PubMed Health⌕ Search

Biomedical subjects

J Mantz

Publications and source records attributed to J Mantz.

81 records · Page 5Linked to original sources
PubMed1989

Early bronchopulmonary lesions in rat lung after normobaric 100% oxygen exposure and their evolution. A light and electron microscopic study.

In order to clarify the early phenomena involved in the lung reaction to hyperoxia, twenty adult male rats were exposed to 100% oxygen at 1 ATA. Morphological pulmonary lesions were detectable after only 24 h hyperoxia, and included vasoconstriction and perivascular oedema, bronchiolar constriction, and pericyte reaction. The lesions were irregularly scattered within the lung parenchyma and occurred preferentially in areas centred on bronchiolo-vascular stems. Even at the latest stages, pulmonary heterogeneity was obvious, from the coexistence of areas damaged at different times. Neuro-epithelial-bodies were found under the bronchiolar epithelium; the morphological aspect of the neuro-endocrine cells observed was consistent with hyperoxia-induced modulation of their secretory activity. Taken together, our findings show the speed of development of hyperoxia-induced pulmonary changes and raise some pathogenic considerations.

Animals↗
PubMed1989

[Echocardiographic detection of adriamycin cardiotoxicity. Study of the relationship between the shortening fraction-constraint and the systolic shortening fraction-diameter of the left ventricle].

Cardiotoxicity is the main obstacle to the use of high-dosage adriamycin in chemotherapy. It is difficult to decide whether or not treatment should be continued when the cardiac function -- irrespective of the method by which it is evaluated -- is at the lower limit of normality. Some authors consider that chemotherapy can be pursued as long as the shortening fraction of the echocardiographic diameter remains within normal limits in relation to the end-systolic constraint. We have established the limits of normality of this relationship before chemotherapy in 53 patients with normal cardiovascular system. We conclude that the end-systolic constraint essentially depends on the end-systolic diameter, so that the results provided by the study of the shortening fraction end-systolic constraint relationship are qualitatively the same as those of the shortening fraction-end-systolic diameter relationship, which is much easier to obtain. It seems to us that the criteria of cardiotoxicity after administration of adriamycin 300 mg/m2 are: (1) shortening fraction lower than 25 p. 100; (2) ventricular dilatation (end-systolic diameter greater than 40 mm) without associated valve disease; (3) reduction of the shortening fraction (whatever its value) in relation to the end-systolic diameter by more than 2 standard deviations on the regression slope of the correlation; (4) more than 25 p. 100 reduction of the shortening fraction after administration of adriamycin 300 mg/m2, betraying a high sensitivity to the cardiotoxic effects of the drug. Such individual sensitivity, studied in 25 patients, seemed to vary widely from one subject to another and to be independent of the initial status.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Differential effects of ascending neurons containing dopamine and noradrenaline in the control of spontaneous activity and of evoked responses in the rat prefrontal cortex.

The medial prefrontal cortex receives converging projections from the mediodorsal thalamic nucleus, dopaminergic cells from the ventral tegmental area dn noradrenergic cells from the locus coeruleus. Stimulation of the ventral tegmental area inhibits the spontaneous activity of prefrontal cortical neurons and blocks the excitatory response evoked by stimulation of the mediodorsal thalamic nucleus (10 Hz). The aim of the present study was to compare the influence of dopaminergic and noradrenergic afferents on the spontaneous and evoked activity of medial prefrontal cortical neurons. In ketamine-anaesthetized rats, repetitive stimulation (20 Hz, 10 s) of the locus coeruleus produced a long-lasting post-stimulus inhibition (mean duration: 45 s) of the spontaneous activity of 56% of the tested cells. This effect was decreased markedly following selective destruction of the ascending noradrenergic pathways (local 6-hydroxy-dopamine injection) or depletion of cortical catecholamines by alpha-methyl-para-tyrosine pretreatment, suggesting that these inhibitory responses are mediated by noradrenergic neurons. The excitatory response to mediodorsal thalamus nucleus stimulation (10 Hz) could still be evoked during the post-stimulus inhibitory period induced by locus coeruleus stimulation (20 Hz, 10 s) resulting in the enhancement of signal-to-noise ratio. On the other hand, a population of prefrontal cortex neurons (26%) was found to be reproducibly activated by noxious tail pinch. This evoked response was still present during the post-stimulus inhibitory period induced by locus coeruleus stimulation but was completely suppressed during stimulation of the ventral tegmental area (10 Hz). In conclusion, these results indicate that the dopaminergic and noradrenergic systems exert a completely distinct control of information transfer in the medial prefrontal cortex.

Animals↗
PubMed1987

[Syndrome of vagal hypertonia in a newborn infant manifested during the surgical repair of aortic coarctation associated with banding of the pulmonary artery].

We report a case of vagal hypertonia syndrome in a newborn infant, developed after surgical repair of an aortic coarctation combined with banding of the pulmonary artery trunk. The parasympathetic activity had adverse repercussions on haemodynamics. The diagnosis was confirmed by prolonged asystole on the oculocardiac reflex and by concomitant arrhythmia and disorders of conduction demonstrated by Holter recordings. To our knowledge, no other case of vagal hypertonia associated with a congenital cardiopathy has yet been reported. Infants with this syndrome are at a high risk of sudden death. Treatment with vagolytic drugs is of questionable value, and prolonged supervision of the patient is mandatory.

Bradycardia↗
PubMed1987

Effects of a low dose of pancuronium on oxygen consumption during sustained muscular exercise.

The effects of a low dose of pancuronium on muscular performance were studied in six healthy volunteers. Three dynamic exercise tests at increasing levels of power were performed by each subject on two consecutive days using an ergometric bicycle. To assess muscular function, oxygen consumption was measured in a steady state at each level of power output. Pancuronium 6-8 micrograms kg-1 or placebo was administered i.v. in a double-blind fashion before the second test each day. Plasma pancuronium levels were measured 8 min after administration but even with pancuronium clearly detectable in the plasma no significant differences were found either in oxygen consumption or in the haemodynamic measurements made. The authors conclude that such doses of non-depolarizing neuromuscular blocking agents do not disturb oxygen consumption during dynamic muscular exercise and are therefore unlikely to have a significant effect on muscular function.

Adult↗