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Biomedical subjects

N Ahmad

Publications and source records attributed to N Ahmad.

At least 163 records · Page 9Linked to original sources
PubMed1994

The prevalence of hepatitis C virus (HCV) in infants and children after liver transplantation.

Hepatitis C virus (HCV) is an important cause of liver injury following liver transplantation in adults. We hypothesized that the prevalence of HCV infection in children following liver transplantation would be lower than the prevalence in adults after liver transplantation because HCV-related liver disease leading to liver transplantation in children is low and children require less blood products than adults during transplantation. We therefore performed a cross-sectional study to determine the prevalence of HCV infection in children who had undergone liver transplantation. Serum samples were obtained from 62 of 65 (95.4%) consecutive patients surviving for more than six months after transplantation. Using a second-generation enzyme-linked, immunosorbent assay (ELISA-2) and a second-generation recombinant immunoblot assay (RIBA-II), antibodies to HCV were detected in 5.1% (3 of 59) of the subjects. Using a single-step, polymerase chain reaction (PCR), HCV RNA was detected in 6.2% (4 of 62). All HCV-positive children had undergone liver transplantation before the initiation of routine screening for HCV in blood donors; overall 30 patients were transplanted prior to routine screening of blood products for HCV. The prevalence of HCV in infants and children after liver transplantation in our study is substantially less than the rates reported in adults. This difference may be due, in part, to the lower volume of blood product exposure and to the fact that children, as opposed to adults, rarely have chronic HCV infection as a cause of end-stage liver disease.

Adolescent↗
PubMed1994

Suppression of prostaglandin F2 alpha and oxytocin release after inhibition of testosterone synthesis in the goat.

Increased peripheral plasma concentrations of testosterone were detected in goats on days 13 and 14 of the oestrous cycle (oestrus = day 0), at the onset of luteolysis. Subcutaneous administration of spironolactone (10 mg kg-1 day-1) on days 10 to 19 inhibited the increases in testosterone, delayed luteolysis and suppressed plasma concentrations of 13,14-dihydro-15-keto-prostaglandin F2 alpha and oxytocin. These results suggest that testosterone of follicular or luteal origin, possibly via aromatisation to oestrogens, is needed to expedite luteolysis and induce oestrus in the goat.

Animals↗
PubMed1994

Prostaglandin F2 alpha-induced release of oxytocin from ovine corpora lutea in vitro.

Prostaglandin (PG)F2 alpha, in the dose range 1-10(4) nM, failed to elicit oxytocin secretion in vitro from ovine luteal tissue on day 12 of the estrous cycle (estrus = Day 0), during a 60 minute period. Preincubation of luteal slices for 6 hours prior to treatment suggested that tissue desensitization due to the release of endogenous prostaglandins by tissue preparation is not responsible for this lack of response. However, in luteal tissue collected on day 6 of the ovine estrous cycle, PGF2 alpha stimulated oxytocin release in a dose-dependent manner. This apparent change in sensitivity of the ovine corpus luteum in vitro may be due to a combination of a reduction in the luteal oxytocin available for release and saturation of PGF2 alpha receptors in the more mature tissue.

Animals↗
PubMed1994

Potential role for lipoxygenase products of arachidonic acid in prostaglandin F2 alpha-stimulated oxytocin release from the ovine corpus luteum.

Intrauterine administration of nordihydroguaiaretic acid (NDGA) will maintain luteal function in sheep and also suppress the release of both oxytocin and prostaglandin F2 alpha (PGF2 alpha) suggesting that 5-lipoxygenase products of arachidonic acid may be involved in ovine luteolysis. During luteolysis, uterine PGF2 alpha is considered to be the major stimulus for the secretion of luteal oxytocin, and we report the effects of 5-lipoxygenase inhibition, via intrauterine NDGA administration, on the ability of PGF2 alpha to effect such secretion. In the NDGA-treated ewes, luteal function was maintained and oestrus delayed, the duration of the oestrous cycle (20 +/- 1 days; mean +/- S.D.; n = 9) being significantly (P < 0.01) longer than in intact controls (15 +/- 1 days, n = 4). Jugular infusions of PGF2 alpha did not stimulate luteal secretion of oxytocin, the effects being comparable with those in ovariectomized ewes. In intact ewes receiving intrauterine infusions of vehicle only, PGF2 alpha produced marked increases in luteal secretion of oxytocin. Also, preinfusion or basal concentrations of oxytocin in this group of ewes (6.6 +/- 1.9 pg/ml) were significantly (P < 0.01) greater than in either the NDGA-treated (3.1 +/- 1.1 pg/ml) or ovariectomized (3.0 +/- 0.6 pg/ml) ewes. The results suggest involvement of 5-lipoxygenase products of arachidonic acid in the release of oxytocin from the ovine corpus luteum.

