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  • 1
    Electronic Resource
    Electronic Resource
    The effects of recombinant insulin-like growth factor I administration on growth hormone levels and insulin requirements in adolescents with Type 1 (insulin-dependent) diabetes mellitus (1993)
    Springer
    Diabetologia 36 (1993), S. 678-681 
    Details
    ISSN: 1432-0428
    Keywords: Type 1 (insulin-dependent) diabetes mellitus ; insulin requirements ; insulin-like growth factor I ; growth hormone ; adolescence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Type 1 (insulin-dependent) diabetes mellitus in adolescence is associated with reduced levels of insulin-like growth factor I, elevated growth hormone concentrations and insulin resistance. In order to determine whether restoring insulin-like growth factor I levels to normal might lead to a reduction in growth hormone levels and insulin requirements, we undertook a double-blind placebo controlled study of a single s. c. dose of recombinant insulin-like growth factor I (40 μg/kg body weight) in nine late pubertal subjects with Type 1 diabetes. After administration of placebo or insulin-like growth factor I at 18.00 hours, a variable rate insulin infusion was used to maintain euglycaemia overnight. Plasma insulin-like growth factor I, growth hormone, free insulin, and intermediate metabolite concentrations were monitored throughout the study. Recombinant insulin-like growth factor I led to a rise in plasma concentrations which reached a peak at 5.5 h (413.1±28.2 ng/ml, mean±SEM). Mean growth hormone levels between 20.00 and 08.00 hours were significantly reduced after recombinant insulin-like growth factor I (19.4±4.0 compared with 33.6±5.8 mU/l; p=0.01), as were the insulin requirements for euglycaemia (0.25±0.02 compared with 0.31±0.04 mU · kg−1 · min−1; p=0.03). Plasma free insulin levels were lower after recombinant insulin-like growth factor I administration (31.9±2.7 compared with 67.9±16.0 mU/l; p=0.001) but no significant differences in ketone or lactate levels were detected. Recombinant insulin-like growth factor I in a s. c. dose of 40 μg/kg body weight leads to a significant reduction in overnight growth hormone levels and insulin requirements in adolescents with Type 1 diabetes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00404081
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of aerial exposure on concentrations of selected metabolites in blood of the Norwegian lobsterNephrops norvegicus (Crustacea: Nephropidae) (1990)
    Springer
    Marine biology 105 (1990), S. 129-135 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The Norwegian lobsterNephrops norvegicus (L.) collected from Firth of Clyde, Scotland between December 1987 and March 1988, was unable to survive longer than 18 h experimental emersion at 10°C. During this time the partial pressure of oxygen (P ν O2) in the venous blood decreased rapidly and the lobster supplemented cellular energy requirements by anaerobic metabolism. This was indicated by the rapid accumulation ofL-lactate in the blood. Although the survival rate increased (to ca 36 to 48 h) if lobsters were kept on ice, the accumulation ofL-lactate in the blood was not significantly different from lobsters at 10°C, despite the temperature difference. There was no indication thatN. norvegicus was able to further metabolize circulatingL-lactate during emersion. On emersion there was also a marked hyperglycemia in the blood due to the stress of handling and asphyxiation. There was fairly good agreement between results obtained during laboratory studies and simulated fishing activity in the Firth of Clyde. Both sets of results are discussed in the context of adaptation to air breathing within the Crustacea and an assesment of post-harvest treatment of lobsters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01344278
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  • 3
    Electronic Resource
    Electronic Resource
    Oxygen-binding by haemocyanins from an ecological series of amphipod crustaceans (1994)
    Springer
    Marine biology 120 (1994), S. 231-237 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The oxygen-binding properties of haemocyanins (Hc) from three species of gammaridean amphipods, Gammarus locusta (L.) (subtidal), Echinogammarus pirloti (Sexton and Spooner), (intertidal, marine) and E. marinus (Leach) (intertidal, estuarine), one species of hyalid amphipod Hyale nilsonni Rathke (high intertidal, marine) and the talitrid amphipod Orchestia gammarellus (Pallas) (semi-terrestrial) have been studied. All the species were collected from the Firth of Clyde, Scotland, during the spring of 1992. The oxygen-carrying capacity of haemolymph from each species was low, although variable, and was correlated with the low concentration of Hc present. The Hc oxygen-affinity of native gammarid haemolymph was relatively high [partial pressure of oxygen required for half-saturation, P50=4 to 5 torr (0.53 to 0.67 