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Biomedical subjects

H Katano

Publications and source records attributed to H Katano.

At least 37 records · Page 2Linked to original sources
PubMed2001

Effective human herpesvirus 8 infection of human umbilical vein endothelial cells by cell-mediated transmission.

Cell-free transmission of human herpesvirus 8 (HHV-8) to human cells in vitro has been reported to be difficult, if not impossible. The present experiments were conducted with the idea that cell-cell contact may produce much more effective transmission, so-called cell-mediated transmission. Primary human umbilical vein endothelial cells (HUVECs) were cocultured with an HHV-8-infected lymphoma cell line, BCBL-1 cells. When a ratio of 12-O-tetradecanoylphorbol-13-acetate (TPA)-treated BCBL-1 cells to HUVECs of 10:1 was used, more than 20% of HUVECs were found to express the HHV-8 latency-associated nuclear antigen (LANA) 48 h after the start of coculturing; this value increased to more than 30% after 72 h. HHV-8-encoded ORF26, K8, K8.1, K10, K11, ORF59, and ORF65 proteins were not detected in these HHV-8-infected HUVECs until 72 h. The HHV-8 antigens were not observed in HUVECs cocultured with TPA-treated BCBL-1 cells separated by a membrane. Thirty days after removal of the BCBL-1 cells from the cell-mediated transmission experiment, the HUVECs still expressed LANA and the HHV-8 genome was detected by PCR in these cells. Moreover, the ORF59 protein, a DNA replication-associated protein of HHV-8, was expressed in such HUVECs in the presence of TPA stimulation. These results indicated a far more effective transmission mechanism, cell-cell contact, suggesting the possibility that such a mechanism works in vivo.

Cell Communication↗
PubMed2001

Ion-transfer voltammetry of local anesthetics at an organic solvent/water interface and pharmacological activity vs. ion partition coefficient relationship.

The ion-transfer reaction of local anesthetics at an organic solvent/water interface has been studied using cyclic voltammetry (CV) with a stationary nitrobenzene (NB)/water (W) interface. Procaine and seven other local anesthetics gave reversible or quasi-reversible voltammograms at the NB/W interface in the pH range between 0.9 and 9.6. These drugs are present in aqueous solution in either neutral or ionic form, or both forms. The half-wave potential, as determined by the midpoint potential in CV, vs. pH curves, were determined and analyzed to determine the partition coefficients of both neutral and ionic forms of the drugs between NB and W. The partition coefficients of the ionic forms were derived from their formal potential of transfer at an NB/W interface. The dissociation constants of ionic forms of the drugs in NB were also deduced. A high correlation between the pharmacological activity and the partition coefficient of the ionic form of amide-linked local anesthetics has been shown.

Algorithms↗
PubMed2001

Effects of aging on the electroretinogram during ischemia-reperfusion in rats.

The effects of aging on the electroretinogram (ERG) during ischemia-reperfusion were investigated in rats. Flash-elicited ERG (a-wave, b-wave, and oscillatory potentials (OPs)) was recorded in young (4 months old) and aged rats (over 18 months old) before, during, and after exposure to 30- or 120-min ischemia induced by increasing intraocular pressure to 80 mmHg. The choroidal blood flow, measured by means of laser Doppler flowmetry, decreased to 40 to 60% of the baseline value during ischemia. Young rats showed no significant difference in the amplitude of each ERG component during ischemia between 30- and 120-min ischemia groups; 78.0 +/- 4.9 vs. 76.1 +/- 3.6% for a-wave, 63.4 +/- 3.1 vs. 60.6 +/- 3.0% for b-wave, and 59.6 +/- 5.9 vs. 57.5 +/- 6.7% for SigmaOP. In aged rats, however, 120-min ischemia caused a greater decrease, to 56.7 +/- 3.1% of the baseline value, in the a-wave amplitude than 30-min ischemia did, to 70.8 +/- 3.2%. The reduction of each ERG component in both 30- and 120-min ischemia experiments was greater in aged rats than in young rats. The recovery time for the amplitude of each ERG component during reperfusion was longer in aged rats than in young rats. The latency of b-wave and the second component of OPs prolonged during ischemia, and recovery time for the latency was longer in aged rats than in young rats. These results suggest that the electrophysiological function of the retina is less tolerable against ischemia-reperfusion in aged rats than in young rats.

