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Biomedical subjects

Y Takemoto

Publications and source records attributed to Y Takemoto.

At least 163 records · Page 9Linked to original sources
PubMed1995

[Assessment of bone mineralization of hemodialyzed patients with SPA and DPA--different effect of PTX with the site].

We analyzed the bone changes at each site of secondary hyperparathyroidism (2 degrees HPT) on hemodialyzed patients using both single photon absorptiometry (SPA) and dual photon absorptiometry (DPA). The subjects were 35 hemodialysis patients (12 male, 24 female) with 2 degrees HPT. The bone mineral densities (BMD) of 1/3 radius, head, total body and 3rd lumbar spine were measured before and after parathyroidectomy (PTX). Before PTX, the BMD of 2 degrees HPT patients were lower than the normal range of all sites, especially at the radius which mainly consisted of cortical bone. After PTX, the BMD at all sites increased especially in the head. The BMD of the radius also continued to increased up two years after PTX, but it was not as increased as the BMD of head. The BMD of the lumbar spine which consisted of cancellous bone mainly increased after PTX for one year and decreased thereafter. This decrease was influenced by age. There was a difference with the site of BMD after PTX. The determination of changes of BMD of head and radius was considered useful for the judgment of treatment.

Absorptiometry, Photon↗
PubMed1994

Multiple nuclear localization signals of the B-myb gene product.

Nuclear entry of the B-myb gene product (B-Myb) is dependent on multiple nuclear localization signals (NLS's). Mutagenesis of the putative NLS's of B-Myb has identified two separate NLS's, NLS1 and NLS2. Each of the two NLS's is essential for efficient nuclear targeting. NLS2 contains two interdependent basic domains separated by 8 intervening spacer amino acids, and both basic domains are required for nuclear entry. Thus, NLS2 belongs to a class of bipartite NLS's. Like the NLS's in yeast transcription factor SW15, NLS2 contains a putative cdc2 kinase site. However, unlike the case of SW15, phosphorylation at this site did not affect the nuclear targeting of B-Myb.

Amino Acid Sequence↗
PubMed1994

Characteristics of dynamic mutation in Japanese myotonic dystrophy.

To study the characteristics, if any, of unstable CTG repeat sequence in Japanese myotonic dystrophy (DM), we analyzed DNA from 351 at risk individuals (including affected and non-affected carriers and their descendants) from 105 families in Japan. A total of 93 DM families (196 affected and 116 unaffected individuals), including 84 DM parent-child pairs (44 father-child and 40 mother-child pairs), were examined, many of which had been previously tested by linkage analysis. We detected unstable CTG repeat mutations between 0.15 kb and 8.7 kb in size. The size of the mutation correlated with the age of onset of symptoms. There was a significant difference in DM allele size among the four groups (congenital, juvenile onset, classical, and minimal). Congenital DM had on average the largest repeat sizes. Comparison of parent-child pairs showed that most offspring had a larger repeat size than their parents, with only 2 of 84 showing a definite decrease in repeat size. The correlation coefficients for maternal and paternal transmission were 0.41 and 0.15, respectively. The parental age (maternal and paternal) did not correlate with intergenerational change of repeat. These observations are similar to those reported in Caucasians.

Adolescent↗
PubMed1994

Calcium in pig livers following ischemia and reperfusion.

Calcium concentrations in pig livers were serially estimated following ischemia-reperfusion. Ischemia was produced by clamping the hepatic artery and the portal vein for 90 min (Group 1, n = 6) or for 180 min (Group 2, n = 6) during temporary side-to-side portacaval shunt performed before the induction of ischemia. Although there were no significant changes in hepatic calcium concentrations during ischemia, an immediate accumulation of calcium occurred 30 min after reperfusion in both groups. After these increases, the hepatic calcium concentration decreased to near the pre-ischemic level within 20 min in all animals in Group 1. The recovery of calcium was incomplete in Group 2. When the peak was defined as the highest level of calcium and the bottom as the lowest point after peak 60 min after reperfusion, the mean-peak was 11.0 +/- 1.3 (mean +/- SEM) nmol/mg dry weight liver in Group 1 and 12.8 +/- 1.4 nmol/mg dry weight liver in Group 2 (not significant). However, the mean-bottom in Group 1 was lower than that in Group 2 (5.5 +/- 0.3 and 8.1 +/- 0.8 nmol/mg dry weight liver, respectively, p < 0.05). These results indicate that hepatic calcium increases immediately after reperfusion and that recovery from this calcium accumulation seems to be a crucial factor for minimizing cellular injury.

