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Biomedical subjects

A Prasad

Publications and source records attributed to A Prasad.

At least 73 records · Page 4Linked to original sources
PubMed1999

Cardiac allograft valvulopathy: a case of donor-anorexigen-induced valvular disease.

We report on the transplantation of a cardiac allograft from a donor with prolonged exposure to anorexigens. This event allowed us to not only examine the early pathological alterations that characterize anorexigen-induced valvular damage, but to also study the posttransplantation outcome after the donor heart had been removed from the offending milieu. A donor history of anorexigen use should be sought, and if detected, careful evaluation for underlying valvular disease should be entertained. Early valvulopathy may appear clinically mild yet pathologically significant. Our single-case experience also suggests that anorexigen-induced valvulopathy may be a progressive disorder despite removal of the heart from the causative environment.

Adult↗
PubMed1999

Azaftig, a urinary proteoglycan from a cachectic cancer patient, causes profound weight loss in mice.

Cachexia is a complex medical condition characterized by significant weight loss associated with decreased body fat and protein; the condition may present itself with or without anorexia. We have isolated and partially characterized a proteoglycan (azaftig) from the urine of cancer and AIDS patients experiencing weight loss. When given to mice, the purified azaftig resulted in a significant decrease in body weight and body fat without any effect on appetite. The results of these studies show that azaftig may be one of the many factors participating in the emergence of the cachectic state.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Abnormal flow-mediated epicardial vasomotion in human coronary arteries is improved by angiotensin-converting enzyme inhibition: a potential role of bradykinin.

OBJECTIVES: This study was performed to determine whether angiotensin converting enzyme (ACE) inhibition improves endothelium-dependent flow-mediated vasodilation in patients with atherosclerosis or its risk factors and whether this is mediated by enhanced bradykinin activity. BACKGROUND: Abnormal coronary vasomotion due to endothelial dysfunction contributes to myocardial ischemia in patients with atherosclerosis, and its reversal may have an antiischemic action. Previous studies have shown that ACE inhibition improves coronary endothelial responses to acetylcholine, but whether this is accompanied by improved responses to shear stress remains unknown. METHODS: In 19 patients with mild atherosclerosis, metabolic vasodilation was assessed during cardiac pacing. Pacing was repeated during separate intracoronary infusions of low-dose bradykinin (BK) and enalaprilat. Endothelium-dependent and -independent vasodilation was estimated with intracoronary BK and sodium nitroprusside respectively. RESULTS: Enalaprilat did not alter either resting coronary vascular tone or dilation with sodium nitroprusside, but potentiated BK-mediated dilation. Epicardial segments that constricted abnormally with pacing (-5+/-1%) dilated (3+/-2%) with pacing in the presence of enalaprilat (p = 0.002). Similarly, BK at a concentration (62.5 ng/min) that did not alter resting diameter in the constricting segments also improved the abnormal response to a 6+/-1% dilation (p < 0.001). Cardiac pacing-induced reduction in coronary vascular resistance of 27+/-4% (p < 0.001) remained unchanged after enalaprilat. CONCLUSIONS: Thus ACE inhibition: A) selectively improved endothelium-dependent but not-independent dilation, and B) abolished abnormal flow-mediated epicardial vasomotion in patients with endothelial dysfunction, in part, by increasing endogenous BK activity.

Adenosine↗
PubMed1999

Glutathione reverses endothelial dysfunction and improves nitric oxide bioavailability.

OBJECTIVES: We investigated whether glutathione (GSH), a reduced thiol that modulates redox state and forms adducts of nitric oxide (NO), improves endothelium-dependent vasomotion and NO activity in atherosclerosis. BACKGROUND: Endothelial dysfunction and reduced NO activity are associated with atherosclerosis and its clinical manifestations such as unstable angina. METHODS: In the femoral circulation of 17 patients with atherosclerosis or its risk factors, endothelium-dependent vasodilation with acetylcholine (ACH), and endothelium-independent vasodilation with nitroglycerin and sodium nitroprusside were studied before and after GSH. In 10 patients, femoral vein plasma cyclic guanylate monophosphate (cGMP) levels were measured during an infusion of ACH before and after GSH. Femoral artery flow velocity was measured using a Doppler flow wire and the resistance index (FVRI) calculated as mean arterial pressure divided by flow velocity. RESULTS: Glutathione strongly potentiated ACH-mediated vasodilation; at the two doses, FVRI decreased by 47% and 56% before, and by 61% and 67% after GSH (p = 0.003). Glutathione also elevated cGMP levels in the femoral vein during ACH infusion from 17.6 +/- 3 to 23.3 +/- 3 pmol/ml (p = 0.006). Augmentation of ACH responses was only observed in patients with depressed endothelial function. Glutathione did not influence endothelium-independent vasodilation with either NO donor. CONCLUSIONS: Thiol supplementation with GSH selectively improves human endothelial dysfunction by enhancing NO activity.

