Aminoguanidine downregulates expression of cytokine-induced Fas and inducible nitric oxide synthase but not cytokine-enhanced surface antigens of rat islet cells

Autoimmune beta-cell destruction occurs directly by cell-mediated cytotoxicity or indirectly by cytokines released from infiltrating lymphocytes. Cytokines (IL-1beta/IFN-gamma) modify or induce expression of MHC antigens and ICAM-1 on beta-cells which can lead to an improved binding of T-lymphocytes to beta-cells and finally to an enhanced cell-mediated cytotoxicity. Cytokines also induce Fas-expression and inducible nitric oxide synthase (iNOS) causing generation of nitric oxide (NO) which is toxic for beta-cells. The iNOS inhibitor aminoguanidine (AG) delays diabetes onset, but does not reduce diabetes incidence. We wanted to know whether AG inhibits cytokine-induced expression of Fas, MHC antigens and ICAM-1 on beta-cells of LEW.1W and BB/OK rat islets after culture with IL-1beta/IFN-gamma. NO was completely inhibited by 5.0 mmol/L AG while 0.5 mmol/L had no inhibitory effect. AG downregulated Fas-expression on the surface of beta-cells. Cytokine-induced/enhanced expression of MHC class-II and ICAM-1 was not affected by any AG concentration. AG syngergistically increased cytokine-induced enhancement of MHC class-I antigen density. AG possibly blocks the indirect pathway of beta-cell damage in vivo due to inhibition of Fas and iNOS and improves direct cell-mediated cytotoxicity due to drastic increased MHC class-I expression. Inhibition of only one pathway of beta-cell destruction is not sufficient to prevent diabetes.     

Evaluation of mammographic and clinical follow-up after 755 stereotactic vacuum-assisted breast biopsies

PURPOSE: Stereotactic vacuum-assisted breast biopsy (VB) is a new method that promises high accuracy and reliability. In order to avoid surgery in cases with benign histology the examination must be quality assured and the accuracy should be well established. We present follow-up data of 755 VBs with benign results. METHODS: In all, 984 of 1268 consecutive VBs proved histopathologically benign (lobular carcinoma in situ and atypical ductal hyperplasia not included). Follow-up data are available for 755 of 984 (77%) lesions and constitute the basis of this evaluation. Follow-up mammograms were performed of 728 lesions at 6 to 67 months (mean 24, median 17.8) after VB. RESULTS: Seven technically unsuccessful cases underwent immediate rebiopsy; 3 unsuccessful cases were diagnosed otherwise. No false negative occurred among the 752 followed-up, eventually successful VBs. On follow-up mammography 444 of 728 (61%) benign lesions proved radiologically completely removed, 284 (39%) partially. In 6 cases (0.8%) a surgical biopsy was performed again during the follow-up time confirming the benign result. No scar was seen in 96%, a slight scar in 3.8%, and a small stellate scar with possible diagnostic interference in 0.3%. CONCLUSIONS: A benign diagnosis of quality assured VB is very reliable and leads to no or minimal scarring.     

Synthesis and 5-HT2A radioligand receptor binding assays of DOMCl and DOMOM,two novel 5-HT2A receptor ligands

A synthesis of two new active substances, DOMCl (1-(4-chloromethyl-2, 5-dimethoxyphenyl)-2-propanamine; 2) and DOMOM (1-(2, 5-dimethoxy-4-methoxymethylphenyl)-2-propanamine; 3), was developed. Unexpectedly, the Blanc reaction permitted successful synthesis of 2, 5-dimethoxyphenylpropylamine derivatives having a substituted methyl group in position 4 since solvation of the reactant occurs during the reaction. Afterwards, their affinities towards the 5-HT(2A) receptor were examined in 5-HT(2A) radioligand receptor binding assays. The study of these substances is of considerable interest because they were predicted, by preliminary molecular modeling studies based on mescalin units, to be potential new hallucinogens that should be added to the list of substances prohibited by law. It was assumed that DOMCl would be 82 times more potent as a hallucinogen than mescalin, and DOMOM would be 94 times more potent. The 5-HT(2A) radioligand receptor binding studies showed that the affinities of DOMCl and DOMOM for the 5-HT(2A) receptor are less than expected but are nevertheless 1.6 and 8.7 times higher, respectively, than that of mescalin. Therefore, scheduling these substances as potential drugs of abuse might be considered.     

