Biomedical subjects
M J Martin
Publications and source records attributed to M J Martin.
Familial pericentric inversion (10) and its effect on two offspring.
A pericentric inversion (10)(p15q24) was observed in three generations of a family. One daughter of the inversion carrier was found to have the inv(10) and trisomy 18. The other offspring had a recombinant (10) chromosome.
Comparison of the effects of Althesin and sodium pentobarbitone on the regional uptake of 2-deoxyglucose by the brain and pituitary gland of the rat: selective effects on pars intermedia.
The uptake of radiolabelled 2-deoxyglucose (2DG) was used to compare the effects of the steroid anaesthetic, Althesin (alphaxalone plus alphadolone acetate) with those of sodium pentobarbitone on the regional metabolism of the brain and pituitary gland. Experiments were carried out on adult female Wistar rats. Studies on conscious animals were carried out with the aid of an indwelling intra-atrial catheter. The uptake of 2DG was measured both by liquid scintillation spectroscopy of 3H-2DG in tissue blocks and by quantitative autoradiography with 14C-2DG. Both anaesthetics significantly reduced uptake of 3H-2DG in the frontal, parietal and occipital cortex, and striatum and thalamus, but 3H-2DG uptake was significantly increased in the pituitary gland. Similar effects were found by measuring 14C-2DG uptake, and this technique showed further that Althesin, but not sodium pentobarbitone, selectively increased (2-fold) the uptake of 14C-2DG by the pars intermedia. The increase in 14C-2DG uptake by the pars intermedia in animals anaesthetized with Althesin was significantly reduced by a lesion placed in the arcuate nucleus. The most likely explanation for the effects of Althesin on the pars intermedia is that this anaesthetic increases the activity of arcuate neurons that innervate the pars intermedia.
Water deprivation results in increased 2-deoxyglucose uptake by paraventricular neurones as well as pars nervosa in Wistar and Brattleboro rats.
The [14C]2-deoxyglucose (2-DG) technique has been used in conjunction with quantitative autoradiography to determine the metabolic activity of the neurones of the hypothalamo-neurohypophysial system. Water deprivation (4 days) in Wistar rats led to a more than two-fold increase in the metabolic activity of the pars nervosa (PN), and a significant increase in the metabolic activity of paraventricular (PVN) but not supraoptic (SON) neurones. The PN in homozygous Brattleboro rats was significantly more active than that in hydrated Wistar and Piebald Virol Glaxo (PVG) rats; as in Wistar rats, activity of the PN and PVN was significantly increased by 12-15 h water deprivation. The administration of desamino-D-arginine vasopressin (dDAVP) to Brattleboro rats significantly reduced the activity of the PN to that seen in hydrated Wistar and PVG rats. This reduction in activity was accompanied by a significant reduction in plasma osmolality. These results show that (1) in contrast to studies in which the osmotic stimulus was a salt load, water deprivation leads to a significant increase in 2-DG uptake by the perikarya as well as the terminals of neurohypophysial neurones; (2) increased activity of the neurohypophysial neurones occurs even when there is a genetic deficiency of vasopressin and the activity can be increased further by an osmotic stimulus, and (3) the activity of the neurohypophysial neurones can be significantly reduced by the administration of dDAVP.
Muscle-contraction (tension) headache.
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A brief review of organic diseases masquerading as functional illness.
A wide variety of physical diseases masquerade as psychiatric disorders. Clinicians may be distracted by a patient's chief complaint of anxiety, depression, or personality change and fail to pursue the possibility of organic disease. The author provides a brief review of physical diseases that produce psychiatric symptoms. He stresses the danger of misdiagnosis and urges clinicians to remain alert to etiological clues during examination, especially when treating patients who have a history of depression, neurotic reactions, or psychosis.
Absence of exercise-induced hypoglycaemia in type i (insulin-dependent) diabetic patients during maintenance of normoglycaemia by short-term, open-loop insulin infusion.
