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Biomedical subjects

S Nakata

Publications and source records attributed to S Nakata.

At least 109 records · Page 6Linked to original sources
PubMed1998

Epidemiological study of prevalence of genogroup II human calicivirus (Mexico virus) infections in Japan and Southeast Asia as determined by enzyme-linked immunosorbent assays.

Mexico virus (MXV) is a genogroup II human calicivirus (HuCV). We conducted an epidemiological study to determine the prevalence of MXV infection in infants and adults in Japan and Southeast Asia by enzyme-linked immunosorbent assays (ELISAs) developed by using baculovirus-expressed recombinant MXV (rMXV) capsids. Of 155 stool specimens obtained from children younger than 10 years old with acute clinical gastroenteritis (diarrhea and vomiting) associated with small, round-structured viruses in Japan from 1987 to 1989, only 2 were positive for MXV antigen. In 42 outbreaks of acute gastroenteritis in Japan from 1986 to 1994, 1 in an infant home and 1 among adults were positive for MXV antigen. The pattern of acquisition of antibody to rMXV was different from that of acquisition of antibody to group A rotavirus, the prototype HuCV Sapporo virus, and Norwalk virus. The prevalence of antibody to rMXV remained low for the first 3 years of life, showed a steep rise during nursery school age, reaching a prevalence of 50%, and another steep rise during adolescence, reaching 80%; and steadily increased thereafter. A high prevalence of antibody (82 to 88%) was observed in adult populations in Japan and Southeast Asia, suggesting that MXV infection is common in these areas. The discrepancy between the high prevalence of antibody to MXV and a low rate of detection of MXV antigen may be explained by a high specificity of the antigen ELISA for the prototype and closely related MXV strains while serological responses can detect responses to a broader group of viruses.

Adult↗
PubMed1998

Relation between coronary blood flow and left ventricular mass in hypertension: noninvasive quantification of coronary blood flow by thallium-201 myocardial scintigraphy.

This study was conducted to quantify coronary blood flow (CBF) noninvasively according to the fractionation principle and to elucidate the relation between CBF and left ventricular hypertrophy. CBF/cardiac output (CO), estimated on the basis of the ratio of myocardial uptake/total injected dose of thallium-201 (% cardiac uptake), was determined in 14 control subjects and 40 patients with essential hypertension. CBF and CBF per 100 g of myocardium (unit CBF) were calculated according to the following formulas: CBF= % cardiac uptake x CO, and unit CBF = (CBF/LVM) X 100, where CO and left ventricular mass (LVM) are echocardiographically determined. There was good reproducibility of % cardiac uptake (r = 0.983, p < 0.0001). Percent cardiac uptake was greater in hypertensive patients (4.65+/-1.44%) than in control subjects (3.64+/-0.64%), and there was a positive correlation between % cardiac uptake and LVM. CBF (ml/min) was greater in hypertensive patients (240.7+/-80.5) than in control subjects (194.9+/-36.9), but unit CBF (ml/min/100 g) was less in hypertensive patients (102.2+/-26.7) than in control subjects (150.3+/-30.5). Multiple regression analyses showed that LVM was the most potent independent predictor of resting CBF in hypertension. Our results indicate that CBF, determined by thallium-201 myocardial scintigraphy, increases parallel to the increase in LVM, but unit CBF decreases even in the resting condition in patients with essential hypertension.

Adult↗
PubMed1998

Significance of measurement of prostate specific antigen (PSA) in familial prostate cancer lines.

