Hepatitis B and circadian rhythm of the liver

The circadian rhythm in humans is determined by the central clock located in the hypothalamus’s suprachiasmatic nucleus, and it synchronizes the peripheral clocks in other tissues. Circadian clock genes and clock-controlled genes exist in almost all cell types. They have an essential role in many physiological processes, including lipid metabolism in the liver, regulation of the immune system, and the severity of infections. In addition, circadian rhythm genes can stimulate the immune response of host cells to virus infection. Hepatitis B virus (HBV) infection is the leading cause of liver disease and liver cancer globally. HBV infection depends on the host cell, and hepatocyte circadian rhythm genes are associated with HBV replication, survival, and spread. The core circadian rhythm proteins, REV-ERB and brain and muscle ARNTL-like protein 1, have a crucial role in HBV replication in hepatocytes. In addition to influencing the virus’s life cycle, the circadian rhythm also affects the pharmacokinetics and efficacy of antiviral vaccines. Therefore, it is vital to apply antiviral therapy at the appropriate time of day to reduce toxicity and improve the effectiveness of antiviral treatment. For these reasons, understanding the role of the circadian rhythm in the regulation of HBV infection and host responses to the virus provides us with a new perspective of the interplay of the circadian rhythm and anti-HBV therapy. Therefore, this review emphasizes the importance of the circadian rhythm in HBV infection and the optimization of antiviral treatment based on the circadian rhythm-dependent immune response.     

The effect of soluflazine on sleep in rats

Soluflazine, a specific adenosine transport inhibitor, was intracerebroventricularly administered to rats in a dose range of 10, 25, and 50 nmoles. At a dose of 50 nmoles, soluflazine decreased waking and increased sleep during the first hour of EEG recording. Our previous work has shown that chronic intracerebroventricular administration of soluflazine to rats decreased radioligand binding to adenosine A1 and A2 receptors in specific brain regions. The present data show that administration of an adenosine transport inhibitor to rats produces a transient hypnotic effect presumably through increases in synaptic adenosine levels.     

Protective effect of interferon-α on the DNA- and RNA-degrading pathway in anti-Fas-antibody induced apoptosis

Aim: Fas membrane-associated polypeptide antigen is a receptor molecule responsible for apoptosis-mediated signals. In animal models of acute viral hepatitis, apoptosis of hepatocytes is mediated by Fas-death receptors; therefore, the aim of this study was to evaluate the effect of interferon (IFN)-alpha on apoptotic markers and nuclease activity against different coding and non-coding single and double stranded RNAs during Fas-induced liver apoptosis. Methods: An in vivo experiment was performed with simultaneous administration of anti-Fas (CD95) antibodies and IFN-alpha, and an in vitro experiment was performed in hepatocyte cultures treated with anti-Fas antibodies and IFN-alpha. Results: Detection of apoptosis using Annexin V-FITC/propidium iodide, Bcl-2 and Bax expression in hepatocyte cultures confirmed the appearance of early apoptotic events and progression toward late apoptosis after anti-Fas antibody treatment. IFN-alpha had a tendency to retard the apoptosis process in Fas-induced apoptosis by increasing the number of viable cells and decreasing the number of cells in late apoptosis, by increasing the percentage of Bcl-2 positive cells, by decreasing the percentage of Bax positive cells, and by decreasing the nuclease activity compared to the anti-Fas antibody treated group. Total DNA and RNA concentration was much reduced in the Fas group and DNA fragmentation assay provided evidence for increased DNA degradation. Enhanced nuclease activity against DNA, rRNA, poly(A), poly(C), poly(U), poly(I:C), and poly(A:U) was manifested in the anti-Fas antibody treated group, except for the inhibitory-bound alkaline RNase. Conclusions: The results demonstrate that the RNA-degrading pathway in Fas-induced apoptosis can accelerate the liberation of the latent enzyme from the inhibitor complex. IFN-alpha prevented enormous, Fas-ligand induced degradation of all the substrates used in this experimental study, most probably due to similarities in the signal transduction pathways. Investigations of death receptor-induced apoptosis may lead to novel treatment combinations for patients with acute or chronic liver diseases.     

Chronic peritoneal dialysis in paediatrics: Experience of a national registry

The results of the first 3 year' collaboration of the Italian Registry of Paediatric Chronic Peritoneal Dialysis (CPD) (1986–1988) are presented. This Registry acquired data on the majority of the paediatric patients treated with CPD in Italy, thus providing a national picture in a field where few nationwide surveys are available. Patients of less than 15 years of age at the start of dialysis were enrolled and clinical data collected until the age of 19 years. The number of nephrological paediatric centres participating in the Registry increased from 7 in 1986 to 11 in 1988. The total number of patients on CPD was 70 and the percentage of dialysed children treated with CPD ranged from 40.2% to 43.6%. Data on 89 peritoneal catheters were collected: during 1417 dialysis-months 70 catheter-related complications were observed (1:20.8 dialysis-months); actuarial catheter survival was 92.7% at 6 months, 84.8% at 1 year and 68.8% at 2 years. The incidence of peritonitis changed from 1 episode every 10.9 patient-months in 1986 to 1 every 19.8 in 1988. Abdominal hernias were the other main clinical complication observed. The survival of patients was 92.5% at 3 years, while the technique survival at the same time was 84%.     

