Apolipoproteins D and E3 exert neurotrophic and synaptogenic effects in dorsal root ganglion cell cultures

Co-cultures of 3T3-L1 adipocytes with neurons from the rat dorsal root ganglia (DRG) showed enhanced neuritogenesis and synaptogenesis. Microarray analysis for upregulated genes in adipocyte/DRG co-cultures currently points to apolipoproteins D and E (ApoD, ApoE) as influential proteins. We therefore tested adipocyte-secreted cholesterol and the carrier proteins ApoD and ApoE3. Cholesterol, ApoD, and ApoE3 each increased neurite outgrowth and upregulated the expression of presynaptic synaptophysin and synaptotagmin, as well as the postsynaptic density protein 95. The neurotrophic effects of ApoD and ApoE3 were associated with an increased expression of the low-density lipoprotein receptor and apolipoprotein E receptor 2. Simultaneous treatment with receptor-associated protein, an apolipoprotein receptor antagonist, inhibited the neurotrophic function of both apolipoproteins. The application of ApoD, ApoE3, and cholesterol to DRG cell cultures corresponded with increased expression of the chemokine stromal cell-derived factor 1 and its receptor CXC chemokine receptor 4 (CXCR4). Surprisingly, the inhibition of CXCR4 by the antagonistic drug AMD3100 decreased the apolipoprotein/cholesterol dependent neurotrophic effects. We thus assume that apolipoprotein-induced neuritogenesis in DRG cells interferes with CXCR4 signaling, and that adipocyte-derived apolipoproteins might be helpful in nerve repair.

Effect of oral fructose load on serum uric acid and lipids in kidney transplant recipients treated with cyclosporine or tacrolimus

Hyperuricemia, frequently observed following kidney transplantation, may adversely affect graft survival. Although hyperuricemia is a well-known adverse effect of cyclosporine (CsA), a similar effect of tacrolimus (Tac) remains debatable. Hyperuricemia is also seen after oral fructose intake in beverages and processed foods. This sugar is blamed for the epidemic of obesity and metabolic syndrome. The aim of our study was to compare the effects of CsA and Tac on an acute oral fructose load in terms of plasma uric acid, serum lipids, and blood pressure in kidney transplant patients. Thirty-two kidney transplant recipients treated with CsA- or Tac-based triple (calcineurin inhibitor + mycophenolate mofetil + prednisone) immunosuppressive therapy displaying stable allograft function (mean glomerular filtration rate = 53 mL/min/1.73m(2)) received an oral challenge with 70 g of fructose. Serum uric acid, lipids, and blood pressure were measured before as well as 60, 120, 180, and 240 minutes after fructose administration. A significant increase in serum uric acid was observed in both groups after oral fructose administration (P < .001). A peak increase in serum uric acid was recorded at 120 minutes after fructose intake. Serum total, LDL, and HDL cholesterol also significantly decreased and serum triglycerides increased to a similar extent in both CsA and Tac groups. No significant changes in blood pressure were observed after fructose consumption. Oral fructose intake induced an acute rise in serum uric acid and triglycerides and decrease in serum cholesterol among kidney transplant recipients. Those changes were similar among patients treated with CsA or Tac.

Hepatitis C seropositivity and kidney function decline among women with HIV: data from the Women's Interagency HIV Study

BACKGROUND

How coinfection with hepatitis C virus (HCV) impacts on the trajectory of kidney function in human immunodeficiency virus (HIV)-infected patients is unclear. This study examined the effect of HCV infection on kidney function over time in women infected with HIV.

STUDY DESIGN

Retrospective observational cohort.

SETTING & PARTICIPANTS

Study sample included participants from the Women's Interagency HIV Study who were HIV infected and had undergone HCV antibody testing and serum creatinine measurement at baseline.

PREDICTOR

HCV seropositivity.

OUTCOMES & MEASUREMENT

Estimated glomerular filtration rate (eGFR) calculated from semi-annual serum creatinine measurements using the 4-variable Modification of Diet in Renal Diseases (MDRD) Study equation. Linear mixed models were used to evaluate the independent effect of HCV seropositivity on eGFR over time, adjusting for demographic factors, comorbid conditions, illicit drug use, measures of HIV disease status, use of medications, and interactions with baseline low eGFR (<60 mL/min/1.73 m(2)).

RESULTS

Of 2,684 HIV-infected women, 952 (35%) were found to be HCV seropositive. In 180 women with chronic kidney disease (CKD) at baseline (eGFR < 60 mL/min/1.73 m(2)), HCV seropositivity was independently associated with a fully adjusted net decrease in eGFR of approximately 5% per year (95% confidence interval, 3.2 to 7.2) relative to women who were seronegative. In contrast, HCV infection was not independently associated with a decrease in eGFR in women without low eGFR at baseline (P < 0.001 for interaction).

LIMITATIONS

The MDRD Study equation has not been validated as a measure of GFR in persons with HIV or HCV infection. Proteinuria was not included in the study analysis. Because the study is observational, effects of residual confounding cannot be excluded.

CONCLUSIONS

In HIV-infected women with CKD, coinfection with HCV is associated with a modest, but statistically significant, decrease in eGFR over time. More careful monitoring of kidney function may be warranted for HIV-infected patients with CKD who are also coinfected with HCV.

Isolation and characterization of caprine arthritis encephalitis virus in goats from Poland

The caprine arthritis-encephalitis virus (CAEV) was isolated from monocyte-derived macrophages (M/M), but not from PBMC of seropositive goats by co-cultivation with goat synovial membrane cells. Out of eight M/M co-cultures, CAEV was evidenced by the syncytia formation and presence of proviral DNA in two and four cultures, respectively. Two virus isolates from co-cultures showing cytopathic effects were further confirmed as CAEV by western blotting, PCR, and sequence analysis. The nucleotide sequence of gag gene showed 92.0% and 90.3% homology to the prototype CAEV-Co strain. Supernatants harvested from these cultures induced syncytia when cultured with uninfected cells and the resultant titer was 10(3.5) and 10(2.5) TCID50 per ml. New CAEV isolates are suitable candidates for further analysis of their genetic and biological properties.

Nanoindentation of heterogeneous carbonaceous films containing Ni nano-crystals

Composite films of nano-size nickel grains embedded in a carbonaceous matrix are synthesized by a PVD process of C(60) fullerenes and Ni acetate. The morphology of the nano-composite films is characterized by TEM, selected area electron diffraction, chemical analysis and AFM. Correlations with deposition parameters and typical structure changes are found. The mechanical properties are analyzed by nanoindentation. The load-displacement charts show typical pop-ins correlated with the heterogeneous nano-structure. The depth dependent hardness and indentation modulus vary according to the nano-composite structure and reflect the changes of the mechanical properties in the film.

