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Biomedical subjects

R C Sharma

Publications and source records attributed to R C Sharma.

At least 19 recordsLinked to original sources
PubMed2003

Sperm motion characteristics of Garole rams raised for a prolonged period in a semi-arid tropical environment.

The Garole is a prolific but less well known and rare breed of small sheep found in the hot and humid Sunderban region of West Bengal. An ability to breed throughout the year and to graze in knee-deep water, resistance to foot rot and a strong mothering instinct are some of the special features of this breed. Garole rams could provide germplasm to incorporate prolificacy traits by artificial insemination of the nonprolific sheep breeds found in abundance in the semi-arid and arid tropical climates of India. The aim of the present study was to evaluate the semen production by Garole rams maintained in a semi-arid climate for three years and to objectively assess their semen quality by a computer-assisted sperm analysis technique. The donor rams were randomly selected each year from the original flock procured from their natural habitat or from the offspring born at the Institute farm. Semen was collected weekly for three weeks each autumn for three consecutive years from 8 rams each year. The overall means (SD) of the traits that did not differ significantly with age or year were volume, concentration, curvilinear velocity, average path velocity, amplitude of lateral head displacement, beat frequency, motility and the percentages of rapid motile sperms and of slow motile sperms. The age of the rams had a significant effect (p<0.05) on the straight-line velocity but this was not significantly affected by the length of exposure to the semi-arid climate. However, the age and year had significant effects (p<0.05) on linearity, straightness and the percentage of medium motile sperms. It was concluded that Garole rams are capable of producing good-quality semen even after a prolonged period of exposure to a semi-arid tropical climate.

Animals↗
PubMed2003

Assessing skull burdens of actinides using a mathematical phantom: a Monte Carlo approach.

In vivo monitoring techniques are needed to estimate the amount of an actinide in the skeleton in addition to that in the lungs and liver. Skull counting with external detectors has been a standard procedure for this purpose. Realistic skull phantoms are normally used to calibrate the counting systems. However, the fabrication of realistic phantoms is extremely difficult and expensive. Therefore, a theoretical approach based on Monte Carlo methods in conjunction with a Cristy mathematical phantom has been examined for assessing skull burdens of actinides. A computer program that generates surface sources of actinides on the skull and simulates low-energy photon transport in the heterogeneous media of the head region of the Cristy phantom was developed for this purpose. The program determines the observable pulse height spectrum of the detector and the corresponding calibration factors for different counting geometries. The computer program was used to generate the pulse height spectra and the corresponding calibration factors of 20 cm and 15 cm diameter phoswich detectors, each positioned on the left and right sides and on the top of the head region of the Cristy phantom, whose skull surfaces were assumed to have a uniform distribution of 241Am. The computed calibration factor for a counting geometry consisting of three phoswich detectors (15 cm diameter each) surrounding the phantom's skull was found to be in excellent agreement with the experimental results obtained for the same geometry using a realistic physical skull phantom. This provided a validation of the realistic design of the skull in the Cristy phantom, implying that the results reported in this paper could be used for in vivo measurements of skull burdens of 241Am for the stated counting geometry.

Actinoid Series Elements↗
PubMed2003

Long term lung retention studies of 125Sb aerosols in humans.

This paper describes the retention of 125Sb oxide aerosols in human lungs based on the data obtained from a group of seven accidental inhalation exposure cases. Long-term follow-up studies for periods of time ranging from 1 to 3 d post intake to 199 to 2,422 d post intake have indicated the biological lung clearance half-time of this material ranging from about 600 to 1,100 d for non-smokers and 1,700 to 3,700 d for smokers. The retention in the lungs after 180 d in all the seven cases is found to be much more than 51% of the estimated initial alveolar deposit, which is consistent with the present ICRP criteria of assignment to the lung absorption Type S. There is little previously reported human data on this radionuclide compound. In these studies reliable information on actual time of intake, the likely type of material, and the amount of retained body/lung activity in initial days after the incident was also available, which adds to the importance of these data. The results of these studies provide a basis for firm classification and suggest that oxides of antimony need to be removed from absorption Type M (earlier class W) where these are presently listed by ICRP and be placed in absorption Type S (earlier class Y). The range of measured retained lung activities after the initial rapid clearance phase (7 d post exposure) was about 3 to 14 kBq, which was sufficient for long-term follow up studies using the whole body counters.

