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M Pardo

Publications and source records attributed to M Pardo.

At least 37 records · Page 2Linked to original sources
PubMed2000

A proteomic approach for the study of Saccharomyces cerevisiae cell wall biogenesis.

In fungi, cell shape is determined by the presence of a rigid cell wall which separates the cell from the extracellular medium. This highly dynamic structure is essential for the maintenance of cell integrity and is involved in several phenomena such as flocculation, adherence and pathogenicity. The composition of the fungal cell wall is well known, but issues such as the assembly and remodeling of its components remain poorly understood. In an attempt to study the de novo construction of the yeast cell wall, we have undertaken a large-scale proteomic approach to analyze the proteins secreted by regenerating protoplasts. Upon incubation of protoplasts in regenerating conditions, numerous proteins are secreted into the culture medium. These presumably include proteins destined for the cell wall, comprising both structural proteins as well as enzymes involved in cell wall biogenesis. This work reports the establishment of a reference map of proteins secreted by regenerating protoplasts by means of two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) and their identification by mass spectrometry. Thirty-two different proteins have been identified, including known cell wall proteins, glycolytic enzymes, heat shock proteins, and proteins involved in several other processes. Using this approach, novel proteins possibly involved in cell wall construction have also been identified. This reference map will allow comparative analyses to be carried out on a selected collection of mutants affected in the cell wall.

Amino Acid Sequence↗
PubMed2000

Pilot study of combination therapy with ribavirin and interferon alfa for the retreatment of chronic hepatitis B e antibody-positive patients.

Twenty-four patients with chronic hepatitis B virus (HBV), antibody to hepatitis B e antigen (anti-HBe), HBV DNA positivity, and alanine transaminase (ALT) elevation who failed previous interferon alfa (IFN-alpha) therapy were included in a pilot study of combination therapy with ribavirin and IFN-alpha. The patients received daily oral ribavirin (1,000-1,200 mg according to body weight) plus 5 million units (MU) IFN-alpha2b three times a week for 12 months and were followed-up for 12 months. The median viremia level decreased significantly at the end of treatment (1.2 x 10(3) copies/mL) and follow-up (4.0 x 10(2) copies/mL) compared with the baseline (3.0 x 10(6) copies/mL; P <.05). After 12 months, 8 of 24 (33%) patients had cleared HBV DNA and 12 (50%) had normal ALT levels. At the end of the study virological and biochemical response was 50% and 21%, respectively. Thus, virological and biochemical response sustained in 5 of 24 (21%) patients retreated with ribavirin and IFN-alpha; none of them lost hepatitis B surface antigen (HBsAg). Liver histology improved in 2 of 4 sustained responders but in none of the 12 nonresponders with paired biopsies (P =.05). The response was independent of dose and duration of previous treatment, viral load, or the distribution of HBV precore wild-type/mutant variants. However, sustained responders had significantly higher necroinflammation (P =.036) and fibrosis (P =.007) scores. IFN-alpha-related side effects were mild and reversible on discontinuation. In 4 (17%) patients who suffered nausea and diarrhea the ribavirin dosage was reduced by 50% after 1 month of therapy and finally discontinued in all of them. No patient had liver disease decompensation. In summary, combination therapy with ribavirin and IFN-alpha may be efficacious to treat viremic anti-HBe-positive patients with chronic hepatitis B who have failed previous IFN therapy.

Adult↗
PubMed2000

Randomized controlled trial of recombinant human granulocyte-macrophage colony-stimulating factor for the treatment of chronic hepatitis c.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered subcutaneously to 45 chronic hepatitis C patients, randomly assigned to receive 0.5, 1 or 2 microg GM-CSF/kg b.w. daily/6 weeks (n=30), or no treatment (n=15). Alanine transaminase (ALT) values normalized in four out of 10 (40%) patients administered 2 microg GM-CSF [1 cleared hepatitis C virus (HCV) RNA] but in none given 0.5 or 1 microg or untreated controls (P=0.0079). Following 4 weeks of rest, patients received 5 million units of interferon (IFN)alpha2b every other day/6 months, alone (n=30), or combined with 2 microg GM-CSF/daily for 3 months (n=15). At treatment end, ALT levels in patients administered the combination normalized more frequently than in those given monotherapy (73% vs 47%, P=0.089). Viraemia decreased significantly in 11/15 (73%) patients administered GM-CSF/IFNalpha2b combination (mean log HCV RNA copies/ml+/-SEM: 4.13+/-0.40 vs 5.29+/-0.23;P=0.011), and in 20/30 (67%) receiving IFNalpha2b monotherapy (4.27+/-0.28 vs 5. 31+/-0.14;P=0.004); 27% and 20% of patients given the combination and monotherapy, respectively, cleared HCV RNA. One patient in each regime had a sustained response after 12 months. 2', 5'-Oligoadenylate synthetase activity (2-5AS) increased during GM-CSF therapy (P=0.033 with the 2 microg dose). 2-5AS increased more in the GM-CSF/IFN-alpha2b combination than with IFNalpha2b monotherapy (P<0.02). GM-CSF provoked a skin reaction at the injection site, accompanied by moderate and reversible rises in eosinophil and leucocyte counts. In summary, daily s.c. GM-CSF administration is safe and shows effects against HCV; the GM-CSF/IFNalpha2b combination has an additional-but transient-antiviral activity in chronic hepatitis C.

