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Biomedical subjects

S Rehman

Publications and source records attributed to S Rehman.

At least 19 recordsLinked to original sources
PubMed2006

Developmental regulation of K accumulation in pollen, anthers, and papillae: are anther dehiscence, papillae hydration, and pollen swelling leading to pollination and fertilization in barley (Hordeum vulgare L.) regulated by changes in K concentration?

The presence of potassium (K) in pollen, anthers and papillae from barley (Hordeum vulgare L.) flowers with different levels of developmental stages starting from boot stage to fully mature flower, was studied by using the K-sensitive fluorescent dye PBFI (potassium-binding benzofuran isophthalate) and confocal laser scanning microscopy. The presence of heavy K fluorescence was detected only at the aperture area of the mature pollen. Similarly, the presence of K increased with the progression from immature to mature anther and papillae. In addition, a higher concentration of K was observed only at the stomium area (the place of anther dehiscence) of mature anthers. Keeping in view the role of K as an active osmoticum and the consistent and synchronized appearance of K in mature pollen, anthers, and papillae, it was concluded that K may regulate anther dehiscence, pollen imbibition, and papillae hydration leading to pollination and fertilization.

Flowers↗
PubMed2006

Radon awareness survey in Pakistan.

Significant progress has been made in reducing the risk from exposure to radon and its progeny all over the world as a result of efforts made by different organisations which are working together to educate public about the harmful effects of radon. During the past several surveys, it was found that uneducated people were totally ignorant of radon in Pakistan. Even a large number of science graduates knew very little about radon and its hazards. Therefore, a nationwide survey was conducted to measure general awareness and factual knowledge about radon and its health hazards. In this regard, a questionnaire was prepared and distributed among different classes of the society including students, government employees and general public throughout the country. A total of 7000 people with different educational backgrounds participated in this survey, which includes uneducated people (1000), science and humanities graduates (2000 each) and under graduate (2000). Statistical analysis, excluding uneducated people, revealed that 30.4% of the total respondents were aware of radon and 69.6% had even not heard of radon. Only approximately 8.4% of the total respondents were knowledgeably aware of radon.

Air Pollutants, Radioactive↗
PubMed2006

Knowledge, attitudes and practices regarding sexually transmitted infections among general practitioners and medical specialists in Karachi, Pakistan.

OBJECTIVES: To determine the knowledge, attitudes and practices regarding diagnosis and treatment of sexually transmitted infections (STIs) among specialists that is, dermatologist, gynecologists and urologists and general practitioners (GPs) in Karachi, Pakistan. METHODS: Interviewers administered structured questionnaires to doctors conducting outpatient clinics at tertiary hospitals and/or private clinics in Karachi. All private clinics within a 10 km radius of the Aga Khan University and all tertiary hospitals having more than 100 inpatient beds were included in the study. RESULTS: One hundred doctors (54 specialists and 46 GPs) responded. Eighty doctors reported seeing at least one STI patient/month. The most commonly diagnosed STI the doctors reported was urethritis/cervicitis syndrome. 50% of the doctors knew the recommended antibiotics for gonorrhea though only 46% of these knew the correct dosage. Specialists were three times more likely to recognize the clinical presentation of herpes and twice as likely to treat chlamydia, syphilis and herpes with appropriate antimicrobials than GPs. 85% of the doctors advised their STI patients regarding condom usage; 36% thought that STI patients had loose sexual morals, 43% believed STI patients were drug addicts. Over 90% of the physicians were willing to attend educational sessions and follow a national STI treatment protocol. CONCLUSION: Doctors in Karachi, especially GPs, are deficient in appropriately managing and counseling STI patients. Among the specialists, urologists and dermatologists were more likely to manage STIs correctly than gynecologists. Karachi doctors should be educated in the correct management and counseling of STIs to prevent further spread of STIs including AIDS (Sex Transm Inf 2000;76:383-85).

Journal Article↗
PubMed2005

Discovery of new etchants for CR-39 detector.

