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Biomedical subjects

M Globus

Publications and source records attributed to M Globus.

At least 37 records · Page 2Linked to original sources
PubMed1985

Amphetamine, but not reserpine, protects mice against dopaminergic neurotoxicity of MPTP.

In mice, long-term reductions in striatal DA produced by the neurotoxin MPTP were completely prevented by its combined administration with amphetamine. Depletion of DA from DA terminals by cotreatment with reserpine did not suppress but rather enhanced MPTP-induced DA decrements in striatum. Amphetamine protection against DA neurotoxicity of MPTP in mice is probably not due to increases in DA release and may be related to inhibition of MPTP transport into nigrostriatal terminals via the DA reuptake system.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1985

Pneumatocele formation in a patient with Proteus mirabilis pneumonia.

A rare case of pulmonary pneumatoceles complicating the course of Proteus pneumonia in an adult is described. The pneumatoceles which appeared early in the course of the pneumonia resolved completely without complications. A brief review of the literature regarding formation of cavities in Proteus pneumonia is given.

Female↗
PubMed1985

Cerebral blood flow and cognitive impairment in Parkinson's disease.

In Parkinson's disease, there is high prevalence of dementia, reduction of the regional cerebral blood flow (rCBF), and neuronal loss and Alzheimer-like pathologic changes in cerebral cortex. Since rCBF is also decreased in Alzheimer's dementia, it is theoretically possible that both decreases in rCBF and cognitive impairment in parkinsonians are caused by a similar mechanism, eg, reduced metabolic demand or loss of cholinergic neurons innervating cortex and microvessels. We therefore measured rCBF using the 133Xenon inhalation technique and evaluated cognitive function with a detailed neuropsychological test battery in 48 patients with Parkinson's disease. Mean brain, hemispheric, and regional flows were decreased in parkinsonians as compared with those in age-matched controls. Most of the cognitive functions were impaired in patients as compared with those in normal subjects. However, there was no correlation between the magnitude of rCBF reduction and the presence and severity of intellectual deterioration in parkinsonians, suggesting that each may be caused by a different mechanism.

Adult↗
PubMed1985

Progressive age-related decrease in regional cerebral blood flow in healthy subjects.

Regional cerebral blood flow (rCBF) was measured by the 133xenon inhalation technique in 103 healthy, nonhospitalized subjects of whom 44 were less than 30 years of age. Mean brain and hemispheric flows and rCBF decreased with advancing age. Moreover, a steep decline in rCBF became apparent as early as the third decade of life. Our findings suggest that the decline of rCBF is not limited to healthy elderly subjects, but is a progressive phenomenon that begins at an earlier age.

Adolescent↗
PubMed1984

In vitro effects of insulin on macromolecular events in newt limb regeneration blastemata.

This work provides data demonstrating a stimulatory effect of insulin on macromolecular events occurring in cultured regeneration blastemata and demonstrates a synergistic interdependence between nerves and insulin in newt limb regeneration. The current experiments provide evidence for the following: (1) Insulin is paramount for expression of the mitogenic effect of nerves on cultures blastemata. (2) Insulin stimulates the incorporation of (3H)uridine into the acid-insoluble fraction of blastemal homogenates, but it does not alter the turnover rate of incorporated labeled uridine. (3) Insulin also stimulates the incorporation of 35SO4 and (3H)leucine into both chondroitinase-sensitive and chondroitinase-resistant blastemal proteoglycans. (4) Insulin increases the uptake of radiolabeled precursors by the blastemata, namely, (3H)leucine, (3H)uridine, 35SO4, (3H)alpha-aminoisobutyrate, and (3H)2-deoxy-D-glucose. The importance of insulin in the regulation of newt limb regeneration is discussed.

Animals↗
PubMed1984

beta-Endorphins (beta-EP) in amphibians: higher beta-EP levels during regenerating stages of anuran life cycle and immunocytochemical localization of beta-EP in regeneration blastemata.

Plasma beta-endorphin (beta-EP) levels were measured at different stages of metamorphosis in anuran species, namely Rana catesbeiana, R. pipiens, and Xenopus laevis. The mean levels of beta-EP in tadpoles and postmetamorphic juveniles were significantly higher than adult levels in all three species examined. The pattern of high tadpole levels and low adult levels corresponds with the limb regeneration ability of the tadpole and restriction in the adult. We have also reported plasma beta-EP levels in two urodele species, Ambystoma tigrinum and A. jeffersonianum. Localization of beta-EP by immunocytochemistry shows bright fluorescence to beta-EP antiserum in the wound epithelium of the regeneration blastema. The mesoderm and nuclei of all blastema cells remain nonreactive. It is suggested that receptors to beta-EP reside in the epidermis.

Ambystoma↗
PubMed1984

Chromosomal aberrations induced by sodium nitrite in bone marrow of adult rats and liver cells of transplacentally exposed embryos.

A commonly used food preservative, sodium nitrite, was administered in the drinking water to pregnant (d 5-18 of gestation) and nonpregnant albino rats. Sodium nitrite induced chromosomal aberrations in bone marrow of both pregnant and nonpregnant adults and liver of transplacently exposed embryos. The magnitude of the effect was greater in embryonic liver cells than in adult bone marrow cells.

Animals↗
PubMed1984

Dysphagia as a primary manifestation of hyperthyroidism.

A 69-year old woman suffered from severe dysphagia, abdominal pain, and weight loss. The dysphagia was accompanied by nasal speech, nasal regurgitation of food, weakness, and wasting of the proximal muscles of the upper and lower girdles. Laboratory data revealed T3 sephadex uptake 65.2%; T4 15.1 mcg%; and T3 250 ng%. Treatment with antithyroid medication reversed the manifestation of all the symptoms, including dysphagia. Cine-studies revealed esophageal motor dysfunction as the cause of the dysphagia. Hyperthyroidism is a rare, but treatable cause of unexplained dysphagia.