kPa)] at their respective in vivo pH values. At equivalent pH, however, Hc from G. locusta displayed a lower O2-affinity than either Echinogammarus species. Gammarid Hcs had a large Bohr effect (Δ log P50/Δ pH=-1.16 to-1.47). Resuspended Hc isolated from whole H. nilsonni showed similar O2-binding properties to those of the gammaridean amphipods [P50=6.3 torr (1.44 kPa) at pH=8.0; Δlog P50/ΔpH=-1.20]. Comparable data for haemolymph from O. gammarellus showed that the Hc had a lower affinity for O2 [P50=14.1 torr (1.87 kPa) at in vivo pH] and exhibited a more moderate Bohr effect (Δ log P50/Δ pH=-0.79). To eliminate the possibility that these differences were due to the different haemolymph constituents, each of the Hcs were pelleted and resuspended in physiological saline. The differences noted above persisted, demonstrating that they were due to inherent O2-binding properties of the Hc molecules themselves. An increase in L-lactate resulted in an increase in Hc oxygen-affinity for both Echinogammarus species but not for O. gammarellus. This study has confirmed that there is a clear difference between Hcs from aquatic and semi-terrestrial amphipod genera. The results lend further support to the hypothesis that the move on to land by amphipod crustaceans is accompanied by a decrease in Hc oxygen-affinity, a decrease in the Bohr effect and a decrease in effector (in this case L-lactate) sensitivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349683
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  • 4
    Electronic Resource
    Electronic Resource
    Mate competition in the velvet swimming crab Necora puber: effects of perceived resource value on male agonistic behaviour (1994)
    Springer
    Marine biology 120 (1994), S. 579-584 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Male velvet swimming crabs [Necora puber (L.)] were observed to engage in long and vigorous agonistic interactions to gain possession of a sexually receptive female. The role of agonistic behaviour in male mate competition in this species was examined by investigating the effect of the perceived presence of sexually receptive females on interactions between males. Exposing male crabs to water conditioned by sexually receptive females resulted in prolonged interactions, with a greater incidence of potentially injurious behaviour than interactions between control crabs, exposed only to sea water. Maleconditioned water also resulted in more offensive behaviour, but these interactions were of shorter duration and not significantly different from sea water controls. Agonistic superiority was strongly correlated with contestant relative size when males were exposed to male-conditioned water or sea water, but not when exposed to female-conditioned water. Overall, the results conformed with the general predictions of game theoretic models in relation to the influence of resource value on agonistic behaviour. Crabs were more persistent and probably incurred greater fitness costs in the perceived presence of a sexually receptive female, when interactions may have been resolved on the basis of factors more closely related to actual fighting ability than the relative body sizes of contestants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00350078
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  • 5
    Electronic Resource
    Electronic Resource
    Comparative study of the effects of temperature, salinity and oxygen tension on the rates of oxygen consumption of nauplii of different strains of Artemia (1993)
    Springer
    Marine biology 117 (1993), S. 623-628 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of temperature, salinity and oxygen tension on the rates of oxygen consumption of three different strains of Artemia nauplii have been studied. When acclimated to a salinity of 30‰, nauplii from each of the three strains were able to maintain approximately constant rates of oxygen consumption over a wide range of oxygen tension. The ability to maintain respiratory independence during hypoxia was reduced, however, with an increase in either temperature or salinity. Nauplii of two of the strains (parthenogenetic diploid and tetraploid) showed a progressive increase in the rate of oxygen consumption with increasing temperature up to 35°C. Nauplii of the bisexual strain appeared to be less tolerant of exposure to temperatures 〉30°C, since at higher temperatures their oxygen consumption declined slightly. The differences between the nauplii of the different strains in their physiological responses to changing environmental conditions appear to correlate well with their seasonal occurrence in the field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349774
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  • 6
    Electronic Resource
    Electronic Resource
    Analysis of 7 polymorphic markers at chromosome 11q22-23 in 35 ataxia telangiectasia families; further evidence of linkage (1990)
    Springer
