162
    ISSN: 1432-0878
    Keywords: Serotonin ; Neuropeptide Y ; Suprachiasmatic nucleus ; Radioautography ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The morphological substrate of putative serotonin (5-HT)/neuropeptide Y (NPY) interactions in thé suprachiasmatic nucleus (SCN) was investigated by combined radioautography and immunocytochemistry after intraventricular administration of (3H)5-HT in the rat. In the ventral portion of the SCN, the distribution of (3H)5-HT uptake sites overlapped closely the NPY-immunoreactive terminals. Previous investigations have shown that the dense 5-HT and NPY innervations of the SCN originate in different structures, i.e., the midbrain raphe nuclei and the ventral lateral geniculate nucleus, respectively. Accordingly, in the present study, destruction of 5-HT afferents by 5,7-dihydroxytryptamine was not found to induce any modification in NPY staining and, in ultrastructural immuno-radioautographic preparations, two distinct pools of axonal varicosities could be identified. Both 5-HT and NPY terminals established morphologically defined synaptic junctions, sometimes on the same neuronal target. Some cases of direct axo-axonic appositions between the two types of terminals were also encountered. These data constitute additional criteria for characterizing the cytological basis of the multiple transmitter interactions presumably involved in the function of the SCN as a central regulator of circadian biological rhythms.
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  • 163
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    Cell & tissue research 247 (1987), S. 179-185 
    ISSN: 1432-0878
    Keywords: Image analysis ; Morphometry ; Peroxisomes ; Catalase ; Cytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The feasibility of the application of a television-based image analyzer, the Texture Analysis System (TAS, Leitz Wetzlar, FRG) in conjunction with a light microscope for morphometric studies of hepatic peroxisomes has been investigated. Rat liver peroxisomes were stained with the alkaline-DAB method for localization of catalase and semi-thin (0.25 and 1 μm) sections of plastic-embedded material were examined under an oil immersion objective. The TAS detected the peroxisomal profiles selectively and determined their morphometric parameters automatically. The same parameters were obtained also by morphometric analysis of electron micrographs from the same material. The volume density of peroxisomes determined by TAS in semithin sections of normal liver, after correction for section thickness, is quite close to the corresponding value obtained by morphometry of electron micrographs. The difference is approximately 20%. In animals treated with the hypolipidemic drug bezafibrate, which causes proliferation of peroxisomes, TAS detected readily the increase in volume density of peroxisomes in semithin sections. In comparison with electron microscopy, however, the light-microscopic approach seems to underestimate the proliferation. The lower resolution of the light microscope and overlapping of neighbouring particles in relatively thick sections used for lightmicroscopic analysis may account for the differences. The present study has demonstrated the usefulness of automatic image analysis in conjunction with selective cytochemical staining of peroxisomes for morphometry of this organelle in rat liver. The light-microscopic approach is not only faster but is also extremely economical by obviating the use of an electron microscope.
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  • 164
    ISSN: 1432-0878
    Keywords: Myocyte subpopulations ; Hypertension ; Cell volume ; Doubling time ; Tetraploid cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Smooth muscle cells obtained from three distinct segments of the thoracic aorta of both Wistar Kyoto (WKY) and Spontaneously Hypertensive Rats (SHR) taken at different stages of development were studied in terms of their volume, DNA content in single cell suspensions, and doubling time in primary cultures. The proliferative activity and mean cell volume of myocytes from WKY rats increase along the thoracic aorta in a gradient from the aortic arch to the diaphragm. The slope of this gradient is increased in SHR because of an extension of the area that contains myocytes with low proliferative activity in primary cell culture and large cell volumes in suspension. Tetraploid myocytes are found in both strains and their proportions are larger in SHR than in WKY, specifically after the onset of hypertension. However, they appear to be evenly distributed along the thoracic aorta with a size distribution that is included in that of the diploid cells from the same area. It is suggested that changes in the structural properties of the aortic-cell compartment, associated with maturation and hypertension, reflect quantitative changes in the relative proportions of several myocyte subpopulations within the aorta of the rat.
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  • 165
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    Cell & tissue research 247 (1987), S. 215-225 
    ISSN: 1432-0878
    Keywords: Kidney ; Endoplasmic reticulum ; Ultrastructure ; Membrane transport ; Metabolism ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The spatial organization of endoplasmic reticulum (ER) was examined in all segments of rat nephron. Tissues were fixed with glutaraldehyde, impregnated “en bloc” with osmium tetroxide, prepared for and examined by standard (80–100 kV) and high voltage (1 mEV) transmission electron microscopy. In all proximal tubule cells, ER forms a continuous and extensive network of canaliculi and abundant fenestrated saccules which surround mitochondria and cytoplasmic bodies; the cage-like structure of the fenestrated saccules was most evident around the spherical mitochondria of the S3 segment. In the cells of the distal straight and convoluted tubules, the network consists mostly of canaliculi with rare non-fenestrated saccules. The ER network of canaliculi is particularly rich in intercalated cells, in contrast with its rudimentary appearance in the adjacent principal cells of the collecting tubule. In fact, in these cells there are few isolated ER cisternae and they are rarely impregnated. The nuclear envelope is well impregnated in most cells throughout the various segments. Segmental variations in ER organization and its relative abundance are most likely related to the well, established functional heterogeneity of the nephron segments. Moreover, the extensive and unique organization among mitochondria, ER and the basolateral membrane suggests that these three organelles function as a unit which is related to active electrolyte transport. In addition, because of its transepithelial organization, ER may well constitute a transcellular pathway for molecules.
