Potentiation of Fas-mediated apoptosis by attenuated production of mitochondria-derived reactive oxygen species

The role of reactive oxygen species (ROS) production in death receptor-mediated apoptosis is ill-defined. Here, we show that ROS levels play a role in moderating Fas-dependent apoptosis. Treatment of Jurkat T cells with oligomycin (ATP-synthase inhibitor) or (mitochondrial uncoupler) and Fas-activating antibody (CH11) facilitated rapid cell death that was not associated with decreased ATP production or increased DEVDase activity and cytochrome c release. However, a decrease in cellular ROS production was associated with CH11 treatment, and combinations of CH11 with oligomycin or FCCP further inhibited cellular ROS production. Thus, decreased ROS production is correlated with enhanced cell death. A transition from state 3 to state 4 mitochondrial respiration accounted for the attenuated ROS production and membrane potential. Similar observations were demonstrated in isolated rat liver mitochondria. These data show that ROS production is important in receptor-mediated apoptosis, playing a pivotal role in cell survival.

Hypoglycemia in hospitalized nondiabetic older patients

OBJECTIVES

To analyze the clinical characteristics, associated risk factors, and outcome of hypoglycemia in nondiabetic hospitalized older patients.

DESIGN

A retrospective case control study.

PARTICIPANTS

Sixty patients, aged 65 years and older, in the acute medical and geriatric wards who developed hypoglycemia. A control group was composed of 83 older patients, sex and age matched, in orthopedic and surgery wards who were undergoing corrective surgery for hip fracture or hernioplasty.

MEASUREMENTS

For all patients, data for the following variables were abstracted from the charts: age, sex, degree of hypoglycemia, clinical presentation of hypoglycemia, number and duration of hypoglycemia episodes, nutritional state, and blood chemistry analysis. Risk factors were defined as nutritional state, heart failure, renal or liver disease, malignancy, and infection or sepsis.

RESULTS

Mean blood glucose in hypoglycemic cases was 38.9 +/- 7 mg/dL. Symptoms and signs of hypoglycemia were noted in only 38.4% (23/60) of patients. All identified risk factors except cachexia were found significantly more frequently in the hypoglycemic patients than in the control group. Mean total number of risk factors was greater in the hypoglycemic group than in the control group, 2.97 +/- 1.1 versus 1.64 +/- .8, respectively (P < .001). In a multivariant logistic model, low plasma albumin level, liver disease, malignancy, and congestive heart failure were significant predictors of hypoglycemia. In-hospital mortality rate was higher among the hypoglycemic patients, 48% versus 18.1% (P < .001), and was independent of the degree of hypoglycemia or the number of hypoglycemic episodes. Mortality was correlated significantly with the number of risk factors (3.4 +/- 1.1 vs 2.5 +/- 1.1; P = .006). Hypoglycemia remained a significant predictor of mortality (OR = 3.67; 95% CI, 1.2-11.2) even after the adjustment for other risk factors.

CONCLUSIONS

Hypoglycemic episodes occur even among nondiabetic hospitalized older patients. Symptoms and signs of hypoglycemia were noted in only two-fifths of the patients. Albumin less than 3.0 g%, liver disease, renal insufficiency, malignancy, congestive heart failure, and sepsis were statistically significant predictors of developing hypoglycemia. The overall mortality rate was significantly higher among the hypoglycemic patients and was independent of hypoglycemia levels. Mean total number of risk factors was significantly higher among those who died compared with hypoglycemic patients who survived. Based on the present study, the estimated odds of mortality in an older patient with hypoglycemia were 3.67 times higher than in those without hypoglycemia.