Daytime predictors of sleep disordered breathing in children and adolescents with neuromuscular disorders

Sleep disordered breathing with or without nocturnal hypercapnic hypoventilation is a common complication of respiratory muscle weakness in childhood neuromuscular disorders. Nocturnal hypercapnic hypoventilation as a sign of respiratory muscle fatigue, portends a particularly poor prognosis. We aimed at identifying daytime predictors of sleep disordered breathing at its onset and sleep disordered breathing with nocturnal hypercapnic hypoventilation. Forty-nine children and adolescents (11.3+/-4.4 years) with progressive neuromuscular disorders were studied with inspiratory vital capacity, peak inspiratory pressure, arterial blood gases, polysomnography, and a ten-item symptoms questionnaire. Daytime respiratory function was prospectively compared with polysomnographic variables. Sleep disordered breathing was found in 35/49 patients (71%). Twenty-four (49%) had sleep disordered breathing with nocturnal hypercapnic hypoventilation. Inspiratory vital capacity and peak inspiratory pressure, but not symptom score, correlated with sleep disordered breathing and severity of nocturnal hypercapnic hypoventilation. Sleep disordered breathing-onset was predicted by inspiratory vital capacity<60% (sens. 97%, spec. 87%). Sleep disordered breathing with nocturnal hypercapnic hypoventilation was predicted by inspiratory vital capacity<40% (sens. 96%, spec. 88%) and PaCO(2)>40 mmHg (sens. 92%, spec. 72%,). Sleep disordered breathing can reliably be predicted from simple daytime respiratory function tests, which, if applied systematically, will improve recognition of nocturnal respiratory failure.     

Homozygous mutations in caveolin-3 cause a severe form of rippling muscle disease

Heterozygous missense mutations in the caveolin-3 gene (CAV3) cause different muscle disorders. Most patients with CAV3 alterations present with rippling muscle disease (RMD) characterized by signs of increased muscle irritability without muscle weakness. In some patients, CAV3 mutations underlie the progressive limb-girdle muscular dystrophy type 1C (LGMD1C). Here, we report two unrelated patients with novel homozygous mutations (L86P and A92T) in CAV3. Both presented with a more severe clinical phenotype than usually seen in RMD. Immunohistochemical and immunoblot analyses of muscle biopsies showed a strong reduction of caveolin-3 in both homozygous RMD patients similar to the findings in heterozygous RMD. Electron microscopy studies showed a nearly complete absence of caveolae in the sarcolemma in all RMD patients analyzed. Additional plasma membrane irregularities (small plasmalemmal discontinuities, subsarcolemmal vacuoles, abnormal papillary projections) were more pronounced in homozygous than in heterozygous RMD patients. A stronger activation of nitric oxide synthase was observed in both homozygous patients compared with heterozygous RMD. Like in LGMD1C, dysferlin immunoreactivity is reduced in RMD but more pronounced in homozygous as compared with heterozygous RMD. Thus, we further extend the phenotypic variability of muscle caveolinopathies by identification of a severe form of RMD associated with homozygous CAV3 mutations.     

Enzymatic diagnostic test for Muscle-Eye-Brain type congenital muscular dystrophy using commercially available reagents

OBJECTIVES: Mutations disrupting the interaction of extra-cellular ligands and alpha-dystroglycan are responsible for an etiologically heterogeneous group of autosomal recessive congenital muscular dystrophies (CMD) that can have associated brain and eye abnormalities. The objective is to develop a diagnostic test for one of these CMDs, Muscle-Eye-Brain disease (MEB), due to mutations in the gene encoding Protein O-Mannosyl beta-1,2-N-acetylglucosaminyltransferase 1 (POMGnT1). DESIGN AND METHODS: POMGnT1 enzyme activity was determined in extracts of muscle biopsies from four MEB patients and various controls using commercially available reagents. RESULTS: All four MEB muscle samples showed a highly significant decrease in POMGnT1 activity relative to controls. CONCLUSIONS: The assay of POMGnT1 activity in MEB muscle provides a rapid and relatively simple diagnostic test for this disease. CMDs associated with brain malformations such as MEB, WWS and FCMD are heterogenous in clinical presentation and on radiologic examination, suggesting that POMGnT1 assays of muscle biopsies should be used as a screening procedure for MEB in all CMD patients associated with brain malformations.     

Die progressive multifokale Leukoenzephalopathie

Zusammenfassung □ Pathogenese  Die progressive multifokale Leukoenzephalopathie ist eine Entmarkungserkrankung des Zentralnervensystems, die durch eine Reaktivierung des JC-Virus hervorgerufen wird und bei etwa 5% aller Patienten mit HIV-Infektion auftritt. Nach den gegenw?rtigen Vorstellungen zur Pathogenese der progressiven multifokalen Leukoenzephalopathie handelt es sich um eine persistierende Infektion, die im Rhamen einer Abschw?chung der zellul?ren Immunit?t bei der HIV-Infektion reaktiviert wird. Als m?gliche Persistenzorte kommen Niere, Knochenmark, Lymphozyten oder das Zentralnervensystem selbst in Betracht. □ Diagnose  Die Diagnose einer progressiven multifokalen Leukoenzephalopathie wird durch das klinische Bild, das durch variable neurologische Herdsymptome gekennzeichnet ist, die Kernspintomographie des Gehirns und den Virusnachweis im Liquor gestellt. □ Therapie  Eine gesicherte erregerspezifische Therapie ist derzeit nicht m?glich. Mit der hochaktiven antiretroviralen Kombinationstherapie oder Cidofovir ergeben sich m?glicherweise neue therapeutische Optionen.      

Use of 1-Methyl-Pyrrolidone as a Solubilizing Agent for Determining the Uptake of Poorly Soluble Drugs

Pharmaceutical Research -