To assess the risk and possible mechanisms of hypoglycaemia during moderate exercise in Type I (insulin-dependent) diabetic patients receiving constant insulin infusion, five insulin-dependent male diabetic patients were exercised 18 h after their last meal and 30 h after their last injection of intermediate acting insulin. Intravenous insulin was initially delivered via a closed-loop infusion system programmed to lower mean blood glucose from 11.3 +/- 1.8 to 4.8 +/- 0.4 mmol/l over approximately 3.5 h. Blood glucose was then maintained at this level for 4 h. At this time, the closed-loop infusion was discontinued and replaced by an open-loop system. The average amount of insulin infused per min during the 4 h normoglycaemic closed-loop period was calculated and this amount was infused at a constant rate during both a 30 min period of exercise on a bicycle ergometer (approximately 65% maximum oxygen uptake) and a 30 min rest period which followed. Five nondiabetic males served as control subjects. Despite significantly higher free insulin concentrations (p less than 0.05) and identical pre-exercise blood glucose concentrations, blood glucose rose during exercise only in the diabetic group (0.5 +/- 0.2 mmol/l; p less than 0.01). Changes in the serum concentrations of lactate, glycerol, glucagon, cortisol, non-esterified fatty acids and growth hormone were similar in the two groups and did not account for the increment of blood glucose in the diabetic patients. Beta-hydroxybutyrate concentrations were, however, higher in the diabetic patients at the onset of exercise (p less than 0.01) and decreased significantly more than the control subjects during exercise. We conclude that exercise under these conditions in diabetic patients is not attended by hypoglycaemia.
A study of the role of the cholinergic system in amygdaloid kindling in rats.
The effect of atropine on kindling the amygdala of rats was tested by administering the drug in a dose of 25 mg/kg 1 h before each stimulus was applied. Rats tested with atropine kindled at the same rate as saline-treated controls. Cholinergic activity in the amygdala of rats was assessed, 4 weeks after the completion of kindling, by measuring both muscarinic receptor numbers and sodium-dependent high affinity choline uptake in tissue homogenates. There was no change in either of these parameters attributable to kindling. These results suggest that changes in the cholinergic system are not fundamental either to the development or the maintenance of kindling in the rat amygdala.
Enhanced rate of kindling after prolonged electrode implantation into the amygdala of rats.
A comparison was made between the rate of amygdaloid kindling in rats which had been implanted with electrodes either 6-8 days or 28-33 days before the start of a series of kindling stimulations. Using both stainless-steel and platinum/iridium electrodes the rate of kindling was significantly reduced after the longer implantation time. Possible mechanisms by which the presence of an electrode in the amygdala may influence the rate of subsequent kindling, and the implications for studies on kindling, are discussed.
Adolescent perspectives on family violence.
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Regional changes in cerebral glucose utilization associated with amygdaloid kindling and electroshock in the rat.
A method using [3H]2-deoxyglucose was used to identify brain areas activated during partial and generalized amygdaloid kindled seizures and generalized seizures following electro-convulsive shock in rats. The amygdala, hippocampus. septal nuclei and hypothalamus were bilaterally activated in kindled convulsions. Electroshock caused a more widespread involvement including the thalamus, striatum, reticular formation and cerebellum. Changes in the amygdala and hippocampus but not hypothalamus, were found after partial kindling.
Patient acceptance of mastectomy for cancer.
Of 300 women who had mastectomy for breast carcinoma, 278 (93 percent) responded to a questionnaire about how well they accepted loss of a breast. Of those responding, 73 percent stated that they had no appreciable adverse reaction to the extent of the operation. Twenty patients (7 percent) cited major work, social or sexual problems resulting from mastectomy. Among the 20, sexual problems--cited by 85 percent--predominated. Four (1 percent) of the 278 patients expressed major dissatisfaction with the cosmetic result of an external prosthesis. Two of these patients and four others had surgical reconstruction of the breast, which was satisfactory in five.
Effects of mild hyperinsulinemia on the metabolic response to exercise.
