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Biomedical subjects

M Tabatabai

Publications and source records attributed to M Tabatabai.

34 records · Page 2Linked to original sources
PubMed1976

Effect of electrical stimulation of the medullary respiratory neurons on respiratory air flow in cats. New findings on expiratory neurons.

Respiratory air flow during electrical stimulation of the medullary respiratory neurons was measured in 25 sodium pentobarbital-anesthetized cats. The effect of variation of stimulus parameters on the air flow was studied too. The medullary respiratory neurons were localized by exploring the medulla with microelectrodes. The inspiratory neurons were found hetween 2 and 4 mm lateral to the midline, and from the level of the obex to 4 mm rostrally in the ventral reticular formation. The expiratory cells were between 2 and 3 mm lateral to the midline, extending from the level of the obex to 3 mm caudally, slightly less ventral than the inspiratory neurons. The maximal inspiratory and expiratory flow rates were 56 and 44 liters per minute respectively when the respiratory neurons were stimulated with a stimulus of 4 volts and 200 Hz/sec., while duration of the stimulating pulse was 0.5 millisecond. In general, the increase in air flow was proportional to the magnitude of the stimulus strength, stimulus frequency and duration of the stimulating pulse.

Animals↗
PubMed1975

Ureterometrographic studies on human subjects with normal urinary tract system.

Ureteral motility was studied in 40 subjects with normal urinary tract systems. Although the contraction waves were often monophasic in shape some were characterised by the presence of a notch on the contraction or relaxation limb of the peristaltic complex, indicating that notched complexes do not necessarily signify obstructive uropathy. Retrograde filling of the bladder to within its physiologic limits with isotonic saline solution markedly changed the pattern of the ureteral activity.

Adolescent↗
PubMed1975

Localization of the medullary respiratory neurons in rats by microelectrode recording.

Neuronal activity has been recorded extracellularly from the medulla of anesthetized rats. Units whose discharge frequency varied in phase with respiratory airflow were located bilaterally between 1.5 and 2 mm lateral to midline, extending from 1 mm caudal to 1.5 mm rostral to the obex, in the ventral two-thirds of the medulla. Expiratory units predominated and were intermingled with inspiratory units. Ten different patterns of discharge were distinguished, varying from a short burst at the beginning of expiration to a resting discharge which increased in frequency during either inspiration or expiration. Evidence was also obtained that fiber tracts from other areas of the brain cross midline just caudally to the obex and pass to the respiratory centers on which they apparently exert and excitatory action.

Animals↗
PubMedDate not supplied

Effect of ovine hydatid cyst fluid on the cardiovascular and respiratory systems in sheep.

Rupture of the hydatid cyst in man brings about mild to severe toxic reactions including death. The present study was undertaken to investigate some of the responses resulting from administration of the ovine hydatid fluid to the sheep, which, like man, is an intermediate host of the Echinococcus granulosus. In 50 sodium pentobarbital-anesthetized sheep, the arterial blood pressure (A.B.P.), central venous pressure (C.V.P.), respiration and electrocardiogram were recorded. Intraveonus administration of 5-10 ml hydatid fluid brought about moderate to severe fall in A.B.P. and rapid respiration with or without transient apnea or permanent repiratory cessation in 80 percent of the animals. Fifty percent of the sheep died of circulatory and respiratory failure after the first injection of the hydatid fluid. Boiled hydatid fluid did not lose its potency to evoke the above responses. Pretreatment of the aminals with atropine sulfate, 0,5 mg/kg subcutaneously, did not block the reactions. Administration of the antihistamine chlorpheniramine, 4 mg/kg intravenously, caused partial prevention of the reactions in 6 out of 10 responsive sheep. The cardiovascular and respiratory responses to ovine hydatid fluid may be due to antigen-antibody reactions or some toxic component of the fluid.

Animals↗
PubMedDate not supplied

Effects of saline extract of ovine hydatid cyst scoleces in sheep. Blockade of responses by compound 48/80.

The effects of intravenous administration of the saline extract of the ovine hydatid cyst scoleces on the cardiovascular and respiratory systems were studied in sodium pentobarbital-anesthesized sheep. Scoleces were obtained from the lung hydatid cysts of freshly slaughtered sheep, sonicated in physiologic saline and centrifuged to recover the extract in the supernatant fluid. Administration of 1-4 ml of the saline extract resulted in hypotension, shallow rapid respiration, slight elevation of the central venous pressure and transient electrocardiographic changes. Pretreatment of the animals with atropine, 1 mg/kg S.C., or with the antihistamine antazoline, 5 mg/kg I.V., did not block the responses to the saline extract of hydatid cyst scoleces. Pretreatment with compound 48/80, a histamine releaser, abolished the reactions to the administration of the scoleces extract. It is concluded that ovine hydatid scoleces extract has profound cardiovascular and respiratory effects, and that histamine release seems to be involved in the induction of responses to the extract.

Animals↗