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  • 1980-1984
  • 1975-1979  (525)
  • 1920-1924
  • 1976  (525)
  • Cell & Developmental Biology  (502)
  • pharmacokinetics
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 9 (1976), S. 327-332 
    ISSN: 1432-1041
    Keywords: Antipyrine ; pharmacokinetics ; half-life ; blood ; plasma ; saliva ; individual variation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A previously described GLC method has been modified and applied to measurement of antipyrine levels in plasma, blood and saliva of man following administration of a single oral dose (10 mg/kg). The levels in blood and saliva were comparable to those in plasma at every time studied. The half life of antipyrine determined in blood, plasma or saliva in any given individual was similar. The intersubject variation in half-life was about two-fold (n=5). Antipyrine levels in saliva were not affected by the rate of saliva flow when collections were made continuously for 20 minutes. This study has demonstrated that kinetic data about antipyrine comparable to that from plasma may also be obtained from readily accessible tissue fluids, such as saliva and capillary blood.
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  • 2
    ISSN: 1432-1041
    Keywords: Chlorthalidone ; diuretics ; drug plasma concentration ; protein binding ; red blood-cell concentration ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A gas chromatographic method has been employed to determine chlorthalidone in plasma and whole blood after therapeutic doses. Radioactively labelled chlorthalidone was used for in vitro studies of the uptake of chlorthalidone from plasma by red blood cells. Chlorthalidone was markedly concentrated in red cells and as a compartment they would account for at least 30% of total drug in the body after multiple doses. The ratio between the plasma and red cell concentration of chlorthalidone varied between individuals. After a single oral dose of 50 mg in 6 healthy volunteers chlorthalidone was eliminated with a half-life of 51 to 89 hours. The apparent volume of distribution varied between 3 and 13 1/kg and the clearance between 53 and 145 ml/min. The mean steady-state plasma concentrations during treatment with a standard dose of 50 mg daily (n=10) varied 5-fold between individuals. During the steady state approximately 50% of the daily dose was excreted unchanged in the urine during 24 hrs. The plasma levels observed in patients were higher than those predicted from the single oral dose studies in healthy volunteers.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 9 (1976), S. 367-372 
    ISSN: 1432-1041
    Keywords: Sotalol ; β-adrenoceptor blocking drugs ; exercise tachycardia ; efficacy ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of sotalol after oral administration were measured on the tachycardia induced by strenuous exercise in normal subjects. Plasma sotalol levels were also determined. The oral administration of sotalol (50, 100, 200 and 400 mg) to 6 subjects produced a progressive reduction in the tachycardia induced by severe exercise. This was similar to the effects of 25, 50, 100, 200, 400 and 800 mg given to different subjects. Each increase in sotalol dose produced a successively greater reduction in exercise tachycardia. This did not appear to be maximum even with 800 mg. Oral sotalol was rapidly absorbed and produced peak blood levels in 2 – 3 hours. The plasma levels of sotalol measured 2 hours after the oral administration of 25 to 800 mg showed never more than a six-fold variation between different subjects. The half-life of sotalol in plasma was 12.7 ± SE 1.6 hours. There was a significant correlation between the logarithm of the plasma sotalol concentration and the percentage reduction of exercise heart rate. It is concluded that the oral administration of sotalol either once or twice daily (depending on dose level) will provide satisfactory 24-hour blockade of β-adrenoceptors.
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 9 (1976), S. 443-450 
    ISSN: 1432-1041
    Keywords: Cyclobarbital calcium ; pharmacokinetics ; plasma concentration ; relative bioavailability ; oral administration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and relative bioavailability of cyclobarbital calcium have been studied after oral administration of Phanodorm, of tablets according to the Formularium Nederlandse Apothekers (1968; FNA), and an aqueous solution. Six healthy volunteers participated in the investigation on three occasions and each received the three preparations. The dose administered was 300 mg cyclobarbital calcium. Plasma concentrations of cyclobarbital were determined at regular intervals. Absorption from the three preparations was rapid and was faster from the solution. Peak concentrations were usually attained within 1 h. The elimination of cyclobarbital could be described by a single first-order process with an average half-life of 11.6 h (range 8 – 17 h). There was little intra-subject variation of the half-life. Relative bioavailability for each volunteer was estimated by comparing the areas under the plasma concentration curves. The FNA-tablets and Phanodorm exhibited similar bioavailability, whereas the average bioavailability of the solution was 78% of that of FNA-tablets; the reason for this unexpected finding is unknown. It was concluded that cyclobarbital cannot be regarded as a uniformly suitable drug for the treatment of insomnia. The long half-life that was apparent in some of the volunteers (15 – 17 h) creates a substantial risk of residual effects on the following morning. In principle, however, the calcium salt of cyclobarbital may be used for induction of sleep, because of its rapid absorption.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 251-256 
    ISSN: 1432-1041
    Keywords: Sisomicin ; pharmacokinetics ; bioavailability ; two-compartment analysis ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics of sisomicin, a new single component aminoglycoside antibiotic related to gentamicin c1a, were determined in four healthy volunteers after intravenous and intramuscular administration of a 1 mg/kg dose. The elimination profile of this antibiotic follows two-compartment model kinetics after I.V. administration. The fast (α) and slow (β) disposition rate constants averaged 0.072 and 0.004 min−1, respectively. The volume of distribution at the steady-state averaged 0.185 liters/kg which approximately corresponds to the volume of extracellular space. The physiological availability of an intramuscular dose appeared to be complete. A method of administration adapted to the kinetic properties of the drug is proposed.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 311-317 
    ISSN: 1432-1041
    Keywords: Hydralazine ; instability of impaired renal function ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Following a single 50 mg dose of hydralazine (Apresoline®) in 13 patients with impaired renal function, a decrease in glomerular filtration rate (GFR) was correlated with an increase in serum half-life (T1/2) of the drug (r=−0.69; p〈0.01). The T1/2 was 15.8 h in one patient with a GFR of 16 ml·min−1, as compared to a T1/2 of 1.7–3.0 h found previously in 16 healthy volunteers. In 49 patients on long-term antihypertensive treatment with hydralazine, the ratio between the minimum steady-state drug concentration and the daily dose of hydralazine (C SS min : Dose) increased as the GFR decreased. This accumulation of the drug was particularly evident in patients with a GFR less than 30 ml·min−1 (r=−0.63; p〈0.01; n=19). As renal excretion of unchanged hydralazine is generally regarded as unimportant, the slower elimination rate in chronic renal failure was probably caused by a slower rate of metabolic conversion. It was found, however, that the renal excretion of hydralazine could easily have been underestimated, as only 12.7% of an initial hydralazine concentration of 200 ng·ml−1 in urine could be recovered after storage of the samples at room temperature for 24 h.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 325-330 
    ISSN: 1432-1041
    Keywords: Flutiorex ; pharmacokinetics ; sex ; anorectic agent ; sympathetic stimulation ; CNS stimulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The effects of flutiorex, a new anorectic agent, and of a placebo on food intake and the activity of the sympathetic and central nervous systems have been compared in a double blind trial in two groups of healthy volunteers, one of five males and the other of five females. Flutiorex 20 mg orally had a significant anorectic effect both in males and females, the observed reduction in food intake being 34.0 and 27.5%, respectively. It caused α-adrenergic stimulation (blood pressure and pupil diameter) and central nervous system excitation (critical flicker frequency), both of which were more marked in males than in females. Flutiorex was better tolerated by women than by men. Measurement of the blood level of flutiorex and its de-ethylated metabolite, norflutiorex, showed that both compounds were detectable in four of the five male subjects, but in only one of the five females. Sex-linked differences in the pharmacokinetics of flutiorex may explain the greater intensity of its effects in males.
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 343-347 
    ISSN: 1432-1041
    Keywords: Methaqualone ; hypnotic ; pharmacokinetics ; combination formulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Concentrations of methaqualone have been measured in the serum of five male human subjects receiving five consecutive evening doses of a combination formulation containing methaqualone (250 mg), carbromal (300 mg) and benactyzine (0.33 mg) in each tablet. After administration of the first dose, mean peak serum concentrations of methaqualone (1.2 µg/ml) occurred at 3 h. After obtaining peak levels, mean concentrations of methaqualone declined rapidly during the next 6 h and there-after more slowly during the next 18 h. After administration of the last (fifth) dose, mean peak serum concentrations of methaqualone (1.9 µg/ml; 1.5 µg/ml above the predose level) occurred at 2 h. After attaining peak levels, mean concentrations of methaqualone declined rapidly during the next 6 h, and thereafter more slowly, with a half-life of approximately 10 h. Mean concentrations of methaqualone in serum samples 24 h after the second, third, fourth or fifth doses were not significantly different (0.3 µg/ml – 0.6 µg/ml) during this period of dosing. This suggests that significant accumulation of methaqualone in the serum did not occur during a period of five consecutive evening doses of the combination formulation.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 257-262 
    ISSN: 1432-1041
    Keywords: Anti-inflammatory and analgesic drug ; indoprofen ; pharmacokinetics ; bioavailability ; man
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In a pharmacokinetic study of the new analgesic and anti-inflammatory drug indoprofen, plasma levels and urinary excretion were determined in four healthy volunteers after 100 mg and 200 mg iv, and after 100 mg (capsules) and 200 mg (tablets) oral doses. After iv administration, the mean biological half-life (t1/2 β) was about 2 h (range 1.4 to 3.2 h). The apparent volume of distribution Vdβ ranged between 11 to 17 % of body weight, indicating its limited extravascular distribution. Most of the drug was excreted in urine as glucuronide and a smaller proportion as unchanged indoprofen: the 24 h urinary excretion of these compounds accounted for 67 to 95 % of an iv dose. Peak plasma levels occurred between 30 and 120 minutes after oral administration of 100 mg as capsules or 200 mg as tablets. The mean biological half-life was about 2 h, as after iv administration. The bioavailability of oral doses was assessed using both plasma levels and urinary excretion data. The absorption of capsules and tablets was practically complete, that of the former being faster.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 25-29 
    ISSN: 1432-1041
    Keywords: Digoxin ; exchange transfusion ; pharmacokinetics ; neonates ; 86Rb assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary By means of an86Rb-uptake inhibition assay, changes in the plasma concentration of digoxin and the amount of the glycoside removed during exchange transfusion have been studied in two newborns. For comparison, the exchange procedure was simulated by a computer on the basis of a two-compartment open model and available pharmacokinetic constants. A rapid decrease in plasma digoxin concentration during exchange transfusion was found when the glycoside was administered intravenously or intramuscularly within 60 min before the procedure. The amount of digoxin removed by the exchange was less than 6 per cent of the given dose. Computer simulation of the procedure also showed removal of only a minor amount of digoxin. It is concluded that the decrease in plasma concentration and the removal of only a small amount of glycoside by the exchange transfusion can be attributed mainly to extensive tissue distribution of digoxin. The results imply that replacement of digoxin after an exchange transfusion seems unnecessary.
