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Biomedical subjects

A Yadav

Publications and source records attributed to A Yadav.

At least 19 recordsLinked to original sources
PubMed2006

Paramagnetic particles and mixing in micro-scale flows.

Mixing in microscale flows with rotating chains of paramagnetic particles can be enhanced by adjusting the ratio of viscous to magnetic forces so that chains dynamically break and reform. Lattice Boltzmann (LB) simulations were used to calculate the interaction between the fluid and suspended paramagnetic particles under the influence of a rotating magnetic field. Fluid velocities obtained from the LB simulations are used to solve the advection diffusion equation for massless tracer particles. At relatively high Mason numbers, small chains result in low edge velocities, and hence mixing is slower than at other Mason numbers. At low Mason numbers, long, stable chains form and produce little mixing toward the center of the chains. A peak in mixing rate is observed when chains break and reform. The uniformity of mixing is greater at higher Mason numbers because more small chains result in a larger number of small mixing areas.

Algorithms↗
PubMed2006

Dynamics of rotating paramagnetic particles simulated by lattice Boltzmann and particle dynamics methods.

Novel biochemical sensors consisting of rotating chains of microscale paramagnetic particles have been proposed that would enable convenient, sensitive analyte detection. Predicting the dynamics of these particles is required to optimise their design. The results of lattice Boltzmann (LB) and particle dynamics (PD) simulations are reported, where the LB approach provides a verified solution of the complete Navier-Stokes equations, including the hydrodynamic interactions among the particles. On the other hand, the simpler PD approach neglects hydrodynamic interactions, and does not compute the fluid motion. It is shown that macroscopic properties, like the number of aggregated particles, depend only on the drag force and not on the total hydrodynamic force, making PD simulations yield reasonably accurate predictions. Relatively good agreement between the LB and PD simulations, and qualitative agreement with experimental data, are found for the number of aggregated particles as a function of the Mason number. The drag force on a rotating cylinder is significantly different from that on particle chains calculated from both simulations, demonstrating the different dynamics between the two cases. For microscopic quantities like the detailed force distributions on each particle, the complete Navier-Stokes solution, here represented by the LB simulation, is required.

Computer Simulation↗
PubMed2006

Assessment of total thrombus load in symptomatic patients with venous thromboembolism.

Pulmonary embolism (PE) and Deep vein thrombosis (DVT) are separate but related aspects of the same dynamic process termed as venous thrombembolism (VTE). The existing Asian literature has shown a wide variation in the prevalence of VTE, with very limited data from the Indian subcontinent. Between January 2001 and July 2004, 1,552 patients with clinically suspected lower limb DVT underwent a combined ascending radionuclide venogram and lung perfusion scan for assessment of the total thrombus burden. Of 744 patients with radionuclide venography proven DVT, 294 (40%) had a high probability lung scan. Nearly half of these patients were asymptomatic for pulmonary embolism. The high prevalence of PE in patients with DVT suggests the need for evaluation of thrombus load in the venous as well as pulmonary circulation. A combination radionuclide ascending venography with lung perfusion scan is a useful and reliable single test for this purpose.

Adult↗
PubMed2005

Prevalence of parenterally transmitted hepatitis viruses in clinically diagnosed cases of hepatitis.

Hepatitis B virus (HBV) is the most important causative agent of blood borne hepatitis in humans. Hepatitis D Virus (HDV) infection occurs either as a coinfection or superinfection in HBV carriers. Hepatitis C virus (HCV) is the major cause of transfusion non-A, non-B hepatitis and continues to be a major cause of human liver disease throughout the world. The present study was conducted on 70 clinically diagnosed cases of viral hepatitis to study the prevalence of parenterally transmitted viral hepatitis. The serum samples were tested for HBsAg, HBeAg, IgM anti-HBc, anti-HBe, anti-HCV and anti-HDV using separate ELISA kits. Of the 70 serum samples tested, 28 (40%) were positive for HBsAg out of which 3 (4.28%) were positive for HBeAg also. Five (7.1%) of the HBsAg positive cases tested positive for IgM anti-HBc also. HBsAg alone was found in 17 (24.28%) cases. The prevalence of anti-HCV was 3 (4.28%) in 70 cases. Thus early screening of clinically diagnosed cases of viral hepatitis is essential for establishing diagnosis and treatment to prevent long term sequelae.

Adult↗
PubMed2005

Successful pregnancy in untreated limited Wegener's granulomatosis.

A thirty four year old female presented with upper and lower respiratory symptoms in the third trimester of pregnancy. After the delivery of a healthy baby, the symptoms progressed to involve multiple organ systems and eventually a diagnosis of limited Wegener's Granulomatosis (Carrington-Liebow syndrome) was made. The extremely rare combination of WG and pregnancy, especially the onset of disease in late pregnancy is discussed. The successful outcome of pregnancy even without treatment of WG is the highlight of the case.

