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Biomedical subjects

M Ahmad

Publications and source records attributed to M Ahmad.

At least 55 records · Page 3Linked to original sources
PubMed2002

Insecticide-treated plastic tarpaulins for control of malaria vectors in refugee camps.

Spraying of canvas tents with residual pyrethroid insecticide is an established method of malaria vector control in tented refugee camps. In recent years, plastic sheeting (polythene tarpaulins) has replaced canvas as the utilitarian shelter material for displaced populations in complex emergencies. Advances in technology enable polythene sheeting to be impregnated with pyrethroid during manufacture. The efficacy of such material against mosquitoes when erected as shelters under typical refugee camp conditions is unknown. Tests were undertaken with free-flying mosquitoes on entomological study platforms in an Afghan refugee camp to compare the insecticidal efficacy of plastic tarpaulin sprayed with deltamethrin on its inner surface (target dose 30 mg/m2), tarpaulin impregnated with deltamethrin (initially > or = 30 mg/m2) during manufacture, and a tent made from the factory impregnated tarpaulin material. Preliminary tests done in the laboratory with Anopheles stephensi Liston (Diptera: Culicidae) showed that 1-min exposure to factory-impregnated tarpaulins would give 100% mortality even after outdoor weathering in a temperate climate for 12 weeks. Outdoor platform tests with the erected materials (baited with human subjects) produced mosquito mortality rates between 86-100% for sprayed or factory-impregnated tarpaulins and tents (average approximately 40 anophelines and approximately 200 culicines/per platform/night), whereas control mortality (with untreated tarpaulin) was no more than 5%. Fewer than 20% of mosquitoes blood-fed on human subjects under either insecticide-treated or non-treated shelters. The tarpaulin shelter was a poor barrier to host-seeking mosquitoes and treatment with insecticide did not reduce the proportion blood-feeding. Even so, the deployment of insecticide-impregnated tarpaulins in refugee camps, if used by the majority of refugees, has the potential to control malaria by killing high proportions of mosquitoes and so reducing the average life expectancy of vectors (greatly reducing vectorial capacity), rather than by directly protecting refugees from mosquito bites. Mass coverage with deltamethrin-sprayed or impregnated tarpaulins or tents has strong potential for preventing malaria in displaced populations affected by conflict.

Afghanistan↗
PubMed2002

Intravaginal vibrator of long duration.

Intravaginal foreign bodies of long duration are a rare entity and are seen in the practice of Obstetrics and Gynaecology, but patients may present to the Accident and Emergency department for their removal. Various bizarre objects have been inserted into the vagina and many patients are too embarrassed and will wait and try to remove them themselves rather than seek medical advice. Vaginal foreign bodies of long duration may be complicated by fistulas and such patients should be referred to the gynaecologist.

Female↗
PubMed2002

Assessment of genomic diversity among wheat genotypes as determined by simple sequence repeats.

Simple sequence repeats (SSRs) have been used to examine the genomic diversity of wheat (Triticum aestivum L.) germplasm. Thirteen wheat genotypes of diverse origin were analyzed with 43 selected SSRs to provide uniform and maximum genome coverage. A total of 156 allelic variants were detected at 43 SSR loci, ranging from two to eight per locus with an average of 3.6. The polymorphic information content (PIC) values of the loci ranged from 0.10 (Xgwm264) to 0.89 (Xgwm471 and Xgwm577). Genetic similarities calculated from SSR data ranged from 30.1 ('Era' and 'Klasic') to 90.1 ('Neepawa' and 'Thatcher') between genotypes. UPGMA analysis based on genetic distance estimates produced three loose groupings that were generally consistent with available pedigree information. Cultivars 'Neepawa' and 'Thatcher' are closely related. Their genetic relationship was confirmed by the facts that they share a common ancestor and are clustered together. There were two different 'Era' genotypes, one used in the 'Otane' pedigree and one used in this study. None of the other genotypes had a close common ancestor indicating any close genetic relationships. Principal coordinate analysis also confirmed this pattern of genetic diversity. A wide range of genomic diversity was observed among all the genotypes, proving them to be prime candidates for selective breeding for specific traits and broadening the genetic base.

Evolution, Molecular↗
PubMed2002

Norditerpenoid alkaloids from the roots of Aconitum leave Royle.

From the roots of Aconitum leave Royle growing wild in Northern Pakistan, Swat district, three new alkaloids, 8-methyllycaconitine (1), 14-demethyllycaconitine (2), N-deethyllycaconitine-N-aldehyde (3) have been isolated along with four known compounds, lappaconitine (4), lycaconitine (5), lapaconidine (6) and lycoctonine (7).

Alkaloids↗
PubMed2002

An evaluation of cefaclor in Pakistani children with pharyngotonsillitis.

