Non-alcoholic steatohepatitis induces non-fibrosis-related portal hypertension associated with splanchnic vasodilation and signs of a hyperdynamic circulation in vitro and in vivo in a rat model

INTRODUCTION

Steatosis, without fibrosis, may lead to changes in liver blood flow, which are poorly understood, and to date have not been correlated to portal pressure and related haemodynamics.

AIMS

To study the temporal relation between progressive steatosis, portal pressure, systemic haemodynamics, vascular responsiveness, mesenteric and portal blood flow in methionine-choline-deficient diet (MCDD)-fed rats.

METHODS

Male Wistar rats fed the MCDD were examined at week (w) 0-1-2-3-4-5-6-7-8, respectively, including systemic haemodynamics and portal pressure. At w0-4-8, in vivo blood flow was measured in the portal vein and the superior mesenteric artery. Dose-response curves to phenylephrine (PE) were established in abdominal aortic rings.

RESULTS

Histology showed 100% steatosis from w3 on. Fibrosis was absent. Significant inflammation was nearly absent upon w4. Portal pressure slightly increased at w2, reached a maximum at w4 [9.4 +/- 0.3 vs 2.9 +/- 0.6 mmHg at w0 (P=0.003)] and remained stable upon w8. Mean arterial blood pressure (MABP) decreased from w2 on [98.7 +/- 5.7 mmHg on w4 compared with 123.8 +/- 1.8 on w0 (P=0.002)]. Portal flow increased from 1.85 +/- 0.11 to 3.07 +/- 0.44 ml/min/100 g on w0 and w8 respectively (P=0.039). Mesenteric artery flow increased from 3.40 +/- 0.26 to 4.56 +/- 0.30 ml/min/100 g on w0 and w8 respectively (P=0.043). Vascular responsiveness to PE gradually decreased from 138 +/- 3% on w0 to 110 +/- 5% on w4 (P=0.013).

CONCLUSION

Steatohepatitis induces significant portal hypertension (PHT) in the absence of fibrosis, associated with an increase in mesenteric arterial and portal venous flow, arterial hyporesponsiveness to vasoconstrictors and a decrease in MABP, indicating the presence of splanchnic vasodilation and hyperdynamic circulation. These alterations resemble those seen in cirrhotic PHT.

Spontaneous second-site suppressors of the filamentation defect of prr1Delta mutants define a critical domain of Rim101p in Candida albicans

In response to changes in ambient pH the opportunistic pathogen Candida albicans differentially expresses a number of genes. The response to pH affects morphological differentiation and virulence. The pathway controlling the pH response terminates in the zinc-finger containing transcription factor encoded by RIM101/PRR2. By analogy to the pH response pathway of Aspergillus nidulans, PRR1 of C. albicans encodes a protein that is presumably required to convert Rim101p from an inactive to an active form by proteolytic removal of a C-terminal peptide. A prr1Delta mutant is compromised in its ability to differentiate into the filamentous form. Spontaneous phenotypic revertants of a prr1Delta mutant were selected by their ability to form filamentous colonies. These mutants were also found to be defective in pH-dependent gene expression. Each of the eight mutants examined contained a heterozygous dominant mutation at the RIM101 locus. This was demonstrated genetically in all of the mutants, and directly by sequence determination of both alleles in two of the mutants. The mutant alleles conferred the ability to filament to a prr1Delta mutant, thus demonstrating that they were directly responsible for suppressing the filamentation defect. Seven of the mutant alleles contained a 1-bp substitution and one contained two substitutions at adjacent positions. The mutations were clustered within a 90-bp region near the 3'-end of the gene. In all cases the mutation generated a nonsense codon that resulted in premature termination of Rim101p; the mutant proteins were truncated by 75-104 amino acids. The results define a critical region in the C-terminal region of Rim101p and are consistent with the proposed proteolytic activation of Rim101p.

