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Biomedical subjects

Masood Ahmad

Publications and source records attributed to Masood Ahmad.

At least 19 recordsLinked to original sources
PubMed2007

B-type natriuretic peptide is not a marker of ischemia during dobutamine stress echocardiography.

Elevated levels of B-type natriuretic peptide (BNP) have been reported in association with exercise-induced ischemia. Data regarding BNP as a marker of ischemia during dobutamine stress echocardiography (DSE) are not conclusive. This study was designed to evaluate changes in BNP during DSE. A total of 74 patients referred to rule out ischemia by DSE were enrolled in the study. All patients had DSE using standard protocol. Of 74 patients enrolled, 6 were excluded because of nondiagnostic tests. Of the remaining 68 patients, 15 had positive DSE and 53 were negative for ischemia. The BNP levels (mean +/- SD) in the patients without ischemia were 42.5 pg/mL (+/-SD 47.6) at baseline and 41.9 pg/mL (+/-SD 48.9) at peak, and the measurements in the patients with ischemia were 90 pg/mL (+/-SD 171.7) at baseline and 88 pg/mL (+/-SD 149.2) at peak. BNP levels do not change during DSE with or without evidence of ischemia.

Adult↗
PubMed2006

Genotoxicity of industrial wastewaters obtained from two different pollution sources in northern India: a comparison of three bioassays.

The genotoxicity of industrial wastewater samples from Aligarh and Ghaziabad cities was compared using the Ames plate incorporation test, the Ames fluctuation test and the Allium cepa test. While TA102 and TA104 strains exhibited the highest sensitivity against the Aligarh sample (AWW) in terms of the slope (m) of the dose-response curve in the plate incorporation assay, TA98 and TA97a were the most sensitive strains based on the induction factor, Mi(p). TA98 once again, was the most sensitive strain against the test sample from Ghaziabad (GWW) in terms of 'Mi(p)' while TA102 was the most sensitive strain on the basis of the slope (m). TA100 displayed the highest susceptibility towards the samples from Aligarh in the fluctuation test. However, TA102 and TA98 responded maximally to GWW in this bioassay. The mutagenicity of the test samples seemed to be partly mediated by reactive oxygen species (ROS) as evidenced by the use of free radical scavengers. Mannitol brought about the maximum decline in the number of revertants of TA102 by the Aligarh sample, whereas such a reduction in case of Ghaziabad sample was exhibited with superoxide dismutase. Both the test water samples induced various anaphase aberrations in the root cells of Allium cepa. Fragmentation of the chromosome was the predominant effect of the Aligarh water sample while the Ghaziabad sample induced chromosome stickiness. The crucial roles of heavy metals and pesticides in the genotoxicity of AWW and GWW, respectively, have been suggested. In view of the problem associated with the interpretations of data, we recommend that all the test bioassays should be carried out in the presence of ROS scavengers for the fool proof evaluation of the genotoxicity of water samples.

Allium↗
PubMed2006

An unusual complication after aortic valve replacement.

Pseudoaneurysm of the mitral-aortic intervalvular fibrosa, though rare, can occur after aortic valve replacement. We report an asymptomatic patient who developed this unusual complication and describe the use of transesophageal and 3-dimensional echocardiography to help confirm the diagnosis.

Adult↗
PubMed2006

Detoxification and bioremediation potential of a Pseudomonas fluorescens isolate against the major Indian water pollutants.

