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Biomedical subjects

A Hasan

Publications and source records attributed to A Hasan.

At least 91 records · Page 5Linked to original sources
PubMed1994

Heat shock protein peptides reactive in patients with Behçet's disease are uveitogenic in Lewis rats.

Mycobacterial and homologous human heat shock protein T cell peptide epitopes specific for T lymphocytes in Behçet's disease were investigated for their pathogenicity in Lewis rats. The potential pathogenicity of eight peptides and two controls was assessed by administering the peptides in enriched Freund's adjuvant into the footpads of male Lewis rats. Anterior uveitis which is a major manifestation of Behçet's disease was induced with two out of the four mycobacterial and all four homologous human peptides. The most effective peptides inducing iridocyclitis in 64-75% of rats were peptides with amino acids 336-351 and 136-150, derived from the sequence of the human 60-kD heat shock protein. A few of the rats also showed evidence of focal loss of photoreceptors. These results suggest that selected peptides within heat shock protein 60 kD which function as T cell epitopes in Behçet's disease are capable of inducing uveitis in rats. This supports the view that the peptide T cell determinants may be involved in the pathogenesis of Behçet's disease.

Amino Acid Sequence↗
PubMed1994

Odor discrimination deficits in schizophrenia: association with eye movement dysfunction.

Odor discrimination deficits were found in 80% of 20 schizophrenia patients and in none of the 20 age- and sex-matched comparison subjects. Olfactory discrimination was reliably measured in the patients. Twelve patients in this study also had smooth pursuit eye movement (SPEM) qualitatively recorded. The olfactory discrimination scores were highly correlated to SPEM but not to other clinical measures. This correlation suggests a shared neurobiology, possibly involving working memory.

Adult↗
PubMed1994

Videothoracoscopy in the diagnosis of intrathoracic pathology: early experience.

We report our experience using the new technique of videothoracoscopy in the diagnosis of intrathoracic pathology. In the last 12 months, 40 patients (24 male; 16 female) have undergone investigation by this method. Lung biopsy has been performed in 17 patients, pleural biopsy in 20 patients and mediastinal biopsy in three patients. The majority had been referred after other investigations had been inconclusive. All biopsies were diagnostic except one mediastinal biopsy. This early experience suggests that videothoracoscopic biopsy is a well-tolerated technique with high diagnostic yield.

Adolescent↗
PubMed1993

T cell epitope expression of mycobacterial and homologous human 65-kilodalton heat shock protein peptides in short term cell lines from patients with Behçet's disease.

T cell epitopes of the 65-kDa heat shock protein (HSP) were mapped in patients with Behçet's disease (BD), by stimulating T cells with the overlapping synthetic peptides derived from the sequences of the Mycobacterium tuberculosis 65-kDa HSP. Significant lymphoproliferative responses were stimulated with four HSP peptides in BD, as compared with the related disease (recurrent oral ulcers), unrelated disease, and healthy controls (p < 0.05 to 0.005). In order to assess the relative frequency of sensitized lymphocytes by these peptides, 7353 short term cell lines were generated from the lymphocytes of patients and controls. Peptides 111-125, 154-172, and 311-325 (p < 0.001) and peptide 219-233 (p < 0.02) yielded significantly greater frequency of STCL in BD than in healthy and disease controls. All but peptide 154-172 stimulated only the CD4+ subset of T cells, although there was no evidence that reactivity to the selected peptides is restricted by DR2 to DR7 Ag. HLA-B51 is significantly associated with BD, but there was no evidence that B51 was a restricting element, when B51+ patients were compared with B51- patients with BD, and with B51+ healthy control subjects. A comparative investigation was then carried out between the corresponding mycobacterial and human HSP peptides. Similar or higher lympho-proliferative responses were stimulated by the human peptides compared with the mycobacterial peptides. These results suggest that the four peptide determinants within the 65-kDa HSP might be involved in the pathogenesis of BD. Whereas the high microbial load and associated stress proteins found in oral ulceration of BD may initiate an immune response to these conserved epitopes, expression of autoreactive T cell clones might be stimulated by immunodominant T cell epitopes of endogenous HSP which may induce immunopathologic changes.

