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Biomedical subjects

N Ali

Publications and source records attributed to N Ali.

At least 19 recordsLinked to original sources
PubMed1992

Identification of G-proteins in rat parotid gland plasma membranes and granule membranes: presence of distinct components in granule membranes.

We have identified by immunoblotting and ADP-ribosylation by cholera toxin and pertussis toxin the presence of Mr 43 and 46 KDa Gs alpha, and 39 and 41 KDa Gi alpha subunits in rat parotid gland plasma membranes but not in granule membranes. A Mr 28 KDa polypeptide that served as substrate for ADP-ribosylation by both cholera toxin and pertussis toxin was present exclusively in granule membranes. Photoaffinity crosslinking of [alpha-32P]GTP showed the presence of high molecular weight GTP-binding proteins (Mr 160, 100 KDa) in granule membranes. Six low molecular weight GTP-binding proteins (Mr 21-28 KDa) were differentially distributed in both plasma membranes and granule membranes. The present study identifies various GTP-binding proteins in rat parotid gland plasma membranes and granule membranes, and demonstrates the presence of distinct molecular weight GTP-binding proteins in granule membranes. These granule-associated GTP-binding proteins may be involved in secretory processes.

Amylases↗
PubMed1992

Stimulation of bone collagen and non-collagenous protein synthesis by products of 5- and 12-lipoxygenase: determination by use of a simple quantitative assay.

The influence of 5- and 12-lipoxygenase products on the rate of collagen and non-collagenous protein (NCP) synthesis by murine calvarial explants has been investigated using a new assay based on the resistance of native collagen to degradation by pepsin. The reproducibility and simplicity of this assay allows the quantitative estimation of the rate of bone formation in large numbers of cultures. Hydroxyeicosatetraenoic acids (HETEs) stimulated both the rate of collagen and NCP synthesis with maximal stimulation occurring at 10-100 pM. All leukotrienes stimulated collagen synthesis. LTB4, C4 and D4 showed similar dose-responses with maximal activity occurring at 100 pM. LTE4 was less potent only showing activity at 1-10 nM. Only LTD4 demonstrated the capacity to stimulate NCP synthesis with significant stimulation being seen at 10 nM. The extreme sensitivity of bone collagen and NCP synthesis to lipoxygenase products suggests that these mediators may play a physiological role in bone remodelling.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed1992

Liver microsomes contain multiple forms of inositol 1,4,5-trisphosphate binding proteins: identification by nitrocellulose blot overlay.

A group of proteins binding to inositol 1,4,5-trisphosphate (IP3) has been identified in rat liver microsomes by a nitrocellulose blot-overlay technique. Proteins were resolved by SDS-PAGE, blotted on nitrocellulose and incubated with [32P]IP3 followed by autoradiography. Approximately eight IP3-binding polypeptides ranging M(r) 23-50 kDA were present exclusively in microsomes; these were absent from plasma membrane and mitochondrial fractions. Binding of [32P]IP3 to these proteins was displaceable to a great extent by 5 microM unlabeled IP3 but not by 10 microM IP1, IP2, IP4, ATP, or GTP gamma S. These results suggest that liver microsomes contain multiple forms of IP3-binding proteins that can be detected by this new method.

Animals↗
PubMed1992

A literature review of dermatotoxicity.

Dermatotoxicity is the skin's response to chemical substances that produce damage. Penetration of the chemical to the various skin layers is important and may result in irritation, allergic contact dermatitis, contact urticaria, one of various forms of photosensitization, or other cutaneous reactions. The testing of new products or industrial chemicals for potential dermatotoxicity is an important process in protecting the public's health.

Absorption↗
PubMed1991

Functional dissection of Drosophila abdominal-B protein.

The Abdominal-B gene is unique among homeotic Drosophila genes as it encodes two proteins m and r which confer different functions. The m protein corresponds to an r protein with a large N-terminal extension; the two proteins contain the same homeodomain. We have used a transient co-transfection assay, based on HeLa cells, to analyse the intrinsic function of m and r protein in activating transcription. We find two strong transcriptional activation domains in the common part of the two proteins. The m-specific exon contains additional transcriptional activation potential. Despite this, the m protein is a weaker transcriptional activator than the r protein. Apparently, there are inhibitory sequences in the m-specific exon which, in the embryo, may have a role in masking r function in the intact m protein.

Animals↗
PubMed1991

Membrane damaging potential of photosensitized riboflavin.

Riboflavin upon exposure to UV and visible radiations has been shown to produce active oxygen species. The present work deals with erythrocyte membrane as model system to study the damaging potential of photosensitized riboflavin. Membrane preparations (2.5 mg protein/ml) following exposure to sunlight in presence of riboflavin for different time intervals revealed significant inhibition of ATPases, p-nitrophenyl phosphatase and acetylcholinesterase. Considerable increase in lipid peroxidation was caused by the photosensitized riboflavin. Quenching studies using specific scavengers indicated remarkable inhibition. The production and identification of reactive oxygen species by photosensitized riboflavin and their possible involvement in membrane damaging effect has been discussed.

Erythrocyte Membrane↗
PubMed1990

Distribution of polypeptides binding guanosine 5'-[gamma-[35S]thio]triphosphate and anti-(ras protein) antibodies in liver subcellular fractions. Evidence for endosome-specific components.

The subcellular distribution in rat liver of polypeptides binding guanosine 5'-[gamma-[35S]thio]triphosphate [( 35S]GTP[S]) and seven antibodies against ras oncoproteins was evaluated. Multiple low-Mr (21,000-28,000) GTP-binding proteins were detected, but their relative distribution among the membrane fractions varied. A more specific compartmentation of polypeptides which bind antibodies generated against ras proteins was evident, with an Mr-28,000 polypeptide and a probable Mr-56,000 dimer, identified by six of the antibodies tested, being confined mainly to endosomes. An Mr-23,000 polypeptide was detected by some of the antibodies in all of the membrane fractions, but especially in the plasma membranes.