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  • 11
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 121-126 
    ISSN: 1432-1041
    Keywords: Diazepam ; pharmacokinetics ; subchronic dosage in man ; desmethyldiazepam
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary In seven healthy male volunteers the effects of the pattern of dosing on the pharmacokinetics of diazepam have been studied. A cross-over design was employed that consisted of three parts: a single intravenous dose (0.1 mg/kg), and oral dosing (10 mg/day) for six days followed by an intravenous bolus (0.1 mg/kg) on the seventh day, followed by re-examination of a single intravenous dose after diazepam (D) and its major metabolite desmethyldiazepam (DD) had been completely eliminated. Plasma levels of D and DD were monitored by a specific, sensitive GLC-method. In younger patients (n=5, age 29 – 35 years) the elimination half-life, T1/2 (β), of D was 33.9±10.6 h (mean±S.D.) after the single dose. The control study gave an almost identical result (35.7±12.1). After subchronic dosage in all patients T1/2 (β) showed a modest but significant prolongation (paired t-test p〈0.01) to 52.9±17.4 h. It was caused by a significant decrease (p=0.016) in total plasma clearance ( $$\overline {\user1{Cl}} $$ ), from 26.0±10.8 ml/min to 18.2±7.0 ml/min. Older patients (age 43–60 years) showed the same phenomenon. Blood/plasma ratios remained constant indicating no change in protein binding. Biliary excretion of D was measured in five patients with a T-tube. Only negligible amounts (0.3–0.4%) of administered D were excreted within 3 days after subchronic dosage, which demonstrates a lack of enterohepatic cycling of D. After multiple administration of D, there was accumulation of DD to levels approximately five times higher than after a single dose. The possibility that the slower elimination of D after subchronic treatment might be caused by DD was also supported by experiments in dogs and rabbits. After pretreating rabbits with DD and maintaining a high DD plasma level, there was prolongation of T1/2 (β) from 2.7 h to 5.2 h, with a corresponding decrease of $$\overline {\user1{Cl}} $$ from 101.6 ml/min to 23.4 ml/min. Similar results were obtained in dogs. It is concluded that the disposition of D is altered by subchronic use and may be regulated by the plasma DD concentration.
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  • 12
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 183-187 
    ISSN: 1432-1041
    Keywords: Hydralazine ; bioavailability ; pharmacogenetics ; first pass effect ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary After oral administration of a single 50 mg dose of hydralazine (Apresoline®), the serum half-life (T1/2) and bioavailability (AUC0−∞) were assessed in 16 healthy volunteers. The half-life was 2.57±0.14 h (S.E.) in 10 slow acetylators of sulphadimidine, and 2.18±0.15 h in 6 fast acetylators (difference not statistically significant). AUC0−∞ was significantly higher in slow acetylators, at 1.04±0.10 µg·hour·ml−1, compared to 0.66±0.12 µg·hour·ml−1 in the fast acetylators (p〈0.025). Treatment with Apresoline® 25 mg tid produced minimum serum concentrations at steady-state of 57.3±7.3 ng·ml−1 and 33.4±4.2 ng·ml−1 in 8 slow and 5 fast acetylators, respectively (p〈0.05). The corresponding maximum concentrations were 228.8±20.3 ng·ml−1 and 147.6±15.0 ng·ml−1 in slow and fast acetylators, respectively (p〈0.025). First-pass metabolism of hydralazine could explain the difference in bioavailability of the drug between fast and slow acetylators, without any corresponding difference in the elimination rate of the drug in the post-distributive phase.
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  • 13
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 337-341 
    ISSN: 1432-1041
    Keywords: Amitriptyline ; pharmacokinetics ; intravenous infusion ; two compartment model ; biological half-life
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary Amitriptyline was given to four male volunteers by constant rate intravenous infusion. Blood samples were collected before, during and at various times after the infusion for estimation of the serum concentrations of amitriptyline. The level of nortriptyline never reached a detectable level. A two compartment open model was shown to be applicable to the data obtained. The meaning of the parameters obtained by a non-linear, least squares curve fitting procedure is discussed and the values are compared to those recently published for nortriptyline. The calculated biological half-life of amitriptyline was about 17 hours, a figure which differs considerably from previously calculated values for volunteers, but is in accordance with some newer results from patients.
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  • 14
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 55-58 
    ISSN: 1432-1041
    Keywords: Penicillin V ; bioavailability ; pharmacokinetics ; dose ranging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary An absorption study was performed in ten healthy volunteers to test the bioavailability of various doses of two penicillin V-K preparations: Isocillin® (Hoechst AG, Federal Republic of Germany), — tablets of 600 000 and 1.2 Mega U; V-Cillin® (Eli Lilly, USA), — tablets of 200 000, 400 000 and 800 000 U. The serum concentrations and elimination of the active substance in urine were measured for six hours after administration. Independently of the source of the preparation, a strict linear relation between the dose and the area under the serum curve (AUC), or between the dose and the urinary elimination, was demonstrated by regression analysis. The dose-dependent increase in the AUC was highly significant (p〈0.01) in the range tested, i.e. between 200 000 and 1.2 Mega U. The relative elimination of active substance in urine lay within narrow limits for all doses (35.7–41.3%). Thus, both compounds proved to have the same bioavailability.
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  • 15
    ISSN: 1432-1041
    Keywords: Ampicillin ; bioavailability ; pharmacokinetics ; branded products ; proprietary preparations ; capsule formulation ; tablet formulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The pharmacokinetics and bioavailability of three different brands of ampicillin were studied in 10 volunteers. After intravenous administration ampicillin can be described adequately by a two-compartment open pharmacokinetic model. The half-life during the α-phase was 9 min and the β-half-life was in the range 50–60 min, independent of the mode of administration. Absolute bioavailability was determined from the ratio of the areas under the serum concentration curves obtained after oral and intravenous administration of equal doses. Bioavailability was also estimated by analysis of variance. The results indicated absolute availability of the three products of 39–54%. One of the products, a capsule formulation, showed a significantly lower bioavailability than the others, which were tablet formulations.
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  • 16
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 263-271 
    ISSN: 1432-1041
    Keywords: Butobarbital ; pharmacokinetics ; plasma concentration ; oral administration ; accumulation ; enzyme induction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A method is described for the assay of therapeutic levels of butobarbital (5-ethyl-5-n-butylbarbituric acid) in human plasma, which involves a single extraction step followed by gas chromatography with alkali flame ionization detection. The pharmacokinetics of butobarbital were studied in five healthy volunteers after oral administration of 200 mg. Plasma concentrations were determined at regular intervals up to 96 h and the data were fitted by non-linear, least squares regression analysis according to one-compartment kinetics. The average lag time was 0.11 h and the absorption half-life 0.21 h. The elimination half-life varied from 33.6 to 41.5 h with an average of 37.5 h. Four of the volunteers participated in a study of multiple dosing (every 24 h) during which substantial accumulation of butobarbital was observed. The elimination half-life after termination of drug administration had decreased to about 20–25% of its initial value, probably because of enzyme induction. It was concluded that butobarbital could not be regarded as a suitable drug for treatment of insomnia, since CNS depressant effects were likely to persist into the following day. Repeated administration of butobarbital should be avoided and its incidental use restricted to patients who require day-time sedation.
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  • 17
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 293-295 
    ISSN: 1432-1041
    Keywords: Bendroflumethiazide ; diuretics ; GLC ; thiazides ; plasma level ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary A GLC method for determination of bendroflumethiazide has been developed, using extractive methylation. Cyclopenthiazide was used as internal standard. The maximal plasma concentration (56–107 ng/ml) after bendroflumethiazide 10 mg given orally to four healthy volunteers was seen at 2–2.5 h. On the slope between 4 and 10 h T1/2 averaged 2.7 h.
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  • 18
    ISSN: 1432-1041
    Keywords: Diabetes mellitus ; drug interaction ; phenprocoumon ; pharmacokinetics ; pharmacodynamics ; sulphonylureas
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The influence of various antidiabetic treatments on the kinetics and efficacy of a single oral dose of 12 mg phenprocoumon were studied in 71 hospitalized patients, 58 with adult-onset diabetes mellitus and 13 non-diabetic aged patients, and 13 healthy young volunteers. Treatment for one week or longer with insulin or the antidiabetic sulphonylureas tolbutamide, glibenclamide or glibornuride, altered neither the plasma level (1.29 – 1.40 µg/ml at zero time) nor the half-life of phenprocoumon (5.2 – 6.8 d) compared to treatment by diet alone. The mean half-life of phenprocoumon was significantly shorter in non-diabetic aged patients (4.2 d) than in diabetic patients of the same age (5.1 – 6.8 d), or in young healthy volunteers (5.7 d). The efficacy of a single dose of phenprocoumon (maximal reduction of Quick-values by 34 – 47% after 48 to 72 hrs) in diabetic patients treated with diet, or diet and antidiabetic drugs, was the same as in non-diabetic aged patients. In healthy young volunteers phenprocoumon was half as effective as in aged patients.
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  • 19
    Electronic Resource
    Electronic Resource
    Springer
    European journal of clinical pharmacology 10 (1976), S. 63-68 
    ISSN: 1432-1041
    Keywords: Phenazone ; pharmacokinetics ; injuries ; surgery ; operation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The elimination rate of phenazone after a single oral dose has been studied before and after elective operations. In a group of patients with different illnesses the elimination rate was increased on the fourth to seventh days after operation but was unchanged on the second and third days. The change in elimination rate was highly significant in a standardized group of nine patients with a ligament injury in one knee studied on the fourth or fifth postoperative day. Possible reasons for the changes are discussed.
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  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Journal of pharmacokinetics and pharmacodynamics 4 (1976), S. 199-230 
    ISSN: 1573-8744
    Keywords: disopyramide ; antiarrhythmic ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The pharmacokinetics of the antiarrhythmic disopyramide, 4-diisopropylamino-2-phenyl-2-(2-pyridyl)butyramide phosphate, and its monodealkylated metabolite were investigated in seven volunteers after intravenous (1 and 2 mg/kg) and oral (3 and 6 mg/kg) administration. Unchanged drug (52%) and the monodealkylated metabolite (25%) were renally excreted on intravenous administration. The pharmacokinetics of disopyramide were first order and dose independent only when referenced to the drug not bound to plasma proteins since this binding was dose dependent. The apparent half-lives of the α and β phases on intravenous administration were 2 min and 4.5 hr, respectively. The apparent volumes of distribution of the central and peripheral compartments, referenced to unbound disopyramide in the plasma, were 9 and 80 liters, respectively. The half-life of absorption of oral aqueous disopyramide phosphate was 30 min with a lag time of 16 min and an apparent first-pass metabolism of 16% of the absorbed dose, consistent with the hepatic efficiency of 14%. The renal and metabolic clearances were 125 and 111 ml/min, respectively. Graphical and computer analysis of the plasma and urine data showed dose-independent first-order pharmacokinetics of plasma unbound drug in a two-compartment-body model to give two metabolites and a first-pass transformation of a fraction of the oral dose. The absorption efficiency of unchanged drug was 83%.
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  • 21
    Electronic Resource
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    Springer
    Journal of pharmacokinetics and pharmacodynamics 4 (1976), S. 337-353 
    ISSN: 1573-8744
    Keywords: bioavailability ; pharmacological data ; pharmacokinetics ; modeling
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The use of data deriving from monitoring the time variation of the intensity of pharmacological effect(s) following dosing can often present an advantageous alternative to the more conventional approach of using chemical or radiological assay of blood and/or urine level data for bioavailability evaluations of drug products: bioavailability studies can be performed with drugs where no assay exists. A relatively simplified discussion of the general theoretical principles on which the use of pharmacological data is based and a stepwise description of the approach for its routine application in bioavailability studies are presented. Approaches for computing rates and extents of drug bioavailability vs. time profiles on analog and digital computers are qualitatively described and quantitatively presented in a subsequent report. The concept of preabsorption (gastrointestinal bioavailability) is introduced and biophasic availability of drugs to local sites of action is discussed.
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  • 22
    Electronic Resource
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    Springer
    Journal of pharmacokinetics and pharmacodynamics 4 (1976), S. 355-375 
    ISSN: 1573-8744
    Keywords: deconvolution ; bioavailability ; pharmacokinetics ; modeling ; pharmacological data
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Mathematical expressions and approaches to the computation of rates and extents of drug bioavailability for implementation on analog and digital computers are derived. The equivalency of expressions derived on the basis of assuming compartment models to an approach based on using experimentally determined weighting functions is demonstrated. The relative merits of the two techniques are discussed: their application for use with temporal pharmacological data is emphasized. The applicability of the computational techniques to determining the availability of drugs at local sites of action (biophasic availability) and to computing preabsorptive drug release into the gastrointestinal contents (gastrointestinal bioavailability) is pointed out. An approach to computationally predicting in vivo blood level or pharmacological response vs. time profiles from in vitro dissolution testing results is presented and its limitations are discussed.
