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Biomedical subjects

G Biro

Publications and source records attributed to G Biro.

At least 19 recordsLinked to original sources
PubMed1998

Lipid status in adolescents born with low birth weight.

The study compared anthropometric parameters and lipid status of adolescent boys and girls (14-16 y) born with LBW or ABW. Values for body weight and height of LBW adolescents were lower than those for ABW's. BMI differed significantly between LBW and ABW boys. In LBW boys, serum LDL-C level was somewhat lower, and the ApoA1 concentration was higher than in ABW's. Other lipid parameters did not differ among the corresponding groups. These data suggest that hypercholesterolemia, which is seen in LBW adults, must develop in older ages, and the irregular lifestyle including improper nutritional habits may promote its occurrence in this vulnerable group.

Adolescent↗
PubMed1994

Elimination of an artificial immune complex by plasmapheresis in rabbits.

The behaviour of an artificial immune complex was investigated in 15 rabbits. The immune complex was labelled with iodine-125 (125I). The advantage was that the immune complex could not be metabolized without being eliminated by the kidney. This artificial immune complex was injected in different dosages (0.8 micrograms-40 micrograms/rabbit) on 2 consecutive days. One group (n = 9) was treated with plasmapheresis: the other (n = 6) was a control group that did not undergo plasmapheresis. A miniaturized plasmapheresis system eliminated the immune complex very effectively. The increasing concentration of the immune complex in the blood before the next plasmapheresis treatment was probably an expression of mobilization of the immune complex from different organs. The animals of the plasmapheresis group were in better condition than the control group.

Animals↗
PubMed1993

[The behavior of the stress hormones cortisol, somatotropin (STH) and prolactin during anesthesia induction with midazolam-alfentanil in comparison with thiopental].

In the present study, not only circulatory parameters but also serum concentrations of the stress hormones cortisol, Somatotropin and prolactin after endotracheal intubation were determined during narcosis. In 19 patients undergoing neurosurgical vertebra disc operations, general anaesthesia was induced with midazolam and alfentanil, while a control group of 8 patients was given thiopentone. The stress hormones were determined by radioimmunoassay immediately prior to and 1, 3 and 6 minutes after intubation. The induction of anaesthesia with the combination midazolam-alfentanil resulted in considerably fewer alterations of hemodynamic parameters such as arterial blood pressure and heart rate than the induction with thiopentone in both groups could be observed. A direct effect of thiopentone and midazolam on prolactin release could be excluded in a comparative study in which comparable amounts of these substances were administered without intubation. After alfentanil a slight, insignificant rise in the prolactin level occurred. Evaluation of such a short stimulus as endotracheal intubation by so-called stress hormones has not yet been satisfactorily achieved.

Alfentanil↗
PubMed1992

Elimination of an artificial immune complex by plasmapheresis in rabbits.

The behavior of an artificial immune complex was investigated in 15 rabbits. The immune complex was labeled with iodine-125 (125I). The advantage was that the immune complex could not be metabolized without being eliminated by the kidney. This artificial immune complex was injected in a dosage of 0.8 microgram, in 2 rabbits, 5.0 micrograms in 4 rabbits, 10 micrograms in 3 rabbits, 20 micrograms in 2 rabbits, and 40 micrograms in 4 rabbits on two consecutive days. One group (n = 9) was treated with plasmapheresis: the other (n = 6) was a control group that did not undergo plasmapheresis. A miniaturized plasmapheresis system eliminated the immune complex very effectively with an average exchange volume of 95.7 ml per treatment. The increasing concentration of the immune complex in the blood before the next plasmapheresis treatment was probably an expression of mobilization of the immune complex from different organs. The animals of the plasmapheresis group were in better condition than the control group.

Animals↗
PubMed1992

Inappropriate vasopressin secretion in severe alcohol withdrawal.

Forty-one male alcoholics suffering from alcohol withdrawal syndrome were investigated to assess the relationship between vasopressin (ADH), water homeostasis and alcohol withdrawal. During 10 d, we found a significant decrease in serum vasopressin, from 3.08 +/- 0.61 to 1.71 +/- 0.22 pg/nl. There were no concomitant changes in osmolality, so that a general dysregulatory state of vasopressin secretion during alcohol withdrawal cannot be assumed. Only patients with delirium tremens (8/41) had higher vasopressin levels despite lowered serum osmolalities. These findings support the hypothesis of an inappropriate rebound secretion of vasopressin in severe alcohol withdrawal. Furthermore, they may contribute to the pathogenesis of focal alcoholic brain damage, because rapid and/or profound changes in osmolality are suspected to cause circumscribed cerebral demyelinization.