A Pseudomonas fluorescens strain was isolated from the soil of industrial estate of Aligarh, India. This strain was resistant to some of the major Indian water pollutants, namely Cd2+, Cr6+, Cu2+, Ni2+, Pb2+, BHC, 2,4-D, mancozeb and phenols up to the levels occurring in the highly polluted regions. Moreover, the test strain seems to have a great potential for the detoxification of these pollutants. The decrease in toxicity as determined by the Allium cepa test was recorded as 62.5% for the model water containing the mixture of test heavy metals, 71.9% for the pesticides, 73.2% for phenols, and 58.5% for combination of all these toxicants. These values were obtained after 24 hours, exposure to the immobilized cells of the test isolate in the calcium alginate matrix at the concentrations of these polutants supposedly present in the highly polluted water systems in India. The efficiency of bioremediation for certain heavy metals at the same concentrations by means of immobilized cells of the test Pseudomonas fluorescens isolate was estimated to be 75.9% for cadmium, 74.2% for hexavalent chromium and 61.0% for lead during the 24 hours' treatment. In view of the preliminary work, the test isolate seems to be a good candidate for the bioremediation of water pollutants.

Biodegradation, Environmental↗
PubMed2006

Left ventricular diastolic filling characteristics are not impaired but systolic performance was augmented in the early hours of experimental endotoxemia in humans.

This study was performed to determine whether endotoxemia causes diastolic cardiac dysfunction. Eleven healthy volunteers, 30 +/- 6 years of age, underwent comprehensive transthoracic echocardiographic assessment including two-dimensional, M-mode transmitral and tissue Doppler of systolic and diastolic function at baseline and at 3 and 5 h after intravenous administration of purified Escherichia coli endotoxin (4 ng/kg). Data were analyzed by analysis of variance; P values of less than 0.05 were considered significant. Endotoxin administration resulted in a hyperdynamic state characterized by decreased mean arterial pressure and significant increase in cardiac index. This was accompanied by increases in several load-dependent systolic performance indices (3 and 5 h). Robust increases in peak systolic blood pressure/end-systolic volume index, one of the relatively load-independent contractility parameter, were also observed at 3 h after endotoxin administration. Transmitral peak early velocity (E), which represents early filling, significantly increased at 3 h after infusion. Late diastolic velocity (A), which represents atrial contraction, significantly increased at 3 and 5 h after infusion. The E/A ratio indicative of delayed relaxation significantly decreased due to increases in A (transmitral) and A (tissue Doppler) at 3 and 5 h after infusion. As expected, endotoxin infusion resulted in a hyperdynamic state associated with increases in systolic function indices including endocardial systolic velocities. The observed decreases in E/A (transmitral) and E/A (tissue Doppler) ratio were primarily due to increases in A and A. Moreover, isovolumic relaxation time and time constant for left ventricular relaxation, a load-independent parameter for ventricular relaxation, remained unchanged at 3 and 5 h after endotoxin infusion. Therefore, our findings are more likely due to enhanced atrial contractility resulting from increased sympathetic activity in response to reduction in left ventricular afterload and not due to altered diastolic filling characteristics.

Adult↗
PubMed2006

Assessment of left atrial appendage by live three-dimensional echocardiography: early experience and comparison with transesophageal echocardiography.

BACKGROUND: Live Three-Dimensional Echocardiography (L3D, Sonos 7500, Philips) has the potential to visualize all cardiac structures including left atrial appendage (LAA). We tested the feasibility of evaluating LAA by L3D and compared the findings to transthoracic echocardiography (2D) and in a subset of patients with transesophageal echocardiography (TEE). METHODS: L3D images were obtained in 204 consecutive patients referred for routine 2D or TEE. We performed wide-angled acquisitions from parasternal and apical views. TomTec system (4D Cardio-view, RT 1.2) was used to visualize LAA from multiple vantage points. RESULTS: LAA was adequately visualized by L3D in 139 of 204 (68.1%) patients. L3D visualization was dependent on image quality, suboptimal in 100 and diagnostic in 104 patients. Overall, LAA was visualized in 93 (45.5%) patients by 2D compared to 139 (68.1%) by L3D (P < 0.0001). In 100 patients with suboptimal image quality by L3D, LAA visualization was 16% by 2D and 35% by L3D, whereas in 104 patients with diagnostic images, LAA was visualized in 77 (74%) by 2D and in all 104 (100%) patients by L3D (P < 0.0001). In 37 patients referred for transesophageal echocardiography (TEE), live three-dimensional echocardiography (L3D) visualized left atrial appendage (LAA) in 34 patients with diagnostic image quality. Eight patients with LAA thrombi on TEE had thrombi detected by L3D as well. All patients with LAA thrombus had enlarged LA by both 2D and TEE. CONCLUSIONS: L3D is a promising technique in evaluation of LAA with and without thrombi. In patients with good quality transthoracic images L3D may be used as a screening tool in assessment of LAA.

