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Biomedical subjects

M R Jones

Publications and source records attributed to M R Jones.

At least 181 records · Page 10Linked to original sources
PubMed1979

Memory for symmetry: real or artifact.

Subjects recalled nonrandom digit sequences according to either (a) free recall or (b) a serial recall mode in a series of three studies. Sequential structure was varied with specific rules determining higher-order structure of either (a) arithmetic, (b) symmetrical, or (c) haphazard types. In Experiment I, 18 temporal patterns of 12 digits each were presented visually. Although symmetric patterns were easier than the other two pattern types, this superiority was not determined by recall mode. In Experiment II, 6 temporal patterns of 18 digits each were presented visually, with results similar to those of Experiment I. Auditory patterns equivalent to those of Experiment II were presented in Experiment III. In this study, although the free recall mode produced slightly superior recall with symmetrical sequences, this difference was not statistically significant. It was concluded that superior memory for symmetries cannot be wholly accounted for by organizational strategies made possible by a free recall mode.

Female↗
PubMed1979

Late isolated left ventricular tamponade. Clinical, hemodynamic, and echocardiographic manifestations of a previously unreported postoperative complication.

A unique case of late postoperative left ventricular tamponade, hemodynamically indistinguishable from severe left ventricular failure, is reported in a patient 1 month after an apparently uncomplicated aortic valve replacement. An echo-free space behind the left ventricle led to surgical exploration and successful resolution of the disease process. To our knowledge, this is the first documented case of isolated left ventricular tamponade in the literature. The findings highlight the importance of postoperative echocardiography in the evaluation of the patient having cardiac surgery.

Aneurysm, Infected↗
PubMed1978

Phenylalanine metabolism in uremic and normal man.

The metabolism of phenylalanine and tyrosine was evaluated in six normal men, five chronically uremic men, and three men undergoing maintenance hemodialysis. Phenylalanine, tyrosine, and 13 acidic metabolites of those amino acids were measured in plasma postabsorptively and in plasma and urine after a phenylalanine load of 100 mg/kg. In addition, five normal subjects and five dialysis patients ingested L-[14C]-phenylalanine (uniformly labeled) with the load. In uremic and dialysis patients, plasma phenylalanine rose higher and fell more gradually after the load, and tyrosine rose more slowly. The 24-hr urinary concentrations of phenylalanine and tyrosine were similar in the three groups. At 24 hr, cumulative expiration of 14CO2 was 20.2% in the dialysis patients and 28.4% in the normal subjects. Plasma phenylalanine levels and 14CO2 expiration varied with protein intake in normal subjects. In uremic and dialysis patients, plasma phenyllactic acid, p-hydroxyphenylacetic acid, and p-hydroxybenzoic acid were elevated, the last one markedly so. Moreover, plasma phenylpyruvic acid (PPA) and mandelic acid were detected only in dialysis patients. After the phenylalanine load, plasma conjugated phenylacetic acid rose in uremic patients, and PPA increased transiently in some dialysis patients. In urine of dialysis patients, concentrations of benzoic acid and conjugated o-hydroxyphenylacetic acid were decreased, and PPA was sometimes increased. The data suggest a mild impairment in the hydroxylation of phenylalanine which does not result in marked changes in plasma or in urinary metabolites after a phenylalanine load.

Acetates↗
PubMed1978

Valine metabolism in normal and chronically uremic man.

Valine metabolism was investigated in five normal and three nondialyzed chronically uremic subjects eating 40 +/- SEM 1 and 53 (range 40 to 80) protein diets respectively, in a metabolic research unit. Subjects were injected iv with a tracer dose of L-valine-1-14C while they fasted, and specific activity of plasma valine-14C and expiration of 14CO2 were monitored for two hours. Plasma valine was significantly lower in the uremic patients than in the normal subjects (P less than 0.05). In the uremic patients, specific activity of plasma valine fell less rapidly and remained higher, and expiration of 14CO2 was not different from normal subjects. A two-pool model for valine metabolism was derived which indicated that in uremic patients there was a significant decrease in both valine pools and in the rate of irreversible loss, i.e., valine incorporated into larger molecules, degraded, or excreted. Valine degradation was estimated to be decreased in the uremic patients.

Adult↗
PubMed1978

Thinking.

Explore the source record for details and available documents.

Concept Formation↗
PubMed1978

Fulminant beriberi heart disease with lactic acidosis: presentation of a case with evaluation of left ventricular function and review of pathophysiologic mechanisms.

Cardiac beriberi is considered a rare disease in western society. A patient with fulminant Shoshin-type beriberi was studied in the acute phase and found to have severe metabolic acidosis, high output biventricular failure, and markedly low systemic vascular resistance. Red blood cell transketolase activity was abnormally low. Following treatment with thiamine, diuretics, digitalis and oxygen, all abnormalities disappeared. The historical background of the disease is reviewed along with a discussion of pathophysiologic mechanisms responsible for the hemodynamic profile and lactic acidosis. Angiographic and hemodynamic data on the patient presented suggest relative depression of left ventricular function in the acute phase of beriberi. Since beriberi is uncommonly encountered, emphasis is placed on diagnostic and therapeutic implications of the disease which may not be widely appreciated.

Acidosis↗
PubMed1976

The prevalence of gallbladder disease in patients with ileostomy.

The prevalence of gallstones has been examined in an unselected group of ileostomy patients who had undergone surgery for ulcerative colitis. In this group 11 of 55 patients were found to have gallbladder disease which is an overall incidence of 20%. This is considerably higher than that found in a control population in the same area.

Adult↗
PubMed1976

Infection cycle of Rickettsia rickettsii in chicken embryo and L-929 cells in culture.

The infection cycle of Rickettsia rickettsii, studied in slide chamber cultures of chicken embryo and L-929 cells, was found to be complex and did not conform to a one-step growth cycle. Initial uptake kinetics resembled those established for Rickettsia prowazekii, but subsequent events showed very marked differences. Intracytoplasmic growth commenced exponentially without measurable lag. However, very soon after infection, intracytoplasmic rickettsiae began to escape from the host cell into the medium in large numbers, resulting in (i) failure of large numbers of rickettsiae to accumulate in the cytoplasm, (ii) sustained rapid division of the organisms in the cytoplasm, (iii) substantial accumulation of extracellular rickettsiae, and (iv) rapidly spreading infection in the culture, with most cells infected in 48 to 72 h. In the occasional cell, rickettsiae were found in the nucleus, where they multiplied to form compact masses. Thus, analysis of the growth characteristics of R. rickettsii must consider the entire culture as a unit in which the rickettsiae are distributed among three compartments in which they behave in different ways: (i) intranuclear, (ii) intracytoplasmic, and (iii) extracellular. The rickettsial traffic is bidirectional across the host cell plasma membrane and dominantly monodirectional across the nuclear membranes. The implications of this behavior with respect to location and range of receptors and substrates involved in membrane penetration are discussed. In older cultures, unique intracytoplasmic ring or doughnut colonies were common, indicating a change in the intracytoplasmic environment. The possible significance of the growth characteristics in cell culture to the characteristics of infection in humans and animals is discussed.

Animals↗