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J Gyarmati

Publications and source records attributed to J Gyarmati.

At least 19 recordsLinked to original sources
PubMed2000

Dual regulation of leptin secretion: intracellular energy and calcium dependence of regulated pathway.

Rodent leptin is secreted by adipocytes and acutely regulates appetite and chronically regulates body weight. Mechanisms for leptin secretion in cultured adipocytes were investigated. Acutely, energy-producing substrates stimulated leptin secretion about twofold. Biologically inert carbohydrates failed to stimulate leptin secretion, and depletion of intracellular energy inhibited leptin release. There appears to be a correlation between intracellular ATP concentration and the rate of leptin secretion. Insulin increased leptin secretion by an additional 25%. Acute leptin secretion is calcium dependent. When incubated in the absence of calcium or in the presence of intracellular calcium chelators, glucose plus insulin failed to stimulate leptin secretion. In contrast, basal leptin secretion is secreted spontaneously and is calcium independent. Adipocytes from fatter animals secrete more leptin, even in the absence of calcium, compared with cells from thinner animals. Acute stimulus-secretion coupling mechanisms were then investigated. The potassium channel activator diazoxide and the nonspecific calcium channel blockers nickel and cadmium inhibited acute leptin secretion. These studies demonstrate that intracellular energy production is important for acute leptin secretion and that potassium and calcium flux may play roles in coupling intracellular energy production to leptin secretion.

Adenosine Triphosphate↗
PubMed1999

Fetal type lymphocytes in insulin dependent diabetes mellitus.

CD5+ B and gamma/delta T lymphocytes constituting a major population in the fetus and newborn infant, represent two small subsets of the B and T lymphocyte compartment in healthy adults. There is evidence for their potential involvement and relative expansion in autoimmune disorders. In insulin-dependent diabetes mellitus (IDDM) CD5+ B lymphocyte counts have been found to be increased or normal. The aim of our study was to determine the percentage of both "fetal type" lymphocyte subsets in peripheral blood of 22 recently diagnosed children with IDDM, in that of 13 high risk subjects (islet cell antibody (ICA) positive non-diabetic Ist degree relatives of diabetic children) and in 43 healthy controls. The percentage of gamma/delta TCR+ cells and of CD5+ B lymphocytes was found to be significantly (p < 0.0001 and p = 0.03, respectively) higher in the diabetic and prediabetic groups as compared to controls. Young children with IDDM associated antibodies carry a higher risk of developing clinical IDDM than older individuals. In our hands, the percentage of both CD5+ B and gamma/delta T lymphocytes was higher in the younger population. However, age-dependent decrease for both lymphocyte subpopulations in IDDM-prediabetic patients was less than in healthy controls. Since the above subpopulations are supposed to play a role in immune response to conserved structures, these observations would suggest a higher capacity of older individuals to 'natural autoimmunity" and would explain at least in part the increased risk of antibody positive young children to develop IDDM.

Adolescent↗
PubMed1988

[Sonography of experimental hypovascularized kidney tumors].

The authors studied the sonographic features of Vx2-renal carcinomas in rabbits induced by the Vargha method. The series consisted of 81 rabbits with Vx2-renal carcinomas, 17 controls, five rabbits with retrorenal Vx2-carcinomas and 56 rabbits with gluteal Vx2-carcinomas. In 70.8% ultrasound showed changes on the tenth day and in 98.6% on the 14th day; usually these were of low echogenicity, in 32.4% there was mixed echogenicity and in a few a highly echogenic pattern was found. After 21 days the ultrasound pattern became increasingly of poor echogenicity. 41.3% showed of necrosis by 14 days and after 21 days 100% were necrotic. On the seventh day Vx2-renal carcinomas were mostly hyper-reflective.

Animals↗
PubMed1988

The effect of ipriflavone treatment on osteoporosis induced by immobilization.

The purpose of these experiments was to study the effect of Ipriflavone (7 isopropoxy-isoflavone) on the osteoporosis induced by immobilization. The immobilization was produced by plaster cast of the right hind limb in young and old rats. Ipriflavone was administered via a gastric tube in a daily dose of 40 mg/kg body weight for 8 weeks. On the basis of histological and histomorphometric examinations of the tibia, results of Ipriflavone treatment are the following: 1) The decrease in the density and volume of spongy trabecules was less apparent in both meta- and diaphysis; 2) The amount of persisting cartilage core and structural rarefication of trabecules were diminished; 3) In the metaphysis osteoblastic activity was considerably enhanced; 4) Bone resorption and cortical thinning were decreased; 5) Bone remodeling was increased subperiosteally and to small extent also endosteally; 6) The treatment did not prevent the development of osteoporosis but significantly diminished it.

Aging↗
PubMed1987

Morphological studies on the articular cartilage of old rats.

