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Biomedical subjects

Kenneth Watson

Publications and source records attributed to Kenneth Watson.

9 recordsLinked to original sources

Intratracheal pulmonary ventilation improves gas exchange during laparoscopy in a pediatric lung injury model.

BACKGROUND/PURPOSE: This study was aimed at determining whether intraoperative intratracheal pulmonary ventilation (ITPV) could prevent/treat respiratory complications of laparoscopy in a model of pediatric pulmonary insufficiency. METHODS: Severe lung injury was induced in 0- to 2-month-old lambs (n = 5) by endotracheal saline lavage. Animals then underwent establishment of CO2 pneumoperitoneum. Intraperitoneal pressures were progressively raised from 0 to 15 mm Hg, at intervals of 5 mm Hg. At each interval, blood gas and hemodynamic data were recorded, 20 minutes after initiation of both conventional ventilation and pure ITPV. All ventilatory parameters were constant and identical on both modes of ventilation. RESULTS: On conventional ventilation, severe respiratory acidosis and hypoxemia ensued at intraperitoneal pressures of 5 mm Hg and 10 mm Hg or more, respectively. Compared with conventional ventilation, ITPV led to statistically significant decreases in PCO2 at intraperitoneal pressures of 5 mm Hg (43.2 +/- 5.2 vs 56.1 +/- 6.6 mm Hg) and 10 mm Hg (45.1 +/- 3.2 vs 61 +/- 6.3 mm Hg) and to significant increases in PO2 at 10 mm Hg (92 +/- 10.2 vs 61 +/- 8.1 mm Hg), resolving the acidosis and hypoxemia at those pressure levels. CONCLUSIONS: Compared with conventional ventilation, ITPV improves both CO2 removal and oxygenation during CO2 pneumoperitoneum in a pediatric lung injury model. Intratracheal pulmonary ventilation may be a safer intraoperative mode of ventilation for neonates and children with respiratory failure who require laparoscopy.

Acidosis, Respiratory↗

A novel psychrotolerant member of the hymenomycetous yeasts from Antarctica: Cryptococcus watticus sp. nov.

Soil, snow and organic material, collected in November 1997 from the Vestvold Hills, Davis Base, Antarctica, were screened for yeasts. Two isolates, which were shown to be indistinguishable by rDNA sequencing and protein analysis by SDS-PAGE, are described in this communication as a novel species, Cryptococcus watticus sp. nov. (type culture, CBS 9496T=NRRL Y-27556T). Sequence analyses of the 26S rDNA D1/D2 region placed C. watticus in the hymenomycetous yeasts in a cluster with Holtermannia corniformis and Cryptococcus nyarrowii. This species has been allocated to the genus Cryptococcus on the basis of physiological and morphological characteristics.

Antarctic Regions↗

Altered lymphocyte heat shock protein 70 expression in patients with HIV disease.

Heat shock protein (HSP) expression in lymphocytes isolated from 20 patients with HIV disease and 15 age-matched controls was determined. Fold increases in lymphocyte hsp70 expression after heat shock were 4.52 +/- 2.97 in HIV-positive individuals compared with 2.60 +/- 1.29 for HIV-negative controls (P= 0.001). Given clear roles for HSP in the cross-presentation of antigens, alpha-defensin internalization and pro-inflammatory cytokine production, a further investigation of HSP in HIV patients is merited.

Adult↗

Influence of ageing, heat shock treatment and in vivo total antioxidant status on gene-expression profile and protein synthesis in human peripheral lymphocytes.

Ageing results in a progressive, intrinsic and generalised imbalance of the control of regulatory systems. A key manifestation of this complex biological process includes the attenuation of the universal stress response. Here we provide the first global assessment of the ageing process as it affects the heat shock response, utilising human peripheral lymphocytes and cDNA microarray analysis. The genomic approach employed in our preliminary study was supplemented with a proteomic approach. In addition, the current study correlates the in vivo total antioxidant status with the age-related differential gene expression as well as the translational kinetics of heat shock proteins (hsps). Most of the genes encoding stress response proteins on the 4224 element microarray used in this study were significantly elevated after heat shock treatment of lymphocytes obtained from both young and old individuals albeit to a greater extent in the young. Cell signaling and signal transduction genes as well as some oxidoreductases showed varied response. Results from translational kinetics of induction of major hsps, from 0 to 24 h recovery period were broadly consistent with the differential expression of HSC 70 and HSP 40 genes. Total antioxidant levels in plasma from old individuals were found to be significantly lower by comparison with young, in agreement with the widely acknowledged role of oxidant homeostasis in the ageing process.

