Increase in glucose-stimulated insulin release and insulin biosynthesis in isolated pancreatic islets from D-galactosamine-treated rats

Insulin secretion in response to glucose, glucose-stimulated insulin biosynthesis and insulin content was studied in pancreatic islets freshly isolated from male Wistar rats (150-200 g) with galactosamine-induced hepatitis. Animals were sacrificed by decapitation 3, 6, 12 and 24 hours after a single intraperitoneal injection of 500 mg/kg of galactosamine. Isolated islets prepared by collagenase method were perifused in Swim's medium with 20 mM glucose at 37 degrees C up to 30 minutes. Samples were taken at 2-10 min intervals for insulin assay. Insulin biosynthesis was assessed by the incorporation of [3H]-leucine into immunoprecipitable products (insulin and proinsulin) in pancreatic islets after 120 min incubation with 20 mM glucose. Glucose-stimulated insulin secretion was significantly increased at 6, 12 and 24 hours following the administration of galactosamine compared to control. The rate of insulin biosynthesis was stimulated to 170, 138 and 185% of control level 3, 6 and 12 hours after galactosamine-treatment, respectively. Significant increase in insulin content of islets was found 24 hours after galactosamine treatment, following the increased insulin biosynthesis. The present results indicate that pancreatic B cell function is activated in early stage of acute liver injury.

Suicide by captopril overdose

We report a case of a 75 year-old male who committed suicide by taking an overdose of captopril. He took approximately ninety 12.5 mg captopril tablets. The postmortem plasma concentration of captopril was 60.4 mg/L. A review of the medical literature revealed five cases of captopril overdose all from unsuccessful suicide attempts. To our knowledge, this is the first case report of fatal captopril overdose with the measurement of plasma concentration of the drug.

Morphological characterization of surface-induced platelet activation

Morphological changes of platelets activated on glass and dimethyldichlorosilane-treated glass were investigated using video microscopy. The platelet morphological changes were quantified by measuring the area and circularity of spreading platelets. In addition, re-organization of cytoskeletal structures of spread platelets was examined. The effects of precoated albumin and fibrinogen on the platelet spreading kinetics were examined as a function of surface protein concentrations. Results showed that platelet shape changes were very sensitive to the surface concentration of precoated proteins. In general, platelets on fibrinogen-precoated surfaces spread fully to a circular shape and developed an extensive inner filamentous zone. In the presence of albumin on the surface, however, platelets could not spread fully and the development of the inner filamentous zone was very poor. For both albumin and fibrinogen, the maximum effects of precoated proteins on platelet shape changes were observed when the surface protein concentration reached the monolayer concentration.

A multistate model for coronary heart disease--an application to different prevention strategies

"The discrete-time stochastic model presented in this paper pays attention [to] the association between physiological risk factors and [coronary heart disease] morbidity as well as mortality trends. Transition probabilities are modeled as a polychotomous logistic function of risk factors. A series of separate simple logistic regression analyses...are performed as a replacement for estimating polychotomous logistic regression parameters. Data from the Finnish North Karelia Project is used to test the model." (SUMMARY IN KOR)

Immunophenotypic spectrum of plasma cell leukemia

Four cases of plasma cell leukemia (PCL) are reported that illustrate the variable immunotype of this disorder in contrast with the immunologic profile described for normal B-cell maturation and typical multiple myeloma (MM). Mature B-lymphocytes express B1 antigen (Ag) and surface immunoglobulin (SIg) whereas maturation to the plasma cell stage is accompanied by loss of these immunologic markers and expression of T10 Ag, plasma cell Ag (PCA), and cytoplasmic immunoglobulin (CIg). Plasma cells from patients with MM have previously been found to express the immunophenotype of normal plasma cells. In contrast, none of the four cases reported here express an immunologic profile typical for specific B-cell differentiation stages. Only one of four cases was strongly positive for PCA but additionally expressed B1 Ag and SIg. Of the remaining three cases, all expressed T10 Ag and CIg; two cases also expressed SIg, weak PCA, and B1 Ag. All four cases were monoclonal for lambda light chains and negative for common ALL Ag (CALLA). The variable expression of mature B-cell markers and plasma cell markers demonstrates the immunophenotypic spectrum of PCL; the prognostic significance of this heterogeneity needs to be more closely examined.