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  • 23
    ISSN: 1573-8744
    Keywords: pharmacokinetics ; compartmental model ; phenol red ; phenol red glucuronide ; dogfish (Squalus acanthias)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A flow-limited multicompartment model simulates the distribution and disposition of phenol red in the dogfish after intravenous administration. Glucuronide conjugate, as well as parent compound, was found in urine and bile, but not in plasma, kidney, or liver tissue. An apparent 4-hr lag in phenol red appearance in the gall bladder was simulated using two stirred tanks connected in series to represent the bile ducts. The model should facilitate use of the dogfish in pharmacokinetic studies of drugs, environmental contaminants, and other xenobiotics.
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  • 24
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    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 150 (1976), S. 19-58 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A thin, compressible, lateral suture and ventral plate overlap permit limited movement of the thick and rigid dorsal and ventral plates of Fuscouropoda agitans. Seven pairs of large dermal glands debouch onto the surface. Trochanteral rotation permits defensive leg adpresion and an insectan type of ambulation. The complex hypopharynx-pedipalpal-coxae has a buccal and cheliceral cavity separated by an atriculated epipharynx. The pharynx is Y-shaped in cross section. Extensive paired salivary glands lie above the very long and dexterous 3-segmented chelicerae, and a large pair of coxal glands debouch on coxae 1. From four blunt-ended tracheae, bundles of unbranching tracheoles extend in specific tracts to all organs. The ventriculus is small with three pairs of large caeca; a tightly packed single layer of digestive cells individually enlarged to absorb-phagocytize and digest the food. A typical mesostigmatid excretory tube is present. A typical acarine synganglion is present; mixed nerves have a basal swelling. A postulated neurosecretory organ arises from the pedipalpal nerve. The oocytes enlarge within funicular stalks from the walls of the small median ovary. A large spermatophore is stored in the seminal vesicle; fertilization occurs during oviposition. A tension hinge partially opens both male and female genital plates; closure effected by muscles acting on very long genital plate apodemes. Within sequentially produced spermatogonial cysts of the testes, meiosis is completely synchronous. A large, multilobed male accessory gland produces a large volume of seminal fluid; a mixture of at least four secretions. The origins and msertions of the body wall, genital organ, digestive tract, mouthpart and leg muscles are listed and illustrated. A comparison of anactinotrichid and actinotrichid mites indicates fundamental and consistent morphological differences in aspects of the cuticle, leg articulations, digestive system, excretory system, reproductive system and coxal glands.
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  • 25
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    Journal of Morphology 150 (1976), S. 279-297 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: An investigation of the structure of the iridescent scales of the green hairstreak, Callophrys rubi, reveals an internal lattice which is probably cubic close-packed in form. We present a model which explains the formation of the lattice in terms of packing of spheres and surface tension forces and generalize these results to internal structures in other Lepidopteran scales.
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  • 26
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: There are 36 to 42 taste bristles on each half of the labellum of Drosophila melanogaster; most of them are two-pronged with a pouch between them. Some end bluntly with a pore at the tip.Each taste-bristle has two lumina: one is circular, the other crescent-like in cross section. In most bristles four dendrites of chemoreceptor neurons run along the circular lumen. In five to seven taste-bristles only two chemoreceptor neurons are found. A mechanoreceptor neuron sends a dendrite to the base of each taste-bristle.The dendrites are surrounded by four concentrically-arranged sheath cells. The inner cell secretes the cuticular sheath; cells II and III are presumably two trichogens, one secreting the bristle material around the circular lumen, the other around the crescent-like lumen. Cell IV, especially rich in bundles of microtubules, secretes the cuticle of the socket, and corresponds to the tormogen. The neurons have the typical structure found in insect sensilla. In many sensilla one neuron is less electron-dense than the others and may be the water-sensor.On the medial side of the labellum between the pseudotracheae are rows of taste pegs covered by folds. In each peg one chemoreceptor and one mechanoreceptor are found.The number of axons in each labial nerve agrees with the total number of dendrites in all taste organs of each lobe.
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  • 27
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    Journal of Morphology 150 (1976) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 28
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    Journal of Morphology 150 (1976), S. 423-451 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Stichopus moebii, a sea cucumber, has a closed circulatory system which is unique in its degree of development for the phylum Echinodermata. The gross anatomy, histology and fine structure of the system were studied. Blood vessels consist of a coelomic surface of ciliated epithelium, a layer of muscle and nerve cells, followed by connective tissue and luminal lining of endothelium. Basically the blood vascular system consists of two major vessels running parallel to the gut: the dorsal vessel pumps colorless blood via the vessels within the walls of the intestine into the ventral vessel. There are two specialized areas of the circulation: (1) At the upper small intestine 120 to 150 muscular single-chambered hearts pump blood from the dorsal vessel into a series of intestinal plates. (2) At the lower region of the small intestine the vasculature is associated with the left respiratory tree. Blood passing from the dorsal pulmonary vessel can take two routes to the gut, it either passes through myriads of minute respiratory shunt vessels entangled with the respiratory tree or it passes through a unique follicle network consisting of tiny channels periodically dilated into chambers filled with iron deposits, necrotic cells and developing coelomocytes.
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  • 29
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    Journal of Morphology 150 (1976), S. 639-679 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Anatomical components of afferent innervation in the rim of the octopus sucker are described. In the sensory epithelium under the smooth cuticle two associated ciliated receptor cell-types (presumably chemosensitive) occur in clusters. A third ciliated receptor cell-type under the toothed cuticle may be a mechanoreceptor. A non-ciliated receptor cell-type of unknown function, under the toothed cuticle, is characterized by a microvillus-lined apical canal containing dense granular material. The axons of the latter two receptors go directly into large nerve tracts which nm through the infundibular muscle and on to the ganglion of the sucker. The axons of the first cell-types terminate on interneurons either in the base of the epithelium or below the epithelium. All the interneurons of the basal region of the epithelium migrate centripetally and develop into encapsulated interneurons. Within the epithelium, fine fibers provide collateral contact among cluster receptors. Collateral interaction among basal and encapsulated interneurons occur in the infundibular plexus. The microanatomy of the rim of the sucker suggests that chemosensory cues are funneled into the interneurons where they are concentrated into integrated signals, while other sensory input is probably sent directly to the ganglia of the sucker and/or arm.
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  • 30
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    Journal of Morphology 150 (1976), S. 727-761 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pyloric region of Eosentomon and Acerentomon (Insecta, Protura) is described. In both species the posterior cells of the midgut carry short microvilli. Beneath the epithelial cells there is a muscular pyloric sphincter for closing the intestinal lumen. Behind the sphincter is a wide pyloric chamber lined by cells with very long microvilli which point anteriorly toward the midgut. These cells regulate the passage of the intestinal contents into the hindgut. Secretions from the Malpighian papillae are emitted into the gut at this level. In Eosentomon three regions (R1, R2 and R3) are visible in the Malpighian papillae, whereas in Acerentomon region R1 is lacking. The R1 region contains secretory cells with elaborate glycoprotein-containing granules. The R2 region is composed of cells somewhat resembling the secretory cells of Malpighian tubules of insects. Presumably R1 and R2 cells emit secretions into the central cavity of each papilla. Cells of R3 form a duct for the secretion. It is suggested that the R2 region represents a basic excretory region, common to Protura, whereas the R1 region, in Eosentomon, may be a specialized area performing supplementary excretory functions.
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  • 31
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    Journal of Morphology 150 (1976), S. 785-803 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This manuscript describes in precise detail the ultrastructural alterations produced as a result of laser microirradiation of nucleoli and nucleoplasm of tissue culture cells. Because of the general difficulty of single cell recovery, flat embedding, and serial sectioning, very few studies have ever been conducted on microbeam irradiated cells; yet the use of the microbeam technique has become widespread in functional studies of the nucleus. The results presented here demonstrate two classes of lesion material: small spherical electron dense bodies 0.05-0.02 μm in diameter and a larger, more irregular electron dense material up to 1 μm in length. The occurrence of these different types of lesion materials is described in control irradiated nucleoli and nucleoplasm, irradiated nucleoli and nucleoplasm in quinacrine treated cells, irradiated nucleoli and nucleoplasm in actinomycin D treated cells, and irradiated nucleoli and nucleoplasm in combined actinomycin D and quinacrine treated cells. In all the cells in which actinomycin D was employed, nucleoli were selectively irradiated in either their granular or fibrillar zones. The results of the ultrastructural studies are discussed in light of earlier functional studies.
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  • 32
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    Journal of Morphology 150 (1976), S. 843-859 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The general form and adaptation of the digastric muscle in carnivores are reviewed and discussed. The digastric muscle differs from the general plan in certain aquatic carnivores and felids. In the pertinent aquatic species the muscle is enlarged. The observations suggest that the enlargement is an adaptation for rapidly opening the jaws against the resistance of water. In felids, the insertion of the muscle is much farther forward than in most other carnivores. The observations suggest that the development of short jaws in felids necessitated a compensatory anterior relocation of the digastric insertion in order to preserve the ability to achieve a large gape.
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  • 33
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    Journal of Morphology 150 (1976), S. 889-899 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Homolid crabs (Hypsophrys) from water deeper than 700 m in the Straits of Florida and Arabian Sea have smooth darkened oval spots contrasting with the surrounding roughened integument on inner and outer surfaces of each pincer at the base of the fixed finger. Cuticle is thinner over these spots than over surrounaing tissues. Beneath each spot is an organ composed of two markedly contrasting layers of tissue: (1) an outer, densely staining layer of tightly packed tubules, relatively straight and perpendicular to the overlying surface proximally but progressively convoluted and narrowed distally, finally ending blindly in association with the overlying thinned cuticle; (2) an inner layer of relatively large, eosinophilic, irregular cells with dark nuclei also trending at a right angle to the integument and bulging into the hemal sinus of the hand but separated from it by an epidermal lining. Droplets secreted from the inner layer apparently move into and along the tubules. Similar organs are known in no other crabs. The function is unknown but the structure suggests that they may be photophores.
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  • 34
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    Journal of Morphology 150 (1976), S. 763-783 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of a well studied insect chemosensory unit is presented in this report. Two separate lumina are present in this chemosensory unit, the trichogen and sensillar lumina. The fluid within the trichogen lumen exclusively bathes the dendritic terminals, and may be involved with the reception and/or modulation of environmental stimuli. Cytoplasmic extensions of the trichogen cell which line the trichogen lumen may be involved in the production of the cuticular sheath. The sensillar lumen is bordered by the tormogen and a sleeve cell, and is continuous with the unoccupied channel of the setal shaft. Functions for the various cellular components of the blowfly chemoreceptor sensillum are offered.
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  • 35
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This study indicates that eggs containing calcium carbonate crystals occur in at least 36 of the 65 known families of the land snails (class Gastropoda: order Stylommatophora). Eggs from 22 of these families were available for examination. The x-ray diffraction data, available for the first time for 21 of these families, shows that these egg shells are all made of calcite only, or of a combination of calcite with smaller amounts of aragonite. All of the snail (body) shells examined were made of aragonite only. This is the first ultrastructural investigation of these egg shells, and it indicates that the eggs exhibit enough structural diversity to allow identification of parental animals to genus, and often to species level solely on the basis of egg shell ultrastructure.All of the calcified eggs may be divided into two groups: (1) partly calcified, with discrete crystals of CaCo3 dispersed in the jelly layer, and (2) heavily calcified, with a hard, brittle egg shell made of fused crystals of CaCO3 much like an avian egg. Both types of calcified eggs occur in oviparous as well as in ovoviviparous snails. Because of the wide distribution of calcified eggs in the Stylommatophora, and because of the occurrence of heavily calcified eggs in ancient families such as Partulidae, Endodontidae, and Zonitidae, the calcified egg is viewed as a primitive land snail trait associated with terrestrial adaptation. The function of the calcified egg shell, in addition to mechanical support of egg contents, is to supply the developing embryo with enough calcium to form the embryonic shell by the time of hatching.