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  • 166
    ISSN: 1432-0878
    Keywords: Calcergy ; Calciphylaxis ; Cutaneous calcinosis ; Experimental calcification ; Ultrastructure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Skin calcification induced by topical calciphylaxis was provoked by a subcutaneous injection of iron chloride in rats previously sensitized by dihydrotachysterol. A cutaneous topical calcergy was induced by an injection of potassium permanganate. An electron-microscopical study of the long-term evolution of both these models of calcification was made. After the initial stages, mineralization of the connective tissue continued by a secondary nucleation process without matrix vesicles. The mineral composed of needle-like structures, apatite in nature, was mainly deposited between and around collagen fibrils, and showed various arrangements in calcified plaques. Intrafibrillar calcification was rarely observed and appeared only in the later stages. The extension of calcified deposits then stopped. Finally, there was a fragmentation of the mineralized area which was progressively surrounded by uncalcified collagen fibrils. A demineralization process, caused by cells such as macrophages and multinucleated giant cells, rather than a resorption of the calcified deposits, was noted. It is important to emphasize that, in both models of ectopic calcification, an evolution toward ectopic ossification was never observed, which is perhaps due to the absence of extensive resorption mechanisms.
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  • 167
    ISSN: 1432-0878
    Keywords: Adrenal cortex ; Aminoglutethimide ; Corticosterone ; Morphometry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of a 7-day administration of aminoglutethimide (AG) on the adrenal zona fasciculata were examined in “normal” and dexamethasone/ACTH-treated rats. There was a 70–74% decrease in the concentration of corticosterone in blood, but no conspicuous qualitative changes suggesting cell degeneration occurred. Morphometry showed that AG induced a significant hypertrophy of the zona fasciculata and its parenchymal cells only in “normal” animals, which was due to an increase in the volume of the mitochondrial compartment and to proliferation of the smooth endoplasmic reticulum. This response to AG was considered to be non-specific and mediated by the enhanced secretion of ACTH following the decrease in the blood level of corticosterone. AG administration significantly increased the volume of the lipid-droplet compartment and the number of intramitochondrial lipid-like inclusions in both groups of animals. These changes were interpreted as the morphological counterpart of the AG-induced block of cholesterol utilization in steroid synthesis.
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  • 168
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    Cell & tissue research 248 (1987), S. 491-497 
    ISSN: 1432-0878
    Keywords: Intestine, small ; Collagen ; Submucosa ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Whole-mount preparations of the submucosa were made from the small intestine of rats, guinea-pigs, rabbits and sheep. In the distended intestine the collagen fibres ran straight and approximately parallel to the serosal surface. They formed a characteristic lattice, with two arrays of fibres running diagonally in a clockwise and an anticlockwise direction, and making an angle of 50°–55° with the longitudinal axis of the intestine. This collagenfibre lattice was flexible and changed with the movements of the intestinal wall; when the radial distension predominated, the angle between collagen fibres of the submucosa and longitudinal axis of the intestine increased to 60°–65°, and when the longitudinal distension predominated the angle decreased to about 30°.
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  • 169
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    Cell & tissue research 248 (1987), S. 505-510 
    ISSN: 1432-0878
    Keywords: Textile blood-vessel prosthesis ; Aorta ; Neointima formation ; Dog ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The formation of a neo-intima in textile prostheses implanted in the rat and dog aorta was studied by means of light- and scanning electron microscopy. Two independent cellular layers (the superficial and deep ingrowth layers) developed on the free surface and under the fibrin layer initially deposited on the inner surface of the prostheses. The superficial ingrowth layer invades the prosthesis from both the proximal and distal aortic stumps and extends over the primary fibrin layer, or replaces it. This layer consists mainly of smooth muscle cells of the triangular aortic type covered by endothelial-like cells. The deep ingrowth layer originates from cellular elements of the prosthetic bed. Fibroblasts, myofibroblasts and spindle-shaped smooth muscle cells invade the fibrin layer through the interstices of the fabric structure of the prosthesis. Precursors of endothelial cells, however, are absent from this population. The superficial and the deep ingrowth layers may become joined by progressive replacement of the fibrin layer, but remain distinguishable because of their different cellular components. When a continuous cellular layer is established on the inner surface of the prosthesis, and this is then covered by endothelial-like cells, the neo-intima formed remains stable during long-term studies.
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  • 170
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    Cell & tissue research 248 (1987), S. 699-702 
    ISSN: 1432-0878
    Keywords: Albumin ; Ovarian follicles ; Granulosa cells ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The purpose of this study was to investigate whether albumin (Alb) can be detected in ovarian rat granulosa cells. Using immunocytochemistry and morphometrics, the percentages of Alb-positive follicles (follicle-index), of Alb-positive granulosa cells (granulosa-index), and of strongly reacting follicles (intensity-index) were evaluated in intact and regressing follicles of different diameter groups during different stages of the estrous cycle. In intact follicles, the follicle- and the granulosa-index increased from small-sized to large-sized follicles. Although the follicle-index did not change in any group during the stages of the estrous cycle, the granulosa-index was higher during proestrus than during the other stages. Intact follicles showed a stronger immunoreactivity than regressing follicles throughout the stages of the estrous cycle. Thus, Alb may be a requirement for the control of follicle growth in fertile rats. This Alb function may be attributable to Alb binding to specific cell-membrane components followed by the intracellular uptake of Alb-bound substances.
