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Biomedical subjects

R C Allen

Publications and source records attributed to R C Allen.

At least 145 records · Page 8Linked to original sources
PubMed1980

Benzenesulfenamides as antihypertensive agents. Substituted piperidine and 1-arylpiperazine derivatives.

The synthesis and antihypertensive activity of several piperidinebenzenesulfenamides related to the previously reported potent hypotensive agents 1 and a series of 1-arypiperazine-4-benzenesulfenamides 7 are described. A number of the latter compounds exhibit marked antihypertensive properties. The most interesting of these compounds, 7a and 7k, have been evaluated in several other animal models. In addition, benzenesulfinamides 9a and 9b and benzensulfonamides 10a and 10b have been prepared for comparison purposes.

Animals↗
PubMed1980

Comparisons of alveolar and peritoneal macrophages: soluble protein, esterase, dipeptidyl aminopeptidase II, and proteinase inhibitor.

The content of soluble protein, nonspecific esterase, dipeptidyl aminopeptidase II (DAP II), and proteinase inhibitors was compared for alveolar (AM) and peritoneal (PM) wash cells of rats. The cells present in the wash fluids were 85-90% macrophages in the peritoneal wash and 95% in the alveolar wash. Macromolecular components were resolved from whole cell homogenates by polyacrylamide gel isoelectric focusing (PAGIF) on horizontal gels and were identified cytochemically. Banding patterns clearly indicated a larger number of esterase zones in peritoneal compared to alveolar macrophages and ten previously unrecognized isozymes of DAP II in peritoneal macrophages with only three evident in their alveolar counterparts. (On whole blood smears, these cytochemically demonstratable enzymes were limited to macrophages, although DAP II was seen also in some mast cell granules). A protein band similar to the M6 band of alpha-1-antitrypsin in human serum was seen both in alveolar and peritoneal wash preparations. In addition, nine other major trypsin-binding protein bands were observed in the peritoneal macrophages, including two bands not observed in the alveolar macrophage extracts.

Animals↗
PubMed1980

Prehepatic insulin production in man: kinetic analysis using peripheral connecting peptide behavior.

The prehepatic production of insulin in normal man was evaluated by kinetic analysis of connecting peptide (C-peptide) behavior in the plasma in men and women. Studies were performed during suppression of endogenous insulin secretion (induced by both fasting and exogenous insulin injection) as well as during stimulation of secretion (induced by oral glucose ingestion) and iv glucose injection. Least squares spline fitting of the C-peptide data by interactive computer analysis permitted evaluation of the precursor production of insulin using a two-compartment model for C-peptide removal. Basal prehepatic insulin production averaged 15-4 mU/70 kg.min in 20 subjects and was reduced to 0.9 +/- 2.2 mU/70 kg.min after 84 h of fasting. The injection of exogenous iv insulin resulted in suppression of endogenous production to 0 +/- 2.5 mU/70 kg.min. Maximum prehepatic insulin production induced by a 100-g oral glucose tolerance test was 91 +/- 1.2 mU/70 kg.min, with a cumulative hormone secretion of 11.4 +/- 2.0 U over the 5 h of observation. After the acute iv injection of 25 g glucose, production rose to 465 +/- 108 mU/70 kg.min at 2 min post injection and rapidly returned toward basal. Levels of insulin in the portal vein calculated from this analysis were markedly elevated relative to simultaneous peripheral venous levels. These results quantitate prehepatic insulin production and portal venous insulin concentration from an analysis of the behavior of C-peptide within the plasma in both the steady state and the nonsteady state in man.

Adult↗
PubMed1980

Alterations in pentobarbital and meperidine pharmacokinetics induced by bile duct ligation in the rat.

Although impaired microsomal drug metabolism has been demonstrated in response to bile duct ligation, there has been little previous assessment of the effects of extrahepatic biliary obstruction on drug pharmacokinetics in vivo. In this study, the effects of bile duct ligation on overall disposition on pentobarbital and meperidine in the rat have been assessed in vivo and in isolated perfused rat livers. A significant reduction in clearance of both compounds was seen in response to bile duct ligation. No change in protein binding of either drug was demonstrated, but alterations in initial volume of distribution of both drugs occurred in response to extrahepatic biliary tract obstruction. A significant reduction in the rate of perfusate flow was also seen in perfused liver experiments using livers from animals with previous bile duct ligation. Reduction in clearance of both a high extraction drug (meperidine) and a lower extraction drug (pentobrbital) in response to bile duct ligation suggests that both hepatic blood flow and drug metabolizing enzyme activity may be altered by extrahepatic biliary tract obstruction.

