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Biomedical subjects

A Nagy

Publications and source records attributed to A Nagy.

At least 271 records · Page 15Linked to original sources
PubMed1987

Quiescence and increased adhesion after mammalian DNA transfection of human fibrosarcoma cells.

When a population of human fibrosarcoma HT1080 cells was transfected with a mammalian expression vector and DNA pieces representing either the human whole genome or mouse bulk cDNA, there was a transient increase in the number of adhesive cells in the population. The number of cells with increased adhesion was proportional to the amount of transfected DNA; the increase occurred at a maximal frequency of between 10(-4) and 10(-5) per cell. Increased adhesion in these cells persisted for 9-12 days, corresponding to the period of highly efficient transient transfection, and was accompanied by arrest in cell division. Transfection of non-mammalian DNAs, reduction of transfected mammalian sequence length by restriction enzyme digestion, or omission of expression vector DNA did not permit these shifts in phenotype. The effects seen suggest that expression of specific transfected mammalian DNA sequences suppresses certain phenotypic characteristics in these transformed mammalian cells.

Cell Adhesion↗
PubMed1987

Neurotoxic effect of capsaicin in mammals.

Capsaicin is now widely used to explore and/or prove the role of peptide-containing primary afferent neurones in different somato- and viscerosensory functions. The present paper deals with the morphological effects of capsaicin administered according to currently used experimental paradigms. As it has been repeatedly confirmed in the recent literature, administration of capsaicin to newborn mammals results in a highly selective degeneration of a particular population of small sized, B-type primary afferent neurones located in spinal and cranial sensory ganglia. Chemosensitive i.e. capsaicin sensitive primary sensory neurones (CPSNs) correspond to primary sensory ganglion cells which contain neuropeptides. The permanent functional impairments and the decrease in the peptide contents of the sensory neurones observed after neonatal capsaicin treatment may be accounted for an irreversible loss of CPSNs. Direct application of capsaicin to peripheral nerves results in an apparently irreversible functional impairment of unmyelinated afferent fibres implicated in nociceptive, viscerosensory and neurogenic inflammatory mechanisms. Morphological observations indicate that perineural treatment with capsaicin initiates a selective but delayed degeneration process of unmyelinated afferent nerve fibres presumably due to an inhibition of intraneuronal transport mechanisms. In contrast with perineural capsaicin treatment affecting the chemistry and function of the whole sensory neurone, injection of capsaicin into the subarachnoid space results in an irreversible abolition of the "afferent" but not the "efferent" function of CPSNs. Accordingly, noxious thermal or chemical stimuli applied to the peripheral innervation areas of the trigeminal nucleus caudalis or the affected segments of the spinal cord fail to induce nociceptive reflexes because of the degeneration of the central terminals of CPSNs. However, in these same skin areas, application of chemical irritants invariably evoked the neurogenic inflammatory response, indicating that CPSNs deprived of their central terminals maintain their capacity to synthesize and release the peptide(s) responsible for the initiation of that response. In contrast with previous findings, our recent studies furnished evidence for a selective neurodegenerative action of systemically injected capsaicin in adult mammals, as well. Therefore, some of the irreversible functional impairments produced by capsaicin in adult animals may result from the degeneration of a particular subpopulation of CPSNs.(ABSTRACT TRUNCATED AT 400 WORDS)

Afferent Pathways↗
PubMed1987

Prenatal fate of parthenogenetic cells in mouse aggregation chimaeras.

Parthenogenetically activated BCF1 and fertilized BALB/c embryos were aggregated to form chimaeras. The fate of the parthenogenetic component was followed in the conceptus during the second half of gestation. The results indicate an early strong selection against parthenogenetic cells in the extra-embryonal part, which is presumably complete by term, and a weaker selective process in the embryo. During early development, parthenogenetic cells have nearly normal developmental potency in the embryo, which allows their balanced contribution in the chimaeras on day 12. Later, this contribution declines significantly resulting in an unbalanced relation to the advantage of the fertilized counterpart. From the results, we suggest that gametic imprinting may play a role not only in the key steps of preimplantation and early postimplantation development, but later in cell and tissue differentiation.

Age Factors↗
PubMed1986

The effect of adrenalectomy on the proteinuria of spontaneously hypertensive rats and normotensive controls.

Urinary proteins were studied by quantitative and electrophoretic methods in 6-month-old spontaneously hypertensive rats and normotensive controls. Protein analysis was carried out before and after adrenalectomy and during gluco- or mineralocorticoid treatment. Urinary protein excretion was significantly diminished after adrenalectomy both in the hypertensive and control groups. The original level of protein excretion was restored only by glycocorticoid treatment. Normal or pathologic electrophoretic pattern of urinary proteins was not influenced by the experimental procedure. Moderately non-selective glomerular proteinuria persisted in the spontaneously hypertensive rats referring to a definitely damaged glomerular barrier. One protein fraction of about 130,000 dalton molecular weight disappeared from the urine of hypertensive animals after adrenalectomy and reappeared after glucocorticoid treatment only. This fraction probably represents the dimeric form of albumin. Quantitative changes of urinary protein excretion can be explained by haemodynamic factors.

Adrenal Cortex Hormones↗
PubMed1986

Comparison of the postoperative changes in the humoral and cellular immune activity in septic and non-septic colorectal cancer patients.

