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Biomedical subjects

R Pandey

Publications and source records attributed to R Pandey.

At least 109 records · Page 6Linked to original sources
PubMed1993

Actinomycosis mimicking carcinoma of the maxillary sinus.

Human actinomycosis may pose a diagnostic problem at times and is often mistaken for a neoplasm. A thirty-five year old male was clinically diagnosed as a case of carcinoma of the right maxillary sinus on the basis of history, clinical presentation and radiologic findings. Tissue biopsy was negative for malignancy on three consecutive occasions. Microscopic examination showed bits of granulation tissue and fragments of filamentous structures. On microbiological examination, Actinomyces israelii was isolated and fungus culture was negative. Long term Penicillin treatment caused disappearance of all signs and symptoms. The report highlights the importance of bearing in mind the fact that certain rare, chronic, suppurative granulomatous infections, like actinomycosis, may mimic malignancy.

Actinomycosis, Cervicofacial↗
PubMed1992

Biologically selected recombinants between feline leukemia virus (FeLV) subgroup A and an endogenous FeLV element.

In efforts to elucidate the proximal leukemogens that might be produced during a feline leukemia virus (FeLV) infection of cats, homologous recombinations between molecularly cloned exogenous and endogenous FeLV proviruses of known sequences were examined in cell cultures in vitro. A plasmid containing an infectious member of the most commonly occurring FeLV subgroup (FeLV subgroup A or FeLV-A) was coexpressed with noninfectious constructs containing the envelope (env) gene of an endogenously inherited FeLV-like feline genomic element in transfected feline fibroblasts. The viruses generated were selected for their ability to propagate in human cells which are resistant to infection by the parental ecotropic FeLV-A or the noninfectious endogenous constructs. An analysis of the recombinants thus derived identified a limited number of sites in the env gene which were preferentially utilized in the generation of recombinant FeLVs under the selection conditions used. These sites were clustered in the surface glycoprotein (SU) moiety of the env gene, and it appeared that most, but not all, of the SU gene product of FeLV-A, beginning from the N-terminus, can be replaced by sequences from an endogenous element, still allowing the virus to be biologically viable. In fact, these substitutions in the env gene expanded infectivity of the parental FeLV-A from ecotropic to polytropic cell tropism. Additionally, substitutions in the SU region yielded many recombinants in which a primary neutralizing pentapeptide epitope of FeLV-A was altered because of its variance in the endogenous element. In several of the recombinants, this sequence was also found to be frequently mutated. Consistent with the changes identified in this antibody-binding domain, the recombinant viruses were only weakly inhibited by a monoclonal antibody directed against this epitope, while FeLV-A was highly sensitive to neutralization.

Amino Acid Sequence↗
PubMed1992

Exposed eye area (EEA) in the expression of various emotions.

Exposed eye area (EEA) was measured in photographs of Indian adults who modeled six emotions--happiness, sadness, fear, anger, surprise, and disgust--as well as a neutral expression. The data were analyzed with a 2 x 6 (Eyes x Emotions) factorial analysis of covariance (ANCOVA). EEA for neutral expression was used as the covariate measure. The EEAs of the two eyes did not differ significantly during the expression of emotion. The EEAs for fear and surprise were significantly larger, and the EEA for disgust was significantly smaller than those for either other emotions or neutral expression.

Adult↗
PubMed1992

Explosive Campylobacter jejuni diarrhea in immunoproliferative small intestinal disease.

Campylobacter jejuni is an infrequent cause of self limiting acute diarrheal disease in adults in the Indian subcontinent. We report the occurrence of a life threatening diarrhea due to C jejuni infection in a patient with immunoproliferative small intestinal disease. We postulate that immunosuppression due to malignancy, malnutrition and cancer chemotherapy was responsible for the unusually severe diarrhea.

Adult↗
PubMed1992

Cultures of human retinal pigment epithelium. Modulation of extracellular matrix.

The extracellular matrix of retinal pigment epithelial (RPE) cells is an important component of the fibroelastic membranes formed in proliferative vitreoretinopathy (PVR). These membranes consist of cells intermingled with fibrillar proteins, such as elastin and collagen. Because RPE cells may be exposed to vitreous and serum-derived factors in conditions that lead to PVR, the effects of vitreous and serum on the deposition of fibrillar proteins by RPE cells were studied using radioactive labeling and indirect immunofluorescence techniques. The RPE cells, modulated by combined vitreous and serum into a fibrocytic-like appearance, deposited less fibroelastic proteins per cell. However, as a result of simultaneous cell proliferation, the total deposition of fibroelastic proteins per culture was increased. Indirect immunofluorescence studies suggest that it is type I collagen that is altered in the matrix of these modulated cell cultures. This information is important in pathologic conditions characterized by intraocular cell proliferation and fibroelastic membrane formation; these phenomena are seen in many vitreoproliferative disorders.

Cell Count↗
PubMed1991

Recombination between feline leukemia virus subgroup B or C and endogenous env elements alters the in vitro biological activities of the viruses.