Adult↗
PubMed1992

Hypomagnesaemia-induced hypocalcaemia: concentrations of parathyroid hormone, prolactin and 1,25-dihydroxyvitamin D during magnesium replenishment.

Three patients with hypomagnesaemia-induced hypocalcaemia were investigated during the phase of magnesium replenishment. Before treatment, serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were at the lower limit of normal. In spite of a rapid rise of parathyroid hormone (PTH) after intravenous administration of magnesium, a reactive increase in 1,25-dihydroxyvitamin D in serum was absent or delayed. The increase of serum calcium into the normal range occurred before any consistent change in the concentrations of this vitamin D metabolite. The rise of serum prolactin in response to the increase in PTH was blunted or absent, and is a further example of a transient PTH resistance during the phase of magnesium replenishment.

Alcoholism↗
PubMed1992

Mechanisms of hypocalcaemia in the clinical form of severe magnesium deficit in the human.

Severe magnesium depletion leading to hypocalcaemia has been described in a variety of clinical settings. Inadequately low concentrations of parathyroid hormone (PTH) are a constant feature of hypomagnesaemic hypocalcaemia (HMHC), while target organ resistance to PHT in kidneys and bone may be demonstrated in the majority of these patients. The failure of membrane-bound adenylate cyclase in the parathyroids, kidneys and bone, thought to be the most important molecular mechanism in HMHC, cannot explain the concomitant resistance to vitamin D and its metabolites. In recent years, information has accumulated on further magnesium-dependent intracellular events and alternative pathways of transcellular signalling. This may eventually allow the identification of one or more further biochemical mechanisms leading to hypocalcaemia in severe magnesium deficiency.

Adenylyl Cyclases↗
PubMed1991

Development of a luminescence immunoassay for follitropin suitable for clinical routine.

We developed a luminescence immunoassay (LIA) for follitropin, based on the synthesis of a follitropin-N-(4-aminobutyl)-N-ethylisoluminol conjugate. The luminescence tracer was purified by gel chromatography. Antibody-bound and non-bound tracer fractions were separated by using a second antibody reagent bound to magnetic particles. The assay can be performed within 24 hours and is sufficiently sensitive for the measurement of all clinically relevant follitropin concentrations including the subnormal range.

Analysis of Variance↗
PubMed1991

[Thyroid abcess. Apropos of 5 cases].

Thyroid abcess and acute suppurative thyroiditis are uncommon, representing 0.1 to 0.7% of surgically treated thyroid pathologies. More common in children than in adults, this rarity is associated with poorly indicative clinical symptoms, thus making diagnosis difficult. Five cases reports are presented, 4 of them in adults, illustrating the diagnostic difficulties and the various etiopathological mechanism, thereby explaining the wide diversity of pathogenic agents responsible. Treatment includes surgery (drainage or (partial) thyroidectomy, depending upon the presence or not of an underlying thyroid pathology) and intravenous antibiotics. It is absolutely necessary to eliminate the source of the infection, often a piriform sinus fistula whose total resection effectively prevents a relapse (1 case in this series).

Abscess↗
PubMed1990

[Hypomagnesemia-induced hypocalcemia: functional hypoparathyroidism, parathyroid hormone- and vitamin D-resistant].

In four patients with severe hypomagnesemia, hypocalcemia, and functional hypoparathyroidism (three patients with shortened bowel, one with alcoholism), sequential measurements of parameters of calcium metabolism were performed before and during intravenous administration of magnesium. Parathyroid hormone was immeasurably or inadequately low in all patients before magnesium injection, but rapidly rose to elevated values thereafter. Even without calcium supplements, serum calcium rose to normal levels within 2-5 days, although 1,25(OH)2-Vitamin D levels did not rise significantly. In the patient with alcoholism, hypophosphatemia developed during the first days after admission; the rise of serum calcium preceded the elevation of cyclic adenosine monophosphate in urine. A transient rise of urinary calcium was observed in two patients after initiation of magnesium therapy, with a subsequent fall to subnormal levels in spite of normal serum calcium concentrations. The findings were considered to be due to partial parathyroid hormone resistance during the phase of magnesium replenishment.

