Ultimobranchial gland of freshwater catfish, Heteropneustes fossilis in response to deltamethrin treatment.
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Adaptation, Physiological↗
Biomedical subjects
S Srivastav
Publications and source records attributed to S Srivastav.
Quantitative ultrasound of the tibia depends on both cortical density and thickness.
This study investigated whether tibial speed of sound (SOS; SoundScan 2000, Myriad Ultrasound Systems, Israel) reflects not only bone mineral density (BMD) but also tibial cortical thickness, as assessed by dual-energy X-ray absorptiometry (DXA) and Quantitative CT (QCT) at a site-matched location. The secondary focus of the study was how tibial SOS compares with BMD at the spine and the hip, the most widely used locations for densitometry. Twenty-two young normal (N) and 23 postmenopausal women with spinal fractures (Fx) (mean (SD) age 35 (8) and 70 (5) years) underwent quantitative ultrasound (QUS) SOS measurement at the left tibial midshaft. From site-matched QCT scans (three 3-mm slices spaced along the QUS measurement region), BMD and cortical thickness were computed (QCT-cBMD, QCT-cTh). The cortex in the CT images was then subdivided into three concentric and equally spaced bands, and QCT-cBMD was computed separately for each band. DXA was performed at the mid-tibia (TIB BMD), at the spine (SPINE BMD) and the hip (total hip, HIP BMD). Correlation coefficients between parameters were determined with least-square linear fits. Intergroup differences were assessed by analysis of covariance, whose r2 value reflects the percentage variation in the data explained by group assignment. SOS correlated significantly with site-matched parameters (QCT-cBMD, OCT-cTh and TIB BMD, all r = 0.6, p < 0.001), SPINE BMD and HIP BMD (both r = 0.5, p < 0.001). Multiple regression with both QCT-cBMD and QCT-cTh against SOS yielded r = 0.7 with both parameters contributing significantly. For the cortex band subdivision, SOS correlated better with QCT-cBMD in the outermost band of the cortex (r = 0.67) than with the more central bands (r = 0.59 and r = 0.53). Group assignment could best explain SPINE BMD (r2 = 0.62) and HIP BMD (r2 = 0.51). SOS was comparable to TIB BMD (r2 = 0.3 vs. r2 = 0.35).: Our findings suggest that the tibial SOS measurement depends on both the thickness and density of the tibia, but is more strongly influenced by the density of the cortex near the surface than by its interior parts. The power of tibial ultrasound to discriminate between normal and fracture patients was less than that of spinal and femoral DXA BMD and comparable to site-matched DXA BMD.
Absorptiometry, Photon↗
MR imaging of the wrist in rheumatoid arthritis using gadobenate dimeglumine.
OBJECTIVE: To determine the dosage of gadobenate dimeglumine (Gd-BOPTA) necessary for MRI of rheumatoid arthritis of the wrist. DESIGN AND PATIENTS: Seven wrists inflamed with rheumatoid arthritis were imaged using a dedicated 0.2-T MR unit. Four cumulative dosages of 0.0125, 0.025, 0.05 and 0.1 mmol/kg body weight (BW) Gd-BOPTA were tested. Three-dimensional T1-weighted gradient-recalled echo sequences (GRE; TR: 100 ms, TE: 18 ms, flip angle 90 degrees , 4:55 min) were acquired prior to an intravenous injection and after each additional dosage of Gd-BOPTA. Relative enhancement, signal-difference-to-noise ratios (SDNRs) and the size of the inflamed tissue were quantified. Three radiologists independently evaluated the image quality, the size and the contrast of the enhancing tissue. RESULTS: The readers agreed on a dose of 0.05 mmol/kg BW as satisfactory for the evaluation of the size of the inflammatory tissue and for determination of bone involvement (kappa = 0.9, P < 0.001). Highly inflammatory pannus was depicted with adequate image contrast using 0.025 mmol/kg BW Gd-BOPTA. According to the SDNR and relative enhancement findings, a dose of 0.05 mmol/kg BW suffices for both off-center and centered regions of tissue inflammation (t-test, P < 0.05). CONCLUSION: Gadolinium-BOPTA is an alternative contrast agent for MRI of rheumatoid disease. This study shows that a dose of 0.05 mmol/kg BW suffices at low field strength.
Adult↗
Removal of copper by Pseudomonas putida strain S4 isolated from copper mines.
A bacterial strain, Pseudomonas putida S4, was isolated from smelter drainage of copper mines. The strain exhibited resistance to several heavy metals, like aluminium (Al), zinc (Zn), nickel (Ni), cobalt (Co) besides copper (Cu). Strain S4 could accumulate Cu from the Cu-supplemented growth medium. In the present study, we have demonstrated the Cu2+ removal capacity of this strain from various samples such as mine effluent, low-grade ore and ore-tailings, collected from the mining site. Moreover, approximately 80% of the accumulated Cu2+ could be recovered from the loaded biomass by a simple desorption procedure.
