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Biomedical subjects

M Ahmad

Publications and source records attributed to M Ahmad.

At least 181 records · Page 10Linked to original sources
PubMed1997

The effect of sepsis on breathing pattern and weaning outcomes in patients recovering from respiratory failure.

OBJECTIVE: To determine the effects of sepsis on breathing pattern and weaning outcome in medical patients recovering from respiratory failure. DESIGN: Prospective, observational study. SETTING: Medical ICU of a 300-bed community teaching hospital. MEASUREMENTS: Patients were classified as having sepsis or not having sepsis on the first day of weaning. The respiratory rate:tidal volume ratio (RVR), maximal inspiratory pressure (MIP), respiratory system mechanics, minute volume, WBC count, and maximal temperature (Tmax) were recorded for the first day of weaning. Weaning was then conducted by the patients' primary physicians; weaning outcomes and days spent receiving mechanical ventilation were recorded. RESULTS: Sixty patients were studied over 64 separate ICU admissions. Twenty-five patients met criteria for sepsis and had a higher mean APACHE II (acute physiology and chronic health evaluation) score than patients without sepsis (mean+/-SE: 23.4+/-1.3 vs 18.7+/-1.0; p<0.05). Respiratory mechanics, age, and minute volumes were not different between patients with and without sepsis. Patients with sepsis had a higher RVR than patients without sepsis (94.3+/-10.1 vs 66.6+/-6.4 breaths/min/L; p<0.05) and tended to have a lower MIP (25.0+/-2.0 vs 31.0+/-2.3 cm H2O; p=0.055). The MIP and RVR were moderately correlated (r=0.50, p<0.001). WBC count and Tmax did not correlate with RVR in the total population or in sepsis/nonsepsis subpopulations. First-day weaning success was higher in patients without sepsis (17/39=44%) than patients with sepsis (6/25=24%; odds ratio=2.4; 95% confidence interval=0.8 to 7.3). Patients with sepsis tended to require a longer duration of weaning (3.8+/-0.6 vs 2.5+/-0.5 days; p=0.1) and mechanical ventilation (7.4+/-1.0 vs 5.6+/-1.0 days; p=0.2) than patients without sepsis. Differences were not significant when patients were stratified by ICU admission APACHE II scores. CONCLUSIONS: Patients recovering from sepsis breathe with a higher RVR, tend to have a lower MIP, and tend to be more likely to encounter first-day weaning failure compared to patients without sepsis. Our data also suggest that the severity of illness on ICU admission could explain some of these differences.

APACHE↗
PubMed1997

The position of AIDS in Pakistan, UAE and Jordan.

AIDS is a term used for Acquired Immuno-Deficiency Syndrome. It is, by definition, the end-stage disease manifestation of an infection with a virus called human immunodeficiency virus (HIV). The virus infects mainly two system of the body i.e. the immune system and central nervous system (CNS) and the occurrence of disease is due to the damage of these two systems. The statistics on AIDS are alarming, especially for Sub-Saharan Africa India. Some scientific studies indicated that upto one-third of all sexually active adults living in this region are already infected, up to 40% of all women and one in 10 to one in 5 children born in this part are actively infected with HIV and will be dead before having reached their fifth birthday. The information on HIV infected young adults were collected both from official and non-official sources of the following countries, Jordan, UAE, Pakistan. A big difference in number of patients was found between official and non-official data. Anyhow, both data (official & non-official) are alarming due to the increase in number of HIV cases. 21st century is especially dangerous to the next generation of Pakistan and Arab World because of increase in percentage of HIV cases during the last 5 years.

Journal Article↗
PubMed1997

Comparative bioavailability of sulfamethoxazole in three formulations of cotrimoxazole suspensions.

