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Biomedical subjects

M E Berger

Publications and source records attributed to M E Berger.

25 records · Page 2Linked to original sources
PubMed1982

Hypercalcemia in association with a Leydig cell tumor in the rat: a model for tumor-induced hypercalcemia in man.

The etiology of tumor-induced hypercalcemia was investigated in a transplantable Leydig cell tumor of the Fischer rat. In this model, serum calcium rose from a baseline of 10.4 +/0 0.3 mg/dl to 12.5 + 0.4 mg/dl at day 10 and 16.4 +/- 1.3 mg/dl (p less than 0.001) at day 13 post transplant. Urinary calcium also increased from 1.52 +/- 0.17 mg/d to 3.52 + 0.72 mg/d (Day 12, p less than 0.01). Serum phosphate decreased from a baseline of 7.5 +/- 0.3 mg/dl to 5.5 +/- 0.6 mg/dl at day 13 (p less than 0.05). At day 13 serum immunoreactive parathyroid hormone levels fell 76% from baseline (p less than 0.01). Calcitonin increased from 59 +/- 2 pg/ml to 88 +/- 9 pg/ml (p less than 0.02). The plasma prostaglandin E metabolite, 13,14-dihydro-15-keto-PGE2 increased from 407 +/- 103 pg/ml to 647 +/-62 pg/ml (p less than 0.05) and the active Vit D compound 1,25(OH)2D increased from 94.8 +/- 5.2 pg/ml to 162.3 +/- 11.8 pg/ml (p less than 0.01). Urinary cyclic AMP did not decrease in parallel with the parathyroid hormone level and, in fact, increased from 146 +/- 3 nmol/d to 172 +/- 27 nmol/d (NS). Administration of the cyclooxygenase inhibitor indomethacin (20 mg/Kg/d) or hydrocortisone (50 mg/Kg/d) did not prevent the development of hypercalcemia. This model is similar to many patients with humoral hypercalcemia of malignancy who demonstrate suppression of parathyroid hormone with elevated urinary cyclic AMP excretion and may prove useful in the understanding of the responsible mechanisms.

Animals↗
PubMed1981

Prostaglandin and angiotensin converting enzyme inhibition: effect on blood pressure, renin activity and renal function in hemorrhaged conscious rabbits.

The interaction of the prostaglandin and renin-angiotensin systems on blood pressure and renal function was studied in conscious rabbits following mild (6 ml/kg) or moderate (15 ml/kg) hemorrhage. One hour following the injection of the prostaglandin synthetase inhibitor indomethacin (Indo) plasma renin activity (PRA) was significantly lower than the values in control animals. Two hours following hemorrhage, the increase in PRA was very similar in the Indo and control animals. Renal plasma flow (RPF) was not affected by Indo. Glomerular filtration rate (GFR) was significantly lower in the Indo group following moderate hemorrhage. Interruption of the renin-angiotensin system with the converting enzyme inhibitor (CEI), captopril, resulted in similar hypotensive responses in the Indo and non-Indo groups. The marked PRA increase induced by this agent also was not influenced by Indo. The CEI increased RPF and decreased renal vascular resistance (RVR) in the mild hemorrhage animals. However, in the moderate hemorrhage group the RPF changes were variable and RVR tended to increase, especially in the Indo group. GFR fell significantly following captopril in both Indo and non-Indo animals after moderate hemorrhage. The results indicate that prostaglandin inhibition lowers basal PRA levels but that the renin response to hemorrhage and captopril are not prevented. Indo also did not alter the hypotensive response to CEI, suggesting that prostaglandins do not play a major role in this effect. The magnitude of the hemorrhagic stress influences the renal responses to inhibition of the prostaglandin or renin-angiotensin systems in the conscious rabbit.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1981

The medical technologist and the radiation-accident victim.

Radiation accidents may produce external or internal contamination with radionuclides, local or whole-body exposure to penetrating radiation, or a combination of these. Trauma and medical problems which require rapid diagnosis and treatment may accompany a radiation injury. The role of the medical technologist in the early post-injury period may include the use of precautions in handling of contaminated specimens, prompt and repeated determinations of the absolute lymphocyte count, establishment of baseline values of the cellular and chemical components of the blood, and urinalysis. Following significant whole-body exposure to penetrating radiation, laboratory tests are required to monitor the development of granulocytopenia and thrombocytopenia and to provide information necessary for the prevention, control, and treatment of infection and/or bleeding. Chromosome analysis may aid in dosimetry, and a procedure for collecting and shipping blood for analysis by experts in radiation cytogenetics is described.

Diagnosis, Differential↗
PubMedDate not supplied

Dopaminergic modulation of pressor and hormonal responses in essential hypertension.

Hormonal and mean arterial pressure (MAP) responses to posture, isometric handgrip, angiotensin II (AII), adrenocorticotrophic hormone (ACTH), and metoclopramide (MCP), a dopamine (DA) antagonist, were examined in nine men with essential hypertension and nine age- and weight-matched normotensive men on a constant 100 mEq sodium and 80 mEq potassium intake before and after 4 days of administration of the DA agonist, bromocriptine (BEC; 2.5 mg three times a day). BEC depressed supine basal MAP in the hypertensives, and decreased MAP response to posture and isometric exercise in both groups. Hypertensives displayed greater (p less than 0.01) NE responses to posture and exercise than the normotensives. BEC decreased the NE response to 10 minutes of upright posture and exercise more in hypertensives (p less than 0.01) than in normotensives, but following BEC, the responses were similar. BEC did not affect basal PRA or PRA responses to posture and exercise in the two groups. PA responses to ACTH and MCP were similar in both groups, but the hypertensives displayed greater (p less than 0.01) PA responses to AII. BEC suppressed PA responses to AII (p less than 0.01) and to high dose ACTH (p less than 0.05) to a similar extent in both groups. The prolactin as well as the PA response to DA antagonism with MCP was similar in the two groups. These results suggest that dopaminergic control of NE secretion may be altered in essential hypertension. Blood pressure lowering effects of BEC in patients with essential hypertension may be related, in part, to depression of sympathetic nervous system activity.

Adrenocorticotropic Hormone↗