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Biomedical subjects

S M Reddy

Publications and source records attributed to S M Reddy.

At least 37 records · Page 2Linked to original sources
PubMed1997

Ion exchanger modified PVC membranes--selectivity studies and response amplification of oxalate and lactate enzyme electrodes.

We report on a novel method of oxidase enzyme electrode response amplification, using unplasticized PVC and plasticized PVC, respectively. The anion exchanger tricaprylylmethylammonium chloride (Aliquat 336s) and hydrophobic isopropylmyristate (IPM) plasticizer have been used together to modify PVC. Resulting structures are anionic substrate selective and hydrogen peroxide impermeable and can be used as outer membranes of a classical dual membrane amperometric enzyme electrode where an oxidase is used to generate H2O2 for electrochemical detection. Their effect on sensor sensitivity and linearity is considered.

Biosensing Techniques↗
PubMed1997

Cloning, sequence analysis and expression of the major outer capsid protein gene of an aquareovirus.

The nucleotide and deduced amino acid sequences of genome segment 10 of aquareovirus strain SBR, encoding the major outer capsid protein (VP7), have been determined. Genome segment 10 of SBR virus is 986 nucleotides long and encodes a polypeptide of 298 amino acids with a predicted molecular mass of 32,430 Da. There are 26 non-translated nucleotides at the 5' end and 66 non-translated nucleotides at the 3' end. Using a recombinant baculovirus system, the VP7 protein of SBR virus was expressed to a high level. The baculovirus-produced VP7 protein was similar both in its size and antigenic properties to the authentic aquareovirus VP7 protein. Antiserum from a rabbit immunized with the baculovirus-produced VP7 protein failed to neutralize the homologous aquareovirus strain. As determined by Western blotting, this antiserum reacted with aquareovirus strains belonging to the same genogroup as SBR virus, but did not react with aquareovirus strains belonging to the other genogroups.

Animals↗
PubMed1995

Evaluation of Community Care Network (CCN) system in a rural health care setting.

Concurrent Engineering Research Center (CERC), under the sponsorship of NLM (National Library of Medicine) is in the process of developing a computerized patient record system for a clinical environment distributed in rural West Virginia. This realization of the CCN (Community Care Network), besides providing computer-based patient records accessible from a chain of clinics and one hospital, supports collaborative health care processes like referral and consulting. To evaluate the effectiveness of the system, a study was designed and is in the process of being executed. Three surveys were designed to provide subjective measures, and four experiments for collecting objective data. Data collection is taking place in several phases: baseline data are collected before the system is deployed; the process is repeated with minimal changes three, then six months later or as often as new versions of the system are installed. Results are then to be compared, using whenever possible matching techniques (i.e. the preliminary data collected on a provider will be matched with the data collected later on the same provider). Surveys are conducted through questionnaires distributed to providers and nurses and person-to-person interviews of the patients. The time spent on patient-chart related activities is measured by work-sampling, aided by a computer application running on a laptop PC. Information about missing patient record parts is collected by the providers, the frequency by which new features of the computerized system are used will be logged by the system itself and clinical outcome measures will be studied from the results of the clinics' own patient chart audits. Preliminary results of the surveys and plans for the immediate and distant future are discussed at the end of the paper.

Attitude to Computers↗
PubMed1994

Selective membranes for the construction and optimization of an amperometric oxalate enzyme electrode.

Oxalate oxidase has been immobilized within a membrane laminate. Integration of the laminate within an amperometric electrode afforded a sensor for determining oxalate via electrochemical oxidation of H2O2 and subsequent current generation. A study of novel poly(vinyl chloride) (PVC) and cellulose acetate (CA) membranes with various outer/inner membrane configurations made it possible to eliminate direct electrochemical interference from species present in urine, typically ascorbate (60-500 mumol l-1), homovanillic acid (40-60 mumol l-1) and oxalate itself (50-500 mumol l-1). Of the membranes studied, only CA and plasticized PVC were found to screen out the direct oxalate electrochemical signal effectively. Cellulose acetate exhibited the best selectivity ratio for H2O2 over urine interference. An outer 0.05 micron pore radius polycarbonate membrane imparted sensor linearity in the narrow range 2-200 mumol l-1 oxalate, which fell below the normal range of oxalate in urine. The application of unplasticized PVC as an outer membrane allowed the sensor to exhibit linear characteristics which extended beyond the clinically relevant range (> 700 mumol l-1). The Michaelis-Menten constant of the immobilized enzyme was measured and found to be 10(-3) mol l-1.

Biosensing Techniques↗
PubMed1993

ARTEMIS: a collaborative framework for health care.

