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S H Hassan

Publications and source records attributed to S H Hassan.

At least 19 recordsLinked to original sources
PubMed2004

Genetic diversity of bluetongue viruses in south east Asia.

Bluetongue viruses (BTV) were isolated from sentinel cattle in Malaysia and at two sites in Indonesia. We identified eight serotypes some of which appeared to have a wide distribution throughout this region, while others were only isolated in Malaysia or Australia. Nearly half of the 24 known BTV serotypes have now been identified in Asia. Further, we investigated the genetic diversity of their RNA segments 3 and 10. Using partial nucleotide sequences of the RNA segment 3 (540 bp) which codes for the conserved core protein (VP3), the BTV isolates were found to be unique to the previously defined Australasian topotype and could be further subdivided into four distinct clades or genotypes. Certain of these genotypes appeared to be geographically restricted while others were distributed widely throughout the region. Similarly, the complete nucleotide sequences of the RNA segment 10 (822 bp), coding for the non-structural protein (NS3/3A), were also conserved and grouped into the five genotypes; the BTV isolates could be grouped into three Asian genotypes and two Nth American/Sth African genotypes.

Amino Acid Sequence↗
PubMed2001

Expression and functional characterization of bluetongue virus VP5 protein: role in cellular permeabilization.

Segment 5 of bluetongue virus (BTV) serotype 10, which encodes the outer capsid protein VP5, was tagged with glutathione S-transferase and expressed by a recombinant baculovirus. The recombinant protein was subsequently purified to homogeneity, and its possible biological role in virus infection was investigated. Purified VP5 was able to bind mammalian cells but was not internalized, which indicates it is not involved in receptor-mediated endocytosis. The purified VP5 protein was shown to be able to permeabilize mammalian and Culicoides insect cells, inducing cytotoxicity. Sequence analysis revealed that VP5 possesses characteristic structural features (including two amino-terminal amphipathic helices) compatible with virus penetration activity. To assess the role of each feature in the observed cytotoxicity, a series of deleted VP5 molecules were generated, and their expression and biological activity was compared with the parental molecule. VP5 derivatives that included the two amphipathic helices exhibited cytotoxicity, while those that omitted these sequences did not. To confirm their role in membrane destabilization two synthetic peptides (amino acids [aa] 1 to 20 and aa 22 to 41) encompassing the two helices and an additional peptide representing the adjacent downstream sequences were also assessed for their effect on the cell membrane. Both helices, but not the downstream VP5 sequence, exhibited cytotoxicity with the most-amino-terminal helix (aa 1 to 20) showing a higher activity than the adjacent peptide (aa 22 to 41). Purified VP5 was shown to readily form trimers in solution, a feature of many proteins involved in membrane penetration. Taken together, these data support a role for VP5 in virus-cell penetration consistent with its revelation in the entry vesicle subsequent to cell binding and endocytosis.

Animals↗
PubMed2000

Cancer incidence in Karachi, Pakistan: first results from Karachi Cancer Registry.

No cancer incidence data from Pakistan have been published in the 5 decades since independence. Incidence data for the period 1995-1997 from the population of the Karachi South district (1.7 million) are presented here. A total of 4,268 new cancer cases were registered during this period: 2,160 cases in males and 2,108 cases in females. Overall, 95.3% of the incident cases were microscopically verified. The incidence rates for all cancers combined were 80.5 per 100,000 (crude) and 136.7 per 100,000 (age- standardised rates [ASR]) for males and 91.8 (crude) and 163.2 per 100,000 (ASR) for females. In males, lung cancer (ASR 20.3) was the most frequently recorded malignancy followed by oral cavity (ASR 13.8) and larynx cancer (ASR 8.6). In females, breast was the most common site of cancer, accounting for one third of female cancers (ASR 51.7), followed by oral cavity (ASR 14.1) and ovarian cancer (ASR 10.2). Karachi reports the highest incidence of breast cancer for any Asian population, except Jews in Israel. Tobacco smoking is estimated to be responsible for 40% of cancers in males and tobacco chewing for a further substantial proportion of head and neck cancers.

Adolescent↗
PubMed2000

Prospective randomized study of transurethral vaporization resection of the prostate using the thick loop and standard transurethral prostatectomy.