Biodegradation, Environmental↗
Backside nonconformity and locking restraints affect liner/shell load transfer mechanisms and relative motion in modular acetabular components for total hip replacement.
Nonconformity between the polyethylene liner and the metal shell may exist in modular acetabular components by design, due to manufacturing tolerances, or from locking mechanisms that attach the polyethylene liner to the metal shell. Relative motion at the liner/shell interface has been associated with backside wear, which may contribute to osteolysis which has been clinically observed near screw holes. The purpose of this study was to investigate the effect of nonconformity and locking restraints on the liner/shell relative motion and load transfer mechanisms in a commercially available, metal-backed acetabular component with a polar fenestration. The finite element method was used to explore the hypothesis that backside nonconformity and locking restraints play important roles in long-term surface damage mechanisms that are unique to modular components, such as backside wear and liner extrusion through screw holes. The three-body quasi-static contact problem was solved using a commercially available explicit finite element code, which modeled contact between the femoral head, polyethylene liner, and the metal shell. Four sets of liner boundary conditions were investigated: no restraints, rim restraints, equatorial restraints, and both rim and equatorial restraints. The finite element model with a conforming shell predicted between 8.5 and 12.8 microm of incremental extrusion of the polyethylene through the polar fenestration, consistent with in vitro experiments of the same design under identical loading conditions. Furthermore, idealized rim and/or equatorial liner restraints were found to share up to 71% of the load across the liner/shell interface. Consequently, the results of this study demonstrate that backside nonconformity and locking restraints substantially influence backside relative motion as well as load transfer at the liner/shell interface.
Acetabulum↗
Validation of a small punch testing technique to characterize the mechanical behaviour of ultra-high-molecular-weight polyethylene.
The small punch or miniaturized disc bend test has been used successfully to characterize the ductility and fracture resistance of metals and ceramics with specimens measuring 0.5 mm in thickness. This study was performed to demonstrate the feasibility of performing small punch tests on implant grade ultra-high-molecular-weight polyethylene (UHMWPE). Large-deformation finite element simulations were developed and validated to explore the hypothesis that the macroscopic constitutive behaviour of UHMWPE may be inferred from a miniature specimen testing technique which can be used to characterize the ductility and work to failure for UHMWPE. The load-displacement curve was insensitive to cyclic preconditioning of the test specimen and only mildly sensitive to the loading rate. Furthermore, the initial slope of the small punch load-displacement curve was used to determine the elastic modulus of the UHMWPE with the help of the inverse finite element method. The ultimate goal of this research is to develop the capability to perform local measurements of material tensile and static fracture properties in as-manufactured, as-sterilized and as-retrieved UHMWPE components.
Biocompatible Materials↗
Magnesium and antioxidant vitamin status and risk of complications of ageing in an elderly urban population.
This cross-sectional survey was conducted in 20 randomly selected streets in Moradbad city in North India to determine the association of magnesium and antioxidant vitamins with risk of ageing. There were 595 subjects (314 males, 281 females) between 50-84 years of age inclusive. The overall prevalence of hypo-magnesemia was 11.8 per cent (n = 60) with a prevalence of 13.2 per cent (n = 33) in males and 10.6 per cent (n = 27) in females. The prevalence of hypomagnesemia showed significant declining trend in the concentration of serum magnesium, vitamin C, vitamin E and beta-carotene and a rising trend in lipid peroxides and diene conjugates with increase in age from 50-59 years to 70-84 years in both men and women. Multivariate logistic regression analysis showed that serum magnesium, vitamin C, vitamin E and beta-carotene were significant risk factors of ageing in both men and women. The findings suggest that some urban populations of India can benefit by consuming higher dietary magnesium, potassium and antioxidant vitamins for prevention of ageing.
Aged↗
Epidemiological study of coronary artery disease and its risk factors in an elderly urban population of north India.
