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Biomedical subjects

R Raman

Publications and source records attributed to R Raman.

At least 91 records · Page 5Linked to original sources
PubMed1997

Experiences with ARTEMIS--an Internet-based telemedicine system.

ARTEMIS is one of the first systems to exploit the Internet/Intranet technologies for exchanging patient information among health care providers. The primary project goal was to develop and demonstrate a regional telehealth environment specifically to support real-time consultations among health care providers via a computer network, provide secure access to multi-media patient records and discharge summaries, facilitate authentication/digital sign-off, multi-media mail-based referrals, and network-based dictation/transcription. A prototype is deployed in southern West Virginia in a Community Care Network (CCN). The CCN consists of providers, hospitals, clinics, laboratories, that make up one "Virtual" clinic on the "Intranet". ARTEMIS employs new technologies such as Java and JavaScript for the browser, and CORBA-based "middleware" for interoperability at the server-end. Several experiments were designed for evaluating the impact of ARTEMIS on patient care. In this paper we discuss the challenges we faced and the means by which we plan to meet these challenges. We conclude by outlining new thrust areas in which we are concentrating in our next phase of development of ARTEMIS.

Computer Communication Networks↗
PubMed1996

Anisakiasis of the tonsils.

A six-year-old Indian girl presenting with clinical features of chronic recurrent tonsillitis, had a tonsillectomy. Histopathology revealed a cross-section of an Anisakis worm in the tonsil. This report documents a new location in the human host for this rare parasite.

Anisakiasis↗
PubMed1996

Heterotopia of the tonsil.

The histopathological finding of heterotopias or choristoma is rare. This paper describes two patients who presented with chronic recurrent tonsillitis and underwent tonsillectomy. Histological examination revealed heterotopic cartilage in the tonsil of one patient and bone in that of the other.

Adult↗
PubMed1996

Nasosinusal fungal granuloma--clinical profile.

Fifty cases of nasosinusal fungal granuloma were admitted under the ENT Department in a teaching tertiary care hospital in India during a thirteen-year period. Aspergillus species was found to be the most common causative fungus (29) followed by Mucorales (14), Entomophthorales (5) and Fusarium (2) species. There were 13 cases of non-invasive and 16 cases of invasive variants of Aspergillosis. In spite of intravenous amphotericin B therapy and radical surgical debridement, 81% in the invasive group showed relapse and required prolonged oral antifungal drugs and multiple surgical procedures. Among the 14 cases of Mucormycosis, all of the 10 cases who received intravenous amphotericin B and radical surgery showed complete recovery with no relapse over a period of 2 to 10 years. This is contrary to earlier published reports which suggest poor prognosis. The entomophthoromycosis received oral steroids and cotrimoxazole, and oral potassium iodide or intravenous amphotericin in case of relapse. Both the cases of Fusariosis recovered completely with oral ketoconazole.

Adolescent↗
PubMed1995

5-Aza deoxyCytidine-induced inhibition of differentiation of spermatogonia into spermatocytes in the mouse.

In order to explore the significance of DNA methylation in proliferation and differentiation of germ cells in testis, 5-aza,2'-deoxyCytidine (5-azaCdR), a hypomethylating agent, was administered in vivo to neonatal mice having only spermatogonial (premeiotic) cells. End-labeling of the MspI, HpaII, and HhaI digested DNA revealed considerable loss of methylation following the treatment. Cellular and histological preparations of the testis showed complete inhibition of differentiation into spermatocytic stage. Analysis of protein synthesis in the treated and control testis by growing the cells in 35S-Methionine medium and resolving the lysate by SDS-PAGE revealed that the programme of expression of at least 5 polypeptides (35.0, 31.5, 27.0, 22.5, and 18.0 KD) was altered as a result of 5-azaCdR incorporation. It appears that DNA methylation plays a critical role in the differentiation of gonia into primary spermatocytes.

Animals↗
PubMed1995

Glycine decarboxylase: protein chemistry and molecular biology of the major protein in leaf mitochondria.

The four component proteins of the glycine decarboxylase multienzyme complex (the P-, H-, T-, and L-proteins) comprise over one-third of the soluble proteins in mitochondria isolated from the leaves of C3 plants. Together with serine hydroxymethyltransferase, glycine decarboxylase converts glycine to serine and is the site of photorespiratory CO2 and NH3 release. The component proteins of the complex are encoded on nuclear genes with N-terminal presequences that target them to the mitochondria. The isolated complex readily dissociates into its component proteins and reassociates into the intact complex in vitro. Because of the intimate association between photosynthesis and photorespiration, the proteins of the complex are present at higher levels in leaves in the light. The expression of these genes is controlled at the transcriptional level and the kinetics of expression are closely related to those of the small subunit of Rubisco. Deletion analysis of fusions between the promoter of the H-protein of the complex and the reporter gene beta-glucuronidase in transgenic tobacco has identified a region responsible for the tissue specificity and light dependence of gene expression. Gel shift experiments show that a nuclear protein in leaves binds to this region. Glycine decarboxylase has proven to be an excellent system for studying problems in plant biochemistry ranging from protein-protein interactions to control of gene expression.