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  • 36
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    Journal of Morphology 148 (1976), S. 23-31 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When cervical segments 14 to 15 of the chicken spinal cord are cut transversely and studied by routine histological and histochemical methods, an onion-shaped region, filled with thread-like fibers, if seen to surround the ependymal cells of the central canal and to be bounded laterally by the neural elements of the spinal gray matter. This area is negative for succinic dehydrogenase, beta-hydroxybutyrate dehydrogenase and cholinesterase activity, but very strongly periodic acid-Schiff positive. Diastase controls show the positive material to be glycogen. Parasagittal sections through this cervical region and into the upper thoracic cord, show the glycogen-rich region to extend longitudinally throughout the region. Because of its location and histochemical characterization, which, He similar to that of the ventral portion of the glycogen body, the term brachial glycogen budy is proposed for this structure.
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  • 37
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    Journal of Morphology 148 (1976), S. 1-21 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Anterior dorsal ventricular ridge (ADVR) is a major subcortical; telencephalic nucleus in snakes, Its structure was studied in Nissl, Golgi, and electron microscopic lrerarations in several species of snakes. Neurons in ADVR form a homogeneous population. They have large nuclei, scattered cisternae of rough endoplasmic reticulum in their cytoplasm, and bear dendrites from all portions of their somata. The dendrites have a moderate covering of pedunculated spines. Clusters of two to five cells with touching somata can be seen in Nissl, Golgi, and electron microscopic preparations. The area of apposition may contain a series of specialized junctions which resemble gap junctions. Three populations of axons can be identified in rapid Golgi preparations of snake ADVR. Type 1 axons course from the lateral forebrain bundle and bear small varicosities about 1 μ long. Type 2 axons arise from ADVR neurons and bear large varicosities about 5 μ. long. The origin of the very thin type 3 axons is not known; they bear small varicosities about 1 μ. long. The majority of axon terminals in ADVR are small (1 μ. to 2 μ long), contain round synaptic vesicles, and form asymmetric active zones. This type of axon terminates on dendritic spines and shafts and on somata. A small percentage of terminals are large, 5 μ in length, contain round synaptic vesicles, and form asymmetric active zones. This type of axon terminates only on dendritic spines. A small percentage of terminals are small, contain pleomorphic synaptic vesicles, and form symmetric active zones. This type of axon terminates on dendritic shafts and on somata.
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  • 38
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    Journal of Morphology 148 (1976), S. 33-63 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tooth development and replacement in fetal and adult viviparous caecilians (Amphibia: Gymnophiona) are described and analyzed according to current theories of tooth succession. The fetal dentition differs from that of the adult in morphology, position, and function. Teeth are used by fetuses to scrape the oviducal epithelium, thus stimulating the secretion of a nutrient substance. Fetal dentitions vary in morphology and position in different species. The ontogeny of teeth of several species is described and the patterns of addition of loci and of replacement are analyzed, Loci are added both posteriorly along the jaw and between existing loci as the jaw grows prior to ossification; subsequently addition is restricted to the posterior part of the jaw. Tooth replacement is alternate. The several rows and patches of teeth are the result of retention of replacement series on the dentigerous elements. Tooth development and replacement in a series of juveniles and adults of different sizes in a single species are also considered. Post-fetal patterns of development and replacement are similar to those seen in larvae and adults of oviparous species. Variation in numbers of teeth and proportions of teeth at particular stages occurs ontogenetically and among individuals of the same size, though proportions occur in a similar pattern throughout the series. The general pattern of tooth replacement in fetuses and adults can be explained by either Edmund's Zahnreihen theory or by Osborn's Tooth Family theory, but replacement in fetal tooth patches and the fetal-adult dentitional transition are explained by neither.
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  • 39
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    Journal of Morphology 148 (1976) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 40
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    Journal of Morphology 148 (1976), S. 65-87 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In Brallchiobdella pentodonta Whitman meiosis begins in follicles containing 16 spermatogonia. In each follicle the spermatogonia are connected by cytoplasmic bridges to a central anuclear cytoplasmic mass or cytophorus. They develop synchronously. Synaptonemal complexes are present in the primary spermatocytes. Spermatids contain a large globoid paranuclear body consisting of an acrosomal granule and coiled tubules which evidently receive the contents of the acrosomal granule and are considered the acrosome carrier. The spermatids separate from the cytophorus only when differentiation is completed.The ripe spermatozoon is relatively long. It has anteriorly the coiled tubules, followed by the nucleus, the mitochondrial sphere and the distal centriole from which the flagellum originates, A coiled ribbon-like structure encloses the flagellum along its entire length while a manchette of microtubules surrounds all the other structures of the sperm.
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  • 41
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    Journal of Morphology 148 (1976), S. 89-135 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The muscles and bones of the pectoral fin of Serrasalmus nattereri, the piranha, resemble those of generalized, lower teleosts with specializations related to a body shape adapted for high-speed carnivory; the pectoral fins being highly mobile with strong ligaments to the rays. The presence of two occipital nerves appears primitive, while the emergence of the subclavian artery within the branchial cavity, as in Gasteropelecus sternicla, appears specialized. The muscles and bones of the latter fish, a fresh-water flying fish, are specialized for self-propelled, aerial flight in the fusion of the right and left girdles greatly expanded for insertions of complex appendicular (flight) muscles, and in the consolidation of the rays and radials into one functional unit moving vertically in flight though contraction of vertical, massive ventral flight muscles. The bony pectoral anatomy of Electrophorus electricus, the electric eel, is specialized in having a mobile joint between the primary girdle and the cleithrum, the former being suspended vertically from the cleithrum by ligaments. The proximal radials and rays are very numerous and vertically aligned. The cleithrum is shaped to accommodate the extensive sternohyoid and pharyngocleithral muscles. The sheet-like appendicular muscles extend beyond the special joint and control its movement. The deeper muscles do not cross this joint. The arterial system is specialized in lacking a deep brachial artery.
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  • 42
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    Journal of Morphology 149 (1976), S. 1-31 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The cibarial food pumps of aquatic Heteroptera contain specialized epipharyngeal triturating devices. In the Naucoridae, striated bands and transverse plates triturate particles against the underlying hypopharynx. Anterior to them lie a pair of oblique folds which play an accessory role. The gross morphology of these devices is very similar in representatives of five genera of typical Naucoridae (Ambrysus, Pelocoris, Limnocoris, Cataractocoris, Cryphocricos) and differs from that of the atypical genus Aphelocheirus.The scanning electron microscope reveals additional differences between Aphelocheirus and the typical genera as well as variations, among the latter, which are not visible with the stereoscopic microscope. The oblique folds of the typical Naucoridae are well developed and contain processes for trapping particles; in three genera the region posterior to the folds is also modified. In Aphelocheirus only the latter region appears to trap particles, and the oblique folds are smooth and weakly developed. The striated bands of all genera bear ventral ridges arranged into transverse zones with precise patterns. The fourzoned bands of Aphelocheirus have a very different pattern than the two-zoned bands of the other genera. Among the latter, Cryphocricos has a simpler pattern of ridges than the other typical Naucoridae. The ventral surfaces of the transverse plates are highly modified in Aphelocheirus and less so in the other genera; those of Cryphocricos differ from those of the other Naucoridae.The fine structure of the cibarial epipharynx supports the views of some systematists that (1) Aphelocheirus should be placed in the monogeneric Family Aphelocheiridae rather than in the Naucoridae, (2) Cryphocricos represents a different subfamily than the other four typical Naucoridae, and (3) Cataractocoris belongs in the same subfamily as Ambrysus rather than with Cfyphocricos.
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  • 43
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    Journal of Morphology 149 (1976), S. 53-71 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Appearance of collagen fibrils in the cuticle was seen by electron microscopy to be preceded by fonnation of a finely filamentous matrix material. At first, the fine filaments of the matrix are unorganized. However, signs of orthogonal ordering soon appear in the most superficial portion of the cuticle, and subsequently appear more basally and closer to the underlying epidermis. Meanwhile, fibrils of different staining properties and identifiable as collagen begin to be deposited in the superficial portion of the cuticle, the same region which first showed organized fine filaments. Then, like the fine filaments before them, the collagen fibrils polymerize more basally. Collagen appears to polymerize on the preformed skeleton of fine filaments as though the fine filaments caused the collagen to assemble. Neither the polymerization nor ordering of collagen fibrils seems to require direct cellular intervention but occur first in that portion of the cuticle which is furthest away from the underlying epidermis. The fine filaments may be self ordering, extracellular macromolecules which in turn determine the polymerization of collagen fibrils.
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  • 44
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    Journal of Morphology 149 (1976) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 45
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    Journal of Morphology 149 (1976), S. 265-277 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oogenesis of the fresh-water triclad Dugesia dorotocephala has been studied by electron microscopical methods, with particular regard to the genesis and composition of the so-called “Balbiani body.” Its origin is clearly recognizable in young oocytes where the few mitochondria present seem to gather at the level of the perinuclear ooplasm. Here they surround dense masses of finely granular, fibrillar material probably coming from the nucleus. During the previtelloge ic period, mitochondria rapidly increase in number while the dense masses progressively dissolve.In the vitellogenic oocytes the Balbiani body shows its final configuration: it appears as a large area (up to 15-20 pm in diameter) consisting of innumerable densely packed mitochondria, some smooth vesicles and free ribosomes. This aggregate of cytoplasmic organelles remains unmodified in the mature oocytes.The function of the “Balbiani body” of D. dorotocephala is as yet unclear; it can only be asserted that it is not correlated with yolk production in which the endoplasmic reticulum and the Golgi complex are involved.
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  • 46
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    Journal of Morphology 149 (1976), S. 421-435 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Whole ovaries from 16-day fetal mice were cultured for 6 to 20 days and then transplanted to the kidneys of ovariectomized adult mice where they remained for one to four weeks. After three weeks in the host's kidneys, many follicles developed within the transplants and became vesiculated. Many of the oocytes within these follicles had formed the first metaphase spindle of meiosis and several had completed the first polar body. Host mice bearing transplants that contained vesiculated follicles showed uterine stimulation and keratinization of their vaginae. However, ovaries that had been in culture for more than ten days before transplantation showed a limited response to the gonadotropins and never matured sufficiently to stimulate the host's reproductive tract. No ovulations occurred in any of the transplants.
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The infracerebral gland of Nereis is made up of three types of cells. C1 cells are hypertrophied pericapsular elements, whereas C2 and C3 cells have the morphological and cytological features of neurosecretory neurons. C2 and C3 cells give rise to centripetal “proximal processes” which extend into the brain through the midventral pocket formed by delamination of the brain capsule. Their “distal processes” terminate within the gland or its immediate vicinity. “Centrifugal fibers” arise from nerve cells located within the brain and appear to synapse upon the proximal processes of C2 cells in the region of the midventral pocket and in the ventral region of the brain. The cytology of C2 and C3 cells suggests that they are the source of distinct peptide hormones.
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  • 48
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    Journal of Morphology 150 (1976), S. 321-326 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Exercise affects the growth of the dorsal longitudinal flight muscles in the tsetse fly. Examination of electron micrographs of flight muscles taken from flies subjected to enforced exercise, “ormal” exercise and no exercise reveals that both mitochondrial and myofibrillar fractions of the muscles are stimulated to grow at a faster rate by enforced exercise but that the mitochondria respond more rapidly.
