Biomedical subjects

K Hatakeyama

Publications and source records attributed to K Hatakeyama.

At least 163 records · Page 9Linked to original sources

PubMed1999

Stretching of the ductus: an important factor in determining the outcome of coil occlusion.

The present study measured the minimal diameter of the ductus (minimal D), the stretched minimal diameter (stretched D), and the stretch index (SI) before coil occlusion in 25 patients with a patent arterial duct. The following factors were compared in the success group (22 cases, coil successfully placed after initial deployment) versus the failure group (3 cases): minimal D, stretched D, SI, the sum of the loop diameter of coils (the loop diameter), the sum of the product of the loop diameter and the number of loops (the loop diameter and number), the loop diameter/minimal D, the loop diameter/stretched D, the loop diameter and number/minimal D, and the loop diameter and number/stretched D. In the failure group, minimal D, stretched D, SI, the loop diameter, and the loop diameter and number were larger than in the success group. The loop diameter/stretched D, and the loop diameter and number/stretched D were smaller in the failure group. Although the loop diameter and number/minimal D was slightly smaller in the failure group, the loop diameter/minimal D was comparable. It is concluded that the stretched D is more reliable than minimal D to determine the appropriate size of coil for successful initial deployment.

Adolescent↗

PubMed1999

The role of Kupffer cells in liver regeneration.

The liver has a remarkable proliferative capacity after a partial hepatectomy. Previous studies have indicated that Kupffer cells have the potential to exert both stimulatory and inhibitory influences on hepatocyte proliferation. To elucidate the role of Kupffer cells in liver regeneration, mice were selectively depleted of Kupffer cells by injection of liposome-encapsulated dichloromethylene diphosphonate (lipo-MDP) at day 3 after a two-thirds hepatectomy. Results showed that liver regeneration was delayed after Kupffer cell-depletion. In control mice, hepatocyte growth factor (HGF) mRNA expressions were enhanced during liver regeneration and expressions of HGF were localized in fat-storing cells (Ito cells). In Kupffer cell-depleted mice, the number of HGF-expressing cells decreased in the regenerating liver, and expressions of HGF and its receptor (c-met) as well as other growth factors/cytokines were less prominent than in control mice. In contrast, expressions of TNF-alpha, another potent cytokine involved in liver regeneration, did not differ between Kupffer cell-depleted and control mice during the regeneration. Administration of TNF-alpha antibody did not reduce the expression of HGF or liver regeneration. These findings imply that Kupffer cells play a stimulatory role in liver regeneration by enhancing HGF expression via TNF-alpha-non-mediated mechanisms.

Animals↗

PubMed1999

Apoptosis and Bbcl-2 expression in gastric carcinomas: correlation withclinicopathological variables, p53 expression, cell proliferation and prognosis.

We investigated apoptosis and Bcl-2 expression in 221 advanced gastric carcinomas in correlation with clinicopathological variables, p53 expression, cell proliferation and prognosis, using the in situ DNA nick end labeling method and immunohistochemistry. Apoptosis was associated with high immunoreactivity of proliferating cell nuclear antigen. Bcl-2 expression correlated with a low apoptotic index and less malignant behavior of tumors. Prognostically, Bcl-2 expression was associated with a better prognosis, whereas p53 expression was the most important prognostic risk factor. Thus, apoptosis in gastric carcinomas is associated with cell proliferation, and Bcl-2 expression may have a prognostic importance as well as p53 expression.

Apoptosis↗

PubMed1999

Extended radical esophagectomy for superficially invasive carcinoma of the esophagus.

BACKGROUND: The purpose of the study was to determine whether extended radical esophagectomy is both clinically and oncologically indicated for patients with superficially invasive esophageal carcinomas. METHODS: We reviewed 51 patients with this disease in whom extended radical esophagectomy was performed. RESULTS: Major morbidity developed in 80% of the patients associated with no mortality after the operation. At surgery lymph node metastases were found in 29 patients (57%). Although the number of positive nodes was 3 or less in 93% of those patients, the tumors metastasized not only to the mediastinal nodes but also to the cervical and abdominal nodes, frequently jumping the first echelon of nodes. The overall 5-year survival rate was 68%. The survival curve of the patients with positive nodes was significantly worse (P < .01) than that of patients with negative nodes: the respective 5-year survival rates were 47% and 93%. However, no significant difference was detected between the survival curves of the patients with cervical metastases and those with noncervical metastases. CONCLUSIONS: Extended radical esophagectomy is needed for complete tumor clearance and may be effective in improving the rate of cure in patients with superficially invasive esophageal carcinoma. However, patients should be selected carefully for the performance of extended radical esophagectomy because this procedure is potentially associated with high morbidity rates.

