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Biomedical subjects

S Kakumu

Publications and source records attributed to S Kakumu.

At least 73 records · Page 4Linked to original sources
PubMed1996

Serial analysis of hepatitis B virus core nucleotide sequence of patients with acute exacerbation during chronic infection.

Recent studies suggest that hepatitis B virus (HBV) core region could be an immunological target and that amino acid (aa) substitutions are mostly restricted to a small segment located in the middle of the core region. We sequenced the middle portion of HBV core gene during the course of acute exacerbation of chronic hepatitis B, and compared aa variations between the region including ideal HLA-A2 binding motifs and the nonbinding region. Five HBeAg+ chronic hepatitis patients with subtype adr (three with HLA-A2 and two without HLA-A2) were selected and using polymerase chain reaction (PCR) and cloning system, the central part of core region (nt 2063 to 2365, 303 bp) was sequenced in sera from each patient at three time points; before, at the peak of, and after exacerbation of hepatitis. The second set of sera showed higher aa substitution rates in five and in three out of five patients compared with those of the first and third sera, respectively. No significant difference was found in the aa substitution rates for the region with ideal HLA-A2 binding motifs between patients with and without HLA-A2. In asymptomatic HBV carriers with persistently normal aminotransferase values, alterations of the aa sequence were not observed within the same time frame. The results suggest that aa substitutions often occur at some particular positions in the middle of HBV core region during acute exacerbation of the disease under possible host immune pressures. Furthermore, unidentified epitopes appear to exist in the central part of HBV core region and HLA-unrestricted lymphocytes may play a role in the immune response of chronic HBV carriers.

Adult↗
PubMed1996

Hypervariable region sequence in cryoglobulin-associated hepatitis C virus in sera of patients with chronic hepatitis C: relationship to antibody response against hypervariable region genome.

Essential mixed cryoglobulinemia is frequently associated with hepatitis C virus (HCV) infection, with the formation of HCV antigen/antibody complexes. The hypervariable region (HVR) of the HCV E2/NS1 region is thought to include epitopes for neutralizing antibodies, but it remains uncertain whether cryoglobulins (CGs) contain such antibody-bound HCV. Thus, we studied HVR clones isolated from cryoprecipitate and supernatant in the sera of four chronic hepatitis C patients with cryoglobulinemia, and expressed as fusion proteins with glutathione S-transferase (GST). Patients' sera were tested for antibody binding to the proteins. The rate of anti-HVR antibody-positive clones was significantly higher in cryoprecipitate (89% +/- 13%, P < .05) than in supernatant (41% +/- 25%). Both HCV RNA and anti-HVR antibody were more concentrated in cryoprecipitates compared with those of serum and supernatant in two patients tested. Anti-HVR antibody-positive clones in cryoprecipitate showed common amino acid (aa) sequences in each of the four patients. Similarly, all the antibody-positive clones in supernatant showed the same aa sequences for three of the four patients. When aa sequences were compared with those of reported isolates with genotype 1b, the mean percentage of aa difference was greater in the clones from supernatant and in anti-HVR antibody-negative clones than in the clones from cryoprecipitate and in the antibody-positive clones, respectively. These findings indicate that serum CG contains anti-HVR antibody-bound HCV in patients with chronic hepatitis C. Anti-HVR antibody-free individual clones, which were more frequently noted in supernatant, showed closely related sequences, but which were of a heterogeneous quasispecies nature.

Adult↗
PubMed1996

Deficiency of antibody response to hypervariable region of hepatitis C virus in patients with chronic hepatitis C.