The concentration of prostate specific antigen (PSA) in serum was measured in 20 brothers or sons in 10 families in which the father and son or brothers had prostate cancer using the E test TOSOH IIPA. The patients were between 32 and 70 years old with a mean age of 48.2 years. The PSA value was between 0.4 and 19.5 ng/ml with a mean value of 3.4 ng/ml. Five patients (25%) had PSA values exceeding the cut-off value of 4.0 ng/ml. After obtaining their consent, systematic prostate needle biopsy by transrectal ultrasonography was performed on 3 patients (15%). Prostate cancer was detected in all of them. Among them 2 patients were brothers, and since the other two brothers already had prostate cancer, all four brothers were confirmed to have prostate cancer. This is the first report of a familial prostate cancer in four brothers in Japan. In the western countries where the incidence of prostate cancer is higher than that in Japan, studies have been performed on the risk factors. Family history is one of the most important risk factors. In Japan, the incidence of prostate cancer is increasing rapidly. Moreover, patients with a prostate cancer family history are expected to increase. In such cases, prostate cancer screening should be performed aggressively from a young age.

Adult↗
PubMed1998

[PSA-doubling time immediately before the diagnosis of prostate cancer].

PSA-doubling time (PSA-DT) immediately before the diagnosis of prostate cancer was calculated in 8 prostate cancer patients in whom PSA was checked three or more times with the same kit during a period of 6 months or more. The correlation between PSA-DT and clinical stage or pathological differentiation was analyzed. In most patients, PSA correlated well showing a straight regression line to the observation period on a hemi-logarithmic scale. The correlation coefficient was high, almost 0.9 or more except in one patient. PSA-DT ranged from 5.1 to 64.9 months, averaging 23.1 months. There was no significant correlation between clinical stage or pathological differentiation and PSA-DT. However, PSA-DT in stage D patients tended to be shorter than that of stage B + C patients. One patient who had stage D poorly differentiated carcinoma died of cancer recurrence. In this patient, PSA-DT was short (5.1 months).

Adenocarcinoma↗
PubMed1998

[Three-dimensional gadolinium-enhanced dynamic MRI of whole liver using spectrally selected enhanced fast gradient recall sequence].

Three-dimensional gadolinium-enhanced dynamic MRI of whole liver using the spectrally selected enhanced fast gradient recall sequence (spec IR-efgre3d) was performed in five patients with HCC. Ten HCC nodules were confirmed by CTA, CTAP and Lipiodol CT, and all of them were detected with dynamic MRI. MIP images reconstructed from 3D gadolinium-enhanced dynamic MR studies clearly showed the main portal vein and its branches in all cases. Portal vein thrombosis was also demonstrated with the MIP images.

Carcinoma, Hepatocellular↗
PubMed1998

[Continuous intraportal chemotherapy for prevention of metachronous hepatic metastasis in colorectal cancer].

Fifty-five colorectal cancer patients who had continuous intraportal chemotherapy between 1990 and 1993 (treated group) and 130 colorectal cancer patients who did not have portal chemotherapy between 1982 and 1993 (untreated group) were studied to clarify the effects of continuous intraportal chemotherapy on the prognosis. After a catheter was placed in the portal vein through the right gastroepiploic vein at the time of radical operation, 10 mg of MMC was continuously infused for 4 hours at operation and 500 mg/day of 5-FU was continuously infused for 7 days postoperatively. The toxicities of this therapy were not serious. The five-year survival rate was 65.3% in the treated group and 65.6% in the untreated group. The five-year disease-free survival rate was 69.8% in the treated group and 58.6% in the untreated group, with no significant difference. In stage II patients, however, the five-year disease-free survival rate in the treated group was slightly higher than in the untreated group (90.0% vs 70.3%, p = 0.073), and the rate of hepatic recurrence in the treated group was significantly lower than in the untreated group. These results suggest that continuous intraportal chemotherapy may prevent metachronous hepatic metastases in stage II colorectal cancer patients.

Aged↗
PubMed1998

Clinical significance of the increased multidrug resistance-associated protein (MRP) gene expression in patients with primary breast cancer.