Agreement between ELISA and complement fixation test used for diagnosing of paratuberculosis in goats

An ELISA with a lipoarabinomannan as an antigen, developed for diagnosis of bovine paratuberculosis, has been adapted for use in goats, and compared with complement fixation test. Kappa value of 0.62 indicated good agreement between CFT and the adapted ELISA and proved that the investigated ELISA may be helpful in diagnosis of Mycobacterium avium subsp. paratuberculosis infection in goats. The ELISA has been used to screen a randomly selected representative sample of Polish breeding goat population (21.78% of herds, 21.33% of goats). It has been demonstrated that only 2.42% of animals coming from 15.79% of herds were seropositive. Within-herd seroprevalence varied from 1.69% to 38.10%. Most of the infected animals (67.07%) were 3- 4-years-old. No seropositive cases were found in group up to 1-year-old animals.

In vitro substance P-dependent induction of bone marrow cells in common (CD10) acute lymphoblastic leukaemia

The aim of the present research was to investigate the possible in vitro stimulatory effect of substance P (SP) on blasts induction in childhood common acute lymphoblastic leukaemia (ALL). Bone marrow aspirates were incubated with SP receptor agonist or antagonist (spantide) and subsequently assayed for the presence of human interleukin (IL)-1b using ELISA kit. Blast cells incubated with SP receptor agonist were found to result in a significant increase of IL-1b concentration while incubated with spantide resulted in control levels of IL-1b. These findings suggest the novel possible role of SP in blasts proliferation in childhood ALL of common (CD10) origin.

Canine hip dysplasia of selected breeds--results obtained by two Polish clinics based on radiological examination conducted in 1997-2006

Canine Hip Dysplasia (CHD) is still a significant health problem among dogs of so called predisposed breeds where this disease is revealed even among 30% individuals of the whole population. The present results were obtained by two clinics and deal with CHD occurrence among the most frequently and predisposed breeds in Olsztyn and Siemianowice Slaskie/Upper Silesia, Poland. Radiographs of hip joints were described using Riser's method. Altogether 2279 dog were examined including 2113 animals which were analysed. The German Shepherd Dog was the prevalent breed found in both clinics, but CHD was not common in this breed. In the Olsztyn Clinic, the most numerous group affected by CHD was Neapolitan Mastiff (60%), while in the Siemianowice Slaskie Clinic, dysplasia dominated in Bernese Mountain Dog (46%).

The significance of caveolin-1 expression in parietal epithelial cells of Bowman's capsule

AIMS

To analyse the expression of caveolin-1 in normal human kidney and during diseases leading to nephrotic syndrome in children and to compare its pattern with those observed in control samples, both human and animal.

METHODS AND RESULTS

The study group was composed of 104 children diagnosed with minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), lupus glomerulonephritis (LGN) and Schönlein-Henoch glomerulopathy (SH). The research protocol employed direct immunohistochemical assay with the use of mono- and polyclonal antibodies against caveolins. Kidney samples of Wistar rats, wild-type mice and caveolin-1-deficient mice were also analysed. In the control human samples, caveolin-1 was most abundant in the muscle layer of blood vessels and parietal epithelial cells (PECs). Its expression in PECs was significantly lower in children diagnosed with FSGS and LGN than in those with MCD, SH or in controls. In the control animal tissues, except for knock-out mice, caveolin-1 was present in distal convoluted tubules, PECs, endothelial cells and muscle.

CONCLUSIONS

Caveolae are extremely stable elements of PECs and can be excluded from their cell membrane only in response to the dramatic cell reconstruction observed in FSGS and LGN.

Immunohistochemical detection of galectin-1 in renal biopsy specimens of children and its possible role in proteinuric glomerulopathies

AIMS

Galectin-1 is an endogenous lectin that specifically binds to beta-galactoside structures. It has been associated with developmental mechanisms ranging from differentiation to apoptosis and exerts immunoregulatory functions in autoimmune diseases. The aim was to determine the immunohistochemical expression of galectin-1 in renal biopsy specimens of children with primary idiopathic proteinuric glomerulopathies.

METHODS AND RESULTS

We examined 18 children with minimal change disease (MCD), 30 with diffuse mesangial proliferation (DMP) and 11 with focal segmental glomerulosclerosis (FSGS). An indirect immunohistochemical protocol using a polyclonal antibody directed against galectin-1 was applied. Galectin-1 was detected in renal podocytes in DMP and FSGS cases, while control glomeruli and MCD were negative. Galectin-1 immunoreactivity was found within parietal epithelial cells in patients with FSGS.

CONCLUSIONS

These results suggest a possible role for galectin-1 in the pathogenesis of primary glomerulopathies in children as a kind of podocyte-related self-protective activity and probably involvement of epithelial cells of Bowman's capsule in inflammatory processes. Immunohistochemistry using galectin-1 antibodies may further be helpful in histological distinction between MCD and DMP.

Prevalence and long-term effects of occult hepatitis B virus infection in HIV-infected women

Occult hepatitis B virus (HBV) infection is of concern in human immunodeficiency virus (HIV)-infected persons. We observed that 2% of 400 HIV-infected women with antibodies to hepatitis B core antigen alone had occult HBV infection (i.e., detectable HBV DNA in the absence of HBV surface antigen). CD4 cell counts of <200 cells/mm3 were more common among occult HBV-infected women than among those without occult HBV infection. Aminotransferase levels did not appear to be associated with being positive for HBV DNA.

Immunocytochemical and biochemical detection of EMMPRIN in the rat tooth germ: differentiation-dependent co-expression with MMPs and co-localization with caveolin-1 in membrane rafts of dental epithelial cells

In tooth development matrix metalloproteinases (MMPs) are under the control of several regulatory mechanisms including the upregulation of expression by inducers and downregulation by inhibitors. The aim of the present study was to monitor the occurrence and distribution pattern of the extracellular matrix metalloproteinase inducer (EMMPRIN), the metalloproteinases MMP-2 and MT1-MMP and caveolin-1 during the cap and bell stage of rat molar tooth germs by means of immunocytochemistry. Strong EMMPRIN immunoreactivity was detected on the cell membranes of ameloblasts and cells of the stratum intermedium in the bell stage of the enamel organ. Differentiating odontoblasts exhibited intense EMMPRIN immunoreactivity, especially at their distal ends. Caveolin-1 immunoreactivity was evident in cells of the internal enamel epithelium and in ameloblasts. Double immunofluorescence studies revealed a focal co-localization between caveolin-1 and EMMPRIN in ameloblastic cells. Finally, western blotting experiments demonstrated the expression of EMMPRIN and caveolin-1 in dental epithelial cells (HAT-7 cells). A substantial part of EMMPRIN was detected in the detergent-insoluble caveolin-1-containing low-density raft membrane fraction of HAT-7 cells suggesting a partial localization within lipid rafts. The differentiation-dependent co-expression of MMPs with EMMPRIN in the enamel organ and in odontoblasts indicates that EMMPRIN takes part in the induction of proteolytic enzymes in the rat tooth germ. The localization of EMMPRIN in membrane rafts provides a basis for further investigations on the role of caveolin-1 in EMMPRIN-mediated signal transduction cascades in ameloblasts.

