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Biomedical subjects

A Peter

Publications and source records attributed to A Peter.

At least 19 recordsLinked to original sources
PubMed1991

Evidence for the extralenticular expression of members of the beta-crystallin gene family in the chick and a comparison with delta-crystallin during differentiation and transdifferentiation.

The beta-crystallins are major water soluble proteins of vertebrate lens fibre cells and have previously been regarded as lens-specific proteins: however beta B2-and beta A3/A1-crystallin RNAs are transcribed and beta-crystallin polypeptides are detectable in the developing chick retina. The beta-crystallin RNA is transcribed in a subpopulation of retina cells and the number of transcribing cells and the level of beta-crystallin polypeptides increase during the differentiation of the retina. Several tissues express beta-crystallin polypeptides, but individual tissues are characterised by qualitative and quantitative differences in the beta- and delta-crystallin polypeptides expressed. The expression of beta-crystallins appears to be non-random as defined by tissue distribution, cellular localisation and ontogeny, implying a function for extralenticular beta-crystallins and a complex mechanism for the regulation of their expression.

Animals↗
PubMed1991

Catecholamine regulation of adipocyte lipolysis after surgery.

The effect of surgical trauma on the regulation of lipolysis was studied in isolated fat cells obtained before and 24 hours after elective cholecystectomy in 12 patients who were not obese and who were healthy otherwise. Surgery was accompanied by a twofold increase of the basal rate of lipolysis and by a significant 50% elevation of the lipolytic effect of catecholamines. The actions of various agents that selectively stimulate lipolysis at different early or late steps in the cyclic adenosine monophosphate system beyond the adrenoreceptors were also increased about 50% after surgery (p less than 0.01). The properties of the beta-adrenoceptors were not altered by surgery, as assessed by radioligand binding and isoprenaline sensitivity. The antilipolytic properties of catecholamines (mediated by alpha 2-adrenoreceptors) were not influenced by cholecystectomy. Lipolysis was not altered in four subjects who had no surgery and who served as control subjects 24 hours after being given the same type of postoperative nutrition as patients who underwent cholecystectomy. We concluded that moderate surgical trauma is associated with increased lipolytic activity of fat cells. This is secondary to an enhanced ability of catecholamines to stimulate lipolysis because of a modification at the most distal steps in the cyclic adenosine monophosphate system, which may involve the protein kinase/hormone sensitive lipase complex.

Adipose Tissue↗
PubMed1989

Differential effects of prenatal exposure to phenobarbital on the behaviour and neurochemistry of CBA and C57BL/6J mice.

Pregnant C57BL/6J and CBA mice were administered 60 mg/kg phenobarbital intraperitoneally from days 10 to 16 of gestation. On day 18 of pregnancy half of the control and drug-treated mice were killed and the embryonic brains removed for cell cultures. The remaining mice were allowed to have their litter. After cross-fostering the mice were used for behavioural studies. Pups born to drug-treated CBA mice had birth-weights similar to controls, but their weights had fallen behind controls by day 18 after birth. They were slower at attaining mature responses in tests for sensory motor development and became progressively more hyperactive (three times more active at day 18) compared to controls. Drug-exposed C57 pups also had birth weights similar to controls. After cross-fostering, 19% of control and 31% of drug-exposed pups died, but the remaining drug-exposed pups showed no deficits in weight gain. In contrast to drug-treated CBA pups, drug-exposed C57 pups were slightly quicker in attaining mature responses in some tests. There was no difference in activity between them and their controls. In neurochemical analyses, uptake of neurotransmitters by cerebral cultures from CBA showed that uptake of GABA was increased by 5%, choline by 95%, dopamine 120%, serotonin 165% and noradrenaline by 160% in cultures from drug exposed embryos compared to controls. In cerebral cultures from C57, GABA uptake was reduced by 18%, choline 33%, dopamine 35% and noradrenaline by 25%. Only serotonin uptake was increased by 182% compared to controls. Differences between C57 and CBA were also apparent in the uptake of neurotransmitters by neuronal cultures from the mesencephalon.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1988

[Effect of flumazenil on global cerebral blood flow and on intracranial pressure in the reperfusion phase following incomplete global cerebral ischemia].

Sedation with benzodiazepines in intensive care patients with head injuries has become part of a standard concept in controlling intracranial pressure (ICP) and metabolic demands of an injured brain. The specific benzodiazepine antagonist flumazenil, which is supposed to exert no direct effect on cerebral blood flow (CBF) in healthy volunteers, suggests that rapid reversal from midazolam sedation might be achieved without any deleterious side effects. It remains however ambiguous if the same holds true in subjects with head trauma. This study describes the effect of flumazenil on CBF, ICP and cerebral perfusion pressure (CPP) during the reperfusion period after incomplete global ischemia in 10 goats. After preparation progressively decreasing CBF in 7 goats was achieved by stepwise external occlusion of the a. max. interna. 90-120 min after reestablishment of CBF 15 mg midazolam i.v. were given followed by 0.5 mg flumazenil i.v. 5 min later. Within 60 sec after application of the antagonist an increase of CBF by 30-165% and of ICP by 25-310% was noted in 5 goats. Simultaneous changes in arterial pressure, CBF and ICP suggest a severe impact of the benzodiazepine antagonist after midazolam sedation on ICP and CBF during periods of impaired cerebral autoregulation. Until the cerebrovascular and cerebral metabolic effects of flumazenil have been elaborated in detail, it is recommended to titrate the effect of flumazenil over long intervals in head injured patients.

