Biomedical subjects
S Saha
Publications and source records attributed to S Saha.
Viability of bovine blastocysts obtained after 7, 8 or 9 days of culture in vitro following vitrification and one-step rehydration.
This study examined morphological appearance, viability and hatching rates in relation to the total cell number following vitrification of in vitro produced bovine blastocysts and expanded blastocysts. In Experiment 1, embryos obtained after 7, 8 or 9 d of culture were pooled and equilibrated in either 10% ethylene glycol (EG) or 10% EG plus 0.3M trehalose in Dulbecco's phosphate buffered saline (DPBS) supplemented with 10% calf serum and 0.6% BSA for 5 min each, at room temperature, and then vitrified together in precooled vitrification solutions consisting of 40% EG (Treatment 1), 40% EG plus 0.3M trehalose (Treatment 2), 40% EG plus 0.3M trehalose and 20% polyvinylpyrrolidone (PVP, Treatment 3) in DPBS. The embryo viability and hatching rates of Treatment 1 (19 and 3%) differed significantly (P < 0.05) from those of Treatment 2 (56 and 31%) and Treatment 3 (70 and 43%). There was a significant difference (P < 0.05) in embryo viability between Treatment 2 (31%) and Treatment 3 (43%). In Experiment 2, Day 7, 8 and 9 embryos were vitrified separately, with higher viability and hatching rates in Experiment 1 than in Experiment 2. The viabilities of Day 7 (87%), 8 (71%) and 9 (46%) embryos differed significantly (P < 0.05). Again, there were significant differences (P < 0.01) among the hatching rates of Day 7 (75%), 8 (38%) and 9 (9%) embryos. The total cell number of hatched blastocysts was then determined by differential fluorochrome staining. The total cell number of Day 7, 8 and 9 embryos differed significantly (P < 0.05).
Metacarpal fracture fixation with absorbable polyglycolide rods and stainless steel K wires: a biomechanical comparison.
Self-reinforced polyglycolide (SR-PGA) rods have been used widely for fracture fixation as an alternative to metallic implants. However, because of its insufficient strength and strength retention, the use of SR-PGA has been restricted to fractures or osteotomies of low stress bearing cancellous bone. To investigate its usefulness in fixing the fractures of cortical bone, the mechanical strength of a human metacarpal fracture fixed with SR-PGA rods was evaluated. The surgical constructs were immersed in buffered saline solution and maintained at body temperature (37 degrees C). The mean initial bending stiffness of the specimens fixed with the SR-PGA rods was 61% of that of the specimens fixed with Kirschner wires. The bending stiffness of the specimens fixed with the SR-PGA rods decreased gradually, and most of the specimens lost their mechanical stability when immersed for 4 weeks. When SR-PGA rods are used to fix the fracture of human cortical bone, such as diaphyseal fracture of the metacarpal bone, it should be protected by additional means.
ECG compression by multirate processing of beats.
This paper presents a new compression scheme for single channel ECG, by delineating each ECG cycle. It uses multirate processing to normalize the varying period beats, followed by amplitude normalization. These beats are coded using vector quantization, with each beat being treated as a vector of uniform dimension. The average amplitude scale factor and the average beat period are made available at the decoder, along with the codebook of period and amplitude normalized beat vectors, to facilitate reconstruction of the signal. The actual beat period and the actual maximum amplitude of the beat are sent to the decoder by DPCM. It achieves a high quality approximation at less than 30 bits per second, with a compression ratio of around 100:1 to 200:1. To assess the technique properly we have evaluated two measures of error. Finally, the merits and demerits of the technique are discussed.
Normal calves obtained after direct transfer of vitrified bovine embryos using ethylene glycol, trehalose, and polyvinylpyrrolidone.