Thyrotoxicosis and antithyroid drugs

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Single intravenous bolus of dexamethasone for the differential diagnosis of Cushing's syndrome

We developed a 24 hour intravenous dexamethasone suppression test for the differential diagnosis of Cushing's syndrome. Basal ACTH and cortisol levels were measured at 8 and 9 AM; a bolus of 8 mg dexamethasone phosphate (in children 5 mg/m2) was administered intravenously, and cortisol levels were measured hourly until 3 PM, then every 2 hours until midnight, and the next morning at 8 and 9 AM. We studied 13 patients with an ACTH-secreting pituitary adenoma, four with an autonomous adrenal adenoma, a 10 year-old girl with primary adrenocortical nodular dysplasia, one male with an ACTH-secreting medullary carcinoma of the thyroid, and one male with an ACTH-secreting non-small cell carcinoma of the lung, and compared their results to those obtained in 8 lean and 12 obese normal individuals (controls). The clinical diagnosis was first ascertained by the response to the oral administration of dexamethasone in low and high doses (standard Liddle test), then by the intravenous dexamethasone suppression test, and finally confirmed surgically. Although both controls and patients with an ACTH-secreting pituitary adenoma significantly suppressed their cortisol levels within hours after the injection (50% reduction of basal value at 2 hours, and 75% at 4 hours, p < 0.0001), levels remained suppressed the next morning only in the controls, while in the patients they returned to basal values. No suppression was observed in any of the patients with an adrenal adenoma and the child with primary adrenocortical nodular dysplasia (whose ACTH levels were low), or in the patients with ectopic ACTH secretion tumors (whose ACTH levels were high).(ABSTRACT TRUNCATED AT 250 WORDS)

[Pyogenic cervical osteomyelitis following pneumonia]

A 65-year-old man was admitted because of severe cervical pain radiating to both shoulders and bouts of fever, which followed pneumonia. Bone scan showed increased focal uptake in C6-7, while computerized tomography showed destruction of the 7th intervertebral disk, with bone sequesters and soft tissue swelling. Fine needle aspiration drew purulent material with gram-positive bacteria on direct staining. Culture grew Staphylococcus aureus, coagulase positive. Treatment with IV cloxacillin for 3 weeks, followed by oral treatment for another 3, resulted in complete remission.

Compensated hypothyroidism presenting with galactorrhoea

Compensated hypothyroidism was diagnosed in a 36-year-old female who presented with breast tenderness and mild galactorrhoea. T4 was 5.8 mcg dl-1 and T3RU was 22.5%, while TSH and prolactin were very mildly elevated (6.5 mU ml-1 and 26.1 ng ml-1, respectively). The TRH test showed an exaggerated response. TSH increased to 43 mU ml-1, and prolactin levels reached 161 ng ml-1. Treatment with T4 decreased the TSH and prolactin levels to within the normal range, and prevented the galactorrhoea. The case presented here demonstrates that galactorrhoea can be present even with mild hypothyroidism.

Abnormal growth hormone responses to hypoglycemia and exercise in adults with type I diabetes

Abnormal regulation of growth hormone (GH) secretion has been reported in some patients with insulin-dependent diabetes (IDD). We compared the GH responses in 32 healthy subjects (age 25 +/- 2 SE years) and in 23 IDD patients (28 +/- 1.9 years old, diabetes duration 10.4 +/- 2 years, and glycohemoglobin levels 9.3 +/- 2.0%). During acute, severe hypoglycemia (glucose less than 40 mg/dl), the mean GH levels were similar. When prolonged mild hypoglycemia was induced (58.0 +/- 2.0 mg/dl in the controls and 54.0 +/- 2.0 mg/dl in the IDD patients), the mean GH levels were similar, although the increase in GH was delayed in the latter group. During brief (30 min) exercise at 40-50% of VO2max, GH rose comparably in both groups (IDD patients maintained euglycemia with basal insulin infusion). However, with more prolonged and intense exercise using a glucose clamp to maintain euglycemia, GH rose to 5.4 +/- 2.2 ng/ml in controls and 26.4 +/- 12.6 ng/ml in the diabetics (P less than 0.05). When the combination of intense exercise and hypoglycemia (approximately 55 mg/dl) was used, GH rose to a peak of 21.7 +/- 2.7 ng/ml in the controls and to 33 +/- 3.0 ng/ml in the diabetics (P = NS). Our data show that in insulin-infused IDD patients made euglycemic for these experiments: a) The GH response to acute, severe hypoglycemia was identical to that in the controls and the response to mild, prolonged hypoglycemia was delayed, but of similar magnitude compared with controls; b) Exercise-induced GH responses were observed in both groups, but exaggerated in the diabetics at a higher exercise intensity; c) Hypoglycemia during exercise produced an additive effect on GH secretion in the controls but not in the IDD patients. We conclude that the wide range of abnormal GH secretory responses in type I diabetes reflects a central, possibly hypothalamic, defect in GH regulation.