The efficacy of cancer treatment is limited by either intrinsic or acquired resistance to various chemotherapeutic agents. To evaluate the clinically important factors related to prognosis in primary breast cancer retrospectively, we investigated the expression of the following genes involving acquirement of drug resistance: multidrug resistance 1 (MDRl), multidrug resistance-associated protein (MRP), and topoisomerase (Topo) I, II alpha, and II beta. Using an RT-PCR method, we semiquantified the gene expression level in untreated stage II breast cancer tissue (n = 27) and noncancerous breast tissue (n = 10). Among the 27 cancer patients, who were all treated by adjuvant chemoendocrine therapy after surgery, 10 patients showed relapse within the following 10 years whereas 17 patients did not. The gene expression levels of MDRl, MRP, and Topo I, II alpha, and II beta were normalized to the level of the beta 2-microglobulin RT-PCR product. MRP mRNA expression was detected in 70% of the breast cancer tissues and its expression levels were significantly increased in the cancer group compared with the noncancerous breast tissues. Furthermore, the MRP level was much higher in the relapsed patient group. On the other hand, there were no significant differences in the MDRl mRNA levels between the noncancerous and cancer groups. Although Topo II alpha mRNA was not detected in noncancerous breast tissues, it was detected in 52% of the breast cancer tissues. In cancer patients, no significant difference in Topo II alpha mRNA levels was observed between the relapsed and nonrelapsed groups. These findings suggest that MRP might be used as one of the markers for poor prognosis in patients with breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

[Clinical study on prostate cancer initially presenting with disseminated intravascular coagulation syndrome].

We experienced five patients with prostate cancer with disseminated intravascular coagulation syndrome (DIC) at the first presentation at Gunma University Hospital and affiliated institutions between 1991 and 1997. Their average age was 68 years, average DIC score at the first presentation was 10 and prostate specific antigen (PSA) level was more than 700 ng/ml. All of them had multiple bone metastases. The therapy for DIC and hormonal therapy for prostate cancer were simultaneously started at the first presentation before prostate needle biopsy, but all patients died. The average number of days from the start of DIC to death was 685 days. The patients initially showed a good response to therapy, but their conditions soon aggravated. The prognosis was extremely poor, but some proper therapies lead to the prognosis which was equal to that of prostate cancer in Stage D2 without DIC.

Adenocarcinoma↗
PubMed1998

[Prostate specific antigen doubling time in prostate cancer before treatment and in refractory status].

Prostate-specific antigen(PSA) increases exponentially in prostate cancer patients before treatment and in refractory status. PSA increases in 68-86% of prostate cancer patients before treatment, and that of the remaining 14-32% of the patients is stable. Those patients with a higher pre-treatment PSA level are more likely to have a shorter PSA-doubling time(PSA-DT). The relationship between pre-treatment stage, grade and PSA-DT is controversial. PSA-DT in biochemical failure patients predicts the risk of clinical recurrence. PSA-DT was correlated well with time to clinical recurrence after biochemical failure. Distant recurrence was associated with short PSA-DT. Higher clinical stage and lower differentiation before treatment correlated with shorter PSA-DT in recurrent cancer patients. PSA-DT is an important parameter for judging malignant potential of each cancer.

Biomarkers, Tumor↗
PubMed1998

[Evaluation of transition zone biopsy in systematic prostate biopsy].

We evaluated the systematic biopsies performed on 83 patients suspected of having prostate cancer. In the systematic biopsy, 6 cores were from the peripheral zone and 2 cores from the transition zone. Cancer was detected in 25 patients (30.1%). The percentage of patients who had abnormal digital rectal examination and transrectal echo findings, average PSA and PSA density, and the number of examinations which suggested cancer were higher in the cancer group than in the non-cancer group, although the mean prostate volume was smaller. Cancer was more frequently detected in the peripheral zone than in the transition zone. Cancer was detected only in the transition zone in only 1 of the 25 cancer patients. We conclude that biopsy of the transition zone to all the patients is not always needed in systematic biopsy.

Aged↗
PubMed1998

Effects of plasmapheresis in a rabbit model of cancer cachexia.

