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Biomedical subjects

J C Thompson

Publications and source records attributed to J C Thompson.

At least 397 records · Page 22Linked to original sources
PubMed1981

Factors which contribute to normalization in residential facilities for the mentally iii.

There is a growing body of evidence which suggests that normalization is significantly related to improved adaptive functioning among disabled persons. If this is so, then the concept of normalization should be taken into account in program planning. The present study suggests that characteristics of clients such as age and adaptive functioning level contribute to the achievement of high levels of environmental normalization in residential settings, but that characteristics of the residence, particularly its size, and the number of types of disability groups residing in the home, as well as the nature of the community in which the residence is located are even more important than individual characteristics. Some tentative conclusions for planning residential facilities are advanced.

Adult↗
PubMed1981

Predicting adaptive functioning among mentally ill persons in community settings.

Attempts to improve instrumental role performance among mentally ill persons have traditionally focused on the modification of individual level variables. Recent interest in environmental-behavioral linkages, however, has led to attempt to isolate environmental variables which are both readily manipulable and significantly related to improved instrumental role performance. The present study examines the impact of a variety of individual, residential, and community variables on instrumental role performance using multiple regression analysis. The 10 variables in the equation had a multiple r of .77 with total score on the Residential portion of the Adaptive Functioning Index, indicating that they account for 60% of the variance in scores. Individual level variables account for 3% of the variance, while environmental variables, primarily those related to normalization account for 57% of the variance. The data suggest that environmental normalization may be an effective technology as well as an ideology.

Adaptation, Psychological↗
PubMed1981

Does luminal gastrin stimulate gastric acid secretion?

The effects of pentagastrin on acid secretion, short circuit current, electrical conductance and potential difference were determined in isolated bullfrog fundic mucosa. Biologically active luminal pentagastrin had no effect on gastric mucosa, even at a concentration 100 times higher than that necessary for stimulation of the mucosa from the serosal side. It is concluded that luminal gastrin does not appear to have a physiologic role in gastric secretory processes.

Animals↗
PubMed1981

Colostral transfer of gamma glutamyl transpeptidase in calves.

Serum gamma glutamyl transpeptidase (GGT) levels in blood samples taken from normal calves which bad suckled colostrum were much higher than those found in healthy adult cattle. Levels of over 60 times the normal adult level were observed. These high levels of GGT took approximately 5 weeks to decline to adult values. Calves which appeared to have not received or absorbed colostrum had GGT levels which would be considered normal in adult cattle. A calf with serum gamma globulin levels which indicated an intermediate amount of colostrum absorption had a level of GGT which was intermediate between that expected for normal adult cattle and that found in calves which had more fully absorbed colostrum. The mean GGT level observed in colostrum from 6 newly-calved cows was over 800 times the mean serum GGT level of the same 6 cows. It therefore appears most likely that GGT is concurrently absorbed with colostrum by calves and this gives rise to the very high levels seen in normal calves. Calves with very high levels of serum GGT also had raised levels of alkaline phosphatase (AP) which slowly declined but never reached normal adult levels within the 53-day period of observation. It therefore appears that high levels of both GGT and AP are achieved by calves at the time of colostrum absorption and it is concluded that clinical interpretation of serum GGT and AP levels in young calves is closely dependent upon parallel knowledge of their serum gamma globulin levels.

Alkaline Phosphatase↗
PubMed1981

Release of cholecystokinin in man: correlation of blood levels with gallbladder contraction.

Although it is generally assumed that release of cholecystokinin (CCK) is the chief mechanism by which a fatty meal causes contraction of the gallbladder, measured release of CCK and gallbladder contraction have never been correlated. We have achieved this correlation in eight adult male volunteers, by means of a specific radioimmunoassay for CCK and by ultrasonographic imaging of the gallbladder. This study validates our CCK radioimmunoassay and correlates measured concentrations of CCK with changes in gallbladder size measured by ultrasonographic examination. Basal concentrations of CCK (82.6 +/- 10.4 pg/ml) rose significantly to a maximum of 411.1 +/- 79.9 pg/ml at 16 minutes after intraduodenal instillation of medium-chain triglyceride (Lipomul). Mean basal volume of the gallbladder was 34.6 cm3; maximum reduction of gallbladder volume (to one-third of original) was achieved at 18 minutes. Elevated CCK concentrations began to fall toward basal, and the gallbladder began to refill at 25 minutes. Results obtained after oral ingestion of Lipomul provide similar results. Linear regression analysis demonstrated excellent correlation between concentrations of CCK and gallbladder size during both contraction and relaxation phases. Future study of this correlation may be useful in patients with manifest dysfunction of the gallbladder, as well as in individuals known to be at risk of gallbladder disease.