Islet hormonal regulation of glucose turnover during exercise in type 1 diabetes

A decline in plasma insulin and an increase in glucagon are known to occur during intense and/or prolonged exercise. However, it is not established whether changes in insulin and glucagon secretion are involved in the precise matching of hepatic glucose production to the enhanced glucose uptake by muscle during brief, low intensity exercise. We studied the effects of 30-min cycle exercise at 40% of maximal aerobic capacity in healthy subjects and C-peptide-deficient subjects with type 1 diabetes (IDDM) using [3-3H]glucose to estimate glucose turnover. Diabetic subjects were studied during continuous iv insulin infusion, which normalized glucose kinetics before experimental perturbations. In control (saline-infused) experiments, endogenous glucose appearance (Ra) increased by 80-90% above baseline to match the increase in glucose disappearance in both normal and IDDM subjects, even though the latter exercised at fixed levels of plasma free insulin, averaging 203 +/- 19 pmol/L. In other experiments, somatostatin was infused, and glucagon (1.0 ng/kg.min) and insulin (at two different rates) were maintained at constant levels. Infusion of insulin in normal subjects at doses sufficient to maintain constant peripheral plasma insulin was associated with no apparent effect on glucose turnover (plasma insulin, 80 +/- 21 pmol/L, compared to 52 +/- 5 pmol/L during saline; P = NS). However, insulin infusion at doses that normalized the portal insulin concentration (approximately 208 pmol/L) together with glucagon replacement inhibited the rise in glucose production in both normal and IDDM subjects. There were similar 45-55% reductions (P less than 0.03) of the increase in Ra seen with exercise in control experiments. When peripheral plasma free insulin (and presumably portal levels as well) were increased by about 20% in this experimental setting in IDDM (278 +/- 43 pmol/L), the suppression of Ra was even more profound, and Ra failed to increase at all with exercise. We conclude that the hormonal regulation of Ra in brief duration exercise in man does not necessitate the decrements in portal venous insulin observed under more intense exercise conditions as long as an exercise-induced glucagon secretory response can occur. Glucagon secretion alone cannot prevent hypoglycemia when portal venous insulin concentrations are increased by minimal amounts, such as in insulin-treated diabetics.

Regulation of counterregulatory hormone secretion in man during exercise and hypoglycemia

