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Biomedical subjects

K Takada

Publications and source records attributed to K Takada.

At least 109 records · Page 6Linked to original sources
PubMed2000

A novel arterial infusion chemotherapy for the treatment of patients with advanced pancreatic carcinoma after vascular supply distribution via superselective embolization.

BACKGROUND: Patients with American Joint Committee on Cancer Stage IV advanced pancreatic carcinoma have been treated by systemic chemotherapy, intraarterial chemotherapy, radiation therapy, and multidisciplinary treatment using a combination of these. However, the outcome has not always been satisfactory. In the current study the authors describe the method and results of a new chemotherapy for advanced pancreatic carcinoma. METHODS: To restrict the blood flow into the pancreas (mainly to the great pancreatic artery and the caudal pancreatic artery), the peripancreatic blood vessels were embolized superselectively with microcoils. In 31 patients with advanced pancreatic carcinoma, the catheter tip for the arterial infusion chemotherapy was placed in the splenic artery just proximal to the branching of the great pancreatic artery when the treatment was given for primary tumors, and in the common hepatic artery when the treatment was given for a metastatic liver lesion. The other end of the catheter was connected to an implanted injection port embedded in the femoral region, and 5-fluorouracil and cisplatin were administered by continuous arterial infusion. RESULTS: Of the 31 patients with advanced pancreatic carcinoma, 23 (74%) underwent hemodynamic change and arterial infusion chemotherapy, with a response rate of 73.9% (complete response rate of 8.7% and a partial response rate of 65.2%) and a mean survival period of 18.26 +/- 10.06 months. The 1-year, 2-year, and 3-year survival rates were 90.9%, 42. 8%, and 18.3%, respectively, with a mean survival period of 19.0 months. Of these 23 patients, the 16 patients with liver metastases had a response rate of 68.8% and a mean survival period of 16.25 +/- 8.35 months, whereas the 7 patients without liver metastases had a response rate of 87.5% and a mean survival period of 22.86 +/- 12.69 months. CONCLUSIONS: In patients with Stage IV advanced pancreatic carcinoma, arterial infusion chemotherapy after hemodynamic change was found to be effective against both primary tumors and metastatic liver lesions. The authors believe that the treatment presented in the current study should be attempted, even in patients with advanced pancreatic carcinoma, as long as the blood vessels for vascular supply distribution exist.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Induction of apoptosis by extracellular ubiquitin in human hematopoietic cells: possible involvement of STAT3 degradation by proteasome pathway in interleukin 6-dependent hematopoietic cells.

The ubiquitin-proteasome pathway is responsible for selective degradation of short-lived cellular proteins and is critical for the regulation of many cellular processes. We previously showed that ubiquitin (Ub) secreted from hairy cell leukemia cells had inhibitory effects on clonogenic growth of normal hematopoietic progenitor cells. In this study, we examined the effects of exogenous Ub on the growth and survival of a series of human hematopoietic cells, including myeloid cell lines (HL-60 and U937), a B-cell line (Daudi), and T-cell lines (KT-3, MT-4, YTC-3, and MOLT-4). Exogenous Ub inhibited the growth of various hematopoietic cell lines tested, especially of KT-3 and HL-60 cells. The growth-suppressive effects of Ub on KT-3 and HL-60 cells were almost completely abrogated by the proteasome inhibitor PSI or MG132, suggesting the involvement of the proteasome pathway in this process. Furthermore, exogenous Ub evoked severe apoptosis of KT-3 and HL-60 cells through the activation of caspase-3. In interleukin-6 (IL-6)-dependent KT-3 cells, STAT3 was found to be conjugated by exogenous biotinylated Ub and to be degraded in a proteasome-dependent manner, whereas expression levels of STAT1, STAT5, or mitogen-activated protein kinase were not affected. Moreover, IL-6-induced the up-regulation of Bcl-2 and c-myc, and JunB was impaired in Ub-treated KT-3 cells, suggesting that the anti-apoptotic and mitogenic effects of IL-6 were disrupted by Ub. These results suggest that extracellular Ub was incorporated into hematopoietic cells and mediated their growth suppression and apoptosis through proteasome-dependent degradation of selective cellular proteins such as STAT3. (Blood. 2000;95:2577-2585)

Apoptosis↗
PubMed2000

PEBP2alphaA/CBFA1 mutations in Japanese cleidocranial dysplasia patients.

