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Biomedical subjects

J R Wood

Publications and source records attributed to J R Wood.

At least 19 recordsLinked to original sources
PubMed1992

Functional homologs of the Arabidopsis RPM1 disease resistance gene in bean and pea.

We showed that a bacterial avirulence (avr) gene function, avrPpiA1, from the pea pathogen Pseudomonas syringae pv pisi, is recognized by some, but not all, genotypes of Arabidopsis. Thus, an avr gene functionally defined on a crop species is also an avr gene on Arabidopsis. The activity of avrPpiA1 on a series of Arabidopsis genotypes is identical to that of the avrRpm1 gene from P.s. pv maculicola previously defined using Arabidopsis. The two avr genes are homologous and encode nearly identical predicted products. Moreover, this conserved avr function is also recognized by some bean and pea cultivars in what has been shown to be a gene-for-gene manner. We further demonstrated that the Arabidopsis disease resistance locus, RPM1, conditioning resistance to avrRpm1, also conditions resistance to bacterial strains carrying avrPpiA1. Therefore, bean, pea, and conceivably other crop species contain functional and potentially molecular homologs of RPM1.

Amino Acid Sequence↗
PubMed1992

The effect of combined therapy with ranitidine and pirenzepine in the treatment of reflux oesophagitis.

The combination of a histamine H2-receptor antagonist and a muscarinic receptor antagonist has been reported to result in greater suppression of intragastric acidity than either agent alone. The present randomized, double-blind, multicentre trial compared the effects of the oral combination of 150 mg ranitidine b.d. plus 50 mg pirenzepine b.d. with 150 mg ranitidine b.d. plus placebo pirenzepine b.d. in the treatment of patients with reflux oesophagitis. All 157 patients had symptoms of gastro-oesophageal reflux with endoscopically confirmed oesophageal erosions (Savary and Miller grades I-III). After four weeks of treatment, healing rates were 32/75 (43%) in the combined treatment group and 34/76 (45%) in the group receiving ranitidine alone. After eight weeks, the cumulative healing rates had increased to 48/72 (67%) and 51/75 (68%), respectively. More patients receiving ranitidine plus pirenzepine had complete relief of day- and night-time heartburn after four weeks compared with those receiving ranitidine alone (day: 59% vs. 38%, P = 0.02; night: 69% vs. 52%, P = 0.04). After eight weeks, symptom relief was comparable in both groups. Clinical adverse effects were reported by nine patients receiving ranitidine and by 19 patients receiving the combination. It is concluded that combining ranitidine with pirenzepine does not aid the healing of reflux oesophagitis but does improve symptom relief at four weeks.

Administration, Oral↗
PubMed1979

Animal maturity influences prostaglandin effects on gallbladder fluid transport and smooth muscle.

Prostaglandin (PG) A, E and F compounds applied serosally inhibited net fluid absorption and increased intraluminal pressure in guinea-pig isolated gallbladder. The inhibition was dose-dependent for a given animal body weight but sensitivity varied inversely with animal body weight; relative potencies were PGE2 greater than F2alpha greater than A1. In heavier animals the inhibition was preceded by an apparent increase in fluid absorption, due to fluid extrusion following muscle contraction. Net fluid secretion was observed at higher concentrations of PGE2 or F2alpha in lighter animals. Mucosally applied PGs less potently inhibited absorption, with relative potencies of PGE2 greater than A1 greater than F2beta greater than F2alpha. The spasmogenic effect was estimated by measuring intraluminal pressure (PGE2 greater than F2alpha greater than A1).

Aging↗
PubMed1979

Effects of bicarbonate on fluid and electrolyte transport by the guinea pig gallbladder: a bicarbonate-chloride exchange.

Fluid transport and net fluxes of Na, K, Cl and HCO3 by guinea pig gallbladder were investigated in vitro. A perfused gallbladder preparation was devised to simultaneously study unidirectional fluxes of 22Na and 36Cl. The net Cl flux exceeded the net Na flux during fluid absorption in the presence of HCO3. This Cl excess was counterbalanced by a net HCO3 secretion: a HCO3-Cl exchange. PGE1 reversed the direction of fluid transport and abolished the net Cl flux. The magnitude of the HCO3 secretion remained unchanged, but shifted from a HCO3-Cl exchange to a net secretion of NaHCO3 and KHCO3. Furosemide inhibited both the HCO3-Cl exchange and HCO3 secretion after PGE1 without influencing fluid absorption. Ouabain inhibited the HCO3-Cl exchange as well as fluid absorption; only the effect on the HCO3 secretion was entirely reversible. Secreted HCO3 appeared not to be derived from metabolic sources since HCO3 secretion was abolished in a HCO3-free bathing medium. HCO3 secretion was also dependent on the Na concentration of the bathing fluid. Three lines of evidence are presented in favor of an active HCO3 secretion in guinea pig gallbladder. HCO3 is secreted against: (i) a chemical gradient, (ii) an electrical gradient and (iii) the direction of fluid movement under control conditions.

Absorption↗
PubMed1977

Prostaglandins in chronic cholecystitis.

Prostaglandin-like material was extracted from the mucosa and muscle wall of chronically inflamed human gallbladders. Bioassays showed that "synthesised" levels were 3-5 times corresponding "basal" levels, indicating that both mucosa and muscle wall can synthesise PG-like substances, and that indomethacin (10 mug/ml) inhibited this synthesis. Mucosal PG levels were higher in gallbladders with multiple gallstones than with a solitary stone, and overall the mean PG level in mucosa was 12-13 times higher than in the muscle wall. Chromatography of mucosal extracts showed substances indistinguishable from primary PGE and F compounds together with a PGD2-like component. An attempt has been made to relate these findings to the degree of chronic inflammatory cell infiltration and to radiological visualisation at pre-operative cholecystography.

Adult↗
PubMed1977

Quantitative requirements of the hatchling green sea turtle for lysine, tryptophan, and methionine.

The quantitative requirement for the amino acids lysine, tryptophan, and methionine was determined for the hatchling green sea turtle (Chelonia mydas). Hatchling green sea turtles were fed synthetic diets of purified substances with the composition of the diet varying in the amount of lysine, tryptophan or methionine present. The lysine requirement was found to be 4.8% of the crude protein (N X 6.25) or 1.7% of the dry diet. The tryptophan requirement was found to be 0.63% of the crude protein or 0.22% of the dry diet. The methionine requirement, in the presence of adequate cystine (3.1% of the crude protein), was found to be 1.5% of the crude protein or 0.49% of the dry diet.

Animals↗
PubMed1977

Quantitative requirement of the hatchling green sea turtle, Chelonia mydas, for valine, leucine, isoleucine and phenylalanine.

Hatchling green sea turtles were fed purified diets containing 36% crude protein (N X 6.25) to determine the quantitative requirements for valine, leucine, isoleucine and phenylalanine. Expressed as percentage of total dry diet, the hatchling green sea turtle requires 1.3% valine, 1.6% leucine, 1.0% isoleucine and 1.0% phenylalanine (in the presence of 0.5% tyrosine). Within the range of isoleucine-leucine levels investigated, there was no apparent interrelationship between the quantitative requirements of these two amino acids. Growth rate was decreased at a high level of phenylalanine, 3.0% of the dry diet.

Animals↗
PubMed1976

Facial fractures.

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Facial Injuries↗