Animals↗
PubMed1979

Synthesis of hemoglobin Aic and related minor hemoglobin by erythrocytes. In vitro study of regulation.

Factors that influence hemoglobin (Hb)A(Ic) synthesis by intact erythrocytes were studied in vitro. After incubation cells were lysed, and hemoglobins were separated by isoelectric focusing on polyacrylamide slab gels and quantitated by microdensitometry. HbA(Ic) increased with time, glucose concentrations (5-500 mM), and incubation temperature (4 degrees -37 degrees C). Low temperatures allowed prolonged incubations with minimal hemolysis. At 4 degrees C HbA(Ic) increased linearly with time for 6 wk; after incubation at the highest glucose concentration, HbA(Ic) comprised 50% of total hemoglobin. Insulin (1 and 0.1 mU/ml) did not affect HbA(Ic) synthesis in vitro. In addition to glucose, galactose and mannose, but not fructose, served as precursors to HbA(Ic). A good substrate for hexokinase (2-deoxyglucose) and a poor hexokinase substrate (3-O-methylglucose), were better precursors for HbA(Ic) synthesis than glucose, suggesting that enzymatic phosphorylation of glucose is not required for HbA(Ic) synthesis. Autoradiography after erythrocyte incubation with (32)P-phosphate showed incorporation of radioactivity into HbA(Ia1) and A(Ia2), but not HbA(Ib), A(Ic), or A. Acetylated HbA, generated during incubation with acetylsalicylate, migrated anodal to HbA(Ic) and clearly separated from it. Erythrocytes from patients with insulinopenic diabetes mellitus synthesized HbA(Ic) at the same rate as controls when incubated with identical glucose concentrations. Likewise, the rate of HbA(Ic) synthesis by erythrocytes from patients with cystic fibrosis and congenital spherocytosis paralleled controls. When erythrocytes from cord blood and from HbC and sickle cell anemia patients were incubated with elevated concentrations of glucose, fetal Hb, HbC, and sickle Hb decreased, whereas hemoglobins focusing at isoelectric points near those expected for the corresponding glycosylated derivatives appeared in proportionately increased amounts.

Adult↗
PubMed1979

Cytochemical localization and biochemical characterization of dipeptidyl aminopeptidase II in macrophages and mast cells.

Dipeptidyl aminopeptidase II (DAP II) was demonstrated cytochemically at light and electron microscope levels in rat macrophages and mast cells using Lys-Ala-4-methoxy-2-naphthylamide as a specific substrate. The enzyme which was found to be lysosomal in both cell types, was analyzed biochemically in extracts by measuring fluorometrically the liberated naphthylamine, and was visualized in sections microscopically using azo-coupling methods. DAP II was further characterized by isoelectric focusing techniques. Macrophage DAP II was found to be typical of that found in other rat tissues in terms of its structural latency, substrate specificity, inhibitor sensitivities, and pH activator requirements. Addition DAP II isozymes, not previously recognized, were observed.

Animals↗
PubMed1979

Demonstration of alpha 1-antitrypsin by immunofluorescence on paraffin-embedded hepatic and pancreatic tissue.

Studies were performed in an attempt to improve current immunohistological techniques for the demonstration of alpha 1-antitrypsin (A1AT) in formalin-fixed paraffin-embedded tissues. The unwanted fluorescence (UF) commonly occurring in such procedures was found to be effectively eliminated by immunoadsorption of A1AT antisera with human serum lacking A1AT (Pi-null phenotype) coupled in solid phase to glutaraldehyde-activated aminohexyl-Sepharose 4B. Specificity of the antisera for A1AT was established by subsequent solid phase immunoadsorption against normal human serum bound to AH-Sepharose 4B. Using these techniques, immunoreactive A1AT was demonstrated in the cytoplasm of hepatocytes in liver biopsies obtained from patients with Z and MZ serum phenotypes, and in the cytoplasm of normal pancreatic islet cells.

