Macrophages enhance binding of beta-VLDL and cholesterol ester accumulation in cultured aortic smooth muscle cells

Summary The effect of macrophages on the uptake of -very low-density lipoprotein (-VLDL) by smooth muscle cells (SMC) expressing different morphological phenotypes was examined in culture. The SMC were grown alone and in co-culture with macrophages for four days, then incubated with different concentrations of¹²⁵I--VLDL for 3 h at 4°C or with 75 ug/ml -VLDL for 24h at 37°C. The binding of -VLDL to SMC at 4°C was enhanced in the presence of macrophages irrespective of the phenotype expressed by SMC. This occurred through modification of the lipoprotein, since binding of re-isolated macrophage-conditioned -VLDL to SMC was 12.5 times that of fresh -VLDL. This modified form of -VLDL competed with fresh -VLDL for binding to SMC. Binding was inhibited in the presence of probucol, suggesting that an oxidative mechanism may be involved.The presence of macrophages also enhanced the accumulation of -VLDL-derived cholesterol in SMC. While most of this is a consequence of the enhanced binding, macrophages may also act directly on SMC to increase cholesterol accumulation, since the activity of acid cholesterol ester hydrolase and neutral cholesterol ester hydrolase in SMC was reduced in the presence of macrophages.     

Diagnosis of the mucopolysaccharidoses using cultured skin fibroblasts and amniotic fluid cells

Assay of-L-iduronidase, heparin sulphamidase,N-acetyl--D-glucosaminidase, arylsulphatase B,-L-fucosidase,-glucuronidase,-galactosidase and-D-mannosidase in cultured cells is described. Activities in deficient fibroblast strains are compared to control fibroblast strains. The first case of Sanfilippo B in the United Kingdom is reported. A comparison of enzyme activities in cultured fibroblasts and amniotic fluid cells is made.     

α- andβ-mannosidoses

Summary Clinical, pathological and biochemical findings in the mannosidoses are described. Family studies showed granulocyte-rich white cell fractions to be the tissue of choice for carrier detection in-mannosidosis. Metabolic labelling studies using [³H] mannose demonstrated accumulation of Man1-4GlcNAc in cultured skin fibroblasts from a patient with this condition. Alternative methods of egress from lysosomes were suggested for this compound by its secretion into culture medium and apparent reduction of storage with time in cultures.-mannosidase deficient goats are not thought to be a true animal model of the human condition, as although they showed a similar enzyme deficiency, the clinical presentation is much more severe and the major storage material (Man1-4GlcNAc1-4GlcNAc) is different.     

Uptake and metabolism of radiolabelled GM1-ganglioside in skin fibroblasts from controls and patients with GM1-gangliosidosis

Summary The uptake and metabolism of [3-³H-sphingosine]GM1-ganglioside was measured in cultured skin fibroblasts from controls and patients with infantile, juvenile and adult GM1-gangliosidosis. When dissolved in medium with phosphatidylserine, GM1-ganglioside was efficiently taken up by cultured skin fibroblasts and transferred into lysosomes. A linear increase in GM1-ganglioside endocytosis was shown with phosphatidylserine concentrations of up to 40m/ml. A pulse-chase study revealed that [³H]GM1-ganglioside was metabolized to GM2-ganglioside, GM3-ganglioside, ceramide dihexoside, ceramide monohexoside, ceramide and sphingosine. Sphingosine was recycled to sphingomyelin. In a 20-h pulse study, cell lines from patients with GM1-gangliosidosis of infantile, juvenile and adult types hydrolysed 2–5%, 20–44% and 54–58% of the total endocytosed GM1-ganglioside respectively. These values were lower than in control cells (64.17 ± 5.43% (n=10)). The hydrolysis rates of exogenous [³H]GM1-ganglioside in cultured fibroblasts from patients with various types of GM1-gangliosidosis closely reflected the clinical severity.Abbreviations GM1 Gal13GalNAc14(NeuAc23)Gal14Galc-1-ceramide - GM2 GalNAc14(NeuAc23)Gal14Glc-1-ceramide - GM3 NeuAc23Gal14Glc-1-ceramide - CDH Gal14Glc-1-ceramide     

Differential interleukin-1 receptor antagonism on pancreatic beta and alpha cells. Studies in rodent and human islets and in normal rats