Patient centered healthcare delivery is an inherently collaborative process. This involves a wide range of individuals and organizations with diverse perspectives: primary care physicians, hospital administrators, labs, clinics, and insurance. The key to cost reduction and quality improvement in health care is effective management of this collaborative process. The use of multi-media collaboration technology can facilitate timely delivery of patient care and reduce cost at the same time. During the last five years, the Concurrent Engineering Research Center (CERC), under the sponsorship of DARPA (Defense Advanced Research Projects Agency, recently renamed ARPA) developed a number of generic key subsystems of a comprehensive collaboration environment. These subsystems are intended to overcome the barriers that inhibit the collaborative process. Three subsystems developed under this program include: MONET (Meeting On the Net)--to provide consultation over a computer network, ISS (Information Sharing Server)--to provide access to multi-media information, and PCB (Project Coordination Board)--to better coordinate focussed activities. These systems have been integrated into an open environment to enable collaborative processes. This environment is being used to create a wide-area (geographically distributed) research testbed under DARPA sponsorship, ARTEMIS (Advance Research Testbed for Medical Informatics) to explore the collaborative health care processes. We believe this technology will play a key role in the current national thrust to reengineer the present health-care delivery system.

Computer Communication Networks↗
PubMed1992

Effect of carbon and nitrogen sources on the production of penitrem B by Penicillium aurantiogriseum.

Effect of different carbon and nitrogen sources on the production of penitrem B was studied. D-Xylose induced maximum penitrem B production, while melibiose, glycerol, citric acid and succinic acid were poor substrates. Potassium nitrate, L-asparagine, sodium nitrate, glycine, DL-aspartic acid and L-tryptophan supported good production of penitrem B. Conversely zirconyl nitrate, barium nitrate, aluminum nitrate, acetanilide, 4-aminobenzoic acid, 4-nitrobenzoic acid and 4-nitroaniline were toxic and did not even permit the growth of the fungus.

Carbon↗
PubMedDate not supplied

High virus titer in feather pulp of chickens infected with subgroup J avian leukosis virus.

Subgroup J avian leukosis viruses (ALVs), which are a recombinant virus between exogenous and endogenous ALVs, can spread by either vertical or horizontal transmission. Exogenous and endogenous ALVs can be detected in feather pulp. In this study, virus titers in feather pulp of chickens infected with subgroup J ALV were compared with those of plasma and cloacal swab. All of the broiler chickens inoculated with subgroup J ALV at 1 day old were positive for virus from feather pulp during the experimental period of between 2 wk and 8 wk of age. Virus titers in feather pulp of some broiler chickens infected with subgroup J ALV were very high, ranging from 10(7) to 10(8) infective units per 0.2 ml. Virus titers in feather pulp were usually the highest among the samples of plasma, cloacal swab, and feather pulp tested. In another experiment in which layer chickens were inoculated with subgroup J ALV at 1 day old, virus was detected in feather pulp from 2 wk until 18 wk of age, and virus persisted longer in feather pulp than in plasma. Almost all of the layer chickens tested were positive for virus by polymerase chain reaction (PCR) with DNA extracted from feather pulp samples at 2, 4, and 10 wk of age, and the PCR from feather pulp was more sensitive than virus isolation from plasma, cloacal swab, and feather pulp. All above results indicate that samples of feather pulp can be useful for virus isolation and PCR to confirm subgroup J ALV infection.

Animals↗
PubMedDate not supplied

Protection and synergism by recombinant fowl pox vaccines expressing multiple genes from Marek's disease virus.

Recombinant fowl poxviruses (rFPVs) were constructed to express genes from serotype 1 Marek's disease virus (MDV) coding for glycoproteins B, E, I, H, and UL32 (gB1, gE, gI, gH, and UL32). An additional rFPV was constructed to contain four MDV genes (gB1, gE, gI, and UL32). These rFPVs were evaluated for their ability to protect maternal antibody-positive chickens against challenge with highly virulent MDV isolates. The protection induced by a single rFPV/gB1 (42%) confirmed our previous finding. The protection induced by rFPV/gI (43%), rFPV/gB1UL32 (46%), rFPV/gB1gEgI (72%), and rFPV/gB1gEgIUL32 (70%) contributed to additional knowledge on MDV genes involved in protective immunity. In contrast, the rFPV containing gE, gH, or UL32 did not induce significant protection compared with turkey herpesvirus (HVT). Levels of protection by rFPV/gB1 and rFPV/gl were comparable with that of HVT. Only gB1 and gI conferred synergism in rFPV containing these two genes. Protection by both rFPV/gB1gEgI (72%) and rFPV/gB1gEgIUL32(70%) against Marek's disease was significantly enhanced compared with a single gB1 or gI gene (40%). This protective synergism between gB1 and gI in rFPVs may be the basis for better protection when bivalent vaccines between serotypes 2 and 3 were used. When rFPV/gB1gIgEUL32 + HVT were used as vaccine against Md5 challenge, the protection was significantly enhanced (94%). This synergism between rFPV/gB1gIgEUL32 and HVT indicates additional genes yet to be discovered in HVT may be responsible for the enhancement.