The pharmacokinetic parameters and relative bioavailability of sulfamethoxazole were estimated using three commercially available cotrimoxazole suspensions on six human volunteers. Maximum concentration in plasma was shown by product 1, i.e., 89.69+/-0.84 and were lower in products 2 and 3, i.e., 38.33+/-0.58 and 16.50+/-0.89, respectively. The time for maximum concentration was 4 hours in products 1 and 3 while it was 3.50 in product 2. There was prolonged elimination half-life of formulation 2 (7.50+/-0.94) than formulation 3 (7.43+/-0.54) while product 1 (4.54+/-0.15) showed lowest half-life. The values of absorption half-lives for formulations 1, 2 and 3 were 1.92+/-0.05. 1.80+/-0.41 and 2.78+/-0.25, respectively. The volume of distribution was highest in formulation 1 (0.9+/-0.00) lower in formulation 3 (0.40+/-0.03) and was lowest in formulation 2 (0.21+/-0.03). The values for total body clearance was lowest i.e., 0.24+/-0.00 in formulation 1, higher in formulation 2 i.e., 0.35+/-0.05 and still higher in formulation 3, i.e., 0.62+/-0.02. By taking the formulation 1, as standard (100%), the relative bioavailabilities of formulation 2 and 3 were 79.05 and 38.53%, respectively.

Journal Article↗
PubMed1997

The effect of anterior translation of the vertebra on the canal size in the lower cervical spine: a computer-assisted anatomic study.

Eighteen adult dry-bone spine specimens were used in conjunction with computer analysis to determine the average axial spinal canal area at the levels of C6, C7, and T1 after different degrees of anterior translation of the cephalad vertebra. Simulating a distractive flexion injury, the cephalad vertebra was anteriorly displaced on the caudal vertebra at 1-mm intervals. After each displacement, the remaining axial spinal canal area of the caudal vertebra was calculated. The results showed that the average axial spinal canal areas for both male and female specimens were approximately 222 mm2 for C6, 217 mm2 for C7, and 210 mm2 for T1, respectively. After a 6-mm anterior translation of the cephalad vertebra (assuming 50% of anterior translation of the vertebral body), the average axial spinal canal area of the caudal vertebra for both sexes significantly decreased to 59% at C6, 51% at C7, and 56% at T1, respectively. This study suggests that the size of the axial spinal canal directly depends on the degree of anterior vertebral translation.

Adult↗
PubMed1997

Bone marrow involvement in Hodgkin's disease: the significance of non-infiltrative changes.

We have tried to elucidate the significance of so called non-infiltrative changes in order to find their place in the staging procedure particularly in countries where facilities for elaborate clinical staging are not available. Seventy nine out of 88 patients were classified into 3 groups depending upon the histological findings in their bone marrow trephine biopsies. Bone marrow in Group-I (n = 20) patients was essentially normal. The established criteria of bone marrow involvement were fulfilled in Group III patients (n = 25); while bone marrow in Group-II patients (n = 34) showed non-infiltrative changes. The clinical presentation, peripheral blood parameters and LDH levels of the 3 groups of patients were compared. There was progressive anaemia, neutrophilic leucocytosis and increase in ESR from Group I to III. The change was statistically significant when Group I was compared with Group II or Group III but non-significant when Group II was compared with Group III. It is, therefore, postulated that both Groups II and III reflect the bone marrow involvement although the changes observed in Group II do not satisfy the previously established criteria for this purpose.

Adolescent↗
PubMed1997

Anatomic considerations of anterior instrumentation of the thoracic spine.

Forty-seven dry thoracic specimens from T-3 to T-12 (470 thoracic vertebrae) were used to measure the dimensions of the vertebral body of the thoracic spine and to determine the relationship of the posterior angulation of screw placement to the spinal canal from different entrance points. Statistically significant differences in dimensions of male and female specimens were found in the anterior vertebral body height and all of the angular measurements. The average maximum posterior angle relative to the frontal plane from T-3 to T-12 for both sexes ranged from 11 degrees to 14 degrees at the initial point (the level of the most anterior edge of the upper costal facet), from 20 degrees to 23 degrees at the point of 5 mm anterior to the initial point, and from 30 degrees to 34 degrees at the point of 10 mm anterior to the initial point. This study suggests that there is considerable risk of violating the spinal canal if the screws are inadvertently angled posteriorly. The authors recommend insertion of screws in the anterior or middle part of the lateral aspect of the vertebral body. The screws should be directed perpendicular to the lateral plane of the vertebral body. A posteriorly placed screw should be directed anteriorly.

Adult↗
PubMed1997

Pyuria as predictor of bacteriuria in catheterized patients.