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  • 171
    ISSN: 1432-0878
    Keywords: Microtubules ; Terminal web ; Small intestine ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The terminal web (TW) region of mature absorptive cells in the small intestine of the rat contains an elaborate cytoskeleton which supports the apical microvillus membrane. In studies regarding the structural organization of the cytoskeleton and associated proteins in the small intestine, microtubules have not been mentioned as components of the TW. By transmission electron microscopy of conventional resin-embedded sections of rat small intestine, we observe many microtubule profiles in the TW of mature absorptive cells. These microtubules are found in various orientations, although most course parallel to the long axis of the cell, and many microtubule profiles are seen in close association with smooth-surfaced vesicles.
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  • 172
    ISSN: 1432-0878
    Keywords: Teeth ; Dental pulp ; Periodontium ; Neurofilament protein ; Immunohistochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of nerve fibers in molars, periodontal ligament and gingiva of the rat shows a complex pattern. Decalcified material including the alveolar bone was sectioned in three different planes and stained by means of immunohistochemistry for detection of the neurofilament protein (NFP); the immunoreactive neural elements were clearly visualized in three-dimensional analyses. NFP-positive nerve fibers formed a subodontoblastic plexus in the roof area of the dental pulp; some of them entered the predentin and dentin directly through the dentinal tubules. This penetration was found mainly in the pulp horn, and was limited to a distance of about 100 μm from the pulpo-dentinal junction. In the periodontal ligament, NFP-positive nerve fibers were found densely distributed in the lower half of the alveolar socket. Two types of nerve terminals were recognized in the periodontal ligament: free nerve endings with tree-like ramifications, and expanded nerve terminals showing button- or glove-like shapes. The former tapered among the periodontal fibers, some even reaching the cementoblastic layer. The latter were located, frequently in groups, within the ligament restricted to the lower third of the alveolar socket. A well-developed plexus of NFP-positive nerves was revealed in the lamina propria of the free gingiva, the innervation being denser toward the epithelium of the gingival crevice. The characteristic distribution of NFP-immunoreactive nerve fibers revealed in this study is discussed in relation to region-specific sensations in the teeth and surrounding tissues.
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  • 173
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Secretion granules ; Effect of feeding ; Carbachol ; Stereology ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The size, number and volume per cell of secretion granules in rat exocrine pancreas have been measured using stereological techniques. The changes which occur as a result of feeding starved animals (90 min) or stimulating lobular fragments in vitro with carbachol are documented. In fasted animals mean acinar cell volume was estimated as 1670 μm3 and the cells contained an average of around 450 secretion granules with a corrected mean diameter of 0.70 μm. They occupied around 7% of cell volume. After feeding mean cell volume was about 1300 μm3 and the cells contained an average of about 190 granules per cell with a mean diameter of 0.58 μm. They occupied 3% of cell volume. A shift in the size frequency distribution of granule diameters occurred as a result of feeding. In vitro experiments in which lobules were induced to secrete with carbachol (10μM, 3 h, 37° C) had a similar effect. Mean cell volume was reduced from around 1760 μm3 to 1360 μm3, mean granule number from around 420 per cell to 180 per cell and the volume density of granules was reduced from about 8% to 3% of cell volume. There was no significant change in mean granule diameter or shift in the size-frequency distribution of granule diameters. Incubation of tissues with cycloheximide (1 mM, 3 h, 37° C) did not prevent secretion by carbachol but it prevented replacement of granules. As a consequence, depletion by carbachol was greater in the presence of cycloheximide, the granules being reduced to around 110 per cell and to only 2.5% of cell volume. We conclude that feeding causes a preferential loss of larger granules and that during secretion replacement of granules occurs. Some of these granules are smaller than those evident in the glands of starved animals.
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  • 174
    ISSN: 1432-0878
    Keywords: Brain ; Immunohistochemistry ; Natural killer cells ; Monocytes ; Granulocytes ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study reports a specific cross-reactivity of the three anti-human-hematopoetic-cell monoclonal antibodies, anti-Leu-7 (HNK-1), anti-Leu-11a (NKP-15), and anti-Leu-M1 (MMA), with different epitopes in the brain of the adult rat. The distribution of these epitopes in rat brain is determined by means of immunohistochemistry in paraffin-embedded frontal serial sections. The reaction pattern of anti-Leu-11a monoclonal antibody is very similar to that of polyclonal antibodies against the myelin basic protein. Both antisera give a specific reaction with myelinated fibers. Immunoreaction products with the anti-Leu-7 monoclonal antibody are found as diffuse, mostly punctiform material in the neuropil and even more evident as small granules coating the cell surface of many neurons. In the white matter anti-Leu-7 reveals a moderate reactivity, which occurs predominantly as spots and fine-stranded material within the myelinated fiber tracts. Anti-Leu-M1 immunoreactivity is present between myelinated fiber bundles of the white matter, where it has a reticulate appearance, and as fine-granulated material within the grey matter of the cortex and the nuclei. The characteristic feature in the grey matter is that of irregularly shaped immunopositive plaques, which are often located around small blood vessels. The cytoplasm of glial and neuronal cells appeared negative with this MAB. The exact topographical distribution of the Leu-7 and Leu-M1 epitopes throughout the rat brain is described. The present hypotheses concerning the nature of this shared antigenicity between hematopoetic cells and nervous tissue are discussed.