We examined the role of the plasma glucose concentration per se in the secretion of counterregulatory hormones during exercise. Ten men (average age, 24 yr; maximal aerobic capacity, 31.8 mL/kg.min) were studied during two 50-min bicycle exercise periods at either normal glucose [87 +/- 1 (+/- SE) mg/dL (4.8 +/- 0.1 mmol/L)] or low glucose [59 +/- 1 mg/dL (3.3 +/- 0.1 mmol/L)]. The plasma glucose targets were achieved by exogenous insulin and variable glucose infusions. These results were compared to studies in which saline was infused. Exercise at normal glucose was associated with significant increments in plasma epinephrine (maximum 3- to 5-fold above baseline) and norepinephrine (2-fold), comparable to those that occurred during saline administration. Plasma GH increased only at the most intense exercise level, while plasma cortisol and glucagon did not increase significantly. In low glucose-exercise studies, the increase in plasma epinephrine during exercise was significantly greater than that at normal glucose (P less than 0.01), although proportional to basal preexercise levels (r = 0.73; P less than 0.001). Plasma glucagon increased almost 100%, and plasma cortisol and GH increased by 150% and 400%, respectively. Compared to the effect of the same degree of hypoglycemia in the absence of exercise, only plasma epinephrine (P = 0.002) and norepinephrine (P less than 0.001) displayed effects independent of hypoglycemia during exercise. When low glucose was reversed to normal at the midpoint of exercise, plasma epinephrine and glucagon returned to the levels obtained for the same duration of exercise at normal glucose, while norepinephrine, GH, and cortisol were only partially responsive to the rise in plasma glucose. These data suggest that 1) moderate exercise is a stimulus for a sympathoadrenal and GH response, but not a peripheral glucagon response; 2) during exercise and hypoglycemia, plasma epinephrine and norepinephrine are enhanced, while the glucagon response is entirely glucose dependent; and 3) the epinephrine response to hypoglycemia can be dissociated from that to exercise, suggesting differing control mechanisms. We conclude that the activation of counterregulatory hormones during exercise is regulated by glucose-independent mechanisms, although these responses may be augmented by concurrent hypoglycemia.

The effect of prolonged treatment with differing doses of chromium on glucose homeostasis in rabbits

The effect of prolonged treatment with chromium on glucose homeostasis was assessed in rabbits. Thirty-one male rabbits were divided into 6 groups. All were fed for 30 days with a standard ad libitum diet. Twenty-seven rabbits were injected daily during a further 120 days with different doses of potassium chromate (3-20 micrograms) while 4 rabbits served as controls. No significant rise in serum glucose levels was observed, insulin levels were the same in the different groups, and glycosylated hemoglobin concentration also did not change after the administration of chromium. Serum chromium levels increased proportionally to the dose injected to an almost a 14 fold increase in the 20 micrograms chromium treated group. Although others have shown that chromium may have a hyperglycemic effect with inhibition of insulin secretion, we have not been able to confirm this finding.

Improved renal function following acute peritoneal dialysis in patients with intractable congestive heart failure

Nine patients, six men and three women, 40 to 73 years of age, were included in the study. All of the patients had severe heart failure refractory to aggressive therapy including digitalis, diuretics, and vasodilators. Eight patients underwent one treatment of peritoneal dialysis while the remaining patient received two dialyses. The urine output was measured by an indwelling catheter; glomerular filtration rate (GFR) was determined by creatinine and inulin clearance, and renal blood flow (RBF) was determined by sodium paraamino hippurate (PAH) clearance. Following one peritoneal dialysis, the mean fluid loss/patient was 3,995 ml (range 3,200 to 5,100 ml). Dialysis was generally well tolerated. One patient, who had underlying hepatic cirrhosis and underwent two dialyses, developed hepatic failure and died 10 days after the second dialysis. At postmortem, peritonitis was discovered. All of the patients showed a marked subjective and objective clinical improvement. The mean plasma urea decreased from 154 to 71 mg/dl (P less than 0.005), and mean plasma creatinine decreased from 1.83 to 1.13 mg/dl (P less than 0.005). Blood pH was 7.30 before dialysis and increased to 7.37 (P less than 0.0125) after treatment. Mean urine output predialysis was 955 ml and increased to 1,472 ml post dialysis (P less than 0.0005). Creatinine clearance increased from 35 to 73 ml/min (P less than 0.0005). The mean inulin clearance increased from 33 ml/min predialysis to 69 ml/min post dialysis (P less than 0.0005), and mean PAH clearance increased from 96.7 to 362.5 ml/min (P less than 0.0005). Acute peritoneal dialysis is a safe and effective means for removing large quantities of excess fluid from patients with intractable heart failure.