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  • 49
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ultrastructure and shell formation in the testaceous ameba, Lesquereusia spiralis, were investigated with both scanning and transmission electron microscopy and X-ray microanalysis. The nucleus, surrounded by a fibrous lamina, contains multiple nucleoli. The cytoplasm, containing a well developed granular endoplasmic reticulum, also contains remnants of starch granules in stages of digestion. Spherical aggregates of ribosome-like particles may be seen. Golgi complexes seem to produce both a nonordered fibrous material and an electron dense vesicle. Only the latter appears to bleb off from the Golgi complex. X-ray microanalysis demonstration of silicon in Golgi vesicles and in some dense vesicles suggests that the fibrous component of the cisternae may take up and concentrate silica to form the electron-dense component of the vesicles. Membrane-bound siliceous crystals are often seen adjacent to the Golgi, suggesting either a Golgi origin or platelet formation in vesicles after release from the Golgi complex. Both electron-dense bodies and siliceous platelets are released from the cell by a process similar to apocrine secretion and may be seen outside the cell in route to the shell during shell morphogenesis. Shell development involves fusion of electron-dense bodies to form a matrix, positioning of siliceous platelets in this matrix parallel to the shell surface, and development of a system of matrix chambers. A particulate glycoconjugate is released to the shell surface upon rupture of the matrix chamber.
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  • 50
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    Journal of Morphology 150 (1976), S. 359-368 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Stereological analysis of the ultrastructural composition of the pulmonary alveolo-capillary region of mice living at sea level compared with that of the same species (Phyllotis darwini) genetically adapted to life at 4,660 m reveals a trend at high altitude towards a greater volume percentage of tissue components. On a weight-specific basis, non-circulating tissue occupies a significantly greater volume in high-altitude mice, but air space and capillary contents are not correspondingly greater. Since the arithmetic mean thickness of the tissue layers and of the air-blood barrier are the same in the two altitudinal groups, the average alveolus must have a smaller volume in the high-altitude mice.Epithelial, endothelial, and erythrocyte surface areas per gram body weight are significantly greater in the high-altitude mice.Nuclear counts indicate that the larger lungs of mice adapted to high altitude are due to larger Pneumocyte I and II and endothelial cells rather than to an increase in the number of these cells. Hematocrits measured within the pulmonary capillaries in the two altitudinal groups were equal.An heretofore unrecognized feature of possible adaptive value is the surface/volume ratio of erythrocytes, which is similar for erythrocytes in alveolar space of mice at low and high altitudes but within lung capillaries is 14.7% greater at high altitude.
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  • 51
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    Journal of Morphology 150 (1976), S. 299-305 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The neck region of the mature spermatozoon of Discus rotundatus is described. No evidence for a centriole or centriolar derivative is obtained. Nine striated coarse fibres and the two central fibres of the axoneme extend into the base of the implantation fossa. The axonemal doublet system is disrupted in the neck region. There are two fibrous accessory structures located between the central doublet and the striated coarse fibres.
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  • 52
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    Journal of Morphology 150 (1976), S. 307-319 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Explants of 4.5-day-old chick embryonic neuroretinas with mesenchyme were exposed to Methotrexate (MTX) in medium 199 with embryo extract. Proliferative responses of the cultured neuroretinas were followed radioautographically by administration of 3H-thymidine to the cultures. The DNA synthetic, mitotic and pyknotic responses of the ventricular cells of the neuroretina were followed over a 16-hour period. The responses observed suggested that MTX caused a synchronization of the ventricular cells in the pre-mitotic phases with no direct inhibition of mitosis. Furthermore, prolonged exposure to MTX resulted in the accumulation of labeled pyknotic cells, indicating a decline in the regenerative capacity of the proliferative ventricular cells.
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  • 53
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    Journal of Morphology 150 (1976), S. 369-397 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Successive tracheal cuticles of the dorsal longitudinal trunks are studied with the electron microscope. Minor differences seen at the light microscope level are seen as major qualitative and quantitative ones at the ultrastructural level. The larval and pupal cuticles are secreted by similar epithelial cells; these possess large polytene chromosomes. Cell division and possibly cell replacement occur prior to adult cuticle secretion. The findings are discussed in terms of cell specificity, intra- and inter-cellular pattern formation. This simple epithelium, the individual cells of which are capable of producing different cuticles, is interesting since the system is also shown to be responsive to hormone application.
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  • 54
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    Journal of Morphology 150 (1976), S. 453-461 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Eggs of the common snapping turtle, Chelydra serpentina, were incubated at constant temperatures ranging from 20°C to 30°C, At hatching, the oviducts were absent or incomplete in males; the testes were differentiated. In females at hatching, the oviduct was intact hut in some cases the gonad retained bisexual characteristics. Three months after hatching, the ovary was differentiated and contained follicles. Eggs incubated at 20°C and at 30°C developed into females in 100% of the cases. At 26°C, 99% of the individuals were males; at 24°C, 100% were males. More males than females developed at incubation temperatures of 22°C and 28°C.
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  • 55
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: New blastozooids of Polyzoa vesiculiphora, the polysytelid ascidian are produced by pallial budding of three types depending on the method of “isolated bud” formation; stolonic, planktonic and intermediate types. Differences among each type of bud are attributed to behavior of test-vessels composing a part of the bud. Isolated buds produced by each type are essentially equal in terms of their internal structures and their subsequent fate, and develop independently of their parent zooids. New test-vessels originate directly from the epidermis of a “prefunctional zooid,” while the test-vessels derived from the parent zooid finally disintegrate. The new test-vessels extended with branching under the ventral side of a “functional zooid,” ascend to the lateral side of it and participate in bud formation. Budding regions exist in three dimensions on the lateral wall of the mantle of the functional zooid, especially the right posterior part. During the life cycle of one functional zooid, the stolonic type buds appear at early and/or aged stages. Appearances of the stolonic type buds in early stages tend to repress those of the planktonic types. The number of planktonic type buds formed on a functional zooid at the same time is many more than that of the stolonic type. Such budding features are discussed from the viewpoint of behavior of the test-vessel system.
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  • 56
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    Journal of Morphology 150 (1976) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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  • 57
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    Journal of Morphology 148 (1976), S. 137-159 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The gross and microscopic anatomy of the venom producing parotoid glands of Bufo alvarius has been studied by light and electron microscopy. Histochemical reactions for the presence of venom constituents and of components in biochemical pathways in the synthesis and release of venom were performed. The gland is composed of numerous lobules. Each lobule is an individual unit with a lumen surrounded by a double cell layer. Microvilli of the outer layer interdigitate with microvilli of the inner layer. Cells of the outer layer resemble smooth muscle cells, are rich in adenosine triphosphatase and glucose6-phosphatase, and contain numerous pinocytotic vesicles, glycogen granules and various organelles, These organelles include “crystalloids” of what seem to be highly organized agranular reticulum. These outer layer cells probably function in some aspects of venom synthesis, active cellular transport and contraction in the discharge of the secretory product. The inner cell layer demonstrates a positive chromaffin reaction, contains steroid material, various organelles, some pinocytotic vesicles and glycogen granules, and appears devoid of a plasmalemma on its inner surface. This layer is probably involved in venom formation and release via an apocrine type of secretion.Bufo alvarius parotoid gland shows significant morphological and histochemical differences from that of B. marinus and more nearly resembles a typical steroid producing organ.
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  • 58
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    Journal of Morphology 148 (1976), S. 177-184 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Small local wounds on the surface of the mouse lung, produced by cauterization, healed by a typical reparative process involving c1 migration and increased cell division in alveolar and bronchial tissues. The local cell division response closely resembled the compensatory cell division response in the same organ which follows unilateral pnemnonectomy or unilateral collapse of the lung: initially there was an increase in the rate of DNA synthesis followed by an increased rate of entry into mitosis, both of these functions returning to normal levels within a few days. It is therefore suggested that both types of response are governed by a single regulatory mechanism. The results do not support the view that the rate of cell division is regulated by systemically-circulating mitotic control factors and it is proposed that changes in the cell division rate, both in the reparative and in the compensatory types of response, are determined by local alterations ill the concentration of regulatory metabolites.The magnitude of the cell division response was much greater in bronchial than in alveolar tissue. a result which is consistent with the view that new alveolar tissue may be produced by the proliferation and differentiation of bronchial cells.
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  • 59
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    Journal of Morphology 148 (1976), S. 161-176 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Larvae of the stolidobranch ascidian Metandrocarpa taylori molt a thin sheath upon settling, then metamorphose and radiate a larval complement of vascular ampullae upon the substrate. These ampullae thereafter regress, “rest” in a reduced condition for several weeks, and then regrow into the oozooids definitive array of vascular ampullae in accompaniment to the development of the oozooidal vascular nest of test-vessels. Pallial buds emerge some four months after the larva settles; the oozooid has by then grown to a length of at least 2 mm and its vascular nest is surrounded by at least 16 vascular ampullae. Oozooids bud one to five buds (mean, 2.6) in a rather short period of blastogenic vigor, then persist in the colony. Late buds are frequently aborted. Buds appear anywhere around the basal margin of the oozooid, but more often on the left than the right and more often posteriorly than anteriorly. As other studies have observed with blastozooids, this study notes an integration of budding and the disposition of the elements of the test-vessel system of oozooids. Buds emerge oriented tangentially to the parental basal margin at the bud-site, then often rotate to point their anterior ends away from the parent. No larvae metamorphosed into oozooids with situs inuersus uiscerurn, but in this study two oozooids extruded blastozooids showing this anomaly; these blastozooids budded reversed zooids in turn, so that entire clonal lines showed the anomaly.
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  • 60
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Guinea pig soleus, medial gastrocnemius and vastus lateralis muscles were compared for spindle density and distribution, number of intrafusal fibers per spindle and histochemical appearance of the axial bundle. A total of 326 spindles was used in the comparisons. Spindle density was over four times greater in the soleus than in either the medial gastrocnemius or vastus lateralis. In the soleus the spindles were distributed at random, but in the other two muscles no spindles were found in those fascicles in which fast-twitch glycolytic extrafusal fibers predominated. The average number of intrafusal fibers per spindle varied by less than 5% between the three kinds of muscles. About 80% of all spindles located had four intrafusal fibers, two of the nuclear bag type and two of the nuclear chain type. The histochemical appearance of the axial bundle was the same in each kind of muscle. Based on intensities of the myofibrillar adenosine triphosphatase reaction product at polar regions nuclear bag fibers were separable into two histochemical groups; nuclear chain fibers were of only one histochemical type.
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  • 61
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    Journal of Morphology 148 (1976), S. 193-207 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To establish a morphological baseline for experimental studies of differentiation using the cement gland as a model, the following observations are added to those on record. The elongated cells of Xenopus laevis cement glands have an internal organization displaying five distinct zones differing in structure and specialized function. The apical zone contains packed secretion vesicles apparently belonging to two different types. The transit zone appears to be devoid of major biosynthetic activity and contains secretion vesicles migrating toward the surface. The zone of biosynthesis is typically organized in concentric regions. The very elongated nucleus lies in the next zone. Finally, the storage zone is characterized by lipid droplets and yolk platelets.Only quantitative differences are observed between cells of young and mature cement glands. Though all cells have the same general organization they may probably be divided into two subtypes according to the structure of their cytoplasm. The epithelial cells surrounding the gland differ according to their position along lateral or basal borders.
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  • 62
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    Journal of Morphology 148 (1976), S. 209-225 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of the mature sperm of the holothurian, Cucumaria miniata, and the ophiuroid, Ophiopholis aculeata, is described with particular reference to their acrosomal and centriolar satellite complexes, and compared to the sperm of other echinoderms.In Cucumaria, the acrosome is in the form of a diffuse acrosomal vesicle. It is unusual in that it apparently lacks an acrosomal membrane. A membrane separating the acrosomal vesicle from the periacrosomal material may not be equivalent to a typical inner acrosomal membrane. In Ophiopholis, the acrosome is dense, with some internal substructure, and is enclosed by a complete acrosomal membrane. In both species, the acrosome is partially surrounded by an amorphous periacrosomal mass. There is a notable absence of a subacrosomal depression and associated structures as found in other echinoderm sperm.The centriolar satellite complex (CSC) is essentially identical in both species. A reconstruction of the CSC is presented. The CSC consists of nine satellites radiating angularly from the distal centriole, each bifurcating at a dense node before inserting on a marginal ring containing circumferential microtubules. The ring is probably a cytoskeletal element. Immediately below the satellites are nine Y-shaped connectives. connecting each of the axonemal alpha doublets to the flagellar membrane.