Aged↗
PubMed1984

Effect of treatment and withdrawal from chronic lithium in rats on stimulant-induced responses.

Chronic lithium (Li) administration to rats was found to inhibit the hyperactivity induced by 0.5 mg/kg d-amphetamine but not that induced by 1.0 mg/kg d-amphetamine. Contradictory results on the ability of Li to inhibit amphetamine-induced hyperactivity may be due to the different dosages of amphetamine employed. 2 days after withdrawal from 3 weeks of chronic Li administration, rats showed no rebound supersensitivity of the hyperactivity response to 0.5 mg/kg d-amphetamine. Surprisingly, Li-withdrawn rats showed a marked subsensitivity of the stereotypy response to apomorphine. Such subsensitivity to apomorphine in Li withdrawal may relate to recent reports of homovanillic acid increases in rat brain in Li withdrawal, and to clinical reports of Li withdrawal inducing psychosis.

Animals↗
PubMed1984

Suppression of L-dopa-induced circling in rats with nigral lesions by blockade of central dopa-decarboxylase: implications for mechanism of action of L-dopa in parkinsonism.

Dopamine (DA) elevations in rat striatum produced by combined administration of L-dopa and carbidopa were abolished when L-dopa was injected with NSD-1015, an inhibitor of central dopa-decarboxylase. In all rats with unilateral 6-OH-DA nigral lesions, L-dopa-induced contraversive circling occurred after carbidopa, but was totally abolished (in 60%) or markedly suppressed after pretreatment with NSD-1015. Administration of the DA metabolites DOPAC and HVA systemically and of 3-methoxytyramine intrastriatally evoked no circling in animals with 6-OH-DA lesions. In rats with unilateral nigrotomies, the direction of L-dopa-induced circling was reversed and became ipsiversive after DA receptors were reduced by the addition of kainic acid lesions in ipsilateral striata. Findings provide evidence that circling in rats--and by analogy, efficacy in parkinsonians--requires the decarboxylation of exogenous L-dopa and interaction of the formed DA with DA receptors in striatum.

Animals↗
PubMed1983

Differential effect of acute and chronic haloperidol administration on dopamine turnover in rat nigrostriatal and retinal dopaminergic neurons.

Haloperidol-induced increases in DOPAC and HVA declined in the striatum but remained unchanged in the retina after chronic pretreatment with haloperidol (1-4 weeks). DA concentrations were unaffected in the striatum but decreased in the retina after acute or chronic haloperidol administration. Light stimulation increased both retinal DA and DOPAC. The findings indicate that acute and chronic haloperidol affect nigrostriatal and retinal DA neurons differentially. In addition, DA neurons in retina respond differently to activations by haloperidol and light.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1983

A comparison of beta-endorphin levels in regenerating and nonregenerating vertebrates.

The mean plasma level of beta-endorphin in the newt, Notophthalmus viridescens, as measured by radioimmunoassay, is significantly higher than the circulating levels of beta-endorphin in the anuran, Rana pipiens, and in mammals (humans and mice). The newt beta-endorphin level is found to be 6-fold greater than mammalian levels and three times greater than the levels observed in Rana pipiens. The high levels are maintained in the newt throughout limb regeneration.

Animals↗
PubMed1983

Combined administration of direct dopamine receptor agonists and L-dopa does not interfere with utilization of exogenous L-dopa in rat corpus striatum.

The effect of combined administration of L-dopa with apomorphine or with bromocriptine on rat striatal concentrations of dopamine (DA), dihydroxyphenylacetic (DOPAC) and dopa was investigated. Injections of apomorphine or bromocriptine alone decreased striatal DOPAC levels indicating suppression of DA turnover in nigrostriatal terminals. The dopa-induced elevations in striatal concentrations of DA, DOPAC and dopa were similar among animals injected with L-dopa alone or in combination with apomorphine or bromocriptine. These findings suggest that although direct DA receptor agonists decrease striatal DA turnover, they do not interfere with utilization of exogenous L-dopa in striatum.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1983

Effect of exercise on cerebral circulation.

The effect of supine physical exercise on cerebral blood flow (CBF) was measured in 30 normal subjects with the 133Xe inhalation technique. The CBF measurements were correlated to changes in PCO2, heart rate, and blood pressure, and to cardiac output and right atrial pressure in 10 of the subjects who underwent Swan-Ganz catheterization. No significant change was found in CBF during physical exercise, although a marked increase in cardiac output, blood pressure, and right atrial pressure and a mild decrease in PCO2 were found. Cerebrovascular resistance increased by 38%, in contrast to a decrease of 33% in the peripheral vascular resistance. The factors that affect the mechanism of cerebrovascular autoregulation during exercise are discussed.

Adult↗
PubMed1983

Effect of decortication on striatal dopamine turnover.

In rat striatum, frontal decortication did not affect the basal and the haloperidol-induced increases in dopamine (DA) turnover and the elevation in DA and dihydroxyphenylacetic acid concentrations produced by systemic administration of L-Dopa. These findings fail to support a role for the corticostriatal afferents in modulation of dopamine synthesis and release by nigrostriatal neurons. They suggest that DA receptors presumably localized on presynaptic corticostriatal terminals do not mediate the acceleration of DA turnover induced by neuroleptics. Data also indicate that corticostriatal terminals do not represent a locus for decarboxylation of exogenous L-Dopa to DA in the striatum.

3,4-Dihydroxyphenylacetic Acid↗