The effect of sepsis on the host resistance of 34 colorectal cancer patients with normal preoperative immune reactivity was studied. A significant change (p less than 0.01) was found in the IgG level of the septic patients (n = 13) when comparing their values with those of the non-septic patients (n = 21), on the third and 7th days postoperatively. There was no appreciable change in the IgA and IgM levels. The E rosette formation and the blast transformation values of the patients showed a marked decrease on the 7th day postoperatively. In the non-septic patients the normal initial values reappeared on the 10th postoperative day, while in the septic cases they significantly decreased as compared to both their own values and to those of the non-septic patients assessed during the same period (p less than 0.05). The possible factors serving for the prevention of decrease in the resistance of the host organism, are discussed.

Colonic Neoplasms↗
PubMed1986

Histamine level changes in the plasma and tissues in hemorrhagic shock.

Histamine (H) levels have been reported during various types of shock, but there is a paucity of such data during hemorrhagic shock. The present study demonstrates a rapid, severalfold increase of radioenzymatically measured plasma H in conscious and anesthetized dogs subjected to experimental hemorrhagic shock. Shock was elicited by bleeding to a mean arterial blood pressure of 5.3 kPa, and maintained until 20% of the maximal bleeding volume (MBV) was taken back by the animal. The corresponding figures in the anesthetized group were 4 kPa and 30% uptake. The increased H level persisted in both groups during hypovolemia and remained above the control value following reinfusion. Survival was examined in the conscious group. At MBV, survivors had significantly higher H levels and H/norepinephrine and H/renin activity ratios in the plasma than nonsurvivors. The H level increased in the liver, lungs, spleen, left atrium and ventricle, and blood vessel walls (superior mesenteric artery, small jejunal arteries and veins, femoral artery and vein). The H/norepinephrine ratio increased in the left ventricle and blood vessel walls. The increase of H in the blood plasma and blood vessels during hemorrhagic shock may exemplify a counterregulation against excessive vasoconstriction and could be a positive factor in survival.

Animals↗
PubMed1985

Selective degeneration by capsaicin of a subpopulation of primary sensory neurons in the adult rat.

The morphological effects of systemic capsaicin treatment have been studied in adult rats. Light and electron microscopy revealed that a subpopulation of small-to-medium sized B-type primary sensory neurons, representing about 17% of the total neuronal population in the 4th lumbar spinal ganglion, underwent rapid degeneration after the administration of capsaicin. Quantitative electron microscopy demonstrated a decrease of about 45% in the number of unmyelinated axons in the saphenous nerve. Light microscopy showed extensive axon terminal degeneration in the brainstem and spinal cord confined to the central projection areas of capsaicin-sensitive afferent fibers, as has already been revealed in the newborn rat. The present results furnish evidence for a hitherto unrecognized selective neurodegenerative action of capsaicin in the adult rat.

Animals↗
PubMed1985

[Bartter syndrome].

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Bartter Syndrome↗
PubMed1985

A microcomputer method for recording and analysing behavioural elements.

The trend in ethology, psychopharmacology and behaviour genetics is to get increasingly higher resolution of the behaviour of animals, since it increases the sensitivity of the tests used. Consequently the higher resolution requires an increased data-logging efficiency, and a decreased time-investment for data handling. In this paper a method for inexpensive microcomputers is presented, which enables an individual experimenter to obtain frequency, relative duration and its variance from as many behavioural elements as desired.

Animals↗
PubMed1985

The effect of anaesthesia on the haemodynamic and sympathoadrenal responses of the dog in experimental haemorrhagic shock.

Studies were carried out to demonstrate the effect of sodium pentobarbital and morphine-pentobarbital anaesthesia on the haemodynamic and sympathoadrenal responses of dogs in haemorrhagic shock. The results were compared to those of conscious dogs and of dogs receiving only morphine. The reactivity of the cardiovascular system to exogenous adrenaline was also studied in every group. Pentobarbital did not change the resting plasma level of catecholamines but reduced the increase of plasma catecholamines in shock. In the pentobarbital-anaesthetized dogs in which shock was less severe, the reactivity of blood vessels to adrenaline was higher than in conscious dogs. In the haemodynamic response to shock the increase of heart rate predominated in the conscious dogs while the rise of blood pressure was more pronounced in the pentobarbital-anaesthetized animals. Subcutaneously injected morphine decreased the heart rate and increased the plasma catecholamine and histamine levels. Morphine-pentobarbital anaesthesia decreased the resting arterial pressure and increased the plasma histamine level while the plasma catecholamines were near their initial levels. Morphine alone increased the plasma catecholamines, and the subsequent shock could not induce as high a sympathoadrenal response as in the conscious dogs. Pentobarbital administered following morphine decreased the plasma level of catecholamines nearly to the conscious level but could not inhibit the sympathoadrenal activation induced by shock. Anaesthesia is a significant additional factor in the evaluation of shock experiments carried out on anaesthetized animals.

Adrenal Glands↗
PubMed1985

Changes in the tendency of lymphocytes to undergo blastic transformation in the postoperative period, in immune-stimulated and untreated colonic tumour patients.

A study was made of the blastic transformation of lymphocytes in the postoperative period in colonic tumour patients: 23 who had been immune-stimulated by vaccination, and 28 who had not been vaccinated. The immune reactivity decreased significantly in the majority of the cases; however, the deterioration of the immune status affected 68% of the nonvaccinated group, but only 48% of the vaccinated group. The data indicate that the vaccination primarily averted the deterioration of the defence ability in the early postoperative period in patients with a normal preoperative immune activity. An evaluable change in the immune reactivity did not occur in the 6-10 preoperative days following vaccination. Three months postoperatively, the number of patients giving a normal immune reaction was three-fold in the vaccinated than in the non-vaccinated group.

Colonic Neoplasms↗