Beta-adrenergic contribution to glucagon-induced glucose production and insulin secretion in uremia

Spontaneous or propranolol-induced hypoglycemia can occur in uremic humans. We studied glucose kinetics (using [3-3H]glucose) in five uremic humans 24 h after hemodialysis and in seven normal controls. The effect of glucagon infusion at rates of 3, 6, 12, and 18 ng X kg-1 X min-1 at 60-min intervals was compared with either saline or beta-adrenergic blockade (propranolol infusion). In uremics, plasma glucose increased by 20-25% and by 40-50% at the 3 and 6 ng X kg-1 X min-1 glucagon doses, respectively, with no further increases at higher infusion rates. Glucose production increased transiently and in tandem with glucose uptake at each glucagon increment (P less than 0.0001). During beta-adrenergic blockade, the effect of glucagon in stimulating glucose production was blunted by 14-24% at the 6-18 ng X kg-1 X min-1 doses (P less than 0.05). During saline infusion, plasma insulin concentrations increased progressively to peak levels fourfold above basal at the 18 ng X kg-1 X min-1 dose. This increase in plasma insulin was virtually abolished by concomitant beta-adrenergic blockade (P = 0.0002). In contrast to uremic subjects, normal controls exhibited lesser degrees of hyperglycemia and hyperinsulinemia at all glucagon infusion rates. Propranolol infusion had no effect on the increments in glucose production and uptake nor on the plasma insulin response. These results suggest that in uremic humans propranolol independently reduces the hepatic response to glucagon and the insulin secretory response to hyperglycemia and/or hyperglucagonemia. These observations provide a possible mechanism for the adrenergic regulation of glucose homeostasis in uremia.

Iodine-induced hyperthyroidism in a patient with a normal thyroid gland

Iodine-induced hyperthyroidism can develop even in the presence of an otherwise normal gland. One of the less common sources of iodine is tablets of seaweed, sold over the counter without prescription. We report the case of a 72 year old female who developed clinical and laboratory evidence of hyperthyroidism while ingesting sea-kelp (Vitalia) tablets. Six months after stopping the tablets, the symptoms and laboratory evidence of hyperthyroidism had disappeared. No evidence of pre-existing thyroid disease was found.

Evolution of hypothyroidism in familial goitre due to deiodinase deficiency: report of a family and review of the literature

We studied two sisters who developed large non-toxic goitres in adolescence. Deiodinase deficiency was diagnosed by a rapid thyroid uptake of radioactive iodine (RAI) at 2 hours associated with a marked fall in thyroidal 131I by 24 hours. Serial RAI scans in the second patient documented evolution of the iodine-deficient state. Conservation of intra-thyroidal iodine stores was maintained by avid iodine uptake and failure to release organified 131I. With progressive loss of inorganic iodine, hypothyroidism developed, associated with a rise in serum TSH which further exacerbated the loss of iodine. Treatment with L-thyroxine resulted in an improvement of thyroid function, but normalization was achieved only after small doses of Lugol's iodine were administered. These studies illustrate the variable nature and late onset of an inborn error of thyroid metabolism. This family supports an autosomal recessive mode of inheritance for deiodinase deficiency. We have documented progression from a euthyroid to hypothyroid state resulting from decompensation of iodine conservation mechanisms.

Glibenclamide induced prolonged hypoglycaemia

Prolonged hypoglycaemia (serum glucose levels of 50 mg/dl and less, for more than 12 h in spite of treatment with periodic injections of hypertonic glucose) secondary to treatment with glibenclamide was found in 13 hospitalized patients. The mean daily dose of glibenclamide was 6.7 mg. In nine patients, the hypoglycaemia developed within 7 days of treatment. In two patients the tendency to hypoglycaemia lasted for more than 60 h in spite of continuous infusion of 5% or 10% glucose. Old age seems to be a crucial predisposing factor as none of the patients was under the age of 68 years. Contributing factors were renal failure and congestive heart disease. We feel that glibenclamide should be used with care in the elderly and in patients with renal or cardiac failure.

