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Biomedical subjects

M Westphal

Publications and source records attributed to M Westphal.

At least 163 records · Page 9Linked to original sources
PubMed1984

Beta-endorphin: demonstration of binding sites in three human neuroblastoma cell lines specific for the COOH-terminal segment of the human hormone.

This communication reports for the first time specific binding sites in human neuroblastoma cells for human beta-endorphin (beta h-EP). Three cell lines (IMR-32, NMB and Kelly) were investigated and found to bind tritiated beta h-EP with an apparent dissociation constant of 2.2-4.2 nM. Further characterization with camel beta-EP and synthetic analogs indicated that the binding is most likely mediated by the COOH-terminal segments. beta h-EP-(6-31) had significant potency (15-75%) and beta h-EP-(1-27) was without displacing activity. The camel beta-EP has below 1% of the human beta-EP activity.

Binding, Competitive↗
PubMed1984

Detection of bovine pancreatic trypsin inhibitor (bPTI) in bovine and ovine pituitaries, bovine brain, and adrenal medulla. A specific radioimmunoassay for bPTI.

An antiserum against bovine pancreatic trypsin inhibitor (bPTI) has been raised in rabbits. The antiserum does not cross-react with known pituitary hormones and other proteins. A specific radioimmunoassay for bPTI has been developed. The ED50 is about 250 fmol per assay tube and the sensitivity is reliable to 15 fmol per tube. Immunoreactivity could be detected in bovine and sheep pituitaries, bovine brain, and adrenal medulla, but not in human, pig, and rat pituitaries. In the bovine pituitary the immunoreactivity is restricted to the posterior lobe.

Adrenal Medulla↗
PubMed1984

In vitro secretion of pro-opiomelanocortin (POMC) derived peptides in human ACTH-producing pituitary adenomas: evaluation of hormone ratios in different functional states.

In 14 cases of ACTH-producing pituitary adenomas (8 cases of Cushing's disease and 6 cases of Nelson's syndrome) dispersed cells prepared from adenoma tissue were incubated in a superfusion or static incubation system and investigated for ACTH, beta-endorphin (beta-EP) and beta-lipoprotein (beta-LPH) production. Effects of cortisol and lysine vasopressin (LVP) were evaluated. During the superfusion a qualitatively parallel secretory pattern is obtained for all hormones. Quantitatively, however, the response to LVP stimulation is more pronounced for beta-endorphin-like immunoreactivity (beta-LPH/beta-EP-IR) causing ACTH/beta-LPH/beta-EP-IR ratios to change throughout single experiments. beta-EP/beta-LPH ratios, however, which were estimated by means of Sephadex G-50 gel chromatography at various key points of the superfusion, were constant for each tumor, although variable between different adenomas, ranging from 0.68 to 2.0. The results suggest neither a differential control for the secretion of the peptides investigated within individual tumors nor a direct effect of cortisol or LVP on pro-opiomelanocortin processing. Summarizing clinical data and in vitro findings such as secretory behavior or hormone ratios, we can find no characteristic differences between Nelson's syndrome and Cushing's disease.

Adenoma↗
PubMed1984

beta-Endorphin: characterization of binding sites specific for the human hormone in human glioblastoma SF126 cells.

The established human glioblastoma cell line SF126 was found to bind tritiated human beta-endorphin (beta h-EP) in a saturable fashion. From displacement studies, the ED50 was estimated to be about 2.5 nM. The Kd was estimated as 1.9 X 10(-9) M and Scatchard analysis showed a biphasic pattern with a predominant low-affinity component. Binding reached a maximum at about 90 min at 22 degrees C and was instantaneously reversible. Tritiated [D-Ala2,D-Leu5]enkephalin and tritiated dihydromorphine did not bind to the cells. Sodium at a concentration of 150 mM decreased the specific binding by 80%. The interaction with the cellular binding site appeared to be mediated by the COOH-terminal segment of beta h-EP, as beta h-EP-(6-31) retained a high potency for displacing tritiated beta h-EP, and beta h-EP-(1-27) has no activity. Camel beta-EP was only about 1% as active as the human hormone.

Binding, Competitive↗
PubMed1984

Synthesis of human pancreatic growth hormone-releasing factor and two omission analogs by segment-coupling method in aqueous solution.

