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P K Saha

Publications and source records attributed to P K Saha.

At least 19 recordsLinked to original sources
PubMed2006

Exclusive measurement of the nonmesonic weak decay of the lambda(5)He hypernucleus.

We performed a coincidence measurement of two nucleons emitted from the nonmesonic weak decay of lambda(5)He formed via the 6Li(pi+, K+) reaction. The energies of the two nucleons and the pair number distributions in the opening angle between them were measured. In both np and nn pairs, we observed a clean back-to-back correlation coming from the two-body weak reactions of lambda p --> np and lambda n --> nn, respectively. The ratio of the nucleon pair numbers was N(nn)/N(np) = 0.45 +/- 0.11(stat) +/- 0.03(syst) in the kinematic region of cos theta(NN) < -0.8. Since each decay mode was exclusively detected, the measured ratio should be close to the ratio of gamma(lambda p --> np)/gamma(lambda n --> nn). The ratio is consistent with recent theoretical calculations based on the heavy meson and/or direct-quark exchange picture.

Journal Article↗
PubMed2006

Structural MRI of carotid artery atherosclerotic lesion burden and characterization of hemispheric cerebral blood flow before and after carotid endarterectomy.

Collateral circulation plays a major role in maintaining cerebral blood flow (CBF) in patients with internal carotid artery (ICA) stenosis. CBF can remain normal despite severe ICA stenosis, making the benefit of carotid endarterectomy (CEA) or stenting difficult to assess. Before and after surgery, we assessed CBF supplied through the ipsilateral (stenotic) or contralateral ICA individually with a novel hemisphere-selective arterial spin-labeling (ASL) perfusion MR technique. We further explored the relationship between CBF and ICA obstruction ratio (OR) acquired with a multislice black-blood imaging sequence. For patients with unilateral ICA stenosis (n = 19), conventional bilateral labeling did not reveal interhemispheric differences. With unilateral labeling, CBF in the middle cerebral artery (MCA) territory on the surgical side from the ipsilateral supply (53.7 +/- 3.3 ml/100 g/min) was lower than CBF in the contralateral MCA territory from the contralateral supply (58.5 +/- 2.7 ml/100 g/min), although not statistically significant (p = 0.09). The ipsilateral MCA territory received significant (p = 0.02) contralateral supply (7.0 +/- 2.7 ml/100 g/min), while ipsilateral supply to the contralateral side was not reciprocated. After surgery (n = 11), ipsilateral supply to the MCA territory increased from 57.3 +/- 5.7 to 67.3 +/- 5.4 ml/100 g/min (p = 0.03), and contralateral supply to the ipsilateral MCA territory decreased. The best predictor of increased CBF on the side of surgery was normalized presurgical ipsilateral supply (r(2) = 0.62, p = 0.004). OR was less predictive of change, although the change in normalized contralateral supply was negatively correlated with OR(excess) (=OR(ipsilateral) - OR(contralateral)) (r(2) = 0.58, p = 0.006). The results demonstrate the effect of carotid artery stenosis on blood supply to the cerebral hemispheres, as well as the relative role of collateral pathways before surgery and redistribution of blood flow through these pathways after surgery. Unilateral ASL may better predict hemodynamic surgical outcome (measured by improved perfusion) than ICA OR.

Aged↗
PubMed2006

Predictors of development and outcome in patients with acute respiratory distress syndrome due to tuberculosis.

OBJECTIVE: To study the predictors of development and determinants of outcome in patients with acute respiratory distress syndrome (ARDS) due to tuberculosis (TB). METHODS: Retrospective case-control study of demographic, clinical and laboratory data of hospitalised adult patients with active TB. RESULTS: Of 2733 TB patients treated during 1980-2003, 29 (1.06%; 1.21 patients/year; mean age 31.6 +/- 10.9 years; 16 males) developed ARDS (cases). Seven had pulmonary TB and 22 had miliary TB (MTB); 298 (mean age 32.0 +/- 14.2 years; 110 males) who did not develop ARDS constituted controls. Presence of MTB (OR 4.6, 95%CI 1.2-17.8; P = 0.02), duration of illness beyond 30 days at presentation (OR 177.9, 95%CI 39-811.7; P < 0.001), absolute lymphocyte count < 1625/ mm3 (OR 4.5, 95%CI 1.1-19.3; P = 0.04) and serum ALT > 100 IU (OR 15.7, 95%CI 3.0-81.1, P < 0.001) were independent predictors of ARDS development. Twelve cases died (41.4%). Patients with APACHE II score >18; those with APACHE II score <18 in the presence of hyponatraemia and PaO2/FIO2 ratio <108.5 were likely to die. CONCLUSIONS: In patients with TB, prolonged illness, MTB, absolute lymphocytopaenia and elevated ALT are independently associated with ARDS development. APACHE II score, serum sodium and PaO2/FIO2 ratio are determinants of outcome.

