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Biomedical subjects

H Ghosh

Publications and source records attributed to H Ghosh.

7 recordsLinked to original sources

Ultrafast optical nonlinearity in the quasi-one-dimensional mott insulator Sr2CuO3

We report strong instantaneous photoinduced absorption in the quasi-one-dimensional Mott insulator Sr2CuO3 in the IR spectral region. The observed photoinduced absorption is to an even-parity two-photon state that occurs immediately above the absorption edge. Theoretical calculation based on a two-band extended Hubbard model explains the experimental features and indicates that the strong two-photon absorption is due to a very large dipole coupling between nearly degenerate one- and two-photon states. Room temperature picosecond recovery of the optical transparency suggests the strong potential of Sr2CuO3 for all-optical switching.

Journal Article↗

Causes of hospital-acquired septicaemia--a case control study.

Hospital-acquired septicaemia is common and an important cause of morbidity and expense. Few studies have explored its cause by comparing features of people who do and do not develop septicaemia--the aim of this study. All blood cultures were monitored over one year in a 400-bed tertiary care hospital where special care is taken with intravenous cannulae to prevent septicaemia. Cases had at least one positive blood culture taken at least 48 h after admission. The nearest two patients in the same ward were controls, and information was abstracted on all three from the hospital records by a research nurse. There were 84 cases during the 12 months (3.8 per 1000 admissions) and 167 controls. Univariate odds ratios (95% CI) were 5.57 (2.06-15.95) with the presence of a central venous line, 3.40 (1.16-16.40) with total parenteral nutrition, 2.41 (1.30-4.32) with blood transfusion, 2.10 (1.16-4.56) with immunosuppressive disease, 2.06 (1.02-4.44) with the presence of a urinary catheter and 0.32 (0.17-0.69) with recent surgery. Conditional logistic regression identified a central venous line and blood transfusion to be independent risk factors for septicaemia, odds ratios (and 95% CI) being 5.14 (1.74-15.23) and 2.74 (1.28-5.88), respectively, while recent surgery and antibiotic prophylaxis were independently 'protective' at 0.31 (0.12-0.79) and 0.38 (0.16-0.90), respectively. Thus, in a hospital where great care has been taken to avoid septicaemia, especially by attention to intravenous cannulae, there were only two independent risk factors for the development of hospital-acquired septicaemia--a central venous line and blood transfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Case-Control Studies↗

Identification and characterization of a novel herpes simplex virus glycoprotein, gK, involved in cell fusion.

Antipeptide sera were used to identify a novel glycoprotein encoded by the UL53 gene of herpes simplex virus type 1 (HSV-1). The UL53 gene product is thought to play a central role in regulating membrane fusion because mutations giving rise to the syncytial phenotype, wherein cells are extensively fused, frequently map to this gene. A single 40-kDa protein, designated gK (the ninth HSV-1 glycoprotein to be described), was detected with antipeptide sera in cells infected with both wild-type and syncytial strains of HSV-1 which were labelled with [35S]methionine and [35S]cysteine or with [3H]glucosamine, and this protein was sensitive to treatment of cells with tunicamycin. With all other HSV glycoproteins studied to date, at least two glycosylated species, often differing substantially in electrophoretic mobility, have been observed in infected cells; thus, gK is unusual in this respect. The 40-kDa gK protein was also immunoprecipitated from cells infected with a recombinant adenovirus vector carrying the UL53 gene. Two glycosylated species of 39 and 41 kDa were produced when UL53 mRNA was translated in vitro in the presence of microsomes, and these proteins differed from gK produced in infected cells not only because they possessed different electrophoretic mobilities but also because they were unable to enter gels after being heated. In addition, a 36-kDa protein was detected in extracts from cells infected with HSV-2 with use of these sera.

Adenoviridae↗

Identification of gallbladder typhoid carriers by a string device.

The efficiency of a gelatin capsule containing a nylon string for collection of duodenal specimens was investigated in carriers of Salmonella typhosa (typhi). Cultures of duodenal specimens obtained by means of the string capsule were compared with cultures of duodenal specimens obtained by a conventional duodenal tube and with stool cultures Duodenal contents obtained with either the string or tube were more often positive for S. typhosa than were stool cultures. The string, which is as efficient as tube collection but simpler and more comfortable, may be useful in identifying carriers of S. typhosa.

Adult↗