Peptidergic and Nitrergic Innervation of the Pineal Gland in the Domestic Pig: An Immunohistochemical Study

The presence and co-localization of vasoactive intestinal polypeptide (VIP), peptide N-terminal histidine C-terminal isoleucine (PHI), pituitary adenylate cyclase-activating peptide (PACAP), somatostatin (SOM), calcitonin gene-related peptide (CGRP), substance P (SP) and the neuronal isoform of nitric oxide synthase (NOS) were studied in neuronal structures of the pig pineal gland. Paraformaldehyde-fixed pineals of 3-month-old gilts were sliced into serial cryostat sections, which were subjected to a set of double immunofluorescence stainings. Based on the co-existence patterns of neuropeptides, five populations of nerve fibres supplying the pig pineal were distinguished: (1) PHI-positive, (2) PACAP-positive, (3) SOM-positive, (4) SP/CGRP-positive and (5) SP-positive/CGRP-negative. Only a subpopulation of PHI-positive fibres contained VIP at the level detectable by immunofluorescence. NOS was found in some intrapineal PHI- and VIP-positive fibres. PHI-, VIP- and NOS-positive nerve fibres were more numerous in the peripheral than in the central part of the pineal. PACAP-positive fibres were equally distributed within the gland. The density of SOM-positive fibres was higher in the ventro-proximal than in the dorso-distal part of the pineal. SOM was also detected in some neuronal-like cells or specialized pinealocytes situated in the central region of the gland. Two populations of fibres containing SP were found: CGRP-positive, present in the distal and central parts of the pineal as well as CGRP-negative, localized in the proximal compartment of the gland.

Foetal haemoglobin-blood cells (F-cells) as a feature of embryonic tumours (blastomas)

Tumour markers are important in the diagnosis and monitoring of many tumours. This study tested the hypothesis that an oncofoetal protein, foetal haemoglobin (HbF) is a potential tumour marker in embryonic tumours, useful for management. An immunohistochemical investigation of HbF blood cell (Fc) distribution was carried out in tumours and in bone marrow samples from 83 children and 13 adults with various embryonic tumours (blastomas), and in bone marrow samples of 24 leukaemia patients. In the three, main blastoma types, nephroblastoma (Wilms' tumour), neuroblastoma and retinoblastoma, where all the patients, except two, were children, around 80% of the tumour samples had Fc within proliferating blood vessels and spaces between tumour cells. In parallel, clusters of Fc, mostly F-erythroblasts (Feb), were distributed in the bone marrow of some of those patients and in the bone marrow of 79% of the leukaemia patients. Foetal haemoglobin, as well as being a potential prognostic cancer marker, is a potential indicator of DNA hypomethylation implicated in the development of these tumours, as well as in others previously noted for the presence of HbF.

The significance of VEGF-C/VEGFR-2 interaction in the neovascularization and prognosis of nephroblastoma (Wilms' tumour)

AIM

To investigate the immunohistochemical expression of vascular endothelial growth factor (VEGF)-C and VEGFR-2 in nephroblastoma tissue and correlate their presence with the survival rate of children diagnosed with stage III Wilms' tumour.

METHODS AND RESULTS

The material included nephroblastoma tissue obtained from 25 children hospitalized in the Department of Paediatric Oncology, Haematology and Transplantology between 1997 and 2003. VEGF-C and VEGFR-2 expression was evaluated by immunohistochemical assay. VEGF-C was expressed in all cells of the blastemal component and in 30% of tumour cells in the stromal part. It was absent from epithelial elements. VEGFR-2 expression was spread over the surface of numerous stromal cells as well as all the epithelial cells forming dysplastic tubules. The blastemal component of Wilms' tumour was VEGFR-2-negative. VEGF-C-immunopositive stromal cells were situated in the closest proximity to VEGF-C-immunonegative but VEGFR-2-immunoreactive tubules. VEGF-C expression was of prognostic value for both clinical progression (P = 0.0005) and tumour-related death (P = 0.0365).

CONCLUSIONS

VEGF-C expression in Wilms' tumour constitutes a potent unfavourable risk factor and may direct future antiangiogenic treatment strategies. The proximity of VEGF-C and VEGFR-2 in the stromal and epithelial components of nephroblastoma could be the neoplastic equivalent of the binary VEGF-C function observed in epithelial and endothelial morphogenesis.

Applicability of endoscopic examination as a diagnostic approach in urinary tract ailments in dogs

The purpose of this study was to evaluate the applicability of endoscopic examination as a diagnostic method in urethra and bladder ailments in dogs. The experiment involved 60 dogs of different breeds and gender, weighing from 5 to 65 kg, aged between 7 months and 12 years. The dogs were divided into two groups. Group I consisted of clinically healthy animals on which all the lower urinary tract endoscopic examinations described in the literature as well as biopsies of mucosa were performed. Group II consisted of clinical patients, on which endoscopic diagnostic examination was conducted and, on some of them, biopsies for histopathologic examination were made. The results of the experiment suggest that the lower urinary track endoscopy is a suitable diagnostic technique for recognition and differentiation of mucosa inflammation, establishment of causes of haematuria, diagnostics of neoplasms and detection of the existence of an ectopic ureter. Biopsy and histopathologic examination improved the diagnostic value of endoscopy. The techniques tested in our study, inclusive of more invasive method like PPC and cystoscopy on males preceded by the perineal urethrotomy, enable doctors to perform the lower urinary tract endoscopic examination on dogs, especially up to 5 kg. regardless of their gender.

Usefulness of endoscopic examination for the diagnosis of inflammatory bowel disease in the dog

The usefulness of endoscopic examination for the diagnosis and treatment of chronic enteritis in dogs was determined in this study. It was demonstrated, based on a clinical case, that endoscopy is essential for IBD diagnosis in dogs. Endoscopy also helps to estimate the efficiency of the treatment strategy applied. Nonspecific clinical examination results as well as a predominating lack of deviation in laboratory parameters make endoscopy the basic examination technique in mild and moderately advanced forms of chronic enteritis in the dog.