Summary The monokines interleukin-1 and - have been implicated as effector molecules in the immune-mediated pancreatic beta-cell destruction leading to insulin-dependent diabetes mellitus. Here we investigated the effects of interleukin-1 receptor antagonism on insulin and glucagon release of rat, mouse and human islets exposed to recombinant human interleukin-1, and on interleukin-1 induced changes in blood glucose, serum insulin and serum glucagon levels in Wistar Kyoto rats. The interleukin-1 receptor antagonist reduced the co-mitogenic effect of interleukin-1 on mouse and rat thymocytes with a 50% inhibitory concentration of 10- and 100-fold molar excess, respectively. Complete inhibition was obtained with a 100–1,000-fold molar excess. However, at a 100-fold molar excess the interleukin-1 receptor antagonist did not antagonise the potentiating effect of interleukin-1on rat islet insulin accumulation during 3 and 6 h of exposure or of interleukin-1-induced inhibition of insulin release after 24 h. In contrast, interleukin-1-stimulated islet glucagon release was completely antagonised by a 100-fold molar excess of interleukin-1 receptor antagonist. A 10,000-fold molar excess of interleukin-1 receptor antagonist was needed to antagonise interleukin-1 stimulatory and inhibitory effects on rat beta-cell function in vitro. A 100-fold excess of interleukin-1 receptor antagonist could not counteract interleukin-1 effects on mouse and human beta cells, excluding species difference in the efficacy of the human interleukin-1 receptor antagonist. An anti-mouse interleukin-1 receptor type I antibody completely abolished interleukin-1 effects on isolated mouse islets. A 10–100-fold molar excess of interleukin-1 receptor antagonist antagonised interleukin-1-induced fever, hypercorticosteronaemia and hyperglucagonaemia, but not interleukin-1-induced reduction in insulin/glucose ratio in normal rats. In conclusion, our results suggest that antagonism of interleukin-1 effects on beta cells requires higher concentrations of interleukin-1 receptor antagonist than those necessary to block interleukin-1 action on islet alpha cells and other interleukin-1 targets in vitro and in vivo. This may contribute to the understanding of the specificity of the immunological beta-cell destruction leading to insulin-dependent diabetes.     

Desensitization pattern of cardiac β-adrenoceptor subtypes by prolonged in vivo infusion of pindolol and celiprolol in rats

Summary The regulatory effects of pindolol and celiprolol on cardiac -adrenoceptor density were studied in vivo in order to assess the subtype selectivity of their partial agonistic activity (PAA). The substances were continuously administered to rats for 1 week by means of implanted osmotic minipumps. The density of -adrenoceptor subtypes were estimated from ICYP saturation binding experiments performed on cardiac ventricular plasma membranes in the presence of a highly selective antagonist (CGP 20172 A or ICI 118,551). Both antagonists were employed at concentrations as high as to block one subtype only without affecting the complementary subtype. For control purposes, rats were also treated with isoprenaline (0.4 mg/kg/h) and propranolol (0.15 mg/kg/h), or vehicle. Pindolol (0.036 mg/kg/h) and celiprolol (0.36 mg/kg/h) reduced the density of ventricular ₂-adrenoceptors by 46% and 23%, respectively, which — in the case of pindolol — was significant when compared to the non-treated controls. Both compounds, however, produced a small, but distinct increase in the number of ₁-adrenoceptors by approximately 26%. This finding is in contrast to the propranolol-induced upregulation of both ₁- and ₂-adrenoceptors by approximately 80%. Since supramaximal doses of each drug were administered, a significant smaller increase of ₁-adrenoceptors by pindolol and celiprolol —as compared to the increase produced by propranolol — can be interpreted as evidence for a PAA of pindolol and celiprolol on ₁-adrenoceptors as well. Isoprenaline as a full agonist caused a marked loss of of both -adrenoceptor subtypes. Although it exhibits equal affinity at both subtypes the decrease amounted to 80% of the ₂- but only to 54% of the ₁-adrenoceptors density. This indicates that the down-regulation of cardiac -adrenoceptors in general seems to be more pronounced at the ₂-than at the ₁-adrenoceptors population. We conclude that the subtype desensitization pattern of agents with intrinsic activity precludes the determination of subtype-selectivity, since ₁- and ₂-adrenoceptors appear to differ in their sensitivity presumably as a result of subtype specific baseline desensitization produced by endogenous catecholamines.     