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  • 63
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of the dorsal bristle complex and pellicle of non-developing Euplotes eurystomus is described in detail by scanning and transmission electron microscopy. The bristle-pit unit is a highly differentiated complex of organelles. The bristle complex is composed of a pair of kinetosomes (basal bodies) joined by a connective. The anterior kinetosome bears the bristle cilium, which contains a polarized network of particles (“lasiosomes”). The posterior kinetosome bears a very short, knob-like “condylocilium,” and has an associated striated fiber. Accessory ribbons of microtubules are also associated with the kinetosome couplets. Parasomal sacs, a septum connecting the bristle cilium to the anterior wall of the pit, core granules of the kinetosomes, and large membranous ampules are described. The organization of the bristle complex bears many similarities to the somatic ciliature of other ciliates. The pellicle of Euplotes is composed of a continucus outer cell membrane subtended by membranous alveoli, which contain a “fibrous mat.” Two sheets of subpellicular microtubules (longitudinal and transverse) are located just beneath the alveoli. The “epiplasm” seen in some other ciliates is apparently absent in Euplotes. The texture of the cell surface is a pattern of folds or rugae composed of the outer cell membrane and the upper membrane of the alveolus. The pattern of rugae probably defines the “silverline-system” of light microscopy.
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  • 64
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Hypotrichs are among the most complex ciliates in terms of morphology and development. To study the fine structure of cortical morphogenesis associated with cell division in Euplotes eurystomus, three different methods of observation were employed: light microscopy of protargol-stained specimens, scanning electron microscopy of cells prepared by critical point drying, and transmission electron microscopy of sectioned material. Observations on the stages of morphogenesis give much new information about cortical development, particularly about proliferation and aggregation of kinetosomes (basal bodies), ciliary outgrowth, the topography of morphogenesis, cirrus resorption, and growth of the pellicle. During the formation of new cirrus the process of kinetosome proliferation is atypical, i.e., groups of prokinetosomes are seen oriented at random and, in some cases, prokinetosomes apparently are formed at a distance from nearby young kinetosomes. That the new cirri develop in surface grooves, the grooves elongate into “tracks,” and (in some cases) grooves are partitioned into separate tracks suggests that the grooves play a role in the orderly migration of the new cirri on the cell surface. Conspicuous morphogcnctic changes in the cell surface involve local growth of the pellicle. The process of pellicle growth apparently involves two basic steps: (a) growth of the outer cell membrane to form “bare regions,” and (b) formation of alveoli in the bare regions. Alveolar sheets are formed by fusion of alveolus precursor particles. Cirrus resorption is sequential over several stages of development, and old cirri are resorbed as the new cirri impinge on them. As the old cirri regress, both in situ resorption and retraction of axonemes into the cytoplasm occur.
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  • 65
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    Journal of Morphology 149 (1976), S. 33-51 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mature annelid cuticle contains orthogonally oriented collagen in a matrix capped superficially by a dense epicuticle with external corpuscles. The underlying epidermis is a simple columnar epithelium with two major cell types, mucous-secreting cells which secrete through channels in the cuticle to the exterior of the worm, and “supportive” cells which presumably produce and increase the cuticle by secreting into it.The structures of supportive cells, previously interpreted as specialized for establishing interfibrillar collagen order, are revealed by glutaraldehyde fixation as common cellular components without the qualities deemed useful to align collagen. Cell processes which penetrate and sometimes pass completely through the cuticle are not stable, not in geometric order, and lack cilia-like structure. Cilia, unlike the ubiquitous cellular processes, are highly restricted to regions of the epidermis with specialized functions. Cellular control, or other control, of collagen fibrillogenesis remains unestablished.
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  • 66
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    Journal of Morphology 149 (1976), S. 121-137 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Early embryogenesis is described for the southern corn rootworm, Diabrotica undecimpunctata Howardi Barber, at 24 ± 1°C. During the first four hours following oviposition, the maturation divisions and syngamy are completed. Morphological changes in the second polar body accompany syngamy. Cleavage divisions and energid migration occur during the fourth to the tenth hour. The vitellophags, which appear during cleavage divisions, are distinguished from the blastema-bound nuclei by having smaller, more densely staining nuclei. After completion of a uniform blastoderm (11-14 hour), cell division ceases until the completion of the germ band and the formation of the embryonic membranes (22 hour). This species has a pattern of amnion formation that is different from most Coleoptera but is shared with a few other chrysomelids, some Isoptera, and some Odonata.
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  • 67
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    Journal of Morphology 149 (1976), S. 105-119 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Each ocellar nerve in the house cricket Acheta domesticus contains giant nerve fibers of 10-15 μ diameter, characterized in Golgi Cox preparations by a single row of short collaterals which runs along nearly the entire length of a fiber. Numerous long collaterals are given off by thin fibers in the ocellar nerve; medium-size fibers give off relatively few collaterals.The lateral ocellar tracts extend posteriorly through the dorsal protocerebrum, crossing the protocerebral bridge dorsally. The smaller median ocellar tract runs more ventrally through the pars intercerebralis; posterior to the bridge its fibers turn out toward the lateral nerves. Golgi and cobalt preparations reveal branching of giant and mediu_-size ocellar fibers posterior to the bridge at two levels, forming bilateral regions of ocellar neuropile. No ocellar processes appear to be given off to the corpora pedunculata, centra! body, nervi corporis cardiaci, antenna! lobes, or circumesophageal connectives; it is uncertain whether ocellar collaterals extend into the protocerebral bridge or optic lobes. Cell bodies of giant and medium-sized fibers are located in the pars intercerebralis.
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  • 68
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    Journal of Morphology 149 (1976), S. 73-103 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The general morphology of the gills is similar in larval (ammocoetes) and parasitic adult sea lampreys, Petromyzon marinus, despite different methods of ventilation necessitated by their feeding habits.The gill lamellae are supported by randomly-distributed pillar cells which enclose blood spaces and collagen columns. The distribution of these cells in lampreys is different from that of higher fishes and it may be inefficient for respiratory exchange. The presence of cytoplasmic microfilaments suggests that these cells have the ability to reduce the lamellar blood spaces through contraction. Marginal channels at the tips of the lamellae are lined only by endothelial cells.The thickness of the water-blood pathway in lampreys falls within the range described for higher fishes, with the most efficient gas exchange likely occurring at the lamellar tips where only a single layer of epithelial cells is present. The abrupt increase in height of the epithelium near the lamellar bases in adults, compared to the gradual transition in height along the lamellae in ammocoetes, is perhaps reflective of higher oxygen requirements during the parasitic stage. The consistent appearance of wide, lateral intercellular spaces within the respiratory epithelium of lampreys indicates possible involvement of these spaces in transport.Mucous secretion appears to be an important function of the superficial platelet cells in ammocoetes. “Mitochondria-rich” and “mitochondria-poor” superficial cells are observed in both ammocoetes and adults, with the mitochondria-rich cells more prevalent toward the lamellar bases. The possibility that at least some of these cells may be involved in absorption is discussed. Mitochondria-rich cells in the interlamellar region are morphologically different in ammocoetes and adults but all possess an abundance of smooth endoplasmic reticulum and hence resemble “chloride cells” of higher fishes. The similarity of these cells in the parasitic adult lamprey to chloride cells of marine fishes may reflect the potential of the adult lamprey to osmoregulate in salt water. A scarcity of these cells in ammocoetes and their resemblance to chloride cells in freshwater fishes may reflect the restriction of larval lampreys to a freshwater habitat.
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  • 69
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sexual dimorphism in the distribution of antennal sense organs is common among adults of the genus Periplaneta. In three out of the four strains of Periplaneta americana examined, adult males had more contact chemoreceptors than females. In the fourth strain of P. americana and in P. australasiae, P. brunnea, P. fuliginosa, and P. japonica, no statistically supportable sexual dimorphism of contact chemoreceptors was found. However, in all strains and species of Periplaneta examined, sexual dimorphism was found in the total number and/or density of olfactory sensilla. Male adults had nearly twice as many olfactory sensilla as female adults. These observations are consistent with the behavioral observation that males within the genus Periplaneta rely on the reception of an airborne pheromone for the initiation of courtship behavior. In P. americana, where sexual dimorphism was found in the contact chemoreceptors, contact stimuli release the full wing raising display and presentation in males during courtship.
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  • 70
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    Journal of Morphology 149 (1976), S. 183-197 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The main excretory ducts (MED's) from the submandibular gland of adult cats were examined by electron microscopy. The ducts consisted of a pseudostratified epithelial lining surrounded by abundant connective tissue and numerous, small, longitudinally-oriented blood vessels. The taller epithelial cells were closely coherent, without the luminal clefts between adjacent cells that are characteristic of rat MED's. In the cat, these cells lacked basal membrane specialization, but showed considerable lateral interdigitation. Some microvilli were present on the apical surface. In a'few rare cells, the luminal surface bore cilia of typical appearance. The smaller, pyramidal basal cells had irregular basal surfaces that gave rise to one or more long cytoplasmic processes. The basal surface of the pyramidal cells was studded with hemidesmosomes. The cytoplasm contained abundant tonofilaments, which sometimes aggregated in prominent perinuclear bundles. Occasional goblet cells were present in the duct wall.MED's perfused either in situ or in a perfusion chamber with Locke's solution also were studied. Even after perfusion of 160 minutes duration, the ultrastructure of the ductal epithelium showed remarkably few alterations. The MED model system thus remains stable long enough to carry out physiological experiments which may produce ultrastructural alterations.
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  • 71
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    Journal of Morphology 149 (1976), S. 199-221 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The byssus attachment plaque and the tissues responsible for its formation were studied in M. califomianus by light microscopy and by transmission and scanning electron microscopy. It was shown that the plaque consists of at least three phases which ultrastructurally resemble three secretions considered to be collagen, mucoid material and polyphenol. The mucoid and polyphenol appear to mix as a colloidal suspension in which the latter is the continuous phase and forms the definitive bonding surface. Plaque collagen represents an extension of thread material into the cementing substance.Stimulated secretion within the ducts and distal depression of the mussel's foot shows a continuum of increasing heterogeneity from the inner toward the outer regions. This reflects the distribution of exocrine cell apices wherein exocytosis of polyphenol granules predominate deeply, mucous granules superficially and collagen granules in between.It is proposed that the morphology of the plaque conforms to theoretical physical-chemical requirements for adhesion under water.
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  • 72
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    Journal of Morphology 149 (1976), S. 159-182 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this paper the cranial arteries, cranial arterial foramina, and bony canals of the Cheloniidae, Chelydridae, Pelomedusidae, and Chelidae are described in detail. From skull studies and published material, the general cranial arterial patterns of all the turtle families can be inferred. Sea turtles, the Cheloniidae and Dermochelyidae, possess both a large stapedial artery and a large artery supplying the orbit, which is possibly similar to the primitive cranial arterial pattern for turtles. From a primitive pattern in which stapedial and palatine arteries supply the orbit, the Chelydridae and Testudinidae retained a large stapedial artery and reduced the palatine artery, while the Kinosternidae and Dermatemydidae developed a large palatine artery and reduced the stapedial artery. The Trionychidae and probably the Carettochelyidae evolved a complex arterial pattern in which the stapedial artery was reduced somewhat and the pseudopalatine artery was substituted for the palatine artery. Pleurodires in general retained a large stapedial artery and reduced or eliminated the palatine artery. The Podocneminae, including the Madagascar species, developed a highly modified carotid canal, which is found in no other turtle group. The facts which have been presented should aid in fossil skull studies and in understanding the evolutionary background of recent turtles.