Histomorphometric evaluation of reversible heparin-induced osteoporosis in pregnancy

Transilial bone biopsy confirmed heparin-induced osteopenia in a 23-year-old postpartum patient. Histomorphometric measurements during the reversible stage of bone disease that followed discontinuation of the heparin sodium therapy revealed signs of recovery; these were superimposed on a loose trabecular structure typical of osteoporosis. The histomorphometric evidence of recovery correlated well with signs of clinical improvement. In the majority of patients, heparin therapy during pregnancy is innocuous; however, discontinuation of treatment is recommended at the earliest signs of osteoporosis.

Atrioventricular and sinoatrial block in thyrotoxic crisis

A 55 year old woman in thyrotoxic crisis developed atrial fibrillation, atrioventricular block, and sinoatrial block in rapid succession. All of these abnormalities resolved completely after antithyroid treatment. This course of events illustrates the profound effect of thyroid hormones on cardiac function. In view of the potential aggravation of atrioventricular conduction disturbance by beta adrenergic blocking agents, thyrotoxic patients should be carefully screened for electrocardiographic evidence of conduction disturbance before the administration of such drugs.

Chronic cutaneous polyarteritis nodosa simulating recurrent thrombophlebitis

A 30-year-old man who had 12 repeated hospital admissions within a period of 7 years for localized pain and swelling of the extremities is described. Excision biopsy of several subcutaneous lesions revealed histologic changes typical of polyarteritis nodosa (PN). Systemic disease was excluded because of a normal testicular biopsy, negative abdominal angiogram, and the lack of evidence for renal or other visceral involvement. Response to steroid therapy was excellent. Cutaneous PN is a distinct subset of polyarteritis with a chronic course and excellent prognosis. The present case underlines the need for a greater awareness, and for considering early biopsy of suspected lesions in patients with multiple episodes of apparent superficial thrombophlebitis.

Acute hemolytic anemia caused by severe hypophosphatemia in diabetic ketoacidosis

Hypophosphatemia in diabetic ketoacidosis is well recognized, but is believed to be usually of moderate severity. We describe 2 patients in whom acute hemolytic anemia secondary to severe (0.19-0.35 mmol/l) hypophosphatemia has developed 1-2 days following treatment for diabetic ketoacidosis. Our experience indicates that severe hypophosphatemia requiring phosphate supplementation does occur in diabetic patients, and calls for increased awareness for the clinical and laboratory manifestations of this complication of diabetic ketoacidosis.

Effect of non aromatizable androgens on LHRH and TRH responses in primary testicular failure

We have assessed the gonadotropin, TSH and PRL responses to the non aromatizable androgens, mesterolone and fluoxymestrone, in 27 patients with primary testicular failure. All patients were given a bolus of LHRH (100 micrograms) and TRH (200 micrograms) at zero time. Nine subjects received a further bolus of TRH at 30 mins. The latter were then given mesterolone 150 mg daily for 6 weeks. The remaining subjects received fluoxymesterone 5 mg daily for 4 weeks and 10 mg daily for 2 weeks. On the last day of the androgen administration, the subjects were re-challenged with LHRH and TRH according to the identical protocol. When compared to controls, the patients had normal circulating levels of testosterone, estradiol, PRL and thyroid hormones. However, basal LH, FSH and TSH levels, as well as gonadotropin responses to LHRH and TSH and PRL responses to TRH, were increased. Mesterolone administration produced no changes in steroids, thyroid hormones, gonadotropins nor PRL. There was, however, a reduction in the integrated and incremental TSH secretion after TRH. Fluoxymesterone administration was accompanied by a reduction in thyroid binding globulin (with associated decreases in T3 and increases in T3 resin uptake). The free T4 index was unaltered, which implies that thyroid function was unchanged. In addition, during fluoxymesterone administration, there was a reduction in testosterone, gonadotropins and LH response to LHRH. Basal TSH did not vary, but there was a reduction in the peak and integrated TSH response to TRH. PRL levels were unaltered during fluoxymesterone treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