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  • 175
    ISSN: 1432-0878
    Keywords: Alpha-bungarotoxin ; Autoradiography ; Cholinergic receptors ; Electron microscopy ; Suprachiasmatic nucleus ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of (125I) alpha bungarotoxin (α-BTX) binding sites in the suprachiasmatic nucleus (SCN) of the adult female rat was examined by electron-microscopic autoradiography. The ultrastructural distribution of silver grains was analysed by line source, direct point count, and 50% probability circle methods. Real grain distribution was significantly different from that of randomly generated hypothetical grains. Line source analysis demonstrated two populations of sources: one associated with membranes, and one inside neuronal structures. Probability circle analysis of shared grains indicated that membrane-bound-radioactive sources were mainly asssociated with axo-dendritic appositions. Only a small proportion of labeled neuronal interfaces exhibited synaptic differentiations in the plane of section. However, the compartment containing synaptic terminals was the most enriched when comparing real to hypothetical grains. Probability circle analysis of exclusive grains demonstrated that sources that were not associated with neuronal plasma membranes were likely to be within nerve cell bodies and dendrites. It is concluded that the majority of specifically labeled α-BTX binding sites in the SCN is membrane bound, and may be associated with axodendritic synaptic transmission. The presence of a significant proportion of the label in the soma and dendrites of suprachiasmatic neurons 24 h after ventricular infusion suggests that some of the labeled binding sites (junctional or nonjunctional) may be internalized within these two compartments.
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  • 176
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    Cell & tissue research 250 (1987), S. 29-33 
    ISSN: 1432-0878
    Keywords: Pituitary gland, pars anterior ; Cysts ; Transplantation ; Differentiation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hemipituitary glands from 30 rats were isotransplanted under renal capsules. At 1, 2, 4, 7 and 20 days after transplantation, the grafts were examined by light and electron microscopy. Two days after transplantation, the central area of graft showed necrosis; however, the peripheral area, where marginal cells of Rathke's cleft were ingesting the remnants of necrotic glandular cells, survived. Four days after transplantation, mitotic figures of marginal cells were observed. Seven days after transplantation, the damaged area of the graft disappeared, and Rathke's cleft was completely lined by marginal cells. Remnants of necrotic glandular cells were not seen in intercellular spaces or in the cytoplasm of marginal cells. Cystlike structures formed in the grafts; some were connected to Rathke's cleft by narrow cavities. The cavity-lining cells of the cysts were agranular and similar to those that lined Rathke's cleft. At 20 days after transplantation, granular cavity-lining cells appeared. It is suggested that marginal cells of immature rats can differentiate into granular cells.
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  • 177
    ISSN: 1432-0878
    Keywords: Epididymis ; Basement membrane ; Anionic sites ; Differentiation ; Androgen ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Anionic binding sites in the lamina densa of the basement membrane of the rat epididymal epithelium were demonstrated ultrastructurally with the use of cationized polyethyleneimine (PEI). Enzyme digestion with heparitinase removed the anionic sites, indicating that they consist largely of heparan sulfates. The anionic sites are present as early as the 16th day of gestation on the interstitial face of the lamina densa; later during gestation they are localized on both faces of the lamina densa without further modification after birth. The distribution of the anionic sites was identical all along the epididymal duct. After castration and ligation of efferent ducts or in the state of cryptorchidism the sites were more numerous and located inside the thicker portion of the lamina densa. These alterations were more prominent in the initial segment compared to the distal segments, suggesting a differential androgen dependence of the reactive sites and their patterns of distribution.
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  • 178
    ISSN: 1432-0878
    Keywords: Osteogenesis ; Marrow stromal precursors ; Collagen ; Culture in vivo ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Diffusion chambers containing bone marrow cells from adult rats were implanted intraperitoneally into rat hosts and cultured in vivo for up to 64 days. Biochemical and histological analyses of the contents of the chambers demonstrate that a connective tissue consisting of bone, cartilage and fibrous tissues is formed by precursor cells present in marrow stroma. The amounts of osteogenic tissue and DNA are directly correlated with time of implantation and with number of cells inoculated. In the chambers there is initial formation of fibrous tissue which is strongly reactive to collagen type III, laminin and fibronectin. In areas of osteogenesis which appear later within this fibrous anlage, expression of collagen type III, laminin and fibronectin decrease and collagen types I and II increase in association with bone and cartilage respectively. Where osteogenesis does not develop, fibrous tissue continues to express collagen type III. The sequential expression of the different extracellular matrix components is similar to that previously observed during osteogenic differentiation in embryonic and adult developmental systems. It is concluded that the formation of fibrous and osteogenic tissues in diffusion chambers by precursor cells present in adult marrow, resembles the normal developmental process.
