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Biomedical subjects

Z Ahmad

Publications and source records attributed to Z Ahmad.

At least 19 recordsLinked to original sources
PubMed2006

Pacific Islands families study: the prevalence of chronic middle ear disease in 2-year-old Pacific children living in New Zealand.

OBJECTIVE: The aim of this study was to determine the prevalence of chronic middle ear disease in 2-year-old Pacific children living in New Zealand. METHODS: The data were gathered as part of the Pacific Islands Families: First Two Years of Life (PIF) Study in which 1001 two year olds were screened using tympanometry to identify children at risk for otitis media with effusion (OME) and other otological disorders. Those failing the screening tests were referred to Manukau Superclinic where they had a further tympanometry test, and if they failed this test, were followed up with a comprehensive otological examination by an otolaryngologist using otomicroscopy and pneumatic otoscopy. RESULTS: Bilateral otitis media with effusion (OME) was the most common abnormality detected (N=102) with further cases of unilateral OME (N=8), and unilateral OME resolving (N=2). Other cases of OME were associated with acute otitis media (AOM), impacted wax (N=1), perforation (N=1), and mild retraction (N=2). Overall there were 118 children with unilateral or bilateral OME. AOM of any form was seen in nine cases. Retraction of the tympanic membrane was seen in 26 cases. The population prevalence among Pacific 2-year-old children was estimated as 25.4% for OME, 1.9% for AOM, and 26.9% for OME or AOM. CONCLUSIONS: These findings reveal that over 25% of Pacific Island 2-year-old were affected by OME and recommend the consideration of national screening for OME and other otological disorders at this earlier age.

Child, Preschool↗
PubMed2006

Comparison of biopsy-based methods for the detection of Helicobacter pylori infection.

Various biopsy-based methods for the detection of Helicobacter pylori are evaluated to determine their sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV), followed by polymerase chain reaction (PCR) for the 16S ribosomal RNA (rRNA) gene of H. pylori (16S PCR) to confirm the results. Seventyfive patients (65% [49] males, age range: 17-77 years, mean 42+/-14.6 years) with dyspeptic symptoms are included in the study. Gastric antrum biopsy specimens collected during endoscopy are tested using a urea agar base enriched with 40% urea solution (eUAB, Oxoid)), a commercial rapid urease test (Pronto Dry, Medical Instrument Corp, Switzerland), histopathology and 16S PCR. The eUAB test showed 97% sensitivity, 86% specificity, 84% PPV, 97% NPV and 91% accuracy when the diagnosis of H. pylori infection was made with positive Pronto Dry and histopathology. Pronto Dry showed 100% sensitivity, 82% specificity, 80% PPV, 100% NPV and 89% accuracy when the diagnosis of H. pylori infection was made on positive histopathology and eUAB. Thus, the eUAB can be used as a rapid urease test. It is economical and has a sensitivity and specificity comparable to a commercially available rapid urease test to detect urease activity of H. pylori in gastric biopsy.

Costs and Cost Analysis↗
PubMed2004

Distribution of radium in oil and gas industry wastes from Malaysia.

Radium concentrations in 470 samples of the various types of waste from oil and gas industries were analysed using gamma spectrometers. The results showed that the radium concentration varied within a wide range. The highest mean 226Ra and 228Ra concentrations of 114,300 and 130,120 Bq/kg, respectively, were measured in scales. Overall, 75% of the waste, mostly sludge and extraction residue lies within the normal range of radium concentration in soils of Malaysia. However, some platform sludge can have radium concentration up to 560 Bq/kg.

Industrial Waste↗
PubMed2004

Antinociceptive effect of Melastoma malabathricum ethanolic extract in mice.

The antinociceptive effect of the ethanolic extract of Melastoma malabathricum (MME) was investigated using acetic acid-induced abdominal writhing test and hot-plate test in mice. It was demonstrated that the extract (30-300 mg/kg, i.p.) strongly and dose-dependently inhibited the acetic acid-induced writhing with an ED(50) of 100 (78-160) mg/kg i.p. It also significantly increased the response latency period to thermal stimuli. Furthermore, the nonselective opioid receptor antagonist, naloxone blocked the antinociceptive effect of the extract in both tests, suggesting that M. malabathricum may act both at peripheral and central levels.

Acetic Acid↗
PubMed2004

Familial syndromic duodenal atresia: Feingold syndrome.

Familial duodenal atresia occurs as part of Feingold syndrome. Other features of this variable autosomal dominant condition include tracheo-oesophageal fistula and oesophageal atresia, microcephaly, hand and foot anomalies, facial dysmorphism, and developmental delay. We report a father and two sons with Feingold syndrome. One has bilateral dysplastic kidneys which have not been reported previously.

