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Biomedical subjects

S L Grainger

Publications and source records attributed to S L Grainger.

At least 19 recordsLinked to original sources
PubMed1994

Prevalence of dyspepsia: the epidemiology of overlapping symptoms.

Studies of the epidemiology of dyspepsia have been complicated by the use of different symptom definitions, subject populations and time frames of investigation. Published figures for the prevalence of dyspepsia vary from 20% to 40%, of which perhaps only a quarter can be attributed to peptic ulcer disease. General practitioners see only a fraction of the dyspepsia within the community, the majority of which is either ignored or treated by self-medication. However, dyspepsia still accounts for about 3-4% of all general practice consultations and for about 14% of all patients attending. In about half of all cases, even extensive investigation reveals no underlying organic lesion. There has been much recent interest in the clinical value of grouping dyspeptic symptoms into particular subtypes. These have been called ulcer-like, dysmotility-like and reflux-like. Although these patterns have descriptive value, there is no evidence that they result from discrete pathophysiological processes. Indeed, studies both in general practice and in the community show a large degree of overlap between them.

Dyspepsia↗
PubMed1991

Effects of anesthetic agents and abdominal surgery on liver blood flow.

The cause of postoperative liver dysfunction is often unclear, but a decrease in liver blood flow during anesthesia and/or major surgery may be important. Plasma half-life and clearance of indocyanine green were therefore measured in 42 patients before, during and after anesthesia and abdominal surgery. In 13 patients, liver blood flow was also estimated from indocyanine green extraction using hepatic vein catheterization. The major finding was an early decrease in estimated liver blood flow after induction of anesthesia, but not later during or after surgery. Mean indocyanine green half-life increased by 26% (p less than 0.005), mean indocyanine green plasma clearance decreased by 19% (p less than 0.01) and mean estimated hepatic blood flow decreased by 36% (p less than 0.005) during the first 30 min of anesthesia. These changes were greater in males and in patients older than 55 yr, but changes were similar with each of three anesthetic groups. Half-life, but not indocyanine green clearance, was also significantly prolonged by mid-operation in the older (greater than 55 yr) patients and in those undergoing lower abdominal surgery. We suggest that this period of reduced liver blood flow during anesthesia is caused by the effects of neuromuscular blocking agents and may contribute to postoperative liver damage.

Abdomen↗
PubMed1989

Reduced hepatic blood flow and intestinal malabsorption in severe falciparum malaria.

We have studied intestinal function and liver blood flow in Thai adults with complicated and uncomplicated falciparum malaria. The absorption of 3 orally administered test sugars, D-xylose, 3-O-methyl-D-glucose, and L-rhamnose, was greatly reduced in complicated malaria, while the lactulose/rhamnose absorption ratio was significantly increased. Hepatic blood flow was concomitantly reduced in severe malaria. These deviations reverted to normal in convalescence. Neither sugar absorption nor liver blood flow was reduced in uncomplicated falciparum malaria.

Adolescent↗
PubMed1989

Phosphomonoesterase activity of the cyanobacterium (blue-green alga) Calothrix parietina.

Cellular and extracellular phosphomonoesterase activities were compared in Calothrix parietina D550, a strain whose original environment has been studied in detail. Activity in both fractions became detectable at about the same stage in batch culture. Differences in the influence of environmental factors between the two were slight, suggesting a common origin. The optimum temperatures for cellular and extracellular activities were 40 degrees C and 30 degrees C, respectively, and the upper limits for detectable activity were 80 degrees C and 65 degrees C. The pH optimum for both cellular and extracellular activity was 10.0-10.2. When P-limited cultures were tested with p-nitrophenyl phosphate (pNPP) as substrate, Km values for cellular and extracellular activities were 43 and 33 microM pNPP, respectively. Eleven ions were tested for their influence on activity. In most cases the effect was low or negligible at concentrations likely to be present in nature or freshwater laboratory media. Where obvious effects occurred, these were usually apparent at lower concentrations with extracellular than cellular activity. One mM Ca led to a 40% increase in extracellular activity in comparison with 0.1 mM Ca, but had no effect on cellular activity. However, inorganic phosphate, which had a marked inhibitory effect at concentrations above 10 microM, brought about a similar response with cellular and extracellular activities (approximately 60% decrease with 100 microM).

Calcium↗
PubMed1988

Effects of cimetidine and ranitidine on plasma high-density lipoprotein subclasses in humans.

The effects of cimetidine (400 mg b.d.) and ranitidine (150 mg b.d.) on high-density lipoprotein (HDL) subclasses and other plasma lipoproteins were studied in 18 men and 15 women with reflux oesophagitis and/or duodenitis. Serum testosterone and sex hormone binding globulin (SHBG) concentrations were also measured. Treatment with either drug was continued for 12 weeks. Ranitidine had no significant effect on any measured variable in either men or women. Cimetidine had no effect in men, but in women it raised the cholesterol concentration in the HDL2 subclass by 15% after 8 weeks, and by 48% after 12 weeks. In females, cimetidine also reduced the concentrations of SHBG (by 24% at 12 weeks) and of total testosterone (by 25% at 12 weeks). The significance of these latter changes is uncertain, however, as estimates of the biologically active free testosterone concentration were unchanged.

