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Biomedical subjects

G Smith

Publications and source records attributed to G Smith.

At least 793 records · Page 44Linked to original sources
PubMed1982

Effects of morphine on net water absorption, mucosal adenylate cyclase activity and PGE2 metabolism in rat intestine.

Morphine (10 mg/kg s.c.) was shown to increase net basal water and electrolyte absorption in rat ileum and colon perfused in vivo. These effects were significantly greater in the ileum. Under the same conditions of dosage and time course of administration the activities of relevant mucosal enzymes were studied. Ileal mucosal adenylate cyclase stimulated by prostaglandin E2 (PGE2) in vitro was inhibited by morphine pretreatment. Colonic stimulated cyclase activity was unaffected as were basal activities in both regions. Morphine did not alter the activities of enzymes involved in PGE2 metabolism and is unlikely to act by modulating endogenous PG levels. Transport ATPase activities, were also unchanged in morphine treated animals. These results are discussed in relation to the mechanism of action of morphine on intestinal mucosa.

Adenylyl Cyclases↗
PubMed1982

Transforming gene of a human leukaemia cell is unrelated to the expressed tumour virus related gene of the cell.

The virally encoded oncogenes (v-onc) of avian and mammalian retroviruses are the recombinant products of normal cellular genes (c-onc) and a retroviral genome. These cellular homologues have been highly conserved during evolution and are found in human DNA. The expression of at least one c-onc under the control of a viral promoter results in transformation of cells in a manner resembling that displayed by the v-onc counterpart; the inappropriate expression of c-onc in the absence of viral influences could likewise result in the malignant state. This proposal would be strongly supported by the presence of c-onc RNAs in a variety of human tumours were they not also demonstrable in normal tissues. The role of these RNAs in the oncogenic process remains unclear. Here we report that RNA homologous to the oncogene (v-abl) of Abelson murine leukaemia virus (A-MLV) is expressed in a unique human leukaemia in a fashion different from that of other human tissues and tumours. In addition, DNA from this tumour transforms NIH-3T3 cells at a high efficiency in a transfection assay. The transfected sequences are not related to the v-abl gene, but the NIH-3T3 transformants manufacture a transforming growth factor which behaves similarly to factors produced by A-MLV-transformed NIH-3T3 fibroblasts.

Abelson murine leukemia virus↗
PubMed1982

Postoperative analgesia with controlled-release morphine sulphate: comparison with intramuscular morphine.

Fifty patients undergoing hysterectomy or cholecystectomy took part in a trail of postoperative analgesia provided by either intramuscular morphine or controlled-release morphine sulphate tablets orally. Respiratory function and plasma catecholamine concentrations were measured after operation and pain was assessed by using a linear analogue scoring method. Controlled-release morphine sulphate produced comparable pain relief with that of intramuscular morphine, and depression of respiratory function after operation was similar with the two analgesic regimens. The mean total dose of drug per patient given over 48 h to patients undergoing hysterectomy was 115 mg for morphine sulphate and 53 mg for morphine. Patients undergoing cholecystectomy received 130 mg morphine sulphate or 76 mg morphine. There was more sedation after operation in those patients undergoing hysterectomy who received morphine sulphate tablets. Morphine sulphate tablets produced satisfactory postoperative analgesia compared with intramuscular morphine: both regimens were acceptable to the patients.

Adult↗
PubMed1982

Severe hypoglycaemia due to combined use of parenteral nutrition and renal dialysis.

A 24-year-old woman who had sustained serious injuries in a road traffic accident required renal dialysis daily and was fed intravenously with a solution containing 25% dextrose. Subsequently insulin had to be added to the parenteral fluid to maintain blood glucose concentrations at physiological values. On one occasion parenteral feeding was continued until dialysis was started; she became comatose and the plasma glucose concentration was found to be less than 1 mmol/l (18 mg/100 ml). She responded rapidly to a 50 ml intravenous bolus of 50% dextrose. When parenteral feeding and dialysis are used simultaneously glucose passes across the semi-permeable membrane from the blood to the dialysate so that hypoglycaemia may occur. Insulin added to the parenteral fluid further decreases blood glucose concentrations. Stopping parenteral feeding 30-45 minutes before dialysis is started eliminates this danger of hypoglycaemia.

