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Biomedical subjects

M Peters

Publications and source records attributed to M Peters.

At least 415 records · Page 23Linked to original sources
PubMed1984

Low antithrombin III levels in neonates with idiopathic respiratory distress syndrome: poor prognosis.

Automated microanalytic chromogenic coagulation assays allow serial monitoring of critically ill newborn infants. In this study 84 premature infants [26 healthy prematures and 58 neonates with idiopathic respiratory distress syndrome (IRDS)] were studied daily during the first week of life, to investigate the possible significance of hemostatic abnormalities in IRDS. In neonates with IRDS, coagulation factors II and X, antithrombin III (AT-III), plasminogen, and alpha 2-antiplasmin were significantly lower than control values. Recovery of the initially low AT-III levels was delayed relative to the other coagulation parameters measured. An AT-III less than or equal to 0.15 U/ml was present within the first 6 h of life in eight patients who developed IRDS, seven of whom died within 48 h. Autopsy of these neonates showed widespread fibrin deposition and hemorrhage in vital organs consistent with intravascular coagulation. These findings indicate that very low levels of AT-III are associated with disseminated intravascular coagulation in neonates with IRDS and suggest that a deficiency of AT-III is predictive of a poor outcome.

Antithrombin III Deficiency↗
PubMed1984

Insulin-like growth factor I/somatomedin C (IGF-I/Sm C): comparison of natural, solid phase synthetic and recombinant DNA analog peptides in two radioligand assays.

Investigation of the biologic activity of Insulin-like Growth Factor I/Somatomedin C (IGF-I/Sm C) has been hampered by the scarcity of purified material. The synthesis of this molecule by the solid phase procedure and an analog of IGF-I/Sm C by recombinant DNA technology offers promise that studies of the biologic activity of IGF-I/Sm C will soon be possible. We have found that natural IGF-I/Sm C and the two synthetic peptides behave similarly in two radioligand systems, providing evidence that these molecules possess the requisite structural integrity for use in such biological studies.

Humans↗
PubMed1984

Australian 10-year-olds' perceptions of food. III. The influence of obesity status.

Two studies were conducted which examined the relationships between 10-year-olds' body fat status and their perceptions of foods. The first study of 453 children showed that obese boys linked high-energy foods more to positive consequences, such as growth and satiation, than did slim boys. They also rated bread and potatoes as more fattening than did slim boys. In the second study, one-quarter randomized samples of 40 foods were presented to 500 children, on each of two forms on which the children rated the foods on eight attributes. Results of multivariate analyses showed that obese, average and slim children perceived foods differently along two general themes: (a) properties related to energy, and (b) tastiness-preference. The results are discussed in relation to possible social and physiological causes.

Child↗
PubMed1983

Antigen-specific human B-cell responses: modulation by immunoregulatory T-cell subsets.

In vitro T-cell requirements for and modulation of human B-cell responses were studied in individuals immunized in vivo to the protein antigen keyhole limpet hemocyanin or tetanus toxoid. T cells were required for antibody synthesis in both antigen-driven and pokeweed mitogen (PWM)-driven cultures. T cells were separated into T4+ and T8+ subpopulations using monoclonal antibodies, and their modulation of antibody synthesis was studied. T4+ cells functioned as helper cells in both antigen-driven and PWM-driven cultures in a dose-dependent manner. Whereas T8+ cells suppress both total and specific immunoglobulin secretion in PWM-stimulated cultures, in antigen-stimulated cultures T8+ cells do not suppress unless activated by another cell population present in peripheral blood mononuclear cells (PBMNC). This cellular requirement was further investigated by prestimulation of cells prior to addition to optimally stimulated antigen-driven cultures of PBMNC or B cells, monocytes, and helper T cells. No suppression of these optimally stimulated cultures was seen when T8+ cells were precultured with antigen or PWM. However, after 3-5 days preculture of total T cells with PWM or antigen and then selection of T4+ cells, these cells were able to induce fresh autologous T8+ cells to suppress optimally stimulated antigen-driven cultures. Addition of a precultured mixture of T8+ cells with 20% T4+ cells also resulted in antigen-induced suppression. These data indicate that T8+ cells can suppress antigen-driven cultures but require the presence of preactivated T4+ cells for induction of this suppression of antigen-specific T-cell-dependent human B-cell responses.

Antibody-Producing Cells↗
PubMed1983

Alcoholic hepatitis: granulocyte chemotactic factor from Mallory body-stimulated human peripheral blood mononuclear cells.

The characteristic histopathological features of acute alcoholic hepatitis include hyaline degeneration of hepatic parenchymal cells (Mallory bodies), hepatocellular necrosis, and granulocyte infiltration of the liver. The chemotactic response of neutrophils to highly purified Mallory bodies was studied. Mallory bodies, per se, were not chemotactic for granulocytes, nor did they generate chemotactic factors when incubated with serum. However, a factor(s) chemotactic for both granulocytes and mononuclear cells was generated when Mallory bodies were incubated with mononuclear cells, both from patients with alcoholic hepatitis or from normal controls. It was concluded that Mallory bodies stimulate peripheral blood mononuclear cells to release a factor chemotactic for granulocytes and mononuclear cells. This factor may be important in the etiology of the cellular infiltration in the livers of patients with alcoholic hepatitis.

Acute Disease↗
PubMed1983

Stresses of hospitalization in the elderly: nurses' and patients' perceptions.