Serum β2-Microglobulin in Chronic Hepatitis C

₂-Microglobulin(₂-MG) plays a key role in influencingthe immune response to viral infections as it is anintegrating part of the main histocompatibility system(HLA). We attempted to evaluate the changes in class I HLA antigens bycomparing the serum ₂-MG behavior in agroup of patients affected by chronic hepatitis C withthat observed in a group of healthy controls. Our studyrevealed that the patients presented higher serumbeta-MG levels than healthy controls (P = 0.0003).beta-MG levels were correlated with duration and degreeof the disease. Furthermore, there was a statisticallysignificant correlation between ₂-MG andHCV RNA levels, while no correlations were observedbetween serum ₂-MG levels and HCVgenotypes. The increment in serum ₂-MGvalues accompanying the progression of liver disease may be an expression ofaugmented production rather than alteredexcretion.     

β-Mannosidase deficiency: Heterogeneous manifestation in the first female patient and her brother

Summary -Mannosidase deficiency was demonstrated in fibroblasts of a girl who showed severe psychomotor retardation, bone deformities and gargoylism and recurrent skin and respiratory infections and who died at 20 years of age from bronchopneumonia. This first demonstration of a female patient confirms the autosomal recessive inheritance of -mannosidosis. Further investigation of this gipsy family revealed -mannosidosis in an older brother with a milder manifestation of gargoyl facial dysmorphology, mental retardation, hearing impairment and recurrent infections. -Mannosidase activity was completely deficient in his cultured skin fibroblasts, leukocytes and plasma. In urine a characteristic disaccharide was present. Heterozygote levels of -mannosidase were found in fibroblasts and/or plasma of the parents and one sister.     

The effects of parabiosis on serum and kidney glycosidase activities in spontaneously diabetic mice

Summary Spontaneously diabetic non-obese mice of the ICR strain were newly inbred in Shionogi laboratory, Japan. Animals became diabetic suddenly, more frequently and severely in females. Blood glucose levels were 452±73 mg/100 ml with serum insulin levels of < 1.0 U/ml in the fed state. Parabiosis with normal control ICR mice for 2 weeks decreased the blood glucose level to 260±51 mg/ 100ml (P<0.01) and resulted in serum insulin levels of 46.0±18.0 U/ml (P<0.01). Kidney homogenate -N-acetylglucosaminidase and -galactosidase activities were reduced in diabetic mice (42% and 44% decrease respectively) (P<0.025 and P<0.001), and restored almost to normal after 2 weeks of parabiosis. Renal -mannosidase activity was decreased 43% (P<0.001) in the diabetic mice but unaffected by parabiosis. Serum -N-acetylglucosaminidase, -galactosidase and -glucosidase activities were significantly increased in diabetic mice (179%; 233% and 58% increase respectively) (P<0.005, P<0.001 and P<0.001), and returned to normal with parabiosis.     

Down-regulated β-adrenoceptors in severely failing human ventricles: Uniform regional distribution,but no increased internalization

Summary In chronic heart failure cardiac -adrenoceptors are decreased. In this study we investigated whether a) in severely failing human ventricles -adrenoceptors are uniformly decreased or regional variations exist, and b) the -adrenoceptor decrease is caused by increased internalization or is a real loss in -adrenoceptors. For this purpose we assessed -adrenoceptor number and subtype distribution in a particulate fraction (mainly sarcolemmal plasma membranes) and a light vesicle fraction of right and left ventricular segments (obtained by cutting transversal, rings of 2 cm from the midventricular regions) of explanted hearts from 2 patients with end-stage congestive dilated cardiomyopathy (DCM) and one patient with end-stage ischemic cardiomyopathy (ICM). In all three hearts ventricular -adrenoceptor number was very low (7.5–10 and 21–26 fmol/mg protein in DCM, 15–22 fmol/mg protein in ICM compared to 68–74 fmol/mg protein in non-failing ventricles). -Adrenoceptors were uniformly decreased over the whole ventricular region and no considerable regional variations existed. The same held true for ₁- and ₂-adrenoceptors. In ICM decrease in -adrenoceptors was due to a concomitant reduction in ₁- and ₂-adrenoceptors, in DCM it was mainly caused by ₁-adrenoceptor down-regulation. In all ventricular segments investigated light vesicle -adrenoceptors amounted to about 5–7% of total ventricular -adrenoceptors and this was not significantly different from non-failing left ventricles. We conclude that a) in severely failing human ventricles -adrenoceptors are evenly down-regulated and no regional variations exist and b) the decrease in -adrenoceptors is not due to enhanced internalization but is a real loss of -adrenoceptors.Abbreviations DCM dillted cardiomyopathy - ICM ischemic cardiomyopathy - ICI 118,551 erythro-(±)-1-(7-methylindan-4-yloxy)-3-isopropylaminobutan-2-ol hydrochloride - CGP 12177 (±)-4-(3-tertiarybutylamino-2-hydroxypropoxy)-benzimidazole-2-on hydrochloride - ICYP (–) [¹²⁵I]-Iodocyanopindolol     