Animals↗
PubMed1994

Isolation of Moraxella catarrhalis from sputum specimens of Malaysian patients.

Moraxella catarrhalis has gained reputation as a pathogen in the lower respiratory tract especially in patients with underlying chronic lung diseases. It is considered significant when isolated from sputum specimens of adults with respiratory tract infections. A study was carried out to determine the prevalence of Moraxella catarrhalis isolated in sputum specimens and beta-lactamase production of these isolates. Sputum specimens sent to the Bacteriology division, Institute for Medical Research from April 1990 until April 1993 were screened for Moraxella catarrhalis. A total of 1678 sputum specimens were processed and Moraxella catarrhalis was isolated from 15 (0.89%) of the sputum specimens. Six out of 15 (40%) were isolated from patients with chronic lung disease. Eight out of 15 (47%) were beta-lactamase producers. Moraxella catarrhalis isolated in good-quality sputum must not be disregarded and should be looked for especially in patients with chronic obstructive pulmonary disease. Beta-lactamase production should be tested on all isolates so that appropriate treatment can be given. All the isolates in this study were sensitive to cotrimoxazole.

Adolescent↗
PubMed1994

A new approach to aortic annulus enlargement.

Enlargement of the aortic annulus has always been a dilemma. Many techniques have been suggested. We present a new technique which was carried out on 43 patients which caused symptomatic improvement in those patients. The technique includes incising the aortic annulus at both ends of the left coronary cusp or both sides of the left coronary ostium of equal distance. Prosthetic or pericardial patches are used for enlargement. We have had good results with this technique and we believe it is an excellent alternative to prevent late complications on mitral valve.

Aortic Valve↗
PubMed1993

A selective approach to adjunctive therapy for cancer of the rectum.

PURPOSE: To present results of a selective approach to adjunctive therapy and surgery based on a new model of clinical staging for rectal cancer. METHODS AND MATERIALS: Three hundred and sixty-two patients with rectal cancer treated with adjunctive radiation therapy and surgery have been analyzed to define patient selection criteria based on clinical assessment of disease. Clinical prognostic features of tumor mobility and level of lesion in the rectum with reference to the anorectal junction were used. Mobile, early fixed (partial), advanced fixed (total) and frozen pelvis are defined as clinical Stages I, II, III, and IV. Tumors above 6 cm (middle valve), 3-6 cm (inferior to middle valve), 0-3 cm (anorectum to inferior valve), and into the anal canal are defined as levels a, b, c, d, respectively. Based on this model, patients with mobile tumors of the proximal rectum (CS Ia, b) are treated with 500 cGy preoperative radiation and selective postoperative radiation (4500 cGy) for Stages B2 and C cancer. All other patients are treated with escalating doses of preoperative radiation. Follow-up in these patients ranges from 1 year to 14 years with a median of 5 years. RESULTS: Overall 5-year survival of the total group of patients is 69%. Survival by pathological stage is 82% for O, A, B1, 67% for B2, 74% for C1, and 51% for C2. Survival by clinical stages is 77% for CS I, 67% for CS II, 57% for CS III, and 21% for CS IV. Overall local recurrence is 43/362 (12%). L.R. by pathological stages is 5% for O, A, B1, 18% for B2, 10% for C1, and 17% for C2. L.R. by clinical stages is 9% for CS I, 14% for CS II, 17% for CS III, and 50% for CS IV. CONCLUSION: An integrated adjunctive therapy and selective surgical approach based on careful clinical staging of rectal cancer results in a global improvement in overall local control and survival of patients.

Adenocarcinoma↗
PubMed1993

Use of ultrasound to diagnose testicular degeneration in a goat.

A seven-year-old infertile British alpine buck with small testes had bilateral testicular degeneration, as confirmed by the presence of a large number of dead and abnormal spermatozoa and a low percentage of progressively motile spermatozoa in its semen. Histopathological examination of the testes post mortem showed typical degenerative changes in the seminiferous tubules, with some tubules showing evidence of calcification. Ultrasonographically, the testicular parenchyma was uncharacteristically heterogeneous with an abundance of dense echogenic areas scattered through it.