Six hundred and nine urine samples were analyzed for pyuria to assess its efficacy as a predictor of bacteriuria, in catheterized patients, using different techniques of pus cells estimation. In 235 and 323 urine samples, pus cells were counted per high power field in centrifuged and uncentrifuged urine respectively, while in 51 urine samples pus cells were counted per cubic millimeter in uncentrifuged urine. All the urine samples were simultaneously cultured. Pyuria (pus cells > 10/HPF or CMM) was correlated with bacteriuria (colony count > 10(5) per ml). The overall efficacy of pyuria as a predictor of bacteriuria was low (52.01-60.78%) and there was no significant difference among the different techniques. It was concluded that pyuria as predictor of bacteriuria is the least reliable technique to be recommended in routine clinical practice.

Bacteriuria↗
PubMed1997

The bioavailability and pharmacokinetics of mefenamic acid in alloxan-diabetic rabbits.

The bioavailability and pharmacokinetics of mefenamic acid was studied in alloxan-diabetic rabbits. Mefenamic acid in plasma was assayed by high performance liquid chromatography. A paired t-test for normal and alloxan treated rabbits revealed a significant decrease in all the bioavailability and disposition kinetic parameters of mefenamic acid during diabetes was observed in the present study. The altered bioavailability and disposition of mefenamic acid in the diabetic state will require adjustment of the dosage regimen prescribed for diabetics in a clinical setting.

Animals↗
PubMed1996

Molecular ordering of the Fas-apoptotic pathway: the Fas/APO-1 protease Mch5 is a CrmA-inhibitable protease that activates multiple Ced-3/ICE-like cysteine proteases.

The Fas/APO-1-receptor associated cysteine protease Mch5 (MACH/FLICE) is believed to be the enzyme responsible for activating a protease cascade after Fas-receptor ligation, leading to cell death. The Fas-apoptotic pathway is potently inhibited by the cowpox serpin CrmA, suggesting that Mch5 could be the target of this serpin. Bacterial expression of proMch5 generated a mature enzyme composed of two subunits, which are derived from the pre-cursor proenzyme by processing at Asp-227, Asp-233, Asp-391, and Asp-401. We demonstrate that recombinant Mch5 is able to process/activate all known ICE/Ced-3-like cysteine proteases and is potently inhibited by CrmA. This contrasts with the observation that Mch4, the second FADD-related cysteine protease that is also able to process/activate all known ICE/Ced-3-like cysteine proteases, is poorly inhibited by CrmA. These data suggest that Mch5 is the most upstream protease that receives the activation signal from the Fas-receptor to initiate the apoptotic protease cascade that leads to activation of ICE-like proteases (TX, ICE, and ICE-relIII), Ced-3-like proteases (CPP32, Mch2, Mch3, Mch4, and Mch6), and the ICH-1 protease. On the other hand, Mch4 could be a second upstream protease that is responsible for activation of the same protease cascade in CrmA-insensitive apoptotic pathways.

Apoptosis↗
PubMed1996

Cost-saving approach to normal technetium-99m sestamibi myocardial perfusion scan.

We conducted a 1-year follow-up of 116 patients with normal poststress technetium-99m sestamibi without images at rest. Although 2 patients with proven coronary artery disease needed cardiac intervention, no patient suffered cardiac mortality or myocardial infarction, suggesting that early interpretation of normal poststress images without images at rest may imply an excellent prognosis for at least 1 year.

Coronary Disease↗
PubMed1996

The quantitative anatomy of the cervical nerve root groove and the intervertebral foramen.