    Human genetics 〈Berlin〉 85 (1990), S. 215-220 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Ataxia telangiectasia (A-T) is an autosomal recessive disorder characterised by progressive neurological degeneration, oculocutaneous telangiectasia, immunodeficiency and a high incidence of lymphoid tumours. A prerequisite to gaining a complete understanding of the basic defect that results in these features is the localization of the gene(s) involved. We report here a linkage analysis using seven polymorphic markers, which map to 11q22–23, on a sample of 35 consecutively obtained families from the British Isles showing this disorder. In a pairwise analysis, the strongest support for linkage was a lod score of 4.01 at zero recombination from Thy-1. This result supports a previous report showing linkage of the A-T gene to 11q22–23. We have also obtained evidence in a multipoint analysis for a more centromeric A-T-linked locus in the region between YNB 3.12/CJ52.208 and 2-7-1D6. This observation is also supported by inspection of the haplotypes of selected recombinants.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00193199
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  • 7
    Electronic Resource
    Electronic Resource
    Mutational analysis of SRY: nonsense and missense mutations in XY sex reversal (1992)
    Springer
    Human genetics 〈Berlin〉 88 (1992), S. 471-474 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary XY females (n=17) were analysed for mutations in SRY (sex-determining region Y gene), a gene that has recently been equated with the testis determining factor (TDF). SRY sequences were amplified by the polymerase chain reaction (PCR) and analysed by both the single strand conformational polymorphism assay (SSCP) and DNA sequencing. The DNA from two individuals gave altered SSCP patterns; only these two individuals showed any DNA sequence variation. In both cases, a single base change was found, one altering a tryptophan codon to a stop codon, the other causing a glycine to arginine amino acid substitution. These substitutions lie in the high mobility group (HMG)-related box of the SRY protein, a potential DNA-binding domain. The corresponding regions of DNA from the father of one individual and the paternal uncle of the other, were sequenced and found to be normal. Thus, in both cases, sex reversal is associated with de novo mutations in SRY. Combining this data with two previously published reports, a total of 40 XY females have now been analysed for mutations in SRY. The number of de novo mutations in SRY is now doubled to four, adding further strength to the argument that SRY is TDF.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00215684
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  • 8
    Electronic Resource
    Electronic Resource
    The responses of secondary endings of cat soleus muscle spindles to succinyl choline (1994)
    Springer
    Experimental brain research 100 (1994), S. 58-66 
    Details
    ISSN: 1432-1106
    Keywords: Muscle spindle ; Fusimotor Succinyl choline ; Cat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract This report describes the effects of succinylcholine (SCh) on the secondary endings of cat soleus muscle spindles and attempts to explain them in terms of the action of the drug on intrafusal fibres. All but 2 of 41 secondary endings studied in detail showed a significant response to a single intravenous injection of 200 μg kg-1 SCh. This consisted of a rise in the resting rate or development of a resting discharge if the spindle had previously been silent and an increase in the response to stretch. The increases in the responses to stretch were weaker than those observed for primary endings of spindles, but were much larger than those of tendon organs, which showed very little effect with this concentration of drug. The response to SCh showed two features consistent with its action being mediated via an intrafusal muscle fibre contraction rather than a direct depolarising action on the afferent nerve ending. In the presence of SCh, secondary endings were able to maintain a discharge during muscle shortening at rates, on average, more than 5 times greater than under control conditions. Secondly, the increase in spindle discharge produced by SCh showed a length dependence similar to that for fusimotor stimulation. Further support for the action of SCh being principally via an intrafusal fibre contraction was provided by the observation that its effects were abolished by the neuromuscular blocker gallamine triethiodide. The time course of recovery of SCh responses, following their blockade by gallamine, was much slower than recovery of extrafusal tension and closely paralleled that for the recovery of fusimotor responses. In three separate experiments on the medial gastrocnemius muscle the possibility that SCh may exert an excitatory action on spindle sensory endings through the liberation of potassium ions from the muscle was tested by tetanic stimulation of the muscle. This had no detectable excitatory effect. Several observations were made on the effect of SCh on responses of cutaneous receptors. SCh did not change levels of spontaneous activity or responses to mechanical stimulation of either slowly or rapidly adapting mechanoreceptors. It was argued for both tendon organs and cutaneous receptors that if SCh had a direct action on the nerve ending at the concentrations used here, some responses of these receptors to the drug might have been expected. All of the above supports the view that secondary endings of spindles are able to respond to SCh by the development of an intrafusal fibre contracture. The question of the intrafusal fibre types involved is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227279