We developed a model of cancer cachexia by transplanting VX2 tumors into rabbits and investigated the effects of plasmapheresis in this model. AIS activity was identified in supernatants obtained from VX2 tumor by phenyl Sepharose chromatography. Fractions eluted with 0.5 M NaCl showed the ability to damage the red blood cell membrane and suppress immunity. Rabbits exhibited marked weight loss, anemia and immunodeficiency 40 days after transplantation of VX2 tumors. Plasmapheresis inhibited plasma-induced damage of the red blood cell membrane and suppression of immunity. Twice-weekly plasmapheresis resulted in gradual normalization of cellular immunity. Weight loss and survival were also improved. No side effects were observed.

Animals↗
PubMed1997

Donor-specific tolerance by perioperative intrathymic injection of bone marrow cells in the rat cardiac allograft model: use of FK506 can shorten the necessary duration of pretransplant intrathymic conditioning.

BACKGROUND: Many strategies of tolerance induction by intrathymic (IT) injection of donor alloantigens have been reported to date; however, the timing of IT injection is usually 1-3 weeks before transplantation. METHODS: To apply IT injection to cadaveric organ transplantation, 1 x 10(8) fully allogeneic bone marrow cells (BMC) of Buffalo (BUF; RT1b) rats were intrathymically injected into Wistar Furth (WF; RT1u) rats at the time of BUF cardiac allografting with short-course therapy of antilymphocyte serum (ALS) and FK506 in our experimental model. RESULTS: Allogeneic IT injection of BUF BMC with ALS and FK506 indefinitely prolonged graft survival (mean survival time > 210 days) in all WF rats. On day 130 after grafting, tolerant WF rats accepted donor BUF skin grafts (> 120 days) but not third-party Lewis skin grafts. In control groups, syngeneic IT injection of WF BMC or intravenous injection of donor BUF BMC in combination with ALS/FK506 therapy failed to induce tolerance. In vivo testing was performed during induction (1 month) or during maintenance (6 months of tolerance. In the mixed lymphocyte reaction (MLR), spleen T cells of tolerant rats at 1 month after grafting displayed hyporesponsiveness after stimulation with donor cells. The addition of interleukin (IL)-2 to MLR culture did not restore T-cell responsiveness. Tolerant rats had a significantly decreased frequency of T cytotoxic cell precursors (fTcp) of 1:4,926, and frequency of IL-2-producing T helper cell precursors (fThp) of 1:23,925, compared with naive rats (1: 2,158 and 1:4,266, respectively). By 6 months after grafting, however, the anti-donor MLR proliferative responses of tolerant rats had been restored to the levels of naive splenic T cells. These tolerant rats displayed restoration of the (fTcp) of 1:2,842 and of the (fThp) of 1:5,630, which were comparable frequencies of naive rats. Suppressor T cells did not contribute in this model. In cardiac grafts of tolerant rats induced by IT injection, expression of both Th1 (interferon-gamma and IL-2) and Th2 (IL-4 and IL-10) cytokines was detected in the early phase; thereafter, expression was completely inhibited, except for interferon-gamma in the chronic phase. CONCLUSIONS: Perfect donor-specific tolerance was obtained by IT injection of donor BMC at the time of transplantation, while alloimmune responses were maintained at levels similar to those of naive rats.

Adoptive Transfer↗
PubMed1997

Germline mutations of the APC gene in two Japanese adenomatous polyposis patients.

Germline mutations of the adenomatous polyposis coli (APC) gene have been reported in patients with familial adenomatous polyposis (FAP) and are believed to be an early event in colorectal carcinoma. We report the results of screening for germline mutations of the APC gene in 4 cases of 2 kindreds using non-radioactive PCR-SSCP (polymerase chain reaction-single strand conformation polymorphism) analysis. The mutation in kindred 1 was a 4 bp deletion at codon 849 in exon 15, resulting in a frameshift leading to truncation of the APC gene product. In kindred 2, a transversion of C to G at codon 2038 was observed, resulting in an amino acid change from leucine to valine. In this case, it is possible to screen presymptomatic diagnosis easily and quickly by digestion with restriction enzyme EcoNI.