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  • 73
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    Journal of Morphology 149 (1976) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 74
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ethidium bromide (l0 μg/ml) and bromodeoxyuridine (25 μg/ml) were used to sensitize selective cell organelles to visible wavelengths of an argon ion Her (488 and 514 nanometers). Ethidium bromide was shown to be salabtlve In sensitizing nucleoli, chromosomes, and the centriolar region of PTK2 cells to the laser microbeam. Similarly, BrDU sensitized chromosomes to the microbeam irradiation. The lesions produced on the chromosomes when either agent was used appeared as a phase paling of the irradiated segment. Nucleolar lesions also appeared as a phase paling, and the centriolar region alteration appeared either as a phase paling or a phase darkening.
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  • 75
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    Journal of Morphology 150 (1976) 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
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  • 76
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    Journal of Morphology 149 (1976), S. 547-565 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The labial gland of the adult sphingid moth, Manduca sexta, is composed of five distinct regions, each made of a single cellular type. Four of these regions are derivatives of the single specialized cellular population that makes up the caterpillar labial duct.Both the larval labial duct and its derivatives are large, polyploid cells with pleiomorphic nuclei. There is a definite cellular continuity between the larval and adult forms of these cells throughout metamorphosis; no mitoses or cell deaths are seen to occur in the gland during transformation.Cytological studies indicate that in the process of cell transformation the ducts first “dedifferentiate,” elongate, then redifferentiate. Intermediates in this process have well defined structures which should make this system useful in studying covert events in the transformation process.
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  • 77
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    Source: Wiley InterScience Backfile Collection 1832-2000
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    Notes: Larval Typhlotriton spelaeus collected from five caves in Pulaski Co., Missouri, were kept as larvae or induced to transform in darkness or continuous fluorescent illumination. Larvae maintained in darkness for 215 and 279 days had smaller eyes, smaller rod inner and outer segments, and fewer metaphase figures in the genninative zone of the neural retina than comparable larvae maintained in light (258 lux). Except for visual cell size, differences were small and for each characteristic exceptions were observed. One larva kept in light showed early retinal degeneration comparable to that in transformed adults of T. spelaeus. All larvae exhibited optomotor behavior both before and after the experiment.Among animals induced to transform by L-thyroxin and maintained in darkness 111 to 366 days, visual cell and pigment epithelium degeneration was more extensive and more frequent than in animals kept for the same length of time in light (237-298 lux). In darkness the frequency of animals with retinal degeneration increased between 111 and 366 days. In light some animals exhibited pigment epithelium reduction with normal visual cells, and others had free, pigmented cells in the subretinal space. These effects were not comparable to degeneration in darkness. Eyelids covered the eyes of only a few animals in both light and dark treatments. The extent of eyelid encroachment over the eye was greater in darkness than in light. Most animals exhibited optomotor responses after experiments, but responses of animals kept in darkness were impaired in comparison to those of animals kept in light.
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  • 78
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    Journal of Morphology 150 (1976), S. 79-115 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The pectoral myology and osteology of the cyprinoids Notemigonus crysoleucas, the golden shiner, and Catostomus commersonnii, the common white sucker, resemble those of generalized, lower teleosts in structure and function, except in features related to the manipulation of the massive fifth ceratobranchial of cyprinoids by muscles attaching on the girdle. Catostomus is more specialized in having unique intercostal muscles to the girdle, complex subclavian arteries and lack of a superficial trapezius muscle. The bony pectoral anatomy of the siluriform, Ictalurus nebulosus, the brown bullhead, is highly specialized in relation to the presence and locking of the massive pectoral spine which is formed of fused dorsal and ventral propterygial rays; there is consolidation of the girdle through fusion of bones, presence of unique stabilizing bony structures, firm symphyseal union of bilateral girdles and the presence of friction-surfaces of girdle and spine for locking. The movements of the spine are specialized in the greater guidance offered by the girdle. Myological specializations are related mainly to ventral appendicular muscles which lock the spine. The nervous and arterial systems are generalized.
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  • 79
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    Notes: The inferior lobes of the shark hypothalamus were examined with light, transmission and scanning electron microscopy. The cells bordering the floor of the lateral recess appear to be typical liquor-contacting neurons. With scanning electron microscopy (SEM) the apical ends of these cells are seen to bulge into the ventricular lumen. In contrast, the roof is lined by a more typical ependymal cell characterized by numerous cilia and microvilli. In addition, SEM reveals several kinds of supraependymal cells with processes that appear to penetrate the ventricular lining. A periventricular nucleus underlies the ependymal cells. Neurons of the periventricular nucleus contain numerous lipofuchsin granules. The rest of the inferior lobe consists of many neuronal fibers. The morphology of the hypothalamic inferior lobe is discussed in relation to its possible role in feeding and aggressive behavior in both elasmobranchs and teleosts.
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  • 80
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    Journal of Morphology 150 (1976), S. 711-725 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fine structure of midgut cells in two species of Cladocera (Crustacea: Branchiopoda) has unique features when it is compared to that in the midguts of other arthropods. Features which suggest that food is absorbed in digested form are: the presence of the peritrophic membrane, the glycocalyx, the almost complete absence of pinocytotic vesicles, and the large surface area of a great number of microvilli. Digested products presumably pass into the hemolymph through the network of extracellular canals and cisterns surrounding the basal ends of intestinal epithelial cells. Cells of the midgut in Cladocera differ from those of other arthropods in the simplicity of their basal plasma membranes, which are not highly folded. The small number of membrane invaginations suggests that water reabsorption is very slight, as is the usual condition in aquatic animals.The origin and evolution of peculiar structures we call “multivesicular-like bodies” have been investigated. These display a variety of different morphological features. Some contain acid phosphatase activity and are considered as specialized lysosomes.
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  • 81
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    Journal of Morphology 150 (1976), S. 805-823 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The arrangement of collagen fibers over the body surface in the basement lamella of Pseudaeris and Xenopus tadpoles is described. It can be viewed by scanning microscopy after removal of epidermis and basal lamina by trypsin treatment of alcohol fixed tissue. The orthogonal array is modified in regions where fiber direction changes extensively such as the base of the ventral fin or the posterior part of the head. In these regions “exceptional points” in the orthogonal pattern occur, as described by Rosin (1946). The pattern is bilaterally symmetrical. In the region of the nasal opening the orthogonal pattern is replaced by a mat of randomly oriented fibers. In tail regeneration the wound area is marked by aberrant disposition of collagen anteriorly then a mat of randomly disposed fibers followed posteriorly with a sharp transition to the orthogonal pattern of the regenerate. No fiber terminations could be seen in normal or regenerating regions of the lamella.
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  • 82
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    Notes: Sperm induction pores, tubuli annulati, rami sacculi, sacculus foemineus, cornu sacculus and acantho-membranous hood in female Dermanyssus gallinae support the probability of coxal insemination as reported for some other mesostigmatid species.Development of the circular testis in males (from fusion of two anterolaterally projecting protonymphal testicular arms) and formation of haploid (n = 3) spermatids from haploid (n = 3) spermatogonial cells is entirely mitotic. Spermatogenesis begins within one hour after protonymphal feeding and continues through adult ecdysis in normally fed individuals. Nutritional deficit causes cessation of spermatogenic divisions in deutonymphs starved 23 days, but is rapidly rejuvenated upon feeding. No rejuvenation of division was observed in adult males given the opportunity to feed, thus adult males might not feed.
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  • 83
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    Journal of Morphology 148 (1976), S. 227-253 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The functional anatomy of the hindlimb of 12 species of viverrids was studied with relation to locomotion. The animals were allocated to primary locomotor categories on the basis of their anatomy and locomotion.The climbing, arboreal walking category (Nandinia binotata) is characterized by a small sacroiliac articulation, the iliopsoas inserts onto a medially located lesser trochanter and the femoral condyles are not posteriorly placed. The hindfoot is plantigrade and its structure permits considerable movement. The pads are soft and the claws retractile.Representatives of the arboreal and terrestrial walking and jumping category (Genetta genetta, G. servalina, G. tigrina) have a plantigrade forefoot and digitigrade hindfoot. The lesser trochanter is more posteriorly placed than in the climbing category. A previously undescribed muscle, the caudofemoralis profundus extends from several anterior caudal vertebrae to the femur. The tibio-astragular joint restricts supination of the foot. There is little mediolateral movement in the digitigrade foot. The claws are retractile.In the general terrestrial walking and scrambling group (Helogale parvula, Mungos mungo, Atilax paludinosus, Bdeogale crassicauda, Herpestes ichneumon, H. sanguineus) the animals have essentially similar hindlimbs except for size differences and modifications to the feet. Helogale and Mungos have large medial epicondyles on the humerus and large terminal phalanges. Bdeogale has a vestigial first metatarsal, while Atilax can splay its digits. In all species the distal phalanges are non retractile.The trotting category (Civettictis civetta. Ichneumia albicauda) is characterized by longer epipodials and metapodials and a more proximal position of muscle bellies. Most of the adaptations minimize rotation, adduction and abduction of the leg and supination of the foot. The metatarsals are closely adjoined and the distal phalanx is stout and non -retractile.There appear to be two levels of locomotory adaptation. Major adaptations affect the whole appendicular skeleton and are used to assign animals to primary locomotor categories. Minor adaptations occur mainly in the foot and indicate the more specific habits of the animal.
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  • 84
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  • 85
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    Journal of Morphology 148 (1976), S. 255-264 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The modified midventral scales on Percina males probably function to induce tactile stimulation of the female during spawning. The midbelly row of modified scales presumably evolved as a result of increased selective advantage of larger and more strongly toothed scales on the midventer; primitive and intermediate conditions in the evolution of the modified scales as well as a distinctly modified row are extant, The morphology of the scales varies seasonally and ontogenetically. The scales are permanent rather than deciduous as described in the literature interspecific variation of the modified scales is pronounced intersubgenerically. less so intrasubgenerically.
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  • 86
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    Journal of Morphology 148 (1976), S. 265-286 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Plethodontid salamanders capture prey by projecting the tongue from the mouth. An analysis of theoretical mechanics of the hyobranchial skeleton is used to formulate a working hypothesis of tongue movements. Predictions that the skeletal elements of the tongue are included in the projectile and that the hyobranchial skeleton is folded during projection are central to the analysis, When decapitated in a particular way, salamanders project the tongue, and it is not retracted. When these heads are fixed and sectioned, examination confirms the predictions, In turn, these observations are used to refine the working hypothesis and to generate a general model of tongue dynamics for plethodontids. Muscles performing the major roles of projection (subarcualis rectus I) and retraction (rectus cervicis profundus) are identified. The skeleton is folded passively along a morphological track having the form of a tractrix, Predictions concerning the shape of the track and the exact configuration of the folded skeleton are confirmed by study of sectioned material. The skeleton unfolds along the track during retraction and is spread into the resting state, The model developed herein will be used as a basis for predictions concerning selection patterns in the family and for analytical purposes in comparative and evolutionary studies.
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  • 87
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    Journal of Morphology 148 (1976), S. 329-336 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Scales on the hairs of pollinating bats spread out at an angle to the main hair shaft. In contrast, the hairs of most bats not associated with plants are relatively smooth. Both megachiropteran and microchiropteran flower-feeding bats show this divaricate scale structure which may aid in the collection of a heavy coating of pollen. Some of the pollen is transferred to subsequent flowers, but most is groomed from the fur and ingested as the only reliable nitrogen source for the bat.The tongues of nectar-feeding bats also show structural modifications which allow efficient uptake of the carbohydrate fraction of the diet.Structural specializations of the hairs and tongue are analogous to those seen in other nectar-feeding animals.