After reporting the excellent etching properties of molten Ba(OH)2 8H2O as an etchant, we now report some more new and efficient etchants for CR-39 detector. CR-39 detectors were irradiated with fission fragments and alpha particles with a thin 252Cf source. The irradiated detectors were etched in a number of our newly introduced etching solutions as well as in conventionally used 6 M NaOH at 70 degrees C. The newly prepared etching solutions included NaOH/ethanol and NaOH/1-propanol. Processing conditions were optimized for these etchants. From fission and alpha track diameters, bulk etching velocity (VB), track etching velocity (VT), etching efficiency (eta) and their activation energies were determined and compared with that obtained for 6M NaOH at 70 degrees C.

1-Propanol↗
PubMed2005

Some more new etchants for CR-39 detector.

Recently, several new etchants have been reported for CR-39 detector (Molten Ba(OH)2. 8H2O as an etchant for CR-39 detector, Radiat. Meas. 37 (2003) 205; Discovery of new etchants for CR-39 detector, Radiat. Meas. (2004)). We have made further progress in this direction and have unveiled two more new etchants which are reported in this article. CR-39 detectors were irradiated with fission fragments and alpha particles from a thin 252Cf disc source. The irradiated detectors were then etched in our newly introduced etching solutions as well as in conventionally used 6 M NaOH aqueous solution at 70 degrees C. The newly prepared etching solutions included NaOH dissolved in methanol and NaOH dissolved in methanol + water. Optimum values of NaOH concentration in methanol as well as in methanol + water were determined. Optimum etching temperatures were also determined for both the above-mentioned etchants. From fission and alpha track diameters, bulk etching rate (VB), track etching rate (VT) and etching efficiency (eta) were determined and compared with that obtained for 6 M NaOH at 70 degrees C. Both the newly introduced etchants were found more efficient than the conventionally used 6 M aqueous NaOH (64%) at 70 degrees C and have relatively much smaller etching time.

Alpha Particles↗
PubMed2005

Functional analysis of pathogenicity proteins of the potato cyst nematode Globodera rostochiensis using RNAi.

RNA interference (RNAi) has been used widely as a tool for examining gene function and a method that allows its use with plant-parasitic nematodes recently has been described. Here, we use a modified method to analyze the function of secreted beta-1,4, endoglucanases of the potato cyst nematode Globodera rostochiensis, the first in vivo functional analysis of a pathogenicity protein of a plant-parasitic nematode. Knockout of the beta-1,4, endoglucanases reduced the ability of the nematodes to invade roots. We also use RNAi to show that gr-ams-1, a secreted protein of the main sense organs (the amphids), is essential for host location.

Animals↗
PubMed2003

Indoor radon levels and lung cancer risk estimates in seven cities of the Bahawalpur Division, Pakistan.

Indoor radon concentration levels were measured in seven major cities of the Bahawalpur Division, Pakistan. These included Fort Abbas, Minchin Abad, Hasilpur, Bahawalpur, Liaqatpur, Rahimyar Khan and Sadiq Abad. In order to select houses for this survey, the inhabitants were approached through their school-registered children. Due to several constraints, only those 100 houses were chosen in each city that were relatively the best representatives of the built-up area. The selected houses were then divided into live categories according to the house locations and building characteristics. CR-39 detectors, placed in polyethylene bags. were installed at head height in bedrooms and sitting rooms of all the selected houses and were exposed to radon and its daughter products for 90 days. Four such measurements were performed over a year in order to average out the seasonal variation in radon levels. After exposure, all the detectors were etched and counted under an optical microscope. The track densities of four measurements were averaged out and related to radon concentration levels. The radon levels were found to be 20, 20, 26, 28, 34, 42, 47 Bq m(-3) in the bedrooms and 24, 26, 27, 26, 37, 40, 43 Bq m(-3) in sitting rooms of Hasilpur, Rahimyar Khan, Minchin Abad, Fort Abbas, Sadiq Abad, Bahawalpur and Liaqatpur respectively. The observed variation in the radon level may be attributed to the geological variation in the area. Based on the observed data, excess lung cancer risk was assessed using the risk factors recommended by the USEPA, UNSCEAR and the ICRP. According to the EPA model, the lifetime excess lung cancer risk due to the lifetime exposure is found to vary from 12-102 per million per year in the houses surveyed. This variation is from 16-114 and 26-62 per million per year if UNSCEAR and ICRP limits are applied respectively.

Air Pollutants, Radioactive↗
PubMed2002

HLA polymorphism in six ethnic groups from Pakistan.