In the present study, IVF bovine embryos were vitrified using as the cryoprotectants, ethylene glycol plus trehalose plus the polymer, polyvinylpyrrolidone (PVP). In Experiment I, toxicity of the vitrification solution (VS) containing 20% PVP was tested in relation to temperature and exposure time. One hundred percent embryo development was observed with treatment at 5 degrees C for 5 min, whereas only 55.5% embryos were developed when the treatment was carried out at 20 degrees C for 5 min. In Experiment II, embryos were vitrified using one of the three treatments (Treatment A, 40% ethylene glycol (EG); treatment B, 40% EG + 11.3% trehalose; and treatment C, 40% EG + 11.3% trehalose + 20% PVP and rehydrations) was performed directly in mPBS. Highest development (84.1%) and hatching rate (68.2%) were obtained when embryos were vitrified with the vitrification solution used in treatment C. In Experiment III, embryos were vitrified as in Experiment II (treatment C). The development and hatching rates were compared after rehydration in different rehydration solutions. No significant difference was observed among the development and hatching rates when rehydration was carried out in different concentrations of trehalose. Five vitrified-warmed bovine embryos were transferred directly to five recipients and three recipients gave birth to three normal calves.
Fertilization and development of frozen-thawed germinal vesicle bovine oocytes by a one-step dilution method in vitro.
The objective of this study was to evaluate in vitro fertilization and cleavage rates of frozen-thawed bovine oocytes at the germinal vesicle (GV) stage. In mouse oocytes, spindle microtubule reorganization after GV breakdown is particularly sensitive to cold and readily damaged by exposure to low temperatures, the damage becoming apparent only at the time of the first mitotic division. The effects of various permeating cryoprotective agents [1.8 M ethylene glycol (EG), 1.3 M ethylene glycol monomethyl ether (EME), and 1.6 M 1,2-propanediol (PROH)] and different concentrations of trehalose (T) and polyvinylpyrrolidone (PVP) on post-thaw developmental capacity were examined. When bovine GV oocytes were frozen slowly in mixtures of 1.8 M EG plus 5% PVP and 0.05 M T, almost 80% developed to metaphase II; 22.2% degenerated after in vitro maturation, and none of those that had been cryopreserved underwent parthenogenetic activation. The total fertilization rate was higher (P < 0.05) for oocytes frozen in a mixture of 1.8 M EG plus 0.05 M T or 0.1 M T than in a mixture of 1.8 M EG with or without 0.2 M T; however, there was no difference in the number of normally fertilized or polyspermic oocytes that had been frozen in various cryoprotective solutions. No significant difference was observed in subsequent development using EG, EME, and PROH for GV oocytes. The addition of 0.05 or 0.1 M trehalose to the freezing solution yielded significantly better cleavage and blastocyst rates than the solutions containing 0.2 M or no trehalose. For unfrozen controls, GV oocytes yielded significantly higher (P < 0.01) cleavage and blastocyst rates compared with frozen-thawed GV oocytes. It was found that 5% PVP had a beneficial effect compared with 10 or 20% concentrations for the development of blastocysts. Transfer of six blastocysts derived from frozen-thawed GV oocytes into three recipient heifers resulted in three pregnancies and the birth of one set of twins and one singleton calf.
Aflatoxin B1 contamination in groundnut samples collected from different geographical regions of India: a multicentre study.
Under a multicentre study conducted by the Indian Council of Medical Research, 2062 samples of groundnut were collected from rural and urban areas of 11 states representing different geographical regions of the country. These samples were analysed for aflatoxin B1 using the AOAC method. Analytical quality assurance between various participating laboratories was ensured through analysis of check-samples. Twenty-one per cent of groundnut samples collected from 11 states exceeded the permissible Indian regulatory limit of 30 micrograms/kg. No statistically significant difference in percentage of samples contaminated (> 30 micrograms/kg) were observed between pooled rural (22.9%) and urban (19.9%) data. Amongst the 11 states, the minimum and maximum per cent contamination respectively (> 30 micrograms/kg) was observed to be 15.2 in the state of Andhra Pradesh and 28.3 in the state of Haryana. The maximum level of contamination of 833 micrograms/kg was observed in the state of Gujarat. The median level of < 5 micrograms/kg was observed in the states of Gujarat, Haryana, Punjab, Andhra Pradesh and Karnataka. In all other states studied, the median level was found to vary between 10 and 20 micrograms/kg. The 90th percentile values were high in Andhra Pradesh (125 micrograms/kg), Gujarat (111 micrograms/kg) and Haryana (110 micrograms/kg). In the remaining states the 90th percentile value ranged from 60 to 93 micrograms/kg. Analysis of pooled data showed the percentages of samples exceeding the level of contamination of 5 micrograms/kg and 15 micrograms/kg, respectively were 44.9% and 37.4% which therefore, showed a marked increase when compared with the per cent of samples exceeding 30 micrograms/kg in the overall data.