The interrelationships between prolactin and thyrotrophin secretion following dopaminergic blockage in patients with mild hyperprolactinaemia without any demonstrable pituitary tumour

PRL, TSH and gonadotrophin responses to the dopaminergic antagonist, metoclopramide, were studied in mildly hyperprolactinaemic patients with normal sella radiology and CT scan. Eleven female patients with basal PRL levels ranging from 23 to 124 ng/ml were challenged with intravenous metoclopramide (10 mg) and on subsequent occasions with TRH (200 micrograms) and LHRH (100 micrograms). On the basis of the PRL secretory pattern following metoclopramide and TRH stimulation, the patients were divided into two groups. Group I comprised six subjects who were PRL non-responsive to TRH and metoclopramide. Group II (five subjects) demonstrated PRL responses to TRH and metoclopramide indistinguishable from female controls. Mean +/- SD basal PRL levels were 68.5 +/- 29.9 ng/ml in Group I and not different in Group II (40.6 +/- 12.0 ng/ml). Basal LH levels were increased in Group II, whereas FSH was increased in Group I. Basal TSH levels were lower in Group I than the controls. Following metoclopramide, Group I patients had an increase in TSH from a basal of 2.4 +/- 0.7 microU/ml to a peak of 5.9 +/- 2.7 microU/ml (P less than 0.005) which occurred at 30 min. TSH values were increased above basal at all time intervals following metoclopramide. In contrast, TSH levels did not change in Group II patients or the controls after metoclopramide administration. Both patient groups had TSH responses to TRH similar to the controls. Following LHRH, the LH increase was greater in Group II and the FSH in Group I. In neither group nor the controls did gonadotrophin levels change after metoclopramide. In Group II females, PRL responsiveness to metoclopramide was associated with TSH non-responsiveness. In Group I females, PRL levels failed to rise, whereas TSH increased. The PRL and TSH profile in Group I females is typical of a prolactinoma. It is concluded that PRL as well as TSH determinations following metoclopramide are useful indices in the assessment of hyperprolactinaemia and may be of value in differentiating the functional state from that of a pituitary tumour.

Transient methimazole-induced bone marrow aplasia: in vitro evidence for a humoral mechanism of bone marrow suppression

A patient with methimazole-induced aplastic anemia is described. Despite severe pancytopenia and the complete disappearance of hemopoietic elements from the bone marrow, recovery of hemopoiesis has been observed within 14 days of discontinuing methimazole therapy. In vitro studies of CFU-C inhibition of peripheral mononuclear cells harvested in remission, were performed by incubation with autologous sera collected at earlier phases of the disease. These studies provide evidence in favor of a humoral, and most probably autoimmune mechanism as the cause of transient bone marrow aplasia.

Increased prolactin response to thyrotropin-releasing hormone in primary ovarian failure

To investigate prolactin (PRL) and thyrotropin-stimulating hormone (TSH) secretion in ovarian failure, 14 women with primary ovarian failure were challenged with luteinizing hormone-releasing hormone (LHRH) (100 micrograms) and thyrotropin-releasing hormone (TRH) (200 micrograms) given intravenously at 30-minute intervals. Responses were compared with those of 13 healthy female controls. In the patient group, basal follicle-stimulating hormone (FSH), LH, and peak gonadotropin responses to LHRH were higher and basal estrone and estradiol levels were lower than in the controls (P less than .001). Mean basal PRL levels were similar in the 2 groups. However, the mean peak and integrated PRL responses in the patients were greater than in the controls (P less than .05). Ten patients had a markedly exaggerated PRL response to TRH. The mean basal TSH levels and the peak TSH response to TRH were similar to those of the controls. Estrogens are known to stimulate PRL secretion. These subjects had increased PRL responses with low circulating estrogens. The mechanism underlying the findings is not known, but could be related to increased aromatization of androgens to estrogens in the hypothalamus. Alternatively, other factors could be responsible for the exaggerated PRL responses to TRH noted in these patients with primary ovarian failure.