Abnormalities, Multiple↗
PubMed2003

Auditory comprehension of language in young children: neural networks identified with fMRI.

OBJECTIVE: The organization of neuronal systems that process language in young children is poorly understood. The authors used fMRI to identify brain regions underlying auditory comprehension in healthy young children. METHODS: Fifteen right-handed children (mean age 6.8 years) underwent fMRI at 1.5-T using blood oxygen level dependent echoplanar imaging. They listened to stories with a reverse speech control condition. Group data were analyzed with statistical parametric mapping. Individual subject data were analyzed with a region of interest approach based on t-maps. An asymmetry index (AI = [(L-R)/(L+R)]) was calculated for each region. RESULTS: Group analysis showed significant activation in the left middle temporal gyrus (Brodmann area [BA] 21) and left superior temporal gyrus (BA 22) along the superior temporal sulcus extending back to the angular gyrus (BA 39). Individual maps showed lateralized activation in temporal regions (AI > 0.49 +/- 0.39). There was minimal activation in the frontal lobe. There were no significant correlations between age and regional AI. CONCLUSION: Networks for auditory language processing are regionally localized and lateralized by age 5. These data may provide a means to interpret language fMRI studies performed in preparation for brain surgery, and may be employed to investigate the effect of chronic disease states, such as epilepsy, on language organization during critical periods for plasticity.

Auditory Pathways↗
PubMed2003

Sephadex and sephadex ion-exchange filtration improves the quality and freezability of low-grade buffalo semen ejaculates.

The effect of sephadex and sephadex ion-exchange filtration on the improvement in quality and freezability of low-grade buffalo semen ejaculates was assessed. Two types of filtration columns were used: one containing only sephadex G-10 (FS) and the other sephadex G-10 along with ion-exchangers (diethyl amino ethane-52 (DEAE-52) cellulose and carboxy methyl-52 (CM-52) cellulose; FS+IE). Unfiltered samples served as controls. Semen ejaculates extended in Tris-citric acid (1:4) (n=16; initial motility 40-50%) were filtered at the rate of 1.5 ml/min under negative pressure at room temperature (28-30 degrees C). The mean recovery rate (%) of motile spermatozoa in the FS (85.9+/-1.51) and FS+IE (77.10+/-2.28) filtrates did not differ significantly. Percentages of sperm motility, normal acrosomes, and intact plasma membranes were highest (P<0.05) in FS+IE, intermediate (P<0.05) in FS and lowest (P<0.05) in controls at the three stages of cryopreservation (postfiltration final dilution, after equilibration, and after freezing). Mean sperm abnormalities were lowest (P<0.05) in the filtrates of FS+IE, moderate (P<0.05) in FS and highest in controls at all stages of freezing. Compared to dilution and equilibration, freezing greatly reduced (P<0.05) the overall percent motility, normal acrosomes and intact plasma membranes. The spermatozoa eluted through FS+IE columns proved more resistant (P<0.05) in bearing dilution, equilibration, freezing and thawing stresses than the spermatozoa from FS and control samples. It is concluded that filtration systems containing an FS+IE column can effectively enhance the quality and freezability of extended, low quality buffalo semen.

Acrosome↗
PubMed2003

Electrogustometry: strengths, weaknesses, and clinical evidence of stimulus boundaries.

Electrogustometry is well established as a clinical tool for the estimation of taste detection thresholds. Nevertheless, the user is sometimes unaware of the impact of superficially minor procedural and psychophysical factors upon the reliability and comparability of threshold estimates. The inherent strengths and limitations of the procedure are outlined, and aspects of the control and specification of the stimulus that moderate threshold measures are discussed. In addition, threshold estimates from two individuals with severe unilateral taste loss are used to illustrate the level at which anodal dc current may elicit common, rather than taste, sensation. Where chorda tympani section is complete and historical (older than 7-14 days), very high stimulus levels, conservatively over 5 micro A/mm2 (100 micro A linear current with a 5-mm diameter electrode), are required to activate trigeminal responses.

Adult↗
PubMed2003

Spectrum of cutaneous appendage tumors at Aga Khan University Hospital.