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  • 88
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    Journal of Morphology 148 (1976), S. 287-303 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The extrinsic ovarian blood vessels were studied in 134 ewes. In view of recent evidence that uterine luteolysis may involve local veno-arterial transfer of prostaglandin F2α in the ovarian pedicle, particular attention was paid to the interrelationships between veins and arteries.The ovarian artery and utero-ovarian vein are large vessels of conventional structure and lie in close apposition. Their walls are slightly thinner on their apposing sides. The ovarian branches of the ovarian artery are very tortuous, and closely intertwined with the plexiform ovarian branches of the utero-ovarian vein.An extensive plexus of small veins surrounds the ovarian artery and its ovarian branches. Within this plexus are many thin-walled, dilated regions, interspersed with narrow, thick-walled segments. Valves are inconstantly present at sites of entry of branches of the plexus into the major veins. Small numbers of arterio-venous anastomoses are present in the distal part of the ovarian pedicle.Unless blood can flow in a veno-arterial direction through arterio-venous anastomoses or capillary beds, the structural barrier between uterine venous and ovarian arterial blood is substantial.
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  • 89
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    Journal of Morphology 148 (1976), S. 305-327 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Examination of the vertebral columns of representatives of all families of salamanders revealed that, in contrast to the condition found in most other vertebrates, salamander spinal nerves often pass through foramina in the vertebrae. Two kinds of spinal nerve foramina were found: those in the anterior halves of vertebrae, and those in the posterior halves. In addition, many salamanders retain intervertebral nerves. However, within each family or, in a few cases, subfamily there is a characteristic pattern of spinal nerve-vertebral relationships.The first spinal nerve of all salamanders exits through a foramen in the anterior half of the atlas. All more posterior nerves are intervertebral in the families Cryptobranchidae, Hynobiidae and Proteidae. The posterior caudal nerves exit through the posterior halves of the caudal vertebrae in the family Amphiumidae, while in the subfamilies Dicamptodontinae and Rhyacotritoninae all post-sacral nerves exit through the posterior halves of the vertebrae. All but the first three nerves exit through posterior foramina in the family Plethodontidae and the subfamily Ambystomatinae, while all but the first two nerves pass through posterior foramina in the families Salamandridae and Sirenidae.Several fossil salamanders were also examined. These showed that the amphiumid and dicamptodontine-rhyacotritonine nerve patterns had evolved by the Late Cretaceous, and the sirenid pattern had probably evolved by that time. Other Cretaceous genera associated with the Ambystomatoidea still possessed the primitive intervertebral pattern.Using spinal nerve patterns and several other previously described morphological characters, a new hypothesis of the phylogeny of recent and fossil salamanders is presented and compared to earlier proposed phylogenies of the group. A new classification of salamander families is presented.
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  • 90
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
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  • 91
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    Journal of Morphology 148 (1976), S. 363-390 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The anatomy and function of the feeding apparatus in Iguana iguana and Uromastix aegyptius were studied by dissection, cinematic and cineradiographic techniques.The feeding behavior of these species differs from that of insectivorous lizards in the cropping action which separates a piece from the whole plant. The food is manipulated by a fleshy tongue and by movements of the whole head. There is no mastication of food. The cropping action involves movement of both the upper jaw around the atlantooccipital joint and the lower jaw around the mandibular joint; and in Uromastix only, streptostylic movement of the quadrate. Often movements of the whole head playa supplementary role in the cropping action.In both species the feeding apparatus has been modified to facilitate cropping. In Iguana the pleurodont dentition is multicusped and laterally compressed. Each tooth forms a shearing blade whose function does not require contact with other teeth. In Uromastix the dentition is acrodont and the cheek teeth are massive and lack cusps. Occlusion is necessary for shearing plant material. The skull system of Uromastix also has a number of modified structures which allow protraction and retraction of the lower jaw to facilitate cropping while maintaining a gape equivalent to that in Iguana. It is suggested that the differences in the feeding apparatus between Iguana and Uromastix are attributable to differences in the mode of tooth replacement and implantation.
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  • 92
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    Journal of Morphology 148 (1976), S. 337-361 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gametogenesis of a compound ascidian Botryllus primigenus was studied histologically. On either side of the zooid (stage 9), in the gonadal space between the epidermis and the atrial epithelium, either a single testis or a complex of an egg follicle and a testis can be formed. The egg follicle consists of a single ovum (occasionally two ova) and its accessory cells and is connected with the atrial epithelium by the follicle stalk. The egg follicle is always accompanied by the brood pouch, a diverticulum of the atrial cavity. The testis is equipped with a vestigial spermiduct and is attached to the atrial epithelium.Buds of stage 8 comprise, besides the developing testes and, egg follicles, loose aggregations of hemoblasts and oocytes of early developmental stages, which are already accompanied by primary follicular cells. Both the oocytes and the primary follicular cells seem to arise from the hemoblasts. The young oocytes are isolated in the gonadal space of the buds nnd are transferred to buds of the succeeding generations until they finally mature.In the bud of stage 3, a compact mass of cells appears, attaching to tbe inner vesicle on either side of the body. It is derived from the hemoblasts lodged there in the preceding generation and presumably also from the circulating hemoblasts. When the cell mass receives a large oocyte derived from the preceding generation, part of the cell mass differentiates into egg envelopes, forming an egg follicle, and a follicle stalk and the remainder into a testis. When the cell mass receives no oocyte, it differentiate as a whole into a testis. In the egg follicle thus formed the outer and inner follicular cells increase in number by mitotic division. Subsequently, initial test cells are derived from the inner follicle by migration across the developing chorion; then they increas2 in number by mitosis. In the testis, meiosis and spermiogenesis take place.
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  • 93
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    Journal of Morphology 148 (1976), S. 427-451 
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    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fertilized egg of Hemioniscus balani, a viviparous isopod, is encased in two envelopes, I and II, the structure of which is described.In the course of its development, the embryo secretes five successive sacs called embryonic envelopes. Both their structure and the means of secretion by the embryo are analyzed through thin sections. The presence of these successive secretion cycles together with exuviations involving these embryonic envelopes lead us to believe that during embryonic development in Hemioniscus balani, embryonic molting cycles exist.The appearance and shedding of the envelopes of the fertilized egg and embryo allow determination of ten embryonic stages which are briefly described.
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  • 94
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    Journal of Morphology 148 (1976), S. 391-426 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Seven to nine days after infection of the definitive host (rat) by cystacanths, the genital primordium of the female acanthocephalan is transformed from a fragmented mass of cells into discrete ovarian balls. This is accomplished by envelopment of free germinal cells by somatic tissue which originates from the ligament sac primordium. Germinal cell nuclei then undergo repeated mitoses until about 21 days of development, with concurrent formation of oogonial syncytia which occupy the interior of the ovarian balls. Oocytes, derived from these oogonia, move to the periphery of the germinal syncytia for differentiation, growth, fertilization, shell formation, and release from the ovarian ball. After oogonial proliferation ceases, continued growth of the ovarian ball apparently results from increase in size of already present cells.Free-floating mature ovarian balls are found in the dorsal ligament sac; each consists of germ cells in various developmental stages, enveloped and pervaded by a multinucleate matrix syncytium of somatic origin, which functions as a follicle. Spermatozoa pass through the matrix cell for the internal fertilization of mature oocytes. Myelinated structures of an undetermined nature were found to correspond to previously reported polar bodies. After 100 days post-infection, the somatic matrix syncytium begins to manifest the degenerative effects of aging. The germinal tissue exhibits no subcellular signs of senescence by 154 days, but decreases in amount in older worms.
    Type of Medium: Electronic Resource
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  • 95
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976) 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 96
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 148 (1976), S. 453-468 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Oildroplets in the eyes of terrestrial vertebrates are spherical cellular organelles that stain for lipids, have no discernible internal structure, and often contain carotnoids and possibly other chemicals. A survey of 97 species of anuran amphibians (frogs and toads) revealed that all speccies of 16 families surveyed possessed yellow oildroplets of varying size in the cells of the pigment epithelium, except for three species that appear to have secondarily lost them during evolution. Furtbermore, 25 species of six families also possess colorless oildroplets at the distal end of the inner segments of single cones and principal cones of the double-cone system; two species of the Ranidae appear to have secondarily lost such retinal oildroplets. Every species possesses epithelial or retinal oildroplets or both. Lastly, small oildroplet-like inclusions were discovered in the red blood cells of two species.All of Walls' ('42) summary generalizations about anuran oildroplets are incorrect: oildroplets are not restricted to the Ranidae, are not yellow when found in the cones, and do not correlate with phototactic behavior in 87 species. Evidence is reviewed suggesting that the primary function of anuran oildroplets is chemical storage, perhaps related to the visual pigment cycle. Oildroplets in the cones may additionally act as filters of ultraviolet radiation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 97
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The anatomy and ultrastructure of the lizard kidney (Sceloporus cyanogenys) have been studied by light and electron microscopy. The number of glomeruli was counted' in serial sections and estimated to be 2,000 (in the two kidneys). Beginning with the glomerulus and Bowman's capsule the nephron segments are sequentially: (a) proximal tubule; (b) intermediate ciliated segment consisting of a proximal and distal part; (c) distal tubule, which can be divided into two segments, followed by (d) connecting tubule and (e) initial collecting duct. The initial collecting ducts from several nephrons open into the collecting duct. Tubular epithelium in this lizard has similarities to that of other reptiles, The lateral borders do not overlap like in mammals, but interdigitate by fingerlike projections. The length of the nephron segments was measured in disected tubules and the diameter was measured on light and electron micrographs. From these measurements estimates of inner tubular surface area were made. Together with data from physiological studies (Stolte et al., '76; Schmidt-Nielsen, '76) the estimated surface area was used to calculate transport rates per unit area across the epithelium. Comparisons of structure and transport rates were made between S. cyanogenys and other reptiles and mammals.
    Additional Material: 1 Tab.
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  • 98
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 339-351 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ultrastructure of the muscle-shell attachment was investigated in the land pulmonate snails Helix aspersa, Anguispira altemata, in the freshwater pulmonate Laevipex sp., and in the freshwater prosobranch Pomacea paludosa. In all cases, a collagenous intercellular matrix and a specialized epithelium (tendon cells) intervene between the columellar muscle and the shell. These tendon cells are characterized by hemidesmosomes at both apical and basal ends, connected by thick bundles of microfilaments. The tendon cells do not insert into the shell directly by microvilli, as formerly thought, but by an extensive network of extracellular organic fibers.
    Additional Material: 1 Ill.
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  • 99
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 353-367 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The skeletal mechanics of Astenas forbesii are examined in order to erect a theoretical framework for the evaluation of starfish skeletal systems. Guided by engineering theory, the skeleton is dissected into its functional parts and an approximation made of the stresses sustained by each. All relevant mathematical operations are demonstrated. It is shown that the whole body acts as a unit sustaining compressive forces across its oral surface and tensile stresses across its aboral surface. Two points of maximum stress are identified: the aboral ridge of the ray close to the disk and the inferior transverse amhulacral muscle (ITAM). Structural stability is conferred upon the former by virtue of its position in the body and upon the latter by the inclusion of strong tensile fibres in parallel with the muscle.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 100
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Morphology 149 (1976), S. 369-381 
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The septum primum in the mouse originates as a thickened primordium with a straight rather than a sickle-shaped ventral border. It is covered on its ventral border by anterior cushion material which is continuous over the roof of the atrium with the principal anterior cushion mass.A process of cavitation thins the septum primum and precedes actual fenestration. This process shifts the membranous septum to the left thereby providing room for the septum secundum to overlap on the right side. The septum primum cannot contact the posterior cushion until closure of the sinus venosus gutter which is described. The closure of the interatrial foramen, later the foramen primum, is accomplished by cell growth of the anterior cushion material.The ventral thick border of the septum primum contributes to the ventral limbus and the caudal thickened boundary of the fossa ovalis with some contribution from the left venous valve. These boundaries as well as the membranous portion of the interatrial septum are derived from the same primordium, namely the septum primum.
    Additional Material: 1 Ill.
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