BACKGROUND/AIMS: Frequent mutations in the hypervariable region of hepatitis C virus have been suggested to be a cause of persistent infection by providing a way for the virus to escape host immunity. However, the variation rate in the hypervariable region is often low in patients with chronic hepatitis. The aim of this study was to elucidate the mechanism of persistent infection in patients with chronic hepatitis by investigating the relationship between the antibody response to and the variation in hypervariable region. METHODS: The hypervariable regions of 26 clones of six patients with chronic hepatitis C were expressed as proteins fused with glutathione S-transferase, and sera of the patients were serially tested for antibody to these proteins. RESULTS: The extent of antibody response to the hypervariable region differed considerably among the patients. Three patients showed no or only scanty antibody response. These had a lower variation rate in the hypervariable region (0-1.3/year) than in the others with frequent or persistent antibody response (2.1-14.6/year). In two patients, serum samples were found to be reactive with the clones even before the appearance of the clones. In three patients, coexistence of the antibodies and corresponding clones were noted. An augmentation of antibody response always followed rises in serum alanine aminotransferase levels. CONCLUSION: Deficiency of antibody response to the hypervariable region may be one of the causes of persistency in hepatitis C virus infection.

Adult↗
PubMed1996

Sequence analysis of hypervariable region of hepatitis C virus (HCV) associated with immune complex in patients with chronic HCV infection.

Immune complex (IC) frequently exists in sera of patients with hepatitis C virus (HCV) infection. When circulating HCV particles are fractionated by differential flotation ultracentrifugation, HCV in the bottom fraction appears to be in the form of IC. Flotation ultracentrifugation of serum was done in 7 patients positive for serum anti-C3d-binding circulating IC and in 7 negative patients. In all IC-positive patients, HCV RNA was detected in the bottom fraction but not in the top fraction of 3 patients. Amino acid sequences of hypervariable region (HVR) of HCV in the bottom fraction of IC-positive patients were almost the same as those of whole serum, while those of the top fraction considerably differed from those of whole serum except for 1 case. These data suggest that the major population of HCV forms IC in IC-positive patients, and antibody response to the HVR of HCV is responsible for IC formation.

Aged↗
PubMed1996

[Two cases of metastatic lung cancer examined by bronchoscopic cytology].

We herein report two cases of metastatic lung cancer examined with bronchoscopic cytology. The first case involved a 43-year-old female, who had undergone low anterior resection of the rectum for rectal cancer three years earlier. Routine chest X-ray showed a nodular lesion in the left upper area. Bronchoscopic examination revealed a mass occluding the left upper bronchus. Simultaneous bronchoscopic biopsy and washing cytology were performed. The cytological specimen consisted of cell clusters with tall columnar epithelium arranged in a palisading manner. The cytological findings strongly suggested metastatic adenocarcinoma originating from the colorectal region. The patient died from respiratory failure. Autopsy confirmed metastatic deposit of adenocarcinoma in the lung. Histologically, the tumor invaded the overlying bronchial wall and was exposed in the lumen. The second case was an 80-year-old female, who had been diagnosed as gastric cancer by the endoscopic examination one year earlier. She had refused surgical treatment. Routine chest X-ray showed reticulonodular lesions disseminated throughout the bilateral lungs. Bronchial endoscopy presented edematous mucosa of the right lower bronchus. Brushing cytology as well as punch biopsy were taken. Cytological examination revealed atypical cells with increased N/C ratio and reduced cohesiveness. The lesion was diagnosed as metastatic adenocarcinoma of gastric origin from cytological findings and clinical history. The patient died from respiratory failure. Postmortem examination revealed cancer cells in the lymphatic channels of the bronchial wall. Our two cases indicate that bronchoscopic cytology is useful for estimating the origin of metastatic cancer.

Adenocarcinoma↗
PubMed1995

Genotype distribution in Nagoya and new genotype (genotype 3a) in Japanese patients with hepatitis C virus.

