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Biomedical subjects

T Schwartz

Publications and source records attributed to T Schwartz.

71 records · Page 4Linked to original sources
PubMed1980

Gastroenteropancreatic hormonal changes during exercise.

Peripheral plasma concentrations of gastroenteropancreatic peptides were measured during a 3-h period of bicycle exercise at 40% of maximal oxygen uptake in six normal men. Marked increases (P < 0.02) were found in vasoactive intestinal polypeptide (VIP) [1.8 +/- 0.7 (rest) vs. 22.3 +/- 5.4 pmol x l-1 (mean +/- SE) (3 h)], secretin (0.5 +/- 0.5 vs. 11.1 +/- 2.7 pmol x l-1), pancreatic polypeptide (PP) (4.0 +/- 1.5 vs. 46.3 +/- 11.5 pmol x l-1), somatostatin (SRIF) (12.8 +/- 1.2 vs. 17.7 +/- 0.6 pmol x l-1), whereas no changes occurred in gastric inhibitory polypeptide (37.3 +/- 5.9 vs. 39.2 +/- 9.8 pmol x l-1). Immunoreactive insulin and C-peptide decreased from 0.08 +/- 0.004 and 0.39 +/- 0.03 pmol x l-1, respectively, to 0.04 +/- 0.003 (P < 0.005) and 0.13 +/- 0.02 (P < 0.001). The significant decrease in C-peptide and in the C-peptide-to-insulin molar ratio indicate decreased insulin secretion and clearance, respectively, during exercise. Plasma glucose decreased [5.0 +/- 0.1 (rest) vs. 4.2 +/- 0.3 mmol.l-1 (3 h)] (P < 0.01). During 3 h of rest, none of the measured parameters had changed. The marked exercise-induced changes in plasma concentrations of PP, secretin, VIP, and SRIF are provocative. We know in detail neither the stimuli for the release of these peptides nor their physiological role during exercise.

Adolescent↗
PubMed1976

The heterogeneity of gastrin, with reference to conversion of gastrin-17.

High-resolution gel chromatography monitored by a sensitive radioimmunoassay for gastrin has disclosed that gastrin circulates in twenty different components. Since the assay is specific for the biological active sequence of gastrin (-Trp-Met-Asp-PheNH2), we conclude that all the twenty circulating molecular forms of gastrin encountered in this study may participate in the regulation of gastric acid secretion. There are two dominating forms of gastrin in serum: gastrin-34-like components and gastrin-17-like components. The former constituted 60% and the latter constitutes approximately 30% of the immunoreactive gastrins. We suggest that extragastrointestinal conversion of gastrin-17, released from tissue, is an important source of gastric-34-like components. Such conversion has been observed in intact man and pig. Studies with the isolated perfused porcine liver indicate that the liver is important in the metabolism of gastrin-17, and that conversion may be a hepatic function.

Animals↗
PubMed1976

Occurrence of human pancreatic polypeptide in pancreatic endocrine tumors. Possible implication in the watery diarrhea syndrome.

Eighteen endocrine pancreatic tumors were examined for the occurrence of cells producing insulin, glucagon, gastrin, human pancreatic polypeptide (HPP), and vasoactive intestinal polypeptide (VIP) and for A1 cells. More than half of the tumors were mixed, i.e., they contained more than one type of hormone-producing cell. The clinical symptoms were attributable only to one of the hormones produced by the mixed tumors. Three of four tumors causing the watery diarrhea syndrome contained both VIP and HPP cells. In one such tumor there was a strong predominance of HPP cells; the serum HPP levels of this patient were a thousandfold elevated, whereas her VIP levels were within the normal range. Several lines of evidence point to HPP as a possible agent causing the watery diarrhea syndrome. In many of our patients, HPP cells hyperplasia was present in the extratumoral pancreas. Such hyperplasia may give rise to the raised serum HPP levels seen in many patients having endocrine pancreatic tumors.

Diarrhea↗
PubMedDate not supplied

Unilateral superior rectus recession for the treatment of dissociated vertical deviation.

The management of dissociated vertical deviation (DVD) is an unsettled issue. Several authors have advocated bilateral superior rectus recession for all patients with DVD unless a dense amblyopia is present in the nonfixating eye. Our experience suggested that DVD was being successfully treated with unilateral bilateral superior rectus recession. We reviewed the charts of 57 patients who underwent graded unilateral superior rectus recession and 10 patients who had bilateral superior rectus recession for the treatment of DVD. DVD, a manifest deviation, was considered as distinct from occlusion hyperphoria, a latent deviation present only under cover. Of the patients who underwent unilateral superior rectus recession, only six developed a significant (14 prism diopters or more) DVD in the unoperated eye. The presence of any DVD in the unoperated eye appeared to be predictive of an unacceptable postoperative deviation (15 times greater chance, P less than .001). Patients with an occlusion hyperphoria in the unoperated eye showed no increased propensity to develop a significant DVD following surgery. The results of bilateral surgery were disappointing. Eight of ten patients had residual DVD in one or both eyes of 10 delta or greater. Our results suggest that unilateral surgery is an effective treatment of DVD in patients with a manifest deviation in only one eye. Although neither unilateral nor bilateral surgery was entirely satisfactory for the treatment of bilateral DVD, we recommend bilateral superior rectus recession for these patients.

Adolescent↗
PubMedDate not supplied

Presence of suicidality as a prognostic indicator.

BACKGROUND: Suicidal symptoms in depression are often thought to predict a higher severity of illness and a worse prognosis. AIMS: To determine if suicidal ideation at the time of treatment for major depression can predict response to antidepressant medication in primary care. SETTINGS AND DESIGN: A retrospective analysis of subjects receiving anti-depressant drugs in a primary care setting METHODS AND MATERIAL: Nine depressed patients (14%) who acknowledged suicidality on the PHQ-9 depression scale were followed up for and compared to a group of 54 (86%) depressed patients (controls) who did not have suicidal thoughts for four months. All were given treatment with antidepressants and followed with a disease management protocol where the PHQ-9 was used as a systematic outcome measure. STATISTICAL ANALYSIS: Descriptive measures and t-tests were utilized to show statistical significance. RESULTS: There were no statistical differences in remission from depressive symptoms based on the PHQ-9 scale after antidepressant treatment, between patients with suicidal thoughts (56%) and those without (44%). CONCLUSION: The presence of suicidality as a depressive symptom did not predict poorer clinical outcome when treating depression in the primary care setting in the patients studied.

Antidepressive Agents↗