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Biomedical subjects

F Hassan

Publications and source records attributed to F Hassan.

At least 19 recordsLinked to original sources
PubMed2004

Hepatitis C virus infection in asymptomatic male volunteer blood donors in Karachi, Pakistan.

The objectives of this study were to assess the proportion of hepatitis C virus (HCV) reactors and to identify risk factors associated with HCV infection in volunteer blood donors in Karachi, Pakistan. Between 1 January 1998 and 31 December 2002, consecutive blood donations tested at two blood banks were used to assess the proportion of HCV sero-reactors donors. To evaluate the potential risk factors, a case-control study design was implemented to select cases and controls between 15 October 2001 and 15 March 2002. The overall seroprevalence of HCV in these blood donors was 1.8% (6349/35 1309). Trend analysis revealed a significant (P < 0.001) linear increase in proportions of HCV-seropositive donors from 1998 to 2002. Final multivariate logistic regression model showed that the cases were more likely than controls to have reported past hospitalization or to have received multiple injections. When a glass syringe was used to give therapeutic injections, it increased the adjusted odds of being HCV seropositive significantly more among cases than in controls and this relationship was stronger when injection was given by general medical practitioner than if the injection was given in hospital setting. Cases were more likely than controls to have reported sexual contact with multiple sexual partners. Primary prevention programmes focused on identified risk factors might help to curtail the spread of HCV infection in this community and in other similar settings in developing countries.

Adolescent↗
PubMed2001

Altering trends in the dominance of Shigella flexneri serotypes and emergence of serologically atypical S. flexneri strains in Dhaka, Bangladesh.

Of 469 recently isolated Shigella flexneri strains, 452 agglutinated with Shigella flexneri-specific monoclonal antibodies. Of these, 396 could be assigned to 10 of the currently recognized 15 serotypes, with S. flexneri 2b dominating (23.2%). Of the 56 untypeable strains which showed invasive properties, 17 were serologically atypical and the remaining 39 belonged to a new serotype.

Bacterial Typing Techniques↗
PubMed2001

Evaluation of Acetaminophen tablets by control test.

Various pharmacopoeial and non-pharmacopoeial control test applied to Acetaminophen tablets were used to evaluate for the uniformity of weight, diameter, thickness, medicaments, hardness and friability. The tests were intended to check the compliance of the prepared tablets with the accepted specifications.

Journal Article↗
PubMed2000

Dissolution rate studies on Acetaminophen tablets.

The effect of disintegrants on the dissolution rate of Acetaminophen tablets at different hardness has been investigated. It was determined that the dissolution rate is influenced by disintegrants as well as hardness for all formulations except in tablets containing Veegum as the disintegrant.

Journal Article↗
PubMed1999

The cross cultural context of obesity: an INCLEN multicentre collaborative study.

Associations between obesity and cardiovascular disease have been documented in the Developed World and have been linked with levels of 'development' in Developing World countries. This study aimed to explore the sociocultural influences on attitudes towards obesity, physical activity and dietary change using a four level conceptual framework (from personal to societal influences). Focus group discussions were conducted in: India, Indonesia, Cameroon, Egypt and Australia. The results of these discussions were analysed to reveal emergent themes. The interpretation of the qualitative data emphasised the need to incorporate influences beyond the individual in efforts to reverse or prevent obesity related disease.

Adult↗
PubMed1999

Prevalence of hepatitis G virus in Pakistani children with transfusion dependent beta- thalassemia major.

We ought to obtain data on the prevalence of the newly discovered tranfusion transmittable hepatitis G virus in polytransfused b- thalassemia major children. Each individual had received multiple blood transfusions, from 12 to 36 per year. No documentation of prior hepatic infection was available. Serum samples were collected prospectively from the randomly selected subjects and were analyzed for HGV RNA by polymerase chain reaction using primer specific for two different regions of the HGV genome. Among the 100 individuals examined 21 were positive for HGV RNA. Four patients had evidence of dual infection, both HGV RNA and HCV RNA were isolated from their sera. While in one sample presence of both HGV RNA and HBV DNA was established. Only one child was positive for hepatitis E antibodies. The sera of 10 children were reactive for hepatitis B surface antigen whereas 35 individuals were positive for hepatitis C virus antibody. The ALT levels were variable in HGV infected children. Four out of 16 (25%) showed peak ALT levels of 218 IU/I, 8/16 (50%) children demonstrated slightly elevated ALT levels whereas 25% individuals showed normal ALT levels. Alkaline Phosphatase levels were elevated in 90% of the children and 20% patients of this series also had higher GGT levels. The observed AP levels were not statistically different among HGV, HGV/HCV or HGV/HBV groups. Even though the ALT levels were deranged in the children with HGV alone but none of the children had demonstrated symptoms of liver disease, their direct and total bilirubin levels were normal and no complain of jaundice was recorded. In conclusion, our findings suggested that like other blood borne hepatic viruses, HGV is also prevalent in the high risk group of multiple transfused patients in Pakistan but our results support the absence of any causal relationship between HGV and hepatitis.