Adult↗
PubMed2004

Interaction of Ising-Bloch fronts with Dirichlet boundaries.

We study the Ising-Bloch bifurcation in two systems, the complex Ginzburg Landau equation (CGLE) and a FitzHugh Nagumo (FN) model in the presence of spatial inhomogeneity introduced by Dirichlet boundary conditions. It is seen that the interaction of fronts with boundaries is similar in both systems, establishing the generality of the Ising-Bloch bifurcation. We derive reduced dynamical equations for the FN model that explain front dynamics close to the boundary. We find that front dynamics in a highly nonadiabatic (slow front) limit is controlled by fixed points of the reduced dynamical equations, that occur close to the boundary.

Journal Article↗
PubMed2003

Giant cell reparative granuloma of the base of the skull presenting as a parapharyngeal mass.

Giant cell reparative granuloma is an infrequent non-tumoral lesion affecting the maxillary and mandibular bones and only rarely, the cranial bones. We report a case of giant cell reparative granuloma of the base of the skull in a 12-year-old female who presented with a parapharyngeal mass. Computerized Tomography (CT) showed the intracranial extension and destruction of surrounding bones.

Bone Diseases↗
PubMed2003

Prevalence of initial drug resistance to M. tuberculosis in new sputum positive RNTCP patients.

There is an increased prevalence of drug resistant M. tuberculosis strains and of these, multi drug resistant organisms are of particular concern. With the implementation of Revised National Tuberculosis Control Programme (RNTCP) allover the state of Delhi, Initial drug resistance (IDR) to Isoniazid and Rifampicin assumes great importance and needs to be monitored on a regular basis. We undertook to study the IDR against the first line essential drugs i.e. Isoniazid (H), Rifampicin (R), Ethambutol (E) and Streptomycin (S) from April 1999 to March 2000 in newly diagnosed sputum positive cases of pulmonary tuberculosis attending TB clinics under RNTCP in Delhi. A total of 157 consecutive new smear positive patients attending TB clinics under RNTCP were taken into the study. All sputum samples were subjected to culture and drug sensitivity tests on LJ medium after decontamination of samples by Petroff's method. Resistance was expressed as the percentage of colonies that grow on critical concentration of the drugs. To determine the proportion of resistance, the number of colonies on the control and the number of colonies on the drug medium were determined. A total of 94.77% samples were sensitive to the four first line essential drugs and IDR to any drug was 5.22%. The resistance to Rifampicin alone was nil but the resistance to Isoniazid alone was 2.24%. Combined resistance to both Rifampicin and Isoniazid was 2.98 %. The incidence of resistance to first line drugs in tuberculosis is not very high among new sputum positive patients attending TB clinics under RNTCP.

Antitubercular Agents↗
PubMed2001

Study of resistance against some ionophores in Eimeria tenella field isolates.

Three Eimeria tenella field isolates from Gurgaon district of Haryana (north India) were studied in a battery test for evaluating drug resistance against two currently used ionophores; maduramicin (5ppm) and salinomycin (60ppm). Broiler birds (Ross strain) were infected with 10(5) sporulated oocysts each at the age of 2 weeks and prophylactic medication commenced 2 days prior to infection. Drug resistance was assessed by calculating the global index for individual ionophore compounds based on weight gain, feed conversion ratio, oocyst index, lesion score and mortality. Present studies revealed no resistance of the ionophores in any of the field isolates. Both the drugs showed varying degree of efficacy, e.g. maduramicin exhibited limited efficacy against all the three field isolates, whereas salinomycin showed limited efficacy against Gurgaon isolate (GrI)-I, good efficacy against GrI-II and partial resistance against GrI-III.

Animals↗
PubMed2001

Posterior fossa dermoid in association with Klippel-Feil syndrome--a short report.

A posterior fossa dermoid cyst in association with the Klippel-Feil syndrome, in a 4 year old child is reported. Early diagnosis to prevent complications like neural compression, cyst rupture and staphylococcal meningitis justifies investigation for posterior fossa dermoids in cases of Klippel-Feil syndrome. Their embryological basis is discussed.

Brain Neoplasms↗
PubMed2000

Posterior sagittal approach for repair of rectourethral fistula occurring after perineal surgery for imperforated anus at birth.

PURPOSE: Posterior sagittal approach was used for the repair of 11 cases of rectourethral fistula between 1992 and 1998. METHODS: All these patients had rectourethral fistula as a result of perineal procedure performed for imperforate anus at the time of birth. In addition to the fistula repair, an associated anorectal stenosis (3 cases) and urethral stricture 11 case) also were corrected with this approach. All the patients underwent surgery under cover of a protective colostomy. RESULTS: Successful repair was achieved in all patients, and the follow-up period ranged from 10 months to 7 years. As far as bladder and bowel control, urinary control was normal in all 11 patients, whereas bowel control was normal in 10 cases. One patient who had severe scarring of anal sphincters caused by infection in the previous surgery still suffers occasional perianal soiling after 18 months of follow-up. CONCLUSIONS: Posterior sagittal approach not only gives adequate exposure but also suits the basic principles of fistula repair, namely, completely separating the rectum from urethra and leaving normal rectal wall behind the urethral sutures thus eliminating the possibility of recurrence. In addition to fistula repair, one can also correct associated problems like anorectal stenosis or urethral stricture, and a mislocated rectum can be relocated within the sphincter complex.