Blinded, multicenter comparison of methods to detect a drug-resistant mutant of human immunodeficiency virus type 1 at low frequency

We determined the abilities of 10 technologies to detect and quantify a common drug-resistant mutant of human immunodeficiency virus type 1 (lysine to asparagine at codon 103 of the reverse transcriptase) using a blinded test panel containing mutant-wild-type mixtures ranging from 0.01% to 100% mutant. Two technologies, allele-specific reverse transcriptase PCR and a Ty1HRT yeast system, could quantify the mutant down to 0.1 to 0.4%. These technologies should help define the impact of low-frequency drug-resistant mutants on response to antiretroviral therapy.

The predicting role of substance P in the neoplastic transformation of the hypoplastic bone marrow

AIMS

To estimate the expression of substance P in the haematopoietic cells of hypoplastic bone marrow and define its relationship with the course of bone marrow hypoplasia.

METHODS

Bone marrow specimens were obtained from 42 children with bone marrow hypoplasia who were hospitalised in the Department of Pediatric Oncology, Hematology and Transplantology, Poznan University of Medical Sciences, Poznan, Poland, between 1996 and 2003. Substance P and Ki-67 expression were evaluated using immunochemical and hybridocytochemical assays.

RESULTS

The expression of substance P (as evidenced by both immunocytochemical and hybridisation techniques) was confirmed in the cytoplasm of B lymphocytes in 8 of 11 children who developed acute leukaemia in 45 (SD 12) days. The percentage of substance P-positive cells ranged from 67.6 to 95.8 (mean of 81.5% cells with immunocytochemistry and 84.3% with in situ hybridisation). The risk of development of leukaemia secondary to bone marrow hypoplasia was found to be significant (p<0.001) in those children who expressed substance P in normal-looking lymphocytes at the initial bone marrow evaluation.

CONCLUSIONS

The presence of substance P in B lymphocytes of hypoplastic bone marrow may predict its neoplastic transformation. A marked correlation between substance P-positive bone marrow pattern and the expansion of tumour cells may prove the potential value of this oligopeptide in the pathogenesis of leukaemia.

Histology and ultrastructure of the pineal organ in the domestic goose

The pineal organs of 14-week-old domestic geese were investigated with light and electron microscopy. The pineals consisted of a wide distal part and a narrow middle-proximal one. The glands were attached to the intercommissural region via the choroid plexus. The pineal parenchyma was formed by round or elongated follicles. The follicular wall was composed predominantly by cells immunoreactive with antibodies against hydroxyindolo-O-methyltransferase (HIOMT) or glial fibrillary acid protein (GFAP). They formed two or more layers. HIOMT-positive elements were represented by elongated cells bordering the follicular lumen and oval cells located in the external layer of the follicular wall. These cells were identified in ultrastructural studies as rudimentary-receptor pinealocytes and secretory pinealocytes, respectively. Among rudimentary-receptor pinealocytes two types of cells, designed as A and B, were distinguished due to structural differences. Type A cells extended through the whole follicular wall and showed regular stratified distribution of organelles in well-recognizable zones with rough endoplasmic reticulum, the Golgi apparatus and mitochondria. Type B cells, like type A pinealocytes, contacted the pineal lumen and showed polarity of their internal structure. However, they were markedly shorter than the cells of type A and lacked stratified distribution of organelles. Secretory pinealocytes contained irregularly dispersed organelles. A prominent feature of all types of goose pinealocytes was the presence of numerous dense core vesicles. The population of GFAP-positive cells consisted of ependymal-like supporting cells and astrocyte-like cells.

Vascular endothelial growth factor C—a potent risk factor in childhood acute lymphoblastic leukaemia: an immunocytochemical approach

AIMS

To investigate the immunocytochemical expression of vascular endothelial growth factor C (VEGF-C) and its receptors (VEGFR-2 and VEGFR-3) in childhood acute lymphoblastic leukaemia (ALL) blasts and to determine the possible role of this complex in the pathogenesis and prognosis of ALL.

METHODS AND RESULTS

Bone marrow samples were taken from 120 children diagnosed with ALL. An indirect immunocytochemical procedure was performed with the use of monoclonal mouse anti-human antibodies against VEGF-C, VEGFR-2 and VEGFR-3 (diluted 1 : 100). The immunocytochemical expression of VEGF-C was confirmed exclusively in the cytoplasm of ALL lymphoblasts (the mean percentage was 36.4 +/- 7.2). It was absent from the cytoplasm of normal haematopoietic cells in the control group. No VEGFR-2 or VEGFR-3 expression was detected in the children of either the study or control groups. The risk of induction failure or leukaemic relapse was found to be significant in all VEGF-C+ patients (P < 0.0001 and P < 0.02, respectively; Fisher's exact test).

CONCLUSIONS

The absence of VEGF-C in blast cells predicts long-lasting remission in all leukaemic children. Our findings also suggest that leukaemic cell invasion, following VEGF-C-driven lymphangiogenesis, could be related to a mediating role of this peptide produced by blast cells themselves.

Selection of different 5' untranslated region hepatitis C virus variants during post-transfusion and post-transplantation infection

BACKGROUND

Hepatitis C virus (HCV) translation is initiated in a cap-independent manner by an internal ribosome entry site (IRES) located within the 5' untranslated region (5'UTR). Sequence changes in this region could affect translation efficiency and presumably viral replication.

AIM

To determine translation efficiency of 5'UTR variants developing during post-transfusion hepatitis C in two immunocompetent subjects and in two immunosuppressed liver recipients with recurrent HCV.

METHODS

Sequential samples were screened for 5'UTR changes by single-strand conformation polymorphism followed by cloning and sequencing whenever band pattern suggested sequence changes. 5'UTR variants were tested for IRES activity using a bicistronic dual luciferase expression plasmid transfected into HepG2 and Huh7 cell-lines.

RESULTS

In the transfused patients, translation efficiency of 5'UTR variants from early post-transfusion samples was 5.1- to 13.7-fold higher than that of predominant variants found in late follow-up samples. Post-transplant variants in the other two patients had 2.6- to 5.9-fold higher translation efficiency than those present only in pretransplant samples.

CONCLUSION

In the immunocompetent host there may be selection of low translation efficiency HCV variants over the course of infection. However, in immunosuppressed subjects the opposite seems to be true as low translation efficiency variants are superseded by high translation efficiency variants.

