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Biomedical subjects

S Kamboj

Publications and source records attributed to S Kamboj.

12 recordsLinked to original sources
PubMed2002

External exposure model in the RESRAD computer code.

An external exposure model has been developed for the RESRAD computer code that provides flexibility in modeling soil contamination configurations for calculating external doses to exposed individuals. This model is based on the dose coefficients given in the U.S. Environmental Protection Agency's Federal Guidance Report No. 12 (FGR-12) and the point kernel method. It extends the applicability of FGR-12 data to include the effects of different source geometries, such as cover thickness, source thickness, source area, and shape of contaminated area of a specific site. A depth factor function was developed to express the dependence of the dose on the source thickness. A cover-and-depth factor function, derived from this depth factor function, takes into account the dependence of dose on the thickness of the source region and the thickness of the cover above the source region. To further extend the model for realistic geometries, area and shape factors were derived that depend not only on the lateral extent of the contamination, but also on source thickness, cover thickness, and radionuclides present. Results obtained with the model generally compare well with those from the Monte Carlo N-Particle transport code.

Computer Simulation↗
PubMed2001

A predictable outcome of a preventable disease.

Infective endocarditis is a systemic illness that can present with a variety of non-specific clinical symptoms. Patients with certain underlying heart valve abnormalities are at increased risk for development of infective endocarditis while undergoing minor procedures, particularly those associated with bacteremia by pathogens that typically cause infective endocarditis. We present a case of infective endocarditis that developed after a dental procedure in a patient with a previously undetected congential bicuspid aortic valve.

Adult↗
PubMed1999

Protocols for implementing DOE authorized release of radioactive scrap metals.

A process to implement the U.S. Department of Energy's (DOE) policy for authorized release of radioactive materials from DOE facilities is provided in the Draft Handbook for Controlling Release for Reuse or Recycle of Property Containing Residual Radioactive Material, published by DOE in 1997 and distributed to DOE field offices for interim use and implementation. The authorized release of such property is intended to permit its beneficial use across the entire DOE complex. A computerized management tool--P2Pro(RSM)--has been developed to aid in carrying out the release process for radioactive metals. It contains protocols for the authorized release process and relevant information to facilitate the evaluation of scrap metals for reuse and recycle. The P2Pro(RSM) protocols provide DOE and its contractors with an effective, user-friendly tool for managing authorized release activities P2Pro(RSM) is designed to be used in the Windows environment. The protocols incorporate a relational database coupled with a graphic-user interface to guide the user through the appropriate steps so authorized release limits can be developed. With the information provided in the database, an as-low-as-reasonably-achievable (ALARA) optimization process can be easily set up and run for up to 10 alternatives for disposition of radioactive scrap metals. The results of the ALARA optimization process can be printed in a series of reports and submitted as part of the application for the authorized release of the radioactive scrap metals.

Documentation↗
PubMed1999

Cost of medications for elderly in a nursing home.

The rising cost of medical care, particularly for elderly patients in nursing homes, is receiving increasing attention. The purpose of this study was to investigate the cost of and the average number of medications taken per patient in a nursing home. The study included 116 residents of a nursing home in New Orleans, Louisiana. Relevant information about the number of medications taken by each patient on a regular basis was obtained by chart review. The cost of medications was calculated from the Red Book (which represents the cost of drugs to the pharmacy), because the medication prices charged by the nursing home were not available. The number of medications used per patient per day expressed as mean +/- S.D. was 8.1 +/- 4.1. The cost of medications per patient per month expressed as mean +/- S.D. was $182 +/- 141. The estimated annual cost of medications per patient was $2,184. It is highly likely that the cost to the patient is higher than the cost shown here. This preliminary study shows that elderly patients take several medications associated with significant expense.

Aged↗
PubMed1998

Receptor clustering: activate to accumulate?

Postsynaptic receptor clustering is thought to be of critical importance in central neurotransmission. Recent work suggests that the formation and size of such clusters may depend on synaptic activity, although that dependence appears to vary according to the type of receptor that mediates the postsynaptic response.

Animals↗
PubMed1998

Interaction of the N-ethylmaleimide-sensitive factor with AMPA receptors.