Animals↗
PubMedDate not supplied

Brachytherapy for prostate cancer.

Brachytherapy is one of the oldest techniques of radiation therapy for prostate cancer. However, its use has been controversial due to mixed results with older implant techniques and the availability of different treatment methods. New methods of brachytherapy based on improved technology and increased understanding of radiobiology hold promise for consistently improved results. This article describe the various methods of prostate brachytherapy and reviews the clinical results for these methods.

Brachytherapy↗
PubMedDate not supplied

Identification and structural analysis of a MDV gene encoding a protein kinase.

DNA sequence analysis of the BamHI-C fragment of Marek's Disease Virus (MDV) reveals the presence of a 513 amino acid open reading frame (ORF). This ORF codes for a protein with an estimated M(r) of 58,901. Comparison of the amino acid sequence with those available in the Swiss-Prot database indicates extensive homology with a protein kinase (PK) of herpes simplex virus (HSV) and varicella-zoster virus (VZV). In Northern blot hybridization, a transcript of 2.0 kb was detected in MDV (GA strain) infected duck embryo fibroblasts (DEFs). A portion of the ORF was expressed in Escherichia coli as a trpE-fusion protein and used to generate antiserum in New Zealand rabbits. This antiserum specifically detected a protein of 60 kDa in MDV serotype 1, 2 and 3 infected DEFs or chicken embryo fibroblasts (CEFs) by Western blot analysis. This ORF codes for a functional PK.

Amino Acid Sequence↗
PubMedDate not supplied

Development of a quantitative-competitive polymerase chain reaction assay for serotype 1 Marek's disease virus.

We have developed a quantitative-competitive (QC) polymerase chain reaction (PCR) for the detection of Marek's disease virus (MDV) DNA. The assay utilizes a competitor DNA that differs from the viral DNA of interest by having a small insertion. The competitor DNA acts as an internal standard for the estimation of viral DNA in an unknown sample. The amount of viral DNA in a sample is quantitated by coamplification in the presence of a known amount of competitor DNA. The same PCR primers that amplify the viral DNA also amplify the competitor DNA. When the amount of competitor is equal to the amount of viral DNA in a sample, there is equal amplification of the competitor and the virus. Thus, we are able to quantitate the viral DNA in an unknown sample. To establish the utility of this assay, in vivo correlations between virulence and virus replication were studied. Our data demonstrated that a more virulent strain of MDV (648A) replicated better in thymus during cytolytic infection than did a less virulent strain (GA). However, no differences in virus titer were observed when these two viruses were propagated in tissue culture. Our data are consistent with the generally held idea that "hot" strains of MDV replicate earlier and better in birds. Thus, QC-PCR is extremely specific and sensitive to measure MDV DNA over a wide range and can be applied to in vivo studies of viral pathogenesis.

Animals↗
PubMedDate not supplied

Coinfection of specific-pathogen-free chickens with Marek's disease virus (MDV) and chicken infectious anemia virus: effect of MDV pathotype.

Both Marek's disease virus (MDV) and chicken infectious anemia virus (CIAV) infections are prevalent in chickens throughout the world. In the past decade, MDV strains with increased virulence (very virulent plus MDV pathotype [vv+MDV]) have been isolated. The purpose of this experiment was to determine the effects of coinfection of chickens with CIAV and a vv+MDV isolate. Specific-pathogen-free chickens were inoculated at 1 day posthatch with RB1B (very virulent MDV pathotype [vvMDV]) only, 584A (vv+MDV) only, CIAV only, RB1B + CIAV, 584A + CIAV, or nothing. Samples of spleen, thymus, and bursa of Fabricius were collected at 4, 7, 10, and 13 days postinoculation (DPI). Thymic and bursal atrophy at 13 DPI and final mortality at 30 DPI were significantly greater in chickens inoculated with 584A with or without added CIAV, or with RB1B plus CIAV, compared with birds inoculated with RB1B alone. Both amounts of virus reisolated and levels of virus detected by quantitative-competitive polymerase chain reaction were greater at 4 DPI in 584A inoculates compared with RB1B inoculates. To monitor the early cytolytic infection, northern analysis was done with a probe for the MDV immediate early gene ICP4 (infected cell protein 4). In the absence of CIAV, ICP4 expression was more apparent in chickens inoculated with 584A than in those inoculated with RB1B. CIAV coinfection increased ICP4 expression in the spleens of chickens infected with RB1B. These results indicated that inoculation of chickens with the 584A isolate caused a more robust early cytolytic infection compared with inoculation with RB1B alone and support the classification of 584A as a vv+MDV strain. Coinfection with CIAV exacerbated vvMDV strain RB1B infection. The extent of this exacerbation was less evident when birds were coinfected with 584A and CIAV.

Animals↗