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of superoxide dismutase on acute reperfusion injury of the rabbit brain (1993)
    Springer
    Acta neurochirurgica 120 (1993), S. 180-186 
    Details
    ISSN: 0942-0940
    Keywords: Blood-brain barrier (BBB) ; cerebral ischemia ; free radicals ; superoxide dismutase (SOD)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To study the involvement of free oxygen radicals of the blood-brain barrier (BBB) disruption during early reperfusion, we isolated the distal internal carotid artery, and the middle and anterior cerebral arteries via the transorbital approach in anesthetized rabbits. Using radiolabeled microspheres, regional cerebral blood flow (rCBF) was measured before, during and after 1-hour unilateral occlusion of these vessels. Fifty-five minutes after ischemia, animals received intravenous saline placebo (control), superoxide dismutase (SOD) at 8mg/kg=30000 U/kg, or weakened superoxide dismutase (wSOD) at 8mg/kg=30000 U/kg. Integrity of the BBB was assessed by leakage of Evan's Bluealbumin dye (EB-albumin dye), which was given at 15 minutes of reperfusion and allowed to circulate for an additional hour. In the control and wSOD-treated groups, rCBF decreased (26% and 40% of control, respectively) within the blue-tinted tissue of the occluded hemisphere during ischemia; hyperemia was observed during early reperfusion. In the control and wSOD-treated groups, EB-albumin dye leakage across the BBB increased 49% within the occluded hemisphere. However, within the SOD-treated group, the BBB showed minimal dye leakage even though rCBF of the occluded hemisphere (so-called blue-tinted tissue) decreased by 38% during ischemia. We conclude that 1-hour focal cerebral ischemia and reperfusion produce a vascular endothelial injury at the BBB. Since SOD administration showed significant protection, free-oxygen-radical production during early reperfusion is associated with break-down of the BBB to large molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02112039
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of antioxidants on the blood-brain barrier and postischemic hyperemia (1994)
    Springer
    Acta neurochirurgica 131 (1994), S. 302-309 
    Details
    ISSN: 0942-0940
    Keywords: Antioxidants ; blood-brain barrier ; cerebral ischemia ; free radicals ; hyperemia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The role of free oxygen radicals in blood-brain barrier (BBB) disruption and postischemic hyperemia was evaluated in the rabbit model of focal cerebral ischemia-reperfusion. Six groups of rabbits underwent clipping of the anterior cerebral, middle cerebral, and intracranial internal carotid arteries. Cerebral blood flow (CBF) was measured by using radiolabeled microspheres, before, during, and 15 minutes after 1-hour occlusion of these arteries. After 50 minutes of ischemia, Group 1 animals (control) received a placebo. Animals in Groups 2–4 received one of three drugs: catalase at 10 mg/kg, methimazole at 5 mg/kg, or indomethacin at 10 mg/kg. A fifth group received a tungsten-supplemented diet for 14 days before ischemia was induced, and a sixth group was sham operated. Microvascular integrity within the brain was determined by the presence or absence of Evan's Blue (EB)-albumin dye leakage across the BBB and was measured by microspectrofluorometry. In the control group during ischemia, CBF dropped to 14%, 7%, and 11% of preischemic levels in rostral, middle, and caudal sections of the brain, respectively, as characterized by extensive EB-albumin dye leakage through the BBB into the ischemic hemisphere. During early reperfusion, postischemic hyperemia was associated with an increase in CBF of 128%, 123%, and 129% of control in the rostral, middle, and caudal sections of the brain, respectively. In all treated groups and in the group receiving a tungsten-supplemented diet, BBB integrity was protected during reperfusion without inhibition of postischemic hyperemia. This study suggests that early disruption of the BBB to large molecules is mediated by free oxygen radicals, which inhibit rather than cause postischemic hyperemia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01808631
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