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Biomedical subjects

A Hill

Publications and source records attributed to A Hill.

At least 289 records · Page 16Linked to original sources
PubMed1981

The effect of patent ductus arteriosus on flow velocity in the anterior cerebral arteries: ductal steal in the premature newborn infant.

Marked changes in blood flow velocity in the anterior cerebral arteries, measured by a Doppler technique, have been related to PDA in premature infants. Thus, 55 premature infants of birth weight less than 2,000 gm were studied. Ten developed PDA between days three and ten of life. A sharp decrease in diastolic flow velocity and an increase in pulse amplitude in the ACA was observed with the occurrence of PDA. Return of these values to normal occurred promptly following closure of the lesion. These changes in flow velocity and pulse amplitude in the ACA appear to be determined principally by changes in systemic diastolic pressure which accompany PDA. There was no consistent relationship between the changes in flow velocity and arterial PCO2 values. These data suggest that PDA may be involved in the genesis of ischemic and hemorrhagic cerebral injury in the premature newborn infant. Thus, the decrease in flow velocity appears to represent a "steal" of blood from the cerebral arteries, analogous to other documented steal phenomena observed in older patients. Major fluctuations of blood flow velocity in the ACA, with opening and closure of the PDA, and the increase in amplitude of each pulse with PDA may, in the presence of disturbed autoregulation, cause rupture of the capillaries of the germinal matrix and thus, IVH.

Blood Flow Velocity↗
PubMed1981

Comparison of the Microbact-12E and 24E systems and the API-20E system for the identification of Enterobacteriaceae.

The Microbact-24E and the Microbact-12E systems are two new miniaturized identification systems for the identification of organisms belonging to the family Enterobacteriaceae. These two systems were compared to the API-20E system for the identification of 352 fresh clinical isolates of Enterobacteriaceae. All three systems were easy to use and came complete with computerized profile registers to assist with final identification of the isolates. The Microbact-24E identified 98%, the API-20E and MB-12E identifying 94.3% and 88.6% respectively. Where different identifications were obtained with the Microbact-24E and API-20E conventional biochemical tests, motility and serology were performed. The Microbact-24E system proved to be a very accurate and convenient means of identifying members of the family Enterobacteriaceae.

Bacteriological Techniques↗
PubMed1981

Normal pressure hydrocephalus in the newborn.

The entity of normal pressure hydrocephalus (NPH) following intraventricular hemorrhage in the newborn has been characterized. Of 87 infants with intraventricular hemorrhage, 20 had early and rapidly progressive hydrocephalus with intracranial hypertension and/or death. In 47 cases there was no increase in ventricular size and in 20 cases there was progressive increase in ventricular size with normal intracranial pressure, ie, NPH. Of these infants with NPH, nine had spontaneous arrest with or without resolution of ventriculomegaly, beginning within 31 days of onset. In 11 cases, after a stable period of NPH lasting 12 to 84 days, there was progressive increase in ventricular size accompanied ultimately by raised intracranial pressure. A relationship between the degree of ventriculomegaly and severity of intraventricular hemorrhage was demonstrated. The data thus define a state of NPH after intraventricular hemorrhage and indicate that approximately half of such cases will not develop progressive hydrocephalus with increased intracranial pressure. If arrest or onset of resolution of ventriculomegaly is not apparent within approximately one month, continued progression and necessity for intervention are to be expected. Serial measurements of intracranial pressure and ventricular size in newborns with posthemorrhagic ventricular dilation allow the diagnosis of NPH and permit early recognition of rapidly progressive ventricular dilation with intracranial hypertension which may follow a stable period of NPH. Such early recognition of this potentially harmful state allows prompt ventricular drainage, thereby preventing brain compression.

Cerebral Hemorrhage↗
PubMed1980

Salt-water coupling in leaky epithelia.