Adult↗
PubMed1990

Tumor-induced osteomalacia: pre- and postoperative biochemical findings.

A patient with late-onset hypophosphatemic osteomalacia was treated with oral supplements of phosphate (1.5 g/day) and calcitriol (1.5-3.0 micrograms/day) for 17 months, before a slowly growing tumor in the first metatarsal space became evident. Before treatment concentrations of inorganic phosphate (Pi) and calcitriol in serum and tubular reabsorption of phosphate (TRP) were very low, calcium and parathyroid hormone (PTH) in serum were normal, urinary cyclic adenosine monophosphate (cAMP) was strongly elevated. During the first weeks of conservative treatment urinary cAMP returned to normal; concomitantly there was a transient slight fall in PTH. Serum calcium was in the low normal range and did not significantly change during conservative therapy. During the further course PTH rose to pretreatment values, but urinary cAMP remained normal. When the dose of calcitriol was elevated to 3 x 1.0 micrograms/day, leading to slightly elevated serum concentrations of this substance, Pi in serum rose to the low normal range, but TRP remained low and bone pain, although improved, did not subside. The tumor was locally excised. Postoperatively calcitriol concentration became elevated within 48 hours and remained so for several weeks. The rise in calcitriol concentration preceded the elevation of Pi in serum, not, however, the increase of TRP. The elevation of urinary cyclic AMP before therapy may have been due to a direct action of the substance secreted by the tumor.

Adult↗
PubMed1989

Survey of falls of inpatients at the Ryde Hospital in 1986.

OBJECTIVE: To outline the findings of one survey, and to raise some general issues about falls. METHOD: A retrospective survey of all recorded inpatient falls in 1986. RESULTS: There were 74 falls recorded in 1986, which gave an incidence rate of 0.184 falls per hundred bed days. Due to the lack of data on falls from other local hospitals, no meaningful comparison can be made. Not unexpectedly, the elderly were at greatest risk of falling, and the most common type of fall was from bed. Most falls caused no major injuries.

Accidental Falls↗
PubMed1988

Experiences of the Ryde Hospital Day Only Unit in 1986 and 1987.

OBJECTIVE: To monitor and summarise activity of a Day Only Unit as a guide to management. METHOD: Attitude survey (patient questionnaire) of adults admitted to the Day Only Unit over a six week period, a telephone survey and an ongoing monthly record review of length of stay and complications. RESULTS: The level of "day only" activity is increasing and procedures affecting the quality of care of these patients are being improved. Patients not receiving pre-medications had fewer post-operative symptoms. The most frequent patient complaint related to the coldness of the ward.

Day Care, Medical↗
PubMed1987

Measurement of factor VIII procoagulant antigen in normal subjects and in hemophilia A patients by an immunoradiometric assay and by an enzyme-linked immunosorbent assay.

Factor VIII coagulant antigen (FVIII:Ag) and FVIII coagulant activity (FVIII:C) were measured in 102 healthy individuals, in 5 hemophilia A carriers and in 21 hemophilia A patients before and after infusion of heat-treated high-purity FVIII concentrates. Factor VIII:Ag was determined by a solid-phase micro enzyme-linked immunosorbent assay (ELISA) using monoclonal antibodies and by a conventional solid-phase immunoradiometric assay (IRMA). Factor VIII:C was assessed using a one-stage assay. The micro ELISA was decidedly more precise than the IRMA. There was a close correlation between the results obtained by the three assays in the plasma of healthy subjects and in hemophilia A carriers. After transfusion of FVIII concentrates to hemophilia A patients, the FVIII:Ag recoveries were significantly lower than the FVIII:C recoveries and the biological half-life of FVIII:Ag was significantly shorter than for FVIII:C. The calculated half-life of FVIII:C was longer than in any previous study.

Adolescent↗
PubMed1985

Experimental autoimmune myasthenia gravis: can pretreatment with 125I-labeled receptor prevent functional damage at the neuromuscular junction?