Dynamics of active progressive infection with HIV1: data acquisition for computer modeling

Nineteen adult patients with progressive HIV1 infection, which progressed within 5 years from acute HIV syndrome to final AIDS were studied. Changes in HIV antibody titer, viral RNA load, peripheral T lymphocytes and subpopulations as well as CD4/CD8 cell ratio and cell death (apoptosis) were monitored. The data were collected for comparison with HHV-6 infection, which involves the same cell populations yet patients usually recover, and to serve as a further basis for future computer simulation studies. The results showed progressive increases of viral RNA copies in the patients' plasma even during clinical latency, which correlates with lymphocyte apoptosis and CD4 cell loss. Besides apparent direct CD4 cell destruction, there was indication of a disturbed intrathymic T cell differentiation. Pathologic cell changes in HIV infection continue until final death of the patient and do not return to normal after variable times as in HHV-6 infection. While HHV-6 infection can serve as models for immunostimulation, with or without immune dysregulation in computer simulation studies, HIV infection is a model for immunostimulation with final immune deficiency and cellular aplasia.

In vitro selection of resistance to clindamycin related to alterations in the attenuator of the erm(TR) gene of Streptococcus pyogenes UCN1 inducibly resistant to erythromycin

A clinical isolate of Streptococcus pyogenes UCN1 intermediate to erythromycin (MIC 1 mg/L) and susceptible to clindamycin (MIC 0.03 mg/L) harboured an inducible erm(TR) gene encoding a ribosomal methylase. We have selected in vitro, in the presence of concentrations of clindamycin ranging from 0.12 to 1 mg/L, one-step mutants that are highly resistant to this antibiotic (MIC 64 mg/L) at a frequency of 10(-7). By contrast, in an erythromycin-susceptible strain of S. pyogenes UCN5, mutants could be selected only by a low concentration of clindamycin (0.12 mg/L) at a frequency of 10(-9). Clindamycin resistance in four of six S. pyogenes UCN1 mutants was associated with deletions of 163 and 6 bp, as well as a tandem duplication of 101 bp in the regulatory sequence of the erm(TR) gene. The role of these structural alterations in clindamycin resistance was demonstrated by cloning the erm(TR) gene from the wild-type and mutant strains in Escherichia coli DB10, a mutant susceptible to macrolides. Clindamycin resistance was expressed only when the erm(TR) gene was preceded by an altered attenuator. Mutations could lead to the formation of mRNA secondary structures accounting for the accessibility of the ribosome-binding site and the initiation codon of the ErmTR methylase to the ribosomes, and subsequently for the translation of the erm(TR) transcripts. The easy selection in one step of mutants resistant to high levels of clindamycin by concentrations of this antibiotic ranging from four to 40 times the MIC leads us to recommend caution in the use of clindamycin therapy in group A Streptococcus infections.

Dynamics of infection with human herpesvirus-6 in EBV-negative infectious mononucleosis: data acquisition for computer modeling

Ten adult patients with active HHV-6 variant A infections and clinical infectious mononucleosis-like disease (IM) were studied over a period of 32 weeks after onset of disease for their viral DNA load, changes in peripheral blood T-lymphocytes and subpopulations and frequency of cell death in peripheral blood cells. The data were collected as the basis for an advanced computer simulation study for which available data in the literature were too varied. Since the exact time of primary infection of the patients was not known and thus no time relationship of viral effects at cellular level were determined, we supplemented such data from separate tissue culture studies using HHV-6 alpha infection of HSB2 cells. Patients with IM demonstrate an increase in-HHV-6 DNA copies from 0 to 8.2 log 10/5 microL blood within 4 weeks return to normal by 16 weeks. Total T-lymphocytes follow infection with a 20-fold increase above normal peaking at 8-10 weeks and then return to normal by 24-28 weeks. Coincidently, less mature lymphoid cells carrying markers for stem cells, thymic cortical and medullary cells increase 8-10-fold indicating an enhanced mobilization of such cells from premature cell compartments. Cell death in peripheral mononuclear cells peaked with 30% at 8 weeks after onset of clinical disease and normalized by 24 weeks. HHV-6 replication in cell culture as determined by antigen expression, electron microscopy and harvest of infectious virus indicated a complete cycle of virus infection and replication of at least 6 days. The presented data compare well with others from the literature and will serve for testing in a computer simulation model, which is the subject of a forthcoming paper.