Detection of β-ureidopropionase deficiency with HPLC–electrospray tandem mass spectrometry and confirmation of the defect at the enzyme level

The pyrimidine bases uracil and thymine are degraded via the consecutive action of three enzymes to -alanine and -aminoisobutyric acid, respectively. To date, a number of patients have been described with a deficiency of dihydropyrimidine dehydrogenase and dihydropyrimidinase, the first two enzymes of the pyrimidine degradation pathway. In this study, we demonstrate that the first patient presenting with N-carbamyl--amino aciduria, due to a deficiency of -ureidopropionase, was easily diagnosed at the metabolite level using HPLC–tandem mass spectrometry. Urinary analysis showed strongly elevated levels of N-carbamyl--alanine and N-carbamyl--aminoisobutyric acid, with normal or moderately increased levels of the pyrimidine bases and the dihydropyrimidines, respectively. The deficiency of -ureidopropionase was confirmed by measuring all three enzymes of the pyrimidine degradation pathway. No activity of -ureidopropionase could be detected in a liver biopsy of the patient, while a normal activity of dihydropyrimidine dehydrogenase and dihydropyrimidinase was present. Thus, HPLC–tandem mass specrometry proved to be a powerful tool for the initial diagnosis of patients with deficiency of -ureidopropionase.     

Distribution of β-Adrenoceptor Subtypes in Gastrointestinal Tract of Nondiabetic and Diabetic BB Rats A Longitudinal Study

The effects of aging and diabetes on thedistribution of -adrenoceptor subtypes in the gutwere investigated in the BB rat.[¹²⁵I]Cyanopindolol binding to 10-msections was evaluated using film autoradiography. Cyanopindolol binding to -,₁-, and₂-adrenoceptors was displaced by 1M propranolol, 50 nM ICI-89-406, and 100 nMICI-118-551, respectively. -Adrenoceptor bindingwas highest in the circular muscle of proximal colon and lowest in thepylorus of 4- to 5-month-old rats. Aging (8- to10-month-old vs. 4- to 5-month-old rats) was associatedwith increased -adrenoceptor binding in thepylorus and reduced binding in the proximal colon.Diabetes had a time-dependent effect on the level of-adrenoceptor binding. It was increased in theantral and pyloric stomach but longer periods ofdiabetes caused a reduction in -adrenoceptorbinding in the pylorus. Those in the intestine werereduced time-dependently and involved₁- or ₂-adrenoceptorsor both.     

Beta lactamase resistance of newer cephalosporins and antimicrobial effectiveness against gram-negative bacilli

Summary Three newer cephalosporins (cefamandole, cefoxitin and cefazaflur) were investigated, in comparison with three older agents (cephalothin, cephaloridine and cefazolin) to determine their stability to -lactamases of gram-negative bacilli, and to correlate this with their antibacterial activity. Nine of the 17 bacterial strains employed produced broad-spectrum -lactamases; the remaining eight produced cephalosporinases. The cephalosporins were highly active against bacteria producing broad-spectrum -lactamases; they were less active against organisms producing cephalosporinases. All of the cephalosporinase-producing strains were resistant to cephalothin and cephaloridine. With the other cephalosporins the correlation between hydrolysis by cephalosporinases and resistance of the organisms was poor. Four of eight cephalosporinase-producing strains were resistant to cefoxitin, which was completely resistant to hydrolysis by the -lactamases. Cefozolin, cefamandole and cefazaflur inhibited several of these strains in spite of destruction by the -lactamase. Several cephalosporins need to be used in antimicrobial susceptibility testing of gram-negative bacilli.