CHAPS solubilization of a G-protein sensitive 5-HT1A receptor from bovine hippocampus

The binding of [3H] 8-OH-DPAT to membrane-bound 5-HT1A receptors from bovine hippocampus was saturable and corresponded to a single high-affinity state. Solubilization of the bovine hippocampal membranes with 10 mM CHAPS containing 200 mM NaCl, renders a preparation which binds [3H] 8-OH-DPAT with high-affinity (Kd = 1.9 nM) and is guanine nucleotide sensitive and ketanserin insensitive. 50% of [3H] 8-OH-DPAT binding activity is solubilized. The presence of GMP-P(NH)P promotes a low-affinity (Kd = 9.6 nM) state which is characteristic of receptors coupled to G-proteins. GMP-P(NH)P markedly accelerates the dissociation [3H] 8-OH-DPAT from solubilized membranes while having negligible effects on association. Thus, the agonist can activate the terniary complex rather than to promote its formation. 8-OH DPAT, WB 4101 and 5-carboxamidotryptamine dose responsively inhibit soluble [3H] 8-OH-DPAT binding with IC(50) values of 16.1, 15.6 and 1.3 nM, respectively. The CHAPS solubilized membrane preparation retains many of the [3H] 8-OH-DPAT binding characteristics of the membrane bound form.

Simulation of a population-based model of coronary heart disease morbidity and mortality

"The main objective of this study is to develop a modelling strategy useful to examine and predict major trends in coronary heart disease. Once we develop a model which can mimic population changes over time, then the models can be extended to provide information on intervention effects by changing the risk factors." The model is illustrated using data for North Karelia, Finland, for the period 1972-1978. (SUMMARY IN KOR)

Mechanisms of mucoadhesion of poly(acrylic acid) hydrogels

It has been proposed that mucoadhesives which adhere to the gastric mucus layer may be used to prolong gastric retention time of oral dosage forms. Preliminary studies, using acrylic hydrogels, have established that the density of carboxyl groups on the polymer chain is important for mucoadhesion. To understand the role(s) of the carboxyl groups in mucoadhesion, acrylic acid-acrylamide random copolymers [P(AA-co-AM)] were synthesized, and the adhesion strength of the cross-linked polymers to the gastric mucus layer was examined as a function of the pH, initial concentration of the cross-linking agent, degree of swelling, and carboxyl-group density. From the study on mucoadhesion of various P(AA-co-AM), it was found that at least 80% of the vinyl groups of the polymer must possess carboxyl groups in the protonated form. The dependence of mucoadhesion on pH and carboxyl-group density suggests that mucoadhesion occurs through hydrogen bonding. In addition, the density of the cross-linking agent significantly affects mucoadhesion. As the density of the cross-linking agent is lowered, the mucoadhesive strength increases, although the density of carboxyl groups in the test surface area is reduced. It is concluded that for mucoadhesion to occur, polymers must have functional groups that are able to form hydrogen bonds above the critical concentration (80% for vinyl polymers), and the polymer chains should be flexible enough to form as many hydrogen bonds as possible.

Bacterial peptidoglycan induces in vitro rheumatoid factor production by lymphocytes of healthy subjects

The present studies were carried out to further characterize the polyclonal B cell activating properties of bacterial peptidoglycan (PG) and to determine if this ubiquitous agent induces in vitro IgM rheumatoid factor (RF) production by lymphocytes from healthy volunteers. Peripheral blood mononuclear cells (PBMC) were cultured in the presence of peptidoglycan, pokeweed mitogen (PWM), a standard polyclonal B cell activator, or additional culture medium. Supernatants were harvested on days 7-8 for determination of total IgM, total IgG, and IgM RF by an enzyme-linked immunosorbent assay (ELISA). PG and PWM induced comparable amounts of total IgM production but PG was a less potent stimulant of total IgG production. PG induced in vitro IgM-RF production in 9/33 experiments, a frequency of response of less than that observed in corresponding PWM stimulated cultures (22/33 experiments). PG-induced IgM-RF production depended upon active protein synthesis and did not correlate with the magnitude of PG-induced total IgM production. The latter finding suggests that PG-induced IgM-RF may not merely reflect polyclonal B cell activation. These results add to a growing list of PG's functional properties and provide further impetus for considering this ubiquitous agent as a potential stimulant for in vivo RF production.