STUDY DESIGN: The present study evaluated the cervical nerve groove and intervertebral foramen using dried vertebrae and cadaveric cervical spine. OBJECTIVES: To measure the cervical nerve groove in eight linear and one angular dimensions and the intervertebral foramen in two linear diameters. SUMMARY OF BACKGROUND DATA: Several anatomic studies of the cervical spine exist, but very little quantitative data have been reported on the cervical nerve groove. METHODS: Dried cervical vertebrae, C3-C7, from 41 complete vertebral sets (205 vertebrae) and 14 cadaveric cervical spine were obtained for the present study. Anatomic evaluation focused on the cervical nerve groove for dry specimens and intervertebral foramen for cadaveric specimens. Ten linear and one angular measurements were made bilaterally. The mean, range, and standard deviation were calculated for all of the specimens and for male and female specimens separately. RESULTS: Differences in dimensions of male and female specimens were not found to be statistically significant. The average lengths of the medial zone and distances from the midline of the vertebral body to the anterior border of the medial zone for male and female specimens consistently increased from C3 to C7. The width of the medial zone was larger in C3 than that of C4, C5, and C6 in male and female specimens. The minimum width for all levels ranged 1-2 mm. The medial zone depths gradually increased from C3 (3.2 mm for male and 2.3 mm for female specimens) to C7 (4.9 mm for male and 4.4 mm for female specimens). The smallest anteroposterior distances from the posterior midpoint of the lateral mass to the posterior border of the nerve groove were found in C7 (6.7 mm for male and 6.1 mm for female specimens). The general trend of the foraminal height and width increased from the cephalad to caudal except at C2-C3. CONCLUSIONS: These data may enhance understanding of the important bony elements associated with the cervical spinal nerves and roots as they pass through the cervical nerve groove and the intervertebral foramen.

Adult↗
PubMed1996

Genotoxicity of the Ganges water at Narora (U.P.), India.

Water samples were collected from the river Ganga at Narora (U.P.). High performance liquid chromatography analysis of water samples by the liquid extraction procedure indicated the presence of several pesticides such as DDT, alpha-BHC, aldrin, endrin and dieldrin at concentrations of 1.36, 1.38, 0.95, 0.61 and 0.41 ppb, respectively. The organophosphorus pesticides such as dimethoate and methyl parathion also appear to be present at concentrations of 0.20 and 0.41 ppb, respectively. The XAD water concentrates and liquid-liquid extracted water samples were assayed for mutagenic potential by the Ames Salmonella/microsome test. The test samples exhibited a significant degree of mutagenicity with TA102, TA100 and TA98 strains both in the presence and absence of DNA repair defective mutants, recA, lexA and polA of E. coli was observed as compared to their wild-type counterpart in the presence of XAD water concentrates.

Cell Division↗
PubMed1996

Antisense RNA to the putative tumor suppressor gene BRCA1 transforms mouse fibroblasts.

Recently, BRCA1, a familial breast and ovarian cancer susceptible gene has been cloned and shown to be either lost or mutated in families with breast and ovarian cancers. BRCA1 has been postulated to encode a tumor suppressor, a protein that acts as a negative regulator of tumor growth. We have characterized the BRCA1 gene products by Western blot and immunoprecipitation analysis in mouse and tumor cells. Multiple BRCA1 polypeptides of approximately 225, 185, 160, 145, 100, 52 and 38 kD were identified in these cells. BRCA1 proteins were found to be localized mainly in the nucleus of normal Rat1 cells and human breast cancer cells. In order to understand the role of BRCA1 in cell transformation, we have established a stable NIH3T3 cell line expressing BRCA1 antisense RNA. The inhibition of expression of endogenous BRCA1 protein was detected in NIH3T3 transfectants by Western blot analysis. The antisense BRCA1 expressing NIH3T3 cells showed accelerated growth rate, anchorage independent growth and tumorigenicity in nude mice unlike the parental and sense transfectants. These results provide the first direct biological evidence for the possible function of BRCA1 as a tumor suppressor gene.

3T3 Cells↗
PubMed1996

Modulation of kinin outflow from isolated perfused rat hearts by endothelin-1.

Bradykinin has previously been shown to suppress ET-1 secretion by endothelial cells. In the present study, rat isolated hearts have been perfused with Krebs solution using the Langendorff method. Immunoreactive bradykinin (IRBK) was measured in the perfusate and the basal level was found to be constant for up to 3 h. Ten min perfusions of the hearts with ET-1 at concentrations of 0.2-20 pM produced a dose-related suppression of kinin outflow by over 90% (P < 0.05). At these concentrations ET-1 had no detectable effect on the coronary vasculature or ECG. At 200 pM ET-1 and above, the hearts showed arrhythmias of increasing severity, accompanied at the highest doses by marked coronary constriction and an increase in IRBK outflow.

Animals↗