Molecular fluorescence from H2TBP porphyrin film on Ag substrate excited by tunneling electrons

Molecular fluorescence from H(2)TBP porphyrin (H(2)TBPP) films on Ag substrate is excited by a scanning tunneling microscope (STM) at ambient conditions. The molecular films are prepared by spin-casting method. The thickness of films can be controlled by the times of dropping H(2)TBPP solution. Molecular fluorescence of as-above prepared H(2)TBPP films with 4-14nm thickness at both polarities of applied bias voltage are well defined in good matching with its photoluminescence spectrum, which suggests the same decay channel associated with the HOMO-LUMO radiative transitions similar to H(2)TBPP/Au. The thickness dependence of light emission intensity of molecular fluorescence has been studied. The results show that for thicker film, molecular fluoresceence tends to be much stronger due to the effective decoupling of the emitter from the metal substrate.

Evaluating the impact of hepatitis C virus (HCV) on highly active antiretroviral therapy-mediated immune responses in HCV/HIV-coinfected women: role of HCV on expression of primed/memory T cells

OBJECTIVE

To evaluate the impact of hepatitis C virus (HCV) on the immune system before receipt of highly active antiretroviral therapy (HAART) and on immune recovery after receipt of HAART among human immunodeficiency virus (HIV)/HCV-coinfected women enrolled in the Women's Interagency HIV Study.

METHODS

The study included 294 HIV-infected women who initiated HAART and attended 2 follow-up visits. The women were grouped on the basis of positive HCV antibody and HCV RNA tests. There were 148 women who were HCV antibody negative, 34 who were HCV antibody positive but RNA negative, and 112 who were HCV antibody and RNA positive. Immune recovery was measured by flow-cytometric assessment for markers of activation and maturation on CD4+ and CD8+ T cells. Data analysis used repeated measures of variance.Results. HIV/HCV coinfection is associated with an increased number of CD4+ and CD8+ primed/memory T cells. HIV/HCV coinfection, however, did not affect any further decreases in CD4+ or CD4+ and CD8+ naive/memory T cell counts or enhanced T cell activation. HIV/HCV coinfection also did not affect HAART responses in the CD4+ and CD8+ T cell compartment.

CONCLUSIONS

HCV does not affect immune responses to HAART in HIV/HCV-coinfected individuals but is associated with an expansion of CD4+ and CD8+ memory T cell subsets. Functional impairment in the CD4+ and CD8+ T cell compartments still needs to be assessed in coinfected patients.

Ezrin--a useful factor in the prognosis of nephrotic syndrome in children: an immunohistochemical approach

BACKGROUND

Minimal change disease (MCD) and diffuse mesangial proliferation (DMP) are the most common pathomorphological forms of nephrotic syndrome glomerulopathies in children. The clinical course of DMP can be characterised by either DMP-sensitivity (DMP-S) or DMP-resistance (DMP-R) to steroids, resulting in an unfavourable course of the glomerulopathy. Although the clinical processes of DMP-S and DMP-R are initially identical, resistance to steroids may be foreseen by the immunohistochemical expression of cytoskeleton-associated proteins in podocytes.

AIMS

To estimate the immunohistochemical expression of ezrin in children with MCD, DMP and focal segmental glomerulosclerosis (FSGS) and to evaluate its usefulness in predicting resistance to steroids.

MATERIALS AND METHODS

Renal biopsy specimens of patients with MCD (n = 15), DMP (n = 16) and FSGS (n = 6) were taken. The control tissue consisted of normal-appearing cortex taken from kidneys resected for localised neoplasms (n = 6). The indirect immunohistochemical protocol for the use of a monoclonal antibody directed against ezrin was used.

RESULTS

The immunohistochemical expression of ezrin in cases progressively reduced from MCD to DMP-S to DMP-R to FSGS. Except for DMP-R and FSGS (p>0.05), the difference in ezrin expression in podocytes was significant.

CONCLUSION

Ezrin can be a potent marker of podocyte injury (podocytopathy) and may help in the histological qualification of MCD, DMP and FSGS. The increased permeability of the filtration barrier in steroid-resistant and proteinuric glomerulopathies may be a consequence of subcellular changes in podocyte-associated proteins following decreased expression of ezrin.

Prognostic value of stage IV neuroblastoma metastatic immunophenotype in the bone marrow: preliminary report

AIM

To correlate the immunophenotype of metastatic cells in the bone marrow of patients with neuroblastoma with early treatment failure.

METHODS

The studies were performed on bone marrow material obtained from children treated in the department of paediatric oncology, haematology, and transplantology, Poznan University of Medical Sciences, Poland from 1996 to 2003. Immunocytochemical analysis of nervous tissue markers (using the immunomax technique) was performed on 108 bone marrow preparations obtained from 36 children diagnosed with neuroblastoma (stage IV with bone marrow metastases). The analysis included expression of PGP 9.5 protein, substance P, chromogranin A, bombesin, galanin, neuropeptide Y (NPY), and vasoactive intestinal peptide in neuroblastoma metastatic cells defined by the expression of neurone specific enolase.

RESULTS

Nineteen relapses occurred within 12 months of the end of treatment. Correlation between the various markers studied and early treatment failure, using Fisher's exact test, revealed that chromogranin A and NPY are strong indicators of an unfavourable prognosis in patients with stage IV neuroblastoma (p < 0.001 and p < 0.0002, respectively).

CONCLUSION

Determination of metastatic cell immunophenotypes in bone marrow (particularly chromogranin A and NPY) may help establish the short term prognosis in children with neuroblastoma.

Postnatal development of the pineal gland in the goat (Capra hircus)--light and electron microscopy studies

This study was conducted to investigate structural transformations of the goat pineal gland during postnatal development. The pineals of newborn, 4-week-, 4-month-, 1-year- and 3-year-old male goats were prepared for qualitative and quantitative investigations at both light and transmission electron microscopy levels. In the first 4 months after birth, the pinealocytes developed very intensively, which was connected with enlargement of their volume as well as distinct qualitative and quantitative transformations of their cytoplasmic organelles. Parallel to these changes, the pineal parenchyma underwent deep reorganization and the mosaic pattern, characteristic for newborns, disappeared. At the same time the meshwork of blood vessels supporting the goat pineal gland developed conspicuously. From fourth months to one year of postnatal life continuation of the growth of some pinealocyte organelles and very intensive development of all components of the pineal connective tissue were observed. In the three-year-old goats some decrease in the relative volume of most cytoplasmic structures of pinealocytes as well as increase in collagen fibers in stroma were noticed. The investigations established intensive growth of the goat pineal to the age of 4 months, which included mainly some increase in the pinealocyte and their structures. The pineal gland of 4-month- and 1-year-old goats showed morphological features which are considered as symptoms of high secretory activity. The structure of the pineal gland in 3-year-old animals and the changes observed both in their pinealocytes and connective tissue in comparison with 1-year-old individuals point to some decrease in the goat pineal activity in this age.