OBJECTIVES: Transurethral vaporization resection of the prostate (TUVRP) is a recent modification of the standard transurethral prostatectomy (TURP). The procedure uses one of the novel, thick resection loops coupled to augmented electrocutting energy. We evaluated the safety and efficacy of TUVRP in comparison with TURP. METHODS: Sixty-eight patients with prostatic outflow obstruction were prospectively randomized between equal TUVRP and TURP treatment groups. Safety parameters evaluated included changes in serum hemoglobin, hematocrit, and sodium 1 and 24 hours after resection. Operative time, catheterization time, and incidence of complications were noted. Efficacy parameters included evaluation by the International Prostate Symptom Score and maximum flow rate. RESULTS: Patients of both groups were balanced for the different baseline variables. One hour after TURP, patients had significantly lower levels of hemoglobin, hematocrit, and sodium (P = 0.03, 0.03, and 0. 01, respectively). The prostate resection weight was similar in both groups; however, the difference in the mean operative time was significant (TUVRP group 42.4 minutes and TURP group 35.9 minutes, P = 0.02). The postoperative catheterization time was significantly shorter for the TUVRP group (23.1 +/- 10.3 versus 36 +/- 17.3 hours, P <0.0001). All patients were followed up for an average of 9 months. The International Prostate Symptom Score was 4 +/- 3.4 and 5.6 +/- 3.1 and the maximum flow rate was 19 +/- 6.5 and 15.2 +/- 10 mL/s for the TUVRP and TURP groups, respectively; these differences were statistically significant (P = 0.03 and 0.01, respectively). Complications included urethral strictures (6 patients) and delayed hemorrhage with clot retention (2 patients); no differences in the incidence of complications were noted between the two groups. CONCLUSIONS: The results of the present study have demonstrated that TUVRP is as safe and efficacious as TURP in the treatment of men with prostatic outflow obstruction. The shorter catheterization time observed after TUVRP may be clinically significant, considering the demand for lower morbidity profiles by patients. The longer operative time in TUVRP was related to the slower motion of the Wing electrode needed to add the advantages of electrovaporization.

Aged↗
PubMed2000

Extracorporeal shockwave lithotripsy for ureterolithiasis in patients with urinary bilharziasis: efficacy and variables that influence treatment outcome.

OBJECTIVES: Schistosomiasis affecting the ureter is commonly accompanied by ureteric dilatation with or without ureteric stricture and altered ureteric wall motility that can influence extracorporeal shockwave lithotripsy (ESWL) results. This study attempts to identify variables that may influence the outcome of ESWL in the treatment of ureterolithiasis in patients with urinary bilharziasis. PATIENTS AND METHODS: Forty-three patients with urinary schistosomiasis and ureterolithiasis treated with ESWL were reviewed. The study data include characteristics of patients, stones, urinary tract treated and details of ESWL treatment. RESULTS: Thirty-five patients (81.3%) were stone-free at 3 months. Multivariate analysis with logistic regression identified two significant variables that influenced treatment outcome, namely the presence of ureteric stricture (p = 0.004) and the ESWL voltage (p = 0.003). Ten ureteric strictures were encountered in 9 patients (21%), the majority of these were diagnosed post-ESWL when patients failed to pass well-fragmented stones in spite of pre-ESWL evaluation. CONCLUSIONS: In situ ESWL is a safe and effective first line of treatment for urinary stones in bilharzial ureters. The presence of concomitant bilharzial stricture is a significant variable which affects the treatment outcome. Every effort should be made to rule out and deal with possible complicating factors such as ureteric strictures in the pretreatment period.

Adult↗
PubMed2000

Granulosa cell tumor of the adult type: a case report and review of the literature of a very rare testicular tumor.

We report a case of testicular granulosa cell tumor of the adult type in a 48-year-old man. Microscopically, the tumor consisted of round to ovoid cells with grooved nuclei that were arranged in several patterns, including microfollicular, macrofollicular, insular, trabecular, gyriform, solid, and pseudosarcomatous. These cells demonstrated strong immunopositivity with MIC2 (O13) antibody, vimentin, and smooth muscle actin and focal positivity with cytokeratin. Although this type of sex cord-stromal tumor is relatively common in the ovaries, it is still extremely unusual in the testis, and it probably represents the rarest type of testicular sex cord-stromal tumor.

Biomarkers, Tumor↗
PubMed2000

Frequency of malignant solid tumors in children.

