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Biomedical subjects

N D Kumar

Publications and source records attributed to N D Kumar.

14 recordsLinked to original sources
PubMed2006

A photometric redshift of z = 6.39 +/- 0.12 for GRB 050904.

Gamma-ray bursts (GRBs) and their afterglows are the most brilliant transient events in the Universe. Both the bursts themselves and their afterglows have been predicted to be visible out to redshifts of z approximately 20, and therefore to be powerful probes of the early Universe. The burst GRB 000131, at z = 4.50, was hitherto the most distant such event identified. Here we report the discovery of the bright near-infrared afterglow of GRB 050904 (ref. 4). From our measurements of the near-infrared afterglow, and our failure to detect the optical afterglow, we determine the photometric redshift of the burst to be z = 6.39 - 0.12 + 0.11 (refs 5-7). Subsequently, it was measured spectroscopically to be z = 6.29 +/- 0.01, in agreement with our photometric estimate. These results demonstrate that GRBs can be used to trace the star formation, metallicity, and reionization histories of the early Universe.

Journal Article↗
PubMed2000

Oral management of patients following oncology treatment: literature review.

Many tumours of the head and neck are treated by clinical oncologists using radiotherapy. This treatment modality is particularly effective in destroying rapidly dividing cells, hence its value in cancer treatment. The tissues of the oral mucosa, the salivary glands and blood vessels can be damaged as the result of radiotherapy treatment. As a result, patients experience unwanted oral effects that have both short and long-term implications. The outlook following treatment for head and neck cancer continues to improve and, as people keep their teeth into later life, dentists will increasingly be expected to address the oral problems that patients experience after radiotherapy. The aim of this article is to review the current literature concerning the implications and management of these oral implications of cancer treatment.

Adult↗
PubMed2000

Platelet transfusion practice during dengue fever epidemic.

Blood components especially platelet concentrates due to their short shelf life are frequently in limited supply. Appropriate use of blood components is required to ensure their availability for needy patients as well as to avoid the unnecessary risk of transfusion-transmitted diseases. Medical audit of blood transfusion practice, which forms an important part of quality assurance programme in a transfusion centre, can provide grounds for improvement in transfusion medicine practice. During the epidemic of dengue fever in Oct., 1996, 1837 patients were admitted as dengue haemorrhagic fever in a teaching hospital in Delhi. Two hundred and eight patients (11.3%) were given platelet transfusions. Retrospective analysis of these platelet transfusions was done. It was observed that in only 52 (25%) out of 208 patients the information on platelet counts was provided. History of active bleeding was obtained only in 65 (31.2%) patients. About 35% patients received unnecessary prophylactic transfusions and during 89% of the transfusion episodes inappropriate dose of platelet concentrate was given. Information regarding post-transfusion recovery could be obtained in only 16.5% of transfusion episodes. The study emphasises the need for development of specific guidelines for transfusion of blood components, constant interaction and co-ordination amongst clinicians and transfusion centre for implementation of these guidelines, and a regular medical audit to review the optimal utilisation of blood components.

Adult↗
PubMed1997

Two-photon photodynamic therapy.

OBJECTIVE: We demonstrate the use of infrared excitation in conjunction with an efficient two-photon absorbing dye and a photosensitizer in photodynamic therapy. SUMMARY BACKGROUND DATA: An efficient two-photon absorbing dye is excited by short infrared (800 nm) laser pulses, which transfer its energy to the photosensitizer and the photosensitizer, in turn, generates the singlet oxygen. METHODS: A new approach to photodynamic cancer therapy based on the strong two-photon absorption of certain newly developed organic molecules. Near infrared pulsed laser light efficiently excites these molecules which, in turn, transfer the energy to the photosensitizer used in photodynamic therapy. RESULTS: A newly synthesized two-photon absorbing dye 4-[N-(2-hydroxyethyl)-N-(methyl) amino phenyl]-4'-(6-hydroxyhexyl sulfonyl)stilbene (APSS), which exhibits a strong two-photon absorption at 800 nm, and upconverted fluorescence at 520 nm, in solution in the presence of a photosensitizer was found to generate singlet oxygen under infrared excitation (800 nm). The generation of singlet oxygen in a reaction system containing two-photon absorbing dye and photosensitizer under infrared excitation has been chemically detected by using ADPA (9,10-anthracenedipropionic acid) as singlet oxygen detector. CONCLUSIONS: The efficient two-photon absorption of certain chromophores can be used to extend photodynamic therapy to the near infrared spectral region. Whereas the photosensitizer itself may not exhibit two-photon absorption, it could be used in conjunction with one of these new chromophores. The chromophores can act as "photon harvesters" whereby they absorb two photons of near infrared light and transfer the energy to the photosensitizer, which can generate singlet oxygen in the presence of atmospheric oxygen.