Rats were immunized with purified receptor from electric fish to induce experimental autoimmune myasthenia gravis (EAMG). It is implied by the clonal selection theory that antigens react only with receptors on specific immunocompetent cell subpopulations. In an attempt to damage these specific cells with the aid of highly radioactive antigen, one group of rats was pretreated with an additional injection of radiolabeled receptor of high specific activity 3 days before the basic immunization. The success of the immunization was monitored by measuring changes in the following three parameters: antibody titers against nicotinic acetylcholine receptor; number of alpha-bungarotoxin-binding sites at endplates; and number of acetylcholine-operated ionic endplate channels, using quantitative electrophysiologic methods. Conventionally immunized animals showed the classical signs of EAMG: elevated antibody titers against nicotinic acetylcholine receptor and a reduction of the number of alpha-bungarotoxin-binding sites, as well as reduction of the number of acetylcholine-operated ionic channels. The same symptoms were found in animals pretreated with unlabeled receptor and in animals pretreated with radioactive albumin. Animals pretreated with radioactively labeled receptor showed far less reduction of functional nicotinic acetylcholine receptor and only slightly raised antibody titers. This study suggests that preimmunization with radioactive antigen selectively eliminates immunocompetent cells, thus precluding the production of antibodies by a subsequent immunization procedure. The same protective effect cannot be obtained by either preimmunization with unlabeled antigen or by radioactively labeled unspecific antigen.

Animals↗
PubMed1984

Metabolic and hormonal responses to exhaustive supramaximal running with and without beta-adrenergic blockade.

The metabolic and hormonal responses to exhaustive short-term supramaximal exercise were studied in 10 male physical education students. The exercise task was a single bout of running on the treadmill at 22 km X h-1 and 7.5% slope. It was performed with single oral doses of 100 mg Bupranolol (non-selective beta-blockade), 100 mg Metoprolol (beta-1-selective blockade), and placebo. Arterialized capillary and venous blood were sampled until 30 min post exercise. Time to exhaustion was 52.0 +/- 2.6, 47.6 +/- 2.0, and 46.0 +/- 1.9 s in the control, Metroprolol, and Bupranolol experiments. At cessation of exercise, adrenaline and noradrenaline were grossly elevated in all three conditions. Lactate and glucose increased markedly, this being accompanied by increasing insulin in the control and Metoprolol, but not the Bupranolol trials. Glycerol increased moderately, while FFA were depressed. Growth hormone showed a delayed increase at 15 and 30 min post exercise. Cortisol was unaffected by exercise. beta-blockade reduced the increases of lactate, glucose, glycerol, insulin, and growth hormone, exaggerated the depression of FFA and had no effect on cortisol. The results demonstrate that the strong sympatho-adrenal response to exercise of this nature is a major determinant of the increase of glucose at cessation of exercise. The hyperglycemia in concert with beta-2-adrenergic stimulation leads to elevation of insulin. Furthermore, lipolysis is controlled by beta-adrenergic stimulation. The delayed increase of growth hormone seems to be triggered by the declining glucose level during recovery.

Adrenergic beta-Antagonists↗
PubMed1984

Effect of highly radiolabelled 2,4-dinitrochlorobenzene (DNCB) on experimental DNCB contact dermatitis in guinea pigs.

With the aid of epicutaneous application of 2,4-dinitrochlorobenzene (DNCB) solution in acetone, we induced a cutaneous allergic reaction of the delayed type. Our question was whether the development of the DNCB cutaneous sensitivity could be suppressed by highly radiolabelled DNCB. On the basis of the clonal selection theory and our own results with other in vivo-experimental animal models, one could suppose that the highly radiolabelled DNCB as haptens binds to the Ig-membrane receptors of the genetically determined T-lymphocyte clone, and that the conjugated radioactivity (125I) causes a selective radioactive damage to this competent T-lymphocyte subpopulation. By means of intracardially applied radiolabelled DNCB, we are able to induce either complete or very significant suppression of the cutaneous DNCB immune response. In the second experiment, the highly radiolabelled DNCB was not able to inhibit sensitization to a simultaneously applied 4-ethoxy-methylene-2-phenyl-oxazolone (oxazolone). This result clearly demonstrates the antigen specificity of this form of immune suppression.

Animals↗