Amino Acid Oxidoreductases↗
PubMed1995

Cytological evaluation of global DNA methylation in mouse testicular genome.

Global methylation of DNA from different testicular cell types has been studied by DNA end-labeling and nick translation of fixed chromatin (in situ), following digestion with cytosine methylation-sensitive restriction enzymes. Both at the level of chromatic (chromosome) and naked DNA, there is extensive methylation of the genome. Although the extent of methylation was nearly the same among different cell types in the MspI, HpaII, and HhaI digested end-labelled DNA, in the chromosome preparations the digestion patterns varied in cell type-specific manner, pachytene being the most sensitive and spermatids and sperm the most resistant. The differential sensitivity is attributable to the difference in the chromatin organisation in different testicular cell types though no specific region could be identified as particularly more sensitive or resistant to the enzymes. Pachytene bivalents do not reveal a consistent segmental pattern of digestion, but the perichiasmate regions of diplotene/diakinesis and metaphase I chromosomes show hypersensitivity to the enzymes.

Animals↗
PubMed1995

Brain regional distribution pattern of metabolite signal intensities in young adults by proton magnetic resonance spectroscopic imaging.

Proton magnetic resonance spectroscopy (1H-MRS) is evolving from single-volume localized acquisitions to multiple-volume acquisitions using magnetic resonance spectroscopic imaging (1H-MRSI). The normal regional patterns of 1H-MRSI-detectable metabolite signal intensities have yet to be established. We studied 13 healthy young adults with a multiple-section 1H-MRSI technique. The metabolite signals measured were N-acetylaspartate (NA), choline-containing compounds (CHO), creatine-phosphocreatine (CRE), and lactate. Ten neuroanatomic regions (nine bilateral) were identified in gray matter, white matter, and basal nuclei. Analysis of the data led to the following conclusions: (1) NA and CHO signals from centrum semiovale (CSO) can be used as a normalizing factor to reduce intersubject variability due to external causes; (2) in normal human brain, there is no left versus right asymmetry in the regions studied; (3) statistically significant patterns of signal distribution of NA, CHO, and CRE can be identified in normal human brain; and (4) CSO-normalized metabolite signal intensities and metabolite ratios complement each other for the detection of significant regional differences.

Adult↗
PubMed1995

Decreased cerebral glucose metabolism in patients with brain tumors: an effect of corticosteroids.

The authors measured cerebral glucose metabolism (CMRglu) using [18F]fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) in patients with brain tumors to evaluate the effect of exogenous corticosteroids (in this instance, dexamethasone) on glucose metabolism. Fifty-six FDG-PET studies obtained in 45 patients with unilateral supratentorial brain tumors were analyzed. Patients with brain tumors were divided into three groups: 1) patients with cushingoid symptoms, who had been treated with combinations of radiotherapy and chemotherapy taking oral dexamethasone; 2) patients not taking dexamethasone but treated with radiotherapy; and 3) patients not taking dexamethasone who had not been treated with radiotherapy. Serial FDG-PET scans were obtained in eight of the cushingoid patients. Glucose metabolism was measured in the contralateral cerebral and ipsilateral cerebellar hemispheres in patients and compared to measurements taken from 19 normal volunteers. The authors found that in the cushingoid brain tumor patients there was a marked reduction in CMRglu compared to normal volunteers and other brain tumor patients (Kruskal-Wallis test; p 0.001). In the majority of patients who had serial FDG-PET scans, there was a decline in glucose metabolism over time and in one patient, in whom dexamethasone was reduced in dosage, there was a subsequent increase in CMRglu. The authors conclude that there is a generalized reduction in CMRglu in brain tumor patients taking dexamethasone compared to other brain tumor patients and normal volunteers, and that this effect is independent of radiotherapy, concurrent anticonvulsant medication, and transhemispheric functional disconnection (transhemispheric diaschisis).

Adult↗
PubMed1995

Correlative morphologic and functional imaging for diagnosis, staging and follow up in AIDS: an overview.

The immunocompromised patient can be affected by different opportunistic infections and tumors, that can involve all organ systems, and particularly, the central nervous system, the respiratory system, the gastrointestinal tract. The extreme variability of AIDS presentations requires a specific preparation and cooperation between the different diagnostic imaging specialists and a close collaboration with the clinicians. With AIDS, different morphologic and functional imaging techniques can be used for detection of disease sites, assessment of the extent of the disease and monitoring of disease changes over time and response to treatment. The complexity of AIDS presentations is such that full integration of the complementary information obtained with different techniques could be most useful. Image registration (coregistration, fusion) indicates approaches where precise spatial cross-references are obtained, in order to combine the information acquired with different imaging modalities, in particular by blending morphologic CT/MRI data with functional SPET/PET data. In this paper, an overview of the developments in the field of "image fusion" follows some comments on the results of morphologic and functional assessment of brain, chest and abdominal diseases in the course of AIDS, as illustrative examples of the potential benefits of multimodality image correlation.