---

Beta-Lactamase-Resistenz der neuen Cephalosporine und die antimikrobielle Wirksamkeit gegen gramnegative Bazillen

Zusammenfassung Drei neue Cephalosporine (Cefamandol, Cefoxitin und Cefazaflur) wurden im Vergleich zur drei älteren Präparaten der Cephalosporinreihe (Cephalothin, Cephaloridin und Cefazolin) untersucht, um ihre -Lactamase-Stabilität gegenüber gram-negativen Bazillen abzugrenzen und das Ergebnis mit ihrer antibakteriellen Aktivität zu korrelieren. Neun der 17 verwendeten Stämme produzierten Breitspektrum--Lactamasen. Die restlichen acht produzierten Cephalosporinasen. Die Cephalosporine waren hoch aktiv gegen breitspektrum--lactamase-produzierende Bakterien; sie waren weniger aktiv gegen Keime, die Cephalosporinase bildeten. Alle cephalosporinase-produzierenden Keime waren cephalothin-und cephalosporidin-resistent; bei den anderen Cephalosporinen war die Korrelation zwischen der Hydrolyse durch Cephalosporinasen und der Bakterienresistenz gering. Vier der acht cephalosporinase-produzierenden Stämme erwiesen sich als cefoxitin-resistent. Cefoxitin war jedoch komplett resistent gegenüber der -Lactamasehydrolyse. Cefazolin, Cefamandol und Cefazaflur hemmten einige dieser Stämme trotz der Zerstörung durch die -Lactamasen. Es wird postuliert, daß verschiedene Cephalosporine für die Empfindlichkeitstestung gram-negativer Bazillen erforderlich sind.

---

---

This work was supported by grants from the Lilly Research Laboratories and Smith Kline and French Laboratories.     

Distribution pattern of α and β myosin in normal and diseased human ventricular myocardium

Summary All fibers in three normal, four dilated, and two ischemic human ventricles were classified according to their myosin content using three sets of monoclonal antibodies each specific for one myosin heavy chain isoform (, and ). Numerous fibers contained only myosin heavy chain (denoted as fibers), others contained either and , or and myosin heavy chain (denoted as and fibers, respectively). The percentages of fibers were systematically determined along the walls of seven homologous regions of the ventricular myocardium.In all ventricles, there was an -fiber transmural gradient, with less fiber in the subendocardium than in the subepicardium. More fibers were found in the right than in the left ventricular wall but there was no difference between the mid-portion and the apex of the free wall of each ventricle. The diseased ventricles contained a lower fiber percentage than the normal hearts. fibers were very rare in the normal ventricles (less than 5%) and almost inexistent in pathological hearts. The correlation between the mean fiber percentages of the diseased hearts and their cardiac indices (r=0.88, P<0.05) suggests that the small amount of myosin distributed in a large number of ventricular fibers could play a role in the contractile performance of the heart. In conclusion, this study provides evidence for 1) an fiber transmural gradient, and 2) a lower myosin ratio in discased than in normal human ventricle.This work was supported in part by L'Institut National de la Santé et de la Recherche Médicale 101 rue de Tolbiac, 75013 Paris     

Rapid molecular characterization of mutations leading to unstable hemoglobin β-chain variants

Summary Characterization of unstable hemoglobins by protein analysis is often difficult. However, it is facilitated by DNA analysis, especially in the case of hyperunstable -chain variants, which produce a -thalassemia phenotype. We have applied an efficient strategy to the detection of such variants at the DNA level, based on computer-designed denaturing gradient gel electrophoresis (DGGE) of amplified DNA fragments. This approach makes it possible to detect any anomaly in the -globin gene. We describe the use of the DGGE method for rapid characterization of -chain variants and report a new missense mutation in the -globin gene third exon, 127 CAG-CGG/Gln-Arg, which is responsible for the synthesis of a highly unstable hemoglobin.     