Animals↗
PubMed1993

Potentiometric stripping analysis of selected heavy metals in biological materials.

Different biological materials such as edible oils, refined and unrefined cane and beet sugar and tea (black and green) leaves were assayed for the heavy metals cadmium, copper, lead and zinc. The results revealed significant differences in heavy metal contents within each class of the biological materials (P < 0.05). Cadmium was not detectable in sugar samples. Among the oils, highest amounts of copper (0.263 microgram/g) and lead (0.154 microgram/g) were in corn oil and zinc in olive oil (3.01 micrograms/g) whereas cadmium exhibited a narrow range (0.023-0.033 microgram/g). The samples of beet-sugar generally contained higher levels of the heavy metals than cane-sugar. Black and green tea leaves contained 0.411-0.908 microgram Cd/g, 6.500-9.220 micrograms Cu/g, 2.200-5.238 micrograms Pb/g, and 14.500-25.180 micrograms Zn/g.

Carbohydrates↗
PubMed1993

Detection of viremia by a one step polymerase chain reaction method in hepatitis C virus infection.

A simple, sensitive, and specific one step polymerase chain reaction (PCR) method for the detection of hepatitis C virus (HCV) RNA in infected patients' serum or plasma samples is described. We performed the one step PCR amplification in combination with the initial step of reverse transcription by using oligonucleotide primers derived from the conserved 5'-untranslated region (5'-UTR) of the HCV genome. By utilizing this strategy, there was no need for nested or second stage PCR amplification. The PCR products (cDNAs) were easily visualized by agarose gel electrophoresis and ethidium bromide staining. Furthermore, the PCR products were characterized by Southern blot hybridization and DNA sequencing. We then used the one step PCR amplification method to detect the presence of HCV RNA in several infected patients' samples with acute and chronic infections. There was a 100% concordance between the results of PCR and second generation recombinant immunoblot assay (RIBA II). In addition, this method was found to be useful in determining viremia in HCV infected patients with indeterminate RIBA II results. The 5'-UTR of the HCV genome, being the most conserved region among different viral isolates, could be amplified by PCR for the detection of HCV RNA, as shown here, as well as serving as a potential target for antiviral agents.

Base Sequence↗
PubMed1993

A ribonuclease protection assay for the direct detection and quantitation of hepatitis C virus RNA.

A ribonuclease protection assay (RPA) was developed for the direct detection and quantitation of HCV RNA in infected patients' sera or plasma using HCV [(32)P]RNA from the conserved 5'-untranslated region (5'-UTR) as a probe. We were able to directly detect the presence of HCV RNA by RPA in several infected patients' samples. The viremic status of HCV infected patients with indeterminate recombinant immunoblot assay (RIBA II) was also determined by this assay. Polymerase chain reaction (PCR) was also performed on all these samples and were found to be positive with a concordance of 100% between the results of PCR and RPA. The RPA was able to detect approximately 1 pg of HCV RNA. A limited sequence heterogeneity among HCV isolates was also observed by this assay, suggesting that this may be a faster method of detecting heterogeneous HCV sequences in patients' samples. This simple and specific method could be used to quantitate HCV RNA in order to better determine viremia and follow the course of HCV infection especially when RIBA II results are indeterminate.

Journal Article↗
PubMed1993

Medicolegal practice in Pakistan. A view from within.

Two generations have passed since Pakistan changed constitutionally from being under the rule of the British monarchy to becoming an independent Islamic-based democratic republic. Its medicolegal system, including the administration of justice, the academic basis of its medical and scientific expertise, and the practical investigation of crime, is thus a conglomerate of the English legal system and traditionally orientated and religiously based addenda that were successfully grafted onto the preexisting codes. With increasing urbanization, the greater availability of education, and specialization, further changes are likely that will mirror ongoing developments and activities in medicolegal practice worldwide. An overview of the Pakistani medicolegal system as it now exists is presented here to enable a better understanding of the changes that are gradually occurring and that need to continue.

Criminal Law↗
PubMed1993

Impaling-type head injury in a road traffic incident.

A fatal impaling-type head injury is described in a young man, sustained when he crashed his car while intoxicated, his head being transfixed by a broken wooden fence post. This shattered the facial bones and damaged the brain stem. Other published instances of impaling head injuries are discussed.

Accidents, Traffic↗