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Biomedical subjects

J D White

Publications and source records attributed to J D White.

At least 163 records · Page 9Linked to original sources
PubMed1982

Hypothermia: the Bellevue Experience.

All adult patients (102 cases) presenting to Bellevue Hospital Medical Center over a calendar year (1978) with core temperatures less than 35 C were studied. Statistically significant correlations between hypothermia and mortality were identified according to mental status, hypoxia, hypotension, hyperamylasemia, duration and severity of hypothermia, and history of exposure and alcohol ingestion. Mortality could not be predicted on the basis of season, age (if greater than 40 years old), sex, presence of infection, or presenting temperature (if greater than 26 C). Thyroid and adrenal function were not significantly altered. Of only nine diabetic patients, four died in ketoacidosis or hyperosmolar states. There were no cases of meningitis, and the incidence of "occult" bacteremia was less than 1%. Prolonged hypothermia was uniformly associated with profound underlying medical disease. In patients presenting with temperatures less than 26 C, 50% of deaths resulted from temperature-induced ventricular arrhythmias. Alcoholics hypothermic from exposure had excellent prognoses; however, temperatures less than 26 C were associated with a marked and statistically significant incidence of death.

Adult↗
PubMed1982

Effect of flunarizine on canine cerebral cortical blood flow and vascular resistance post cardiac arrest.

Twelve dogs were anesthetized and instrumental for determination of CVP, arterial pressure, intracranial pressure, left atrial pressure, and frontal cerebral cortical blood flow (CCBF) by the thermal method. A catheter was introduced into the venous return of the cerebral confluence to allow determination of cerebral A-V oxygen saturation differences. The animals were placed on cardiac bypass using a circuit from the right atrium to the pulmonary artery and a second circuit from the left ventricular apex to the left femoral artery. A heat exchanger was used to maintain a constant blood temperature of 37 C in the output of the left side bypass circuit. All animals were heparinized during bypass. Ventricular fibrillation was induced after completion of the bypass surgery. Two dogs served as controls. Pre-arrest determinations of hemoglobin, glucose, CCBF, and cerebral A-V oxygen differences were taken. Full circulatory arrest was carried out for 20 minutes by shutting off the cardiac bypass. Resuscitation was achieved by resumption of bypass perfusion. Acid-base balance was corrected quickly, and pre-arrest perfusion pressure was achieved and maintained for 90 minutes. All pressure parameters were monitored continuously. All pre-arrest determinations were repeated at 20, 40, 60, and 90 minutes post resuscitation. Five dogs were treated with 6 microgram/kg flunarizine administered IV drip over 10 minutes immediately post reperfusion. Five dogs were not treated post arrest. Treated animals had a prompt return of CCBF rates equal to or greater than pre-arrest flow, which persisted throughout the period of post-arrest observation. Untreated animals had markedly reduced CCBF and increased resistance. CCBF uniformly proceeded to near zero flow by 90 minutes. The ICP was not significantly altered by treatment.

Animals↗
PubMed1982

Canine cerebral cortical blood flow and vascular resistance post cardiac arrest.

seven dogs were anesthetized and instrumented for determination of central venous pressure (CVP), arterial pressure, intracranial pressure (ICP), left atrial pressure (LAP), and frontal cerebral cortical blood flow by the thermal method. A catheter was introduced into the venous return of the cerebral confluence to allow determination of cerebral A-V oxygen saturation differences. The animals were placed on cardiac bypass using a circuit from the right atrium to the pulmonary artery, and a second circuit from the left ventricular apex to the left femoral artery. A heat exchanger was used to maintain a constant blood temperature of 37 C in the output of the left-side bypass circuit. All animals were heparinized during bypass. Ventricular fibrillation was induced after completion of the bypass surgery. Two dogs served as controls for stability of the measured parameters on prolonged bypass. Pre-arrest determinations of hemoglobin, cerebral cortical blood flow, and cerebral A-V oxygen saturation differences were taken. Full circulatory arrest was carried out for 20 minutes in 5 dogs by shutting off the cardiac bypass. Resuscitation was achieved by resumption of bypass perfusion. Acid-base balance was corrected and pre-arrest perfusion pressures were achieved and maintained for 90 minutes. All pressure parameters were monitored continuously. Pre-arrest determinations were repeated at 20, 40, 60, and 90 minutes post resuscitation. A 50% reduction in cerebral cortical blood flow 20 minutes post resuscitation progressed to near zero flow 90 minutes post resuscitation. The changes in net cerebral perfusion pressure produced by the slowly rising intracranial pressure do not account for this flow reduction. Calculation of cerebral vascular resistance reveals a ten-fold increase in resistance post-arrest and -resuscitation.

Animals↗
PubMed1981

Inactivation of mycoplasmas by long-chain alcohols.

In this report, we describe the inhibitory activity of long-chain alcohols on the growth of Mycoplasma gallisepticum and Mycoplasma pneumoniae. Peak inhibition was recorded with saturated primary alcohols (64 microM) varying in chain length from 16 to 19 carbon atoms. The unsaturated alcohols (oleyl, linoleyl, and linolenyl) and the secondary alcohol (pentadecan-2-ol), when employed in the same test conditions, were considerably less effective growth inhibitors than the primary saturated alcohols. Stearic and palmitic acids were also ineffective as growth inhibitors of M. pneumoniae and M. gallisepticum at a 128 microM concentration. Because these antimycoplasma agents are fatty alcohols and cholesterol is known to be required for the growth of some mycoplasmas, additional cholesterol was added in an attempt to reverse the inhibition observed with these agents. Cholesterol at a 128 microM concentration did not significantly relieve the growth inhibition observed with stearyl alcohol at a 48 microM concentration. Mammalian cell cultures were found to be significantly more resistant to the effects of these inhibitory alcohols than were the mycoplasmas. Electron micrographs showed that inclusion of stearyl alcohol in the culture medium produced changes in the cellular morphology of the treated mycoplasmas.