Adult↗
PubMed2005

Leech bite: a rare gynecologic emergency.

Vaginal bleeding as the result of a leech bite is a rare occurrence. We report 2 cases of vaginal bleeding in young girls that resulted from a leech bite and required treatment. Clinical presentation and management for young girls is described. Health professionals working in rural areas where leech infestation is common should be aware that children are at risk for leech bites in the genital region; a high index of suspicion is of great help to make an early diagnosis and ensure prompt treatment.

Animals↗
PubMed2005

Production of the neutron-rich hypernucleus 10LambdaLi in the (pi-,K+) double charge-exchange reaction.

In order to produce a neutron-rich Lambda hypernucleus for the first time, we carried out an experiment by utilizing the (pi-,K+) double charge-exchange reaction on a 10B target. We observed the production of a 10LambdaLi hypernucleus. The cross section for the Lambda bound region was found to be 11.3+/-1.9 nb/sr with the 1.2 GeV/c incident momentum, which is compared with the 10LambdaB hypernucleus production cross section, 7.8+/-0.3 microb/sr, in the (pi+,K+) reaction with a 1.05 GeV/c incident momentum beam.

Journal Article↗
PubMed2005

Mechanics of the ankle and subtalar joints revealed through a 3D quasi-static stress MRI technique.

A technique to study the three-dimensional (3D) mechanical characteristics of the ankle and of the subtalar joints in vivo and in vitro is described. The technique uses an MR scanner compatible 3D positioning and loading linkage to load the hindfoot with precise loads while the foot is being scanned. 3D image processing algorithms are used to derive from the acquired MR images bone morphology, hindfoot architecture, and joint kinematics. The technique was employed to study these properties both in vitro and in vivo. The ankle and subtler joint motion and the changes in architecture produced in response to an inversion load and an anterior drawer load were evaluated. The technique was shown to provide reliable measures of bone morphology. The left-to-right variations in bone morphology were less than 5%. The left-to-right variations in unloaded hindfoot architecture parameters were less than 10%, and these properties were only slightly affected by inversion and anterior drawer loads. Inversion and anterior drawer loads produced motion both at the ankle and at the subtalar joint. In addition, high degree of coupling, primarily of internal rotation with inversion, was observed both at the ankle and at the subtalar joint. The in vitro motion produced in response to inversion and anterior drawer load was greater than the in vivo motion. Finally, external motion, measured directly across the ankle complex, produced in response to load was much greater than the bone movements measured through the 3D stress MRI technique indicating the significant effect of soft tissue and skin interference.

Adult↗
PubMed2005

Contraceptive practices and awareness of emergency contraception in educated working women.

BACKGROUND: Regular contraceptive use and emergency contraception are tools to prevent pregnancies. AIMS: This study was designed to investigate knowledge and use of contraceptive methods and awareness of emergency contraception among women working in the hospital. SETTINGS: Educated workingwomen in a medical college hospital. DESIGN: Cross-sectional study. MATERIALS AND METHODS: The study was carried out among women belonging to three categories: staff nurses, ministerial staff and others. Married as well as unmarried employees in the reproductive age group were interviewed. A pretested mixed questionnaire containing open as well as closed ended questions was administered. The women were asked questions concerning knowledge and use of contraceptive methods and awareness of emergency or postcoital contraception. RESULTS: Of the 284 employees 258 women consented for the interview. All the subjects were literate and majority (97.2%) had an urban background. Of the 190 married women, 154 (81.1%) practiced contraception, among them (73.3%) were regular users. Eighty respondents underwent abortions of which 46 had spontaneous and 34 had induced abortions. Among the available contraceptive methods, condom was the most popular method in 89 (57.8%) followed by Copper T in 38 women (24.7%). The use of hormonal contraception was very low 2.6%. Print and electronic media were the common source of public awareness in 149 subjects (57.7%). Twenty-nine women (11.2%) were aware and only three women used emergency contraception. CONCLUSIONS: A high percentage of females in this literate workingwomen population used contraception; however, the awareness of emergency contraception was low.