Adult↗
PubMed1987

Teeth and benign oesophageal stricture.

In patients undergoing upper gastrointestinal endoscopy, benign oesophageal strictures were significantly more frequent (p less than 0.01) in those with severe tooth loss than in controls of the same age. This may be because of edentulous patients eating less solid and more liquid food, which would otherwise dilate the lower oesophagus, or poor salivary flow leading to both tooth loss and impaired neutralisation of refluxed gastric acid, or malnutrition. No association was found, however, between either oesophagitis or hiatus hernia and dentition.

Adult↗
PubMed1986

Three times daily or 8-hourly.

The timing of drug ingestion over 24 hours was assessed in 58 outpatients taking drugs three times daily. The mean time between 1st and 2nd dose was 5.7 hours, 2nd and 3rd 6.1 hours and between 3rd and 1st of the next day 12.2 hours. Based on a simulation of hydralazine pharmacokinetics, such irregular administration would increase peak levels by 10% and decrease trough levels by 64% compared with regular 8-hourly doses.

Adult↗
PubMed1985

A multiple dose pharmacokinetic and pharmacodynamic evaluation of conventional and 19/285 Oros formulations of metoprolol in healthy volunteers.

Plasma metoprolol concentrations and haemodynamic effects have been measured in six healthy male volunteers during once daily dosing with a 19/285 Oros system and twice daily dosing with 100 mg conventional tablets, on two separate occasions. Plasma drug concentrations throughout the day varied less with the Oros than with the conventional tablet regimen. Predosing concentrations were also higher with Oros but areas under the curve, after correcting for the differences in dose, were similar for the two preparations. Inhibition of exercise tachycardia was drug concentration dependent and was smoothly controlled through the day only with the Oros preparation. Predosing effects at steady-state were also greater for the Oros regimen. The decline in mean blood pressure, however, showed the same daily pattern for both regimens, and no significant differences were detected between Oros and conventional tablet treatments. The smoothness of the plasma profiles after Oros confirmed the controlled-release performance of the system in vivo and indicates its potential in the treatment of angina, cardiac arrhythmias and wherever it is important not to jeopardize steady selective beta-adrenoceptor blockade.

Adult↗
PubMed1983

Oral iron and the bioavailability of zinc.

The oral bioavailability of zinc was studied in nonpregnant adults before and 24 hours after two weeks of oral supplementation with iron and folic acid. Bioavailability was greatly reduced, and the shape of the plasma curves suggested that this was due to impairment of the intestinal absorption of zinc. The findings suggest that the reduced bioavailability of zinc occurs because of interelement competition in the bowel wall. This might induce zinc depletion.

Biological Availability↗
PubMed1983

Clearance and non-invasive determination of the hepatic extraction of indocyanine green in baboons and man.

1. The disposition of an intravenous bolus of indocyanine green (ICG) has been studied in healthy man and baboons using a novel analysis of a two compartment pharmacokinetic model. 2. This analysis enabled the hepatic extraction ratio (ER) of dye to be determined solely from the plasma disappearance curve, and the ER determined did not differ from that measured by hepatic vein catheterization. 3. When compared with clearance measured at steady state, the two compartment model gave a significantly more accurate determination of plasma clearance than did the conventional one compartment model. 4. It is concluded that, in health, liver blood flow may be calculated accurately and non-invasively after a single intravenous injection of ICG.

Adult↗
PubMed1983

Dose-response relationships of intravenous hyoscine butylbromide and atropine sulphate on heart rate in healthy volunteers.

Heart-rate responses to intravenous hyoscine butylbromide, atropine and physiological saline in cumulative dosage regimens have been recorded in six healthy subjects. Atropine sulphate induced bradycardia at low, and tachycardia at higher, dose levels whereas hyoscine butylbromide caused only tachycardia but with a flatter dose-response relationship. Exact potency ratios could not be calculated because of the differing dose-response curves. However, an approximate estimate from a comparison of equiactive doses at the upper part of the curve yielded a value less than one half that obtained from the drugs' affinity constants in guinea-pig ileum. The findings suggest that, in addition to its action as a muscarinic antagonist, hyoscine butylbromide is a ganglion blocker in man as it is in animals.

Adult↗
PubMed1982

Relation of simple clotting tests to clotting factor levels in liver disease.

The prothrombin time with Manchester and ox thromboplastins, the 'P & P' test of Owren and Aas, the partial thromboplastin time, the thrombin time and assays for factors II, V, VII, VIII:C, IX and X were performed by one observer in 18 patients with liver disease and 27 normal subjects; the prothrombin time and partial thromboplastin time were also carried out on another 28 similar patients by various observers. Routine liver function tests were measured in all patients. The prothrombin time with Manchester thromboplastin was well correlated with other clotting tests, and performing the other tests did not add to the information. Discriminant function analysis confirmed that clotting tests did not distinguish between different types of liver disease. Correlations between clotting tests and liver function tests reflected liver cell damage but were also influenced by acute phase reactions.

Adolescent↗