Aging↗
PubMed2000

p53-independent transient p21(WAF1/CIP1) mRNA induction in the rat brain following experimental traumatic injury.

The expression of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) mRNA after traumatic brain injury in rats was investigated using an in situ hybridization technique, along with regulating gene p53 and stress response gene hsp70 mRNA levels. At 3 h postinjury, p21(WAF1/CIP1) mRNA was markedly increased in the cortex, white matter, thalamus, CA2, a part of CA1,3 and dentate gyrus of the injured side. Hybridization signals remained elevated at 6 h in injured cortex and hippocampus and returned to the baseline by 24 h post-insult. On the other hand, p53 mRNA induction was not observed in any brain sections throughout the post-injury time course. Slight expression of hsp70 mRNA was detected in the injured cortex 3-6 h following injury and this was similar to the temporary pattern of p21(WAF1/CIP1) mRNA expression. This study showed p21(WAF1/CIP1) mRNA to be transiently induced after traumatic brain injury, independent of p53, this possibly being an early stress response to protect cells by arresting them in the cycle and allow DNA repair.

Animals↗
PubMed2000

Expression and localization of human herpesvirus 8-encoded proteins in primary effusion lymphoma, Kaposi's sarcoma, and multicentric Castleman's disease.

To investigate the expression of human herpesvirus 8 (HHV8)-encoded proteins in the cells of primary effusion lymphoma (PEL), Kaposi's sarcoma (KS) and multicentric Castleman's disease (MCD), nine rabbit polyclonal antibodies to K2, ORF26, K8, K8.1, K10, K11, ORF59, ORF65, and ORF73 were developed. Western blot analysis in PEL cell lines (TY-1 and BCBL-1) revealed that the expression of these proteins, except ORF73 (LANA), was induced by tetradecanoylphorbol acetate (TPA) treatment, indicating that these proteins are lytic proteins. Immunofluorescence assay in primary PEL cells derived from pericardial effusion and PEL cell lines with and without TPA treatment revealed that primary PEL cells exhibited the same expression pattern as noninduced PEL cell lines, and the treatment changed localization of K8, ORF59, and ORF65 proteins. Immunohistochemistry revealed that 90% of KS spindle cells expressed the ORF73 protein, whereas a small population of KS cells expressed K8, K10, K11, ORF59, and ORF65 proteins. In MCD, ORF73, ORF59, K8, K2, and K10 proteins were expressed in the cells at mantle zone of the follicle. These data indicate that KS and PEL cells expressed predominantly latent proteins, whereas MCD expressed both latent and lytic proteins, suggesting that HHV8 plays a different role in the pathogenesis of HHV8-associated diseases.

Animals↗
PubMed2000

Human herpesvirus 8-associated solid lymphomas that occur in AIDS patients take anaplastic large cell morphology.