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  • 179
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    Cell & tissue research 250 (1987), S. 197-204 
    ISSN: 1432-0878
    Keywords: Third ventricle ; Intraventricular vessels ; Recess ; Development ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Light and electron microscopy of the hypothalamic ventricle in neonatal rats demonstrate morphological specializations of the ventricular wall at the level of the premammillary region of the third ventricle. The morphological features are: (1) A ventricular recess that we have called the “hypothalamic dorso-lateral recess” (HDR). (2) The presence of intraventricular capillaries near the dorsolateral recess. (3) The HDR possessing a specialized ependymal lining; this consists of non-ciliated cells with short microvilli and bleb-like processes. (4) The existence of cerebrospinal fluid-contacting neurons within the HDR. (5) The presence of numerous phagocytic supraependymal cells. The HDR is not found in adult rats. This indicates that the dorso-lateral recess may play a physiological role during development.
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  • 180
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    Cell & tissue research 250 (1987), S. 21-27 
    ISSN: 1432-0878
    Keywords: Glomus cell ; Acetylcholinesterase ; Catecholamines ; Carotid body ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The localization of acetylcholinesterase (AChE) was investigated at the cellular and subcellular levels in dissociated cell cultures of the carotid body of the neonatal rat, prepared by the methods of Fishman and Schaffner (1984). In the presence of iso-OMPA, which blocks non-specific cholinesterase, staining was confined almost exclusively to glomus-cell clusters and occasional isolated cells. These clusters grow as discrete islands scattered throughout the culture and display typical catecholamine (CA) fluorescence as in vivo. AChE staining was abolished or reduced by the cholinesterase inhibitors eserine (30–100 μM), or (the poorly lipid soluble) echothiophate (8 (μM). Processing of the same culture sequentially for the demonstration of both AChE and CA revealed that glomus-cell clusters and individual glomus cells were consistently positive for both. In electron micrographs AChE reaction product was associated intracellularly with the nuclear envelope and cytoplasm of glomus cells (identified by their characteristic dense cored granules), as well as extracellularly with the boundaries of contiguous glomus cells. Significantly, reaction product occurred in some glomus cell profiles that had both dense-cored and clear (cholinergic-like) vesicles. These findings are discussed in the context of a possible dual (adrenergic/cholinergic) function status of glomus cells in the rat's carotid body.
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  • 181
    ISSN: 1432-0878
    Keywords: Neurofilaments ; Glial fibrillary acidic protein ; Sympathetic ganglia ; Intraocular transplantation ; Rat ; Guinea pig
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The presence of neurofilament (NF)-like and glial fibrillary acidic protein (GFAP)-like immunoreactivities was studied in sympathetic ganglia of adult rats and guinea pigs during normal conditions and after perturbation. In the superior cervical ganglion (SCG) of normal rats, many ganglion cells and nerve fibers show NF immunoreactivity. Some of these nerve fibers disappear after preganglionic decentralization of SCG; this indicates the presence of a mixture of preand postganglionic NF-positive nerves in the ganglion. Cuts in both preand postganglionic nerves result in a marked increase in GFAP immunoreactivity in SCG, whereas NF immunoreactivity increases in nerve cell bodies after preganglionic cuts. Only a few ganglion cells show NF immunoreactivity in the normal SCG of guinea pig. All intraganglionic NF-positive nerves are of preganglionic origin; decentralization abolishes NF immunoreactivity in these nerve fibers. The inferior mesenteric ganglion, the hypogastric nerves and colonic nerves in guinea pigs contain large numbers of strongly NF-immunoreactive nerve fibers. When the SCG of adult rat is grafted to the anterior eye chamber of adult rat recipients, both ganglionic cell bodies and nerve fibers, forming on the host iris from the grafted ganglion, are NF-positive. As only the perikarya of these neurons normally exhibit NF immunoreactivity, and the terminal iris arborizations are NF-negative, it appears that the grafting procedure causes NF immunoreactivity to become more widespread in growing SCG neurons.
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  • 182
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    Cell & tissue research 250 (1987), S. 215-220 
    ISSN: 1432-0878
    Keywords: Gossypol ; Ovarian follicle ; Granulosa cells ; Lysosomes ; Smooth endoplasmic reticulum ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ultrastructural changes were observed in the oocytes and granulosa cells of the ovarian follicles of sexually mature female rats treated daily for 60 days with gossypol acetic acid at a dosage known to induce sterility in male rats (20 mg/kg body weight, orally). The changes included an increased lysosomal population in the ooplasm and a reduced, poorly developed smooth endoplasmic reticulum in the granulosa cells. The latter changes suggest a suppression of the secretory activity of the granulosa cells.
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  • 183
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    Cell & tissue research 250 (1987), S. 641-648 
    ISSN: 1432-0878
    Keywords: Kidney ; Interstitial cells ; Lysosomes ; Sulfated glycosaminoglycans ; Tilorone ; Mucopolysaccharidosis ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This investigation provides histochemical evidence for lysosomal storage of sulfated glycosaminoglycans (GAGs) in the interstitial cells of the renal cortex and in macrophage-like cells of the renal medullary zones of rats chronically treated with the drug tilorone. This compound is known to interfere with lysosomal degradation of sulfated GAGs; therefore cells that develop GAG-storage can be assumed to be involved in the turnover of GAGs. In view of this consideration, the most remarkable and still unexplained finding was that the intrinsic interstitial cells in the papilla, which is known to be particularly rich in sulfated GAGs, did not show the cytological symptoms of lysosomal GAG-storage. The present findings may stimulate further studies focused on the cellular sites of turnover of the sulfated GAGs present in the renal medullary interstitium.
