Biomedical subjects

W G Watson

Publications and source records attributed to W G Watson.

At least 19 recordsLinked to original sources

PubMed1996

Exudative neutrophils show impaired pH regulation compared with circulating neutrophils.

OBJECTIVE: To investigate the effects of neutrophil (PMN) transmigration into inflammatory sites on cytosolic pH (pHi) regulation. DESIGN: Exudative PMNs were obtained by bronchoalveolar lavage from rats sustaining endotoxin-induced lung injury. Circulating PMNs were purified with density-gradient centrifugation. Cytosolic pH was measured with single-cell fluorescence imaging using the pH-sensitive dye biscarboxyethyl-carboxyfluorescein. RESULTS: Exudative PMNs showed impaired pHi recovery from an induced acid load compared with circulating PMNs. Under conditions of extracellular acidosis, exudative PMNs showed impaired pHi homeostasis and produced decreased superoxide compared with circulating cells. Inhibition of the sodium-proton exchanger attenuated the differences in pHi recovery, suggesting a mechanism underlying the pHi regulatory dysfunction. All cells had comparable adenosine triphosphate levels and superoxide production at physiologic extracellular pH. CONCLUSION: Impaired pHi regulation of exudative cells may mediate cellular dysfunction and impaired resolution of infection at inflammatory sites.

Acidosis↗

PubMed1995

The beneficial effects of immunostimulation in posttraumatic sepsis.

Granulocyte macrophage-colony stimulating factor (GM-CSF) is a myelopoietic cytokine that may enhance immune mechanisms directed against bacterial infection. Injury is associated with an increased incidence of such infection. This study assessed the potential immunostimulatory role of GM-CSF in the injured host predisposed to infection. Six- to eight-week old female CD-1 mice underwent trauma and were then randomized to received either GM-CSF or saline vehicle control intraperitoneally for 5 days. They then received a septic challenge in the form of a cecal ligation and puncture. Following this, assessment was made of survival and bacterial growth indices in blood cultures, and peritoneal cells were harvested for assessment of peritoneal immune function. Intraperitoneal GM-CSF administration daily for 5 days following injury was associated with significantly greater survival following cecal ligation and puncture compared to controls (40 vs 5%, P < 0.05). There was a significant increase in peritoneal cell yields in the GM-CSF group compared to the control group (11 +/- 1 x 10(6) vs 8 +/- 1 x 10(6) P < 0.05). PMA-stimulated macrophages released significantly higher amounts of both superoxide anion (1.4 +/- 0.1 vs 0.93 +/- 0.1, P < 0.05) and tumor necrosis factor (5.2 +/- 0.6 vs 2.6 +/- 0.7, P < 0.03) and significantly less nitric oxide compared to the control group (175 +/- 8 vs 267 +/- 24, P < 0.003). Finally, bacterial growth indices were significantly reduced following GM-CSF administration (194 +/- 6 vs 218 +/- 4, P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adjuvants, Immunologic↗

PubMed1992

Human liver dehydroepiandrosterone sulfotransferase: molecular cloning and expression of cDNA.

Sulfation is an important pathway in the metabolism of many hormones and drugs. Human liver contains at least three well characterized sulfotransferase (ST) enzymes, i.e., dehydroepiandrosterone (DHEA) ST and two forms of phenol sulfotransferase (PST). Our goal was to purify, to obtain partial amino acid sequence for, and to clone and express cDNA for human liver DHEA ST. Polymerase chain reaction primers were designed on the basis of homology among rat liver hydroxysteroid ST, rat liver PST, and bovine estrogen ST. These primers amplified a unique sequence from human liver cDNA, and this polymerase chain reaction product was used to screen a human liver cDNA library. Two clones were isolated that contained identical open reading frames, of 855 nucleotides, that encoded a protein of 285 amino acids. The deduced amino acid sequence of the encoded protein included two separate 27- and 23-amino acid sequences that were identical to those obtained by microsequencing of proteolytic fragments from purified human liver DHEA ST. Translation, in a rabbit reticulocyte lysate system, of mRNA transcribed in vitro from the two cDNA clones resulted in a 35-kDa translation product that comigrated with purified human liver DHEA ST during sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This translation product also catalyzed the sulfation of DHEA but not the sulfation of model substrates for the two forms of PST found in human liver. The two cDNA clones were also used to create expression constructs with the eukaryotic expression vector P91023(B), and these constructs were used to transfect COS-1 cells. The transfected cells expressed a high level of DHEA ST activity, and this enzyme activity displayed a pattern of inhibition by the ST inhibitor 2,6-dichloro-4-nitrophenol identical to that of human liver DHEA ST. Cloning of cDNA for this important human sulfate-conjugating enzyme will enhance understanding of the relationship between DHEA ST and other human liver STs, as well as ST enzymes in other species.

Amino Acid Sequence↗

PubMed1985