Human herpesvirus type 8 (HHV-8; Kaposi's sarcoma-associated herpesvirus) is a recently isolated human herpesvirus frequently identified in Kaposi's sarcoma, primary effusion lymphoma, and multicentric Castleman's disease. Here we report three cases of HHV-8-bearing solid lymphomas that occurred in AIDS patients (Cases 1-3). All three patients were homosexual men presenting extranodal masses in the lungs (Case 1) or skin (Cases 2 and 3), together with the presence of Kaposi's sarcoma (Case 1), primary effusion lymphoma (Case 2), or multicentric Castleman's disease (Case 3). These solid lymphomas exhibited anaplastic large cell morphology and expressed CD30, corresponding to the recent diagnostic criteria of anaplastic large cell lymphoma (ALCL). The chromosomal translocation t(2;5)-associated chimeric protein p80NPM/ALK was not observed in any of these cases. HHV-8 was detected in all of these cases by polymerase chain reaction, immunohistochemistry of HHV-8-encoded ORF73 protein, and in situ hybridization of T1.1. Epstein-Barr virus was detected only in Cases 2 and 3 by in situ hybridization. It is interesting that inoculation of a cell line obtained from a primary effusion lymphoma cell in Case 2 to severe combined immunodeficiency mice produced HHV-8-positive and Epstein-Barr virus-negative tumors in inoculated sites. These tumor cells exhibited phenotypes of ALCL that were identical to the subcutaneous tumor cells of this particular patient. These findings clearly show that HHV-8 can associate with solid lymphomas and that it can take anaplastic large cell morphology. Those lymphomas should be distinguished from the classical ALCL as were defined by the revised European-American classification of lymphoid neoplasms even though morphology and a part of immunophenotype mimic that of classical ALCL.

Adult↗
PubMed2000

Spontaneously regressed Kaposi's sarcoma and human herpesvirus 8 infection in a human immunodeficiency virus-negative patient.

Kaposi's sarcoma occurring in a 78-year-old woman, with the absence of the human immunodeficiency virus infection, was correctly diagnosed by immunohistochemistry using anti-human herpesvirus 8 (HHV8) antibody (PA1-73N) for the first time. The patient suffered from chronic respiratory failure and was treated with a low dose of steroids for 2.5 years. After her medication dosage was increased for the exacerbation of the respiratory failure, multiple skin tumors in her feet and legs suddenly developed. Histopathologically, skin tumors were suspected as Kaposi's sarcoma at the first biopsy and reactive angiomatosis at the second biopsy. Polymerase chain reaction and immunohistochemistry, however, revealed the presence of HHV8 DNA fragment and positive staining in the majority of spindle cells in the skin tumors. Serological examination confirmed the positivity of anti-HHV8 antibodies. HHV8 infection and steroid-induced immunosuppression, as well as environmental factors played a role in the development of Kaposi's sarcoma in this patient, because she was born in Okinawa, which is a well-known endemic area of Kaposi's sarcoma in Japan. As her general condition improved, the skin lesions regressed without any specific treatment, and disappeared completely 8 months later, in which regression may be associated with evidence of numerous CD8 cell infiltration in the second biopsy tissues. No recurrence was observed during the following 6 month follow up.

Aged↗
PubMed2000

Hypothermia modulates induction of hsp70 and c-jun mRNA in the rat brain after subarachnoid hemorrhage.

We investigated expression of hsp70 and c-jun mRNA with in situ hybridization for evaluating hypothermia effect on the brain exposed to subarachnoid hemorrhage (SAH). SAH was induced in Wistar rats with endovascular perforation. Animals were divided arbitrarily into normothermic and hypothermic groups, and they were sacrificed at 3 h or 12 h after SAH. The SAH induced hsp70 and c-jun mRNAs in the cerebral cortex, hippocampus, thalamus, hypothalamus, and caudoputamen. Mild hypothermia depressed hsp70 mRNA expression in the cortex, thalamus, and hippocampus. The c-jun mRNA expression was reduced by hypothermia in the cortex, thalamus, and CA1 of the hippocampus. Based on these findings, we speculate that hypothermia protects the brain exposed to SAH by reducing this stress response. Although it is yet difficult to employ hypothermia in the clinical settings, this study suggests its utility to those patients sustaining severe subarachnoid hemorrhage.

Animals↗
PubMed2000

Identification of antigenic proteins encoded by human herpesvirus 8 and seroprevalence in the general population and among patients with and without Kaposi's sarcoma.