Effect of HA coating on the long-term survival of dental implant: a review of the literature.
Hydroxyapatite (HA)-coated dental implants have been used clinically for over ten years. Several types of HA-coated implants are available commercially, and a number of clinical and basic studies evaluating the effect of HA coating have been reported. Concerns regarding microbiological susceptibility, resorption, fatigue, and Fracture in long-term application have been pointed out. However, in spite of the aggressive use of HA-coated implants for compromising cases, high success rates have been reported. Our review of the literature suggests that the advantages of using HA-coated dental implants are early bone response and a higher interface shear strength with bone.
External tibial torsion: an underrecognized cause of recurrent patellar dislocation.
Seventeen patients (18 knees) with recurrent patellar dislocation were identified with increased quadriceps angles secondary to excessive isolated external tibial torsion. Traditional realignment procedures attempted in these knees were unsuccessful because of failure to align the biomechanical axis of the extensor mechanism. Derotational osteotomies of the tibia just proximal to the patella tendon insertion were used to reduce the quadriceps angle to within normal limits to improve the biomechanics of the extensor mechanism. Seventeen (94%) knees were available for clinical and subjective followup at an average of 25 months (range, 1-3.2 years). Overall, 13 of the 17 knees were graded as good to excellent (76%). Five of the 17 patients also had well established anterior knee pain in addition to recurrent dislocation and were treated with a combined derotational and Maquet type osteotomy, with 4 patients obtaining a good to excellent result. Knees that subjectively and functionally demonstrated less painful symptoms preoperatively were associated with excellent results. Poor outcomes were associated with knees that were operated on multiple times.
Bronchogenic carcinoma in young adults.
Clinicopathological features of 26 cases of bronchogenic carcinoma in patients below the age of 40 years have been studied and compared with 271 cases of bronchogenic carcinoma occurring in elderly patients. There was female preponderance (19.23%) in the younger study group compared to the elderly group (6.6%) and increased incidence of smokers in the younger group (57.6% versus 79.3%) and had achieved statistical significance (p < 0.001). Majority (20 out of 26) had a rural background. All the patients were symptomatic at the time of diagnosis and all the 26 cases except one belonged to advanced stage. The incidence of squamous cell carcinoma was almost same for both the age groups. Eighteen of the 26 cases had received antituberculosis chemotherapy by general practitioners before referral to the specialists. Twenty patients were treated initially by palliative radiotherapy and then by chemotherapy.
Cervical fibroid with menorrhagia.
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Effect of noise stress on some cardiovascular parameters and audiovisual reaction time.
A study of the effect of noise stress on some of the physiological parameters was carried out on healthy male workers of thermal power station (exposed to sound level 90-113 dBA) and compared with age and sex matched healthy controls (exposed to sound level 48-66 dBA). The parameters recorded were heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), galvanic skin resistance (GSR), auditory and visual reaction time (ART and VRT) and audiogram. Significant impairment in audiogram at 3000 Hz and 4000 Hz, increase in HR, SBP, DBP and decrease in GSR, ART and VRT were recorded in workers who were exposed to noise stress. Also a higher prevalence of hypertension was observed in them and that they were at a higher risk of developing hypertension than the control group. It was also observed that these modifications are related to duration of exposure to noise stress. It is presumed that all the above extra auditory effects are due to activation of autonomic nervous system and hypothalamo-hypophyseal adrenal axis, and the resultant release of catecholamines from adrenal medulla due to noise stress.