The human growth hormone-releasing factor (GRF) peptides [GlyS15]-GRF-(1-15) (IV), trifluoroacetyl-GRF-(20-44) (VI), trifluoroacetyl-GRF-(18-44) (VIII), and trifluoroacetyl-GRF-(16-44) (X) were synthesized by the solid-phase method. Each of the peptides was reacted with citraconic anhydride and the trifluoroacetyl group was removed by reaction with 10% hydrazine in water. The citraconylated GRF-(1-15) peptide was coupled to the (20-44), (18-44) or (16-44) peptides by reaction with silver nitrate/N-hydroxysuccinimide to give GRF-(1-15)-(20-44) (XII), GRF-(1-15)-(18-44) (XIII), or GRF-(1-44), respectively. GRF-(1-44) was shown to stimulate the release of rat growth hormone from rat pituitary cells with an ED50 = 8.8 X 10(-11)M. Peptides XII and XIII were inactive, either as agonists or as antagonists of the action of GRF-(1-44).

Animals↗
PubMed1984

Monoclonal antibody against cytoplasmic lectins of Dictyostelium discoideum: cross-reactivity with a membrane glycoprotein, contact site A, and with E. coli beta-galactosidase and lac repressor.

Monoclonal antibodies were raised against two soluble, galactose-binding lectins from cells of Dictyostelium discoideum, discoidin I and II. These antibodies reacted not only with both discoidins, but also with a plasma membrane glycoprotein of aggregation competent cells, called contact site A, and with two carbohydrate-binding proteins of E. coli, beta-galactosidase and lac repressor. The possibility that the antibody recognizes a structure common to different carbohydrate-binding proteins is discussed. The two carbohydrate-binding proteins of E. coli share with discoidin I the sequence -Ser-X-X-Ile-His(Pro)-Pro(His)-Leu-Thr- which might be responsible for the cross-reactivity.

Amino Acid Sequence↗
PubMed1984

Human beta-endorphin. Synthesis and biological activity of analogs with modifications in residue positions 3, 4 or 5.

Three analogs of human beta-endorphin (beta h-EP) have been synthesized by the solid-phase method: [Phe2, Gly4]-beta h-EP(I), [Tyr5]-beta h-EP (II), and [Trp5[-beta h-ET (III). Analogs I and II are related to the highly potent hybrid analog [dermorphin1-7]-beta c-EP (beta c-EP). Radio-receptor-binding and analgesic assays gave relative potencies as follows, respectively: beta h-FP, 100, 100; I, 51, 43; II, 64, 30; III, 15, 4. The high potency of [dermorphin 1-7]-beta c-EP is not due to any one of the following structural elements: D-Ala2, Phe3-Gly4, Tyr5, and Pro6. Increasing hydrophobicity in position 5 (Met in beta-EP) leads to decreasing biological activity.

Amino Acid Sequence↗
PubMed1984

Human beta-endorphin. Synthesis and biological activity of analogs with modification in residue positions 8, 27, and 9 or 11.

Three analogs of human beta-endorphin (beta h-ER) were synthesized by the solid-phase method: [Gln8,Trp27]-beta h-EP (I), [Gln8,Arg9,Trp27]-beta h-EP (II), and [Gln9,Arg11,Trp27]-beta h-EP (III). Radioreceptor binding assay with use of tritiated beta h-EP as primary ligand gave relative potencies as follows: beta h-EP, 100;I, 778;II, 467;III, 449. Relative potencies in an analgesic assay were: beta h-EP, 100;I, 114;II, 165;III, 83. The 8-11 segment of beta h-EP can tolerate a net increase in charge of +2 without diminishing analgesic potency. The substitution of Glu8 may be one of the more dependable means of designing beta-endorphin antagonists.

Amino Acid Sequence↗
PubMed1983

Peptide E: opiate receptor binding profile in the rat brain membrane assay. Comparison with beta-endorphin.

Beta-endorphin (beta-EP) and peptide E were compared in respect to their binding potency in the rat brain membrane by radioreceptor binding assay using tritiated human beta-EP, [D-Ala2,D-Leu5]-enkephalin (DADLE), dihydromorphine (DHM) and ethylketocyclazocine (EKC) as primary ligands. When the potency of beta h-EP was chosen to be 100%, peptide E was equipotent with beta-EP in displacing DHM (95%) and EKC (103%) less potent for competing with beta h-EP (60%) and least active (7%) for displacing DADLE. It may be concluded that peptide E binds preferentially with the opiate mu and kappa receptors in the rat brain membrane.