To assess the effects of mild hyperinsulinemia on the metabolic adaptations to exercise, five normal male subjects were studied during 2 cycles of 30 min rest followed by 60 min mild exercise. During one cycle, insulin was infused at a rate of 0.33 mU/kg/min. During both cycles, plasma glucose concentration was kept constant by a glucose-controlled glucose infusion system. Studies with and without insulin were performed in random order, with 30 min between studies. During the insulin infusion, plasma non-esterified fatty acids fell during rest and failed to rise with exercise, indicating a limited availability of this substrate to working muscle. Insulin infusion also inhibited the expected rise in glycerol and 3-hydroxybutyrate normally observed during exercise. Plasma lactate concentrations at the completion of exercise with insulin infusion were higher than after exercise without insulin infusion. Greater metabolic dependence on carbohydrate metabolism is suggested by an increased respiratory quotient during insulin infusion. Insulin infusion had no significant effect on the amount of glucose which needed to be infused for maintaining a constant plasma glucose during rest, but there was a large and significant difference in the need for infused glucose during exercise with and without insulin infusion. The results indicate that even mild hyperinsulinism interferes with normal metabolic responses to exercise, and suggest that fall in insulin concentration seen with exercise is an important regulatory process, not merely a secondary consequences of a declining plasma glucose level.
Psychiatric problems of physicians and their families.
Motivation for medicine is a complex issue, as is the motivation for other accomplishments in life. There are both conscious and unconscious factors that impel an individual to pursue the long and arduous training necessary to become a physician. Some of these factors meet neurotic needs of the individual and may set the stage for the later development of overt conflicts and psychiatric problems. The most common difficulties of physicians and their families are depression, alcohol and drug dependency, and marital conflicts. These and other issues may involve conflicts concerning unresolved dependency needs. Unfortunately, once problems develop in the physician, attempts at formal evaluation and therapy are often met with denial and resistance. An increased awareness of the problem, and guides for appropriate management of the psychiatrically ill physician by the American Medical Association Council on Mental Health and subsequent legislative changes in a few states, accompanied by an enlightened view by state medical boards, have helped in dealing with this difficult problem. Further, attempts to evaluate impaired physicians objectively and provide helpful and understanding therapy are needed. The prevention of psychiatric difficulties among physicians and their families is an important yet poorly studied area. Likewise, retirement poses special problems for many physicians and efforts should be made by organized medicine to develop educational programs directed toward the prevention of problems at all stages of the professional career.
Antibody-independent complement activation by a subpopulation of mitogen-induced human T lymphoblasts.
A study was made of the complement activation (CA) capacity of human T lymphoblasts obtained in vitro by PHA stimulation of highly purified T cells. The CA was studied by immunofluorescent detection of the C3 fragments deposited onto the cell membrane following incubation in autologous normal human serum (NHS). Whereas resting T cells did not stain, a mean of 12% of the blast cells were positive for monospecific anti-human C3 fluorescent serum. The possible mechanism through which C3 was deposited on the cell membrane may be a consequence of CA, because complement membrane fluorescence (CMF) was abolished by chelation of divalent cations with EDTA, complement inactivation by heating or incubation at low temperature. This reaction appears to occur in the absence of antibodies, because similar results were found when human agammaglobulinaemic serum was used as the complement source. The addition of ethyleneglycolbis-(aminoethylether)-tetraacetate (EGTA), supplemented with MgCl2 to the NHS failed to abolish the fluorescence, indicating that the alternative pathway was involved in the phenomenon. It is likely that the capacity to activate complement may distinguish a functional subpopulation of human T lymphoblasts.
Evaluation of a dip-slide in a university outpatient service.
Initial and followup urine specimens from patients in an outpatient service of a university hospital with the diagnosis of presumptive urinary tract infection were processed by the dip-slide system and the conventional calibrated loop procedure. Evaluation of the dip-slide system included not only microbiological comparison but also the feasibility of the adaptation of this system to a clinic working area. Complete microbiological agreement between the 2 methods was approximately 50 per cent. Disagreement was caused largely by improper inoculation, quantitation and interpretation of the dip-slide. It has been our experience that the dip-slide cannot be used effectively as a screening tool in a population with a high incidence of urinary tract infection. The use of laboratory personnel along with proper specimen collecting instructions increased the reliability of the dip-slide system. Our data suggest that the results obtained should be evaluated carefully along with the clinical impression in complicated cases of urinary tract infections.
Psychogenic factors in headache.
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