Animals↗
PubMed1979

Systolic honk in heart failure: its origin and mechanism of production.

Systolic honks have so far been synonymous with prolapse of the mitral valve leaflet. Evidence of tricuspid valve involvement in two cases is presented. These patients developed systolic honk during the deterioration of their congestive heart failure. Simultaneous recordings of echocardiograms and phonocardiograms showed fluttering of the tricuspid valve, coinciding with the systolic honk. This fluttering was not seen when honk was absent. The mechanism of production of this honk is discussed.

Adult↗
PubMed1979

Right-sided infective endocarditis: an echocardiographic study.

Echocardiographic observations are described in 10 patients with right-sided bacterial endocarditis. Six of the nine patients with tricuspid regurgitation had shaggy echoes on the tricuspid valve, which were confirmed to be vegetations on autopsy in two patients. In six patients, right ventricular dilatation was present, and paradoxic septal motion was seen in four. In one of the patients with pulmonic valve endocarditis, the pulmonic valve and right ventricular outflow tract revealed the shaggy echoes in diastole, along with systolic fluttering of the pulmonic valve, right ventricular dilatation and paradoxic septal motion. When the findings are supplemented to the clinical picture, echocardiography is found to be a useful noninvasive adjunct in the diagnosis of acute vegetative bacterial endocarditis involving the right side of the heart, especially if other clinical features, e.g., fever, leukocytosis and positive blood cultures are absent.

Adult↗
PubMed1978

'Spontaneous' platelet aggregation: its characteristics and relation to aggregation by other agents.

Platelet aggregation results of 117 patients were analysed. All had documented evidence of stroke, recurrent transient ischemic attacks and other neurologic symptoms, and all were hospitalized in the same Rehabilitation Center. Attention was specifically directed to the 'spontaneous' platelet aggregation (SPA) phenomenon, in terms of its characteristics and relationship to platelet count and aggregation induced by 3 physiologic agents. About 50% of the samples showed SPA but not all of them were hyperaggregable by other aggregating agents. A great deal of variation was found in the aggregation time, slope and extent of SPA. These variations do not always appear to relate to platelet count, or the responsiveness of platelets to other aggregating agents.

Adult↗
PubMed1977

Echocardiographic observations in opiate addicts with active infective endocarditis. Frequency of involvement of the various values and comparison of echocardiographic features of right- and left-sided cardiac valve endocarditis.

Echocardiographic observations are described in 25 opiate addicts with active infective endocarditis involving apparently previously normal valves. Infective endocarditis was isolated to the tricuspid valve in 11 patients, involved both right- (tricuspid valve) and left-sided valves in 7 and was isolated to the left-sided valves in 7 (mitral valve in 6). Twenty patients (80%) had tricuspid valve regurgitation, 12 had mitral regurgitation, 3 had aortic regurgitation and none had pulmonary valve regurgitation. Considering the 75 cardiac valves (excluding the pulmonary) in the 25 patients, echocardiographic abnormalities consistent with active infective endocarditis were detected in 26 (74%) of the 35 clinically incompetent valves but in none of the 40 competent valves. Comparison of the 20 incompetent tricuspid valves with the 12 incompetent mitral valves indicated that (1) the echocardiogram was less sensitive in detecting tricuspid valve lesions, (2) rupture of tricuspid valve chordae tendineae was absent or not detectable, and (3) tricuspid valve vegetations tended to be larger.

Adult↗
PubMed1977

Cardiovascular effects of dobutamine in severe congestive heart failure.

The effects of continuous infusion of dobutamine 5 to 15 microgram/Kg./min. were studied in 17 patients using right heart catheterizations, echocardiography, and/or the Systolic Time Intervals. HR increase was dose-related, but insignificant (p less than 0.05) rate increase was obtained at infusion rates below 15 microgram/Kg.)min. C.O. increased from 2.9 +/- 0.7 to 5.0 +/- 1.2 liters/min. (p less than 0.001), and the stroke volume from 30 +/- 6 to 49 +/- 14 ml./min. (p less than 0.005). The mean BP did not change, P.A.W.P. decreased from 30 +/- 7 to 20 +/- 8 mm. Hg (p less than 0.001) and R.A.P. from 20.0 to 12.0 mm. Hg (p less than 0.005). The P.E.P.I. decreased from 160.93 +/- 54.91 to 133.4 +/- 28.7 msec. (p less than 0.050). Echo-determined mean VCf increased from 0.387 +/- 0.14 to 0.537 +/- 0.13 cm. (p less than 0.010), diastolic diameter did not change significantly, but the end systolic diameter decreased from 6.020 +/- 0.69 to 5.750 +/- 0.70 cm. (p less than 0.025). During a mean infusion period of 75 hours, the only side effects noted were transient nausea and/or vomiting at 15 microgram/Kg./min. dose range in two patients, and multifocal P.V.C.'s following 68 hours of infusion in another patient. It is concluded that in the dose range of 5 to 15 microgram/Kg./min., dobutamine is well tolerated and is a very potent inotropic agent with only minor effects on the heart rate and blood pressure.

Adult↗
PubMed1977

Echocardiographic diagnosis of supravalvular aortic stenosis.

The echocardiographic features of supravalvular aortic stenosis seen in a patient with valvular aortic and multiple pulmonary branch stenosis are described. Since patterns of valvular, discrete subvalvular, and supravalvular aortic stenosis can be recognized by echocardiography, it is now possible to screen close relatives of patients having supravalvular aortic stenosis and pulmonary branch stenosis by this non-invasive technic.

Adolescent↗