Animals↗
PubMed1983

Comparative studies on the structural organization of membrane-depleted nuclei and metaphase chromosomes.

Interphase membrane-depleted nuclei and metaphase chromosomes were prepared in parallel with a nonionic detergent lysis procedure at low ionic strength. By flow microfluorometry we showed for the first time that cell lysates contain all stages of the cell cycle in the same proportions as the starting cell population. Morphologically intact membrane-depleted nuclei and metaphase chromosomes were isolated as non-aggregated structures on sucrose gradients. When analysed in the electron microscope, membrane-depleted nuclei that had been treated with 2M NaCl appeared as residual structures containing the pore complex-lamina layer attached to a halo of DNA filaments. In contrast, no distinct high salt-resistant structure was found with metaphase chromosomes. They formed a highly fragile network which disintegrated easily into small complexes connected with DNA filaments. High salt-resistant DNA-protein complexes were purified by Metrizamide density gradient centrifugation. The main difference in the protein composition of interphase and metaphase residual complexes was the presence in interphase of a protein triplet in the 60-75 kilodalton molecular weight range and its absence in metaphase. This protein triplet most likely corresponds to the lamins A, B, and C of the nuclear lamina. The combined results suggest that the main difference in the structural organization of interphase nuclei and metaphase chromosomes is the presence or absence of the pore complex-lamina layer.

Animals↗
PubMed1983

Synthesis of adrenal peptide E and some of its biological activities.

A synthesis of peptide E, a highly potent, 25-amino acid adrenal opioid peptide containing both a [Met]enkephalin at the NH2-terminus and [Leu]enkephalin sequence at the COOH-terminus, originally isolated from bovine adrenal medulla [D. L. Kilpatrick, T. Taniguchi, B. N. Jones, A. S. Stern, J. E. Shively, J. Hullihan, S. Kimura, S. Stein, and S. Udenfriend (1981) Proc. Natl. Acad. Sci. USA 78, 3265-3268], is reported. The synthesis was accomplished by the solid-phase method employing the 4-(aminoacyloxymethyl)phenylacetamidomethyl(Pam)-copoly(styrene-1% divinylbenzene) resin. Two synthetic strategies (N-indole formyl protected vs unprotected tryptophan) were followed and results compared and evaluated. It was determined that peptide E prepared with protection of tryptophan (residues 13 and 14) was preferred and gave final product that was readily purified by HPLC. The biological activity of the synthetic material was found to be equivalent to the reported activity of the natural compound.

Amino Acid Sequence↗
PubMed1983

[Dynamic cerebral computed tomography. A contribution to the nosology of cerebral space-occupying processes?].

Dynamic cerebral studies were carried out in 21 patients with cerebral abnormalities. Thirteen had tumours and eight showed vascular abnormalities. In most cases the diagnosis was confirmed by histology, but occasionally by angiography or by computed tomography and the clinical course. Dynamic cerebral studies were performed, involving the production of concentration-time curves following bolus injection of ordinary contrast medium. The type of contrast enhancement gave a better indication of the nature of the lesion. The method can be used together with the more common type of investigations, such as plain scans and contrast scans. The small number of patients requires further studies with larger numbers; for this a multi-centric study would be suitable.

Adult↗
PubMed1982

Monoclonal antibodies against contact sites A of Dictyostelium discoideum: detection of modifications of the glycoprotein in tunicamycin-treated cells.

Tunicamycin acts on cell aggregation in Dictyostelium discoideum by changing cell movement and by inhibiting the EDTA-stable type of intercellular adhesion. Tunicamycin-treated cells show unco-ordinated pseudopodial activity such that pseudopods are simultaneously extended from all parts of the cell surface, and the cells are unable to move in straight paths. Concurrent with the inhibition of formation of EDTA-stable contacts, N-glycosylation of a glycoprotein specific for aggregation-competent cells is inhibited. This glycoprotein, previously called contact site A, has an apparent mol. wt. of 80 kilodaltons (kd). In membranes of tunicamycin-treated cells, two components are detected that react with certain monoclonal antibodies against contact sites A: one component of 66 kd, the other of 53 kd apparent mol. wt. Another group of monoclonal antibodies reacts only with the 80-kd glycoprotein and the 66-kd component. These results are in accord with the assumption that the glycoprotein carries two carbohydrate chains, and that the antibodies differ in their requirement for glycosylation of the antigen. Despite the coincidence between blockage of EDTA-stable cell adhesion and inhibited glycosylation of contact sites A, direct involvement of the carbohydrate moieties of this glycoprotein in intercellular adhesion seems questionable. EDTA-stable cell adhesion has not been blocked by Fab fragments from antibodies that specifically react with the glycosylated protein.