To establish a sensitive and specific antibody assay, potent antigenic proteins encoded by human herpesvirus 8 (HHV8) were studied. Fifteen recombinant HHV8-encoded proteins were produced as glutathione S-transferase fusion proteins. The sera from AIDS-associated Kaposi's sarcoma (KS) patients reacted with four proteins encoded by open reading frames (ORFs) K8.1, 59, 65, and 73 in a Western blot assay. An enzyme-linked immunosorbent assay (ELISA) using these four proteins as antigens (mixed-antigen ELISA) revealed that all 26 sera derived from KS patients (24 with and 2 without human immunodeficiency virus infection) became positive for anti-HHV8 antibodies. The presence of HHV8 was demonstrated in 14 (1. 4%) of 1,004 sera from the Japanese general population and 10 (1.9%) of 527 sera from patients without HHV8-associated diseases. The presence of immunoglobulin G (IgG) and IgM antibodies against HHV8 examined further by the mixed-antigen ELISA and Western blotting revealed IgG antibody in all ELISA-positive sera, while IgM antibody against ORF K8.1 was absent. These data suggest that the ORF 73 and 65 proteins are potent antigens for a sensitive serological assay.

AIDS-Related Opportunistic Infections↗
PubMed2000

Human herpesvirus 8 virology, epidemiology and related diseases.

Human herpesvirus 8 ([HHV-8], Kaposi's sarcoma-associated herpesvirus [KSHV]) is a novel human oncovirus classified as a gamma-herpesvirus. HHV-8 is associated with Kaposi's sarcoma (KS), primary effusion lymphoma (PEL) and some cases of multicentric Castleman's disease (MCD). Antibodies against HHV-8 are detected in the sera of almost all KS patients, about 30% of HIV-infected homosexual males in the world and 1.4% of the Japanese population. In HHV-8-associated malignancies such as KS and PEL, HHV-8 latently infects these tumor cells. Unlike other viruses, HHV-8 encodes several human homologues including cytokines (IL-6, MIPs, IRFs) and regulatory proteins (cyclin D, G-protein coupled receptor [GPCR]). These proteins may play significant roles in the pathogenesis of HHV-8-associated diseases. It has been demonstrated in vitro that the functions of retinoblastoma and p53 proteins were inhibited by viral cyclin D and latency-associated nuclear antigen, respectively. Mice transgenic for GPCR have a KS-like region in the skin. These data suggest the full oncogenecity of HHV-8. On the other hand, many cells expressing lytic proteins are found in MCD tissues, suggesting that the pathogenesis of MCD is different from that of HHV-8-associated malignancies.

Castleman Disease↗
PubMed1999

Traumatic injury in vitro induces IEG mRNAs in cultured glial cells, suppressed by co-culture with neurons.

Glial changes following traumatic injury to glial monolayers as well as to neuronal-glial co-culture systems in vitro were examined with a focus on the expression of mRNAs coding for the immediate early genes (IEG) c-fos, c-jun and zif/268, demonstrated using in situ hybridization. Glial cells along scratch wound lines extended cytoplasmic processes as early as 10 min post-injury and the whole wound was covered with gliosis by 24 h. For complete restoration in the case of glial cells co-cultured with neurons, this required 48 h. Induction of the three IEG mRNAs was eminent along the edges of scratch wound, peaking at 30-60 min post-injury and subsiding by 3 h. The peak expression of IEG mRNAs was delayed to 1-3 h post-injury and became undetectable at 6 h in neuronal-glial co-cultures. The data suggest that mechanical injury to glial cells causes gliosis and the expression of IEG mRNAs, which are suppressed by co-culture with neurons, indicating some influence of neuronal-glial interactions.

Animals↗
PubMed1999

Seroprevalence of human herpesvirus 8 in human immunodeficiency virus 1-positive and human immunodeficiency virus 1-negative populations in Japan.