Adult↗
PubMed1982

Effects of systemic hyperthermia and intrahepatic infusion with 5-fluorouracil.

Potential hepatotoxicity from systemic hyperthermia (43 degrees C) +/- simultaneous hepatic artery infusion with 5-FU was evaluated in an animal model. Twenty-two dogs had aorta-vena caval shunts (8 mm Dacron grafts) placed, and 10 of these dogs had silastic catheters inserted in their hepatic arteries. Two weeks later, Group I (n = 8) was heated to 43 degrees C for one hour (distal esophageal + intrahepatic temperature) using the shunts and blood-heat exchangers; Group II (n = 6) was heated to 43 degrees C for one hour with simultaneous intrahepatic infusion of 5-FU (10 mg/kg); Group III (n = 8) was shamheated (37 degrees C) and underwent a one hour intrahepatic infusion with 5-FU (10 mg/kg). Serum alkaline phosphatase, SGOT, SPGT (IU/ml) and bilirubin were measured, and liver biopsies were obtained at 0 and 1 hour, at one and seven days. Mean SGOT levels increased significantly (P less than 0.05) in Group II from 19 +/- 2 to 31 +/- 6 and 63 +/- 18 at one hour and one day; these levels rose slightly in Group I from 31 +/- 5 to 40 +/- 8 and 47 +/- 8 at one hour and one day. Hepatocellular enzyme levels returned to normal at seven days in both groups. Mean SGOT and SGPT levels remained similar in Group III at all time periods. No significant differences in mean serum alkaline phosphatase or bilirubin levels were noted. There was no histologic evidence of hepatocellular necrosis at any time period. Survival was 6/8, 5/6 and 8/8 dogs in Groups I, II, and III, respectively. Systemic hyperthermia to 43 degrees C for one hour in dogs does not adversely affect serum hepatic enzymes or cell structure; reversible serum hepatic enzyme changes occurred when hyperthermia was combined with hepatic artery infusion with 5-FU.

Animals↗
PubMed1982

A method for culturing chick melanocytes: the effect of BRL-3A cell conditioning and related additives.

A method for growing chick embryo melanocytes is described that utilizes medium conditioned by Buffalo Rat liver (BRL-3A) cells. The dissected trunk region of each 72 h (Stages 14 to 19) embryo produces approximately 200,000 melanocytes (purity, 80%) when processed and cultured for 8 d. Thus, a typical experiment involving 20 embryos would produce a total of 4 x 10(6) melanocytes. Choice of serum, serum concentration, and cell density were determined experimentally. Partially purified multiplication stimulating activity (MSA) from BRL-3A cells and insulin were also tested as medium additives. MSA was not stimulatory, whereas insulin gave a positive response in 2% but not 10 or 0% serum. The final protocol used a modified F12 medium with 10% bovine calf serum conditioned by BRL-3A cells. Cultures were fed every other day. Small colonies of cells became evident by culture Day 3 and increased rapidly to Day 5 when pigmentation became obvious. Colony size continued to increase but more slowly from Days 5 to 8, whereas pigmentation increased rapidly and maximized on Day 8. There is a factor, or factors, present in BRL-3A conditioned medium that stimulates embryonic chick melanocytes to divide preferentially over contaminating cell types. This results in cultures that can provide adequate numbers and purity for biochemical studies.

Animals↗
PubMed1982

The metabolic effects of isotonic amino acid infusion in surgical sepsis.