Analysis of Variance↗
PubMed1994

Effect of verapamil on hepatic reperfusion injury after prolonged ischemia in pigs.

This study investigated the effect of verapamil on prolonged and severe ischemic injury and elucidated the association of the calcium blocking action with cellular injury, assessing changes in hepatic calcium concentrations during ischemia and reperfusion in pigs. Hepatic ischemia was produced for 180 min by clamping both the hepatic artery and portal vein during temporary portacaval shunt performed before the induction of ischemia. Pigs were divided into two groups: the animals in the verapamil group (Group V, n = 6) received continuous administration of 0.025 mg/kg per min of verapamil intraportally for 20 min before ischemia. The control group (Group C) received nothing. A better survival rate was observed in Group V than in Group C (p < 0.01), but serum aspartate aminotransferase was higher in Group V after reperfusion (p < 0.05). There were no significant changes in hepatic calcium concentrations during ischemia in either group, but it increased immediately after reperfusion in both groups. However, no significant difference was found between the two groups. Recovery of the pyruvate/lactate ratio in Group V tended to be better after reperfusion compared to Group C (p = 0.08). These data suggest that the pre-ischemic administration of verapamil produced better survival in animals after prolonged normothermic ischemia. However, the reperfused liver suffered more severe damage in the first 6 h after reperfusion in the verapamil-treated animals. Moreover, there seemed to be very little blocking action of calcium influx. A reduced oxygen requirement may be involved in the protective action of verapamil on animal survival.

Animals↗
PubMed1994

Changes in calcium content of the liver during hepatic ischemia-reperfusion in dogs.

Alteration of calcium metabolism in cells has been thought to be one of the main factors in ischemia-reperfusion injury. Serial changes in the tissue calcium content of the liver and the correlation between calcium level and liver injury were investigated. Experimental dogs were divided into two groups and subjected to hepatic ischemia of different duration: 60 min in Group A and 120 min in Group B, followed by reperfusion. Serum alanine aminotransferase, as an indicator of liver injury, was more elevated in Group B than in Group A. There was no change in hepatic calcium content during ischemia in either group. Immediately after reperfusion, there was no change in hepatic calcium level in Group A, whereas in Group B it was markedly elevated. The peak value occurred 30 min after reperfusion and gradually decreased thereafter, but did not return to pre-ischemic levels during the observation time. Plasma calcium concentrations in hepatic venous blood were markedly decreased in Group B 30 min and 60 min after reperfusion. These results suggest that calcium accumulation in the liver during the early reperfusion period may be one of the mediators of hepatic injury. To elucidate the mechanisms for elevation of calcium in hepatic tissue, serum malondialdehyde, a product of lipid peroxidation, was measured in hepatic venous blood. No elevation of serum malondialdehyde was observed in either group, indicating that the increases in calcium may not be due to oxidative stress. Serum mitochondrial aspartate aminotransferase and electron microscopic findings were used as indicators of mitochondrial injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine Transaminase↗
PubMed1994

[MECHOP-BM chemotherapy in the treatment of non Hodgkin's lymphoma].

Twenty patients with previously untreated advanced aggressive or relapsed or refractory non-Hodgkin's lymphoma were treated with the MECHOP-BM regimen (MCNU, etoposide, cyclophosphamide, adriamycin, vincristine, prednisolone, bleomycin and methotrexate). Of the 18 patients treated with the MECHOP-BM, the response rate was 78% and complete response (CR) was attained in 33%. Among these CR patients, one patient relapsed, but the other patients continued to show CR (59-243 days, medium 178 days). The most serious toxicity attributed to MECHOP-BM therapy was leukopenia. The mean white blood cell count dropped to 1,300/microliters, and only therapy could be useful in the treatment for patients with untreated aggressive and advanced stage of non-Hodgkin's lymphoma as well as salvage therapy of relapsed cases.

Adolescent↗
PubMed1993

Functional domains of the human B-myb gene product.