OBJECTIVE: To determine the frequency of various types of cutaneous appendage tumors in our practice. METHOD: This is a partly retrospective and partly prospective study conducted at the Department of Pathology, Histopathology Section, The Aga Khan University Hospital, Karachi between 1st January 1997 and 31st December 2001. RESULTS: One hundred sixty six skin appendage tumors were diagnosed during the study period. 87.3% were benign, while 12.6% were malignant. Male female ratio was almost equal. Mean age was 41.72 years. 37.34% showed eccrine differentiation, 14.45% showed apocrine differentiation and 41.56% showed pilosebaceous differentiation, 6.62% exhibited mixed differentiation. The 5 commonest tumors were pilomatricoma, nodular hidradenoma (eccrine acrospiroma), syringocystadenoma papilleferum, eccrine poroma and eccrine spiradenoma. The commonest malignant tumors were porocarcinoma and sebaceous carcinoma. Pilomatricoma were common in children. CONCLUSION: Most of our findings roughly correlate with the western published data. However, commonest site for eccrine poromas in our study was head and neck. Also, not a single case of eccrine spiradenoma was seen in the first two decades of life. These findings differ significantly from western data.

Adolescent↗
PubMed2001

Large-scale analysis of the Alu Ya5 and Yb8 subfamilies and their contribution to human genomic diversity.

We have utilized computational biology to screen GenBank for the presence of recently integrated Ya5 and Yb8 Alu family members. Our analysis identified 2640 Ya5 Alu family members and 1852 Yb8 Alu family members from the draft sequence of the human genome. We selected a set of 475 of these elements for detailed analyses. Analysis of the DNA sequences from the individual Alu elements revealed a low level of random mutations within both subfamilies consistent with the recent origin of these elements within the human genome. Polymerase chain reaction assays were used to determine the phylogenetic distribution and human genomic variation associated with each Alu repeat. Over 99 % of the Ya5 and Yb8 Alu family members were restricted to the human genome and absent from orthologous positions within the genomes of several non-human primates, confirming the recent origin of these Alu subfamilies in the human genome. Approximately 1 % of the analyzed Ya5 and Yb8 Alu family members had integrated into previously undefined repeated regions of the human genome. Analysis of mosaic Yb8 elements suggests gene conversion played an important role in generating sequence diversity among these elements. Of the 475 evaluated elements, a total of 106 of the Ya5 and Yb8 Alu family members were polymorphic for insertion presence/absence within the genomes of a diverse array of human populations. The newly identified Alu insertion polymorphisms will be useful tools for the study of human genomic diversity.

Alu Elements↗
PubMed2001

Adenoviral vector demonstrates that angiotensin II-induced depression of the cardiac baroreflex is mediated by endothelial nitric oxide synthase in the nucleus tractus solitarii of the rat.

Angiotensin II (ANGII) acting on ANGII type 1 (AT1) receptors in the solitary tract nucleus (NTS) depresses the baroreflex. Since ANGII stimulates the release of nitric oxide (NO), we tested whether the ANGII-mediated depression of the baroreflex in the NTS depended on NO release. In a working heart-brainstem preparation (WHBP) of rat NTS microinjection of either ANGII (500 fmol) or a NO donor (diethylamine nonoate, 500 pmol) both depressed baroreflex gain by -56 and -67 %, respectively (P < 0.01). In contrast, whilst ANGII potentiated the peripheral chemoreflex, the NO donor was without effect. NTS microinjection of non-selective NO synthase (NOS) inhibitors (L-NAME; 50 pmol) or (L-NMMA; 200 pmol) prevented the ANGII-induced baroreflex attenuation (P > 0.1). In contrast, a neurone-specific NOS inhibitor, TRIM (50 pmol), was without effect. Using an adenoviral vector, a dominant negative mutant of endothelial NOS (TeNOS) was expressed bilaterally in the NTS. Expression of TeNOS affected neither baseline cardiovascular parameters nor baroreflex sensitivity. However, ANGII microinjected into the transfected region failed to affect the baroreflex.Immunostaining revealed that eNOS-positive neurones were more numerous than those labelled for AT1 receptors. Neurones double labelled for both AT1 receptors and eNOS comprised 23 +/- 5.4 % of the eNOS-positive cells and 57 +/- 9.2 % of the AT1 receptor-positive cells. Endothelial cells were also double labelled for eNOS and AT1 receptors. We suggest that ANGII activates eNOS located in either neurones and/or endothelial cells to release NO, which acts selectively to depress the baroreflex.

Adenoviridae↗
PubMed2001

Role of Arg-166 in yeast cytochrome C1.