Adult↗
PubMed2005

Benefits, unresolved questions, and technical issues of cardiac resynchronization therapy for heart failure.

This review aims to provide a synthesis of the published evidence regarding the rationale and clinical benefits of cardiac resynchronization therapy (CRT) with implantable atrial-synchronized biventricular pacing (BVP) devices in patients with moderate to advanced heart failure and intra- and interventricular conduction delays. In addition, it addresses clinical and technical issues that have yet to be resolved, such as the selection of the most suitable candidates for CRT; the usefulness of combining BVP with automatic defibrillation backup; the value of CRT in patients with atrial fibrillation; the importance of alternative sites of pacing, such as the atrial septum and the right ventricular (RV) outflow tract; the harmful effects of the long-standing practice of producing an iatrogenic left bundle branch block by conventional RV pacing in patients receiving standard permanent pacemakers; the question of precisely where on the left ventricle optimal pacing is achieved; and the potential applications of CRT in patients with pediatric or congenital heart disease. Considering how major advances have been achieved since the first clinical application of CRT in 1994, one can be optimistic about the future of the electrotherapeutic management of heart failure.

Cardiac Pacing, Artificial↗
PubMed2005

Allium cepa derived EROD as a potential biomarker for the presence of certain pesticides in water.

Allium cepa root length inhibition test is a well recommended bioassay for the evaluation of the toxicity of various polluted waters. The utility of EROD (7-ethoxy resorufin O-deethylase) as a potential biomarker of pesticide pollution was investigated using the Allium cepa system. Onion bulbs exposed to model water samples containing any of the six pesticides viz. 2,4-D, HCB, malathion, carbaryl, DDT and endosulphan were analyzed for EROD activity. The pesticide treatment resulted in the enhanced activity of the enzyme, with carbaryl and HCB causing 63- and 53-fold induction respectively with respect to the control at a dose of 1.2 ppb. The industrial wastewater samples from Ghaziabad city of Northern India resulted in about a 68-fold rise in the EROD activity, whereas the Aligarh samples did not exhibit any change within the statistical limit. These results suggest the presence of the test pesticides in the Ghaziabad sample and their absence in the Aligarh sample. Pesticide analysis in the test water samples by HPLC supported this to a large extent. Presence of cycloheximide in the test system brought down the EROD activity, equal to that of control, suggesting the de novo synthesis of the enzyme following the exposure of Allium cepa to pesticides. These studies suggest that the Allium cepa derived EROD can act as a potential biomarker of certain pesticides since even 1ppb of total/individual pesticides brought about >10-fold induction of EROD. We recommend the assay of EROD in the Allium cepa system as a presumptive test for the detection of these pesticides before using analytical techniques like HPLC.

Biomarkers↗
PubMed2005

Certain antioxidant enzymes of Allium cepa as biomarkers for the detection of toxic heavy metals in wastewater.