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  • 184
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    Medical & biological engineering & computing 25 (1987), S. 386-390 
    ISSN: 1741-0444
    Keywords: Central caudal artery ; Electrical impedance plethysmography ; Electromagnetic flowmetry ; Peripheral blood flow ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The impedance Z, the derivative of Z with respect to time t, dZ/dt, and blood flow F have been measured simultaneously in the central caudal artery of a series of anaesthetised rats. The results of the experiments were expressed in the relationship derived from the Windkessel theory where f(t)=adz(t)/dt+βz(t), in which α and β are constants and f(t) and z(t) express the pulsating fractions in the blood flow F and the impedance Z, respectively. The correlation between the peak-to-peak values of f(t) and of adz(t)/dt+βz(t) was 0·96. The correlation between the mean flow fo and the peak-to-peak value of f(t) was 0·74. Furthermore, even when the mean flow was zero, adz(t) still existed. The theoretical model was tested against volume flow measurements made using an electromagnetic flowmeter and was found to correlate well. Theoretical estimates of vessel calibre also accord with measured values.
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  • 185
    ISSN: 1432-0878
    Keywords: Cholecalcin (vitamin D-dependent calcium-binding protein) ; mRNA ; Uterus ; In situ hybridisation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The molecular cloning of a cDNA fragment synthesised from rat duodenal mRNA coding for cholecalcin (calbindin), a 9000 Mr vitamin D-induced calcium-binding protein (CaBP), has been previously described. DNA/RNA hybridisation assays have been used to examine CaBP mRNA production in the uterine horns and duodena of pregnant (21 day) rats using the cloned CaBP cDNA. Northern hybridisation studies showed that the 32P cDNA sequence hybridised to a single 500–600 nucleotide species in both the uterus and the duodenum, thus demonstrating identical CaBP mRNA processing in both tissues. Dot blot hybridisation studies showed that the CaBP mRNA concentration was greatest in the duodenum while that of the uterine horns was about 10% of the duodenal level. The observed differences in CaBP mRNA levels correlate well with the in vivo CaBP concentrations. In situ hybridisation histochemistry using 3H cDNA revealed that CaBP mRNA visualised by silver grains was found in all the parts of the endometrium and the myometrium. However, CaBP mRNA was more concentrated in the outer and inner muscular fibres and in the luminal cells of the endometrium than in the stroma cells. These results demonstrate that the CaBP gene is expressed in specific cells of the rat uterus.
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  • 186
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Proteinase inhibitor ; Feedback regulation ; Cholecystokinin ; Fine structure ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Application of a single dose of a new type of proteinase inhibitor camostate (FOY-305) via orogastric tube was used in rats to study the dose-response relationship of resulting pancreatic stimulation. Doses up to 10 mg/ kg failed to elicit any response, while significant decrease in enzyme content and increase in serum CCK-levels were observed with doses ranging from 25 to 400 mg/kg. A single dose of 100 mg/kg was selected for a time-sequence analysis, which revealed a 60 to 70% depletion of enzyme stores persisting over 6 h and reverting to control levels by 12 h. Peak increases in serum CCK-levels (15-fold above the elevation observed after regular food intake) were found after 30 min and persisted as an 8-to 10-fold elevation for at least 3 h, then declined to control levels by 9 h. This prolonged endogenous hormone release and resulting pancreatic stimulation were also verified in a separate group of animals in which volume, protein, and enzyme output were measured after cannulation of the pancreatic duct. While volume secretion was not altered by feeding a single dose of 100 mg/kg FOY-305, protein and enzyme output increased 2-to 3-fold over a period of 7 h. Fine-structural analysis of the pancreas demonstrated efficient depletion of zymogen granules from acinar cells with all doses between 50 and 400 mg/kg, accompanied by the appearance of membrane material in the acinar lumina at 3 and 6 h. The same transient increase in the number of lysosomal bodies predominantly containing mitochondria with all doses above 50 mg/kg was interpreted as increased organelle turnover due to persisting hormonal stimulation.
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  • 187
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    Cell & tissue research 248 (1987), S. 49-54 
    ISSN: 1432-0878
    Keywords: Enterochromaffin cells ; Serotonin ; Duodenum ; Immunocytochemistry ; Electron microscopy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Enterochromaffin cells of the rat duodenum have been studied immunocytochemically by use of a specific antiserum to serotonin. At the light-microscopic level serotonin immunoreactivity was observed in enterochromaffin cells located in the epithelium of the duodenal mucosa. Most of the serotonin-immunoreactive material was localized to the basal portion of the enterochromaffin cells, but small amounts of immunoreactive material were regularly observed in the apical portion. At the electron-microscopic level serotonin immunoreactivity in enterochromaffin cells was found to be concentrated over the dense cores of the cytoplasmic granules. The majority of these granules was located in the basal cytoplasm of the enterochromaffin cells, but serotonin-immunoreactive granules were also observed in the apical cytoplasm immediately beneath the microvilli. These observations indicate that duodenal enterochromaffin cells are bipolar and that they secrete serotonin both basally, to the circulation, and apically, to the gut lumen. Rat duodenal enterochromaffin cells thus appear to have an exocrine as well as an endocrine function.