Adult↗
PubMed1981

Radioimmunoassay study of hepatic clearance and disappearance half-time of somatostatin and vasoactive intestinal peptide in dogs.

The effects of hepatic transit on concentrations of synthetic cyclic (ovine) somatostatin and of highly purified (porcine) vasoactive intestinal peptide were studied in five conscious dogs prepared with indwelling portal catheters. The peptides were infused via peripheral vein catheters or the portal catheters for 40 minutes at actual integrated doses of 2.8 pmol/kg/min for vasoactive intestinal peptide an 8.2 pmol/kg/min for somatostatin. Specific radioimmunoassays were used for the measurement of the circulating peptides. As estimated from the plateau peptide concentrations achieved a hindleg vein during the portal and the peripheral infusions, the transhepatic loss of immunoreactive vasoactive intestinal peptide was 72.9 +/- 2.1%, against 27.5 +/- 12.5% for somatostatin. For the given doses of peptides infused systematically, the half-life, metabolic clearance rate, and distribution volume were, respectively, 1.80 +/- 0.1 minutes, 39.3 +/- 5.2 ml/kg/min, and 103.7 +/- 14.8 ml/kg for vasoactive intestinal peptide, and 1.0 +/- 0.2 minutes, 95.2 +/- 12.5 ml/kg/min, and 114.7 +/- 6.0 ml/kg for somatostatin. These results indicate that (ovine) somatostatin and (porcine) vasoactive intestinal peptide are both readily cleared from plasma in dogs. In the present experimental conditions, vasoactive intestinal peptide, but not somatostatin, was rapidly altered through hepatic transit so that it escaped recognition by the assay system.

Animals↗
PubMed1981

Hormone-stimulated release of pancreatic polypeptide before and after vagotomy in dogs.

Concentrations of pancreatic polypeptide (PP) in peripheral blood were measured before, during, and after infusions of graded doses of synthetic human gastrin I (SHG-I), cholecystokinin 99% pure (CCK-99%), CCK octapeptide (CCK-OP), and pure natural porcine secretin in six dogs with gastric and duodenal fistulas. Studies were repeated after truncal vagotomy. Significant increases in concentrations of PP were found with 1 microgram . kg-1 . h-1 of SHG-I, 0.25 and 1.0 microgram . kg-1 . h-1 of CCK-99%, and 0.06 and 0.25 micrograms . kg-1 . h-1 of CCK-OP. Significant increases persisted after vagotomy, except at the lower dose of CCK-OP. Postvagotomy responses were significantly less than prevagotomy, except at the higher doses of CCK-99% and CCK-OP. Pure secretin did not change concentrations of PP in blood before or after vagotomy. The most potent stimulant for PP release on a molar basis was CCI-99%, followed by CCK-OP and SHG-I. The results suggest that cholinergic and humoral agents of the gastrin-cholecystokinin family interact in the normal physiological response of PP to food and that, in dogs, CCK-like peptides are more potent than gastrin.

Animals↗
PubMed1981

Action of pancreatic polypeptide on exocrine pancreas and on release of cholecystokinin and secretin.