Acetylcholine↗
PubMed1999

Pili bigeminy induced by low fluence therapy with hair removal alexandrite and ruby lasers.

BACKGROUND: Lasers are being widely used for the hair removal. Several complications including hyperpigmentation, erythma, hypopigmentation, and burns have been reported. OBJECTIVE: To study laser hair removal complications. METHODS: Pubic hairs were treated with alexandrite and ruby lasers. RESULTS: Pili Bigeminy can be induced by low fluence therapy with hair removal Alexandrite and Ruby lasers as a complication. CONCLUSION: To our knowledge, this is the first report of pili bigminy as a complication of laser-assisted hair removal.

Adult↗
PubMed1999

Pediatric genitourinary tumors.

Advances in our knowledge of pediatric genitourinary tumors are being made at a rapid pace at both the basic science and clinical levels. As the molecular mechanisms underlying these malignancies are being uncovered, treatment options are being modified to decrease morbidity and, ultimately, increase survival. This article reviews the recent literature on Wilms' tumor, rhabdomyosarcoma, and testicular tumors.

Child↗
PubMed1999

Nonsteroidal anti-inflammatory drugs in the management of pain and inflammation: a basis for drug selection.

Nonsteroidal anti-inflammatory drugs (NSAIDs) are a group of agents with similar action but diverse chemical structures and mechanism of action. There is considerable interpatient variability in the pain relief obtained from NSAIDs even when these agents belong to the same chemical family. The reasons for this interpatient variability include pharmacodynamic actions, pharmacokinetic parameters, or a combination of both. Furthermore, two distinct forms of the key enzyme cyclo-oxygenase (COX) have been identified. The constitutive enzyme COX-1 is found in most tissues and is believed to confer gastric mucosal protective action, and COX-2, the inducible enzyme, is implicated in pain and inflammation. Selective inhibition of COX-1 and COX-2 may allow prediction of drugs' major effects. By definition, NSAIDs are expected to modulate synovial inflammation present in the arthritic joints. Whether NSAIDs can positively influence the progression of arthritic disorders by modifying the underlying pathology remains to be answered. This review provides guidelines on how to choose NSAIDs rationally keeping in view the mechanism of tissue injury, the mode of action of NSAIDs, and their adverse effects.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Characteristic distributions of finite-time Lyapunov exponents.

We study the probability densities of finite-time or local Lyapunov exponents in low-dimensional chaotic systems. While the multifractal formalism describes how these densities behave in the asymptotic or long-time limit, there are significant finite-size corrections, which are coordinate dependent. Depending on the nature of the dynamical state, the distribution of local Lyapunov exponents has a characteristic shape. For intermittent dynamics, and at crises, dynamical correlations lead to distributions with stretched exponential tails, while for fully developed chaos the probability density has a cusp. Exact results are presented for the logistic map, x-->4x(1-x). At intermittency the density is markedly asymmetric, while for "typical" chaos, it is known that the central limit theorem obtains and a Gaussian density results. Local analysis provides information on the variation of predictability on dynamical attractors. These densities, which are used to characterize the nonuniform spatial organization on chaotic attractors, are robust to noise and can, therefore, be measured from experimental data.

Journal Article↗
PubMed1999

Overdiagnosis and overtreatment of Lyme neuroborreliosis are preventable.