Adolescent↗
PubMed2000

A phase I/II study of recombinant human interleukin-12 in patients with chronic hepatitis B.

BACKGROUND/AIMS: Interleukin-12 (IL-12) may be active against hepatitis B virus (HBV). The objective of the study was to assess the tolerability, activity, pharmacokinetics, and pharmacodynamics of three dose levels (0.03 microg/kg b.w., n=15; 0.25 microg/kg b.w., n=15; 0.50 microg/kg b.w., n=16) of recombinant human (rHu) IL-12 given s.c. once a week for 12 consecutive weeks. METHODS: Forty-six patients with chronic hepatitis B, HBV DNA positivity and aminotransferase elevation were included in a multicenter prospective randomized phase I/II study. RESULTS: Compared with the baseline, HBV DNA levels had decreased significantly at the end of rHuIL-12 treatment and after the 12-week follow-up period (p<0.001). The response to rHuIL-12 treatment was dose-dependent: at the end of the study HBV DNA clearance was greater in patients treated with 0.50 microg/kg b.w. (25%) or with 0.25 microg/kg b.w. (13%) compared with those given 0.03 microg/kg b.w. (7%). Moreover, HBeAg became undetectable at the end of follow-up in five of the patients given the 0.25microg/kg (2/15) or the 0.50 microg/kg (3/16) dose. The drug pharmacology showed that IL-12 had an estimated half-life of 30 h with levels remaining detectable for more than 48 h after rHuIL-12 administration. The serum levels of IL-12, interferon-gamma, IL-10, neopterin and beta2-microglobulin as well as the area under the curve (AUC) were rHuIL-12 dose-related. Side effects were observed more frequently with higher doses, including moderate decreases in lymphocyte and neutrophil counts; three patients withdrew prematurely from treatment. The local reaction observed at the injection site was unrelated to the drug dose. Only one patient showed detectable antibody levels to rHuIL-12 without clinical impact. CONCLUSIONS: Treatment with rHuIL-12 at the doses investigated is safe and tolerable, and appears to be active against HBV in patients with chronic hepatitis B.

Adjuvants, Immunologic↗
PubMed2000

Presence of TTV DNA in serum, liver and peripheral blood mononuclear cells from patients with chronic hepatitis.

The main site of TT virus (TTV) replication remains unknown. Therefore, we have studied the presence and titres of TTV DNA in paired serum, liver and PBMC samples from 50 patients with liver disease (32 with chronic hepatitis B or C, seven with cryptogenic hepatitis and 11 with nonviral liver disease) were included. TTV DNA was analysed by polymerase chain reaction (PCR) using primers from the open reading frame 1 (ORF 1) and from the untranslated region (UTR) and titres were semiquantified by PCR using an external standard. TTV DNA was detected in 26% of serum, 24% of liver and 14% of PBMC samples with ORF 1 primers. When UTR primers were used, 70% of serum and liver samples and 64% of PBMC were TTV DNA positive. No differences between TTV positive and negative patients were found regarding epidemiological or biochemical parameters. Trypsin treatment and fluorescent in situ hybridization confirm the intracellular location of TTV in PBMC. The mean of TTV DNA titres was statistically higher in liver than in serum or PBMC. TTV titres in serum correlated with those in PBMC but not with those in liver. In conclusion, although the liver seems to be the main site for TTV replication, this virus is also able to infect PBMC.

Adult↗
PubMed2000

Detection of hepatitis C virus replication by In situ hybridization in epithelial cells of anti-hepatitis C virus-positive patients with and without oral lichen planus.