Age-dependent morphological alterations of the tibial articular cartilage were studied in 26-month-old Wistar rats of both sexes. Young and adult rats (6 and 10 months of age, respectively) served as a basis for comparison. Light microscopic histology, polarization optical analysis (toluidine-blue staining with or without the addition of 0.2, 0.4 or 0.8 M MgCl2, as well as after phenol reaction) as well as transmission electron microscopy were applied. The main observations are: (1) According to the histological findings, the proportion of the zones changes with age; the subchondral bone layer becomes wider and separated to a certain extent, while the fibres become demasked. (2) Polarization microscopy revealed a disorientation of both the proteoglycane (PG) and collagen molecules; considering the available biochemical data, this phenomenon involves both quantitative and structural changes, as well as differences in the localization of the PG and collagen molecules. (3) Electron microscopy also supports the structural alterations of the collagen (thin and thick, as well as non-striated, fragmented fibres). Cellular alterations are also observed parallel with the changes of the matrix (cell organelles occur less frequently, signs of degeneration and disintegration, rupture of the plasma membrane, as well as accumulation of lipid-bodies can be seen. On the basis of the findings, one can consider the articular cartilage in the old rats as a tissue which is still in equilibrium, however, aged chondrocytes with decreased function become predominant in it. This state can be modified into a pathological one by various mechanical, endocrinological, iatrogenic, post-traumatic, etc., influences through the alterations of the cell-matrix interactions.

Aging↗
PubMed1987

Radiological investigation of alterations in the rat femur after long-term immobilization.

The right hind limb of female rats was immobilized by plaster cast. Following 8 weeks of immobilization the alterations were compared with either the contralateral extremity of the same rat or with the extremities of non-immobilized animals. The femurs were investigated by microradioscopic, morphometric, densitometric and atom absorption methods. The results obtained have unequivocally shown that long-term immobilization by plaster cast leads to development of osteoporosis in the rat. Even though no considerable loss of calcium could be demonstrated when calculated in terms of unit layer thickness quantitative analysis of the bone revealed a high degree of osteopenia.

Animals↗
PubMed1986

Arthropathy in haemodialysed patients.

The joint disorders associated with osteodystrophy of 124 regularly haemodialysed patients are reviewed. The most common signs and symptoms of uraemic osteoarthropathy are summed up. It is pointed out that in osteoarthropathy accompanying chronic renal failure or haemodialysis the bones are generally affected first, arthropathy being secondary to this process. In addition to the classic signs and symptoms of arthropathy (calcification, pain, stiffness) capsulitis, carpal tunnel syndrome and in 3 cases avascular necrosis were observed. The laboratory findings included hypocalcaemia, hyperphosphataemia and hypersecretion of parathormone. The current preventive and therapeutic measures are reviewed and in this context the benefits of combined local lidocaine, and steroid iontophoresis are emphasized in the light of personal observations.

Calcinosis↗
PubMed1986

Effect of plaster-cast immobilization on the bone.

Plaster-cast of the right hind limb resulted in immobilization osteoporosis in rats. The alteration was characterized by loss of the bony substance as well as by a partial transformation of lamellar bone to primordial osseous tissue. In the basis of histological and histomorphometric findings, an accelerated osteoclastic activity, an increased osteocytic osteolysis and a decreased ossification are responsible for the observed changes.

Animals↗
PubMed1984

Experimental calcipenic osteopathy.

Calcipenic osteopathy was used as a model, in order to reveal the diagnostic value and capacity of the noninvasive radiological methods (microradioscopy, densitometry, and Roentgen-morphometry), in comparison with the results of histological, histomorphometrical, and atomic absorption methods. The study proved that calcipenic diet causes an osteoporosis in the experimental animals. The alterations observed meet both the histological and radiological criteria.

Animals↗
PubMed1983

Alterations of the connective tissue in nude mice.

The epiphyseal cartilage of nude mice was studied by light and electron microscopy. The resting and maturation zones become narrow and mineralization of the ground substance starts already in the zone of proliferation. Electron microscopy reveals signs of degeneration in the chondrocytes of this latter zone. An increased osteoclast activity can be observed in the metaphysis. The alterations may be due to a decrease in T-cell-mediated immunoreactivity of nude mice, as well as to an increased production of the osteoclast-activating factor, which might be attributed, among other things, to the B lymphocytes or macrophages.

Animals↗
PubMed1981

The effect of experimental hypothyrosis on the fine structure of the epiphyseal cartilage of young rats.

Authors studied the effect of hypothyrosis induced by thyro-parathyroidectomy and mercaptoimidazole treatment on the fine structure of the proximal epiphyseal cartilage of tibia in growing male rats. It has been established that the cell density of the epiphyseal cartilage decreases in the experimental hypothyrosis, about 30 to 50% of the chondrocytes display degenerative signs, whereas the Golgisystem seems to be well developed. The most characteristic alteration appear in the zones of proliferation and maturation of the epiphyseal cartilage. The endoplasmic reticulum (ER) and mitochondria show a considerable regression also in the chondrocytes displaying minimal or even no signs of degeneration. Elements indicating calcification were encountered more frequently in the cartilaginous matrix of the zones of maturation and calcification under the effect of mercaptoimidazole treatment as compared to the controls, whereas the matrix of the animals operated was poorer in minerals than the corresponding zones of the controls. This difference is attributed by the authors to the different levels of thyrocalcitonin in the two kinds of experiments.

Animals↗
PubMed1980

Goodpasture's syndrome: haemodialysis, pacing and extrapulmonary oxygenation.

Two cases of Goodpasture's syndrome are reported. Intensive therapy, extracorporeal oxygenation by haemodialysis, assisted respiration and short-term pacing were applied together with immunosuppressive treatment and repeated exchange transfusions. By this treatment combined with bilateral nephrectomy a few weeks' remission was attained in a young female patient. An intensive therapy of this kind is recommended in rapid progressive glomerulonephritis of other types as well.

Adult↗