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West Indian med. j ; 45(suppl. 1): 24, Feb. 1996.
Artigo em Inglês | MedCarib | ID: med-4720


An increased frequency of hypoglycaemic events is commonly observed during pregnancy in intensively treated IDDM patients. It has been speculated upon whether this is due in part to impairment of the hormonal counterregulation. The main aim of this study was to clarify if the hormonal response to hypoglycaemia is modified during pregnancy. Therefore we assessed plasma levels of catecholamines, GH and cortisol as well as subjective symptoms and cognitive functions during a hyperinsulinaemic, hypoglycaemic clamp in the third trimester of pregnancy and 6-12 months after delivery. Venous samples for the analysis of hormones and free insulin were taken every 15 minutes and symptoms of hypoglycaemia were recorded on a visual analogue scale at 30-min intervals. Cognitive functions were studied by a psychological test system at normoglycaemia and at hypoglycaemia. The Wilcoxon signed rank test was used for statistical calcuations. The levels of noradrenaline (mean at hypoglycaemia pregnant 2.30, and non-pregnant 2.44 nmol/l, n.s.) increased the same way on the two occasions, while the adrenaline response was some what higher in the pregnant state (2.09 vs 1.66 nmol/l non-pregnant, p<0.05). The cortisol increase was faster and more pronounced during pregnancy (mean increase 327 vs 130 nmol/non-pregnant, p<0.0001) while the increase in GH was higher in the non-pregnant state (mean increase 23.6 vs 8.7 æg/l pregnant, P<0.0001). We conclude that the present study does not, with the exception of GH, give evidence that pregnancy per se diminishes the counterregulatory hormones response (AU)

Humanos , Feminino , Gravidez , Hipoglicemia/etiologia , Catecolaminas/sangue , Cognição
Comp Biochem Physiol ; 90C(2): 295-303, 1988.
Artigo em Inglês | MedCarib | ID: med-10181


The surface morphology and organization of the neuromuscular system in Cercaria caribbea LXXI are investigated using scanning and transmission electron microscopy, respectively. Direct and indirect (sarconeural) nerve-muscle junctions are identified in the cercarial tail. Synaptic vesicles at the direct neuromuscular junction suggest cholinergic and aminoacidergic transmission. Those at the sarconeural junctions suggest catecholaminergic and/or serotonergic transmission. Acetylcholinesterase and non-specific cholinesterases were found in high concentrations in the proximal and distal tail. Flourescence histochemistry showed primary catecholamines and 5-HT in the body and tail. 5-HT in the tail may represent a slowly depleted store, perhaps associated with energy availability and utilization. (AU)

Parasitos/ultraestrutura , Junção Neuromuscular/fisiologia , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Colinesterases , Aminas Biogênicas , Músculos/anatomia & histologia , Serotonina/isolamento & purificação , Catecolaminas/isolamento & purificação , Fluorescência
Kingston; s.n; Apr. 1986. xxiii,248 p. tab, ills.
Tese em Inglês | MedCarib | ID: med-13624


Scanning and transmission electron microscopy revealed that Cercaria caribbea LXXI has a small body (70 æm) with a pair of well-developed, rhabdomeric photoreceptors; and a large tail (4 mm) with six longitudinal, striated muscle bands. Muscle cells had an outer myofibrillar region adjecent to the tergument and an inner sarcoplasmic region, prolongations of which, may form sarconeural junctions. Sarcomere lengths were consistent with invertebrate fast muscle fibres. Diffuse Z-bands and the presence of numerous mitochondria are consistent with slow muscle fibres, adapted for prolonged work output. Interneuronal junctions with abundant electron-lucent and electron-dense vesicles, and neuromuscular junctions with mainly electron-lucent presynaptic vesicles were demonstrated. The neuromuscular connection between the body and tail appeared to be restricted to a single axon, implying that modulation of tail activity by the body may involve simple triggering or level setting actions, rather than complex modulation. The Falck-Hillarp Formaldehyde-Induced Fluorescence and the Gomori techniques indicated that the neuromuscular system utilizes primary catecholamines, serotonic (5-HT) and an acetylcholine-like transmitter. There were indications that 5-HT promotes activity and is held as a non-replenishable store, depleted through time within the cercarial tail. Exogenous application of a range of neuropharmacological agents, profoundly affected survivorship of the organism. Of the catecholaminergis group, propranolol (1.1-4 æM) and haloperidol (0.066-0.133 mM) most effectively reduced population half-line (T50). This was followed by the cholinergic agent, physostigmine (0.08-2.5 mM). The gamma-aminobutyric acid antagonist, picrotoxin (0.08-2.5mM), only weakly affected T50. Several drugs, especially reserpine (0.08-2.5mM), produced osmotic disturbances, leading to shortened life span. Survivorship was also dependent on pH, with a sharply defined tolerance range between pH 6 and 8. Suction electrodes recordings of electrical activity in the tail revealed spontaneous spike potentials (0.2-0.6 mV, 15-20/sec) superimposed on an underlying slow wave component. The effects of drugs on this activity were observed. 5-HT increased the amplitude and frequency of spike discharge from 0.2 mV to 0.8 mV and 15/sec to 25/sec, respectively. Physostigmine was the most effective reducer of both parameters. Indications were that cholinergic receptors in the nerve network may be excitatory nicotinic and inhibitory muscarinic. Excitatory beta adrenergic and inhibitory dopaminergic influences were observed. C. caribbea LXXI exhibited strong positive phototaxis. In response to light stimuli, the pigmented cercariae gave a maintained receptor potential with a small transient component. In the non-pigmented strain of C. caribbea LXXI, the photosensory receptor potential showed a large transient and a small maintained component. Drugs did not alter the photosensory response. A drug-induced decrease in linear translation towards a photic stimulus was therefore due to a disturbance in the neuromuscular system (AU)

21003 , Parasitos/ultraestrutura , Neurofisiologia , Taxa de Sobrevida , Natação , Microscopia Eletrônica de Varredura/métodos , Junção Neuromuscular/anatomia & histologia , Helmintos/ultraestrutura , Catecolaminas/farmacocinética , Neurotransmissores/farmacocinética , Parassimpatomiméticos/farmacocinética , Serotonina/farmacocinética , Aminoácidos/farmacocinética
Res Commun Chem Pathol Pharmacol ; 45(1): 97-106, July 1984.
Artigo em Inglês | MedCarib | ID: med-9322


Insulin release pattern in vivo was studied using 30 control rats and 30 rats treated with alpha-methyl tyrosine to block catecholamine synthesis in vivo four days before the time of investigation. The drug treated animals exhibited higher fasting insulin levels, and also the phase insulin release after the B cell was challenged with a glucose load was significantly higher in these animals than occurred in the controls. This observation implies that the B cell is modulated by the sympathetic nervous system in its function and the insulin release would vary according to the emotional state of the individual. (AU)

Ratos , 21003 , Masculino , Feminino , Catecolaminas/biossíntese , Insulina/sangue , Metiltirosinas/farmacologia , Tirosina 3-Mono-Oxigenase/antagonistas & inibidores , Jejum , Ilhotas Pancreáticas/metabolismo , Ratos Endogâmicos