The extreme polymorphism found at some of the loci of the HLA system has made it an invaluable tool for population genetic analyses. In this study the genetic polymorphism of six Pakistani ethnic groups was investigated at the HLA-A, -B, -C, -DRB and DQB1 loci using polymerase chain reaction with sequence specific primers. The groups included in this study are the Baloch, Brahui and Sindhi from the south and the Burusho, Kalash and Pathan from the north of Pakistan. The allele frequencies, three-locus haplotype frequencies for HLA-A, -C, -B and HLA-A, -B, -DRB1 are given. Variation in the allele and haplotype distribution between the six Pakistani ethnic groups was observed. A phylogenetic tree and correspondence analysis based on HLA-A, -B, -C, -DRB1 and -DQB1 allele frequencies revealed the Kalash population to be distinct from the remaining Pakistani populations. The Baloch and Brahui were closely related to one another. The Sindhi were closer to the Pathan and Burusho populations than to the neighboring Baloch and Brahui populations, indicating admixture between the northern and southern populations of Pakistan. A phylogenetic tree and correspondence analysis comparing the Pakistani populations with various other world populations showed that the Pakistani ethnic groups lie within the cluster of Asian Indian populations. The three-locus haplotypes found in the Pakistani populations suggest an influence from Caucasian and Oriental populations.

Ethnicity↗
PubMed2001

Tissue specific and inducible expression of resveratrol synthase gene in peanut plants.

The expression of resveratrol synthase (RS) genes is induced by biotic and abiotic factors in peanut cell cultures. However, little is known about the regulation of the RS gene expression in peanut plants. The expression of RS genes was investigated in peanut plants with a peanut RS clone, pPRS3C, which encodes two polypeptides that show about a 96% amino acid sequence identity to peanut RS2 and RS3, respectively. A low level of RS mRNA was detected in the roots of peanut plants grown aseptically in vitro. In mature peanut plants that were grown in the field, however, RS mRNAs were present at relatively high levels in both the roots and pods, but at below the detection limit in leaves. RS mRNAs were abundant in young pods and decreased dramatically in mature pods. The RS mRNA expression was induced by yeast extract and UV in leaves and roots, and also by wounding in leaves. Stress hormones, such as ethylene, jasmonic acid, and salicylic acid, induced RS mRNA accumulation in leaves. These results indicate that the RS gene expression is induced by biotic and abiotic stresses through the stress hormones in peanut plants. The induction of the RS gene expression by biotic and abiotic stresses could provide peanut plants with protection from microbial infections through resveratrol synthesis. The RS gene expression in developing pods has significant implications in terms of the role of resveratrol as a phytochemical for human health.

Acyltransferases↗
PubMed2000

Bax protein expression in DCIS of the breast in relation to invasive ductal carcinoma and other molecular markers.

This study describes the incidence of Bax protein expression in a series of 106 cases of breast cancer including 56 cases of ductal carcinoma in situ (DCIS) and 50 cases of invasive ductal carcinoma (IDC). Relationships of Bax expression to the histological grades of DCIS & IDC, and to the expression of Ki67, ER, p53, cerbB2 & Bcl2 are described. The expression of Bax, Ki67, ER, p53, cerbB2 and Bcl2 proteins is determined immunohistochemically. Cases were regarded positive for Bax, Bcl2 and cerbB2 when they showed either moderate or strong staining for these markers. The nuclear stains (Ki67, ER, and p53) were quantified in terms of percentage positive cells and cases for ER and p53 were considered positive when more than 10% cells were labelled. DCIS were graded histologically as well (n=18), intermediately (n=18), and poorly differentiated (n=20) Invasive ductal carcinoma was graded as grade I (well-differentiated) n=7, grade II (intermediate) n=24 and grade III (poorly differentiated) n=19. 65/106 cases (61%) were Bax positive including 37/56 (66%) of DCIS and 28/50 (56%) of IDC. Bax expression did not correlate to increasing histological grades of either DCIS or IDC. It did not correlate to Ki67, ER, p53 or cerbB2 but positive correlation was seen with Bcl2 (p=0.003). Bcl2 immunostaining displayed a negative correlation with increasing histological grades both of DCIS and IDC (p=0.026), (p=0.041) respectively. There was a trend of negative correlation of Bcl2 with Ki67 (p=0.062). It correlated positively with Bax (p=0.003) and ER (p<0.0001). Results suggest that the regulation of apoptosis is important in ductal carcinoma in situ of the breast as well as invasive ductal carcinomas. Bcl2 is associated with good prognostic markers in both DCIS and IDC, whereas the regulation of Bax is complex and does not necessarily correlate with mutant p53.