Cleidocranial dysplasia (CCD) is an autosomal dominant human bone disease whose genetic locus has been located on chromosome 6p21, where the PEBP2alphaA/CBFA1 gene essential for osteogenesis also maps. Previously, several heterozygous mutations in PEBP2alphaA/CBFA1 were found in CCD patients. In this study, we identified six different types of mutations in PEBP2alphaA/CBFA1 in Japanese CCD patients. Four cases were similar to those reported previously: two were nonsense mutations in the Runt domain, one was a hemizygous deletion, and the other was a missense mutation in the Runt domain which abolished the DNA-binding activity of Runx2/PEBP2alphaA/CBFA1. The remaining two mutations were novel: one had a heterozygous gt-to-tt mutation at the splice donor site (gt) between the exon3-intron junction, which resulted in abnormal exon3 skipping, and the other had a mutation in exon7, which led to the introduction of a translational stop codon in the middle of the transactivation domain. Thus, defects in either the DNA-binding domain or transactivation domain of Runx2/PEBP2alphaA/CBFA1 can cause CCD. The results not only provide a strong genetic evidence that mutations involving in PEBP2alphaA/CBFA1 contribute to CCD, but also provide a useful tool to study how Runx2/PEBP2alphaA/CBFA1 plays its pivotal role during osteoblastic differentiation.

Amino Acid Substitution↗
PubMed2000

Determination of 18alpha-glycyrrhizin and 18beta-glycyrrhizin in dog plasma by high-performance liquid chromatography.

A high-performance liquid chromatographic method has been developed for the separation and determination of 18alpha-glycyrrhizin (alpha-GZ) and 18beta-glycyrrhizin (beta-GZ) in dog plasma. The two compounds were separated on a reversed-phase column and detected by UV absorption at 254 nm. The mobile phase was a mixture of water-methanol-60% perchloric acid (45:55:0.5, v/v) and was adjusted to pH 8.0 with 25% ammonia solution. Indomethacin was added to the plasma as an internal standard. Methanol was selected for the extraction of both the compounds and internal standard. Alpha-GZ and beta-GZ could be precisely determined in concentration of 1 mg/ml in a 0.1 ml sample.

Ammonia↗
PubMed2000

Characteristics of intestinal absorption and disposition of glycyrrhizin in mice.

As basic studies to apply an intestinal pressure-controlled colon delivery capsule (PCDC) for glycyrrhizin (GZ), the characteristics of intestinal absorption and disposition of GZ were investigated in mice. In the in vivo study, after intravenous (iv) administration of GZ, 10 mg/kg dose, plasma GZ disappeared from the systemic circulation with t(1/2(alpha)) of 0.0063 h, thereafter, it slowly declined with t(1/2(beta)) of 15.23 h. The area under the plasma drug concentration versus time curve (AUC) values of iv (10 mg/kg), intracolonic (50 mg/kg) and intraduodenum (50 mg/kg) administrations were 115.1, 16.7 and 2.7 microgh/mL, respectively. The AUC values of plasma glycyrrhetic acid (GA), a degradation product after intracolonic and intraduodenum administrations were 2.8 and 8.4 microgh/mL, respectively. In the in situ closed loop study, the concentrations of GZ in plasma and liver after intracolonic administration were significantly increased (p<0.05) in comparison with those after intrajejunum or intraileum administration, while the concentration of GA in plasma and liver after intracolonic administration had trends to increase. These observations clearly suggest that the intracolonic administration is a useful way to improve the oral bioavailability of GZ and to enhance its pharmacological efficacy. These pharmacokinetic results of GZ suggest that GZ is a subject drug to be applied for the PCDC system we previously developed. The PCDCs formulation of GZ will enable us to carry GZ to the colon and enhance the oral bioavailability of GZ.

Animals↗
PubMed2000

Lytic Epstein-Barr virus infection in the synovial tissue of patients with rheumatoid arthritis.