Epidemiological studies have demonstrated that there is a correlation between oral lichen planus and chronic hepatitis C virus (HCV) infection. HCV RNA has been recently detected in epithelial cells from oral lichen planus lesions by reverse-transcription polymerase chain reaction (RT-PCR). However, this technique does not discriminate which types of cells are infected by the virus or if the viral RNA is present in the serum that contaminates the biopsy. Morphological evidence of viral replication in cells from these lesions is needed to establish a role for HCV in oral lichen planus. Consequently, we have analyzed the presence of positive and negative HCV-RNA strands in oral mucosa biopsies from 23 patients (14 anti-HCV-positive) diagnosed as having oral lichen planus and from 5 patients with chronic hepatitis C without oral lichen planus. Positive and negative HCV-RNA strands were detected in epithelial cells of the mucosa biopsies from all anti-HCV-positive patients independently of whether or not they had oral lichen planus, but in none of the anti-HCV-negative cases. The percentage of stained cells ranged from 4.4% to 14.3%. These percentages do not correlate with the serum viremia levels or the intensity of the cellular infiltrate in patients with oral lichen planus. In conclusion, we have shown that HCV replicates in epithelial cells of patients with and without oral lichen planus. The pathological consequences of this finding remain to be elucidated.

Adult↗
PubMed1999

Two-dimensional analysis of proteins secreted by Saccharomyces cerevisiae regenerating protoplasts: a novel approach to study the cell wall.

Protoplasts of Saccharomyces cerevisiae incubated in regenerating conditions secrete cell wall components in order to allow the biosynthesis of this structure. During the first hours of incubation, many of these are not retained in the forming cell wall but remain in the medium. We have developed a method for collecting the secreted proteins and have analysed these by two-dimensional electrophoresis to obtain a reference map of putative cell wall proteins. Several proteins were identified by microsequencing or immunoblotting; namely, cell wall hydrolytic enzymes, heat shock proteins, glycolytic enzymes and others. Some beta-1,3- and beta-1, 6-glucosylation was detected in the proteins secreted by regenerating protoplasts.

Amino Acid Sequence↗
PubMed1999

Modulation by biologic response modifiers of hepatitis C virus antigen-independent cytokine secretion in blood mononuclear cells.

The systemic hepatitis C virus (HCV) antigen-non-specific cytokine responses were investigated in cultures of peripheral blood mononuclear cells. Cytokines of the T helper (Th) 1 [interferon (IFN)gamma and interleukin (IL)-2] and Th2 (IL-4 and IL-10) phenotype, and the pro-inflammatory cytokines tumour necrosis factor alphaIL-1beta and IL-6, were secreted by the cells activated by the HCV antigen-independent pathway. Furthermore, these cytokine responses were shifted towards a Th1 predominance by treatment with IFN-beta and with IL-2, whereas cytokine responses were selectively amplified towards a combined Th1-Th2 profile by granulocyte-macrophage- but not by macrophage colony-stimulating factor. Moreover, pro-inflammatory cytokine production was significantly enhanced by IFN-beta and augmented dose-dependently with GM-CSF and IL-2. Therefore, these immune mediators can promote unique-as well as overlapping-systemic cytokine responses that may be relevant for immunotherapeutic interventions to control HCV infection.

Cells, Cultured↗
PubMed1999

Histological damage in chronic hepatitis C is not related to the extent of infection in the liver.

It has not been completely elucidated whether the liver injury induced by the hepatitis C virus (HCV) is due to direct cytopathic damage or to an immune-mediated response against HCV-infected hepatocytes. In this work, we have determined the percentage of HCV-infected hepatocytes, the histological activity index, and the viremia levels in chronically HCV-infected patients with different grades of liver injury to investigate any possible correlation between them. For that purpose, liver biopsies from 27 patients with HCV chronic hepatitis were analyzed by in situ hybridization. This technique revealed that the percentage of infected hepatocytes ranged from 0.04% to 83.6%. Regarding the viremia levels, HCV RNA concentration ranged from 1.8 x 10(3) to 1.4 x 10(6) genome copies/ml. A significant correlation (r = 0.54; P = 0.003) between the percentage of infected hepatocytes and the viremia levels was found. In contrast, no correlation was observed between the percentage of HCV-infected hepatocytes or the viremia levels and the histological activity index. In conclusion, we have shown that the HCV viremia reflects the extent of the infection in the liver and that the liver injury in chronic HCV infection is not directly related to either the number of infected hepatocytes or the serum HCV RNA concentration.

Biopsy↗
PubMed1999

In vitro effect of amantadine and interferon alpha-2a on hepatitis C virus markers in cultured peripheral blood mononuclear cells from hepatitis C virus-infected patients.