Adult↗
PubMed2000

Humeral blade plate fixation of intercalary allografts and segmentally comminuted proximal humeral fractures: a preliminary report.

The AO 90 degrees humeral blade plate is a relatively new device, whose primary indication and previously described use is for proximal humeral fracture non-union. This study describes the use of the humeral blade plate for extended indications-fixation of segmentally comminuted proximal humeral fractures in two patients and fixation of humeral intercalary allografts after primary humeral neoplasm resection in three patients. A mean follow-up of 20 months revealed union in both fractures and five of the six allograft-host junctions. One patient required subsequent bone grafting for non-union at a proximal allograft-host junction. Functional results were excellent in three patients, good in one, and fair in one. Problems encountered intraoperatively were directly related to the limited array of implants. The long plates which were needed had blades which were too long and required intra-operative trimming in three cases. In four cases, additional plates were used to supplement the blade plate for distal fixation. In conclusion, the humeral blade plate is a useful device for fixation in these extended indications, but longer plates with 30.0 and 40.0-mm blade lengths should be made available.

Adult↗
PubMed1997

Complement activation by heparin-protamine complexes during cardiopulmonary bypass: effect of C4A null allele.

OBJECTIVES: The first objective was to determine the effect of inherited differences in the classic pathway complement protein C4 on complement activation by heparin-protamine complexes in cardiac surgery. Specifically, we hypothesized that patients with heterozygous C4A null phenotype (A0BB), who have decreased amounts of C4A, may have increased complement activation because of reduced clearance of heparin-protamine complexes. The second objective was to determine whether heparin-protamine-induced complement activation correlated with postoperative pulmonary shunt fractions. METHODS: C4 typing was performed by agarose gel immunofixation and crossed immunoelectrophoresis. Complement activation was measured by radioimmunoassay of C3a and C4a before cardiopulmonary bypass, after bypass, and after protamine infusion. Shunt fractions were calculated from blood gases. RESULTS: Of the 79 patients, 18 expressed heterozygous C4A null allele (A0BB), 16 had heterozygous C4B null allele (AAB0), three had homozygous C4B null alleles (AA00), and the rest expressed both C4A and C4B alleles (AABB). Patients with heterozygous C4A null allele had significantly increased plasma levels of C4a after protamine neutralization of heparin (C4a of 2862 +/- 375 ng/ml; mean +/- standard error of the mean) when compared with patients with normal expression of C4 alleles (AABB) (C4a of 1580 +/- 141 ng/ml) or heterozygous C4B null allele (C4a 1526 +/- 208 ng/ml). Pulmonary shunt fractions obtained after the operation correlated with the classic pathway complement activation by heparin-protamine complexes, but not with alternative pathway complement activation during cardiopulmonary bypass. CONCLUSIONS: Patients with heterozygous C4A null phenotype have increased complement activation by heparin-protamine complexes during cardiac operations, possibly because of their defective clearance. The classic pathway complement activation by heparin-protamine interaction correlates with postoperative pulmonary shunt fractions.

Alleles↗
PubMed1997

Discharging routine phacoemulsification patients at one week.

The reduction of surgically induced astigmatism and rapid refractive stabilisation after phacoemulsification have been well studied and often lead to reduced follow-up. In this prospective study we reviewed a cohort of 100 patients discharged with a refractive prescription at their 1 week post-operative appointment following routine sutureless phacoemulsification through a corneal or scleral section. The aim was to assess the incidence of late pathology and need for review. Eighty-eight patients attended for review between 3 and 4 months post-operatively, of whom 8 (9.1%) who had been symptomatic had already visited ophthalmic casualty. Nine (10.2%) benefited from the follow-up appointment: 4 were given a new refractive prescription that increased their Snellen visual acuity by 1 line; the other 5 were all symptomatic or had incidental findings. We feel that provided there is easy access to the eye department, early discharge with or without refraction is justifiable as those with surgically related pathology at any stage are symptomatic.