OBJECTIVE: To evaluate the existence of Epstein-Barr virus (EBV) infection in the synovial tissue of patients with rheumatoid arthritis (RA). METHODS: Synovial tissues were obtained at synovectomy or arthroplasty from 32 patients with RA and 30 control patients with osteoarthritis (OA). EBV DNA was detected by Southern blot hybridization and/or polymerase chain reaction (PCR) amplification. To localize the EBV-infected cells, tissue sections were studied by RNA in situ hybridization (ISH) for the EBV-encoded small RNA 1 (EBER-1), by DNA ISH for the Bam HI W region of EBV DNA, and by immunohistochemistry for EBV lytic proteins BZLF1 and gp350/220. RESULTS: EBV DNA was detected by PCR in 15 of the 32 samples from RA patients (47%), but in none of those from the 30 OA patients (P < 0.01). Of the 15 PCR-positive samples, 9 contained >1 EBV copy/1,000 cells (referred to as EBV 2+), and 6 contained 1 copy/1,000-5,000 cells (EBV 1+). Among the 9 EBV 2+ samples, 3 were also positive for EBV DNA by Southern blot hybridization, 5 were positive for EBER-1 by RNA ISH, and 3 were positive for EBV DNA by DNA ISH. Immunohistochemical analysis showed positive signals in all samples for BZLF1 and in 7 samples for gp350/ 220. In each examination, the positive signals were detected not only in lymphocytes, but also in synovial lining cells. CONCLUSION: EBV was frequently detected in the synovial tissue of RA patients. The infected cells were both lymphocytes and synovial cells, and expressed EBV proteins associated with virus replication. These findings suggest that EBV may play a role in the pathogenesis of RA.

Adult↗
PubMed2000

Estrogen directly acts on osteoclasts via inhibition of inward rectifier K+ channels.

Using the whole-cell patch-clamp technique in freshly isolated rat osteoclasts we examined the effects of estrogen on ionic channels. The predominant current was an inward rectifier K+ current (IKir). In the absence of non-osteoclastic cells, extracellularly applied 17beta-estradiol (>0.1 microM) inhibited IKir, indicating that estrogen acts directly on osteoclasts. Application of 17beta-estradiol (10 microM) for 10 min reduced IKir at the membrane potential of -120 mV to 70 +/- 15% of control. Removal of 17beta-estradiol partially restored the inhibition. The inhibition of IKir was dependent on concentration and application time. Intracellularly applied 17beta-estradiol had no effect on IKir. 17alpha-estradiol also inhibited the IKir, whereas progesterone and testosterone had no effect. The inhibitory action of 17beta-estradiol was not affected by guanosine 5'-O-(2-thiodiphosphate) (GDPbetaS), adenosine 3',5'-cyclic monophosphothioate Rp diastereomer (Rp-cAMPS), okadaic acid, staurosporine and phorbol ester, and was independent of intracellular Ca2+ concentration ([Ca2+]i). With no influence from soluble factors secreted from non-osteoclastic cells, preincubation of the osteoclasts for more than 60 min with much lower concentrations of 17beta-estradiol (1 and 10 nM) caused a reduction of IKir. In current-clamp configuration, application of 17beta-estradiol (10 microM) depolarized the membrane associated with a decrease in a membrane conductance, indicating that 17beta-estradiol inhibits IKir and depolarizes the membrane of osteoclasts. These results suggest that the 17beta-estradiol-induced inhibition of IKir might be mediated via non-genomic mechanisms. This direct action of 17beta-estradiol on osteoclasts may contribute to the regulation of [Ca2+]i and partially account for the protective effects of estrogen against bone loss.

Animals↗
PubMed2000

Limited pancreatectomy: significance of postoperative maintenance of pancreatic exocrine function.

This study attempted to clarify whether limited pancreatectomy (duodenum-preserving total pancreatic head resection [DPTPHR], or medial pancreatectomy [MP], maintain pancreatic exocrine function more than conventional pancreaticoduodenectomy (Whipple) or pylorus-preserving pancreaticoduodenectomy (PPPD). A total of 125 patients (18 with Whipple, 71 with PPPD, 13 with DPTPHR, and 23 with MP) were studied. Fecal chymotrypsin and p-type amylase, and pancreatic function diagnostant (PFD) tests were used for evaluation. There were no differences in preoperative background. Pancreatic function was seen to be significantly lower after surgery than before surgery in patients who underwent the Whipple procedure and PPPD (P < 0.05), but there was no difference between pre- and postoperative pancreatic function in patients who underwent DPTPHR and MP. Postoperative pancreatic function was shown to be significantly worse in Whipple procedure and PPPD patients than in those with DPTPHR and MP (P < 0.05). Patients who underwent the Whipple procedure and PPPD showed significantly lower pancreatic function than patients who underwent DPTPHR and MP (P < 0.05). There was no difference in pancreatic function between patients who underwent DPTPHR and those with MP. DPTPHR and MP, both of which preserve the entire duodenum, maintain pancreatic function more than the Whipple procedure and PPPD.

Aged↗
PubMed2000

Congenital hemangiopericytoma: report of a case.