Adult↗
PubMed2005

Reversal of subclinical adrenal insufficiency through antituberculosis treatment in TB patients: a longitudinal follow up.

BACKGROUND & OBJECTIVE: Subclinical adrenal insufficiency has been shown to occur in patients with tuberculosis. Whether this insufficiency can be reversed with therapy and on long-term follow up, is not known. We studied the effect of antituberculosis treatment (ATT) with respect to reversal of the adrenal insufficiency, as assessed by response to standard dose adrenocorticotropin (ACTH) stimulation test in TB patients. METHODS: One hundred and five HIV-negative tuberculosis patients were studied. Of these, 72 patients had pulmonary and 33 had extrapulmonary forms of the disease. Baseline (pre-treatment) standard-dose ACTH stimulation test was done on all the subjects, following which, they were put on standard antituberculosis therapy, depending on the type of disease and were followed up for a period of 30 months. ACTH stimulation tests were performed at follow up, every 6 months. RESULTS: Baseline (pre-treatment) standard-dose ACTH stimulation test revealed an impaired response in 52 of 105 patients (49.5%). At 6 months, the percentage of responders had increased to 71 per cent with a gradual increasing trend noted thereafter. At 24 months, 31 of the 32 patients (97%) who were followed up demonstrated a normal response to ACTH stimulation. The percentage of responders was comparable in both pulmonary [21 of 22 patients (95%)] and extrapulmonary TB [10 of 10 patients (100%)] groups at follow up. INTERPRETATION & CONCLUSION: Our study shows that nearly half of patients with active tuberculosis had a subclinical adrenal insufficiency indicated by an impaired response to ACTH stimulation test. This insufficiency reverse with therapy in most patients on long-term follow up.

Adrenal Insufficiency↗
PubMed2004

Spectrum of clinical disease in a series of 135 hospitalised HIV-infected patients from north India.

BACKGROUND: Literature on the spectrum of opportunistic disease in human immunodeficiency virus (HIV)-infected patients from developing countries is sparse. The objective of this study was to document the spectrum and determine the frequency of various opportunistic infections (OIs) and non-infectious opportunistic diseases, in hospitalised HIV-infected patients from north India. METHODS: One hundred and thirty five consecutive, HIV-infected patients (age 34 +/- 10 years, females 17%) admitted to a tertiary care hospital in north India, for the evaluation and management of an OI or HIV-related disorder between January 2000 and July 2003, were studied. RESULTS: Fever (71%) and weight loss (65%) were the commonest presenting symptoms. Heterosexual transmission was the commonest mode of HIV-acquisition. Tuberculosis (TB) was the commonest OI (71%) followed by candidiasis (39.3%), Pneumocystis jiroveci pneumonia (PCP) (7.4%), cryptococcal meningitis and cerebral toxoplasmosis (3.7% each). Most of the cases of TB were disseminated (64%). Apart from other well-recognised OIs, two patients had visceral leishmaniasis. Two cases of HIV-associated lymphoma were encountered. CD4+ cell counts were done in 109 patients. Majority of the patients (82.6%) had CD4+ counts <200 cells/microL. Fifty patients (46%) had CD4+ counts <50 cells/microL. Only 50 patients (37%) received antiretroviral therapy. Twenty one patients (16%) died during hospital stay. All but one deaths were due to TB (16 patients; 76%) and PCP (4 patients; 19%). CONCLUSIONS: A wide spectrum of disease, including both OIs and non-infectious opportunistic diseases, is seen in hospitalised HIV-infected patients from north India. Tuberculosis remains the most common OI and is the commonest cause of death in these patients.

AIDS-Related Opportunistic Infections↗
PubMed2004

Reproducibility and error sources of micro-MRI-based trabecular bone structural parameters of the distal radius and tibia.