Clomiphene citrate does not modify the exaggerated thyrotrophin response to thyrotrophin-releasing hormone occurring in primary testicular failure

Patients with primary testicular failure have increased basal TSH levels and an exaggerated TSH response to TRH in the presence of normal circulating levels of thyroid hormones. In order to evaluate it this TSH profile is an oestrogen-related phenomenon, sixteen patients with primary testicular failure were challenged with 200 micrograms TRH prior to and after the administration of clomiphene citrate. The latter was given in a dose of 100 mg/day for 4 weeks to ten patients; 200 mg/day for 4 weeks to three patients and 100 mg/day for 2 months to the final three patients. The patients demonstrated increased mean basal TSH levels with an exaggerated TSH response to TRH. Following the administration of clomiphene citrate, there were no changes in T4, T3 sephadex or total T3 levels and in basal or stimulated TSH levels. Clomiphene did produce an increase in oestradiol, testosterone, basal gonadotrophins and LH response to LHRH. Since the oestrogen antagonist, clomiphene citrate, had no effect on TSH secretion, it is unlikely that the exaggerated TSH response to TRH is mediated by oestrogens.

Hypertransaminasemia with subcutaneous heparin therapy

An elevation of serum aspartate aminotransferase (GOT) and alanine aminotransferase (GPT) may be produced in patients treated with i.v. full-dose HEPARIN. We studied the influence of low-dose s.c. HEPARIN (5,000 IU X 2) in 34 patients with acute myocardial infarction (AMI) and in 7 with cerebrovascular accidents or calf thrombophlebitis. Twelve patients (all males) with AMI showed a secondary elevation of GOT and GPT at about the sixth or seventh day after the commencement of therapy that persisted throughout the period of treatment. Four patients (two males and two females) with cerebrovascular accidents or thrombophlebitis showed similar increases of GOT and GPT.

Prolactin response to metoclopramide and chlorpromazine in primary testicular failure and isolated gonadotrophin deficiency

The aim of the present study was to measure the PRL response to metoclopramide (MET) and chlorpromazine (CPZ) in seventeen patients with primary testicular failure and eight patients with isolated gonadotrophin deficiency (IGD). The responses were compared with those to TRH. Basal gonadotrophins and peak responses to LHRH were increased in testicular failure and reduced in IGD. Basal PRL levels were normal in both groups of patients. However, when compared with controls, the PRL response to both MET and CPZ as well as to TRH was exaggerated in primary testicular failure, whereas the responses wee decreased in IGD. In both patient groups, as well as in the controls, the PRL response to MET exceeded that to TRH and CPZ. It is suggested that alterations in the steroid milieu are responsible for the exaggerated PRL response to MET, CPZ and TRH in primary testicular failure and the reduced response observed in IGD.

Astigmatism of the mammalian cornea: evolutionary and perceptive significance

Astigmatism enables spatial, linear and directional discrimination. These faculties are demonstrated by astigmatic photographic experiments. Comparative anatomic deductions lead to the assumption that the eyes of early mammals were astigmatic. Thereby these animals, lacking binocularity and accommodation, could achieve visual spatial information. This assumption is supported by the fact that features of astigmatic refraction, specially straight linearity, have been adopted by various intra-ocular structures, and by the neuronal structuralisation of receptive fields in the visual cortex of mammals.

A trichromatic test for spheric and astigmatic refraction

An improved chromatic rotatable refraction test for simultaneous spheric and astigmatic refraction is described. Its new features are interposition of a bright yellow stripe between the conventional red and green fields and a pair of parallel test lines, which traverse vertically all colored fields. Thereby astigmatic errors become easily visible.