We report a case of congenital hemangiopericytoma arising in the lower right leg of a 4-day-old male neonate. Despite the generally good prognosis associated with this neoplasm, a complete surgical excision has so far been recommended to avoid recurrences, because no definite criteria for determining whether or not the tumor will regress spontaneously have been established to date.

Hemangiopericytoma↗
PubMed2000

Definition of an epitope on Japanese encephalitis virus (JEV) envelope protein recognized by JEV-specific murine CD8+ cytotoxic T lymphocytes.

We defined an epitope on the Japanese encephalitis virus (JEV) envelope (E) protein recognized by CD8+ cytotoxic T lymphocytes (CTLs). CTLs induced in JEV-infected BALB/c (H-2d) mice recognized E and/or premembrane (PrM) proteins, while CTLs in C57BL/6J (H-2b) and C3H/HeJ (H-2k) mice did not. JEV-specific CTLs had a phenotype of CD3+ CD4- CD8+. Twenty-four 9-amino acid (a.a.) peptides, which had binding motifs for H-2Kd, H-2Ld or H-2Dd, were synthesized according to the amino acid sequences of PrM and E proteins. CTLs induced by JEV infection recognized only the peptide K-3. Immunization of BALB/c mice with only a group of peptides including K-3 induced CTLs which recognized the homologous K-3 peptide, while immunization with other peptides did not. The peptide K-3 had a binding motif for H-2Kd. This is consistent with the finding that JEV-specific CTLs in BALB/c mice was H-2Kd-restricted. These results indicate that the epitope recognized by CTLs in BALB/c mice is located between a.a. 60 and 68 on the E protein, corresponding to an a.a. sequence of CYHASVTDI.

Amino Acid Sequence↗
PubMed2000

Job strain, Type A behavior pattern, and the prevalence of coronary atherosclerosis in Japanese working men.

OBJECTIVE: To examine the relation of type A behavior pattern and job strain to angiographically documented coronary stenosis. METHODS: Subjects were 197 male Japanese patients with a full-time job. A questionnaire-based interview elicited psychosocial and other factors. Type A behavior pattern was measured by 12 questions, and job strain by the method of Karasek. Significant coronary stenosis was defined when a 75% or greater luminal narrowing occurred at one or more major coronary arteries or when a 50% or greater narrowing occurred at the left main artery. Logistic regression analysis was used to calculate odds ratio (OR) and 95% confidence interval (CI) with adjustment for traditional coronary risk factors and job type. RESULTS: Type A behavior pattern was related to a statistically non-significant lower prevalence of the coronary stenosis especially in the absence of job strain (adjusted OR 0.6, 95% CI 0.3-1.2). Job strain was non-significantly associated with a modestly increased prevalence of coronary stenosis (OR 1.7, 95% CI 0.6-5.2). CONCLUSION: These findings suggest that both the behavioral pattern and psychosocial work environment may be related to coronary artery stenosis.

Adult↗
PubMed2000

High incidence of silent myocardial ischemia in elderly patients with non insulin-dependent diabetes mellitus.

The present study was designed to reveal the incidence of silent myocardial ischemia in asymptomatic elderly non-insulin-dependent diabetic (NIDDM) patients (aged over 60 years). As a first step screening, maximal treadmill exercise test was performed. Of 140 patients studied, 54 (38.6%) were unable or not expected to achieve diagnostic levels of exercise during treadmill testing. A positive exercise test was noted in 39 of 86 (45.3%) subjects. As a second step examination, dipyridamole thallium scintigraphy was performed for 93 subjects who exhibited a positive exercise test and could not perform a maximal exercise test. Abnormal perfusion pattern was found in 39 of 93 (41.9%), who were finally considered to have a silent myocardial ischemia. Coronary angiography was performed in 18 subjects with diagnosis of silent myocardial ischemia, who gave their consent. Significant coronary artery stenosis was in fact found in 17 of 18 (94.4%) subjects studied, confirming a very high positive predictive value of this diagnostic procedure. In conclusion, elderly NIDDM patients (aged over 60 years) had an extremely high prevalence (estimated 26.3%) of silent myocardial ischemia. This evidence suggests that early and intensive detection may be needed as a part of routine care for this group.

Aged↗
PubMed2000

Low-cariogenicity of trehalose as a substrate.