Dominant active alleles of RIM101 (PRR2) bypass the pH restriction on filamentation of Candida albicans

Morphological development of the fungal pathogen Candida albicans is profoundly affected by ambient pH. Acidic pH restricts growth to the yeast form, whereas neutral pH permits development of the filamentous form. Superimposed on the pH restriction is a temperature requirement of approximately 37 degrees C for filamentation. The role of pH in development was investigated by selecting revertants of phr2Delta mutants that had gained the ability to grow at acid pH. The extragenic suppressors in two independent revertants were identified as nonsense mutations in the pH response regulator RIM101 (PRR2) that resulted in a carboxy-terminal truncation of the open reading frame. These dominant active alleles conferred the ability to filament at acidic pH, to express PHR1, an alkaline-expressed gene, at acidic pH, and to repress the acid-expressed gene PHR2. It was also observed that both the wild-type and mutant alleles could act as multicopy suppressors of the temperature restriction on filamentation, allowing extensive filamentation at 29 degrees C. The ability of the activated alleles to promote filamentation was dependent upon the developmental regulator EFG1. The results suggest that RIM101 is responsible for the pH dependence of hyphal development.

HBV-specific lymphoproliferative and cytokine responses in patients with chronic hepatitis B

BACKGROUND/AIMS

Hepatitis B virus specific T cell responses are crucial for viral elimination but their nature is not fully understood.

METHODS

We studied the regulation of proliferation and cytokine production after antigenic stimulation in peripheral blood mononuclear cells from chronically HBV-infected patients and subjects with natural immunity after recovery from an acute infection. Proliferation and production of interferon-gamma, IL-10 and tumor necrosis factor-alpha were determined after stimulation with HBcAg, HBeAg or HBsAg in the absence or presence of IL-12 or neutralizing antibodies to IL-12, interferon-gamma, IL-4, IL-10 or tumor necrosis factor-alpha.

RESULTS

Upon stimulation with HBcAg or HBeAg, peripheral blood mononuclear cells from chronic hepatitis B virus patients displayed a clear class-II restricted proliferative response (SI greater than 2.5). Both interferon-gamma (less than 50 IU/ml) and IL-10 levels up to 600 pg/ml were detected. Proliferative or cytokine responses to HBsAg were very weak or absent. Addition of IL-12 to HBeAg-stimulated cultures increased the production of interferon-gamma to more than 200 IU/ml in all patients and slightly increased the production of IL-10. Neutralization of IL-10 increased the HBeAg-induced interferon-gamma production but had no effect on tumor necrosis factor-alpha production. Addition of anti-IL-4 or anti-tumor necrosis factor-alpha had no significant influence on proliferation or cytokine release. Importantly, in both chronic hepatitis B virus patients and naturally immune subjects, IL-12 induced proliferative and interferon-gamma responses in peripheral blood mononuclear cells stimulated with HBsAg.

CONCLUSIONS

Our data indicate that peripheral blood mononuclear cells from chronic hepatitis B virus patients proliferate and produce interferon-gamma and IL-10 upon HBeAg but not upon HBsAg stimulation. IL-12 augments the HBeAg-induced responses and, additionally, provokes proliferation and interferon-gamma production in HBsAg-stimulated cultures.

[Seroprevalence of HCV in the general population of Niger and in patients with chronic liver diseases: comparison of different second generation tests and PCR]

The aim of our study in Niger was to compare the seroprevalence of hepatitis C in a rural "normal" population and in a group of patients presenting at the hospital with signs of chronic liver disease: to estimate this seroprevalence, we used 4 second generation ELISA screening and 3 confirmatory tests (LIA, RIBA and PCR); genotyping was performed on PCR positive sera, using Inno-LIPA HCV. We could not find a statistically significant difference (Fisher's exact test) between the two groups of healthy and sick people (2.5 versus 5.4% for seroprevalence and 2.5 versus 3.2% for viremia). Our study didn't find any relationship between hepatitis C infection, blood transfusion or surgery; other major ways of transmission of hepatitis C have to be considered. The predominant genotype detected was 2a.