Absorption↗
PubMed1995

Comparison of pleural fluid cytology and pleural biopsy in the evaluation of pleural effusion.

Pleural fluid cytology and pleural biopsy results were studied in 65 cases of pleural effusion. The efficacy of pleural biopsy in diagnosis of neoplastic and non-neoplastic pleural diseases was compared. Of the 24 cases with confirmatory evidence of cancer, 17(70.8%) has positive cytologic findings in pleural fluid, whereas pleural biopsy was diagnostic in only 13 cases (54.1%). For non-malignant pleural effusion in 41 cases 40(97.5%) has a definite diagnosis (tuberculous pleuritis, acute fibrinous pleuritis or hydatid cyst) which could be made by cytology while only 31(75.6%) out of 41 were diagnosed on pleural biopsy. The study indicates that cytologic evaluation of pleural fluid is more efficaceous in the diagnosis of malignant and non-malignant pleural disease than percutaneous pleural biopsy.

Biopsy, Needle↗
PubMed1993

Blood transfusion services in Delhi.

In 1991, approximately 40% of total blood requirement in Delhi was collected from commercial blood donors. The rest was supplied by voluntary and replacement donations in hospital-based blood banks and by voluntary blood recruiting agency (Indian Red Cross Society). This study analyses the standards of working and quality assurance in 26 blood transfusion centers in Delhi. The majority of these centers are ill-equipped and lack trained manpower. Most of these do not have adequate testing facilities and any standardized procedure for blood collection. Quality assurance scheme is not being followed and documentation and record maintenance is grossly inadequate. This reports also gives the recommendations for improvements of blood transfusion services in Delhi.

Blood Banks↗
PubMed1993

Anaphylactoid transfusion reaction with anti-IgA antibodies in an IgA deficient patient: a case report.

A case of anaphylactoid transfusion reaction associated with anti-IgA antibodies is reported. The patient had low levels of serum IgA. She developed serious reaction characterised by erythematous rash, pruritus, cyanosis and dyspnoea after transfusion of otherwise compatible blood. Review of literature reveals that anaphylactoid transfusion reactions are very rare although frequency of anti-IgA in general population is quite high. The IgA deficient donors (aIgA) form a unique resource of blood components for the clinical management of patients with anaphylactoid reactions caused by anti-IgA.

Adult↗
PubMed1992

Nucleolar organizer regions in FNAC smears of breast lesions.

The argyrophil technique for staining proteins associated with nucleolar organizing regions was applied to the fine-needle aspiration cytology smears of 45 cases of breast disease. These included 14 malignant and 31 benign lesions. A correlation with histology sections was done in 12 cases. There was a significant difference between AgNOR count of benign and malignant breast disease with one case out of 45 falling in the "gray" zone of overlap. Infiltrating lobular carcinoma was found to have the lowest NOR counts among the malignant lesions. The smear staining was superior to that on sections, the positive features being lack of background staining and better dispersion of NORs in the nucleoli.

Biopsy, Needle↗
PubMed1990

Aspiration cytology of hemangiopericytoma: a report on two cases.

The cytological features of fine-needle aspiration in two cases of hemangiopericytoma are described. The diagnosis was confirmed by cell block and the silver impregnation method, demonstrating reticulin fibers on smears as well as on the cell block. Histopathological correlation was done in both cases.

Adult↗
PubMedDate not supplied

Fine needle aspiration cytodiagnosis of subcutaneous sacrococcygeal myxopapillary ependymoma. A case report.

A tumor located subcutaneously over the coccyx of a 32-year-old woman was diagnosed by fine needle aspiration (FNA) cytology as a myxopapillary ependymoma originating in the soft tissue. The FNA smears showed characteristic papillary structures, consisting of a central mucinous core surrounded by cuboidal-to-columnar cells, and scattered ependymal cells. The excised tumor was connected to neither the filum terminale nor the cauda equina. Histopathologic study confirmed the cytologic findings.

Adult↗