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Biomedical subjects

S Hussain

Publications and source records attributed to S Hussain.

At least 19 recordsLinked to original sources
PubMed1992

Cysteine protects Na,K-ATPase and isolated human lymphocytes from silver toxicity.

Metal-binding proteins are important components of retroviruses such as human immunodeficiency virus (HIV). Therefore, metals could be used as antiviral agents. However, most metals are toxic for humans with the exception of silver which is toxic only to prokaryotic cells and viruses. In addition, HIV infection causes a decrease in body cysteine. We formed a complex of silver and cysteine, named silver-cysteine. Healthy human lymphocytes were incubated with silver-nitrate or silver-cysteine. Negligible cell survival was seen at 50 microM silver-nitrate. However, in presence of 1 mM cysteine, the viability remained unaffected up to 1 mM of silver. Further, silver inhibition of isolated Na,K-ATPase was easily reversed by cysteine. Thus, non-toxic silver-cysteine could be used as an anti-viral and cysteine-replenishing agent.

Animals↗
PubMed1992

A peptidergic component to vagally induced tracheal vasodilation in the dog.

The purpose of the study was to determine the extent that peptidergic afferent and efferent pathways contribute to vagally induced vasodilation in the trachea of the dog. The change in vascular resistance of the tracheal branch of the cranial thyroid artery and the trachealis responses were determined in 28 anesthetized, paralyzed, and mechanically ventilated dogs. After propranolol (2 mg/kg) and phentolamine (1.5 mg/kg), stimulation of the superior laryngeal nerves (NS; 15 Hz, 7 V, 2 ms, 30 s) caused a decrease in vascular resistance of 11.7 +/- 0.8% and a tracheal contraction of 5.2 +/- 4.7 cmH2O. Atropine (1.5 mg/kg) reduced the fall in vascular resistance to 4.7 +/- 0.8% (P less than 0.01), whereas tracheal contraction was abolished. Thiorphan (1.5 mg), a neutral endopeptidase inhibitor, augmented the decrease in vascular resistance (8.8 +/- 0.6%; P less than 0.01) to NS. After hexamethonium (0.5 mg/kg), NS still caused a small decrease in TVR (2.9 +/- 0.9%; P less than 0.05), which was abolished by capsaicin. In atropinized dogs, capsaicin reduced the fall in vascular resistance after NS; the residual vasodilation was virtually abolished by hexamethonium. Acetylcholine (10(-3) mg/kg) decreased vascular resistance (15.7 +/- 3.0%), and the effect was abolished by atropine. We conclude that there is noncholinergic nonadrenergic vagally induced tracheal vasodilation that is peptidergic. The peptidergic vasodilation appears to be mediated by both afferent and efferent pathways.

Acetylcholine↗
PubMed1992

Increased lipid peroxidation in patients on maintenance hemodialysis.

Lipid peroxidation products, lipid hydroperoxide and malonaldehyde were measured in the serum of patients on maintenance hemodialysis and compared with values obtained from a group of healthy controls. Dialysis patients had significantly elevated levels of lipid peroxidation products (12.9 +/- 1.9 vs. 9.3 +/- 1.3 nmol/ml, mean +/- SD, patients vs. controls, p less than 0.0001). In contrast, the serum transferrin level was significantly lower in the dialysis patients (217 +/- 71 vs. 290 +/- 50 mg/dl, patients vs. controls, p less than 0.0002). Compared to normal controls HDL cholesterol was lower (40 +/- 11 vs. 53 +/- 8, p less than 0.0001) and triglycerides were higher (206 +/- 103 vs. 142 +/- 64, p less than 0.007) in the patient group. The patient group was then divided on the basis of using polysulfone or cupraphane dialyzers. Patients using polysulfone dialyzers had lower levels of 2-thiobarbituric acid-reactive substances (12.3 +/- 0.9 vs. 13.6 +/- 2.1, polysulfone vs. cupraphane, p = 0.05), and higher transferrin concentrations (248 +/- 84 vs. 194 +/- 37, p = 0.03). Thus, in patients on maintenance hemodialysis there was evidence for accelerated lipid peroxidation. This abnormality was more marked in patients using traditional cupraphane dialyzers. The mechanism for this observation remains unclear.

Adult↗
PubMed1992

Alpha thalassaemia in Saudis.

The alpha-thalassaemias are group of inherited anaemias. Their severity is known to increase with the number of alpha-globin genes deleted. Employing different types of restriction enzymes, we found that alpha-thalassaemia-2 are more common than held previously. On the basis of our results we also anticipate that the haplotype alpha alpha alpha anti3.7/ occurs at a higher frequency.

Blotting, Southern↗
PubMed1992

The role of extracellular medium components and specific amino acids in the cytotoxic response of Escherichia coli and Chinese hamster ovary cells to hydrogen peroxide.