Adult↗

PubMed1999

[High throughput gene analysis with DNA array--from sequencing to expression monitoring].

Proceedings of DNA array technology opened the way for the high throughput gene analysis, such as sequence analysis by hybridization (SBH) or gene expression monitoring. SBH, based on the ability to determine a DNA sequence by hybridizing oligonucleotide probes to the target DNA, appears to be a method with great potential for megabase sequencing. One of the most serious problems is that SBH requires extremely highly specific hybridization conditions which can discriminate one-base mismatches against a perfect match. We proposed new probe designs that contain several universal bases at both ends. By using these stacking probes, we could obtain not only strong hybridization signals, but also high discrimination values.

DNA Probes↗

PubMed1999

Optimization of ex vivo inducible nitric oxide synthase gene transfer to vein grafts.

BACKGROUND: Vein graft failure as the result of intimal hyperplasia (IH) remains a significant clinical problem. Ex vivo modification of vein grafts using gene therapy is an attractive approach to attenuate IH. Gene transfer of the inducible nitric oxide synthase (iNOS) gene effectively reduces IH. However, iNOS activity after gene transfer may be impaired by the availability of cofactor, such as tetrahydrobiopterin (BH4). The purpose of this study is to determine the optimal conditions for ex vivo adenoviral-mediated iNOS gene transfer into arterial and venous vessels. METHODS: Porcine internal jugular veins and carotid arteries were infected ex vivo with the adenoviral iNOS vector (AdiNOS) and with an adenovirus carrying the cDNA encoding guanosine triphosphate cyclohydrolase I (AdGTPCH), the rate-limiting enzyme for BH4 synthesis. The production of nitrite, cyclic guanosine monophosphate (cGMP), and biopterin were assessed daily. RESULTS: Nitric oxide (NO) production after iNOS gene transfer was maximal when vessels were cotransduced with AdGTPCH. NO production in these vessels persisted for more than 10 days. Vein segments generated approximately 2-fold more nitrite, cGMP, and biopterin than arterial segments infected with AdiNOS/AdGTPCH. Submerging vein segments into adenoviral solution resulted in improved gene transfer with greater nitrite and cGMP release compared with infections carried out under pressure intraluminally. Similarly, injury to the vein segments before infection with AdiNOS resulted in less nitrite production. CONCLUSIONS: These data demonstrate that AdiNOS can efficiently transduce vein segments ex vivo and that the cotransfer of GTPCH can optimize iNOS enzymatic activity. This cotransfer technique may be used to engineer vein grafts before coronary artery bypass to prevent IH.

Adenoviridae↗

PubMed1999

[Developmental changes of awareness during passive and active attentions: evaluation of serial event-related potentials (N130, N180, P250)].

Serial event-related potentials (ERPs), especially the negative components before P300, were recorded to evaluate the developmental changes of awareness, or intentional attention. In this study, 36 healthy children (5-16 years of age) and eight healthy adults (19-37 years) were told to perform two attentive paradigms: passive and active. Each test condition consisted of 16 electrical stimuli. Four trials were averaged in sequence and then evaluated as serial four blocks. With repetition in both passive and active attentive paradigms the amplitude of N130 was not attenuated until six years old. During active attention, N180 remained undiminished in adolescents and adults. The amplitude of P250 decreased with repetition during passive attention in children over seven years old, but was not attenuated during active attention in adults. These results suggest that N130 reflects the orienting reflex, and that N180 is associated with the process to maintain awareness.

Adolescent↗

PubMed1999

[Quantitative measurement of prefrontal lobe volume on three dimensional magnetic resonance imaging scan].

This article describes the measurement of the frontal and prefrontal lobe volumes on three dimensional (3-D) MRI in 13 children aged 5 months to 14 years and in 3 adults aged 27 to 39 years. The 3-D MRI data were acquired by the fast spoiled gradient recalled (SPGR) sequence using a 1.5 T MR imager. The frontal and prefrontal lobe volumes were measured by the volume measurement function of the Workstation. We confirmed that this technique to analyze segmental brain volumes achieved acceptable levels of reliability and accuracy. There was an increase in the frontal and prefrontal lobe volumes with advancing age, being rapid between 8 and 15 years of age. The prefrontal to frontal lobe volume ratio also increased gradually, with spurts between 8 and 15 years of age. This approach may be particularly useful for studies on patients with frontal and prefrontal lobe dysfunctions.

Adolescent↗

PubMed1999

Anomalous insertion of the right hepatic duct into the cystic duct: report of a case diagnosed before laparoscopic cholecystectomy.