We evaluated hepatitis C virus (HCV) genotype distribution among Japanese patients in the city of Nagoya and the possible existence of any other genotype not determined by Okamoto's method. Eighty-five of 93 (91.4%) anti-HCV-positive patients had detectable HCV RNA. The genotype of the HCV isolate was determined in 84 of 85 (98.8%) of these HCV RNA-positive patients by Okamoto's method but determination was not possible in one (1.2%). Genotype 1b was detected in 58 of the 85 patients (68.2%), genotype 2a in 20 (23.5%), genotype 2b in 3 (3.5%), and genotype 1b + 2a in 3 (3.5%). In the remaining 1 patient in whom the genotype could not be determined, we determined the nucleotide sequence of the core region in HCV RNA extracted from this patient and evaluated it by molecular evolutionary analysis. This HCV isolate was then classified as genotype 3a. These results suggest that genotype 3a is rare among Japanese patients with HCV; thus, when classifying Japanese isolates, we should take more care because genotype 3a is not determined by current typing systems.

Amino Acid Sequence↗
PubMed1995

Serum HCV RNA titer at the end of interferon therapy predicts the long-term outcome of treatment.

BACKGROUND/AIMS: Serum HCV RNA was quantitated by the competitive polymerase chain reaction before, at the end of, and after interferon therapy. We assessed whether serum HCV RNA titer at the end of interferon therapy predicts the long-term outcome of treatment. METHODS/RESULTS: Of 71 patients treated with various doses of interferons, 21 became negative for HCV RNA persistently during follow up of 2 years, and they were considered as complete responders. The serial determinations of HCV RNA titer for each individual showed that in patients with HCV RNA negative at the end of therapy, the complete response rate was quite high (78.6%), while in patients with HCV RNA titer > or = 10(4) copies/ml at the end of therapy, none became complete responders in long-term follow up. The percentage decreasing to < or = 10(2) copies/ml of HCV RNA at termination of interferon tended to be higher in patients with genotype 2a (14/21, 66.7%) than in those with genotype 1b (18/42, 42.9%). The complete response rate of patients whose viral load was < or = 10(2) copies/ml at termination of interferon was significantly higher in genotype 2a (11/14, 78.6%) than in genotype 1b (5/18, 27.8%) (p < 0.01). Pretreatment HCV RNA titer appeared to correlate to the titer at the end of therapy (r = 0.596, p < 0.001); even when HCV RNA decreased to < or = 10(2) copies/ml, the higher pretreatment titer indicated a lower likelihood of complete response (p < 0.05). CONCLUSIONS: These results indicate that HCV genotype and pretreatment viral titer are important factors in the response to interferon therapy. In addition, our study suggests that it is possible to stop interferon therapy at an appropriate time by monitoring HCV RNA titer.

Adult↗
PubMed1995

Interferon gamma production by peripheral blood lymphocytes to hepatitis C virus core protein in chronic hepatitis C infection.

Evidence suggests that cellular immunity to hepatitis C virus (HCV) core protein may be important in the pathogenesis of viral infection. Therefore, interferon gamma (IFN-gamma) production by peripheral blood mononuclear cells (PBMC) derived from patients with chronic HCV infection (genotype 1b) was examined. The cellular immune response was evaluated with a recombinant HCV core fusion protein derived from a patient with genotype 1b. To identify the immunodominant epitopes, IFN-gamma production in responders was also assessed with a panel of nine synthetic peptides that covered the entire core region. It was found that mononuclear cells from 24 (52%) of 46 patients with chronic liver disease responded to the core protein; asymptomatic HCV carriers demonstrated a lower response rate (14%, P < .05). More important, individuals who had received IFN-alpha treatment and went into clinical and virological remission had a higher response rate (75%, P < .05) compared with those with ongoing hepatitis whose treatment failed (31%). Of 25 patients whose mononuclear cells responded to HCV core protein, 18 had a significant response to one or more peptides; 12 patients reacted to a peptide mixture containing hydrophilic sequences. The core peptide amino acid sequence 141 to 160 was recognized in 9 patients. Interestingly, 7 of 8 patients bearing HLA DR 4 and w53 haplotypes recognized the peptide sequence 141 to 160. Thus, IFN-gamma production of the mononuclear cell response appeared to be HLA DR restricted, and the responding cells were identified as CD4+ T cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Predictive factors in the response to interferon therapy in chronic hepatitis C.