Degenerative neurological disorders associated with deficiency of glutamate dehydrogenase

Summary The activity of glutamate dehydrogenase, the enzyme of glutamate degradation, was measured in platelets of 27 healthy controls and 85 patients with different degenerative cerebellar and/or basal ganglia disorders. A group of 7 patients was selected with slowly progressive multiple-system atrophy, in whom a clinical diagnosis of olivopontocerebellar atrophy appeared tenable, with decreased activity of glutamate dehydrogenase (38% of the mean control value). In 4 patients data on inheritance were compatible with the genetic pattern of autosomal recessive inheritance, while 3 patients were sporadic cases. In an effort to define this group of patients more precisely, it is suggested that decreased activity of glutamate dehydrogenase induces an increase in extracellular glutamate levels in the central nervous system with subsequent development of excitotoxicity.     

Increased in vivo frequency of IA-2 peptide-reactive IFNgamma+/IL-4- T cells in type 1 diabetic subjects

Active T cell recognition of islet antigens has been postulated as the pathogenic mechanism in human type 1 diabetes, but evidence is scarce. If T cells are engaged, they are expected to display increased clonal size and exhibit a T helper (Th)1/Th2 differentiation state. We used a peptide library that covers tyrosine phosphatase IA-2, a target antigen expressed in pancreatic beta cells, to probe 8 diabetic patients and 5 HLA-matched controls. When tested in a high resolution IFNgamma/IL-4 double color ELISPOT assay directly ex vivo, the number of IA-2-reactive IFNgamma producing cells was 17-fold higher in patients than in controls and IL-4 producing cells were not present. An average of 9 peptides was recognized in the patients vs. one in the controls. Determinant recognition primarily involved CD4+ cells and showed high variability among the patients. Furthermore, anti-CD28 antibody signal enhances quantitative assessment of effector T cells in T1D patients. In vitro expansion with peptides and IL-2 results in detection of responding cells in the controls and loss of disease specificity of the T cell response. Together these data provide strong evidence for the active targeting of IA-2 by Th1 memory effector cells in human type 1 diabetes.     

Identification and characterization of clinical isolates of members of the Staphylococcus sciuri group

A total of 28 staphylococcal isolates from human clinical specimens belonging to the Staphylococcus sciuri group were identified and characterized. The API Staph and ID32 STAPH correctly identified S. sciuri and S. lentus but not S. vitulinus strains. Identification to the subspecies level was possible only by a PCR-based method.     

T Cells Recognize Multiple GAD65 and Proinsulin Epitopes in Human Type 1 Diabetes, Suggesting Determinant Spreading

Human type 1 diabetes is thought to be mediated by autoreactive T cells specific for antigens expressed by pancreatic beta cells. However, it is unclear which autoantigens and determinants thereof are the targets of the autoimmune attack. Using comprehensive peptide libraries that cover the entire sequence of two major candidate autoantigens, GAD65 and proinsulin, we measured the in vivo frequencies of peptide-specific, IFN-gamma-producing memory T cells in 27 diabetic patients, 14 high risk individuals, and 15 partially HLA-matched healthy controls. Compared to the controls, both a higher number of determinants on the islet cell antigens were recognized and the frequencies of peptide specific cells were increased in patients and high risk individuals. Inclusion of signal enhancing anti-CD28 antibody further accentuated this difference. Considerable heterogeneity in peptide recognition was seen even in DRB1*04, DQB1*0302 matched individuals. Unlike its peptides, the GAD protein antigen did not recall a T cell memory response. The highly heterogeneous recognition of a multitude of peptide determinants on both autoantigens, occurring in the absence of protein recognition, and the low functional avidity of the memory cells involved jointly suggest that the autoimmune T cell repertoire in human type 1 diabetes primarily targets cryptic determinants engaged by determinant spreading.     

Isolation of members of the Staphylococcus sciuri group from urine and their relationship to urinary tract infections

During a 3-year study period, 32,741 urine samples were analyzed for the presence of members of the Staphylococcus sciuri group (S. sciuri, S. lentus, and S. vitulinus), and 13 isolates were identified. They presented 0.79% of the total number of coagulase-negative staphylococci isolated. One case of symptomatic urinary tract infection and five possible cases of asymptomatic bacteriuria caused by these bacteria were established. It is noteworthy, however, that over 50% of the isolates originated from hospitalized patients.