A study of stress in hospital is reported. Twenty-five patients (aged 70-93 years) and their nurses were interviewed about the patient's perceived stresses during the first and third weeks of hospitalization. The ward was modern in design and a 'patient allocation' system of nursing care was in operation in which one nurse had primary responsibility for each patient. Patients differed significantly from nurses in their use of a 16-item stress scale, using low scale values rather than high (stressful) values. Although as groups, patients and nurses showed significant correlations between stress ratings over the items, this was interpreted as their sharing common stereotypes about the hospital situation. There was no significant relation between nurses' and patients' ratings of the overall stress being experienced by the patients. An analysis of stress items showed there to be significant differences between type of stress. There was least discrepancy between nurses and patients concerning aspects of physical illness and most on the stressful impact of the hospital environment and routine. While patients rated items within this group (e.g. toiletting) to increase in stress during their stay in hospital, nurses rated the stress value as decreasing.

Aged↗
PubMed1983

Selective activation of antigen-specific human B cells in recently immunized individuals by nonspecific factors in the absence of antigen.

The in vitro effect of nonspecific factors (derived from mixed lymphocyte culture [MLC] supernatants) on human B cell responses was studied in individuals recently immunized in vivo to keyhole limpet hemocyanin, tetanus toxoid, and/or diphtheria toxin. In T cell-depleted fractions of peripheral blood mononuclear cells, nonspecific factors alone, without antigen, selectively induced a specific antibody response to the antigen to which the individual had been recently immunized, at dilutions that did not generate a significant polyclonal response in the remainder of the B cell repertoire. The source of these factors, with respect to MLC donors, did not affect the antibody response. Supernatants of MLC from nonimmunized individuals induced a specific antibody response as effectively as supernatants of MLC from immunized individuals, when added to B cells plus monocytes from recently immunized individuals. Studies in which the same individuals were followed over time showed that these factor-sensitive B cells are seen in the peripheral blood of recently immunized individuals for only a finite period of time. Thus, in vivo immunization with a specific antigen results in the transient appearance in the peripheral blood of B cells that are specific for the antigen in question. These B cells are probably preactivated in that nonspecific factors selectively induce in vitro their further differentiation into antibody-secreting cells, in the absence of added antigen or mitogen. These studies may add further insight into our understanding of the sequential steps involved in the activation and differentiation of human B lymphocytes and provide a model for the combined in vivo and in vitro study of human B cell physiology.

B-Lymphocytes↗
PubMed1982

Rapid microanalysis of coagulation parameters by automated chromogenic substrated methods - application in neonatal patients.

Daily monitoring of coagulation parameters in critically ill premature born neonates is only possible on small amounts of blood obtained by heelpuncture. Therefore, automated spectrophotometric micro-assays for antithrombin III (AT III), factors II and X, plasminogen and alpha 2 antiplasmin were applied on capillary and venous blood samples concurrently obtained in adults and healthy neonates. No statistically significant difference for any of the parameters was revealed. High levels of platelet factor 4 present in serial capillary samples of adults, did not interfere with the heparin dependent AT III assay. There was no evidence of thrombin or thromboplastin generation in these capillary samples, when examined for Va or VII activities. The levels of AT III, factors II and X and of plasminogen in neonates were 35-45% of the adult levels, in contrast to alpha 2 antiplasmin which was in the adult range.

Adult↗
PubMed1982

Interference between concurrent speaking and sequential finger tapping: both hands show a performance decrement under both visual and non-visual guidance.

Report that concurrent speaking reduces right hand sequential finger tapping performance selectively only if the movements are guided non-visually. In these replication experiments, concurrent speaking of both rhyme and prose passages reduced performance both of the right and left hand under visual and non-visual guidance. In the replication experiments the performance of the right hand was slightly more reduced by concurrent speaking than was the case for the left hand. The interference effects are interpreted in terms of the temporal constraints imposed by given motor tasks.

Female↗
PubMed1982

Alcohol unrelated hepato-biliary disorders in the alcoholic: the role of liver biopsy in determining the aetiology of liver disease.

Alcoholics with abnormal liver function tests are generally assumed to have one of the recognised patterns of alcoholic liver injury. This report described a group of nine patients who were initially thought to have alcoholic liver disease but were found on liver biopsy to have a variety of liver disorders unrelated to alcohol. Liver biopsy showed granulomatous hepatitis in three, primary biliary cirrhosis in two, and cholestasis of unknown cause, large duct biliary obstruction, haemochromatosis with secondary carcinoma and Budd-Chiari syndrome in one each. The histological changes observed in liver biopsy samples are believed to represent a chance occurrence of liver disease due to some agent other than alcohol and illustrates that forms of hepatic disease that affect the population at large can and do occur in heavy alcohol consumers.

Aged↗
PubMed1982

Immunocytochemical identity of hepatocellular hyalin in alcoholic and non-alcoholic liver diseases.

Intracellular, eosinophilic, hyaline inclusions (alcoholic hyalin, Mallory bodies) are found in livers of patients with a number of hepatic disorders, although they are most common in alcoholic liver disease. Tissues from patients with primary biliary cirrhosis, jejunoileal bypass, hepatocellular carcinoma, Wilson's disease, and Indian childhood cirrhosis were all positive for hyalin by hematoxylin and eosin staining. Immunocytochemical labeling, using guinea-pig antiserum specific for alcoholic hyalin, was utilized to determine the extent of crossreactivity between hepatocellular hyalin in these various conditions. This antiserum bound to hyalin in fixed paraffin-embedded sections of all liver tissues studied as detected by indirect immunoperoxidase labeling. Binding to normal human liver, however, was restricted to light staining at the surface of hepatocytes. Preimmune guinea-pig serum did not bind to either normal liver or to the test tissues. Our results suggest that hyalin found found in a diverse group of liver conditions represents an immunologically related structure and that its formation may involve a common mechanism.

Adolescent↗