Adult↗

Cryptococcus nyarrowii sp. nov., a basidiomycetous yeast from Antarctica.

In December 1997, 196 soil and snow samples were collected from Vestvold Hills, Davis Base, Antarctica. Two isolates, CBS 8804T (pink colonies) and CBS 8805 (yellow colonies), were shown by proteome analysis and DNA sequencing to represent the same species. Results from the sequencing of the D1/D2 region of the large rDNA subunit placed this species in the hymenomycetous tree in a unique sister clade to the Trichosporonales and the Tremellales. The clade consists of Holtermannia corniformis CBS 6979 and CBS strains 8804T, 8805, 8016, 7712, 7713 and 7743. Morphological and physiological characteristics placed this species in the genus Cryptococcus, with characteristics including the assimilation of D-glucuronate and myo-inositol, no fermentation, positive Diazonium blue B and urease reactions, absence of sexual reproduction and production of starch-like compounds. Fatty acid analysis identified large proportions of polyunsaturated lipids, mainly linoleic (C18:2) and, to a lesser extent, linolenic (C18:3) acids. On the basis of the physiological and phylogenetic data, isolates CBS 8804T and CBS 8805 are described as Cryptococcus nyarrowii sp. nov.

Antarctic Regions↗

Cryptococcus statzelliae sp. nov. and three novel strains of Cryptococcus victoriae, yeasts isolated from Antarctic soils.

A morphological and physiological characterization of yeast strains CBS 8908, CBS 8915, CBS 8920, CBS 8925(T) and CBS 8926, isolated from Antarctic soils, was performed. Phylogenetic analyses of the sequences of the D1/D2 regions and the adjacent internal transcribed spacer (ITS) regions of the large-subunit rDNA of these strains placed them into the Tremellales clade of the Hymenomycetes. The sequence data identified strains CBS 8908, CBS 8915 and CBS 8920 as belonging to the species Cryptococcus victoriae. Strains CBS 8925(T) and CBS 8926 were found to represent an unique clade within the Hymenomycetes, with Dioszegia crocea CBS 6714(T) being their closest phylogenetic relative. Fatty acid composition and proteome fingerprint data for these novel strains were also obtained. No sexual state was observed. A novel basidiomycetous species, Cryptococcus statzelliae, is proposed for strains CBS 8925(T) and CBS 8926.

Antarctic Regions↗

Dietary intake of antioxidant supplements modulate antioxidant status and heat shock protein 70 synthesis.

The physiological effects and efficacy of dietary intake of antioxidant supplements in humans remains controversial. Experiments involving dietary, often high, intake of a single antioxidant or vitamin may be seriously flawed given the interactive nature of antioxidants in vivo. The present studies were conducted on individuals (35-60 years of age) taking a commercial antioxidant mixture in a double-blind, placebo-controlled, cross-over study. Intake was two capsules per day, for 4 weeks, with a 4-week washout period in between active dose or placebo. Intake of antioxidants was associated with little change in superoxide dismutase activity, but an increase in glutathione peroxidase was noted. Haemolysis of red blood cells (erythrocytes) induced by the free radical generator AAPH was significantly reduced in individuals on antioxidant supplements. In lymphocytes isolated from individuals taking supplements, there was a marked increase, as compared with individuals on placebo, in the synthesis of heat shock protein 70 (hsp70) following heat shock from 37 degrees C to 42.5 degrees C. We conclude that dietary intake of a mixed antioxidant supplement leads to modulation of cellular redox status resulting in decreased oxidative stress and increased ability of lymphocytes to mount a stress response.

Adult↗

Resistance to UVB radiation in Antarctic yeasts.

Yeast cells were used as a model system to study the inter-relationship among free radicals, antioxidants and UV-induced cell damage. In particular, the effects of UV-radiation in newly isolated yeasts from the Antarctic have been studied.

Antarctic Regions↗