The theory of quasi-isotonic transport by cellular osmosis (the standing-gradient theory) has been challenged on the grounds that the osmotic permeabilities of the mucosal and interspace membranes are too low; if they were as high as the theory requires then the osmotic permeability of the whole epithelium would be 2-3 orders of magnitude higher than observed. This objection has basically been accepted for it is now claimed that these enormous permeabilities do exist, but are masked by unstirred-layer effects; I show that this is incorrect because unstirred-layer corrections are small and that the situation has not changed since 1975. The view that the route of fluid transport is junctional is replacing the cellular theory, and trans-junctional water flows seem to account for major fractions of the flow in various epithelia. I argue on grounds of general theory that these are unlikely to be osmotic flows because the junctional pores cannot satisfy both the osmotic and diffusive properties required of them, but the basic osmotic theory is also rather vague here. Non-osmotic theories, if junctional flow is accepted, must be either electro-kinetic or peristaltic.

Animals↗
PubMed1980

The use of levarterenol and phentolamine in patients with low cardiac output following open-heart surgery.

A study was made of the hemodynamic effects of levarterenol and phentolamine in patients in whom low cardiac output developed following open-heart operation. After the patients were weaned from cardiopulmonary bypass, the inotropic agents were infused into an external or internal jugular vein through an IVAC pump. Levarterenol was administered first until systolic arterial pressure rose 20 to 30% above the higest recorded preoperative pressure. After stabilization, phentolamine was administered, and infusion rates were adjusted so that arterial blood pressure was returned to levels measured before bypass. After infusion, all patients showed an increase in cardiac index, mean arterial pressure, mean stroke volume index, and left ventricular stroke work index. Mean pulmonary artery pressure, pulmonary vascular resistance, and left atrial pressure decreased in all patients. This study demonstrates that hemodynamic improvement occurs in humans in low cardiac output state with simultaneous infusion of levarterenol and phentolamine. We recommend these agents for use in patients with low output, unless they continue to receive propranolol during and after operation. Patients on a regimen of propranolol should not be given levarterenol and phentolamine.

Blood Pressure↗
PubMed1980

Analysis of response to ursodeoxycholic acid for gallstone dissolution.

20 patients with radiolucent gallbladder stones were reviewed after 6 months' treatment with ursodeoxycholic acid (UDCA) at a dose of either 500 or 1,000 mg daily. Successful treatment could not be predicted from the patients' characteristics, nor from stone size or pre-treatment biliary lipid analysis. During treatment the bile in patients who responded to UDCA differed from bile in those who did not: mean cholesterol content was lower in responders (4.1 +/- 0.6 vs. 5.7 +/- 0.5 mol%, p less than 0.025) as was the lithogenic index (0.57 +/- 0.06 vs. 0.81 +/- 0.06, p less than 0.005) and the mean UDCA-corrected lithogenic index (0.79 +/- 0.10 vs. 1.04 +/- 0.07, p less than 0.05). However, the individual response could not be predicted from biliary lipid analysis during treatment.

Bile↗
PubMed1979

Osmosis.

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Hydrostatic Pressure↗
PubMed1979

Resumption of treatment with penicillamine after proteinuria.

Penicillamine has been successfully reintroduced and continued for a minimum of 13 months in 5 patients who developed proteinuria during the first course of the drug. The daily maintenance dose during the second course was 150--250 mg taken midway between 2 meals. Proteinuria did not recur; no significant excretion of fibrin degradation products occurred; complement, urea, creatinine, and serum albumin remained within normal limits. Urine microscopy showed no abnormality.

Arthritis, Rheumatoid↗
PubMed1978

[Lethal course of myocarditis successive to polymyositis].

The clinical course and post mortem findings of a 57 year old woman stuffering from polymyositis are reported. Besides the symptoms of the inflammatory musculoskeletal process the myocardial involvement finally gaines importance leading to the fatal outcome. Therefore the indication to early preventive pacemaker implantation is recommended in all cases of myocardial involvement with symptoms of conduction defects.

Adipose Tissue↗