Oligosaccharides accumulated in the bovineβ-mannosidosis kidney

Summary The phenotype of bovine-mannosidosis (-mannosidase deficiency), recently identified in Salers cattle, is similar to the caprine form of the disease (Abbittet al., 1991). This investigation was designed to characterize accumulated kidney oligosaccharides in bovine-mannosidosis. Oligosaccharides were extracted from the kidney of an affected Salers calf and purified by chromatographic techniques. The amount of accumulating oligosaccharides in 1 g of wet tissue was about 21µmol. Structures of derivatized oligosaccharides were characterized by high-performance liquid chromatography, mass spectrometry, methylation analysis and sequential exoglycosidase digestions. The major accumulating oligosaccharides were Man1-4GlcNAc and Man1-4GlcNAc1-4GlcNAc. Oligosaccharides accumulating in minor amounts were Man1-4GlcNAc1-4Man1-4GlcNAc, Man1-6Man1-4GlcNAc1-4GlcNAc and Man1-4GlcNAc1-4Man1-4GlcNAc1-4GlcNAc. As in caprine-mannosidosis, oligosaccharides with terminal-mannose residues and cleaved as well as uncleaved chitobiose linkages were identified in bovine-mannosidosis kidney. The accumulating oligosaccharides in tissue were thus identical in bovine and caprine-mannosidosis; however, the source of the novel oligosaccharides remains to be determined.     

Changes in the hydroxyproline,hexosamine and sialic acid of the diabetic human and β, β′-iminodipropionitrile-treated rat retinal vascular systems

Summary The retinal vasculature has been isolated from nondiabetic and diabetic post mortem human eyes by controlled trypsin digestion. Chemical analysis demonstrated increases in the hydroxyproline and hexosamine contents in diabetes. There was no general increase in the sialic acid content. These results have been related to histological preparations of sectors of the same retinas. Administration of, -iminodipropionitrile to rats caused a retinopathy characterised by endothelial cell proliferation, increased PAS-positivity and microaneurysms. Chemical analysis of retinal vascular systems from, -iminodipropionitrile-treated rats revealed increases in hydroxyproline, hexosamine and sialic acid contents.

---

Änderungen des Gehaltes an Hydroxyprolin, Hexosamin und N- azetyl- Neuraminsäure in den Netzhautgefäen von menschlichen Diabetikern und mit , Iminodiproprionitril behandelten Ratten

Zusammenfassung Die Netzhautgefäße wurden post-mortal aus diabetischen und nichtdiabetischen Augen mit Hilfe einer kontrollierten Trypsin-Behandlung gewonnen. Bei der chemischen Analyse fand sich ein Anstieg des Hydroxyprolin- und Hexosamingehaltes in den diabetischen Augen. Der N-azetyl-Neuraminsäuregehalt war im allgemeinen nicht erhöht. Diese Resultate wurden in Beziehung gebracht zu den histologischen Befunden, die an den einzelnen Sektoren der gleichen Retina erhoben wurden. Verabreichung von, -Iminodiproprionitril an Ratten bewirkte eine Retinopathie unter den Zeichen einer Wucherung der Endothelzellen, verstärkter PAS-Anfärbbarkeit und Mikroaneurysmen. Die chemische Analyse der Netzhautgefäße von mit, -Iminodiproprionitril behandelten Ratten zeigte einen erhöhten Gehalt an Hydroxyprolin, Hexosamin und N-azetyl-Neuraminsäure.

---

Variations de l'hydroxyproline, de l'hexosamine et de l'acide sialique dans les systèmes vasculaires rétiniens de l'homme diabétique et du rat traité par le , -iminodipropionitrile

Résumé Le système vasculaire rétinien a été isolé, par digestion trypsique contrôlée, après la mort, à partir d'yeux humains de non-diabétiques et de diabétiques. L'analyse chimique a révélé l'augmentation du contenu en hydroxyproline et en hexosamine, dans le diabète. Il n'y avait pas d'augmentation générale du contenu en acide sialique. Ces résultats ont été rapprochés des préparations histologiques de portions des mêmes rétines. L'administration de, -iminodipropionitrile à des rats provoquait une rétinopathie caractérisée par une prolifération des cellules endothéliales, une PAS-positivité augmentée et des microanévrismes. L'analyse chimique des systèmes vasculaires rétiniens des rats traités par le,-iminodipropionitrile, a révélé l'augmentation du contenu en hydroxyproline, en hexosamine et en acide sialique.