OBJECTIVE: To assess the efficacy, safety of cefaclor for the treatment of pharyngotonsillitis in Pakistani children. METHOD: Pakistani children between the ages of two to twelve years and diagnosed with pharyngotonsillitis were eligible to participate in the study. Cefaclor was administered three times daily for a total dose of 20-40 mg/kg/day, depending on the severity of the infection, for 7 days. Patients were evaluated on the basis of symptomatic response and antibiotic susceptibility pattern as a result of bacteriological examination. RESULTS: Based on observed pre-therapy signs/symptoms of infection with pharyngotonsillitis, 99% of patients (95% CI=94.9% to 100.0%) were reported as having a symptomatic response of Cure or Improvement by end of study. Group A b-haemolytic Streptococci was the most prevalent pathogen isolated pre-therapy (occurring in 45% of patients). Of all patients for whom this pathogen was isolated, 64% had complete eradication by end of therapy, while there was persistence or superinfection in 36% of patients. Only 9 occurrences of non-serious adverse events were observed among 7 of the 107 patients, including diarrhea (5), nausea (1), vomiting (1), rash (1) and stomatitis (1). CONCLUSION: Based on the high symptomatic response rate of 99% and the positive safety data, cefaclor was found to be effective and safe in treating Pakistani children with pharyngotonsillitis.

Anti-Bacterial Agents↗
PubMed2001

Dynamics and post-collision interaction effects in two electron decay from the Xenon 4d hole.

Two Auger electrons, one very slow, one fast, have been detected in coincidence following near threshold 4d photoionization of the Xe atom. The distribution in the energy the two electrons share has been measured for the first time revealing the presence of post-collision interaction effects that provide unique information on the decay dynamics of the 4d hole. Analysis of the distorted line shapes indicates that the dominant process is decay of Xe+(4d(-1)) to Xe3+ through cascade emission of a zero kinetic energy Auger electron followed by a fast Auger electron. The widths of the intermediate Xe2+* states are estimated to be about 60 meV.

Journal Article↗
PubMed2001

Three-dimensional radiotherapy of head and neck and esophageal carcinomas: a monoisocentric treatment technique to achieve improved dose distributions.

The specific aim of three-dimensional conformal radiotherapy is to deliver adequate therapeutic radiation dose to the target volume while concomitantly keeping the dose to surrounding and intervening normal tissues to a minimum. The objective of this study is to examine dose distributions produced by various radiotherapy techniques used in managing head and neck tumors when the upper part of the esophagus is also involved. Treatment planning was performed with a three-dimensional (3-D) treatment planning system. Computerized tomographic (CT) scans used by this system to generate isodose distributions and dose-volume histograms were obtained directly from the CT scanner, which is connected via ethernet cabling to the 3-D planning system. These are useful clinical tools for evaluating the dose distribution to the treatment volume, clinical target volume, gross tumor volume, and certain critical organs. Using 6 and 18 MV photon beams, different configurations of standard treatment techniques for head and neck and esophageal carcinoma were studied and the resulting dose distributions were analyzed. Film validation dosimetry in solid-water phantom was performed to assess the magnitude of dose inhomogeneity at the field junction. Real-time dose measurements on patients using diode dosimetry were made and compared with computed dose values. With regard to minimizing radiation dose to surrounding structures (i.e., lung, spinal cord, etc.), the monoisocentric technique gave the best isodose distributions in terms of dose uniformity. The mini-mantle anterior-posterior/posterior-anterior (AP/PA) technique produced grossly non-uniform dose distribution with excessive hot spots. The dose measured on the patient during the treatment agrees to within +/- 5 % with the computed dose. The protocols presented in this work for simulation, immobilization and treatment planning of patients with head and neck and esophageal tumors provide the optimum dose distributions in the target volume with reduced irradiation of surrounding non-target tissues, and can be routinely implemented in a radiation oncology department. The presence of a real-time dose-measuring system plays an important role in verifying the actual delivery of radiation dose.

Carcinoma↗
PubMed2001

Preemptive analgesia I: physiological pathways and pharmacological modalities.