Three members of the human myb gene family (c-myb, A-myb, and B-myb) encode transcriptional regulators that can bind to specific DNA sequences. High levels of c-myb expression are usually found in immature hemopoietic cells, but the B-myb is more commonly expressed in many types of cells. To understand the regulation of the activity of B-myb gene product (B-Myb), its functional domains were analyzed. Like c-Myb, B-Myb also has a transcriptional activation domain containing a cluster of acidic amino acids in the region downstream of the DNA-binding domain, which consists of three tandem repeats of 51-52 amino acids. In contrast to c-Myb, B-Myb does not contain a negative regulatory domain. Furthermore, the multiple nuclear localization signals are in at least two regions in the COOH-terminal half of B-Myb, and one of them is adjacent to a potential cdc2 kinase site. These results indicate that B-Myb contains DNA-binding and transcriptional activation domains similar to those of c-Myb, but a regulatory mechanism of B-Myb activity is quite different from that for c-Myb.

Actins↗
PubMed1993

Sequence specific binding of Ets-1 to the mouse cytokeratin EndoA gene enhancer.

Expression of the mouse cytokeratin EndoA gene is regulated by an enhancer that is located 1 kilobases (kb) 3' downstream from the gene. The EndoA enhancer consists of six direct repeats with homology to the PEA3 motif in the polyoma virus enhancer core. The PEA3 motif binds to the proto-oncogene Ets product. In this report we show that GST-c-Ets-1 fusion protein binds specifically to the EndoA enhancer unit sequence by gel shift analysis. Footprinting showed that the Ets-1 binding site consisted of 20 bases in each repeat. Ets-1 also moderately activated the EndoA enhancer. These results demonstrate that Ets-1 binds in a sequence specific fashion to the mouse EndoA enhancer and suggest that c-Ets-1 or other related Ets family genes function in regulating EndoA gene expression.

Animals↗
PubMed1993

Identification of differentiation-dependent DNase I-hypersensitive sites in the mouse EndoA gene.

DNase I hypersensitive (DH) sites in a 12-kb genomic fragment carrying the mouse EndoA gene were examined to obtain information on the changes in chromatin structure associated with activation of this gene encoding extra-endodermal cytoskeletal protein A (EndoA) during early mouse embryogenesis. Seven DH sites were found in this locus in parietal yolk-sac-like cells, PYS-2, which produce EndoA constitutively. In differentiated mouse teratocarcinoma F9 cells that produce EndoA inductively, this locus has three DH sites. In both cell lines, these sites were mapped to the upstream region of the promoter, the promoter and the 3' enhancer region. The DNA of PYS-2 cells has one more DH site within the first exon and three additional DH sites within the first intron. These DH sites are not present in DNA from BALB/c 3T3 cells and undifferentiated F9 cells that do not produce EndoA. Thus, the formation of these differentiation-dependent DH sites is required for the differentiation-specific expression of the mouse EndoA. In addition, another strong DH site, which may be associated with the B2 element expression, was detected in the third intron of the gene in undifferentiated F9 cells.

3T3 Cells↗
PubMed1993

Lack of intratumoral heterogeneity in DNA ploidy pattern of hepatocellular carcinoma.

BACKGROUND: From biological and clinical perspectives, it is important to clarify tumor heterogeneity. This study was aimed to investigate whether or not intratumoral heterogeneity of DNA ploidy pattern exists in hepatocellular carcinoma (HCC). METHODS: Using fresh materials resected from 31 untreated patients, DNA ploidy was analyzed at different sites of the same HCC by means of flow cytometry. The tumor size ranged from 1.7 to 25.0 cm. RESULTS: There was no case in which euploid and aneuploid HCCs coexisted in the same tumor. The DNA ploidy pattern was euploid in 15 and aneuploid in 16 instances. Of 15 euploid tumors, the areas analyzed were all diploid in 12 and tetraploid in 2 but diploid/tetraploid in 1. Among 16 aneuploid tumors, the DNA indices (DI) at different sites were similar in 9, but apparently, different aneuploid subclones coexisted in 7 cases. The incidence of DI heterogeneity in aneuploid HCCs was similar between small (< 5 cm) and large (> or = 5 cm) tumors; 3 of 7 (42.9%) versus 4 of 9 (44.4%). CONCLUSIONS: It is assumed that euploid and aneuploid HCCs develop in their own ploidy pattern and that the evolution of aneuploid subpopulations from euploid HCC is rare, but new aneuploid subclones can evolve from aneuploid HCC due to increased instability of its karyotype.