Adult↗
PubMed2002

Development of an automated shielded chair whole-body monitor.

A standard shielded chair whole-body monitor has been developed as a computer controlled, unattended, walk-in-type of whole-body monitor for internal dosimetry of radiation workers. A radiation worker enters his personal computer code through the attached computer terminal and follows a few instructions on the screen. The chair door then opens automatically and after the worker has positioned himself into the counting geometry in the chair, the door closes. At the end of the whole-body monitoring for a pre-set time, the chair door opens again and the worker moves out. The monitoring data acquired on a 4K-MCA is saved in the computer memory automatically and the chair door closes again making it available for monitoring the next worker. The system also gives audio instructions to the worker to occupy the chair and to move out after the counting is over. A system supervisor can come at any convenient time and get a print out of the monitoring report in the standardised format or carry out any detailed analysis if required. The system has the software for calculating intakes and the committed effective doses using the latest ICRP methodologies, from the measured retained activities of the various important fission and activation products like 137Cs, 131I, 60Co, 125Sb etc. This type of system with trained staff is also expected to be of value in case of emergencies as a quick monitoring system.

Automation↗
PubMed2002

Ocular scrofuloderma with unilateral proptosis.

Proptosis due to an extraconal orbital abscess of tubercular origin with lacrimal gland involvement, representing ocular scrofuloderma, is a rare entity. This association has not been reported earlier in the literature. We describe a 7-year-old boy who presented with nodulo-ulcerative lesions of tubercular etiology with discharging sinuses on right side of the face and a similar lesion on the right lower eyelid along with proptosis of 4 months duration. Computerized tomography (CT) scan of the head confirmed the extraconal, intraorbital, hyperdense, homogeneously enhancing mass separated from the lateral rectus muscle and further revealed involvement of lacrimal gland along with erosion of the temporal bone. The patient showed marked improvement of his dermatological and ophthalmological lesions with anti-tubercular treatment. Subsequent ultrasound examinations of the orbit revealed regression in the size of the abscess from 10.7 mm to 5.0 mm and then complete disappearance of the abscess obviating surgical intervention.

Abscess↗
PubMed2002

Persistence of dengue-3 virus through transovarial transmission passage in successive generations of Aedes aegypti mosquitoes.

Progeny of Aedes aegypti mosquitoes infected intrathoracically with dengue-3 virus was reared to subsequent generations. In each generation, blood-fed females were confined individually and the eggs obtained from the transovarially infected females were pooled. The seventh generation obtained from the infected parental mosquitoes showed that virus could persist in mosquitoes in successive generations through transovarial passage. The rate of vertical transmission initially increased in the few generations (F1-F2), but in subsequent generations it was found to be steady. Parental mosquitoes inoculated with virus showed higher mortality than the diluent-inoculated controls. There was an increase in the larval duration of transovarially infected batches at the seventh generation when compared with uninfected control mosquitoes. The fecundity and fertility of the transovarially infected batches of mosquitoes was also affected when compared with the controls. This is the first report demonstrating persistence of dengue virus in the successive generations of mosquitoes infected through vertical transmission. These observations, which have great epidemiologic importance, suggest that vector mosquitoes may play an important role in the maintenance of virus in nature, and that mosquitoes may act as reservoirs of these viruses.

Aedes↗
PubMed2002

Breeding habitats and larval indices of Aedes aegypti (L) in residential areas of Rajahmundry town, Andhra Pradesh.