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  • 188
    ISSN: 1432-0878
    Keywords: TRH ; Insulin ; Pancreas ; Streptozotocin ; Regeneration ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Streptozotocin treatment at birth induces, in the pancreas of rats, first depletion of insulin and thyrotropin-releasing hormone and then early regeneration ofβ cells and insulin, but not TRH. This study was undertaken to investigate whether the reduction in pancreatic TRH content can be associated with changes in the intensity and the distribution of TRH-immunoreactivity, and to follow the pattern of regeneration ofβ cells through insulin- and TRH-immunoreactivity. In control animals, strong TRH-immunoreactivity was seen in insulin-containing cells on days 1–4 after birth. At day 7, the TRH-immunoreactivity was already decreased. In contrast, insulin-immunoreactivity was present throughout the neonatal period. A sparse population of cells near ducts also contained both TRH- and insulin-immunoreactivity at 1–2 days age. In streptozotocin-treated animals, TRH-immunoreactivity is found only in a few scattered insulin-containing cells in altered islets on days 1–4. Near the ducts, there were new insulin-containing cells which did not contain TRH. From day 7 regeneration of endocrine cells was characterized by new, typical islets, but these contained insulin-, but not TRH-immunoreactivity. These findings suggest a differential control of the biosynthesis of insulin and TRH within the pancreas.
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  • 189
    ISSN: 1432-0878
    Keywords: Neuromuscular synapse ; Lectin histochemistry ; Dolichusbiflorus agglutinin ; Synaptogenesis ; Denervation ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The binding of agglutinin fromDolichus biflorus (DBA) and other lectins (Concanavalin A, agglutinin from wheat germ and lectin fromBandeiraea simplicifolid) to synaptic and extrasynaptic portions of the basal lamina of muscle fibers, was studied with histochemical methods. In rat muscle, DBA-binding is specifically detected at the basal lamina of neuromuscular junction. However, long-term (6 months) denervated end-plate in adult rat muscle failed to bind DBA. During normal development, synaptic DBA receptors appear later than acetylcholine receptors or acetylcholinesterase at the rat neuromuscular junction. Generalized DBA-binding to motor end-plates is first visualized in 3-day-old rats, but section of sciatic nerve in 1-day-old rats prevents the appearence of synaptic DBA-binding on the leg end-plates. It is suggested, therefore, that the synaptic DBA receptors could be related to the postnatal stabilization of rat neuromuscular synapses.
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  • 190
    ISSN: 1432-0878
    Keywords: Gonadoliberin ; Pituitary gland, pars anterior ; Gonadotrophs ; Autoradiography ; Cryoultramicrotomy ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary To identify anterior pituitary cell types containing GnRH binding sites and to study the internalization process of this peptide by target cells under physiological conditions, autoradiography was performed on rat anterior pituitaries removed at specific time intervals (2–60 min) after intravenous injection of mono-radioiodinated 125I-GnRH into intact males. At electron-microscopic level, gonadotrophs and lactotrophs appeared to contain silver grains. Concomitant administration of an excess of unlabeled GnRH with the radioiodinated hormone prevented this localization indicating the specificity of the reaction. The time-course study in gonadotrophs showed that 2 min after injection silver grains could be found over the plasma membrane, secretory granules and nuclear membrane. Similar results were observed 5 and 15 min after injection. Extensive label was observed over the nucleus and nuclear membrane 15 to 60 min after injection. The injection of a radioiodinated GnRH agonist [D-Trp6, Pro9 (Net), DesGly10]-GnRH produced comparable results. In contrast, the injection of 125I-[D-pGlu1, D-Phe2, Trp3,6]-GnRH, an antagonist of GnRH, produced positive labeling only at the plasma membrane without internalization. These results indicate that, after binding with receptors on the plasma membrane, GnRH is rapidly internalized, accumulating in secretory granules, and localizing over the nuclear membrane and later, in the nucleus. Association of radioactivity with secretory granules could be related to a specific action of GnRH at this level or to receptor recycling, and presence of label in the nucleus may be related to stimulation of neosynthesis of LH and GnRH receptors.
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  • 191
    ISSN: 1432-0878
    Keywords: Astrocytes ; Ependymal cells ; Circumventricular organs ; Tight junctions ; Orthogonal arrays of particles ; Freeze-fracturing ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ependymal cells in the ventricular wall and in several circumventricular organs of the rat were compared by means of freeze-fracturing. In principle, tight junctions and orthogonal arrays of particles (OAP) do not coexist in the cells bordering the ventricular wall: (1) Ordinary ependymal cells of the rat possess OAP and are devoid of tight junctions. (2) Epithelial cells of the rat choroid plexus are connected by tight junctions; OAP are lacking here. In some cases, however, tight junctions and OAP coexist in the same cell. In the boundary zone between choroid plexus and ependyma of the rat, the density of OAP is very low, whereas the tight junctions are well developed. In the subfornical and the subcommissural organ (SCO) of the rat both structures are poorly developed; in the SCO they occur segregated in different membranous areas. An overview of the literature confirms that tight junctions and OAP mostly exclude each other. The possibility that in astrocytes and ependymal cells tight junctions may have been replaced by OAP during phylogeny is briefly discussed.