Animals↗
PubMed1979

Segregation distortion of the alpha 1-antitrypsin Pi Z allele.

alpha 1-antitrypsin (alpha 1AT) of the Pi type Z is associated with two diseases: pulmonary emphysema and cirrhosis of the liver. We report 23 families with both parents heterozygous for the PiZ allele, characterized from our own analysis and from world literature sources. All families were identified through members expressing disease. From the extended pedigrees, 18 backcross families (parents with Pi types MM and MZ) were identified. Analysis of the backcross families reveals a significant increase in Pi MZ offspring (.73) among families where the male is heterozygous. The distortion is not detected among families where the female is heterozygous. Among the matings where both parents are heterozygous, we found 0.43 Pi ZZ from families where one or more members expressed hepatic cirrhosis, and 0.40 Pi ZZ for total families studied. This contrasts to the 0.25 Pi ZZ expected, but is consistent with the distortion observed in backcross matings. The implications of various statistical approaches are discussed, and we point out why our findings differ from previous reports. We suggest a possible biological explanation residing in the fertilization process.

Alleles↗
PubMed1978

Fendosal (HP 129): a potent anti-inflammatory and analgesic compound.

Fendosal (HP 129) is one of a series of potent non-steroidal anti-inflammatory agents. Fendosal was compared with aspirin in several anti-inflammatory and analgesic bioassay procedures. Results indicate that fendosal has an anti-inflammatory activity 1.4 times greater than does aspirin in carrageenan-induced rat paw edema. Fendosal is 6.9 to 9.5 times more active than aspirin in the prophylactic and therapeutic adjuvant-induced polyarthritis models of chronic inflammation. The analgesic activity of fendosal is considered to be superior to that of aspirin, with the advantage of a prolonged duration of action. The gastric-irritating properties of fendosal are very low in comparison with those of aspirin. Fendosal has a much wider separation of effective and gastric-irritating doses than does aspirin.

Animals↗
PubMed1978

Effects of certain antitumor platinum compounds on kidney esterases.

In a study of the biochemical mechanism of renal toxicity of certain antitumor platinum compounds, particularly cis-dichlorodiammineplatinum(II) (NSC-119875), qualitative and quantitative studies of the soluble nonspecific kidney esterases were carried out using (C57BL/L X DBA/2) mice. There was a major suppression of the testosterone-dependent esterases of treated male mice; these levels dropped to levels below those found in untreated females within 72 h after certain of the drugs were administered. This effect appeared to be in inverse relationship to the numerical value of the LD50 values of the compounds investigated.

Animals↗
PubMed1978

Synthesis of spiro[isobenzofuran-1(3H),4'-piperidines] as potential central nervous system agents. 4. Central nervous system depressants.

The synthesis of 1'-[3-(4-fluorobenzyoyl)propyl]-3-phenylspiro[isobenzofuran-1(3H),4'-piperidine] (2a) and eight halo and methoxy analogues is described. The compounds were generally more potent per os than chlorpromazine in the Sidman avoidance paradigm in rats and less potent than haloperido. 1'-[3-(4-Fluorobenzoyl)propyl]-3-(4-fluorophenyl)spiro[isobenzofuran-1(3H),4'-piperidine] (2e) approached the per os potency of haloperidol in this test and was shown to be active in inhibiting monkey avoidance also. Compound 2e was much less active than haloperidol in antagonizing apomorphine-induced emesis in dogs, apomorphine-induced stereotypy in rats, and amphetamine-induced circling in lesioned rats. This lack of nonselective, dopamine-receptor blocking effects makes 2e attrative as a potential neuroleptic.

Amphetamine↗
PubMed1978

A simplified assay of hemoglobin AIc in diabetic patients by use of isoelectric focusing and quantitative microdensitometry.

Isoelectric focusing (IEF) of human erythrocyte hemolystaes on polyacrylamide slab gels over a pH gradient of 6 to 8 provides sufficient resolution of hemoglobin AIc (HbAIc) from other hemoglobin components (AIa, AIb, AII, S, and F) to allow quantification by high-resolution microdensitometry. Twice-chromatographed HbAIc alone and in admixtures with normal and diabetic hemolysates were employed to verify the identification and quantification of the AIc component. Relative concentration was determined as a per cent of the total hemoglobin absorption at 556 nm on acid-fixed, unstained gels. A total of 60 patient samples were examined by IEF, and, for 35 samples, both column chromatography and IEF determination were obtained, revealing excellent correlation between these two methods.

Blood Protein Electrophoresis↗