Entomological studies on relative prevalence and distribution of adults and immatures of Aedes aegypti were conducted in Rajahmundry town of Andhra Pradesh from December 1998 to November 1999. Adults and immature stages of Aedes aegypti were found in all the 22 localities viz; posh area (8), mixed area (8) and slum area (6) of the town. Larval indices were found to be higher in slum areas as compared to mixed or posh areas of the town. However, the larval habitats were observed to be similar in all localities. The larval indices were highest during monsoon and post-monsoon months. The breeding preference ratio (BPR) was highest for cement tubs followed by discarded tyres and barrels. The high larval indices of Aedes aegypti in these areas warrant intensification of vector surveillance activities along with source reduction and health education.

Aedes↗
PubMed2001

Tuberculosis of the vulva masquerading as a sexually transmitted disease.

Tuberculosis of the vulva is a rare condition usually seen by a gynecologist. We report a case of chronic ulcer on the vulva of four months duration, which, on detailed investigation, turned out to be a case of primary inoculation tuberculosis. The patient was subsequently put on antitubercular therapy with a good the therapeutic response. The rarity of this presentation in dermato-venereology is emphasized.

Adult↗
PubMed2001

Linear and whorled nevoid hypermelanosis.

Linear and whorled nevoid hypermelanosis (LWNHM) is a reticulate pigmentary disorder with a sporadic occurrence, representing genetic mosaicism. It is characterised by hyperpigmented macules in a reticulate pattern along Blaschko's lines, sparing the mucous membranes and stabilising after one to two years. It may be associated with various neurological abnormalities. The disorder may resemble incontinentia pigmenti, epidermal nevus, or zebra-like hyperpigmentation clinically. We report LWMNHM in a 15-year-old girl with progressively increasing streaks of reticulate hyperpigmented macules arranged in a whorled pattern over the trunk and extremities, which appeared soon after birth. There was no history of any preceding eruption or any associated systemic abnormality. Histopathological examination revealed basal cell hyperpigmentation without any pigmentary incontinence. CT scan of the brain was normal.

Abdomen↗
PubMed2001

A suspected case of primary cutaneous actinomycosis on the buttock.

Primary cutaneous actinomycosis is rare and can mimic mycetoma, tuberculosis and nocardiosis. The results of cultures (aerobic and anaerobic) are not always positive. A high degree of clinical suspicion should be entertained and a combination regimen of penicillins with sulphonamides should be used for treatment. We report a patient with primary cutaneous actinomycosis over the buttock, who was successfully treated with amoxicillin and sulphonamides.

Actinomycosis↗
PubMed2001

Status of soil transmitted helminthic infections in India--observations on sample surveys using Kato-Katz technique.

Results of surveys conducted in eight different ecologically homogenous zones in the country, using WHO sampling design methodologies and Kato-Katz technique are presented in this communication. Hilly and coastal areas had high STH prevalence ranging from 34%-36% with total epg ranging from 53,952-4,67,976. Apart from this, Chitradurga urban area had STH prevalence of 39.6% with epg of 81,792. However, except in few cases, in all these surveyed areas, intensity of STH infection was found to be light. A national programme for control of soil transmitted helminthic infections is advocated.

Animals↗
PubMed2000

Internal dosimetry of plutonium using the late urinary excretion.

An attempt has been made to standardize the methodology of internal dose computation from the late urinary excretion data. The methodology was selected keeping in mind the most recent ICRP publications and the results of internal dosimetry intercomparison studies reported in literature. The key element of this methodology is the PC-based computational software LUDEP 2.05, which implements the new model of the human respiratory tract. Late urinary excretion data of three male subjects involved in accidental intakes of plutonium aerosols more than 25 years ago were interpreted in terms of intakes and internal doses with the aid of the standardized methodology. An important implication of this work is that late urinary excretion data of the occupational workers of any plutonium handling facility could be used to show the compliance with the life-time dose limit.

Aerosols↗