Adult↗
PubMed1993

Incidence and factors associated with intrahepatic recurrence following resection of hepatocellular carcinoma.

BACKGROUND: The long-term survival rate after liver resection of hepatocellular carcinoma (HCC) is far from satisfactory, mainly because of high intrahepatic recurrence (IHR) rates. This study was aimed to clarify clinicopathologic factors relevant to IHR after resection of HCC. METHODS: The 10-year cumulative intrahepatic recurrence rates were analyzed in terms of seven clinical and eight pathological factors in 201 patients with curative hepatic resection. RESULTS: IHR was found in 121 patients during the follow-up period. The overall IHR rates were 22% at 1 year, 43% at 2 years, 62% at 3 years, 72% at 4 years, 75% at 5 years, and 75% at 10 years. Age, sex, and serum alpha-fetoprotein level, hepatitis B virus markers, and extent of liver resection were not significantly related to the IHR rate. Postoperative chemotherapy mainly with anthracycline tended to suppress IHR (P = 0.0889), but preoperative chemoembolization did not affect IHR. The presence of cirrhosis, satellite nodules, and venous invasion and the absence of capsule formation were associated with higher recurrence rates throughout the observation. Positive surgical margin (< or = 5 mm) was also associated with a higher IHR rate. Although not significant, well-differentiated HCCs showed a higher recurrence rate in comparison with poorly differentiated tumors. Size and number of tumor did not influence the IHR rate. CONCLUSIONS: Accurate patient selection and adequate hepatic reserve are important considerations in the management of HCC by resection.

Aged↗
PubMed1993

Maturation in larch: age-related changes in xylem development in the long-shoot foliage and the main stem.

As the meristems of eastern larch (Larix laricina (Du Roi) K. Koch) mature, they produce long-shoot foliage with progressively higher chlorophyll content and net photosynthesis and progressively lower specific leaf area (Hutchison et al. 1990). Despite the apparent increase in foliar vigor, both shoot height and diameter growth rates declined during maturation. These changes were associated with changes in xylem morphology of the vascular tissue of both the long-shoot foliage and the main stem. Although the number of xylem cells remained constant in a cross section of the foliage, their diameters increased with age. With increasing maturation, the same number of xylem cells were produced per radial file in the annual rings of the main stem, but their radial diameters decreased, which accounted for the decrease in diameter growth. There was no change in tracheid length during maturation. We conclude that the decrease in growth rate with increased maturation is not due to a decrease in physiological vigor of the foliage, but is a function of reduced sink strength of the growing shoots.

Journal Article↗
PubMed1993

Liver resection for hepatocellular carcinoma. Results of 229 consecutive patients during 11 years.

OBJECTIVE: This study analyzed the results in 229 patients with primary hepatocellular carcinoma (HCC) who were treated by radical hepatic resection in the past 11 years. SUMMARY BACKGROUND DATA: Due to marked advances in diagnostic and therapeutic methods, the therapeutic strategy for HCC has changed significantly. However, there are still many problems to be solved when hepatic resection is to be performed for HCC associated with chronic liver disease. A satisfactory result may be possible only when all of accurate operative indication, skillful surgical technique, and sophisticated postoperative management are met. METHODS: There were 188 men and 41 women. Age ranged from 32 to 79 years averaging 60.8. Underlying cirrhosis of the liver was found in 177 patients, and chronic hepatitis was found in 47 instances. Before surgery, 114 patients had 157 associated conditions; diabetes mellitus in 66, esophageal varices in 42, cholelithiasis in 22, peptic ulcer in 12, and miscellaneous in 15 cases. In addition to various types of hepatic resection, 69 patients underwent concomitant operations such as cholecystectomy, the Warren shunt, splenectomy, partial gastrectomy, and so forth. RESULTS: The 30-day (operative) mortality rate was 7.0%, and there were eight additional late deaths (3.5%). Child's class, bromosulphalein (BSP) test, and the estimated blood loss during surgery were good predictors for operative death. The cumulative 5- and 10-year survival rates for all patients were 26.4% and 19.4%, respectively. At present, 110 patients are alive; 2 more than 10 years and 21 more than 5 years. Younger age, absence of cirrhosis, smaller tumor, and postoperative chemotherapy were associated with increased survival. CONCLUSIONS: The results of hepatic resection in 229 patients with HCC were analyzed. Child's class, BSP test, and blood loss during surgery were good predictors for operative death. The 5- and 10-year survival rates were 26.4% and 19.4%, respectively. Age, liver cirrhosis, tumor size, and postoperative chemotherapy were prognostic factors. Multidisciplinary approach with liver resection, postoperative chemotherapy, and liver transplantation will be a realistic direction for the surgical treatment of HCC in future.