Demonstration of active and latent Epstein-Barr virus and human herpevirus-6 infections in bone marrow cells of patients with myelodysplasia and chronic myeloproliferative diseases

After previous serological screening for Epstein-Barr virus (EBV), human herpesvirus-6 (HHV-6) and human cytomegalovirus (HCMV) showed elevated antibody titers against EBV and HHV-6 in more than 50% of patients with myelodysplasia and chronic myeloproliferative diseases, the present study was carried out in order to investigate viral antigen expression and distribution in bone marrow cells of these patients. Trephine biopsies were studied from 60 patients with myelodysplasia (MDS), 36 patients with chronic myelogenous leukemia (CML) and 18 patients with osteomyelofibrosis (PMF). Elevated anti-EBV EA titers were found in 62% of the MDS cases, in 33% of the CMLs and in 62% of the OMF patients. HHV-6 titers were elevated in 18% of the MDS cases, but in only one case each of CML and OMF. Antigen expression in bone marrow cells was even more frequent: EBV-EA was 76% in MDS cases, 77% in CML and 40% in OMF. HHV-6 p41 was observed in 47% of the MDS cases, in 54% of the CML cases and in 20% of the OMFs. In comparing these data with those from the literature and with our own studies in Hodgkin's disease, it is hypothesized that the reactivated herpesviruses may contribute to the pathogenesis of these hematopoietic disorders by interfering with the cytokine regulation of cell proliferation and differentiation.

Lyme disease in Belgium

A sero-epidemiological clinical and risk-group study was performed in Belgian Military men with a home-made Elisa kit, with the N34 Bb strain kindly provided by Prof. Ackermann Cologne. In the sero-epidemiological group the seroprevalence (age 18-28 years) was 3.2% In the clinical group the results were correlating to the serological and clinical data. In the risk group 44% were IgG positive. In conclusion the exposure of a standard Belgian young male population is low. (Overall IgG seropositivity 3.2%) (Total N = 1,916).

Rapid, sensitive micro blood lead analysis: a mass screening technique for lead poisoning

A rapid micro blood lead method is described. Analyses were performed on 20-microL blood samples spotted on filter paper, collected in graduated heparinized capillary glass tubes following finger pricks. The samples were air dried on filter paper and mailed to the laboratory in glassine envelopes. These samples stored on filter paper are stable for at least six months. The blood spots were punched out with a 1/4-in. diameter hole punch and placed in Delves cups for insertion into the flame atomic absorption spectrometer. The innovation of this method is that an ashing step precedes sample introduction into the flame. In phase 1, the Delves cup with the blood sample is pushed 1 cm from the flame. The heat is sufficient for the filter paper to ignite and burn to completion in seconds. After the smoke dissipates, the samples are introduced into the flame for lead analysis, reading the signal at 283.3 nm. The entire analysis time is 15 s per sample. The limit of quantitation is 4 micrograms/dL of lead. Standard curves were linear from 4-42 micrograms/dL. The average CV for this range is 8.2%. The comparative study between the MIBK extraction method and this method yielded a correlation coefficient r = .99 (n = 55). The method is fast, practical, economical, and easily adaptable to screen large numbers of micro lead samples.

Postinfectious chronic fatigue syndrome: case history of thirty-five patients in Germany

Thirty-five patients with chronic fatigue syndrome according to the criteria of Holmes were followed for periods of up to eight years. The most frequent symptoms were severe fatigue, arthralgias and myalgias, recurrent oropharyngitis and various psychiatric disorders. More than half of the patients suffered from neuropathy, lymphadenopathy, gastrointestinal complaints and recurrent low-grade fever. Recurrent or persistent activity of human herpesvirus -6 infection was seen in 73% of the patients and of Epstein-Barr virus in 34.4%. In addition, various other infections were diagnosed at lower frequency. Initial routine immunologic screening revealed various types of deficiencies, these were yet inconsistent and variable when different patients were compared with each other. Tentative treatments included in immunoglobulins, nonspecific immunostimulation and virostatic drugs. No consistently positive results were obtained with any treatment schedule although immunoglobulins appeared the most efficient measure. In addition, psychologic care of the patients is indicated, since disturbances in the psycho-neuroimmunologic regulation may play a significant role in the pathogenesis of the disease.

