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Biomedical subjects

R H Murray

Publications and source records attributed to R H Murray.

At least 19 recordsLinked to original sources
PubMed1990

Diffuse pulmonary tumor microemboli from prostatic carcinoma with an associated fibrous histiocytic sarcoma.

Diffuse tumor microemboli to the lungs from prostatic carcinoma are extremely rare, with only six reported cases in the literature published in English. Here a seventh case is reported. The patient resembled the previously reported cases in the following ways: (1) There were minimal chest x-ray findings; (2) there was no other evidence of significant parenchymal or lymphangitic tumor involvement; and (3) pulmonary hypertension developed, but without signs of cor pulmonale. The case was even more unusual because of the presence of an apparent second neoplasm, ie, a malignant fibrous histiocytic sarcoma primary in the chest wall. There were wide-spread "collisional metastases" (metastases from each malignancy at the same site).

Adenocarcinoma↗
PubMed1979

Actively circulating blood volume in endotoxin shock measured by indicator dilution.

To estimate the size of the actively circulating blood volume of splenectomized dogs during control conditions and after endotoxin infusion, the pattern of concentration changes of 51Cr-labeled erythrocytes and 125I-labeled albumin was monitored. A dual exponential equation was fitted to the data. The total red blood cell and albumin volumes of distribution were determined from the slow exponential disappearance curves. The active red blood cell and albumin volumes were 89.8 +/- 5.3% and 92.0 +/- 2.0% of the total volumes, respectively. After endotoxin shock (mean arterial blood pressure 49.1 +/- 17.8 mmHg) the active volumes fell to only 60.0 +/- 10.3% and 56.2 +/- 20.0% of the total volumes, respectively. The fast-mixing time constants were similar (3.1 +/- 1.4 min and 2.5 +/- 2.7 min, respectively) and did not change significantly during the endotoxin shock, indicating that the albumin tag mixed into its larger volume of distribution as rapidly as the cells mixed into their indicated volume. We conclude that 1) an active blood volume can be distinguished, 2) it decreases for both red blood cells and albumin in endotoxin shock, and 3) a major part of the "extravascular plasma volume," as estimated by albumin dilution, is in the actively circulating circulation.

Animals↗
PubMed1976

A calibration system for catheter transducer pressure measurement.

A patient-isolated calibration system is described for use with catheter transducer physiological pressure measuring apparatus. A subatmospheric calibration pressure is applied to the rear of the transducer diaphragm, the latter isolating the patient hydraulic circuit from the calibration system. The calibration system need not therefore be sterile and remains assembled to the transducer table. Risk of air embolus in the patient and of over-pressurising the transducer during calibration are minimised. Simplification of the hydraulic circuit reduces the chance of air entrapment, improving frequency response and reproducability of results and preparation time is greatly reduced. The system is easy to make and has proved simple, rugged and reliable in use.

Catheterization↗
PubMed1970

Idiopathic postural hypotension: physiologic observations and report of a new mode of therapy.

Two patients with severe postural hypotension associated with upper motor neuron and cerebellar impairment (Shy-Drager syndrome) have been studied. Head-up tilt and lower body negative pressure application caused marked falls in arterial pressure; in one patient, paradoxical vasodilatation was observed. Ice application did not increase arterial pressure or calculated forearm vascular resistance. Intravenous atropine in one patient increased heart rate by 18 beats per min, a cardioacceleratory response similar to exhausting recumbent exercise in that patient. 24 hr urinary catecholamine excretion was low, but aldosterone secretory rate was normal in the more severely afflicted patient. A prolonged elevation of plasma renin activity was noted when post-tilt hypertension occurred. When head-up tilt was not followed by this hypertensive period, plasma renin activity response to tilting was normal. Intra-arterial norepinephrine and tyramine both elicited a vasoconstrictor response. Intra-arterial infusions of norepinephrine and tyramine were repeated after administration of the monoamine oxidase inhibitor tranylcypromine. Norepinephrine was potentiated 4.1- and 0.5-fold in the two patients; tyramine was potentiated 3.7-and 1.1-fold in the two patients, respectively. A therapeutic program of tranylcypromine and tyramine (in the form of cheddar cheese) resulted in substantial clinical improvement. It is concluded that in at least some patients with idiopathic postural hypotension, norepinephrine is present in postganglionic sympathetic fibers. A therapeutic program of tyramine and a monoamine oxidase inhibitor may be of value when more conventional modes of therapy fail.

Blood Pressure↗