Emergency Service, Hospital↗
PubMed1997

The role of osmotic diuretics in the management of eclampsia in Karachi women.

In the present work, out of eighty (80) patients selected, suffering from eclampsia, thirty-five (35) were subjected to the combined therapy of diazepam (7-Chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1, 4-benzo-diazepin-2-one) and mannitol (Osmotic diuretic) and forty-five (45) patients were administered diazepam only. Consequently it was inferred that osmotic diuretic (mannitol) exhibits beneficial effects on the management of eclampsia, thereby lowering the mortality and morbidity.

Journal Article↗
PubMed1995

Crimean Congo-haemorrhagic fever treated with oral ribavirin.

Crimean-Congo Haemorrhagic Fever (CCHF) is an often-lethal haemorrhagic fever caused by a tick-borne virus. There are no published data on ribavirin treatment of CCHF-infected patients, despite established in-vitro and in-vivo sensitivity. We report three health workers--two surgeons and a hospital worker--infected with CCHF virus in Pakistan who were treated with oral ribavirin 4 g/day for four days, then 2.4 g/day for six days. Intravenous ribavirin was unavailable. All three patients were severely ill with low platelet and white-cell counts, raised aspartate transaminase and evidence of impaired haemostasis. Based on published reports, all had an estimated probability of death of 90% or more. The patients became afebrile, and their haematological and biochemical abnormalities returned to normal within 48 h of ribavirin treatment; all made a complete recovery, and developed IgG and IgM antibody to CCHF virus. Our experience with ribavirin treatment is encouraging, but does not constitute evidence of efficacy. Given the difficulties in gathering adequate treatment data, we propose a consensus protocol for both intravenous and oral treatment of CCHF. This protocol could be distributed to key medical personnel in areas endemic for CCHF and used to provide a firm basis for effective treatment recommendations.

Acute Disease↗
PubMed1995

Evaluation of malondialdehyde as an index of lead damage in rat brain homogenates.

Lipid peroxidation in vitro homogenates of brain was examined as sequela of lead toxicity. The levels of malondialdehyde (MDA) in homogenates of rat brain (1 ml, 5% w/v) treated with lead (50 micrograms) alone or in combination with ascorbic acid (100 micrograms), alphatocopherol (100 micrograms) or hydroquinone (100 micrograms) were evaluated. The levels of MDA were consistently evoked by lead in a dose-related manner. The toxicity of lead was further advanced by the action of the pro-oxidant drug ascorbic acid on the brain. However, the anti-oxidant drugs alphatocopherol and hydroquinone decreased the toxic effect of lead on the brain. These results clearly show that the enhanced lipid peroxidation may provide a basis of lead-induced neurotoxicity.

Animals↗
PubMed1990

Alzheimer cortical neurons containing abundant amyloid mRNA. Relationship to amyloid deposition and senile plaques.

Since the detailed molecular events leading to the formation of amyloid-containing senile plaques of the Alzheimer's disease (AD) brain are incompletely understood, the present studies were undertaken to address this issue using a combination of molecular and cytochemical approaches. Amyloid precursor protein riboprobes containing the A4 (beta-amyloid) domain were applied to cortex using the in situ hybridization method to examine the distribution of neuronal amyloid mRNA in relation to the laminar pattern of amyloid deposition and the localization of plaques. The derived data indicated that high levels of amyloid mRNA can be synthesized by AD cortical neurons that appeared to be morphologically intact. The distribution of these cells was not coincident with the cortical laminar pattern that is typical of amyloid deposits observed after immunostaining with anti-A4 monoclonal antibodies. Further, there was no obvious relationship between neurons containing abundant amyloid mRNA and the distribution of plaques identified by thioflavin S staining. While the neuronal synthesis of amyloid may be a significant factor at some point during plaque formation, it may not be the exclusive determinant. The possibility is raised that processes affecting secretion, diffusion, and/or transport of amyloid away from neuronal or non-neuronal cells of origin to sites of deposition may be meaningful aspects of the molecular pathology of Alzheimer's disease.

Aged↗