Adult↗
PubMed1993

The reaction of bovine lens alpha A-crystallin with aspirin.

Acetylation of the lysines of bovine lens alpha A-crystallin has been examined after 0-48-hr incubations of whole alpha-crystallins in 100 mM aspirin. The alpha A-crystallins were isolated after the incubation, proteolytically digested into peptides which were separated by reversed phase HPLC and analysed by mass spectrometry. For the reaction conditions used in this investigation, acetylated lysyl residues were the principal products. The extent of acetylation was quantified from the intensities of the peaks in the fast atom bombardment mass spectra of the modified and unmodified peptides. The modified lysine containing peptides demonstrated that all seven lysyl residues of alpha A-crystallin reacted with aspirin; the extent of acetylation at each lysyl residue varied. Plots of the extent of acetylation vs. time were used to calculate rate constants for the reaction at each lysyl residue. The rate constant for the acetylation of Lys 166, the most reactive, was about seven times greater than for Lys 88, the least reactive. These rate constants were used to calculate the yield of predicted products for the reaction of alpha-crystallin with therapeutic concentrations of aspirin. Comparison of the yield of acetylated alpha-crystallin with the yield of carbamylated alpha-crystallin that might occur due to renal failure indicates that aspirin is not likely to be an effective inhibitor of cataract due to carbamylation of lysyl residues.

Acetylation↗
PubMed1993

Heart-lung transplantation combined with correction of interrupted aortic arch.

We describe a new technique for heart-lung transplantation in a patient with interrupted aortic arch. The operation was performed in a 21-year-old patient with situs solitus, double-inlet left ventricle, transposition of great arteries, type A interrupted aortic arch, and pulmonary hypertension. One-stage correction of interrupted aortic arch was undertaken using recipient ductal and pulmonary arterial tissues. The early postoperative course was uneventful, with clinical and radiological evidence of satisfactory result. We conclude that it is entirely feasible to undertake heart-lung transplantation in the presence of interrupted aortic arch using this technique, which requires no period of circulatory arrest and results in a tension-free anastomosis.

Adult↗
PubMed1993

Orthotopic heart transplantation for congenital heart disease. Technical considerations.

Heart transplantation for congenital heart disease poses unique problems because of structural anomalies and previous corrective and palliative surgery. In the period between May 1985 and February 1992 a total of 231 orthotopic heart transplants were performed at our hospital -22 of these procedures were carried out in patients with congenital heart disease. The patient's ages ranged from 1 month to 51 years (median 10 years). There were 13 patients in the paediatric group (under 16 years) and 9 patients in the adult group (16 years or older). The diagnoses included univentricular connections (8 patients), complex morphology (4 patients), congenitally corrected transposition of the great arteries (TGA) (3 patients), hypoplastic left heart syndrome (2 patients), Fallot's tetralogy, tricuspid atresia, TGA, pulmonary atresia with intact ventricular septum and atrial septal defect (ASD) and ventricular septal defect (VSD). These patients had protected pulmonary circulation due to previous surgery or as a result of intrinsic pulmonary stenosis. Seventeen patients (77%) had undergone 29 prior operations (21 palliative and 8 corrective) including Blalock-Taussig shunts, pulmonary artery (PA) banding, ASD and VSD repair, Fontan procedure and Mustard operation. There were 2 early deaths in the paediatric group and 4 early deaths in the adult group, but no late deaths. The cause of death was multi-organ failure following uncontrollable haemorrhage in 3 patients, sepsis in 1 patient and donor organ failure in the 2 paediatric patients. Specific surgical manoeuvres were required to create the normal anatomical configuration. These included the rerouting of venous circulation, pulmonary artery reconstruction and atrial septation. Adequate donor tissue was taken to permit satisfactory reconstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Penetration of ciprofloxacin into pleural fluid.