Blood Transfusion↗
PubMed1998

A novel Glu421Lys substitution in the lipoprotein lipase gene in pregnancy-induced hypertriglyceridemic pancreatitis.

Severe hypertriglyceridemia is an uncommon pathological finding in pregnant women if there is no prior history of hyperlipidemia. A partial reduction in lipoprotein lipase (LPL) activity due to a mutation in the LPL gene, is often an associating factor. Here we report a novel LPL gene mutation (Glu421Lys), in a previously healthy primigravid woman who died from hypertriglyceridemia-induced pancreatitis during the last trimester of pregnancy. The patient was heterozygous for this mutation which a charge inversion in the C-terminal domain of LPL resulting in a moderate reduction in catalytic activity, both in vivo and in vitro. These data support the role of partial LPL deficiency in the pathogenesis of severe gestational hypertriglyceridemia.

Adult↗
PubMed1998

Effects of pulsed high-frequency electromagnetic fields on the neuroendocrine system.

The influence of pulsed high-frequency electromagnetic fields emitted from a circularly polarized antenna on the neuroendocrine system in healthy humans was investigated (900 MHz electromagnetic field, pulsed with 217 Hz, average power density 0.02 mW/cm2). Nocturnal hormone profiles of growth hormone (GH), cortisol, luteinizing hormone (LH) and melatonin were determined under polysomnographic control. An alteration in the hypothalamo-pituitary-adrenal axis activity was found with a slight, transient elevation in the cortisol serum level immediately after onset of field exposure which persisted for 1 h. For GH, LH and melatonin, no significant effects were found under exposure to the field compared to the placebo condition, regarding both total hormone production during the entire night and dynamic characteristics of the secretion pattern. Also the evaluation of the sleep EEG data revealed no significant alterations under field exposure, although there was a trend to an REM suppressive effect. The results indicate that weak high-frequency electromagnetic fields have no effects on nocturnal hormone secretion except for a slight elevation in cortisol production which is transient, pointing to an adaptation of the organism to the stimulus.

Adolescent↗
PubMed1998

Viscosity studies on Mestranol.

The viscosity of 1x10(-4) M to 4x10(-4) M solution of Mestranol (synthetic oestrogenic steroidal hormone) in ethanol was measured at 32 degrees, 40 degrees and 50 degrees C in a viscometric bath. The viscosity rates are maximum at 30 degrees C as compared to 40 degrees and 50 degrees C. The disappearance rate of Mestranol at higher temperature and lower viscosity is due to triplet state of species transitions at higher thermal conditions.

Journal Article↗
PubMed1996

A new mutation destroying disulphide bridging in the C-terminal domain of lipoprotein lipase.

Lipoprotein lipase (LPL) is one of two intravascular lipases involved in the lipolysis of the triglyceride core of circulating lipoproteins. The occurrence of patients with genetic deficiencies has provided insight into the structure and function relationships of this lipase. It is now known that LPL manifests a two domain structure with the N-terminal domain of greater structural and functional significance as it contains the active site and interfacial binding motifs. We report on a Cys418Tyr substitution in the C-terminal domain which disrupts the only disulphide bridge in the region and is associated with catalytic deficiency in post-heparin plasma. This result was unexpected as previous in vitro assessment of the functional significance of disulphide bridging had shown that while the 3, N-terminal disulphides were critical for enzyme function, loss of the only C-terminal disulphide minimally affected catalytic activity. We generated the Cys418Tyr mutant by site-directed mutagenesis and show that it manifests 48% of normal activity in vitro, while the companion variants, Cys438Ser and Cys418Ser-Cys438Ser, are less affected with activities at 76% and 78% of normal.

Adult↗
PubMed1996

A comparative study and behaviour of a series of cationic surfactants towards the degree of the basic hydrolysis of p-nitrophenyl acetate.

The surfactant effect of cationic micelles of Dodecyl, tetradecyl and hexadecyl trimethyl ammonium bromide, Cetyl pyridinium bromide, Cetyl dimethyl ethyl ammonium bromide and benzalkonium chloride on the hydrolysis of p-nitrophenyl acetate (PNPA), was studied. The effect of cationic surfactants was within concentration range of 1 x 10(-6) M - 1 x 10(-1) M, with the exception of benzalkonium chloride, where the concentration effect was investigated between 1 x 10(-6) M - 3 x 10(-1) M. All cationic micelles increased the rate of hydrolysis of PNPA upto their concentration of 1 x 10(-2) M and then the rate decreased while benzalkonium chloride showed this maximum at 5 x 10(-2) M. Orientation and adsorption of substrate at the micelle surface are put forwarded to explain this catalytic behaviour. An attempt has also been made to interpret the influence of cationic micelles on the basis of ion exchange model.

Journal Article↗
PubMed1995

Helicobacter pylori infection and dental care.