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  • 192
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    Cell & tissue research 249 (1987), S. 443-449 
    ISSN: 1432-0878
    Keywords: Different strains ; Adrenal cortex ; Zonation ; Cellular composition ; Sex differences ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The zonation and cellular composition of the adrenal cortex of intact mature male and female rats of different strains (Chbb Thomm, CFY) and three strains of Wistar rats (W1, W2 and W3) at the age of 84–90 days were compared using morphometry. Both absolute and relative adrenal gland weights were higher in female than male rats. Rats of W3 and Chbb Thomm strains had the largest adrenals. These differences depended upon the higher volume of the zona fasciculata (ZF) and zona reticularis (ZR) in the W3 and Chbb Thomm strains than in the remaining animals. Females had larger adrenocortical zones than corresponding males. The average volume of the ZF cell ranged in males from 1589 μm3 (W1 strain) to 2111 μm3 (Chbb Thomm) and in females from 2249 μm3 (W1 strain) to 2894 μm3 (W3 strain). The average nuclear volume of the ZF cells was higher in female rats whereas there were no strain-and sex-differences in the size of zona glomerulosa (ZG) and ZR cells. The total number of parenchymal cells per pair of adrenals varied markedly among the studied strains, with the highest number in W3 and Chbb Thomm females. W3, Chbb Thomm and CFY females had larger number of parenchymal cells than males; the reverse was true for W1 strain whereas no differences were found among W2 male and female rats.
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  • 193
    ISSN: 1432-0878
    Keywords: Insulin-like growth factor I ; Somatomedin C ; Arterial injury ; Endothelial regeneration ; Intimai thickening ; Macrophages ; Smooth muscle cells ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present study the expression of insulin-like growth factor I (IGF-I; somatomedin C) immunoreactivity was examined in endothelial cells during repair after injury to the intima in the femoral artery of adult rats. Two types of injury were examined: (1) endothelial denudation induced by the use of a catheter, and (2) vessel compression by short-term ligation. In untreated rats, arterial endothelial cells showed no or, only infrequently, low IGF-I immunoreactivity in their cytoplasm. Endothelial cells at the border to the denuded area showed increased IGF-I immunoreactivity one day after injury to the intima of the femoral artery. Thrombocytes and fibrin deposits as well as vital endothelial cells, covered by clots, were immunonegative. The maximal intensity of IGF-I immunoreactivity was reached within 3 days after insult. The IGF-I immunoreactivity in the endothelial cells remained elevated for at least 4 weeks, compared to the controls. Intimai thickenings appeared within a week after injury and many cells in these thickenings showed intense IGF-I immunoreactivity as did the covering endothelial cells. Smooth muscle cells in the media were generally immunonegative during control conditions and after endothelial denudation. Spontaneously hypertensive rats (SHR) showed, similarly to their matched controls (WKY), approximately the same patterns of IGF-I immunoreactivity in their endothelial cells both under normal conditions and after injury. It is concluded that IGF-I is likely to be involved in the repair of the intima in injured arteries.
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  • 194
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    Cell & tissue research 250 (1987), S. 181-184 
    ISSN: 1432-0878
    Keywords: Prolactin cell ; Secretory granule ; Glycoconjugate ; Lectin ; Concanavalin A ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Prolactin granules in the anterior pituitary glands of male rats contain densely stained materials at the periphery of the matrix. These occur in both small spherical and large polymorphic types of granules. The presence of densely stained materials around secretory granules may be a useful criterion for identification of prolactin cells since the dense structure was observed in 95% of these cells after conventional staining by uranyl acetate and lead citrate. The localization of glycoconjugates in the prolactin granules was examined by applying concanavalin A (Con A) on the ultrathin sections. HRP-Con A or ferritinconjugated Con A bound specifically to the densely stained materials in the peripheral region of the prolactin granule matrix, indicating that this densely stained matrix contains glycoconjugates; the significance thereof is discussed with reference to the concentration and packaging of secretory product.
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  • 195
    ISSN: 1432-0878
    Keywords: Polypeptide 7B2 ; Adenohypophysis ; Secretion ; Immunocytochemistry ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary A highly conserved polypeptide termed “7B2”, isolated from human and porcine pituitaries, has been reported by immunoreactivity to be distributed in various organs. However, the highest concentration has been found in the pituitary as demonstrated by a specific radioimmunoassay. In order to determine the type of cells within the pituitary that contain 7B2 and to analyse its intracellular localization, specific immunocytochemistry techniques (unlabeled antibody, peroxidase-antiperoxidase) were used both for light and electron microscopy. Immunocytochemistry of both expiants and monolayer-cell cultures of the adenohypophysis was studied. Immunoreactivity to 7B2 has been found in 21.9% of the total number of cells. After simultaneous staining of serial sections with appropriate antibodies, 7B2 was found to be colocalized with β-LH/β-FSH in gonadotrophs and with β-TSH in thyrotrophs. In situ immunocytochemistry at the electron-microscopic level showed that immunoreactive 7B2 is compartmentalized within secretory granules. The small (130 to 250 nm) but not the large granules (400 to 700 nm) were labeled in gonadotroph-like cells and small granules (90 to 150 nm) were also labeled in thyrothrophlike cells. Study of the gonadotrophs in cell culture after Zamboni's fixation revealed weak to moderate immunoreaction in rough endoplasmic reticulum. The current findings as well as previous data indicate that 7B2 is synthesized, stored and possibly released from the adenohypophysis similarly to many other secretory products.
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