The utility of antioxidant enzymes, viz glutathione-S-transferase (GST), glutathione reductase (GR), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione peroxidase (GPX), monodehydroascorbate reductase (MDHAR) and dehydroascorbate reductase (DHAR), as biomarkers of heavy metal pollution in water was investigated using the Allium cepa (onion) system. These antioxidant enzymes were assayed in onion bulbs exposed to certain heavy metals taken separately, the test metals taken in combination as well as the industrial wastewater especially found to contain these metals. GST exhibited significantly enhanced activity upon treatment with individual heavy metals. However, GR, SOD and CAT did not show such a pronounced increase in activities. At higher heavy metal concentrations, GR, SOD and CAT showed a steep decline while GST activity still showed a rise. Moreover, APX, GPX and MDHAR also exhibited remarkable induction with increase in the concentration of individual heavy metals. However, there was no significant change in DHAR activity with respect to the controls. Metabolites like ascorbate (ASC) and glutathione (GSH) exhibited significant decline with increase in the concentration of individual heavy metals while the level of H(2)O(2) continued to display the rise up to a heavy metal concentration of 100 microM, after which it showed a gradual decline. A. cepa bulbs treated with wastewater sample showed enzyme activity profiles similar to that shown with heavy metals, thereby suggesting the presence of heavy metals in the test wastewater. Atomic absorption spectrophotometry also detected large amounts of Cd, Cr, Cu, Hg, Pb and Zn in the test water sample. The metal mixture, containing the amounts of heavy metals equivalent to those found in the wastewater, resulted in steep declines in GR, SOD and CAT activities in A. cepa while GST showed a rise. However, when this metal mixture was diluted to 2000-fold, GR, SOD and CAT also showed enhanced activities compared with the controls. Contrary to the above finding, APX, GPX and MDHAR exhibited the rise in activities in A. cepa exposed to the metal mixture at all dilutions. In the presence of cycloheximide, all the enzymes returned to the levels of untreated controls while chloramphenicol did not have any effect on the test enzymes, thereby suggesting de novo protein synthesis of the test antioxidant enzymes in the cytosolic compartment of the cell as a result of exposure to the heavy metals.

Antioxidants↗
PubMed2005

Color M-mode flow propagation velocity and conventional doppler indices in the assessment of diastolic left ventricular function during isometric exercise.

BACKGROUND AND OBJECTIVE: Color M-mode flow propagation velocity (Vp) was shown to be a preload-independent measure of diastolic function. To study the effects of an increase in afterload induced by isometric handgrip exercise on diastolic function assessment in patients with cardiomyopathy, we measured Vp and conventional Doppler indices at baseline and at 30% of predetermined maximum handgrip strength. METHODS: Twenty-four patients with systolic dysfunction were divided into two groups: Group I comprising 12 patients with E/A < 1 (early filling velocity/atrial contraction velocity) and Group II comprising 12 patients with E/A > 1. All the patients underwent measurement of Vp, E velocity, its deceleration time (DT), A velocity, isovolumic relaxation time (IVRT), and pulmonary atrial flow reversal velocity (PFR) at baseline and at 30% of predetermined maximum handgrip strength. Twelve healthy controls underwent these same measurements. RESULTS: When comparing baseline to peak echocardiographic data, no significant changes were noted in Vp in any of the groups while a shift of pulsed Doppler indices of Group I toward a pattern closer to that of Group II was noted and a decrease in E velocity and E/A ratio with an increase in IVRT occurred in healthy controls. CONCLUSIONS: Color M-mode flow propagation velocity seems to be an afterload-independent measure of diastolic function in patients with moderate to severe cardiomyopathy while pulsed Doppler indices are more sensitive to loading conditions induced by isometric exercise.

Blood Flow Velocity↗
PubMed2005

Crimean-Congo hemorrhagic fever outbreak in Rawalpindi, Pakistan, February 2002: contact tracing and risk assessment.

A 25-year-old woman, later identified as index case of Crimean-Congo hemorrhagic fever (CCHF), presented to Holy Family Hospital in Rawalpindi, Pakistan with fever and generalized coagulopathy. A retrospective contact tracing was conducted to explore the modes of exposure possibly associated with transmission of CCHF infection among contacts. We traced 32 contacts of the index case and 158 contacts of secondary cases and tested them for IgG and IgM antibodies against CCHF virus by an enzyme-linked immunosorbent assay technique. According to the type of exposure, contacts were divided into five subsets: percutaneous contact with blood, blood contact to unbroken skin, cutaneous contact to non-sanguineous body fluids, physical contact with patients without body fluids contact, and close proximity without touching. Two out of four contacts who reported percutaneous exposure tested positive for antibodies to CCHF virus. We conclude that simple barrier methods and care in provision of CCHF cases may prevent transmission of this infection.