PURPOSE: This two-part review summarizes the current knowledge of physiological mechanisms, pharmacological modalities and controversial issues surrounding preemptive analgesia. SOURCE: Articles from 1966 to present were obtained from the MEDLINE databases. Search terms included: analgesia, preemptive; neurotransmitters; pain, postoperative; hyperalgesia; sensitization, central nervous system; pathways, nociception; anesthetic techniques; analgesics, agents. PRINCIPAL FINDINGS: The physiological basis of preemptive analgesia is complex and involves modification of the pain pathways. The pharmacological modalities available may modify the physiological responses at various levels. Effective preemptive analgesic techniques require multi-modal interception of nociceptive input, increasing threshold for nociception, and blocking or decreasing nociceptor receptor activation. Although the literature is controversial regarding the effectiveness of preemptive analgesia, some general recommendations can be helpful in guiding clinical care. Regional anesthesia induced prior to surgical trauma and continued well into the postoperative period is effective in attenuating peripheral and central sensitization. Pharmacologic agents such as NSAIDs (non-steroidal anti-inflammatory drugs) opioids, and NMDA (N-methyl-D-aspartate) - and alpha-2-receptor antagonists, especially when used in combination, act synergistically to decrease postoperative pain. CONCLUSION: The variable patient characteristics and timing of preemptive analgesia in relation to surgical noxious input requires individualization of the technique(s) chosen. Multi-modal analgesic techniques appear most effective.

Adrenergic alpha-Antagonists↗
PubMed2001

Preemptive analgesia II: recent advances and current trends.

PURPOSE: This two-part review summarizes the current knowledge of physiological mechanisms, pharmacological modalities and controversial issues surrounding preemptive analgesia. SOURCE: Articles from 1966 to present were obtained from the MEDLINE databases. Search terms included analgesia, preemptive; neurotransmitters; pain, postoperative; hyperalgesia; sensitization, central nervous system; pathways, nociception; anesthetic techniques; analgesics, agents. PRINCIPAL FINDINGS: In Part I of this review article, techniques and agents that attenuate or prevent central and peripheral sensitization were reviewed. In Part II, the conditions required for effective preemptive techniques are evaluated. Specifically, preemptive analgesia may be defined as an antinociceptive treatment that prevents establishment of altered central processing of afferent input from sites of injury. The most important conditions for establishment of effective preemptive analgesia are the establishment of an effective level of antinociception before injury, and the continuation of this effective analgesic level well into the post-injury period to prevent central sensitization during the inflammatory phase. Although single-agent therapy may attenuate the central nociceptive processing, multi-modal therapy is more effective, and may be associated with fewer side effects compared with the high-dose, single-agent therapy. CONCLUSION: The variable patient characteristics and timing of preemptive analgesia in relation to surgical noxious input require individualization of the technique(s) chosen. Multi-modal analgesic techniques appear more effective.

Analgesics, Opioid↗
PubMed2001

Occurrence of the vanA and vanC2/C3 genes in Enterococcus species isolated from poultry sources in Malaysia.

Enterococcus species isolated from poultry sources were characterized for their resistance to antibiotics, plasmid content, presence of van genes and their diversity by randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR). The results showed that all isolates were multi-resistance to the antibiotics tested. Ampicillin (15/70) followed by chloramphenicol (37/70) were the most active antibiotics tested against the Enterococcus spp. isolates, while the overall resistant rates against the other antibiotics were between 64.3% to 100%. All vancomycin-resistant E. faecalis, E. durans, E. hirae and E. faecium isolates tested by the disk diffusion assay were positive in PCR detection for presence of vanA gene. All E. casseliflavus isolates were positive for vanC2/C3 gene. However, none of the Enterococcus spp. isolates were positive for vanB and vanC1 genes. Plasmids ranging in sizes between 1.1 to ca. 35.8 MDa were detected in 38/70 of the Enterococcus isolates. When the genetic relationship among all isolates of the individual species were tested by RAPD-PCR, genetic differences detected suggested a high genetic polymorphisms of isolates in each individual species. Our results indicates that further epidemiological studies are necessary to elucidate the role of food animals as reservoir of VRE and the public health significance of infections caused by Enterococcus spp.

Animals↗
PubMed2001

Real-time three-dimensional dobutamine stress echocardiography in assessment stress echocardiography in assessment of ischemia: comparison with two-dimensional dobutamine stress echocardiography.

OBJECTIVES: This study was designed to test the feasibility and efficacy of using real-time three-dimensional echocardiography (RT-3D) to detect ischemia during dobutamine-induced stress (DSE) and compares the results with conventional two-dimensional echocardiography (2D). BACKGROUND: Real-time three-dimensional echocardiography, a novel imaging technique, offers rapid acquisition with multiple simultaneous views of the left ventricle (LV). These features make it attractive for application during stress. METHODS: Of 279 consecutive patients screened for image quality by 2D, 253 patients with adequate images underwent RT-3D and 2D within 30 s of each other at baseline and at peak DSE. RESULTS: Real-time three-dimensional echocardiography and 2D showed good concordance in detection of abnormal LV wall motion at baseline (84%: Kappa = 0.59) and at peak DSE (88.9%: Kappa = 0.72). Left ventricular wall motion scores were similar at baseline and peak DSE using both techniques. Interobserver agreements for detection of ischemia at peak DSE were superior for RT-3D, 92.7% compared with 84.6% for 2D (p < 0.05). Mean scanning time at peak stress by RT-3D in 50 randomly selected patients was shorter, 27.4 +/- 10.7 s compared with 62.4 +/- 20.1 s by 2D (p < 0.0001). In 90 patients with coronary angiograms, RT-3D had a sensitivity of 87.9% in the detection of coronary artery disease (CAD) compared with 79.3% by 2D. CONCLUSIONS: Real-time three-dimensional dobutamine stress echocardiography is feasible and sensitive in the detection of CAD. The procedure offers shorter scanning time, superior interobserver agreements and unique new views of the LV.