Factors predicting the efficacy of interferon therapy were statistically analyzed on 111 patients with chronic hepatitis C. Of the treated patients (total doses of interferon; 96-468 MU), 35 (31.5%) had a long-term remission. On multivariate analysis, hepatitis C virus genotype (p < 0.0001), histological diagnosis (p < 0.05), fibrosis score of histological activity index (p < 0.01) and source of infection (p < 0.05) were found useful for predicting the response to interferon therapy. Our findings suggest that the outcome of interferon therapy can be predicted to some degree from pretreatment data, and that a new therapeutic strategy is necessary for the group of patients who are predicted to be nonresponders.

Adult↗
PubMed1995

Role of transforming growth factor beta 1 on hepatic regeneration and apoptosis in liver diseases.

AIMS: To investigate the effects of transforming growth factor beta 1 (TGF-beta 1) on regeneration and induction of apoptosis of liver cell and bile duct in various liver diseases. METHODS: Formalin fixed paraffin wax sections of 18 liver tissue samples were obtained by needle biopsy, surgery, or necropsy; these included six liver cirrhosis, three obstructive jaundice; five fulminant hepatitis, one subacute hepatitis, and three normal liver. Expression of TGF-beta 1, apoptosis related Le(y) antigen, Fas antigen, a receptor for tumour necrosis factor, and biotin nick end labelling with terminal deoxynucleotidyl transferase mediated dUTP (TUNEL) for locating DNA fragmentation, was investigated histochemically. RESULTS: TGF-beta 1 was expressed in areas of atypical bile duct proliferation, where bile duct continuously proliferated from liver cells. In occlusive jaundice and fulminant hepatitis, TUNEL was positive in nuclei and cytoplasm of metaplastic cells which formed incomplete bile ducts, and these cells appeared to extend from TGF-beta 1 expressing liver cells. Fas antigen was found only on the cell membrane of proliferated bile duct in fulminant hepatitis, which differed from TGF-beta 1 and TUNEL positive areas. Le(y) antigen was expressed in liver cell and bile duct at the areas with atypical bile duct proliferation, but its coexpression with TUNEL was rare. CONCLUSIONS: TGF-beta 1 plays a role in the arrest of liver cell regeneration and atypical bile duct proliferation, and in areas of rapidly progressing atypical bile duct proliferation, such as in fulminant hepatitis or bile retention. Apoptosis appears to be induced by TGF-beta 1. This phenomenon may account for the inadequate hepatic regeneration that occurs with liver disease.

Apoptosis↗
PubMed1995

Clinical evaluation of intramuscular administration of natural interferon-gamma in the treatment of chronic hepatitis B.

Natural interferon-gamma at a dose of 0.5 x 10(6) or 1 x 10(6) IU daily was intramuscularly administered daily for 4 weeks to 15 patients with chronic hepatitis B. The efficacy and safety of the treatment were evaluated for 24 weeks following the completion of the 4-week treatment period. Persistent disappearance of HBeAg was observed in 5 of 15 patients. Serum hepatitis B virus (HBV)-related DNA polymerase disappeared in 5 of 13 patients at the end of interferon therapy. On the other hand, serum ALT and beta 2-microglobulin levels showed a significant increase during the interferon therapy period. The side effects were completely reversible. These findings suggest that interferon-gamma has an antiviral effect in patients with chronic hepatitis B and that the main mechanism of the therapeutic effect may be associated with the elimination of HBV-infected hepatocytes due to the immunopotentiating effect of the substance.

Adult↗
PubMed1995

Serum cryoglobulin and chronic hepatitis C virus disease among Japanese patients.