     

Thymosin β4 induced phenotypic changes in Molt-4 leukemic cell line

Summary Thymosin ₄ was tested for its ability to induce phenotypic changes in the human T-cell line Molt-4. Cells were cultured with nanogram concentrations of thymosin ₄ for up to 16 days and were analyzed with a panel of monoclonal antibodies, sheep erythrocyte rosetting, peanut agglutinin binding (PNA) and an antibody to the enzyme, terminal deoxynucleotidyl transferase (TdT). Thymosin ₄ induced Molt-4 cells to reduce the expression of a T-cell lineage specific antigen, with preferential expression on T blast-cells, detected by WT 1 monoclonal antibody. Thymosin ₄ also induced an increase in sheep erythrocyte rosettes and PNA binding as well as an increased expression of OKT 11A and OKT8 in Molt-4 cells. TdT was found to be unchanged, however. Analysis of thymosin ₄-treated cells with other monoclonal antibodies (OKT3, OKT6, OKT9) showed no change when compared to controls. These results showed that thymosin ₄ is capable of inducing phenotypic changes in Molt-4 cells. Such changes may represent a differentiation process of these cells through the early stages of the maturation process of thymus-dependent lymphocytes, albeit not to the stage of mature T cells.     

Inactivation of HIV in plasma derivatives by β-propiolactone and UV irradiation

Summary The inactivation of HIV in human plasma and plasma derivatives by combined treatment with -propiolactone and UV-irradiation was investigated. -propiolactone inactivated 3.5 log₁₀ and UV 2.8 log₁₀ HIV in plasma and -propiolactone 3.5 log₁₀ in cryoprecipitate and UV irradiation 4.5 log₁₀ in factor VIII concentrate.

---

Inaktivierung von HIV in Plasmaderivaten durch -Propiolacton in Kombination mit UV-Bestrahlung

Zusammenfassung Untersucht wurde die Inaktivierung von HIV in humanem Plasma und Plasmaderivaten durch die kombinierte Behandlung mit -Propiolacton und UV-Bestrahlung. HIV wurde durch -Propiolacton um 3,5 log₁₀ und UV um 2,8 log₁₀ in Plasma und durch -Propiolacton um 3,5 log₁₀ in Kryopräzipitat bzw. durch UV um 4,5 log₁₀ in Faktor VIII-Konzentrat inaktiviert.

     

Functional and morphological effects of interleukin-1β on the perfused rat pancreas

Summary We recently reported a potentiating effect of recombinant human interleukin-1 on glucose-stimulated insulin release from the isolated perfused pancreas. With the aim of determining whether the stimulatory effect of recombinant interleukin-1 on the B cell in the intact gland was modulated by varying the concentration, time of exposure to recombinant interleukin-1 or B-cell activity, and to elucidate a possible mechanism of action, we measured in the perfused rat pancreas the release of insulin, glucagon and/or prostaglandin E₂ according to the following three different protocols: (1) perfusion with 20 ng/ml of recombinant interleukin-1 for 92 min at 5 and 20 mmol/1 D-glucose (2) perfusion with varying concentrations of recombinant interleukin-1 ranging from 0.1×10^–3 ng/ml to 100 ng/ml at 5 and 20 mmol/l D-glucose (3) perfusion with 20 ng/ml of recombinant interleukin-1 at 5,11 or 20 mmol/l D-glucose. Furthermore, in a separate set of experiments we examined the influence of the cytokine on the morphology of the endocrine pancreas. Interleukin-1 stimulated insulin secretion at 11 and 20 mmol/l D-glucose and potentiated first as well as second phase insulin release in a dose-dependent fashion, with decreasing effect at higher concentrations. Glucagon secretion was also stimulated by recombinant interleukin-1, irrespective of increasing glucose (5, 11, 20 mmol/l) and insulin concentrations. The potentiating effect of recombinant interleukin-1 on insulin secretion was evident even after discontinued perfusion with the cytokine, suggesting a priming effect on B-cell function. Furthermore, we did not observe any relation between the recombinant interleukin-1 mediated insulin and glucagon release and prostaglandin E₂. Electron microscopy of the pancreata perfused with recombinant interleukin-1 revealed significant B cell and to a lesser extent A-cell lysis as well as induction of cell protrusions (blebs) in B cells only, accompanied by peripheral degranulation and rearrangement of rough endoplasmatic reticulum. We suggest that in addition to a paracrine effect of locally produced interleukin-1 systemic interleukin-1 may have an endocrine effect on A- and B-cell function and viability. Interleukin-1 should be considered to be a physiological modulator of insulin and glucagon secretion e.g. during the acute phase response, but also as a pathogenetic factor in Type 1 (insulin-dependent) diabetes mellitus.