We have studied the effect of exogenous porcine pancreatic polypeptide (PP; 0.8 and 2.1 microgram/kg . h, iv) on endogenously stimulated pancreatic exocrine secretion in five pancreatic-fistula dogs. Plasma levels of cholecystokinin (CCK), secretin, and PP were measured in addition to pancreatic secretion of water, bicarbonate, and protein. Intraduodenal infusions of acid and a mixture of phenylalanine and tryptophan were used to stimulate hormone release. PP caused a dose-dependent inhibition of endogenously stimulated pancreatic secretion, whereas the release of CCK and secretin was not affected. Duodenal acidification and intraduodenal infusion of phenylalanine and tryptophan caused a significant release of PP. This study shows that: 1) PP suppresses pancreatic secretion by means of a mechanism that is probably direct; this effect is not mediated through inhibition of release of CCK or secretin, and 2) phenylalanine and tryptophan, both strong stimulants of CCK release, cause a substantial rise in PP in peripheral blood. The mechanism of PP release may involve CCK (in previous studies, we have shown a rise in circulating PP levels after iv CCK infusion).

Animals↗
PubMed1981

Response-surface-optimized, zinc-enhanced assay for serum alkaline phosphatase.

An optimized assay for alkaline phosphatase (EC 3.1.3.1) is reported. A discrete analyzer, the DuPont Automatic Clinical Analyzer (aca), was used for this study. The assay is based on results of response-surface experimental co-optimization techniques, and response is enhanced over the present aca assay. A key feature is the incorporation of zinc ions, both to fully optimize the assay and to reduce the sensitivity of measured activity to zinc-binding impurities in the buffer, 2-amino-2-methyl-1-propanol. In addition, a simple technique is described for measuring relative concentrations of zinc-binding impurities in this buffer. These features should be considered in the design of any assay for alkaline phosphatase that is based on p-nitrophenyl phosphate as substrate and 2-amino-2-methyl-1-propanol as buffer.

Alkaline Phosphatase↗
PubMed1980

Role of gastrin in vagally-stimulated pancreatic secretion.

In an attempt to clarify the contribution of antral gastrin to the vaginal stimulation of pancreatic secretion, we have measured the effect of total excision of the antral mucosa on pancreatic secretion induced by electrical vagal stimulation in eight anesthetized dogs. Stimulation was done before excision of the mucosa, and after excision, with and without a gastrin background. Mucosal excision reduced pancreatic volume response to 25% and pancreatic protein response to 32% of the respective responses obtained before excision; gastrin release in response to vagal stimulation was completely abolished. With a gastrin background (0.5 microgram/kg-hr of synthetic human gastrin-17-I), which resulted in serum gastrin concentrations higher than those obtained by vagal stimulation before excision of antral mucosa, the pancreatic volume and protein response showed only partial restoration. These studies provide evidence that vagal pancreatic secretion is only partially gastrin-dependent, and that other antral factors, probably vagally modulated intramural cholinergic pathways, are involved.

Animals↗
PubMed1980

Release of vasoactive intestinal peptide by distention of the proximal stomach in dogs.

The effect of transient proximal gastric distention was studied in six conscious dogs previously submitted to antrectomy and Billroth I anastomosis (and in which the intragastric pH was not altered), and in five anaesthetised dogs prepared with an innervated acute fundic pouch in which the pouch lumen was acidified with 0.15 M hydrochloric acid. Levels of vasoactive intestinal peptide (VIP) in portal and peripheral plasma were measured by radioimmunoassay. In conscious antrectomised dogs, distention of the proximal stomach to volumes of 250 and 500 ml evoked a significant rise of portal VIP concentration, with a maximal variation of 32.7 +/- 4.4 to 67.7 +/- 14.8 pg ml-1, which was hardly reflected in systemic blood. In the anaesthetised dogs, transient distention of the acute fundic pouch with 0.15 M hydrochloric acid under a pressure of 40 cm of water elicited a significant rise of portal VIP from 36.2 +/- 8.9 to 59.8 +/- 12.4 pg ml-1 (P < 0.05) without any significant variation of the peptide concentration in peripheral plasma. These results indicate that vasoactive intestinal peptide is released under transient proximal gastric distention in dogs, and that this response is not solely dependent upon the acid secretory effect of distention in this species.

Animals↗
PubMed1980

Effects of gastrin on circulating levels of somatostatin, pancreatic polypeptide, and vasoactive intestinal peptide in dogs.

