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Biomedical subjects

G K Davis

Publications and source records attributed to G K Davis.

At least 37 records · Page 2Linked to original sources
PubMed1999

The origin and evolution of segmentation.

Arthropods, annelids and chordates all possess segments. It remains unclear, however, whether the segments of these animals evolved independently or instead were derived from a common ancestor. Considering this question involves examining not only the similarities and differences in the process of segmentation between these phyla, but also how this process varies within phyla, where the homology of segments is generally accepted. This article reviews what is known about the segmentation process and considers various proposals to explain its evolution.

Animals↗
PubMed1997

Molecular genetics of the renin-angiotensin system: implications for angiotensin II receptor blockade.

Angiotensin II (Ang II) is the main effector hormone of the renin-angiotensin system (RAS). The pathogenesis of many cardiovascular diseases, including heart failure and hypertension, appear to be related to Ang II production. The generation of Ang II involves angiotensin-converting enzyme (ACE) in circulating and tissue RAS's, as well as non-ACE pathways. ACE and other components of the RAS show natural mutations. In this review, we discuss the molecular genetics of the human RAS in relation to cardiovascular disease, including the clinical effects of known ACE molecular variants and possible pharmacological treatment strategies.

Angiotensin II↗
PubMed1994

Determination of the hemodynamics and histamine release of rocuronium (Org 9426) when administered in increased doses under N2O/O2-sufentanil anesthesia.

The cardiovascular effects, histamine release potential, and pharmacodynamics of rocuronium were determined in adult patients randomized to receive rapid (5 s) intravenous (i.v.) bolus doses of 600, 900, or 1200 micrograms/kg (2.0, 3.0, and 4.0 times the ED95) with maintenance doses of 150 micrograms/kg. There were no statistically significant hemodynamic effects (heart rate, blood pressure, mean arterial pressure [MAP] or electrocardiogram [ECG]) after administration of rocuronium. There were no increases in plasma histamine levels at 1, 3, and 5 min after the rapid i.v. bolus of rocuronium as determined by a new radioimmunoassay (RIA) with a sensitivity for histamine quantification of 0.05 ng/mL. Endotracheal intubation was successfully performed 6 min after rocuronium administration (and after plasma samples were obtained). The mean +/- SD clinical durations of 600-, 900-, and 1200-micrograms/kg intubating doses of rocuronium under N2O/O2-sufentanil anesthesia were 45 +/- 20 min, 66 +/- 16 min, and 85 +/- 22 min, respectively. We conclude that rocuronium can be administered safely over a wide range of doses (2-4 x ED95), with minimum hemodynamic effects or histamine release.

Adult↗
PubMed1990

Structural cardiac abnormalities in the fetus: reliability of prenatal diagnosis and outcome.

The outcomes of 129 pregnancies in which the fetus was found to have a structural cardiac abnormality are reviewed. Over a 30-month period from January 1985 to June 1987, 1924 patients were referred to the British Heart Foundation Research Centre for Perinatal Cardiology at Guy's Hospital for fetal cardiac scanning. A total of 129 structural cardiac abnormalities was diagnosed; 53% of these patients were referred because of an abnormal 'four-chamber view' on ultrasound at the referring hospital; 47 of the pregnancies (69% of the 68 patients referred before 28 weeks) were terminated, and in the remaining 82 pregnancies outcome was poor with only 20 infants (16%) surviving longer than 11 months. The prenatal diagnosis was fully or partly correct in 96% of the 111 cases where it was possible to verify the diagnosis by post-mortem or postnatal diagnosis. In the 82 pregnancies not terminated, 13 of the 22 cases given a moderate or good prognosis survived more than 11 months (59% survival), but only seven of the 60 (12% survival) given a fatal, poor or uncertain prognosis. The benefits of a multidisciplinary approach are discussed.

Chromosome Aberrations↗
PubMed1981

Fecal bulk, energy intake, and serum cholesterol: regression response of serum cholesterol to apparent digestibility of dry matter and suboptimal energy intake in rats on fiber-fat diet.

Two experiments were conducted in the rat to determine the relationships of serum cholesterol (SC, mg/dl), apparent digestibility of dry matter (DDM, %), and digested energy intake (DE, kcal/day) at suboptimal level of energy. The energies in diet and feces were determined by calorimetry. DE as percentage of the National Research Council requirement (DE%) was suboptimal (70 to 85%). The experiments had four to five isofibrous diets, and no fiber diets, supplemented with 0.2% crystalline cholesterol (CChol). Animals in experiment 1 were fed varying amounts of feed with 18% coconut oil in the diets where as these in experiment 2 were given fixed amounts of feed with either 6 or 18% oil. The following regressions (p less than 0.001) for SC were found: experiment 1: -1157.7 -5.97 DDM +105.5 CCI -1.48 CCI2 (r2 0.35), where CCI = CChol, mg/day; -1888.4 -2.66 DE +120.97 CCI -1.62 CCI2 (r2 0.37). Experiment 2: 762.99 -6.15 DDM -0.8 fat cal % -0.87DE% (r2 0.31), where fat cal % = fat calories % of DE. Data indicate that at suboptimal energy intake, SC was inversely related to (1) DDM, (2) fat cal, and (3) total energy intake. Liver cholesterol lowering effect of the dietary fiber was also observed. The above findings help to elucidate various conflicting reports related to diet and blood cholesterol.

Animals↗