Myelofibrosis secondary to SLE and its reversal on steroid therapy.
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Use of polymerase chain reaction in analysing recombinant cDNA clones encoding storage proteins of chickpea Cicer arietinum L.
A simple and reliable method was undertaken for the use of polymerase chain reaction in analyzing cDNA clones. Amplification was done of the inserts from positive legumin clones isolated from a cDNA library constructed from developing chickpea cotyledons in the expression vector, gt11. Amplification was made simple by using oligonucleotide primers which allowed convenient sizing, subcloning and sequencing of inserts by di-deoxy chain termination method. This simple method may provide opportunity to isolate large number of agronomically important genes from gene libraries.
Private sector volunteerism as a solution to caring for the uninsured.
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ATP hydrolysis is required for DNA cleavage by EcoPI restriction enzyme.
The type III restriction endonuclease EcoPI, coded by bacteriophage P1, cleaves unmodified DNA in the presence of ATP and magnesium ions. We show that purified EcoPI restriction enzyme fails to cleave DNA in the presence of non-hydrolyzable ATP analogs. More importantly, this study demonstrates that EcoPI restriction enzyme has an inherent ATPase activity, and ATP hydrolysis is necessary for DNA cleavage. Furthermore, we show that the progress curve of the reaction with EcoPI restriction enzyme exhibits a lag which is dependent on the enzyme concentration. Kinetic analysis of the progress curves of the reaction suggest slow transitions that can occur during the reaction, characteristic of hysteretic enzymes. The role of ATP in the cleavage mechanism of type III restriction enzymes is discussed.
Glucose promotes turnover of Na+ in pancreatic beta-cells.
Ouabain-induced changes of the free cytoplasmic Na+ concentration ([Na+]i) were monitored in aggregates of cells prepared from beta-cell-rich pancreatic mouse islets and the results were compared with the total islet content of sodium. The steady-state [Na+]i was lower in 20 mM glucose (11 mM) than in 3 mM glucose (14 mM). In the presence of 3 mM glucose the addition of 1 mM ouabain resulted in a rise in [Na+]i with an initial rate of 1.5 mM/min. However, the increase of total sodium corresponded to 2.8 mM/min, suggesting that rapid binding and/or sequestration of Na+ are prominent features for pancreatic beta-cells. Elevation of the glucose concentration to 20 mM increased the rate of ouabain-dependent rise of [Na+]i. The effect of glucose was mimicked by 1 mM tolbutamide or 100 microM carbachol and was counteracted by 100 nM of the alpha 2-adrenergic agonist clonidine. Glucose also accelerated the lowering of [Na+]i after withdrawal of ouabain. In promoting not only the entry but also the extrusion of Na+, glucose actually enhances the turnover of the ion in pancreatic beta-cells.
Comparison of the electrical and dielectric behavior of wet human cortical and cancellous bone tissue from the distal tibia.
We compared the electrical and dielectric properties of wet human cortical and cancellous bone tissue from the distal tibia. The relationships between the electrical and dielectric behavior of cortical and cancellous bone and variables of measurement such as frequency and direction (orientation) were evaluated. In general, the resistivity of human cortical bone was found to be approximately 3.1 times more than that of cancellous bone in the longitudinal direction and least 25 times more in the transverse directions. The dielectric permittivity of human cortical bone was approximately 3.9 times that of cancellous bone in the longitudinal direction, whereas in the transverse directions it was about 0.65 times greater. Measurement variables such as frequency and orientation appeared to affect cancellous and cortical bone differently. Strong correlations were found between the electrical properties in one direction and the electrical properties in the other two directions; however, these relationships differed for the samples of cortical and cancellous bone.