A systematic screen for dominant-negative mutations of the CYT1 gene, which encodes cytochrome c(1), revealed seven mutants after testing approximately 10(4) Saccharomyces cerevisiae strains transformed with a library of mutagenized multicopy plasmids. DNA sequence analysis revealed multiple nucleotide substitutions with six of the seven altered Cyt1p having a common R166G replacement, either by itself or accompanied with other amino acid replacements. A single R166G replacement produced by site-directed mutagenesis demonstrated that this change produced a nearly nonfunctional cytochrome c(1), with diminished growth on glycerol medium and diminished respiration but with the normal or near normal level of cytochrome c(1) having an attached heme group. In contrast, R166K, R166M, or R166L replacements resulted in normal or near normal function. Arg-166 is conserved in all cytochromes c(1) and lies on the surface of Cyt1p in close proximity to the heme group but does not seem to interact directly with any of the physiological partners of the cytochrome bc(1) complex. Thus, the large size of the side chain at position 166 is critical for the function of cytochrome c(1) but not for its assembly in the cytochrome bc(1) complex.

Amino Acid Sequence↗
PubMed2001

Triterpenes from Mimusops elengi.

Pentacyclic triterpenes (1) and (2) have been isolated from Mimusops elengi and assigned structures 3beta,6beta,19alpha,23-tetrahydroxy-urs-12-ene and 1beta-hydroxy-3beta-hexanoyllup-20 (29)-ene-23, 28-dioic acid, respectively, on the basis of spectroscopic studies including 2D-NMR. The compound 1 showed moderate inhibiting activity against beta-glucuronidase enzyme

Animals↗
PubMed2001

Factors related to smoking habits of male secondary school teachers.

A cross-sectional study was conducted to identify the factors related to smoking habits of secondary school teachers in Kelantan, Malaysia. A total of 180 male teachers and trainee teachers from four secondary schools in Kelantan and a Teachers' Training College were interviewed by using a structured questionnaire. Cluster sampling was applied. The significant findings found were current smokers were found as high as 40.56%. Mean duration of smoking was 6.8 years and mean initiation age was 16.5 years. Trainee teachers had a significantly higher proportion of current smokers. There was a significant association between smoking status of teachers and their fathers' and perception of the hazards of smoking on health. Peer influence was found to be the major reason for smoking among smokers. Religious belief and care for health attitude prevented non-smokers from smoking. About 3/5 of smokers thought of quitting smoking and of these 1/4 had tried at least once. There was a significant difference of proportion of attempted quitting between regular and occasional smokers. Mass media was the best source of information on knowledge about smoking hazards. Anti-smoking campaigns should start as early as possible in schools. Lectures and talks on smoking should be included in the curriculum of teachers' training courses.

Cross-Sectional Studies↗
PubMed2000

Histological pattern of ovarian neoplasma.

OBJECTIVE: To see the morphological pattern of benign and malignant ovarian neoplasms. METHOD: Retrospective study of all consecutive cases of ovarian neoplasms diagnosed at Aga Khan University Hospital between 1st January 1993 and 30th September 1998. SETTING: The Section of Histopathology, AKUH, Karachi. OBSERVATION: Of 855 ovarian tumours 506 (59.18%) were benign and 349 (40.81%) malignant. Surface epithelial-stromal tumours comprised 63.50% of all tumours. Benign cystic teratoma was the commonest benign tumour (35.17% of all benign tumours) and serous cystadenocarcinoma was the commonest malignant tumour (33.33% of all malignant tumours). Mucinous cystadenocarcinomas are more common in our population as compared to the West and borderline and malignant mucinous tumours occur at a younger age group. Malignant germ cell tumours are also common in our population. CONCLUSION: Except for the greater frequency of malignant mucinous and germ cell tumours, the findings of our series correspond to the published Western data.

Adolescent↗
PubMed2000

Serological response to immunization with tetanus toxoid.

A total of two hundred women were immunized with tetanus toxoid vaccine. Two batches of toxoid prepared at the Institute of Public Health (IPH), Dhaka and one batch of imported vaccines, were being used by the EPI in Bangladesh for immunization. Each hundred women were immunized by IPH and imported vaccine. Two human doses were given in one month interval. Blood samples from all the study subjects were collected on the day of 1st dose and one month after second dose. Both the preimmunized sera and the sera after vaccination were tested to determine the antibody titre against tetanus toxoid by the haemagglutination method. The preimmunized sera showed the presence of protective antibody in 50(25%) subjects who had the history of previous immunization. Including these initial antitoxin positive cases the seroconversions found among 95% and 96% of the study population respectively after immunization with IPH and imported toxoids, which were 93.05% and 94.87% when these 50 subjects were excluded. No significant difference (p = 1.0) was observed between the immunity of the subjects after receiving IPH and imported vaccine. Antibody titre of initial tetanus-antitoxin positive cases raised eight folds after getting more doses. The result gave fair indication of the antigenicity of all the toxoids used in the study.

Antigens, Bacterial↗