Neuropsychological functioning in a cohort of HIV- and hepatitis C virus-infected women

OBJECTIVE

To evaluate the neurocognitive function in 220 women enrolled in the Women's Interagency HIV Study (WIHS), a study of disease progression in women living with HIV/AIDS and in HIV-negative controls.

METHODS

We evaluated the prevalence of abnormal neuropsychological (NP) results in hepatitis C virus (HCV)-positive compared with HCV-negative women in combination with HIV serostatus.

RESULTS

NP impairment was significantly higher for HCV-positive women in comparison with HCV-negative women [odds ratio (OR), 2.03; 95% confidence interval (CI), 1.17-3.51]. Women co-infected with HCV and HIV demonstrated greater abnormal NP performance than those not infected with either, particularly if there was evidence of CD4 T-lymphocyte immunosuppression [> 200 x 10(6) CD4 cells/l (OR, 3.48; 95% CI, 1.49-8.15) and < or = 200 x 10(6) CD4 cells/l (OR, 5.38; 95% CI, 1.46-19.84)]. Women who were HCV-positive/HIV-positive and not taking antiretroviral therapy (ART) were more likely (OR, 7.03; 95% CI, 2.63-18.82) to demonstrate NP impairment than those who were HCV-negative/HIV-negative. In analyses controlling separately for education, intelligence quotient, depression, sedating drug use, head injury, ethnicity, and history of substance use, HCV continued to significantly predict NP impairment. The HCV effect did not reach significance when controlling for age in bivariate or multivariate analyses although the odds ratio for NP abnormalities in HCV-infected patients was only slightly reduced (ORs above 1.9). After testing for an interaction between age and infection status, we conducted age-stratified analysis and showed a significant effect of infection status for those aged under 40 years.

CONCLUSIONS

The effect of aging on co-infected populations will require further study. This study has demonstrated the association of HCV with the risk of neurocognitive impairment in women living with HIV/AIDS and suggests that co-infection has an additive effect.

Vascular endothelial growth factor (VEGF-C1)-dependent inflammatory response of podocytes in nephrotic syndrome glomerulopathies in children: an immunohistochemical approach

AIMS

To analyse expression and distribution of vascular endothelial growth factor (VEGF-C1), podocalyxin and synaptopodin within renal tissue in nephrotic syndrome glomerulopathies in children.

METHODS AND RESULTS

Renal biopsies performed at the time and in the manner recommended by the World Health Organization. The study group consisted of submicroscopic glomerulonephritis (n = 10), diffuse mesangial proliferation (n = 14) and focal segmental glomerulosclerosis (n = 5). The control tissue consisted of macroscopically normal appearing cortex taken from kidneys resected for localized neoplasms (n = 3). Material for immunohistochemistry was fixed in Bouin's solution and embedded in paraffin. Indirect immunohistochemistry using monoclonal anti-human antibodies directed against VEGF-C1, podocalyxin and synaptopodin was employed. The distribution of markers was quantified by computerized image analysis. In non-sclerosed glomeruli (within podocyte cytoplasm), VEGF-C1 was more expressed in podocytes of all groups (P < 0.0002), while the distribution of synaptopodin was less expressed in all groups (P < 0.0002). There was no statistical difference between all groups in the expression of podocalyxin.

CONCLUSIONS

The increased permeability of the filtration barrier in steroid-resistant glomerulopathies may be a consequence of subcellular changes in podocytes resulting from decreased expression of synaptopodin. Moreover, impaired permeability of endothelium could be secondary to increased expression of podocyte-derived VEGF-C1.

Analysis of hepatitis C virus quasispecies transmission and evolution in patients infected through blood transfusion

BACKGROUND & AIMS

Studies on hepatitis C virus (HCV) quasispecies dynamics in the natural course of infection are rare owing to difficulties in obtaining samples from the early phase of infection.

METHODS

We studied 15 patients from the Transfusion-Transmitted Viruses Study who seroconverted to anti-HCV after receiving infected blood. Follow-up serum samples were collected every 2-3 weeks for 6 months, at 10 months, and at 11-16 years. Viral quasispecies in the second envelope hypervariable region 1 (E2/HVR1) and 5' untranslated region (5'UTR) were analyzed with single-strand conformation polymorphism (SSCP) and heteroduplex mobility assay (HMA).

RESULTS

Seven patients cleared infection within 7-24 weeks (mean, 14.0 wk) and 3 patients eventually became anti-HCV negative. In 6 patients with resolving hepatitis the SSCP band pattern remained stable, whereas in one patient minor changes appeared before clearance. In contrast, in all 8 patients progressing to chronicity, major changes in the E2/HVR1 quasispecies developed at 8-22 weeks (mean, 13.1 wk). Shannon entropy and medium mobility shift values derived from HMA gels remained stable in patients with resolving hepatitis but changed in those who developed chronic infection. Only 2 patients showed minor changes in 5'UTR. A decrease in E2/HVR1 complexity at the time of transmission (bottleneck) was found in 5 patients altogether.

CONCLUSIONS

Changes in E2/HVR1 quasispecies 8-22 weeks after infection, likely caused by mounting immune pressure, were predictive of ensuing chronic infection, whereas stability was associated with resolution. Our study also showed that composition of HCV quasispecies may be preserved during transmission from host to host.

Longitudinal effect of antiretroviral therapy on markers of hepatic toxicity: impact of hepatitis C coinfection

To characterize longitudinal hepatic toxicity of antiretroviral therapy in HIV-infected women with and without hepatitis C virus (HCV) infection, we measured alanine and aspartate aminotransferase values among women initiating highly active antiretroviral therapy (HAART). For 312 HIV/HCV coinfected women who received HAART for a mean of 1.8 years, the prevalence of elevated aminotransferase levels >3 times and >5 times the upper limit of normal (ULN) was low (<12% and <4%, respectively), and the prevalence of elevated aminotransferase levels declined over time. When we analyzed trends in aminotransferase levels according to type of HAART received among HCV-infected and uninfected women, we found that mean aminotransferase levels declined among 539 women receiving therapy with protease inhibitors (decreases of 5.34%-4.23% of the ULN per year; P values for trend of.007-.06), but mean values among 128 women receiving therapy with nonnucleoside reverse-transcriptase inhibitors remained stable (from decreases of 1.65% to increases of 7.57% of the ULN per year; P values of.19-.71). Our findings lend support to assertions that antiretroviral therapy is safe for women with HCV infection.

Hepatitis C virus quasi-species dynamics predict progression of fibrosis after liver transplantation

BACKGROUND

The dynamics of hepatitis C virus (HCV) quasi species in the E2 region may correlate with the course of infection after orthotopic liver transplantation (OLT).