OBJECTIVE: To find out the frequency of malignant solid tumors in children (< 15 years). SETTING: All cases of pediatric malignant solid tumors which were diagnosed in the section of histopathology at the Aga Khan University Hospital, Karachi during the period of two years. METHODS: These tumors were initially evaluated on H&E stained sections and special stains were also performed whenever indicated. The undifferentiated tumors were evaluated immunohistochemically by using a panel of antibodies on sections from routinely processed, formalin fixed, paraffin embedded tissue blocks. RESULTS: Of two hundred and fifty three (253) consecutive cases of paediatric malignant solid tumors, lymphoma (26.1%) was the most common tumor followed by central nervous system tumors (16.6%), osteosarcoma (7.5%), rhabdomyosarcoma (6.7%), neuroblastoma (5.1%), Wilm's tumor (5.1%), Ewing's sarcoma (4.7%), retinoblastoma (4.7%), germ cell tumor (4.4%) and primitive neuroectodermal tumor (4%) in order of frequency. In seven cases (2.8%), the nature of lesion remained undetermined even after immunohistochemical staining. Rest of malignant tumors (12.3%) included the rare entities like synovial sarcoma, nasopharyngeal carcinoma, leiomyosarcoma, malignant schwannoma and thyroid carcinoma, etc. CONCLUSION: Lymphoma was the most frequent Paediatric tumor. The frequency of childhood central nervous system tumors was quite high as compared to the other series from different regions of Pakistan.

Adolescent↗
PubMed2000

Childhood non-Hodgkin's lymphoma: an immunophenotypic analysis.

OBJECTIVE: To observe the frequency of histological subtypes of childhood non-Hodgkin's lymphoma and its immunohistochemical profile. SETTING: All cases of non-Hodgkin's lymphoma diagnosed in children (< 15 years) in the section of histopathology at the Aga Khan University Hospital Karachi during the period of three years. METHODS: These consecutive cases were evaluated on H&E stained sections and then immunohistochemistry analysis of these tumors was performed by employing Peroxidase Anti-Peroxidase (PAP) technique. RESULTS: The present series included 61 cases of non-Hodgkin's lymphoma. NHL was more common in males as compared to females with male to female ratio of 5.8:1. High grade NHL comprised 87% of childhood lymphoma. The mode of presentation in majority of NHL (57%) was extranodal. Burkitt's lymphoma (33%) was the most prevalent histological subtypes, followed by lymphoblastic (28%), diffuse large cell (15%), diffuse mix small and large cell (13%), small non cleaved Non-Burkitt's (7%) and immunoblastic (4%). Immunophenotypic analysis of the childhood Non-Hodgkin's lymphoma revealed that 67% of the Non-Hodgkin's lymphoma are B-cell type while 33%, are those of T-cell lineage. CONCLUSION: NHL was more common in males. Majority of NHL in children were high grade tumors. Burkitt's lymphoma was the most frequent histological subtype. T-cell NHL comprised a significant portion of childhood lymphomas.

Adolescent↗
PubMed1999

Clinico-morphological pattern of intracranial tumors in children.

OBJECTIVE: The objective of present study was to observe the histopathological pattern of intracranial tumors in children (< 15 yrs) and to correlate the site of lesion along with the histological diagnosis. SETTING: The study included consecutive cases of intracranial tumors diagnosed in children (< 15 yrs.) in the section of histopathology at the Aga Khan University Hospital, Karachi during the period of three years. METHODS: The initial histological evaluation of these lesions was performed on H and E stained section of paraffin embedded tissue. Special stains and immunohistochemical analysis was done whenever indicated. RESULTS: During the study period, fifty-four cases of intracranial tumors were diagnosed in children. The age ranged from 1-1/2 years to 4 years with male to female ratio of 1.1:1. Astrocytoma comprised 39% of all intracranial tumors of childhood. Medulloblastoma (18.6%) ranked the second most prevalent brain tumor followed by empendymoma (13%), oligodendroglioma 7.5% while non-Hodgkin's lymphoma, primitive neuroblastoma 3.7% and ganglioglioma 3.7% while non-Hodgkin's lymphoma, primitive neuroectodermal tumors, mixed germ cell tumor, pineoblastoma, choroid plexus carcinoma and malignant meningioma constituted 1.8% each. CONCLUSION: Astrocytoma was the most common pediatric brain tumor. Medulloblastoma was more common in males while pilocytic astrocytoma was more frequent in females. Posterior cranial fossa was the most common site (43.5%) of pediatric brain tumors. Low grade astrocytoma was more prevalent in posterior cranial fossa as compared to high grade astrocytoma which was more frequent in the supratentorial region.

Astrocytoma↗
PubMed1999

Immunohistochemical evaluation of small round cell tumors of childhood.

