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J Abraham

Publications and source records attributed to J Abraham.

198 records · Page 11Linked to original sources
PubMedDate not supplied

Immunoreactive arginine-vasopressin in Brattleboro rat ovary.

Homozygous (di/di) Brattleboro rats have normal hypothalamic levels of oxytocin and neurophysin I, but undetectable levels of neurophysin II and arginine-vasopressin (AVP). This defect has been presumed to be at the genomic or transcriptional level, as AVP messenger is reported to be drastically reduced, if not absent, from the hypothalamus of Brattleboro rats. Recent studies suggest de novo production of various neuropeptides in the mammalian gonad, including AVP. We report here the detection and localization of immunoreactive (ir) AVP in the luteal cells of adult homozygous Brattleboro rats, and the modulation of this ovarian ir-AVP by gonadotropins. These findings are thus consistent with a tissue-specific defect of AVP expression in the magnocellular neurones of the Brattleboro rat, and suggest that a comparable defect does not occur in the ovaries of such animals.

Animals↗
PubMedDate not supplied

Disordered cholinergic neurotransmission and dysautoregulation after acute cerebral infarction.

The possible role of displaced neurotransmitter acetylcholine (ACHh) in dysautoregulation was examined after experimental regional cerebral infarction was produced by occluding the middle cerebral artery (MCA) in babons. Regional cerebral blood flow (rCBF) was measured after intracarotid injection of 133Xenon using the gamma camera. Autoregulation was tested with metaraminol or angiotensin infusion and the autoregulation index (A.I.) was calculated. Acetylcholinesterase (ACHhE) was measured in brain tissue of noninfarcted and infarcted hemispheres. Cerebral arteriovenous (A-V) differences for cholinesterase (ChE) were also measured. Regional dysautoregulation was found in infarcted gray matter and correlated with increased AChE levels in the same zones of cortex and basal ganglia. The time course of onset of dysautoregulation correlated with increased ChE uptake by the brain. Intravenous infusion of the cholinergic neurotransmitter blocker, scopolamine, restored autoregulation to the ischemic zones. Autoregulation appears to be a myogenic reflex, influenced by neurogenic and metabolic mechanisms.

Acetylcholinesterase↗
PubMedDate not supplied

Regional cerebral blood flow measured by the gamma camera after direct injection of 133Xe into the distal stump of the occluded middle cerebral artery.

Regional cerebral blood flow (rCBF) was measured after intracarotid injection of 133Xe concurrently with measurements of local cerebral blood flow (LCBF) after injection of 133Xe directly into the distal stump of the occluded middle cerebral artery (MCA) by the use of the gamma camera after producing experimental ischemia in baboons by occluding the MCA. Regional MCA stump pressure (rMCAP) was also measured. Regions of ischemia assessed by intracarotid injection of 133Xe correlated well with the territory of infarct defined by injection of 133Xe into the distal MCA stump. Flow values in ischemic regions obtained by direct injection of 133Xe into the MCA were 15% to 20% lower than those obtained by intracarotid injection of 133Xe. Possible explanations for these differences are discussed. During induced hypertension autoregulation in ischemic areas was abolished and paradoxical responses of LCBF and rMCAP to changes in arterial carbon dioxide tension (PaCO2) were confirmed.

Animals↗
PubMedDate not supplied

Assessing periodontal pathogens in children with varying levels of oral hygiene.

This study investigated the presence of organisms Actinobacillus actinomycetecomitans (A.a.), Bacteroides intermedius (B.i.), and Bacteroides gingivalis (B.g.), believed to be associated with periodontal disease etiology in children. The study included fifty children, aged six to fourteen years, selected from patients seeking routine dental care at Children's Hospital National Medical Center. A Modified Plaque Index (MPI) denoting the clinical presence and severity of the periodontal disease was obtained for each patient and ranged from 0-3. A total of 200 samples were obtained from the gingival crevice of the mesial surface of all first permanent molars and tested with DNA probes for the presence of three microorganisms. No correlations were found between race, sex, age, and the Modified Plaque Index. The results show that A. actinomycetecomitans was found only in patients with MPI greater than or equal to 1. B. gingivalis was present only in combination with another organism.

Actinobacillus↗
PubMedDate not supplied

Muscular dystrophy.

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Adolescent↗