The effect of synthetic human gastrin I, infused at two doses, on the concentrations of somatostatin, pancreatic polypeptide, and vasoactive intestinal peptide in portal and systemic blood was studied in six anesthetized dogs. Intragastric pH was maintained at 5.5, and acid output was measured by intragastric titration. Significant increases in somatostatin and pancreatic polypeptide concentrations in portal blood were found with the lower dose of gastrin (0.5 microgram/kg . h) infused for 40 min. When gastrin was infused at 1.5 microgram/kg . h for 100 min, both portal and systemic blood concentrations of somatostatin and pancreatic polypeptide rose significantly. Cimetidine (300 mg, as an iv bolus), given 40 min after the beginning of the second infusion, did not affect gastrin-stimulated release of somatostatin and pancreatic polypeptide, whereas acid output was completely abolished. Vasoactive intestinal peptide concentrations did not change with the infusion of either dose of gastrin. This daily shows that gastrin releases somatostatin and pancreatic polypeptide in a dose-dependent fashion, and since this release was not acid mediated, it appears likely to be a direct action of gastrin.

Animals↗
PubMed1980

Immunoreactive somatostatin and vasoactive intestinal peptide in the digestive tract of cats.

Somatostatin and vasoactive intestinal peptide were measured by radioimmunoassay in acetic acid extracts of tissue samples from the digestive tracts of seven adult cats. The concentration of immunoreactive somatostatin in antral mucosa (2926 +/- 978 pmol/g wet weight, mean +/- SE) was far above the concentrations in the head of the pancreas (442 +/- 94), distal duodenum (377 +/- 91), and ileum (355 +/- 48). Large amounts of immunoreactive vasoactive intestinal peptide were recovered from both mucosal and muscular layers of gastrointestinal tract; the highest values were observed in the muscular layer of the cecum (579 +/- 82 pmol/g) and the mucosa of the right colon (564 +/- 244). The mucosal/muscular layer ratio of vasoactive intestinal peptide concentrations increased caudally from 0.20 in the esophagus to over 1 in the ileum and colon. Upon gel filtration on G-50 Sephadex, somatostatin in the antrum, duodenum, and pancreas were eluted as a predominant peak in the volume of the tetradecapeptide, but somatostatin from the ileum and cecum was associated with a major faster component. Vasoactive intestinal peptide in the muscular layer of gastrointestinal tract and in mucosa of antrum and duodenum consisted essentially of a single form, which coeluted with the purified porcine peptide; a slower component was detected in the mucosa of the ileum and cecum. These reults indicate molecular heterogeneity of both immunoreactive somatostatin amd vasoactive intestinal peptide in the digestive tract of cats, and suggest that the variable ratio of the different molecular forms of each peptide along the gastrointestinal tract may reflect regional specificity of biologic effects and metabolism.

Animals↗
PubMed1980

Effects of test meal, intragastric nutrients, and intraduodenal bile on plasma concentrations of immunoreactive somatostatin and vasoactive intestinal peptide in dogs.

Specific radioimmunoassay were used to measure somatostatin and vasoactive peptide in portal and peripheral plasma from conscious dogs prepared with indwelling portal catheters. In six animals with intact stomachs, a test meal induced a significant rise of portal and peripheral somatostatin, while the significant response of vasoactive intestinal peptide in portal plasma was not reflected in peripheral blood. Similar somatostatin and vasoactive intestinal peptide responses were observed in six dogs previously submitted to antrectomy and Billroth I anastomosis, when given the same test meal, while the gastrin response was 20% of the response in the intact dogs (P < 0.01). The effects of intragastric instillation of 300 ml dextrose, casein hydrolysate, and Intralipid, adjusted to 300 mosmol/kg and pH 7.0, were studied in six dogs with intact stomachs. Casein and Intralipid induced significant increases of somatostatin in portal and peripheral plasma, while VIP increased after Intralipid only, both in portal and peripheral blood. Dextrose resulted in no significant variation of either peptide in portal or in systemic plasma. Intraduodenal infusion of isotonic bile induced a significant release of somatostatin, both in portal and peripheral plasma, but no significant vasoactive intestinal peptide response. These results indicate that several factors can evoke a significant release of somatostatin in dogs, and that the variations of the peptide concentration in portal plasma are reflected in peripheral blood. Among the factors tested, only intragastric fat evoked a vasoactive intestinal peptide response that could be measured in peripheral blood.

Animals↗