OBJECTIVE: This study was done to evaluate the pediatric undifferentiated small round cell tumors with immunohistochemical staining. SETTING: The present study included consecutive cases of small round cell tumors which were diagnosed in children (< 15 years) in the section of Histopathology at the Aga Khan University Hospital, Karachi during the period of two years. METHODS: The group of undifferentiated small round cell tumors were evaluated immunohistochemically by using a panel of antibodies on sections from routinely processed, formalin fixed, paraffin embedded tissue blocks. RESULTS: The category of undifferentiated small round cell tumors included rhabdomyosarcoma (23.2%), primitive neuroectodermal tumor (17.9%), non-Hodgkin's lymphoma (16.1%), neuroblastoma (14.2%), Ewing's sarcoma (10.7%) in order of frequency. Osteosarcoma (Small cell variant), retinoblastoma and medulloblastoma comprised 1.8% each. In seven cases (12.5%), the immunohistochemical analysis was inconclusive. CONCLUSION: Immunohistochemistry is a very valuable diagnostic tool which helps in distinguishing the undifferentiated tumors especially small round cell tumors. The immunohistochemical staining needs to be performed routinely for undifferentiated tumors in diagnostic histopathology.

Adolescent↗
PubMed1998

Incidence of carcinoma of the oral cavity in Karachi--district south.

Globally oral cancer is one of the ten common cancers. In some parts of the world, including the Indian sub-continent oral cancer is a major problem. The two year data of the Karachi Cancer Registry, showed oral cancer was the second most common malignancy in the males as well as in the females. The most common malignancy amongst the males being the carcinoma of the lungs and amongst the females, carcinoma of the breast. The annual incidence rate of oral cancer was 4.1 per 100,000 annually for the males and 4.0 per 100,000 annually for the females.

Adolescent↗
PubMed1997

Fine needle aspiration cytology in parotid lumps.

Over a period of two years, Fine Needle Aspiration Cytology (FNAC) was performed on 33 patients presenting with a parotid lump. Five patients were excluded as they were treated medically after FNAC report. The FNAC results of 28 cases were compared with histopathological diagnoses of surgically resected specimens. There were 8 true positive, 17 true negative, 1 false positive and 2 false negative cases. Sensitivity was 80%, specificity 94.4% and diagnostic accuracy 89.3%. FNAC is a simple quick, accurate and virtually complications free investigative modality. It is also helpful adjunct to assess preoperatively the suitability and extent of the surgical treatment.

Adolescent↗
PubMed1994

Role of vitamin A in modulating the radiation-induced changes in intestinal disaccharidases of rats exposed to multifractionated gamma-radiations.

PURPOSE: The aim of this investigation was to determine whether pre- or post-administration of vitamin A will be effective in reducing the radiation-induced alterations in intestinal disaccharidases in rats. MATERIAL AND METHODS: Rats were subjected to fractionated whole-body irradiation (20 x 0.5 Gy). Intestinal lactase activity as well as maltase and sucrase activities were assessed. Vitamin A was administered at daily intraperitoneal dose of 15,000 IU/kg body weight for 7 days prior to radiotherapy and thereafter twice weekly throughout therapy up to 7 days post irradiation. RESULTS: In irradiated rats a marked decrease in intestinal lactase activity to about one-fourth of those in non-irradiated rats was observed. In addition, a significant reduction in maltase and sucrase activities to one half of the control group was observed. The application of vitamin A significantly improved the radiation-induced inhibition of intestinal enzymes. Pretreatment application of vitamin A is more efficient to protect against radiation injury than a posttreatment application. CONCLUSIONS: The usage of vitamin A for modulation of radiation-induced changes in intestinal enzymes provides sufficient protection against treatment side effects induced by large volume radiotherapy.

Animals↗
PubMed1991

Cervical cancer screening program in a Muslim country: three-year experience at the Aga Khan University Medical Center, Karachi.

A systematic cervical cancer screening program was initiated in January 1987 at The Aga Khan University Medical Center, Karachi, Pakistan. The 8,784 cervical smears obtained in 3 subsequent years from 8,412 consecutive women attending the gynecology and antenatal clinics were reviewed. "Positive" smears were found in 111 (1.3%) patients; 107 (1.27%) smears showed squamous epithelial dysplasia and 4 smears showed adenocarcinoma. The highest incidence of abnormal smears was found in the 45-54 years age group. Colposcopy and biopsy was performed on all patients with "positive" smears except on those with atypical or mildly dysplastic ones, in whom only the persistence of the abnormality on repeated smears was considered an indication for tissue evaluation. The histopathologic diagnosis of these biopsy specimens revealed cervical intra-epithelial neoplasia in 60 patients and invasive cervical cancer in 6 patients.

Adenocarcinoma↗