Coronary Disease↗
PubMed2001

Origin and subsurface history of geothermal water of Murtazabad area, Pakistan--an isotopic evidence.

The Murtazabad area represents one of the major geothermal fields in Pakistan, with seven hot springs lying along the Main Karakoram Thrust. Discharge of the springs is 50-1200 l per minute with the surface temperature from 40 to 94 degrees C. Environmental isotopes and chemical concentrations have been used to investigate the origin and subsurface history of thermal water. Four sets of water samples were collected and analyzed for various isotopes including 18O, 2H and 3H of water; 34S and 18O of dissolved sulphates and chemical contents. Isotopic and chemical data show that the origin of thermal water is meteoric water. On the delta-diagram, delta18O and delta2H data plotting below the local meteoric water line with a slope around 12.3 show that the original thermal water receives recharge from precipitation at higher altitude (3000 m) and undergoes delta18O shift of about 1 per thousand due to exchange with rocks. Different correlations between isotopes, temperature and Cl indicate that the observed isotopic compositions have evolved due to mixing of different proportions of shallow water at different spring paths during movement of thermal water towards the surface. It is also inferred from the tritium data along with delta18O and delta2H that the circulation time is long and is estimated to be more than 50 years.

Journal Article↗
PubMed2001

Revised structures for senegalensin and euchrenone b(10).

Two prenylated isoflavones (1 and 2) with a hydroxyisopropyldihydrofuran moiety have been isolated from the wood of Erythrina suberosa var. glabrescence. The structure of compound 1 was in agreement with that of the previously reported senegalensin, isolated from the stem bark of Erythrina senegalensis. The structure of senegalensin was revised from structure 2 to structure 1 by spectroscopic means. Compound 2, the regioisomer of 1, was confirmed as euchrenone b(10) by comparison with the spectral data of the reported euchrenone b(10), isolated from the roots of Euchresta horsfieldii. The structure of 2 was established by 2D NMR spectroscopic analysis and by the X-ray crystallographic analysis of its p-bromobenzoyl derivative (2b).

Chromatography, Gel↗
PubMed2001

Regulation of IL-1beta generation by Pseudo-ICE and ICEBERG, two dominant negative caspase recruitment domain proteins.

We report here the identification and functional characterization of two new human caspase recruitment domain (CARD) molecules, termed Pseudo-interleukin-1beta converting enzyme (ICE) and ICEBERG. Both proteins share a high degree of homology, reaching 92% and 53% identity, respectively, to the prodomain of caspase-1/ICE. Interestingly, both Pseudo-ICE and ICEBERG are mapped to chromosome 11q22 that bears caspases-1, -4- and -5 genes, all involved in cytokine production rather than in apoptosis. We demonstrate that Pseudo-ICE and ICEBERG interact physically with caspase-1 and block, in a monocytic cell line, the interferon-gamma and lipopolysaccharide-induced secretion of interleukin-1beta which is a well-known consequence of caspase-1 activation. Moreover, Pseudo-ICE, but not ICEBERG, interacts with the CARD-containing kinase RICK/RIP2/CARDIAK and activates NF-kappaB. Our data suggest that Pseudo-ICE and ICEBERG are intracellular regulators of caspase-1 activation and could play a role in the regulation of IL-1beta secretion and NF-kappaB activation during the pro-inflammatory cytokine response.

Amino Acid Sequence↗
PubMed2001

Real-time three-dimensional echocardiography in assessment of heart disease.

Echocardiography has progressed at an impressive pace in the last decade. A plethora of new techniques, including tissue-Doppler imaging, harmonic imaging, contrast echocardiography, digital-stress echocardiography, and three-dimensional (3-D) echocardiography, have altered our diagnostic strategies for managing patients with heart disease. Until recently, 3-D echocardiography was looked upon as a time-consuming and tedious procedure, making it more a research interest than a diagnostic tool. The introduction of real-time three-dimensional (RT-3-D) echocardiography has made possible dynamic diagnostic/therapeutic assessments while the procedure is performed. At The University of Texas Medical Branch in Galveston, Texas, our more than 2 years of experience with RT-3-D suggests that this technique will play an important role in diagnosing and managing patients with heart disease.

Echocardiography, Three-Dimensional↗