The effects of amantadine (1-5 microM) and interferon alpha (IFNalpha)-2a alone (1000 IU/ml) and combined, have been studied in cultured peripheral blood mononuclear cells (PBMC) from 15 chronic hepatitis C patients and ten healthy donors. Amantadine itself did not affect cell viability and had minor effects on the response to mitogens by PBMC. Four patients (27%), but no donors, had hepatitis C virus (HCV) core and NS3-specific proliferative responses. Amantadine suppressed these responses in all cases and its antiproliferative effect was greater than that of IFNalpha (Mann-Whitney's U-test: P < 0.05 in both cases). All PBMC cultures from patients, but none from donors, were HCV RNA positive. Amantadine alone or combined with IFNalpha dose-dependently reduced HCV RNA content in individual PBMC (Wilcoxon's signed rank test: 1 microM, P < 0.05; 2 microM, P < 0.02; and 5 microM, P = 0.16) with respect to untreated cultures. In addition, 7, 13 and 20% of PBMC cultures became HCV RNA negative with 2 microM amantadine alone, IFNalpha alone and their combination, respectively. Finally, in contrast to IFNalpha, amantadine did not modify expression of 2',5'-oligoadenylate synthetase activity or the spontaneous or mitogen-stimulated IFNgamma and interleukin 10 production. In conclusion, these effects in PBMC from HCV patients suggest that the amantadine/IFNalpha combination might be considered a therapeutic option for treating chronic hepatitis C patients.

2',5'-Oligoadenylate Synthetase↗
PubMed1999

In vivo and in vitro induction of MxA protein in peripheral blood mononuclear cells from patients chronically infected with hepatitis C virus.

To test whether (HCV) persistence is related to interferon (IFN) hyporesponsiveness, peripheral blood monuclear cells from 29 patients and 11 controls were studied for MxA protein expression. In vitro, only IFN-alpha (P<.001) and interleukin-2 (P<.05) induced MxA protein expression above unstimulated levels. Forty patients were treated with IFN-alpha2b. Patients showed higher basal levels of MxA protein (P<.02) and 2',5'-oligoadenylate synthase (2-5A) activity (P<.05) than controls. During therapy, MxA protein levels (P<.001) and 2-5A activity (P<.05) increased; after 1 month, MxA levels remained high, whereas 2-5A activity declined to initial levels. Increases in MxA were inversely correlated with decreases in serum alanine aminotransferase levels, and MxA induction was greater among virological responders. Thus, the IFN system seems to be activated in chronic HCV infection, but HCV appears to modulate these two components of the IFN system differentially. These results suggest that an inefficient response may contribute to virus persistence and affect the therapeutic outcome.

2',5'-Oligoadenylate Synthetase↗
PubMed1999

The efficacy and safety of clozapine versus chlorpromazine in geriatric schizophrenia.

BACKGROUND: There has been an absence of controlled studies focusing specifically on neuroleptic treatment in the elderly schizophrenic population. Therefore, we conducted a 12-week double-blind comparison study to assess the efficacy and tolerability of clozapine and chlorpromazine in a group of elderly inpatients with chronic schizophrenia. METHOD: Forty-two elderly DSM-IV schizophrenic veterans were randomly assigned to clozapine or chlorpromazine and assessed for efficacy at baseline and at termination with the Positive and Negative Syndrome Scale (PANSS) and the Clinical Global Impressions scale (CGI). Side effects were also monitored. Medications were titrated, on the basis of clinical response and side effects, to a maximum dose of 300 mg/day of clozapine or 600 mg/day of chlorpromazine. RESULTS: The results suggest that both the chlorpromazine and clozapine groups improved their PANSS scores at termination compared with baseline, but the difference between the 2 groups was not statistically significant. The mean CGI scores reflecting severity of illness also demonstrated improvement in both groups over time. Both groups had similar incidences of side effects. One patient in each group had a life-threatening side effect. More patients taking clozapine had tachycardia and weight gain, while more chlorpromazine patients noted sedation. CONCLUSION: We concluded that both clozapine and chlorpromazine are effective treatments for psychosis and behavioral disturbances in geriatric schizophrenia. Both agents had similar incidences of side effects. With careful monitoring and titration of dosage, both clozapine and chlorpromazine were fairly well tolerated in this population.

Age Factors↗
PubMed1998

Quantitation of hepatitis C virus in liver and peripheral blood mononuclear cells from patients with chronic hepatitis C virus infection.