A concentration of H2O2 resulting in mode one killing of Escherichia coli is more toxic when exposure to the oxidant is performed in complete medium (K medium), as compared to a saline (M9 salts). Inorganic salts (MgSO4 and CaCl2), thiamine or glucose, when added separately, or combined, to M9 salts had no effect on the cytotoxic response to H2O2. In contrast, the lethality of the oxidant was highly dependent on the presence of the amino acids in the incubation medium. The addition of glucose further enhanced this response. Among the seventeen amino acids which are present in the complete amino acid mixture, only two, i.e. L-histidine and L-cystine, were found to increase the toxicity of H2O2. Again, glucose augmented this response. The effect of these amino acids on the growth inhibitory action of hydrogen peroxide was also tested in Chinese Hamster Ovary cells. It was found that L-histidine was capable of increasing the toxicity of the oxidant whereas all the other amino acids did not affect the toxicity of the oxidant. Glucose only slightly augmented this effect of L-histidine. DNA single strand breakage produced by H2O2 was increased by L-histidine and was not significantly modified by the other amino acids. DNA double strand breakage was also shown to occur in cells exposed to H2O2-L-histidine, and this effect was independent on the presence of glucose. These results demonstrate that the cytotoxic response of bacterial and mammalian cells to challenge with H2O2 is highly dependent on the composition of the extracellular milieu.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1992

Total hip arthroplasty for protrusio acetabuli: a 3- to 9-year follow up of the Heywood technique.

Thirty-five total joint arthroplasties (34 patients) were performed in patients who had protrusio acetabuli. Twenty-nine percent of the patients had acetabular protrusio of grade I, while 71% had grade II and grade III protrusio. The mean follow up was 4 years (range: 3 to 9). Cemented acetabular components were used in 11 hips; 24 hips received an uncemented porous coated acetabular component. The patient evaluations included preoperative and postoperative Harris Hip Ratings and standard radiographs. In all cases, the medial wall defect was reconstructed with the solid autogenous femoral head as described by Heywood. The mean preoperative Harris Hip Rating was 45 (range: 30 to 60 points), and the postoperative mean was 85 (range: 70 to 100 points). Radiographically, the preoperative protrusio measured a mean of 8.8 mm (range: 6 to 18 mm), and the mean postoperative placement of the femoral head was 10 mm lateral to Kohler's line (range: 6 to 13 mm). There were no acetabular component failures and no acetabular bone graft resorptions. All autogenous grafts were incorporated to the host radiographically by 1 year post-surgery. This study corroborates previous work which suggests that medial-placed bone grafting is not resorbed and consolidates with the host bone. We find this technique extremely useful in dealing with this technical problem.

Acetabulum↗
PubMed1991

Evaluation of the roll over test as predictor of gestational hypertension in African women.

Fifty-six primigravid women at 28-32 weeks gestation were studied prospectively to assess the roll over test (ROT) as a predictor of gestational hypertension in African women. Blood pressures were measured continuously in the supine and left lateral positions using an automated accutor machine. ROT was positive in only two women (3.6%). These two women later developed gestational hypertension but so did 18 others who had negative ROT. Measures that may be useful in increasing the predictive value of the ROT in these women are suggested.

Blood Pressure Determination↗
PubMed1991

Receptor sub-types involved in responses of Purkinje cell to exogenous excitatory amino acids and local electrical stimulation in cerebellar slices in the rat.

The effects of the NMDA receptor antagonist, 2-amino-5-phosphonovalerate (APV) and non-NMDA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) on responses of Purkinje cells to exogenous excitatory amino acids and to electrical stimulation of the parallel fibres, were investigated in slices of the cerebellum of the rat. Glutamate, aspartate, kainate and quisqualate all induced excitation of Purkinje cells. Responses to kainate and quisqualate were blocked by CNQX (10 microM) but not by APV (10 microM). N-Methyl-D-aspartate induced biphasic excitatory-inhibitory responses, both components of which were blocked by APV but not by CNQX. The inhibitory component was less sensitive to blockade by APV but was totally blocked by bicuculline, the GABAA receptor antagonist. Parallel fibre stimulation most commonly induced inhibition of Purkinje cells, with or without preceding excitation. This inhibition was blocked by APV and excitatory responses were often revealed. A less commonly-observed predominantly excitatory response was blocked by CNQX but not by APV and inhibition tended to be revealed. These data suggest that parallel fibre-Purkinje cell synapses possess non-NMDA postsynaptic receptors, while the parallel fibre-inhibitory interneuron synapses possess functional NMDA receptors.

2-Amino-5-phosphonovalerate↗
PubMed1991

Modulation of GABA-mediated inhibition in rat cerebellar slices by benzodiazepine receptor ligands.