Sixty two patients (mean age 45.6 years) were assessed for oral hygiene and periodontal disease by dental examination before endoscopy. Information about oral care, smoking, and dentures was obtained and samples of dental plaque collected. The presence of Helicobacter pylori in plaque as sought by culture and polymerase chain reaction (PCR), and gastric antral biopsy specimens were taken for histological examination. Although H pylori was detected in the antral specimens of 34 patients (54%) all of the cultures of dental plaque were negative, and PCR was only positive from the dentures of one patient. Smokers had poor oral hygiene, visited their dentist less often, and brushed their teeth less frequently. There was no correlation of H pylori gastritis with either dental hygiene or periodontal disease. These results suggest that dental plaque or dentures are not an important reservoir for H pylori and are probably not a significant factor in transmission of the organism. The conflicting results in published works may be caused by differences in sample collection, culture techniques, or oral contamination from gastric juice as a result of gastro-oesophageal reflux at the time of endoscopy.

Adult↗
PubMed1993

Penetration of mitomycin C in human bladder.

The penetration of mitomycin C (MMC) in bladder tissue was studied in patients who received intravesical chemotherapy at the time of radical cystectomy. An intravesical dose of MMC (20 mg/40 ml) was instilled and maintained in the bladder for 60 to 120 min at which time the solution was drained. Within 10 to 60 min after draining the drug solution, the bladder vasculature was ligated, and the bladder was removed. Tissues were sectioned serially in layers parallel to the urothelium and analyzed for MMC concentration. Of the 24 patients evaluated, 17 patients had a low final MMC concentration in urine (< 66 micrograms/ml) or had the MMC solution drained more than 30 min before ligation of the blood vessels. Among these 17 patients, the concentration in the urothelium was measurable in only 4 patients, while the concentrations in deeper tissues were not measurable. In the remaining 7 patients where the urine concentration was > 120 micrograms/ml and where the vasculature was ligated within 30 min after the MMC solution was drained, the bladder wall contained significant MMC concentrations. The drug penetration was studied in the latter 7 patients, using sections of bladder wall that were grossly normal and non-tumor bearing. Concentrations in the bladder wall declined semilogarithmically with tissue depth from the urothelium to the deep muscle and reached a plateau at about 2000 microns depth. The median MMC concentrations were 5.6 micrograms/g in the urothelium and lamina propria interface, 2.7 micrograms/g in the lamina propria, and 0.9 microgram/g in the muscularis. The distance over which the MMC concentration decreased by one-half was about 500 microns. The concentration ratio between the urine and urothelium/lamina propria interface was about 35-fold. The mean plasma concentrations were 0.003, 0.1, and 0.4% of the mean concentration in urine, urothelium, and the averaged bladder tissue concentrations, respectively. Paired superficial tumor and normal tissues were obtained from 5 bladders. In 4 of 5 cases, the concentration in tumors was higher than in normal tissues, while the reverse was seen in the remaining tumor. In one sessile bladder tumor a complete concentration-depth profile could be obtained. While the concentrations in the tumor tissue were 2-3-fold higher than that in the adjacent normal tissue, the rate of concentration declined with respect to tissue depth and hence the distance over which the MMC concentration decreased by one-half was similar in both tumors.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Intravesical↗
PubMed1992

The lipoprotein lipase Gly188----Glu mutation in South Africans of Indian descent: evidence suggesting common origins and an increased frequency.

Lipoprotein lipase (LPL) plays a crucial role in the hydrolysis of the triglyceride core of circulating chylomicrons and very low density lipoproteins (VLDL) and also has a major effect on the levels and lipid composition of high density lipoproteins (HDL). LPL deficiency is inherited as an autosomal recessive trait and most commonly presents with chylomicronaemia, abdominal pain, and eruptive xanthomata. We have previously described a mutation in exon 5 of the LPL gene which results in a substitution of glutamic acid for glycine at amino acid 188. We have now assessed 16 South African LPL deficient patients from nine separate kindreds for this mutation. Nine of these probands were homozygous for the mutation and were from four families, all of Indian descent. The ancestors of these probands have their origins in villages close to Bombay, India, which suggests a common ancestral mutation for the four Indian kindreds, particularly as the mutant allele in each family carried the identical restriction fragment length polymorphism (RFLP) haplotype. The presence of at least nine affected subjects in this small community around Cape Town is evidence for a higher than expected gene frequency for LPL deficiency in this population.

Base Sequence↗
PubMed1988

Purification and characterization of pyocins R from Pseudomonas aeruginosa.

Five types of pyocins were found in Pseudomonas aeruginosa strain 112. Production of these types was induced by UV irradiation. The pyocin activity was found to be resistant to trypsin treatment. Their molar mass was found to be 282, 251, 112, 89.1 and 54.9 kg/mol, respectively. The pyocins obtained were different from any known type (such as R, S, F) in their chemical and physical properties.

Bacteriocins↗