Although an aberrant hepatic duct entering the cystic duct is not especially rare, the main right hepatic duct entering the cystic duct is extremely rare, with only six cases reported thus far. All of the reported patients underwent open cholecystectomy, during which one patient received a bile duct injury. The anomaly was unsuspected preoperatively in all of these cases. We report an additional patient with this anomaly, the first such case diagnosed before laparoscopic cholecystectomy using direct cholangiography. Cholangiography may be mandatory whenever biliary anomalies are suspected during laparoscopic cholecystectomy. As the right hepatic duct entering the cystic duct can lead to ductal injury, this anomaly should be kept in mind when performing laparoscopic cholecystectomy.

Adult↗

PubMed1998

Decameric GTP cyclohydrolase I forms complexes with two pentameric GTP cyclohydrolase I feedback regulatory proteins in the presence of phenylalanine or of a combination of tetrahydrobiopterin and GTP.

The activity of GTP cyclohydrolase I is inhibited by (6R)-L-erythro-5,6,7,8-tetrahydrobiopterin (BH4) and stimulated by phenylalanine through complex formation with GTP cyclohydrolase I feedback regulatory protein (GFRP). Gel filtration experiments as well as enzyme activity measurements showed that the number of subunits of GFRP in both the inhibitory and stimulatory complexes is equal to that of GTP cyclohydrolase I. Because GFRP is a pentamer and GTP cyclohydrolase I was shown here by cross-linking experiments to be a decamer, the results indicate that two molecules of a pentameric GFRP associate with one molecule of GTP cyclohydrolase I. Gel filtration analysis suggested that the complex has a radius of gyration similar to that of the enzyme itself. These observations support our model that one molecule of GFRP binds to each of the two outer faces of the torus-shaped GTP cyclohydrolase I. For formation of the inhibitory protein complex, both BH4 and GTP were required; the median effective concentrations of BH4 and GTP were 2 and 26 microM, respectively. BH4 was the most potent of biopterins with different oxidative states. Among GTP analogues, dGTP as well as guanosine 5'-O-(3'-thiotriphosphate) exhibited similar inducibility compared with GTP, whereas other nucleotide triphosphates had no effect. On the other hand, phenylalanine alone was enough for formation of the stimulatory protein complex, and positive cooperativity was found for the phenylalanine-induced protein complex formation. Phenylalanine was the most potent of the aromatic amino acids.

Animals↗

PubMed1998

Regulation of expression of human intestinal bile acid-binding protein in Caco-2 cells.

Molecular mechanisms of the bile acid active transport system in the ileal enterocytes remain unknown. We examined whether bile acids affect human enterocyte gene expression of intestinal bile acid-binding protein (I-BABP), a component of this transport system. Differentiated Caco-2 cells were incubated in the presence of human bile, bile acids or other lipids. The level of I-BABP expression was evaluated by Northern and Western blot analyses. A 24 h incubation of Caco-2 cells in a medium containing either bile or bile acids resulted in a remarkable 7.5-fold increase in the I-BABP mRNA level over the control level. Neither cholesterol, palmitic acid, phosphatidylcholine nor cholestyramine treated bile showed any difference in I-BABP mRNA expression from the control. Bile acid treatment increased the level of I-BABP mRNA in Caco-2 cells in a time- and dose-dependent manner. Western blot analysis showed that this induction led to increase in cytosolic I-BABP. Chenodeoxycholic acid and deoxycholic acid showed greater induction effects than other hydrophilic bile acids, including their own glycine conjugates. Pretreatment by actinomycin D or cycloheximide completely inhibited the up-regulation of I-BABP expression by bile acid. Bile acids, especially lipophilic bile acids, increase the I-BABP expression in Caco-2-cells, suggesting that luminal bile acids play an important role in regulating the I-BABP gene expression.

Bile Acids and Salts↗

PubMed1998

Do the level of nodal disease according to the TNM classification and the number of involved cervical nodes reflect prognosis in patients with differentiated carcinoma of the thyroid gland?

BACKGROUND AND OBJECTIVES: The importance of nodal involvement as a prognostic factor in differentiated carcinoma of the thyroid gland remains controversial. We therefore attempted to confirm the prognostic factors in differentiated thyroid carcinoma, with special reference to nodal status. PATIENTS AND METHODS: A total of 139 patients with differentiated thyroid cancer followed for 2-27 years, with a median follow-up of 7 years were studied. All patients underwent surgical resection, either subtotal, total, or lobectomy, with modified radical neck dissection. Survival was calculated using the Kaplan-Meier method. RESULTS: Ten (7%) patients have died from thyroid cancer. Adverse prognostic factors included age >45 years (P=0.0120), the presence of distant metastases (P=0.0006), and TNM stage (P=0.0002). The number of lymph nodes dissected ranged from 6 to 92, with an average of 26. Lymph node metastases were found in 102 (73%) patients. There was no difference in survival according to the level of nodal disease by the TNM classification. Furthermore, the number of cervical lymph nodes involved had no effect on the survival. CONCLUSION: Our results suggest that the presence of histologically confirmed lymph node metastases is not an important prognostic factor in patients with differentiated thyroid carcinoma.