AIDS-Related Opportunistic Infections↗
PubMed1995

PET-FDG of pleomorphic xanthoastrocytoma.

A young patient with pleomorphic xanthoastrocytoma (PXA), a usually benign cerebral tumor, had two recurrences in a short time period. The clinical, pathological and neuroradiological features, including PET with [18F]-fluorodeoxyglucose (FDG), are presented. The PET-FDG study revealed the recurrent tumor to be hypermetabolic. The diagnosis was confirmed histopathologically. As the clinical outcome of patients harboring PXA is not easy to predict because of possible recurrence and/or transformation into more aggressive gliomas, we discuss the predictive indicators of more aggressive clinical behavior.

Adult↗
PubMed1995

An overview of the CERC ARTEMIS project.

The basic premise of this effort is that health care can be made more effective and affordable by applying modern computer technology to improve collaboration among diverse and distributed health care providers. Information sharing, communication, and coordination are basic elements of any collaborative endeavor. In the health care domain, collaboration is characterized by cooperative activities by health care providers to deliver total and real-time care for their patients. Communication between providers and managed access to distributed patient records should enable health care providers to make informed decisions about their patients in a timely manner. With an effective medical information infrastructure in place, a patient will be able to visit any health care provider with access to the network, and the provider will be able to use relevant information from even the last episode of care in the patient record. Such a patient-centered perspective is in keeping with the real mission of health care providers. Today, an easy-to-use, integrated health care network is not in place in any community, even though current technology makes such a network possible. Large health care systems have deployed partial and disparate systems that address different elements of collaboration. But these islands of automation have not been integrated to facilitate cooperation among health care providers in large communities or nationally. CERC and its team members at Valley Health Systems, Inc., St. Marys Hospital and Cabell Huntington Hospital form a consortium committed to improving collaboration among the diverse and distributed providers in the health care arena. As the first contract recipient of the multi-agency High Performance Computing and Communications (HPCC) Initiative, this team of computer system developers, practicing rural physicians, community care groups, health care researchers, and tertiary care providers are using research prototypes and commercial off-the-shelf technologies to develop an open collaboration environment for the health care domain. This environment is called ARTEMIS--Advanced Research TEstbed for Medical InformaticS.

Computer Communication Networks↗
PubMed1993

Oocytes from pachytene to dictyotene can easily be analysed in neonatal rodents.

We have investigated the dynamics of meiotic prophase I in neonatal ovaries from different wild rodent species, from a laboratory strain of Mus musculus and from Mus musculus x Mus spretus F1 hybrids. We found that almost all stages of prophase I were regularly present in neonatal ovaries from these species and that their transcriptional activity can be assessed by [3H]-uridine incorporation, indicating that postnatal analysis of meiotic chromosomes and synapsis may be conducted as an alternative to the investigation of foetal ovaries.

Animals↗
PubMed1993

Medical therapy of rhinosporidiosis with dapsone.

Clinical, histopathological and ultrastructural studies in three cases of rhinosporidiosis show complete remission of infection within one year of therapy with dapsone. Light and electron microscope studies confirmed arrest of the maturation of the spores and accentuated granulomatous response with fibrosis following dapsone therapy.

Administration, Oral↗
PubMed1993

External laryngeal trauma: analysis of thirty cases.

A retrospective analysis of thirty patients with external laryngeal trauma was performed to assess the type and extent of injuries commonly seen as well as the outcome following treatment. Outcome was assessed both in terms of voice and airway. Major laryngeal injuries (19 cases) outnumbered minor injuries (11 cases). A good correlation exists between the symptoms of haemoptysis and stridor at presentation and severity of the injury (p = 0.002). Early surgical intervention is associated with better outcome (p = 0.01). However there is no statistically significant difference in outcome between major and minor injuries (p = 0.3) indicating that other factors are operative in determining outcome. Based on our findings a management strategy for patients with external laryngeal trauma is outlined.

Adolescent↗
PubMed1993

Mammalian sex chromosomes. VI. Synapsis in the heterochromatin-rich X chromosomes of four rodent species, Mus dunni, Bandicota bengalensis, Mesocricetus auratus, and Nesokia indica.

This study analyzes the progression of chromosomal synapsis in female meiosis of four rodent species, Mus dunni, Bandicota bengalensis, Mesocricetus auratus, and Nesokia indica. Special attention has been paid to understand the mode of pairing between heterochromatin-rich X chromosomes. The ovaries were obtained from newborn individuals instead of fetuses. In all but M. auratus, day 0 ovaries provided almost all the prophase stages at varying frequencies. In B. bengalensis and M. dunni the entire X chromosomes were paired including the heterochromatin. In M. auratus and N. indica, the heterochromatic arms in a proportion of X bivalents, however, were only partially synapsed. It appears that in these two species heterochromatin association is either delayed or short lived.

Animals↗