The penetration of oral 1000 mg/day ciprofloxacin into pleural fluid is investigated in 15 patients with exudative pleural effusion. After 4 days of ciprofloxacin therapy ciprofloxacin concentrations were measured in plasma and pleural exudate simultaneously by high-performance liquid chromatography (HPLC). Mean serum ciprofloxacin level was 1.58 +/- 0.91 mg/L and mean pleural exudate concentration was 1.00 +/- 0.59 mg/L. The concentrations achieved were all above the MIC90 of the majority of Gram-positive and Gram-negative pathogens. It is concluded that ciprofloxacin penetrates well into the pleural fluid.

Adolescent↗
PubMed1993

[Outcome of conservative treatment of high-degree vesicoureteral reflux].

We performed a retrospective study to evaluate the results of a nonsurgical approach of primary high grade vesicoureteral reflux (VUR). 241 patients (209 III and 32 IV) were reviewed during and average time of 9.4 years. 55% of them were under 6 months and 52% had bilateral reflux (50% III and 63% IV). During the observation period spontaneous resolution of reflux was observed in 126 (60%) with grade III at 5 years and 26% in patient with grade IV at 4 years. In both grades the duration of persistent reflux was analyzed using life-table method. When age at presentation was compared with duration of reflux there was a shorter time of reflux in those patients presenting from age 0 to 6 months. New renal scars developed in 5 patients during the period of observational therapy. We conclude that high grade VUR can resolve over a protracted interval. On basis of this analysis, we advocate the surgical correction in these patients after 5-year period to grade III and 2-year to grade IV.

Child↗
PubMed1992

Synthesis and biological studies of unsaturated acyclonucleoside analogues of S-adenosyl-L-homocysteine hydrolase inhibitors.

The design, synthesis, and biological evaluation of several unsaturated acyclonucleosides related to augustmycin A are described. The (propargyloxy)methyl acyclonucleoside analogues of 6-chloropurine, adenine, 6-methoxypurine, hypoxanthine, 6-mercaptopurine, and azathioprine have been prepared. The 9-[(propargyloxy)methyl]adenine (5) and 9-[(propargyloxy)methyl]hypoxanthine (12) analogues were converted to the corresponding 5'-tributylstannyl intermediates (9 and 13), respectively, which gave 9-[[[(Z)-5-iodo-5-propenyl]oxy]methyl]adenine (10) and 9-[[[(Z)-5-iodo-5-propenyl]oxy]methyl]hypoxanthine (14), respectively, after iododestannylation. The [125I]-radiolabeled congeners of 10 and 14 were prepared as potential metabolic markers. Among the unsaturated acyclonucleosides tested, 9-[(propargyloxy)methyl]-6-chloropurine (3), 9-[(propargyloxy)methyl]-6-mercaptopurine (15), 9-[(propargyloxy)methyl]azathioprine (17), and angustmycin A analogue 10 showed inhibition of cancer cell growth, but only at a minimal level, and 17 also showed 14% cancer cell death in vitro. Compound 10 provided approximately 50% protection against HIV at 10(-4) M concentrations. Biodistribution results of [125I]-10 in mice indicate that compound 10 is readily metabolized via deiodination in vivo, possibly by serving as a substrate for the enzyme S-adenosyl-L-homocysteine hydrolase.

Adenine↗
PubMed1988

Controlled trial of intravesical noxythiolin in the prevention of infection following outflow tract surgery.

A randomised control trial was undertaken in 100 consecutive patients undergoing endoscopic surgery for outflow tract obstruction to assess the efficacy of noxythiolin in preventing post-operative bacteriuria; 1% noxythiolin or sterile water was instilled at the time of catheter removal. The incidence of bacteriuria in the treated group (7/50) was significantly lower than in the control group (19/50). This was statistically significant. This difference was more marked in patients who had been catheterised for retention of urine. There was no difference in the complication rate despite a reduction of infection in the treated group.

Administration, Intravesical↗