Adult↗
PubMed2004

Acute onset of severe dilated cardiomyopathy during bromocriptine therapy.

OBJECTIVE: To report a case of severe dilated cardiomyopathy (DCMP) in a patient on bromocriptine therapy for a microprolactinoma. CASE SUMMARY: A 31-year-old African American female, who had been receiving bromocriptine 5 mg orally daily for a microprolactinoma during the preceding month, developed severe DCMP. An echocardiogram showed a markedly dilated left ventricle with severe reduction in the left-ventricular ejection fraction in the absence of any other identifiable causes of DCMP such as a peripartum state, ethanol use, preceding systemic viral illness, chronic hypocalcemia, chronic hypophosphatemia, or chronic uncontrolled tachycardia. She improved substantially (both symptomatically and echocardiographically) after cessation of bromocriptine therapy and initiation of supportive treatment of congestive heart failure (CHF). She showed no recurrence of CHF at a follow-up visit 2 months after withdrawal of the supportive care. The patient was not rechallenged with bromocriptine due to the clinical/ethical gravity of this probable adverse effect. DISCUSSION: Although cardiopulmonary adverse effects have been reported with the use of cabergoline (another dopamine agonist), to the best of our knowledge, this is the first case report of severe life-threatening DCMP associated with bromocriptine therapy. Causality assessment using the Naranjo probability scale revealed that the adverse drug event was probable. CONCLUSIONS: Bromocriptine was probably associated with DCMP in a patient being treated for a microprolactinoma. Severe DCMP needs to be considered a potentially life-threatening but reversible adverse effect of bromocriptine therapy for microprolactinoma of the pituitary gland.

Acute Disease↗
PubMed2004

A case of atrial fibrillation from cyclosporine toxicity.

We describe the unusual occurrence of atrial fibrillation immediately after a seizure in a young patient with cyclosporine toxicity. The new onset atrial fibrillation was triggered by high levels of cyclosporine and possibly facilitated by the electrolyte imbalances post seizure and the presence of underlying mild left atrial enlargement.

Journal Article↗
PubMed2004

Rapid screening of cardiac patients with a miniaturized hand-held ultrasound imager--comparisons with physical examination and conventional two-dimensional echocardiography.

BACKGROUND: Rapid screening of cardiac patients with a hand-held ultrasound imager (SonoHeart [SH]) could provide valuable clinical information. HYPOTHESIS: Whether the use of this device yields additional information to a carefully conducted physical examination and comparable findings to those of conventional two-dimensional echocardiography (2-D) during inpatient rounds is not well established and is the subject of this study. METHODS: In all, 100 consecutive telemetry patients underwent rapid screening with 2-D and color Doppler SH during inpatient rounds. SonoHeart findings were compared with results from conventional 2-D and physical examination conducted by an attending cardiologist. RESULTS: All patients had interpretable images. Mean scanning time with SH was 5.0 +/- 1.2 min; 2-D and SH findings were comparable. The parameters studied included chamber sizes, left ventricular (LV) systolic function, presence of LV hypertrophy (LVH), wall motion abnormalities (WMA), pericardial effusion (PE), and valvular regurgitations. Mild to moderate valvular regurgitation and LV systolic dysfunction were reliably diagnosed by SH in a number of patients whose symptoms were unrelated to the abnormalities detected. CONCLUSIONS: Rapid screening with SH provides accurate and valuable information that would otherwise be undetected during physical examination. Its introduction into clinical practice may redefine the initial approach to patients with cardiovascular disease.

Cardiovascular Diseases↗