Glutamate receptors mediate the majority of rapid excitatory synaptic transmission in the central nervous system (CNS) and play important roles in synaptic plasticity and neuronal development. Recently, protein-protein interactions with the C-terminal domain of glutamate receptor subunits have been shown to be involved in the modulation of receptor function and clustering at excitatory synapses. In this paper, we have found that the N-ethylmaleimide-sensitive factor (NSF), a protein involved in membrane fusion events, specifically interacts with the C terminus of the GluR2 and GluR4c subunits of AMPA receptors in vitro and in vivo. Moreover, intracellular perfusion of neurons with a synthetic peptide that competes with the interaction of NSF and AMPA receptor subunits rapidly decreases the amplitude of miniature excitatory postsynaptic currents (mEPSCs), suggesting that NSF regulates AMPA receptor function.

Amino Acid Sequence↗
PubMed1998

Activity-dependent modulation of synaptic AMPA receptor accumulation.

Both theoretical and experimental work have suggested that central neurons compensate for changes in excitatory synaptic input in order to maintain a relatively constant output. We report here that inhibition of excitatory synaptic transmission in cultured spinal neurons leads to an increase in mEPSC amplitudes, accompanied by an equivalent increase in the accumulation of AMPA receptors at synapses. Conversely, increasing excitatory synaptic activity leads to a decrease in synaptic AMPA receptors and a decline in mEPSC amplitude. The time course of this synaptic remodeling is slow, similar to the metabolic half-life of neuronal AMPA receptors. Moreover, inhibiting excitatory synaptic transmission significantly prolongs the half-life of the AMPA receptor subunit GluR1, suggesting that synaptic activity modulates the size of the mEPSC by regulating the turnover of postsynaptic AMPA receptors.

2-Amino-5-phosphonovalerate↗
PubMed1996

Evaluation of Monte Carlo simulation of photon counting efficiency for germanium detectors.

The reliability of calculating the full-energy peak counting efficiency of germanium detectors by Monte Carlo simulation was evaluated by comparing MCNP-4 code results with measurements over a range of conditions. The measurements were performed for two detectors of 20% and 110% nominal efficiencies with a point source at two distances and with four different volume sources, including a reentrant beaker, placed on the end caps. The radionuclides were National Institute of Standards and Technology standard sources that emit photons between energies of 42.8 and 1,596.4 keV. Each detector was modeled in detail with respect to the dimensions of the detection volume and attenuation material in the can, dead-layer, and crystal holder foil. The measurements of the 42.8-keV photon were used to check dimensions and to change slightly the value of the dead-layer thickness so that the simulation agreed with measurements at this energy. After this adjustment, the average ratio of simulation results to measurements for 13 photon energies above 42.8 keV was between 0.97 and 1.03 for all sets of point and volume source comparisons. Ratios at individual energies were between 0.92 and 1.06 for the point source and between 0.94 and 1.09 for volume sources. The observed differences were consistent with the estimated standard deviations of simulation and of measurement, which ranged from 1 to 6% and typically were 2 to 3% except for larger uncertainties at low energies. On the basis of this comparison, simulation with the MCNP-4 code is equivalent to measurement with photon standards if the detector and source configuration can be modeled within a tenth of a millimeter.

Germanium↗
PubMed1993

Radium needle used to calibrate germanium gamma-ray detector.

A standard platinum-iridium needle that contains 374 MBq 226Ra was tested as a source for calibrating a portable germanium detector used with a gamma-ray spectrometer for environmental radioactivity measurements. The counting efficiencies of the 11 most intense gamma rays emitted by 226Ra and its short-lived radioactive progeny at energies between 186 and 2,448 keV were determined, at the full energy peaks, to construct a curve of counting efficiency vs. energy. The curve was compared to another curve between 43 and 1,596 keV obtained with a NIST mixed-radionuclide standard. It was also compared to the results of a Monte Carlo simulation. The 226Ra source results were consistent with the NIST standard between 248 and 1,596 keV. The Monte Carlo simulation gave a curve parallel to the curve for the combined radium and NIST standard data between 250 and 2,000 keV, but at higher efficiency.

Calibration↗
PubMedDate not supplied

Correlative study of histopathology and bacteriology in patients of tubercular lymphadenitis.

Histopathology as well as bacteriology of lymph node specimen are useful diagnostic tools for tuberculous lymphadenitis. In the present study, a total of 71 cases of lymphadenitis were selected for histopathological and bacteriological studies. Only 46 patients had caseating type and 4 had non-caseating type of tuberculous lymphadenitis while 21 patients revealed non-specific chronic lymphadenitis on histopathological examination. Only 6 lymph node smears were positive for acid fast bacilli (AFB), 19 cases were positive for mycobacterial culture growth. Thus, it is not necessary that the cases which are histopathologically positive will be positive for culture as well. Therefore, both bacteriology and histopathology are complimentary diagnostic tools for tuberculous lymphadenitis.

Adult↗