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Biomedical subjects

D J Sanders

Publications and source records attributed to D J Sanders.

68 records · Page 4Linked to original sources
PubMed1975

Does histamine have two vasodilator actions on the gastric mucosa?

It has been shown previously that there is a greater gastric mucosal blood flow response to histamine than to gastrin stimulation for similar acid secretory values. We have confirmed these observations under steady state conditions and also shown that the oxygen consumption depends on acid secretion in a similar way for both histamine and gastrin stimulation. Furthermore the degree of oxygen extraction from the gastric circulation is significantly less (p less than 0.001) during histamine stimulation than during gastrin stimulation. This supports the hypothesis that histamine causes a vasodilatation in the gastric mucosa in two ways, one may be linked to secretory activity and the other a pure dilator action.

Animals↗
PubMed1975

The mechanism whereby growth hormone-release inhibiting hormone (somatostatin) inhibits food stimulated gastric acid secretion in the cat.

Growth hormone-release inhibiting hormone (somatostatin) inhibits the gastric acid response to food in concious cats. We have confirmed that this tetradecapeptide blocks the food stimulated gastrin release. However, the inhibition of gastrin release is delayed relative to that of acid secretion, &howing that the inhibition of food stimulated acid secretion is by primary effect on the acid secretory mechanism. No evidence was found of potentiation of either the gastric acid output or serum concentration of gastric in response to food.

Animals↗
PubMed1975

Variation in the proportions of individual pepsins secreted by the cat in response to vagal stimulation and hypoglycaemia.

1. Gastric juice was collected at regular intervals during electrical stimulation of the vagus in anaesthetized cats and during insulin hypoglycaemia in both anaesthetized and conscious cats. The total amounts of acid and pepsin secreted were similar in the three groups. 2. Pepsins were examined by agar-gel electrophoresis. Resting juice contained two pepsins, and up to nine pepsins could be detected after stimulation. Three patterns of pepsin secretion were found. 3. The most noticeable feature was the variation in the proportion of total pepsin attributable to the pepsin which migrated most rapidly during electrophoresis (pepsin 1). In response to insulin hypoglycaemia, anaesthetized cats secreted only a small proportion of total pepsin 1 and conscious cats secreted a large proportion as pepsin 1. During direct electrical stimulation of the vagus, the proportion of pepsin 1 rose. 4. The possibility of a dependence of pepsin 1 secretion on vagal stimulation is discussed and the relevance of this to peptic ulcer and to vagotomy is considered.

Animals↗
PubMed1975

The effect of sympathetic nerve stimulation on acid secretion, regional blood flows and oxygen usage by stomachs of anaesthetized cats.

1. Gastric acid secretion, and total gastric and mucosal blood flows (amidopyrine technique) were measured in anaesthetized cats. Oxygen contents of arterial and gastric venous blood were measured using an oximeter. 2. Splanchnic nerve stimulation (10 Hz) significantly reduced the acid output and total gastric and mucosal blood flows produced in response to maximal gastrin pentapeptide infusions. 3. The arterial haemoglobin concentration was significantly reduced during splanchnic nerve stimulation, and this is consistent with the hypothesis that the splanchnic nerve effect is directed against precapillary sphincters. 4. During the period of inhibition, gastric oxygen consumption and acid secretion were reduced to similar degrees. There was no significant change in oxygen extraction by the stomach. 5. It remains possible that the splanchnic nerves directly inhibit the parietal cell activity.

Animals↗
PubMed1975

The effect of sympathetic nerve stimulation on serum gastrin, gastric acid secretion and mucosal blood flow responses to meat extract stimulation in anaesthetized cats.

Chloralose anaesthetized cats were prepared with fundic and antral pouches. Fundic mucosal blood flow was measured by the amidopyrine technique and serum gastrin was measured by radioimmunoassay. 2. Meat extract suspension in the pyloric antrum produced a highly significant sixfold increase in arterial serum gastrin concentration (P less than 0-001). 3. The mean ratio of the fundic mucosal blood flow to acid secretory responses (deltaMBF/deltaH+ ratio) of 0-142 +/- 0-026 (25) ml./muequiv H+, is very similar to the values previously published for exogenous gastrin stimulation. 4. Splanchnic nerve stimulation, during responses to meat extract stimulation, produced significant reductions in gastric acid secretion (P less than 0-025), fundic mucosal blood flow (P less than 0-02), Arterial serum gastrin concentration (P less than 0-01) And gastrin delivered to the mucosa (P less than 0-001). 5. In the 30 min period following the end of splanchnic nerve stimulation only arterial serum gastrin concentration remained significantly reduced.

Animals↗
PubMed1975

Gastrin response to meals of different composition in normal subjects.