Blood Loss, Surgical↗
PubMed1993

Clonal evolutions during long-term cultures of bone marrow from de novo acute myeloid leukaemia with trilineage myelodysplasia and with myelodysplastic remission marrow.

We previously established a long-term bone marrow culture (LTBMC) system in which novel abnormal karyotypes could emerge in vitro prior to the appearance of the same karyotypes in vivo in patients with myelodysplastic syndrome (MDS). We extended our study to examine whether acute myeloid leukaemia (AML) transformed from MDS (MDS/AML) and de novo AML with trilineage myelodysplasia (AML/TMDS) show clonal evolution in LTBMC similar to that of typical AML or MDS. We also analysed the cytogenetic changes in cultures with bone marrows from AML with myelodysplastic remission marrow (AML/MRM) as well as chronic myeloid leukaemia (CML) to compare them with typical AML with respect to the liability of clonal evolution. Among the 34 AML cases, abnormal karyotypes were newly detected in four of seven MDS/AML, three of six AML/TMDS and three of three AML/MRM. Novel abnormal karyotypes were also observed in nine out of 13 CML cases after culture. In contrast, no other abnormal karyotypes were found after culture in 18 typical AML without myelodysplasia. These findings suggest that AML/TMDS and AML/MRM are different from typical AML and are similar to MDS/AML and CML in view of their potential for disease progression from latent multiple clones. Typical AML may develop from a single abnormal clone without any subclones.

Anemia, Aplastic↗
PubMed1993

[Rapid diagnosis of cytomegalovirus interstitial pneumonitis by the polymerase chain reaction method--comparison of four diagnostic procedures].

The authors conducted a comparative study on the rapid diagnosis of cytomegalovirus (CMV) interstitial pneumonitis by 4 different methods. Among them, the polymerase chain reaction (PCR) method was found to achieve the most rapid diagnosis of CMV infection. The clinical usefulness of making a diagnosis from the serum antibody titer and viral isolation was questionable as compared with the PCR method. Therefore, early diagnosis of CMV infection by PCR may be promising especially for the compromised patients with hematological diseases.

Base Sequence↗
PubMed1993

Regional vasoconstriction and excessive grooming induced by L-arginine injection into the cisterna magna of conscious rats.

Hemodynamic and behavioral changes caused by intracisternally injected L-arginine which has a pressor effect were studied in conscious rats. One week or more after inserting a cannula into the cisterna magna, electromagnetic flow probes were implanted around the superior mesenteric artery, renal artery, or terminal aorta under anesthesia. A catheter for measurement of blood pressure was inserted into the terminal aorta via a femoral artery or into the common carotid. After recovery from surgery, blood flow, arterial blood pressure, heart rate, and behaviors were observed in the conscious state. Peripheral resistance, calculated as pressure divided by flow, increased an average of 80% in the superior mesenteric artery and 60% in the renal artery when the pressure was increased by 25% following intracisternal injection of 5 mumol of L-arginine. Hindquarter (terminal aortic) resistance showed an insignificant decrease of about 10%. The average heart rate showed no significant change. Grooming, moving, and eating all increased significantly after injection of L-arginine. Circulatory events and behaviors did not always synchronize after the injection. Intravenous chlorisondamine chloride, a ganglion blocker, significantly attenuated the pressor effect caused by intracisternal injection of L-arginine. These findings indicate that centrally injected L-arginine not only specifically triggers vasoconstriction in the viscera presumably through excitation of the regional sympathetic vasoconstrictor fibers to raise blood pressure but also centrally induces excessive grooming. However, the relationship between circulation and behavior caused by intracisternal injection of L-arginine remains unknown.

Animals↗