Bioadhesive polymers as platforms for oral controlled drug delivery II: synthesis and evaluation of some swelling, water-insoluble bioadhesive polymers

A series of cross-linked, swellable polymers was sythesized from monomers such as acrylic acid, methacrylic acid, and others with various cross-linking agents to produce a range of polymers differing in charge densities and hydrophobicity. The densities, rate, and extent of hydration of the polymers were determined. An increase in the number of hydrophobic groups in the polymer structure reduced hydration whereas the density of the polymer was unaffected. A sensitive in vitro method for measuring adhesion of polymer to tissue from the rabbit stomach was developed. Polymers of acrylic acid loosely cross-linked (0.3%, w/w) with three different agents, divinyl glycol, 2,5-dimethyl-1,5-hexadiene, and divinylbenzene, showed the same degree of bioadhesion while poly(methacrylic acid-divinylbenzene) showed reduced bioadhesion. The small percent of cross-linking agent, irrespective of physicochemical properties, did not contribute substantially to bioadhesion, whereas the starting monomer had a large effect. The effect of pH on the bioadhesion of poly(acrylic acid-divinyl glycol) was studied at constant temperature, ionic strength, and osmolality. The polymer showed maximum adhesion at pH 5 and 6 and a minimum at pH 7. Gastrointestinal transit studies of cross-linked polymers in rats were studied. Poly(acrylic acid-divinyl glycol) and poly(methacrylic acid-divinylbenzene) were shown to have substantially longer GI transit times than the control, Amberlite 200 resin beads. The delay in transit time was due to bioadhesion of the polymer to the mucin-epithelial cell surface which was clearly observable on animal autopsy. The acrylic acid polymer showed a longer GI transit time than the methacrylic acid polymer, and this in vivo GI transit result is consistent with in vitro bioadhesion test results.

Antibodies to peptidoglycan in patients with spondylarthritis: a clue to disease aetiology?

Although the aetiology of the spondylarthritic diseases, ankylosing spondylitis and Reiter's syndrome, is obscure, a clue to the pathogenesis might be an animal model, adjuvant arthritis. Rats with this disease develop a spectrum of pathology with marked similarity to the spondylarthritides. Since peptidoglycan, a major cell wall component of most bacteria is causally implicated in adjuvant arthritis, we sought evidence that peptidoglycan exposure accompanies both Reiter's syndrome and ankylosing spondylitis. Antibodies to the D-Ala-D-Ala moiety of peptidoglycan were measured by a sensitive and specific ELISA. Antibodies were elevated significantly in patients with ankylosing spondylitis or Reiter's syndrome, but not in patients with rheumatoid arthritis or degenerative joint disease in comparison with normal controls. The findings should be considered preliminary, since only a minority of patients had increased antibody titres. However, the findings are compatible with the hypothesis that peptidoglycan is causally related to spondylarthritis. Antibodies to other moieties in the peptidoglycan molecule might be a more sensitive test for significant exposure.

Detection of soluble peptidoglycan in urine after penicillin administration

A unique enzyme-linked immunosorbent assay was developed to detect soluble peptidoglycans in biological fluids. It makes use of the similar affinities of vancomycin and purified rabbit antibodies to peptidoglycan precursor sequences found in soluble peptidoglycans. This assay has been used to detect as little as 500 pg of soluble peptidoglycan per ml of serum and 5 pg/ml of urine. Studies of normal individuals and Staphylococcus aureus-infected patients revealed only a few sera with detectable levels of soluble peptidoglycans. Studies of normal volunteers who were given a single oral dose of 250 mg of penicillin VK showed that about half had detectable levels of soluble peptidoglycans in their urine up to 6 h after ingestion. This suggests that soluble peptidoglycans can be released by indigenous bacteria in detectable amounts. In one volunteer, a detectable level of soluble peptidoglycan in the urine at 6 h decreased to an undetectable level at 12 h. Such an ephemeral appearance of soluble peptidoglycan in the urine could account for the small number of human sera that had detectable levels of soluble peptidoglycan.

Far-infrared laser scattering studies of density fluctuations in tokamak fusion plasmas

Development of a far-infrared Thomson scattering system for the study of density fluctuations in fusion plasmas is described. New data are presented of naturally occurring low-frequency microturbulence and also of electrostatic modes generated at the ion cyclotron range of frequencies (ICRF). The latter studies are important in understanding ICRF supplementary heating experiments. They have produced the first internal observation of mode-converted ion -Bernstein waves in a tokamak plasma.

A simple washing technique for solid-phase radioimmunoassays and enzyme-linked immunosorbent assays

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High resolution optical ranging system

An optical ranging system which can see through opaque material has been demonstrated. It uses picosecond pulses, generated in a mode-locked dye laser for viewing and, as a very fast gate, a second frequency offset pulse train with a variable delay at the detector. The system could detect a reflection from a mirror inside an opaque mixture with 64-dB round-trip loss and with 1.7-mm range resolution. Transverse resolution of 0.1 mm was also observed. With certain obvious changes in instrumentation this could be converted into a scanning device. The present depth of penetration (round-trip attenuation) would correspond to 0.67 cm in human tissue.