The problems of diagnosis and treatment of Lyme neuroborreliosis can be minimised by strictly following the clinical diagnostic criteria, and understanding the pitfalls of laboratory tests. The diagnosis is based solely on objective clinical findings, with serologic test results used only to confirm the diagnosis. It must be underscored that serologic testing, when ordered without regard for clinical presentation (i.e., used as a screen), may be misleading due to its extremely low positive predictive value. Enzyme-linked immunosorbent assay should always be confirmed by Western blot. The cerebrospinal fluid Borrelia burgdorferi antibody index is more meaningful than simple titres of specific antibody. Polymerase chain reaction is still a research tool and should not be utilised without clinical correlation. All serologic tests and polymerase chain reaction may remain positive long after successful treatment. Overdiagnosis and overtreatment can be minimised by following these guidelines.

Algorithms↗
PubMed1999

Cytologic grading and DNA image cytometry of breast carcinoma on fine needle aspiration cytology smears.

OBJECTIVE: To correlate the cytologic grade of breast carcinoma with DNA image cytometry (ICM) and nuclear area on fine needle aspiration cytology (FNAC) smears. STUDY DESIGN: In this prospective study, FNAC material from 28 breast carcinomas were studied for cytologic grade and DNA ICM. Breast carcinomas were classified as grade 1-3 (low to high). DNA histograms were classified by the modified Auer method. Degree of hyperploidy (DH), ploidy balance (PB) and nuclear area (NA) were measured on Feulgen-stained smears by a CAS 200 image cytometer. Cytologic grade was correlated with DNA ICM findings and NA. RESULTS: There were 3 cytologic grade 1, 13 grade 2 and 12 grade 3 breast carcinomas. Seven of eight cases of hypertetraploid aneuploidy were grade 3 tumors. All cytologic grade 1 tumors were diploid. There were significant differences in DH, PB and NA in different grades of breast carcinoma (one-way ANOVA). CONCLUSION: DNA image cytometry in combination with cytologic grading might offer additional information for the characterization of breast carcinomas diagnosed by FNAC. These observations are of particular interest with the introduction of preoperative chemotherapy.

Adult↗
PubMed1999

Studies on the viability of metacercariae of Fasciola gigantica.

The viability of metacercariae of Fasciola gigantica was tested by in vitro and in vivo methods. In vitro testing was based upon the motility of juvenile flukes within the inner cyst as examined under the light microscope. In vivo testing was undertaken through experimental infections of rabbits (two groups) and natural definitive hosts, lambs (one group). In the first group, out of six rabbits each given 25 metacercariae, worm establishment only took place in one rabbit with a single fluke recovery on 60 days post infection. In the second group of six rabbits each given 200 metacercariae, five were infected, with two or three flukes per host. All the lambs given 250 metacercariae became infected showing prevalences of 7.2-40% in comparison with rabbits in which low prevalences (0-4%) were recorded. The results indicated that even viable metacercariae which were already tested in vitro could not readily establish in rabbits. Such variability in worm establishment suggests that immunological and chemotherapeutic studies in rabbits infected with F. gigantica are likely to be unreliable.

Animals↗
PubMed1999

Retinopathy progression and visual outcomes after phacoemulsification in patients with diabetes mellitus.

PURPOSE: To determine the rate of progression of diabetic retinopathy following phacoemulsification surgery and to determine if surgeon experience and/or surgical duration adversely affect visual outcome. METHODS: A retrospective review of 150 eyes of 119 diabetic patients who underwent phacoemulsification surgery over a 5-year period was performed. Data collected included patient age, sex, type and duration of diabetes, diabetic control, associated systemic health factors, preoperative visual acuity and retinopathy grade, duration of surgery, intraoperative complications, and postoperative course. The effect of these factors on visual outcome and rate of retinopathy progression was studied. Resident and private cases were compared. RESULTS: The visual acuity improved by two or more lines in 117 eyes (78%). Ninety-three eyes (62%) had a final visual acuity greater than or equal to 20/40. Retinopathy progression was seen in 37 eyes (25%) followed up for 6 to 10 months. Preoperative nonproliferative diabetic retinopathy, prolonged surgical duration, and limited surgical experience were statistically associated with retinopathy progression. CONCLUSIONS: The visual results and rate of retinopathy progression after phacoemulsification surgery in our series do not appear to differ significantly from those reported using other techniques. Nonproliferative diabetic retinopathy, longer surgical duration, and surgical inexperience resulted in an increased rate of retinopathy progression.

Aged↗
PubMed1999

Pictorial CME.

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Foreign-Body Reaction↗