28 normally nourished adult male and female patients who had undergone major elective surgery were maintained on dextrose-free isotonic amino acid solutions as their sole nutritional support. In the 6 days after surgery, 15 patients had no septic complications, 9 developed superficial sepsis, and 4 developed a deep seated collection of pus or deep sepsis. Patients without infection developed and maintained a fasting metabolic fuel profile within the first 3 days and increasingly spared protein. Superficial sepsis caused a small depression in serum ketone body concentrations but did not otherwise alter the fasting profile. Moreover nitrogen balances and plasma albumin and transferrin concentrations were unaltered by superficial sepsis which is not the response usually recognised with infection. Metabolic adaptation to the fasting state was lost in patients with deep sepsis and nitrogen losses were increased with greater decreases in plasma albumin and transferrin.

Journal Article↗
PubMed1982

An analysis of variations in the age structure of Fasciola hepatica populations in sheep.

The processes which govern the age structure of Fasciola hepatica populations in sheep were investigated by means of a simple mathematical model. The mortality of the metacercariae on the pasture was shown to be a factor of major importance. The mortality rate depends on the micro-climate that prevails at the pasture surface, and thus the age distribution curve of a population of flukes is also determined in part by the weather. This has important implications for the chemotherapy of fascioliasis: flukicides are not equally effective over the whole range of age-classes of parasite and so the factors which govern the age distribution curve of the parasite population within individual hosts ultimately determine the efficiency of chemotherapy.

Aging↗
PubMed1982

Pain relief after abdominal surgery--a comparison of i.m. morphine, sublingual buprenorphine and self-administered i.v. pethidine.

One hundred and twenty-six patients undergoing upper and lower abdominal surgery were studied after operation to compare the analgesic effects of i.m. morphine, sublingual buprenorphine and self-administered i.v. pethidine by Cardiff Palliator. There were no significant differences between analgesic regimens in respect of subjective linear analogue pain scores or static and dynamic lung volumes assessed at 24 and 48 h after operation and 5 days after operation in patients who underwent upper abdominal surgery. Sublingual buprenorphine produced more nausea and sedation than the other two treatments, but the differences were not clinically important. However, it offered considerable advantages in terms of ease of administration.

Administration, Oral↗
PubMed1982

Angular diameter of defocus blur discs.

When the eye is defocused for any reason, the diameter of the blur disc may be used as a first approximation to estimate effects on visual acuity. More exact treatment must use physical optics which take diffraction effects into account. Traditionally, defocus calculations of blur disc diameters have started with a particular schematic eye and rays traced to find the retinal image diameter of the blur disc. The angular or perceived diameter of this disc is then found by calculation of the angular subtense of the retinal blur disc measured at the back nodal point. A formula is presented here which bypasses the need for a specific schematic eye and is valid for any level of accommodation. The formula, although it is approximate, is very simple and only contains a defocus or refractive error quantity and the pupil diameter.

Methods↗
PubMed1982

Diurnal variations of corneal topography and thickness.

Measurements of central and peripheral corneal thickness, corneal topography, and central corneal curvature were made for 21 subjects at hourly intervals for 12 hr of 1 day for each subject. Values for corneal radius and asphericity were obtained from keratometry and photokeratoscopy, and their stability throughout the day was evaluated. Corneal radius was observed to steepen during the day, whereas asphericity remained constant. Corneal thickness was measured by pachometry and was found to be at its thickest on first awakening. Corneal curvature and central corneal thickness were highly correlated; low correlation was found between corneal asphericity and central corneal thickness. Some subjects exhibited large fluctuations in one or all of the parameters considered.

Adolescent↗
PubMed1982

Effects of thiopentone on the canine coronary circulation in acute experimental myocardial ischaemia.

Acute myocardial ischaemia was induced in five greyhounds by ligation of the anterior descending branch of the left main coronary artery. Changes in oxygen availability and consumption in the ischaemic area in response to thiopentone 10 mg kg-1 were compared with corresponding changes in non-ischaemic myocardium supplied by the circumflex artery. Despite a 40% reduction in arterial pressure, there were no significant changes in the oxygen availability/consumption ratio in either normal or ischaemic areas.

Acute Disease↗