METHODS

Thirty-four patients who underwent transplantation for HCV-related cirrhosis were studied. Serum and liver samples were available before OLT and at 1 week, 4 months, and 1 year after OLT. Patients were divided into group 1 (Knodell/Ishak fibrosis stage [FS] at 1 year, <2) and group 2 (FS at 1 year, > or =2). Complexity was estimated by the number of bands in a single-strand conformational polymorphism assay, whereas diversity was measured by Shannon entropy (SE) and median mobility shift (MMS) values derived from the heteroduplex mobility assay. Diversity dynamics were measured at transmission (before OLT vs. 1 week after OLT) and after OLT (1 week after OLT vs. 1 year after OLT).

RESULTS

Complexity was higher in group 1 patients than in group 2 patients before OLT (P<.02) and at 1 week after OLT (P<.04). Diversity decreased in group 1 at transmission, as measured by either SE (P<.01) or MMS (P<.04). However, diversity increased in this group after OLT, as measured by SE (P<.03) or MMS (P<.02). FS at 1 year after OLT correlated with transmission changes, as measured by SE (r=0.642, P<.0001) and MMS (r=0.443, P<.04), and with post-OLT changes (for SE: r=-0.583, P<.01; for MMS: r=-0.536, P<.01).

CONCLUSIONS

HCV complexity and diversity in the E2 region correlated with the severity of recurrence of HCV infection after OLT. Increased diversity of quasi species at transmission correlated with a higher FS at 1 year. However, increased diversity of quasi species in the post-OLT period correlated with a lower FS at 1 year. The dynamics of HCV quasi species in patients who undergo transplantation are predictive of outcome.

Immunocytochemical Study on Endothelial Integrity of Saphenous Vein Grafts Harvested by Minimally Invasive Surgery with the Use of Vascular Mayo Stripers. A Randomized Controlled Trial

OBJECTIVES

The aim of this study is to compare the endothelial integrity of saphenous vein grafts harvested by minimally invasive surgery and veins harvested conventionally for coronary artery bypass surgery in 200 participants who were assigned to interventions by using random allocation.

DESIGN

Randomized controlled trial. Methods. Immunocytochemistry with anti-CD 31 antibodies and anti-nitric oxide synthase (NOS) antibodies were employed to identify the endothelial integrity.

RESULTS

The CD 31 immunostaining showed that the endothelial cell integrity of the minimally invasive harvested veins was preserved in 82+/-13% of the circumference of luminal endothelium, while in conventionally harvested grafts it was reduced to 64+/-15% (p=0.05).> This was associated with the lack of CD 31 expression in vasa vasorum (10 and 18%) in both groups, respectively, (p=0.02). The NOS immunostaining revealed that the endothelial integrity of the minimally invasive harvested grafts was preserved in 96+/-4% of the luminal endothelium circumference as compared to 74+/-10% in conventionally harvested grafts (p=0.05). The percentage of cases with the lack of NOS expression in all vasa vasorum was 12 and 21%, in G1 and G2, respectively, (p=0.02).

CONCLUSION

The endothelial integrity of saphenous vein grafts harvested by minimally invasive surgery is better preserved than with the grafts obtained by the conventional manner. This could play an important role in improving vein graft patency rates.

Infection of primary human macrophages with hepatitis C virus in vitro: induction of tumour necrosis factor-alpha and interleukin 8

Hepatitis C virus (HCV) has been reported to replicate in monocytes/macrophages in infected patients. However, it is unclear whether macrophages are susceptible to infection in vitro and whether such an infection is consequential. Sera from 26 HCV-infected patients were incubated with primary human macrophages collected from healthy donors. Virus negative strand was detected by a Tth enzyme-based strand-specific assay and virus sequences were analysed by single strand conformation polymorphism (SSCP) and sequencing. Concentrations of the cytokines tumour necrosis factor-alpha (TNF-alpha) and interleukin (IL)-1beta, IL-6, IL-8, IL-10 and IL-12p70 were measured in culture supernatants and respective mRNAs were analysed in cell extracts by quantitative RT-PCR. For 15 sera, HCV RNA was detectable in 2- and 3-week cultures from at least one donor. Virus negative strand was detected in 29 % of macrophage samples in this group. In four cases, HCV RNA sequences amplified from macrophages differed from those amplified from sera suggesting evolution during infection. Concentrations of TNF-alpha and IL-8 were found to be significantly higher in supernatants from HCV-infected cultures. In conclusion, these preliminary data suggest that primary human macrophages are susceptible to HCV infection in vitro and this infection is associated with the induction of cytokines TNF-alpha and IL-8.

Acute renal failure: the new perspectives

This review updates the progress which has been made in the recent years in the field of diagnosis, prevention and treatment of acute renal failure (ARF). Despite the better recognition of the etiology and risk factors of ARF this disease is still characterized by high mortality especially when developing in patients with multi-organ failure. The origin of ARF is clearly multifactorial but its pathomechanism shows many similarities regardless of a cause. Due to the latest achievements in the understanding of the pathogenesis of ARF better preventive and therapeutic strategies are being developed. Some of them have been successfully tested in experimental settings. Surprisingly most of the human studies showed that preventive methods other than simple hydration could not change the course of the disease or even could be harmful. Also the critical issue remains early ARF detection. In turn in cases of fully developed acute tubular necrosis the major concern is to prevent secondary complications and organ failure and to introduce appropriate dialysis therapy. Although not yet supported by a significant reduction in mortality in most severe cases of ARF some progress has been made due to the development of new convective intermittent or continuous renal replacement therapies, notably hemodiafiltration.

Incident hepatitis C virus in women with human immunodeficiency virus infection

Individuals infected with human immunodeficiency virus type 1 (HIV-1) are frequently coinfected with hepatitis C virus (HCV). Acute HCV infection is often asymptomatic and poorly understood. We conducted a historical prospective study of HCV antibody and viremia in plasma samples obtained during 1994-1999 from a cohort of initially HIV-1-infected, HCV-uninfected women and from HIV-1-HCV-uninfected women. Twenty-two (1.5%) of 1517 experienced seroconversion. Of these, 14 (64%) truly acquired a new infection as assessed by enzyme immunoassay response and new-onset viremia. The incidence rate in HIV-1-infected women was 2.7 cases per 1000 person-years; it was 3.3 cases per 1000 person-years in HIV-1-seronegative women (relative risk, 1.21; P=.75). Acquisition of HCV was associated with any history of drug use (P<.01). Five of 12 viremic, seroconverting individuals cleared viremia. Incident HCV infection among HIV-1-infected and HIV-1-uninfected women was low. It was linked to drug use and commonly resolved.