Since the natural history of hepatitis C virus-associated liver disease and the therapeutic responsiveness might vary according to liver and blood mononuclear cells viral levels, it may be important to quantitate viral RNA in liver, blood mononuclear cells and serum, and to compare these data with genotype, biochemical and histologic data. A polymerase chain reaction-based assay available for serum hepatitis C virus RNA quantitation has been optimized to quantitate viral genomes in liver and peripheral blood mononuclear cells from 47 chronic hepatitis C patients. The procedure permitted hepatitis C virus RNA quantitation in freshly isolated mononuclear cells and in total RNA extracted from frozen mononuclear cells and liver tissue. The intrahepatic viral amount (median: 2.6 x 10(3) copies/microgram RNA; range: 0 to 3.6 x 10(4) copies/microgram RNA) correlated significantly with the hepatitis C virus RNA concentration in serum (r = 0.76, P < .001), but not in mononuclear cells. Viral RNA concentrations in liver (P < .001), serum (P < 0.01) and PBMC (P < 0.05) were significantly higher in hepatitis C virus genotype 1 patients (essentially type 1b) than in non-1 type cases, but were unrelated to biochemical or histologic indexes of disease activity. In conclusion, the optimized assay permit HCV RNA quantitation in liver and peripheral blood mononuclear cells, suggesting that serum viral level is an accurate measurement of intrahepatic viral burden.

Adult↗
PubMed1998

Effects of the ribavirin-interferon alpha combination on cultured peripheral blood mononuclear cells from chronic hepatitis C patients.

The effects of ribavirin and interferon (IFN) alpha have been investigated on cultured peripheral blood mononuclear cells, obtained from 15 patients with chronic hepatitis C virus (HCV) infection. At clinically relevant serum concentrations achieved during therapeutic administration, ribavirin did inhibit moderately the mitogen-stimulated mononuclear cell proliferation and growth of the CD4+ and CD8+ T cell subsets without apparent cytolysis. The ribavirin-IFN-alpha combination showed activity against HCV with disappearance of HCV RNA in 27% of cases, and a synergy in the inducibility of the intracellular enzyme 2',5'-oligoadenylate synthetase. Such ribavirin concentrations induced modest increases in the T helper 1-like cytokine production by mononuclear cells. Higher ribavirin concentrations markedly inhibited IFN-gamma production, but augmented interleukins (IL) 2, 4, and 12 secretion. Conversely, IFN-alpha tended to suppress IL 2, 4 and 12, but enhanced IFN-gamma and IL-10 secretion. Thus, ribavirin and IFN-alpha appear to cause diverse effects on immunoregulatory cytokine secretion, and when combined, counteracted for production of IL-2 and IL-12, while upregulated mononuclear cell secretion of IFN-gamma and that of the anti-inflammatory cytokine IL-10. These findings suggest a non-cytolytic modulation of inflammatory responses induced by the drug combination, that may be relevant in the pathophysiology of chronic HCV infection.

2',5'-Oligoadenylate Synthetase↗
PubMed1998

Pharmacokinetics, antifolate activity and tissue distribution of PT523 in SCC VII tumor-bearing mice.

PURPOSE: To monitor the pharmacokinetics of PT523 and methotrexate in C3H mice with transplanted SCC VII tumors; to compare the impact of PT523 and methotrexate on tumor and normal host 5,10-methylenetetrahydrofolate levels; and to synthesize [14C]PT523 and determine its time-dependent tissue distribution in tumor and host tissues. METHODS: C3H mice bearing SCC VII tumors were given i.p. PT523 or methotrexate. Plasma drug levels and tumor, gut and marrow 5,10-methylenetetrahydrofolate were assayed. [14C]PT523 was synthesized and administered i.v. to tumor-bearing mice for tissue distribution analysis. RESULTS: Areas under the curve, mean residence times, whole body clearances, apparent distribution volumes, and plasma protein binding of PT523 vs methotrexate were, respectively, 4311 vs 6472 microM x min(-1); 20 vs 16 min; 0.56 vs 0.36 ml min(-1); 532 vs 325 ml x kg(-1); and 70% vs 30%. Both PT523 and methotrexate caused time-dependent declines in 5,10-methylenetetrahydrofolate in tumor and marrow, but not in gut mucosa [corrected]. Gut levels began to recover within 4 h in the PT523-treated group only. [14C]PT523 distributed mainly into the liver, duodenum, kidneys, lungs, tumor, pancreas and muscle; less into the spleen, blood cells, heart, brain and testicles; and very little into gut [corrected. Only 35% of the dose was excreted, and 2.9-fold more in feces than urine. CONCLUSIONS: Despite its more rapid clearance, accumulation of PT523 in extravascular tissues was greater than that of methotrexate. Consequently, less PT523 was recovered in feces and urine and its apparent volume of distribution was greater. PT523 selectively depleted 5,10-methylenetetrahydrofolate pools in tumor and, less persistently, in marrow, but spared the gut mucosa [corrected]. [14C]PT523 tissue distribution correlated with organ mass and blood supply.

Animals↗