An important question in feline leukemia virus (FeLV) pathogenesis is whether, as in murine leukemia virus infection, homologous recombination between the infecting FeLV and the noninfectious endogenous FeLV-like proviruses serves as a significant base for the generation of proximal pathogens. To begin an analysis of this issue, several recombinant FeLVs were produced by using two different approaches: (i) the regions of the viral envelope (env) gene of a cloned FeLV (subgroup B virus [FeLV-B], Gardner-Arnstein strain) and those of two different endogenous proviral loci were exchanged to create specific FeLV chimeras, and (ii) vectors containing endogenous env and molecularly cloned infectious FeLV-C (Sarma strain) DNA sequences were coexpressed by transfection in nonfeline cells to facilitate recombination. The results of these combined approaches showed that up to three-fourths of the envelope glycoprotein (gp70), beginning from the N-terminal end, could be replaced by endogenous FeLV sequences to produce biologically active chimeric FeLVs. The in vitro replication efficiency or cell tropism of the recombinants appeared to be influenced by the amount of gp70 sequences replaced by the endogenous partner as well as by the locus of origin of the endogenous sequences. Additionally, a characteristic biological effect, aggregation of feline T-lymphoma cells (3201B cell line), was found to be specifically induced by replicating FeLV-C or FeLV-C-based recombinants. Multiple crossover sites in the gp70 protein selected under the conditions used for coexpression were identified. The results of induced coexpression were also supported by rapid generation of FeLV recombinants when FeLV-C was used to infect the feline 3201B cell line that constitutively expresses high levels of endogenous FeLV-specific mRNAs. Furthermore, a large, highly conserved open reading frame in the pol gene of an endogenous FeLV provirus was identified. This observation, particularly in reference to our earlier finding of extensive mutations in the gag gene, reveals a target area for potentially productive homologous recombination upstream of the functional endogenous env gene.

3T3 Cells↗
PubMed1990

Influence of sleep on lung volume in asthmatic patients and normal subjects.

To assess the effect of sleep on functional residual capacity (FRC) in normal subjects and asthmatic patients, 10 adult subjects (5 asthmatic patients with nocturnal worsening, 5 normal controls) were monitored overnight in a horizontal volume-displacement body plethysmograph. With the use of a single inspiratory occlusion technique, we determined that when supine and awake, asthmatic patients were hyperinflated relative to normal controls (FRC = 3.46 +/- 0.18 and 2.95 +/- 0.13 liters, respectively; P less than 0.05). During sleep FRC decreased in both groups, but the decrease was significantly greater in asthmatic patients such that during rapid-eye-movement (REM) sleep FRC was equivalent between the asthmatic and normal groups (FRC = 2.46 +/- 0.23 and 2.45 +/- 0.09 liters, respectively). Specific pulmonary conductance decreased progressively and significantly in the asthmatic patients during the night, falling from 0.047 +/- 0.007 to 0.018 +/- 0.002 cmH2O-1.s-1 (P less than 0.01). There was a significant linear relationship through the night between FRC and pulmonary conductance in only two of the five asthmatic patients (r = 0.55 and 0.65, respectively). We conclude that 1) FRC falls during sleep in both normal subjects and asthmatic patients, 2) the hyperinflation observed in awake asthmatic patients is diminished during non-REM sleep and eliminated during REM sleep, and 3) sleep-associated reductions in FRC may contribute to but do not account for all the nocturnal increase in airflow resistance observed in asthmatic patients with nocturnal worsening.

Adult↗
PubMed1990

Effect of sleep and sleep deprivation on ventilatory response to bronchoconstriction.

To characterize ventilatory responses to bronchoconstriction during sleep and to assess the effect of prior sleep deprivation on ventilatory and arousal responses to bronchoconstriction, bronchoconstriction was induced in eight asthmatic subjects while they were awake, during normal sleep, and during sleep after a 36-h period of sleep deprivation. Each subject was bronchoconstricted with increasing concentrations of aerosolized methacholine while ventilatory patterns and lower airway resistance (Rla) were continually monitored. The asthmatic patients maintained their minute ventilation as Rla increased under all conditions, demonstrating a stable tidal volume with a mild increase in respiratory frequency. Inspiratory drive, as measured by occlusion pressure (P0.1), increased progressively and significantly as Rla increased under all conditions (slopes of P0.1 vs. Rla = 0.249, 0.112, and 0.154 for awake, normal sleep, and sleep after sleep deprivation, respectively, P less than 0.0006). Chemostimuli did not appear to contribute significantly to the observed increases in P0.1. Prior sleep deprivation had no effect on ventilatory and P0.1 responses to bronchoconstriction but did significantly raise the arousal threshold to induced bronchoconstriction. We conclude that ventilatory responses to bronchoconstriction, unlike extrinsic loading, are not imparied by the presence of sleep, nor are they chemically mediated. However, prior sleep deprivation does increase the subsequent arousal threshold.

Adult↗