Chromosomal mapping of human creatine kinase (brain type) using human-rodent somatic cell hybrids

Concordant segregation of human brain-type creatine kinase, CK(BB), expression with nucleoside phosphorylase (NP) expression and the presence of chromosome 14 was observed in 53 independently derived cell hybrids between CK(BB)-positive human cells and CK(BB)-negative rodent cells. Further analysis of 26 subclones of two CK(BB)-positive human-mouse cell hybrids confirmed the positive correlation of CK(BB) expression with NP expression. The results suggest that the gene coding for human CK(BB) can be assigned to chromosome 14.

New technique for solid-phase immunoassay: application to hepatitis B surface antigen

I describe a new technique for improving the sensitivity of the solid-phase "sandwich" assay, by using the through-passage receptacle in a novel flow-communication device. The technique allows a large volume of serum to flow through the antibody-coated receptacle repeatedly during the incubation and is thus termed the "flow-through large-volume incubation" method. Binding of 125I-labeled hepatitis B surface antigen to its corresponding antibody on a solid-phase by this method was more rapid and persistent than binding by the conventional method. When the method was applied to the first incubation of the sandwich assay, the test for the antigen was rendered four-, eight-, and 32-fold as sensitive as an accepted third-generation test for the antigen, by incubating 5-mL volumes of serum at (a) room temperature for 18 h, (b) 45 degrees C for 8 h, or (c) room temperature for seven days, respectively.

Thrombotic thrombocytopenic purpura in early pregnancy. Remission after plasma exchange

A 24-year-old Chinese female developed fever, fluctuating neurological and renal manifestations, microangopathic hemolytic anemia, and thrombocytopenia during the 11th week of her first pregnancy. Therapy for thrombotic thrombocytopenic purpura (TTP), initiated during the 15th week of her pregnancy, including corticosteroids, platelet aggregation inhibitors, hysterotomy, and splenectomy was ineffective. However, dramatic improvement and remission occurred after plasma exchange of 3,560 ml was performed with the Haemonetics Model 30 Blood Cell Separator.

New technique for solid-phase immunoassay: application to hepatitis B surface antigen

I describe a new technique for improving the sensitivity of the solid-phase "sandwich" assay, by using the through-passage receptacle in a novel flow-communication device. The technique allows a large volume of serum to flow through the antibody-coated receptacle repeatedly during the incubation and is thus termed the "flow-through large-volume incubation" method. Binding of 125I-labeled hepatitis B surface antigen to its corresponding antibody on a solid-phase by this method was more rapid and persistent than binding by the conventional method. When the method was applied to the first incubation of the sandwich assay, the test for the antigen was rendered four-, eight-, and 32-fold as sensitive as an accepted third-generation test for the antigen, by incubating 5-mL volumes of serum at (a) room temperature for 18 h, (b) 45 degrees C for 8 h, or (c) room temperature for seven days, respectively.

A new plastic receptacle for solid phase immunoassays

A new, simple, inexpensive plastic device for solid phase immunoassay, the through-passage receptacle (TPR), with a large ratio of surface area to volume, is described. It was substantially more efficient in non-specific protein adsorption and specific immunological binding than the conventional wells of microtiter plates. It was also easier to wash since washing was facilitated by a through-passage with a gravity flow. This device, which should be more conducive to automation than currently used receptacles, should increase the sensitivity and decrease the incubation time of the solid phase immunoassay technique.

Studies of the precipitating antibody response in pulmonary aspergillosis

Fractions of <i>Aspergillus fumigatus </i>obtained by DEAE-cellulose chromatography were used for studying the precipitating antibody in sera from four patients with bronchopulmonary aspergillosis (BPA) and in an additional patient with a pulmonary aspergilloma. Three of the 4 BPA sera demonstrated the precipitin reaction with one or more fractions in gel diffusion, but no individual pattern was identical. In order to further evaluate the nature of the precipitating antibody, the mold fractions prior to testing were exposed to either heat, papain, or to reduction and alkylation. The serum from one subject continued to show a precipitin response in gel in spite of antigen treatment, whereas heating and reduction and alkylation abolished a detectable precipitin reaction by the other two sera. Papain had no apparent effect upon any of the antigens tested. In contrast to BPA, the serum from a subject with an aspergilloma contained multiple precipitating antibodies to the mold fractions studied. These antibodies were developed against antigens which showed varying degrees of lability when exposed to either heat or to reduction and alkylation.