Correlates of immune activation marker changes in human immunodeficiency virus (HIV)-seropositive and high-risk HIV-seronegative women who use illicit drugs

The majority of natural history studies of human immunodeficiency virus (HIV) infection have immune and viral parameters in men. Data demonstrating that women have lower HIV-1 RNA levels than men at the same CD4 cell counts have raised the question of immunologic differences in HIV-seropositive women. This study describes levels and changes in phenotypic markers of immune maturity, function, and activation in the CD4 and CD8 cell subsets in HIV-seropositive and high-risk HIV-seronegative women. Our primary hypothesis was that activation levels would be significantly higher among illicit drug users. However, results showed that HIV-1 RNA level was the strongest predictor of marker level and that both HIV-1 RNA level and CD4 cell count were independently associated with CD4 activation, but illicit drug use was not. In summary, this study demonstrated that immune activation was a significant pathogenic feature in women and that activation was driven by HIV infection and not illicit drug use.

Substance P--a potent risk factor in childhood lymphoblastic leukaemia

The study focused on determining the expression of substance P (SP) in neoplastic bone marrow cells in childhood acute lymphoblastic leukaemia (ALL) in terms of its mRNA and the level of protein production. An attempt has also been made to demonstrate a correlation of SP with leukaemia risk factors and treatment failure. The study group comprised 120 children treated for ALL. Expression of SP was examined by in situ hybridisation with a 5'-biotinylated probe and by immunocytochemistry with specific anti-human SP antibody. Out of 80 patients with common ALL, the expression of SP was demonstrated in 33 cases (41.2%). In the group of 24 children with pre-B ALL, the presence of SP was noted in six cases (25.0%). Of 16 patients with T-cell leukaemia, SP expression was demonstrated in 13 cases (81.2%). The percentage of immunopositive cells in the SP-positive cases ranged from 79.8 to 97.3. Treatment failure in the children with ALL was closely related to the expression of SP observed at the beginning of treatment. The results showed a connection between the presence of SP-positive blasts and leukaemia relapse. This may indicate that SP expression, involved in the proliferation of the tumour cells, may represent a novel risk factor in ALL.

Pituitary adenylate cyclase-activating polypeptide-immunoreactive (PACAP-IR) nerve fibers in the pig pineal gland

The present study demonstrates the occurrence of PACAP-immunoreactive (PACAP-IR) nerve fibers in different compartments of the pig pineal gland, including glandular capsule (where they form a very dense network) and subependymal tissue close to the pineal recess (moderate to dense meshwork of varicose fibers). Furthermore, several varicose fibers penetrate from the capsule into the connective tissue septa and then into the parenchyma, where they form unequally distributed, fine network and, in some cases, basket-like structures around pinealocytes. Some of the PACAP-IR nerve fibers, observed both in the habenular and posterior epithalamic areas, extend to the pineal gland. PACAP-IR cells could be demonstrated neither in the pineal gland, nor in epithalamic areas.

Distribution of NADPH-diaphorase activity in the pineal gland of the Turkey

NADPH-diaphorase activity was histochemically demonstrated in the nerve fibers, neuronal-like cell bodies and in the endothelial cells of the vasculature in the pineal gland of the turkey. The nerve fibers were localized in the choroid plexus, connecting the pineal gland with the diencephalon as well as inside the pineal gland, where they formed basket-like structures around the pineal follicles. A group of neuronal-like cell bodies was observed in the proximal part of the gland. The positive staining was not observed in the pinealocytes of rudimentary-photoreceptor type and in the supporting cells.

Detection and analysis of hepatitis C virus sequences in cerebrospinal fluid

Hepatitis C virus (HCV) sequences were detected in cerebrospinal fluid (CSF) in 8 of 13 HCV-positive patients. In four patients harboring different virus strains in serum and peripheral blood mononuclear cells (PBMC), CSF-derived virus was similar to that found in PBMC, which suggests that PBMC could carry HCV into the brain.

Carvedilol does not modulate moderate exercise-induced hyperkalemia in hemodialysis patients

BACKGROUND AND AIM

Non-selective beta-adrenergic blockers may cause hyperkalemia in patients with end-stage renal failure. In contrast, alpha-adrenergic blockade has been found to decrease the hyperkalemic effect of physical exercise in healthy subjects, although we were unable to confirm this effect in hemodialysis patients. In a crossover design, we studied the effect of carvedilol, a non-selective beta-adrenergic blocker with an additional alpha1-blocking activity, on exercise-induced hyperkalemia in 17 anuric hemodialysis patients.

METHODS

All subjects were given either carvedilol (25 mg/day) or placebo for 2 weeks in a random order with a 2-week wash-out period. At the end of each treatment period they underwent a 30-minute exercise test on a bicycle ergometer with a fixed load of 20 W.

RESULTS

The treatment with carvedilol caused a significant decrease in blood pressure. Serum potassium before exercise tests was similar (5.37 +/- 0.2 and 5.24 +/- 0.2 mmol/l on carvedilol and placebo, respectively; mean +/- SE). During the exercise, serum potassium increased significantly (p < 0.001 in both tests) and subsequently decreased during 30 minutes of recovery (p < 0.05). The mean rate of potassium increment during the exercise was similar (23.3 +/- 3.3 micromol/l/min on carvedilol and 20.0 +/- 3.6 micromol/l/min on placebo). During recovery, the mean rate of potassium decrement was 5.0 +/- 3.0 micromol/l/min and 6.7 +/- 2.7 micromol/l/min, respectively. Serum sodium, ionized calcium, insulin and plasma renin activity were similar before the exercise tests and did not change during the exercise.

CONCLUSION

Carvedilol does not enhance the hyperkalemic effect of moderate physical exercise in anuric hemodialysis patients.

Search for hepatitis C virus negative-strand RNA sequences and analysis of viral sequences in the central nervous system: evidence of replication

Patients with chronic hepatitis C are more likely to have significant changes in their physical and mental well-being than patients with liver disease of other etiology, and hepatitis C virus (HCV) has been occasionally implicated in diseases of the central nervous system. We analyzed the presence of the HCV negative-strand RNA sequence, which is the viral replicative intermediary, in autopsy brain tissue samples from six HCV-infected patients. Negative-strand HCV RNA was searched for by a strand-specific Tth-based reverse transcriptase PCR, and viral sequences amplified from brain tissue and serum were compared by single-strand conformational polymorphism analysis and direct sequencing. HCV RNA negative strands were detected in brain tissue in three patients. In two of these patients, serum- and brain-derived viral sequences were different and classified as belonging to different genotypes. In one of the latter patients, HCV RNA negative strands were detected in lymph node and, while being different from serum-derived sequences, were identical to those present in the brain. The results of the present study suggest that HCV can replicate in the central nervous system, probably in cells of the macrophage/monocyte lineage.