The serum gastrin responses and the integrated gastrin responses to eating three meals of very different composition were studied in the same normal subjects on different days. Two meals, a milk meal of 500 ml, and a breakfast of eggs, toast, butter, marmalade, fruit juice and coffee, were eaten at breakfast time. The serum gastrin responses to these meals were compared and contrasted with the concentrations observed when the subjects fasted over the same time of day. A steak meal was eaten at lunch time. There were no significant differences between the mean serum gastrin concentrations to the three meals but each meal produced a significant increase in serum gastrin above fasting levels. When the prefeeding gastrin concentration was subtracted from the gastrin responses then the integrated responses to the steak meal were greater than those to either of the breakfast meals. Considerable variability in response to any one meal was observed within the group of subjects, but those subjects who produced high serum gastrin concentrations to one meal did so to the others. Conversely, at low response to one meal was reflected in low responses to the other two meals. Fasting serum gastrin concentration was correlated with the age of the subject. Repeatability of the response to one meal was tested in two subjects who ate the same meal on four separate occasions showing their responses to be repeatable.

Adult↗
PubMed1971

The effect of splanchnic nerve stimulation on gastric acid secretion and mucosal blood flow in the anaesthetized cat.

1. Electrical stimulation of the vagus nerves produced a parallel increase in gastric acid secretion and gastric mucosal blood flow.2. Gastric acid secretion and mucosal blood flow, stimulated by pentapeptide infusions or by vagal stimulation, were markedly and equally reduced by electrical stimulation of splanchnic nerve fibres.3. The splanchnic stimulated reduction in acid and mucosal blood flow occurred only when the rise in blood pressure, normally associated with splanchnic stimulation, was prevented by inclusion of a pressure reservoir in the circulation.4. There was evidence that the effect of the splanchnic nerves was not mediated by release of adrenaline from the adrenal medulla.

Adrenal Medulla↗
PubMed1971

Pepsin secretion, gastric motility and mucosal blood flow in the anaesthetized cat.

1. There is a weak relationship between pepsin output and gastric mucosal blood flow (MBF) during vagal stimulation. When compared with the strong relationship between H(+) output and MBF, this suggests little dependence of pepsin secretion on MBF.2. Gastric MBF per unit H(+) output was significantly greater during vagal stimulation, when H(+) secretion was accompanied by pepsin secretion, than during pentapeptide stimulation when no pepsin was secreted.3. Pepsin output was not reduced during splanchnic stimulation whereas MBF and acid output were, when blood pressure was kept constant.4. Splanchnic stimulation did not produce any pepsin secretion.5. Gastric motor responses to vagal stimulation and to I.A. injections of acetylcholine were equally reduced by splanchnic stimulation.

Acetylcholine↗
PubMed1971

Splanchnic nerve inhibition of gastric acid secretion and mucosal blood flow in anaesthetized cats.

1. Efferent electrical splanchnic nerve stimulation will significantly inhibit gastric acid secretion and mucosal blood flow (MBF) stimulated by either large I.V. doses of pentapeptide or histamine, if the rise in blood pressure is prevented.2. Splanchnic stimulation will also reduce the increase in MBF in response to infusions of isopropylnoradrenaline, if the blood pressure rise is prevented.3. Evidence is presented which suggests that the splanchnic nerve inhibitory effect is not due to reducing the amount of stimulant arriving at the gastric mucosa.4. By analysing the responses to histamine, when acid secretion is accompanied by a large MBF relative to the pentapeptide responses, it is suggested that the inhibitory effect of splanchnic nerve stimulation is due to vasoconstriction.5. It remains possible that there is a direct inhibitory effect on the parietal cells.

Animals↗
PubMedDate not supplied

Maximum grip strength in normal subjects from 20 to 64 years of age.

The purposes of this study were to develop normative maximum grip strength (GRIP) data for men and women aged 20 to 64 years, separated into nine five-year age groups, and to develop prediction equations for GRIP using gender, age, height, weight, and hand dominance. A total of 1,182 volunteers (553 men and 629 women) participated in the study. Maximum hand grips were obtained using the Jamar dynamometer with standardized positioning and instructions. The hand to be tested first was chosen randomly. Each hand was then tested alternately. Three trials were performed on each hand. The highest GRIP for each hand was used for analysis. Two-way analyses of variance showed significant differences between the right and left hands and across the age groups for both genders. Follow-up analyses showed that significant decreases occurred between the age groups of 50-54 and 55-59 years in men and between the age groups of 50-54 and 60-64 years in women. The data also indicated that right and left GRIPs were highly correlated with each other (r = 0.93). Gender, height, and weight moderately correlated with both GRIPS (r = 0.52-0.73. Age correlated weakly with both GRIPs (r = -0.17). If either the right or the left GRIP was known, the other GRIP could be predicted easily from the known GRIP, with 87% of variance accounted for. Without the knowledge of the other GRIP, either GRIP could be predicted through gender, height, weight, age, and hand dominance, with 61% to 62% of the explained variance. The norms and prediction equations of GRIP developed in this study for men and women aged 20 to 64 years will help clinicians with decision making regarding grip strength.

Adult↗