To determine the seroprevalence of human herpesvirus 8 (HHV8) among human immunodeficiency virus 1 (HIV-1)-positive (HIV-1+) and HIV-1-negative (HIV-1-) populations in Japan, 276 HIV-1+ patients and 1,000 HIV-1- blood donors were enrolled in this study. Antibodies against HHV8 latency-associated nuclear antigen (LANA) were examined through indirect immunofluorescent assay by using a B-cell line that was infected latently with HHV8 (body cavity-based lymphoma 1). An HHV8- and Epstein-Barr virus-negative B-cell line (Ramos) was used as a control. Thirty-two seropositive cases against LANA (anti-LANA+) were identified among the 276 HIV-1+ patients who were studied. Five cases were foreigners living in Japan. The risk factor of all 27 Japanese cases was unprotected sexual intercourse, and the great majority of these cases (23 in 27; 85%) reported homosexual/bisexual behavior. Anti-LANA+ status correlated with the presence of sexually transmitted diseases, such as amoeba and HBV infection, further suggesting male homosexual behavior as the main route of HHV8 transmission in Japan. Only two LANA+ cases were identified among 1,000 HIV- blood donors in Japan; thus, seroprevalence of HHV8 identified by LANA was estimated to be 0.2% among HIV-1- populations in this country.

Adolescent↗
PubMed1999

Expression and antigenicity of human herpesvirus 8 encoded ORF59 protein in AIDS-associated Kaposi's sarcoma.

Human herpesvirus 8 (HHV-8, Kaposi's sarcoma-associated herpesvirus, KSHV) is a new herpes virus isolated from patients with AIDS-associated Kaposi's sarcoma (AIDS-KS). The ORF59 protein of HHV-8 has recently been shown to encode a processivity factor (PF-8) for HHV-8-encoded DNA polymerase. By immunoscreening a cDNA library derived from the HHV-8-infected cell line TY-1, ORF59 antigen was identified in AIDS-KS patients. Immunoblotting revealed that recombinant ORF59 protein reacted with sera from patients with AIDS-KS. Enzyme-linked immunosorbent assay (ELISA) using ORF59-recombinant protein as the antigen revealed that 7 of 22 (31. 8%) AIDS-KS patients and 6 of 263 (2.2%) Japanese HIV-negative patients or healthy blood donors were positive for anti-ORF59 antibodies. Immunohistochemistry using anti-ORF59 rabbit antibodies revealed that this protein was expressed in some of the tumor cells found in KS tissues and that ORF59 protein was detected in 11 of 22 (50%) AIDS-KS tissues. In situ hybridization indicated that some of KS tumor cells were positive for HHV-8 T1.1 mRNA in the same specimen. These data suggest that ORF59 is one of the HHV-8 encoded antigens in patients with AIDS-KS and also indicated that viral replication occurred in some of KS tumor cells.

AIDS-Related Opportunistic Infections↗
PubMed1999

High expression of HHV-8-encoded ORF73 protein in spindle-shaped cells of Kaposi's sarcoma.

Human herpesvirus 8 (HHV-8) has been demonstrated previously in Kaposi's sarcoma (KS) tissues by immunohistochemistry, in situ polymerase chain reaction, and in situ hybridization. The HHV-8-encoded protein ORF73 is a 222- or 234-kd protein named latent nuclear antigen (LNA) or latency-associated nuclear antigen (LANA) that is identified in HHV-8-infected cell lines by immunofluorescence assay. In the present study, a rabbit antibody against a recombinant ORF73 protein was developed. Immunofluorescent staining of a HHV-8-infected cell line, TY-1, showed that the staining pattern of the anti-ORF73 antibody overlapped completely the LANA staining pattern obtained using KS patients' sera. Immunoblotting analysis showed that the anti-ORF73 antibody reacted specifically with 222- and 234-kd proteins that were present in TY-1 and BCBL-1 cell lysates. Immunohistochemistry using a catalyzed signal amplification system demonstrated that the anti-ORF73 antibody reacted exclusively with the majority of KS spindle-shaped cells, showing a nuclear dot-like staining pattern. Some of the ORF73 protein-positive cells also expressed CD34 and vimentin but not CD68 or factor-VIII-related antigen. These data indicate that the anti-ORF73 antibody recognizes LANA and that most KS cells are infected with HHV-8 in the latent phase. Our findings also suggest that ORF73 protein plays an important role in the pathogenesis of KS.

Animals↗