Frequent double infection with Epstein-Barr virus and human herpesvirus-6 in patients with acute infectious mononucleosis

Clinical infectious mononucleosis (IM) represents a benign self-limited form of lymphoproliferative disease which is usually caused by infection with Epstein-Barr virus (EBV). Microscopic characteristics of this lymphoproliferative disorder, however, are not ultimately specific for EBV infection, but can also be seen in infections with other lymphotropic viruses, especially of the herpesvirus family. Human herpesvirus-6 (HHV-6) infection can apparently be associated with a number of diseases also seen in EBV infection. Also, postinfectious chronic fatigue syndrome (PICFS) which may follow IM is in more than 60% of the cases accompanied by persistent active HHV-6 infection. We thus screened serologically 215 cases of acute IM for evidence for infection with EBV, HHV-6 and CMN. Patients were tentatively grouped into those having primary infection or reactivated (probably non-primary) infections. Cases were followed for two years to monitor changes in titers. Of all 215 cases, 211 (98.1%) were positive for EBV, 137 (63.7%) for primary infections, 21 (9.8%) for reactivated infection, and 53 (24.6%) for latent EBV. Thirty-three (15.3%) cases had primary HHV-6 infection, 63 (29.3%) active or reactivated HHV-6 infection, and 71 (33.9%) latent HHV-6. Double active EBV and HHV-6 infection, including primary and reactivated infections, amounted to 89 (39.5%) cases. Cytomegalovirus (CMV) antibody titers were found in 81 (37%) cases, 48 (22.3%) of which indicated latent infection and 33 (15.3%) active infection. Only two cases had evidence of active CMV infection alone, 1 cases of active CMV and HHV-6 infection. Serologic titers in 12 (5.6%) cases indicated combined active infection with CMV, EBV and HHV-6.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical indications and diagnostic techniques of human herpesvirus-6 (HHV-6) infection

The sixth member of the human herpesvirus family, HHV-6, causes early childhood infection with subsequent latency and antibody prevalence of about 60-80%. Active infection is related to a number of acute and chronic diseases such as exanthem subitum, certain cases of infectious mononucleosis and other immunoproliferative syndromes, autoimmune disorders and so-called postinfectious chronic fatigue syndrome. The clinical diagnosis of HHV-6 associated diseases requires detailed clinical differential diagnostic procedures and meticulous serological testing with exclusion of other herpesvirus infections or cross-reactivity between such infections. Diagnostic efforts, however, are warranted by certain indications for therapeutic intervention. The current review summarizes indications, techniques and limitations for the serological diagnosis of HHV-6 infection.

Alpha-1-proteinase inhibitor gene frequencies in Belgium

The alpha-1-antitrypsin phenotype was determined in cord blood of 1345 Belgian newborns by isoelectric focusing in polyacrylamide gels. Proteinase inhibitor (PI) gene frequencies were calculated. The relative gene frequency of the M allele was 0.9245, and those of S and Z alleles were 0.0543 and 0.0167 respectively. I and F alleles were less represented. These results are in agreement with population studies of neighbouring countries.

High-dose intravenous immunoglobulins in HIV-1-infected adults with AIDS-related complex and Walter-Reed 5