The mechanical competence of trabecular bone is significantly determined, next to material density, by its three-dimensional (3D) structure. Recent advances in micromagnetic resonance imaging (micro-MRI) acquisition and processing techniques allow the 3D trabecular structure to be analyzed in vivo at peripheral sites such as the distal radius and tibia. The practicality of micro-MRI-based noninvasive virtual bone biopsy (VBB) for longitudinal studies of patients hinges on the reproducibility of the derived structural parameters, which largely determine the size of the effect that can be detected at a given power and significance level. In this paper, the reproducibility of micro-MRI-derived trabecular bone structure measures was examined by performing repeat studies in six healthy subjects in whom the distal aspects of the radius and tibia were scanned with a 3D spin-echo sequence at 137 x 137 x 410 microm3 voxel size. Bone volume fraction (BV/TV) and digital topological analysis (DTA) structural parameters including the topological bone surface-to-curve ratio (SCR) and topological erosion index (TEI) were evaluated after subjecting the raw images to a cascade of processing steps. The average coefficient of variation was 4-7% and was comparable for the two anatomic sites and for all parameters measured. The reliability expressed in terms of the intraclass correlation coefficient ranged from 0.95 to 0.97 in the radius and 0.68 to 0.92 in the tibia. Error analysis based on simulations suggests involuntary patient motion, primarily rotation, to be the chief source of imprecision, followed by failure to accurately match the analysis volumes in repeat studies.

Adult↗
PubMed2003

Clinical and genetic risk factors for the development of multi-drug resistant tuberculosis in non-HIV infected patients at a tertiary care center in India: a case-control study.

Genetic susceptibility of the host to multi-drug resistant tuberculosis (MDR-TB) is not fully understood. We undertook a case-control study at a tertiary care center at New Delhi, India to identify the clinical and genetic predictors of MDR-TB as compared to the drug sensitive TB cases. Patients with multi-drug resistant tuberculosis were identified on the basis of drug sensitivity testing by the proportion method. Treatment was initiated according to standard norms and all patients were followed up during the period. Genomic DNA extracted from the peripheral blood mononuclear cell pellet was used for amplification of HLA class II region (second exon) with a set of forward (5') and reverse (3') primers. A sequence specific 5' biotinylated probes were used to determine 12 DRB1, 8 DQA1 and 13 DQB1 alleles by the PCR-SSOP method. Past history of disease, higher severity of illness, inadequacy of drug treatment and presence of HLA-DRB1*14, DQB1*0503 and DQB1*0502 alleles were found to be significant risk factors for MDR-TB. Multivariate analysis identified poor past compliance to treatment (odds ratio, OR=6.6; 95% confidence interval, CI [2.0-21.5]), higher number of cavities (OR=6; 95% CI [2.1-17.3]) in chest radiographs and the presence of the HLA-DRB1*14 allele (OR=8.2; 95% CI [2.1-31.3]) as independent predictors of MDR-TB. Our results suggest that a combination of clinical and immunogenetic parameters could provide better information on drug resistance in tuberculosis with implications in therapy.

Adult↗
PubMed2003

Increasing HIV seropositivity among adult tuberculosis patients in Delhi.

We report the HIV seropositivity among adult TB patients from our hospital, a tertiary care hospital in north India between 2000-2002. Of the 555 patients with various forms of tuberculosis, 52 were found to be seropositive (9.4%). In 1994-1999, the HIV seropositivity in this hospital was only 0.4 per cent (2 of 500 patients). This communication describes a dramatic increase in seropositivity and highlights the importance of continued HIV serosurveillance in patients with TB.

Adolescent↗
PubMed2002

Sigma-nucleus potential in A=28.

We have studied the (pi(-),K+) reaction on a silicon target to investigate the sigma-nucleus potential. The inclusive spectrum was measured at a beam momentum of 1.2 GeV/c with an energy resolution of 3.3 MeV (FWHM) by employing the superconducting kaon spectrometer system. The spectrum was compared with theoretical calculations within the framework of the distorted-wave impulse approximation, which demonstrates that a strongly repulsive sigma-nucleus potential with a nonzero size of the imaginary part reproduces the observed spectrum.

Journal Article↗
PubMed2001

Observation of a (6)(LambdaLambda)He double hypernucleus.

A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of ( 6)(LambdaLambda)He emitted from a Xi(-) hyperon nuclear capture at rest. The mass of ( 6)(LambdaLambda)He and the Lambda-Lambda interaction energy DeltaB(LambdaLambda) have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of DeltaB(LambdaLambda) is 1.01+/-0.20(+0.18)(-0.11) MeV. This demonstrates that the Lambda-Lambda interaction is weakly attractive.

Journal Article↗