Animals↗
PubMed1983

[Reactive dynamics of immunologic parameters in healthy humans and in patients with rheumatoid arthritis].

Investigations of three immune components (IgG, CRP, alpha 1 sGP) in 500 patients with rheumatoid arthritis at the beginning and the end of a spa treatment lasting 4 or 6 weeks as well as in 29 healthy test persons in monthly intervals over 2 years make clear that these immune components represent biorhythmologically regulated functions which underly a different dynamics related to the initial value. By means of the so-called "cross-over-point method" the adequate conditions can be figured. In these cases under the influence of the spa therapy a significant decrease of the dispersion at the end of the significant decrease of the dispersion at the end of the cure develops for the parameters CRP and IgG. These findings as well as the typicality of the course of the empiric regression between the beginning of the cure and the end of the cure represent criteria which are of importance for the demarcation of the dependence of the initial value to a statistical a: (a-b) effect. It is shown that the pathologically reactive dynamics of the immune components can be demarcated from the biorhythmically undisturbed dynamics.

Arthritis, Rheumatoid↗
PubMed1980

[Changes in the immunological components of the blood during balneotherapy in patients with rheumatoid arthritis].

The changes of the immunoglobulin G, the C-reactive protein and the acid alpha 1-glycoprotein which were observed under spa therapy in patients with rheumatoid arthritis. In these cases was shown that these parameters undergo regulative influences which in typical relationship to the initial tissue lead to a cross-over-phenomenon with demarcation of a regulatory zero- (or normal) region. Here patients with rheumatoid arthritis show the tendency to maintain a slightly increased defensive condition under the cure. On the basis of a narrowing of the dispersion of the immune components to the end of the cure compared with the beginning of the cure is concluded that the changes of defensive components to the blood which are to be observed in different initial values are not only based on the endogenic rhythmicity but partly also on the effects of the spa therapy.

Arthritis, Rheumatoid↗
PubMed1979

[Synovial membrane permeability for plasma proteins and protein syntheses in rheumatic diseases].

1. The permeability of the synovial membrane for proteins is larger in rheumatoid arthritis than in osteoarthrosis, in rheumatoid arthritis with high CRP activity larger than in rheumatoid arthritis with low CRP activity. 2. The diffusion by the synovial membrane in most plasma proteins takes place depending on their molecular weight. Of the 14 proteins tested only haptoglobin and fibrinogen did not follow this regularity. 3. While the non-immune proteins proved in the synovial fluid only come from the blood plasma, the immune globulins IgG, IgA, and IgM as well as lysozyme are partly also locally synthetized and enriched in rheumatoid arthritis. In rheumatoid arthritis lysozyme is present in the synovia not only in free, but in most cases also in cell-bound form.

Arthritis, Rheumatoid↗
PubMed1979

Effect of chrysotherapy on parameters of immune response.

Thirty-nine subjects with classical or definite rheumatoid arthritis received weekly intramuscular gold sodium thiomalate (GST) to sustain gold blood levels of more than 320 microgram/dl. Statistical analysis revealed significant declines from pre-treatment values for IgM, IgG, and IaA. Rheumatoid factor titer decreased in 29 of 39 subjects, 15 becoming seronegative. Circulating lymphocytes decreased by 27%. The maximal suppressive effect on IgM was not achieved until the 3rd and 4th years of GST administration. Auranofin (AF) 6 mg/day was administered to 15 patients for an average interval of 45 weeks. In vitro and in vivo suppression of lymphocyte mitogen response with AF was more rapid in onset and significantly greater than with GST. Suppression of dinitrochlorobenzene skin sensitization was observed in AF patients. The clinical response in GST treated subjects correlated with suppression of immunoglobulins, rheumatoid factor titer, and circulating lymphocytes. A significant decline in these variables was not achieved for a corresponding interval with AF treatment. It is suggested that chrysotherapy may be applied more widely to immunologically-mediated disorders and perhaps be used to affect selectively B versus T mediated dysfunction.

Antibody Formation↗
PubMed1976

[Refined diagnosis of C-reactive protein for the detection and course control of chronic inflammatory rheumatic processes].

When different methods of demonstration of C-reactive protein are used, results much deviating one from another may be observed. An exact diagnostics based on radial immunodiffusion with large range of recognition allows a quantitative registration of changes of C-reactive protein. The exact diagnostics of C-reactive protein seems to be of advantage especially with regard to comprehension and control of the course of subclinical processes. Together with the blood sedimentation rate the exact diagnostics of C-reactive protein gives the possibility of an improved objectivation of the process activity in chronic inflammatory rheumatic diseases.

Arthritis, Rheumatoid↗