OBJECTIVES: The effects of trehalose on cariogenesis by mutans streptococci were investigated. METHODS: Inhibited effect of trehalose on water-insoluble glucan (WIG) synthesis from sucrose by glucosyltransferase (GTase) of mutans streptococci was assayed. The acid fermentability of trehalose by mutans streptococci was determined by the measurements of pH, and amounts of lactic acid production. Plaque pH was determined by the measurements of collected plaque from volunteers after sugar mouth-rinse. Rat experimental caries was investigated by feeding a sucrose and/or trehalose diet. RESULTS: Trehalose was not utilized as a substrate for GTase. In addition, trehalose inhibited synthesis of WIG by GTase in the presence of sucrose. Trehalose showed weaker and slower acid fermentation than sucrose by mutans streptococci. The levels of lactic acid production from trehalose by Streptococcus mutans and Streptococcus sobrinus were 24.2 and 59.8% of those from sucrose, respectively. The minimum plaque pH after sucrose mouth-rinse was lower than those after trehalose mouth-rinse in all subjects. Plaque pH after trehalose mouth-rinse never reached critical pH. The substitution of trehalose for sucrose in the rat diet significantly reduced caries scores. Furthermore, rats fed diets containing sucrose and trehalose had significantly lower caries scores than those fed a sucrose diet. CONCLUSIONS: These results suggested that trehalose might be not only lowly cariogenic but also anti-cariogenic, and is promising as a sugar substitute.

Animals↗
PubMed2000

An inference modeling of human visual judgment of sagittal jaw-base relationships based on cephalometry: part I.

When there appears to be a contradiction between a cephalometric tracing and what is seen, the clinician tends to place more reliance on the appearance of the face in profile than on a formal cephalometric evaluation of the sagittal jaw relationship. With this in mind, we derived a multiple regression model with cephalometric variables to explain the visual influences that affect the subjective classification of sagittal jaw relationships made by experienced orthodontists. The regression model that showed the highest coefficient of determination, 0.90, was constructed from a linear combination of the angle ANB, the anteroposterior position of gnathion, the SN length, and the mandibular body length. The performance reliability of the inference system has been tested for 175 female adult cases and will be reported in Part II of this article.

Adolescent↗
PubMed2000

An inference modeling of human visual judgment of sagittal jaw-base relationships based on cephalometry: part II.

In a clinical situation, visual judgment of sagittal jaw-base relationships is described and handled as fuzzy terms, such as "slight" skeletal 3 tendency or "relatively severe" skeletal 2. The purpose of this study was to develop an inference system in order to be able to describe the degree of certainty for sagittal skeletal discrepancy automatically and in a mathematical way. Orthodontic records of 137 adult female patients were judged by 3 orthodontists. Based on these data and the multiple regression model described in Part I of this study, we developed an inference system that consisted of 2 membership functions and 6 incorporating rules. The performance reliability of the system was tested for 175 female adult cases by 7 orthodontic experts. In 97% (170 of 175) of the cases, the orthodontic experts agreed with advice proposed by the inference system. We conclude that the current model is an effective means of deriving the opinion of an experienced clinician from a cephalometric tracing and provides an interesting insight into how orthodontists are influenced by the face when attempting to judge the sagittal relationship clinically. In addition, the current system would be an initial stage in the development of the decision-making system for the orthodontic diagnosis and treatment planning.

Adult↗
PubMed2000

Relation between green tea consumption and the severity of coronary atherosclerosis among Japanese men and women.

PURPOSE: To examine the relation between green tea consumption and arteriographically determined coronary atherosclerosis. METHODS: Study subjects were 512 patients (302 men and 210 women) aged 30 years or older who underwent coronary arteriography for the first time at four hospitals in Fukuoka City or one hospital in an adjacent city between September 1996 and August 1997. Lifestyle characteristics including green tea consumption were ascertained before arteriography by a questionnaire supported with interview. RESULTS: 117 men (38.7%) and 50 women (23.8%) had significant stenosis of one or more coronary arteries. Green tea consumption tended to be inversely associated with coronary atherosclerosis in men, but not in women. An evident, protective association between green tea and coronary atherosclerosis was observed in a subgroup of 262 men excluding those under dietary or drug treatment for diabetes mellitus. In this subgroup, after adjustment for traditional coronary risk factors and coffee, odds ratios of significant stenosis for consumption of 2-3 cups and 4 or more cups per day were 0.5 (95% confidence interval 0.2-1.2) and 0.4 (0.2-0.9), respectively, as compared with a consumption of one cup per day or less. CONCLUSIONS: The results indicate that green tea may be protective against coronary atherosclerosis at least in men.

Adult↗