OBJECTIVES: Hepatitis C virus (HCV)-associated mixed cryoglobulins appear to be detected often in hepatitis C-related chronic liver disease. The association of the two phenomenon among Japanese patients is the subject of the present study. METHODS: Serum levels of total hemolytic complement (CH50) and anti-C3d-binding immune complex, as well as the prevalence of cryoglobulins, were studied in 213 patients with chronic liver disease (hepatitis C, 155; hepatitis B, 58). Cryoprecipitates were tested for anti-HCV Ab and HCV RNA. RESULTS: CH50 activity was significantly lower in patients with hepatitis C than in those with hepatitis B except in responders to interferon who showed a sustained loss of HCV RNA. Cryoglobulins were detected in 24 (37%) of 65 patients with hepatitis C; they generally consisted of polyclonal immunoglobulins but one case. Cryoglobulins were more frequently observed in cirrhotic patients and in those with a longer duration of disease. Cryoglobulinemia-related clinical signs such as vasculitis occurred in only three cases. Patients with cryoglobulins had lower CH50 activity and higher immune complex values than those without cryoglobulins. Anti-HCV Ab and HCV RNA were detected in all cryoprecipitates tested. CONCLUSIONS: These findings suggest that HCV is a major cause of cryoglobulins and advanced liver damage. However, serum cryoglobulins with polyclonal immunoglobulins appear to be less frequent among Japanese patients than among those studied in Western countries.

Adult↗
PubMed1994

Hepatitis C virus genotypes are not responsible for development of serious liver disease.

Although hepatitis C virus (HCV) is known to have at least four kinds of genotypes, no clear relationship has yet been established between the genotype and the severity of liver disease. Therefore, we determined HCV genotypes in sera of 251 Japanese patients with type C chronic liver disease, using polymerase chain reactions with six independent primers. One set of primers and a probe derived from 5'-noncoding region of HC-J1 was supposed to detect all four genotypes, while the other five were devised to detect each of the genotypes. Among the patients, the major genotype was type II (69%) and the second most common was type III (18%). Type IV was found in 7%, while none had type I genotype. There was no significant difference in the distribution of any genotype among different stages of liver disease, although the ratio of type II to type III tended to be higher in the group of cirrhosis and hepatocellular carcinoma than in the chronic hepatitis group (5.5 vs 3.0). The amounts of HCV RNA were significantly greater in patients with type II (P < 0.001) compared with those with types III and IV. However, HCV concentrations of each genotype were not associated with the disease status. These results suggest that HCV genotypes are unlikely to be responsible for the development of more serious liver disease.

Adult↗
PubMed1994

Changes in serum hepatitis C virus RNA titer and response to interferon therapy in patients with chronic hepatitis C.

Response to interferon (IFN) therapy for chronic hepatitis C has been determined by the alteration of serum alanine aminotransferase (ALT) values. However, eradication of hepatitis C virus (HCV) could be another aim of the therapy. Thus, we serially measured serum HCV RNA levels during therapy and for at least 12 months after cessation of therapy in 65 patients with chronic hepatitis C who received IFN-alpha (49 cases) or -beta (16 cases). The presence of HCV and its amount were measured by the combination of nested and competitive PCR. Twenty-seven patients, who were categorized as complete responders, showed sustained normalization of ALT values for more than six months posttreatment. The viral RNA titers at pretreatment were significantly lower in complete responders (logarithmic copy numbers/ml: 5.4 +/- 1.3, P < 0.001) than in partial and nonresponders. Complete response rate was significantly higher in patients with HCV genotype III (68.4%, P < 0.01) than those with type II (23.6%). Among 27 complete responders, HCV RNA became undetectable in only 13 patients six months after completion of therapy, and 11 still had low levels of viremia; however, none experienced relapse of the disease during follow-up of 12-24 months. Three complete responders showed lasting high-titered viremia, and their ALT values rose again during follow-up. Our data suggest that IFN treatment of chronic hepatitis C is often ineffective in eradicating HCV infection even in responders, and long-term follow-up study is necessary to determine the sustained beneficial effect of IFN.

Adult↗