Alcohols↗
PubMed1981

In vitro responses of guinea pig peritoneal macrophages to Legionella pneumophila.

Transmission and scanning electron microscopy were used to study the phagocytosis of virulent and avirulent strains of Legionella pneumophila. The interaction between L. pneumophila and peritoneal macrophages from normal guinea pigs or from animals that had survived infection was studied. The virulent strains survived and proliferated within the phagocyte after ingestion by either type of macrophage, whereas the avirulent strain of bacteria was killed by normal macrophages. Although the addition of immune serum enhanced phagocytosis, the outcome was the same as with normal serum.

Animals↗
PubMed1981

Aerosol Q fever infection of the nude mouse.

Athymic nude mice and euthymic littermate controls were exposed to 10(4) Coxiella burnetii organisms by small-particle aerosol. Antibody response with and without 2-mercaptoethanol treatment of serum was determined at various intervals after infection and serial kills were done to determine morphologic changes in both mouse phenotypes. Total antibody titers determined by the indirect fluorescent antibody technique to phase I and phase II C. burnetii were identical for both groups of mice. Microagglutinin titers determined on days 28 and 33 were abolished by 2-mercaptoethanol treatment of serum from both phenotypes, indicating that the antibody probably resided in the IgM fraction. Microscopically, the reaction to C. burnetii infection was similar in nude and euthymic mice on days 7 and 14. Later, the number and size of lesions attributable to Q fever diminished in euthymic mice. Infection was progressive in nude mice, with macrophage infiltration of most tissues, especially spleen and liver. Numerous rickettsiae were seen by immunofluorescence and electron microscopy in phagocytic vesicles of macrophages, many of which were dilated, giving the macrophage a vacuolated appearance. Results suggest that clearance of C. burnetii infection in mice is independent upon thymus-derived lymphocytes.

Aerosols↗
PubMed1979

Basic mechanisms of lymphocyte recirculation in Lewis rats.

Lymphocyte locomotion in vivo depends upon an intact network of subplasmalemmal contractile microfilaments which are linked through the membrane to surface receptors, and the distribution and stabilization of recognition receptors may be controlled by microtubules and/or 10-nm filaments in the cytoplasm. The differential effects of cytochalasin-A and colchicine on lymphocyte homing and locomotion have proven useful in dissecting the subcellular events underlying the process of lymphocyte recirculation.

Animals↗
PubMed1978

Use of patient data in the control of urea, creatinine and electrolyte estimations.

Analysis of urea, creatinine and electrolyte results from patients in two distric general hospitals is considered as a means of comparing and evaluating laboratory performance in these tests. The raw patient data, consisting of partially overlapping normal and abnormal subpopulations, is analysed by a procedure for resolving overlapping Gaussian distributions. This method permits determination of reference values from hospital populations and in a modified form can also be used to provide a regular indication of the precision of the biochemical estimations. The information derived from such a mathematical treatment of patient results is compared to that obtained from participation in a national quality control scheme.

Computers↗
PubMed1978

The chemiluminescence response of human platelets.

Human platelets and platelet particulate fractions were found to emit a burst of chemiluminescence during incubation with arachidonic acid. The magnitude of light emission was directly related to the number of platelets in the reaction mixture and varied little for the same individual from day to day. The chemiluminescence response of platelets was localized to the particulate fraction and was almost totally oxygen dependent. In addition to arachidonate, seven other polyunsaturated fatty acids, including several that are not prostaglandin precursors, also induced platelet chemiluminescence.A correlation was sought between chemiluminescence and platelet prostaglandin synthesis. Platelets incubated in low concentrations of aspirin, or platelets from subjects who had ingested aspirin, had markedly decreased arachidonic acid-induced chemiluminescence. Salicylic and sulfosalicylic acid had no inhibitory effect. A time-response curve of aspirin inhibition of arachidonate-induced chemiluminescence closely paralleled a time-response curve of aspirin inhibition of malondialdehyde production. Linoleic acid-induced platelet chemiluminescence was also markedly inhibited using aspirin-incubated platelets or platelets from subjects who had ingested aspirin. These studies implicate activation of the enzyme prostaglandin synthetase in the arachidonate-induced platelet chemiluminescence. They provide evidence that linoleic acid may also specifically activate platelet cyclooxygenase to produce electronically excited species capable of light emission.

Arachidonic Acids↗
PubMed1978

Pathology of Bolivian Hemorrhagic fever in the African green monkey.

Gross and microscopic pathological findings are presented for an African green monkey model of fatal Bolivian hemorrhagic fever. Six animals were inoculated with 1,000 plaque-forming units of Machupo virus, the etiological agent of Bolivian hemorrhagic fever. Five of the monkeys died within 13 days with signs of fever, anorexia, shock, and hemorrhage. The sixth monkey survived until the 24th day and died with signs of central nervous system disease. Gross lesions in the five monkeys that die in the acute stage included hepatic necrosis, necrotic enteritis, bronchopneumonia, and hemorrhages in the subcutis, lungs, intestine, liver, and lymph nodes. Microscopically, necrosis was consistently seen in liver, intestine, skin, oral cavity, and adrenal cortex. Acute thrombosis was observed in four monkeys, in blood vessels of the intestine, lung and choroid of the brain. Gram-negative bacteria were seen in many tissues, suggesting terminal bacteremia. The sixth monkey was emaciated and had bronchopneumonia, but did not have the necrotic hepatic and enteric lesions observed in the other five monkeys. The significant microscopic lesions in this monkey included encephalomyelitis, ganglionitis, and bronchopneumonia.

Animals↗