The influence of high-dose intravenous immunoglobulins (HD-IVIG) on the clinical status and T4 cell count of adults with AIDS-related complex (ARC) and Walter-Reed 5 (WR5) was evaluated in a randomized double-blind longitudinal study. Inclusion criteria were: (1) T4 cells less than 400/microliters and (2a) oral thrush or cutaneous anergy or (2b) two clinical ARC criteria (fever, diarrhea, weight loss, fatigue, night sweats). Thirty patients [28 males, 2 females, median age 41 (24-64) years] with ARC (n = 8), WR5 (n = 12) and both (n = 10) were stratified according to their T4 cell count (greater than or equal to vs. less than 300/microliters). Fifteen patients received 0.4 g/kg body weight IVIG and 15 placebo (albumin 0.03%) every other week for 26 weeks with follow-up for another 26 weeks. The clinical status was defined as a score consisting of fever, diarrhea, night sweats, fatigue, weight loss, oral candidiasis and mucosal or cutaneous herpes simplex. Clinical examination and routine laboratory assessments were performed before initiation of the study and before each administration, lymphocyte phenotyping every 4 weeks and cutaneous reaction, serology and lymphocyte stimulation every 12 weeks. Both groups were comparable in initial clinical symptoms and laboratory values. Seven patients developed AIDS (treatment group: 3, placebo group: 4), 1 patient died by homicide. After 26 weeks, the clinical score (particularly fatigue and fever) was significantly improved in the treatment group, while the T4 cell count and other clinical and immunological parameters remained unaltered. This limited effect was still evident at termination of the study after 52 weeks. In conclusion, HD-IVIG can improve the clinical status of patients with advanced HIV-1 infection without obviously correcting the underlying impaired cellular immunity. The substitution of intact antibodies in the state of functional hypogammaglobulinemia is suggested as possible therapeutic mechanism.

Virological examinations of patients with AIDS-related complex/Walter-Reed 5 enrolled in a double-blind placebo-controlled study with intravenous gammaglobulin administration. Prognostic value of anti-p24 determination. The ARC-IVIG Study Group

Thirty patients with AIDS-related complex/Walter-Reed 5 enrolled in a placebo-controlled double-blind study with high-dose intravenous gammaglobulin administration were tested by quantitating HIV Western blot and other serological tests for viral antibodies. Furthermore, conventional virus isolation attempts were performed. Absence or loss of p24 antibodies during the study period was associated with progression to AIDS (p = 0.01) and thereby was an earlier prognostic parameter of a poor prognosis than T4 cell count. Neither changes in antibody patterns against other HIV polypeptides, HIV titers in the immunofluorescence test nor demonstration of HIV antigen were significantly associated with progression to AIDS. Cytomegalovirus (CMV) could be isolated from two duodenal biopsies of a patient who developed AIDS at the same time, but a concomitant serological diagnosis of CMV infection was not successful. Though signs in the serology of human herpesviruses (herpes simplex virus, CMV, Epstein-Barr virus), possibly indicating a reactivation of latent infections, could be observed in some instances, a correlation with clinical symptoms or the clinical outcome was not feasible, perhaps also because of a poor standardization of some of the test kits used. All patients were positive for IgG antibodies against the three herpesviruses when entering the study. High prevalence of hepatitis B virus (HBV) markers was found (83% anti-HBc positive), only 1 patient being chronically infected and highly infectious, as shown by HBV-DNA hybridization. No significant difference between treatment and placebo group was observed with the parameters tested in this study.

Cellular immunologic parameters in HIV-positive patients with AIDS-related complex and intravenous immunoglobulin therapy

In a randomized double-blind longitudinal study with 30 HIV-1-positive patients with AIDS-related complex or stage Walter-Reed 5 disease, the effectiveness of intravenous immunoglobulin (IVIG) was tested for correcting eventual immune dysregulation. Although the IVIG-treated patients showed an improvement of their clinical score, no significant changes were observed in lymphocyte phenotypes, activation markers, immunoglobulins and subclasses, lymphocyte turnover or in indicators of acute inflammation. Since severe bacterial infections or autoimmune processes usually leading to IVIG therapy were not prevalent in the patients of the study, such therapy should probably be reserved for later stages of the disease. HIV-1 antigen expression in blood lymphocytes remained uninfluenced by IVIG treatment.

Overview of immunopathology of chronic active herpesvirus infection

Chronic latent infection with human herpesvirus is common; antibody prevalence in the general population varies from 40 to above 95%, for herpesvirus-6 at about 20%. Reactivation occurs in 5-20% of healthy persons. If reactivation coincides with impaired host response, chronic active infection may ensue. Chronic active infection by certain members of the Herpesviridae such as EBV, CMV and HHV-6 is prone to being complicated by autoimmune diseases and atypical lymphoproliferation. Its diagnosis is occasionally rendered difficult by a variety of immunologic interference factors, thus final evaluation must result from clinical, immunopathological and virological cooperation.