OBJECTIVE: In view of the rapid increase in the prevalence of coronary artery disease (CAD) in developing countries, our aim was to determine the prevalence of CAD and its risk factors and lifestyle factors in an elderly population from north India. METHODS: A random sample of 595 elderly subjects between 50 to 84 years of age was obtained from the urban population of Moradabad. The response rate was 90.1%. The survey methods included a questionnaire containing information on 7-day food intake, other lifestyle factors, Rose questionnaire for diagnosis of angina pectoris, a standard 12-lead electrocardiogram, blood pressure measurements and blood examination. RESULTS: The total prevalence of CAD based on clinical history and electrocardiogram was 121/1000 (95% CI 72 to 165). The prevalence rate was slightly higher in males (130/1000) than in females (110/1000). The prevalence of CAD based on the Rose questionnaire was 57/1000 and based on electrocardiogram in 561 asymptomatic subjects was 67/1000. CAD was significantly higher in the elderly (65 to 84 years) group than in the middle-aged (50 to 64 years) group (168 vs. 97 per 1000), respectively. While the prevalence of hypertension was significantly higher in the elderly than middle-aged group respectively (214 vs. 168 per 1000), the prevalence of central obesity was significantly higher in the middle-aged than elderly group (674 vs. 632 per 1000). Other risk factors including smoking were comparable in the two subgroups. Prevalence of major risk factors and central obesity were significantly higher among patients with CAD than in the rest of the subjects. Prevalence of CAD was significantly higher in the middle and higher socio-economic groups compared to the lower income group. These higher income groups were also eating significantly higher amounts of visible fat and had a higher prevalence of physical inactivity (93.3%) compared to the lower income group. CONCLUSIONS: CAD and its risk factors such as hypertension, hypercholesterolemia, diabetes and central obesity are of sufficient magnitude in the elderly population of India to be a major public health problem. The findings also indicate that CAD is more commonly associated with middle and higher socio-economic status which may be due to greater consumption of dietary fat and more sedentariness compared to lower socioeconomic groups.
Aged↗
Stimulation of neutrophil respiratory burst and degranulation by Japanese encephalitis virus-induced macrophage derived factor.
The effects of Japanese encephalitis virus (JEV) and JEV-induced macrophage derived neutrophil chemotactic factor (MDF) on respiratory burst and granule exocytosis in neutrophils were studied and were compared with N-formyl-methionyl-leucyl-phenylalanine (FMLP). JEV-stimulated neutrophils released reactive oxygen metabolites with maximum activity between days 7 and 9. The response in mice was sensitive to anti-JEV-antisera treatment. Stimulation by MDF resulted in quick release of superoxide and granule enzymes from neutrophils upon both in-vivo and in-vitro stimulation in a dose dependent manner. The effect was abrogated by the MDF-specific antisera treatment. These responses were similar in kinetics and magnitude to those produced in response to FMLP. The respiratory burst elicited by MDF was abrogated by staurosporine, indicating that neutrophil activation and signal transduction by MDF and FMLP are dependent on protein kinase C.
Alkaloids↗
Carpal tunnel syndrome: assessment by turbo spin echo, spin echo, and magnetization transfer imaging applied in a low-field MR system.
PURPOSE: The purpose of this work was to evaluate patients with carpal tunnel syndrome (CTS) using a low-field extremity MR system (E-MRI: 0.2 T). METHOD: Twenty-two patients with typical findings of CTS and 30 control persons were imaged on an E-MRI. Axial T2-weighted turbo SE (TSE), T1-weighted SE sequences, and 2D GRE magnetization transfer (MTC) sequences were compared. SE and MTC sequences were obtained before and after contrast agent administration (0.1 mmol/kg body wt of Gd-DTPA). Two readers evaluated typical MR findings of CTS independently. RESULTS: Patients with CTS demonstrated palmar bowing of the flexor retinaculum significantly more often. The normal or edematous median nerve was best identified on TSE and MTC scans (kappa = 0.59 and 0.8). The MTC sequences showed perineural enhancement significantly better than respective T1-weighted SE sequences but were rated second in comparison with T2-weighted TSE scans. CONCLUSION: At low-field strength, median nerve edema is best depicted on T2-weighted TSE sequences, whereas MTC sequences are most sensitive to perineural contrast enhancement.
Carpal Tunnel Syndrome↗
Serial echocardiography in transplanted heart: an initial report of five cases.
Role of echocardiography including Doppler is established in selection of donor and in the care of patients after cardiac transplantation. Its value for recognition of transplant rejection is however still evolving. We present here, serial echocardiographic findings in five male patients, aged 22 to 46 years who underwent cardiac transplantation at our institution. There was no appreciable change on follow-up in the left ventricular dimensions, thickness of left ventricular posterior wall and interventricular septum and left ventricular systolic function. Transient pericardial effusion was noted in two patients. Trivial to mild mitral and tricuspid regurgitation was observed. The diastolic function of the left ventricle, as assessed by mitral valve inflow wave pattern, was normal in four patients. However in the fifth patient, there was evidence of diastolic dysfunction of the left ventricle and this change was accompanied by rejection episode (IIIB changes) in the endomyocardial biopsy. With resolution of rejection in biopsy, the diastolic function by Doppler also returned to normal. We conclude that echocardiography has a definite role in the general care of patients after cardiac transplantation. Transient small pericardial effusion and mild atrioventricular valve regurgitation are common after the operation. Echocardiography may also be of use in recognition of rejection episode by demonstrating evidence of diastolic dysfunction of the left ventricle. Currently, endomyocardial biopsy remains the gold standard for diagnosis of rejection.
Adult↗