Journal Article↗
PubMed1982

In-vitro secretion of ACTH in Nelson's syndrome.

Cell suspensions of ACTH cell adenomas of 10 patients with Nelson's syndrome were investigated for in-vitro secretion of ACTH. Two incubation systems, one using incubation beakers and the other a superfusion system, were employed. The cells were tested for their reactivity to lysine-vasopressin (LVP), cortisol, and combinations of both. LVP regularly provoked a rapid significant increase of ACTH secretion. The effect of cortisol was heterogeneous. Paradoxical initial stimulatory effects of cortisol were observed. There was a suppressive effect in some patients, which correlates to low proliferative activity in histological evaluation. In both systems a low secretory activity coincided with high proliferative activity in vivo.

Adrenocorticotropic Hormone↗
PubMed1982

Maternal risk factors in infants with very low birth weight.

To determine whether maternal risk factors associated with the delivery of very low birth weight infants under 1501 g are different from those associated with low birth weight infants of 1501 to 2500 g, prenatal data on 12,247 deliveries were evaluated. The sample contained 302 very low birth weight infants. Maternal race, age, height, weight, gravidity, parity, past pregnancy performance, and pregnancy complications were analyzed. Factors related to very low birth weight but not to low birth weight infants were previous abortions, previous fetal deaths, and hypertensive vascular disease. Race, maternal height, and prepregnancy weight were not related to very low birth weight but were associated with an increase in low birth weight. There was no significant difference in the rate of very low birth weight or low birth weight by maternal age from 14 to 40 years. These results contradict the concept of a uniform set of predisposing factors for birth of all infants weighing 2500 g or less.

Abortion, Spontaneous↗
PubMed1980

In vitro secretion of ACTH, beta-endorphin and beta-lipotropin in Cushing's disease and Nelson's syndrome.

Tissue from histologically confirmed ACTH cell adenomas in Cushing's disease (CD) and Nelson's syndrome (NS) was gained by transsphenoidal surgery. Combined enzymatic and mechanic agitation of tumor tissue yielded a cell suspension. Aliquots of the cell suspension were transferred to superfusion chambers immediately after isolation and investigated for ACTH and beta-endorphin production. Feedback action of cortisol (CO) and dexamethasone on basal hormone production and on lysine vasopressin (LVP) induced ACTH secretion were studied. Adenomatous tissue and anterior lobe tissue from the same patient in CD could be investigated simultaneously in 4 cases. The paraadenomatous tissue showed depression of basal and LVP-induced ACTH secretion. In all adenomatous tissues investigated there was missing or reduced suppression of basal ACTH secretion by physiological levels of CO. CO not only failed to suppress LVP-induced ACTH secretion but also seemed to enhance LVP stimulation in some experiments. This study confirms former results, that a missing or inversed feedback action or glucocorticoids in adenoma cells is a mechanism involved in the pathological ACTH secretion in CD and NS. Bioassayable and immunoreactive ACTH from media of superfusion and short-term static incubation were compared with beta-endorphin and beta-LPH in an assay detecting these two peptides with equimolar sensitivity. Secretory patterns were basically parallel but great differences showed in quantities of hormones secreted. In addition, Sephadex G-50 gel chromatography was performed to separate beta-endorphin from beta-LPH and to calculate the ratios. These profiles show great variations between different adenomas.

Adenoma↗
PubMed1979

Changes in average length of stay and average charges generated following institution of PSRO review.

A five-year review of accounting data at a university hospital shows that immediately following institution of concurrent PSRO admission and length of stay review of Medicare-Medicaid patients, there was a significant decrease in length of stay and a fall in average charges generated per patient against the inflationary trend. Similar changes did not occur for the non-Medicare-Medicaid patients who were not reviewed. The observed changes occurred even though the review procedure rarely resulted in the denial of services to patients, suggesting an indirect effect of review.

Accounting↗