Adult↗
PubMed1999

Glioblastoma multiforme in a mature ovarian teratoma with recurring brain tumours.

AIMS: We report a case study to highlight the occurrence of glioblastoma multiforme in an ovarian teratoma. METHODS AND RESULTS: A 10-year-old girl presented with a left frontal lobe primitive neuroectodermal tumour which was successfully treated. After 6 uneventful years, she developed glioblastoma multiforme located posterior to the site of the initial tumour. Six years later, she presented with a mature cystic teratoma containing glioblastoma multiforme. CONCLUSIONS: Glioblastoma in an ovarian teratoma is an exceptional event, which might have an initial clinical presentation as a metastatic brain tumour. Alternatively, recurring glial tumours may occur in a genetically predisposed person; the role of radiation and chemotherapy in this context remains to be elucidated.

Biomarkers, Tumor↗
PubMed1997

Clinical dysautonomia in diabetes mellitus--a study with seven autonomic reflex function tests.

Thirty-eight patients of NIDDM, 12 of IDDM and 10 healthy age matched controls were subjected to seven standardised autonomic reflex function tests. A scoring criteria was utilised for diagnosing and grading the severity of dysautonomia. Eight patients of IDDM and 24 of NIDDM had dysautonomia. One-third of the patients in each group had grade IV autonomic dysfunction. Severity of autonomic dysfunction was directly related to the duration of disease in NIDDM whereas in IDDM this relation was not seen. Peripheral neuropathy was almost always associated with dysautonomia in NIDDM. On the contrary, in IDDM dysautonomia was independent of peripheral neuropathy. Charcot's arthopathy, dysphagia, constipation and nocturnal diarrhea were always associated with evidence of dysautonomia. Other symptoms viz. gustatory sweating, postural dizziness and impotence did not necessarily indicate dysautonomia.

Adult↗
PubMed1997

An ab initio study of histamine agonists.

A systematic theoretical study on histamine agonists and their interaction with H1 and H2 receptor models has been carried out utilizing ab initio molecular orbital technique. The effect of substituents on histamine agonists' charge distribution and their agonistic activity has been studied in detail. Drug-receptor interaction models have been studied at the Hartree Fock level of theory with a split valence basis set keeping the cost and efficiency of the calculation in mind. The study indicates that the agonistic activity is controlled either by receptor conformation or by steric hinderances caused by the substituents. The monocationic form of histamine does not appear to be a necessity for a proton relay process which is similar to the one proposed earlier by Weinstein and coworkers. The study also indicates some importance of common cellular ions in neurotransmitter properties of histamine.

Histamine Agonists↗
PubMed1996

Comparison of biochemical parameters in pleural effusion.

A comparison of various biochemical parameters used in differentiation of nature of pleural effusion in transudate and exudate was done in 84 patient of pleural effusion. Pleural fluid (P) cholesterol and bilirubin which have gained an importance in recent years were compared with pleural fluid protein, LDH, P/S protein, P/S LDH and Light's criteria. It was seen that Light's criteria is still the best in differentiation. Sensitivity of individual test was nearly same for Pl. protein (94.11%), P/S Protein (94.11%), Pl. LDH (95.5%), P/S LDH (92.75%). Pl cholesterol (88.3%) and P/S cholesterol (91.42%) had slightly lower sensitivity. Pl. Protein and P/S LDH had 100% specificity. Lights criteria had 100% specificity and sensitivity % of cases misclassified by various criteria were Pl Protein 5.95%, P/S protein 5.95%, PLDH 4.76%, P/S LDH 4.76% P. Cholesterol 13% and P/S Cholesterol 9.52% Measurement of Bilirubin did not provide any correlation in classifying the effusion and thus did not hold any value.

Bilirubin↗
PubMed1993

Clean intermittent catheterisation for the neuropathic bladder.

Clean intermittent catheterisation (CIC) has been used as the effective method of bladder drainage in paraplegics for over a decade in our centre. In 27 acute spinal cord injury (SCI) patients managed by CIC from day one, symptomatic urinary infection occurred in 5 with a follow up period of 10 days to 3 months. No prophylactic/suppressive antibiotics were used. In 21 patients on long term CIC (1-12 years) symptomatic infections occurred during a 6 month follow up at a rate of 0.07 episodes per patient per month. Urine cultures proved positive in 26%. The types of bacteria and their sensitivity towards antibiotics were different in both groups.

Anti-Bacterial Agents↗