Adenomatous Polyposis Coli↗
PubMed1997

Quantitative analysis of myocardial ischemia by technetium-99m sestamibi exercise scintigraphy: a new method for change rate mapping.

In order to quantitatively assess the extent and severity of myocardial ischemia by Tc-99m sestamibi exercise myocardial scintigraphy, we developed a new method of change rate (CR) mapping and examined its efficiency. CR was calculated to divide the counts per pixel in the stress polar map by that in the rest polar map at each corresponding pixel. The CR map showed the CR values at each pixel. To correct the differences between the stress and rest images for the dose of Tc-99m sestamibi administered, the mean counts per pixel in the stress polar map and the rest map were adjusted to the same level. Regarding the regions in which the CR value was less than 1 as ischemia, we compared the abilities of the CR map and the polar map to detect coronary artery stenosis in 5 patients with angina pectoris. The sensitivity for coronary artery stenosis was 80% in the CR map, and 40% in the polar map. The specificity for both was 75%. We concluded that the CR map was effective in assessing the extent and severity of myocardial ischemia in Tc-99m sestamibi exercise myocardial scintigraphy.

Adult↗
PubMed1997

Molecular characterization of morphologically typical human calicivirus Sapporo.

Human calicivirus Sapporo (SV) has typical calicivirus morphology and causes acute gastroenteritis in children. The nucleotide sequence of 3.2 kb of the 3' end of SV was determined from a cloned cDNA. The 3' end of the SV genome is predicted to encode the RNA-dependent RNA polymerase region, the capsid protein and two small open reading frames. The nonstructural and capsid protein coding sequences in the SV genome are fused in a single open reading frame. The organization of these proteins in the SV sequence is similar to that of rabbit hemorrhagic disease virus and the recently described Manchester virus, and distinct from the genome organization of the prototype human calicivirus, Norwalk virus, that lacks typical calicivirus morphology and has been described as a small round structured virus (SRSV). Sequence analysis of the predicted capsid region showed that the SV capsid is longer by approximately 30 amino acids than the capsid of any of the SRSVs, and multiple sequence alignments showed that these additional amino acids are located in the variable region of the capsid protein. Expression of the capsid protein of SV in insect cells resulted in the self-assembly of virus-like particles that have a morphology similar to that of the native virus. This result shows that calicivirus morphology is determined by the primary sequence of the capsid protein.

Amino Acid Sequence↗
PubMed1997

Sapporo-like human caliciviruses are genetically and antigenically diverse.

The Sapporo-like human caliciviruses (HuCVs) comprise one of three genogroups of HuCVs associated with acute gastroenteritis. Phylogenetic analysis has shown that Sapporo-like HuCVs are related more closely to animal caliciviruses than to other known HuCVs. We produced 3.2 kb cDNA fragments from the 3' end to three Sapporo-like HuCVs that were associated with acute gastroenteritis in children (Houston/86, Houston/90, and London/92). Sequence analysis of the 3.2 kb cDNAs showed that two of the three viruses had a genomic organization similar to that of other Sapporo-like strains and the third strain (London/92) lacked an open reading frame overlapping the 5' end of the capsid gene. Alignment of the capsid sequences of these three strains showed 44-78% amino acid identity among the three strains. Phylogenetic analysis of the aligned sequences indicated the three strains are related but each belongs to a distinct genetic cluster. The genetic differences are associated with antigenic differences in that an enzyme immune assay (EIA) specific for the prototype Sapporo/82 strain detected the Houston/86 strain, but not the Houston/90 and London/92 strains. In vitro transcription and translation of viral cDNA containing the predicted capsid gene of Houston/90 resulted in a protein of 63 K, which is immunoprecipitated by sera from children infected with the strain. Genetically and antigenically distinct strains in the Sapporo-like HuCVs have not been described previously and the occurrence of such diverse strains in the same community likely increases the importance of these strains as a cause of illness in children.

Amino Acid Sequence↗