1. Extracellular recordings were made from the Purkinje cell layer of rat cerebellar slices. Compounds were perfused over the slice and bipolar stimulating electrodes placed in the external layer of the slice close to the recording electrode. 2. Stimulus-evoked inhibition of Purkinje layer cell activity was sensitive to bicuculline methiodide and picrotoxin, suggesting it was gamma-aminobutyric acid (GABA) mediated. The benzodiazepine ligands RU 32007 and Ro 19-0528 reversibly increased the period of inhibition, as did pentobarbital. This benzodiazepine effect was antagonised by Ro 15-1788. 3. Five inverse agonists all reduced the period of stimulated inhibition and this effect was reversed by Ro 15-1788, suggesting the involvement of benzodiazepine receptors. 4. It is concluded that this system provides a convenient physiological and possibly quantitative model for studying the action of benzodiazepine receptor ligands.

Animals↗
PubMed1991

Technical report: wire guided sialography.

An improved technique for performing sialography in difficult cases is described. This is based on the passage of a cannula into the salivary duct ostium over a thin, flexible, blunt guide-wire.

Catheterization↗
PubMed1991

Failure of oxygen radical scavengers to modify fatigue in electrically stimulated muscle.

We used in situ gastrocnemius muscle of anaesthetized dogs to test the hypothesis that O2 radical production during muscle contraction contributes to fatigue. Muscle tension was measured with a force transducer and blood flow was monitored with an electromagnetic flow probe. Muscle contractions were produced by stimulating the nerve for 15 min at 20 Hz, 12 trains/min, and a duty cycle of 0.25. Three groups of seven animals were given an infusion of 0.2 mL.min-1 of either saline, low-dose oxygen radical scavengers (250 IU.mL-1 superoxide dismutase, 640 IU.mL-1 polyethylene glycol (PEG)-catalase, 0.25 mg.mL-1 deferoxamine, and 0.1 mg.mL-1 oxypurinol), or high-dose oxygen radical scavengers (3300 IU.mL-1 superoxide dismutase, 6600 IU.mL-1 PEG-catalase, 2.5 mg.mL-1 deferoxamine, and 0.1 mg.mL-1 oxypurinol). Blood flow and vascular resistance of the gastrocnemius muscle during stimulation did not differ among groups. After 15 min of stimulation, the developed tension (represented as a percentage of initial tension developed) was 66 +/- 7% in the saline treated group, 70 +/- 6% in the low-dose group, and 70 +/- 4% in the high-dose group. The change in tension during recovery was not significant in the control or low-dose groups. However, there was partial recovery in the high-dose group. In conclusion, in this preparation, oxygen radical scavengers did not delay the development of decreased muscle tension.

Animals↗
PubMed1978

Arterial thrombosis in essential thrombocythemia.

The course of essential thrombocythemia has been observed in ten patients, ages 46 to 83, of whom nine were followed for a period of 4 months to 9 years. In contrast to the experience with essential thrombocythemia recorded in the literature, manifestations of arterial thrombosis were far more common than hemorrhage. In six of the ten patients, the presenting complaints were ascribable to incipient gangrene of the toes and several of these patients additionally developed occlusion of tibial and larger arteries while under our observation. All patients with incipient gangrene showed marked clinical improvement accompanying busulfan-induced reduction and normalization of the platelet count. Relapses in five patients after 2 to 87 months responded well to retreatment with busulfan. No patient has shown evolution to another myeloproliferative disorder. Essential thrombocythemia should be considered in the differential diagnosis of occlusive arterial disease.

Aged↗
PubMed1978

Histalog gastric analysis.

A histalog gastric analysis was done in 20 patients with gastroduodenal disorders and 12 subjects with non-ulcer dyspepsia who were used as controls. Due to overlap of secretory responses its use as a diagnostic tool is limited. About 46% patients with duodenal ulcer exceeded the upper limit of acid secretion of control subjects. Values for stimulated secretion in controls and the patients with gastric ulcer were the same. Endoscopy if possible is the investigation of choice for the diagnosis of gastroduodenal disorders and the secretory studies should be limited to patients under-going surgery for peptic ulceration.

Adult↗
PubMed1977

The radiology of nasal injuries: problems of interpretation and clinical relevance.

Films of 50 normal patients and 50 dry skulls were examined to detect lines which might stimulate a nasal fracture. These were visible on the occipito-mental view but on the lateral view any line which reaches the anterior cortex must be regarded as a fracture. The results of an analysis of 100 patients with trauma to the nasal bone are also presented. It is concluded that radiography of the nasal bone is an unnecessary examination unless requested by the E.N.T. surgeon, and this will in any case occur infrequently.

Fractures, Bone↗