Adult↗

PubMed1998

Low level of mixing of partner cells seen in extrathymic T cells in the liver and intestine of parabiotic mice: its biological implication.

c-kit+ stem cells have recently been found in the liver and intestine of adult mice. We examined whether such stem cells give rise to extrathymic T cells in these organs in situ. To this end, we used parabiotic B6.Ly5.1 and B6.Ly5.2 mice, i.e. mice sharing the circulation. The origin of lymphocytes was identified by anti-Ly5.1 and anti-Ly5.2 monoclonal antibodies in conjunction with immunofluorescence assays. Lymphocytes in the blood, spleen, lymph nodes and liver had become a half-and-half mixture of Ly5.1+ and Ly5.2+ cells in both individuals by day 14. However, this level of mixing decreased in extrathymic T cells in the liver (i.e. NK T cells) and intestine by day 14 and thereafter. The same was observed in T cells of the thymus. The data from immunohistochemical staining supported the results of immunofluorescence assays for suspension cells. The present results raise the possibility that extrathymic T cells in the liver and intestine may arise from their own pre-existing precursor cells, possibly from their own stem cells. Another important finding was that the composition pattern of lymphocyte subsets in one individual was quite similar to that in its partner at various sites. This result was interpreted to mean that only selected partner cells migrate to specific sites in the other partner individual.

Animals↗

PubMed1998

Bowel perforation caused by silicone drains: a report of two cases.

We recently encountered two patients who suffered bowel perforation due to pressure necrosis caused by an open silicone drain placed in the abdominal cavity during surgery. These perforations healed spontaneously after removal of the drains from the site of perforation. Silicone drains are frequently placed in the abdominal cavity to prevent the collection of fluid or blood following surgery; however, a risk of this complication must be borne in mind. Our review of the English literature revealed eight cases of bowel perforations occurring due to a drainage system; six to closed suction drains, and two to open drainage tubes. Seven of these eight patients underwent repeat laparotomy for peritonitis, while the remaining one, who had a closed suction drain, was managed conservatively following discontinuation of the vacuum. Our experience and the literature review suggest that conservative management may be possible in patients without any signs of generalized peritonitis, although repeat laparotomy is required for those with generalized peritonitis. In conclusion, drains should be placed carefully in the abdominal cavity and removed early after the drainage has decreased.

Aged↗

PubMed1998

Esophageal intramural metastasis from an adenocarcinoma of the gastric cardia: report of a case.

We report herein the rare case of a 65-year-old man found to have esophageal intramural metastasis from cancer of the gastric cardia. Endoscopic examination initially revealed an infiltrating ulcerative tumor of the gastric cardia involving the esophagogastric junction, as well as a submucosal tumor of the lower esophagus. A total thoracic esophagogastrectomy with lower mediastinal lymphadenectomy was performed, and the resected specimen demonstrated that both the cardia and esophageal tumors were adenocarcinomas with the same cellular differentiation. As lymphatic invasion and metastases to the paracardial and mediastinal lymph nodes were observed, the esophageal submucosal tumor was considered to be an intramural metastasis from the carcinoma of the gastric cardia resulting from extensive lymphatic spread. The patient died of recurrent disease 9 months after the resection. This case report serves to demonstrate that intramural metastasis may be a local indicator of the systemic spread of disease in patients with gastric carcinoma, as it is in esophageal carcinoma.

Adenocarcinoma↗

PubMed1998

Haemagglutinin-esterase protein (HE) of murine corona virus: DVIM (diarrhea virus of infant mice).

The acetylesterase (AE) activity of DVIM (diarrhea virus of infant mice) was assigned to the haemagglutinin-esterase (HE) protein. The substrate specificity was examined using the natural substrate bovine submaxillary mucin (BSM) and/or synthetic substrates p-nitrophenylacetate (p-NiA) and alpha-naphthylacetate (alpha-NA) and compared with several strains of MHV and influenza viruses. The AE of DVIM hydrolyzed the O-acetylester bond of BSM, and the two synthetic substrates p-NiA and alpha-NA in vitro. MHV-S reacted efficiently with both p-NiA and alpha-NA but less with BSM. Influenza virus (C/Miyagi/77) reacted with BSM efficiently, however reacted with p-NiA weakly, but not with alpha-NA at all. Thus, the AE-reactivity of DVIM was distinctly different from that of MHV-S and influenza C virus, suggesting that the AE of HE may have a modified function. Isolation of HE by the treatment with non ionic detergent NP40, resulted in globules approximately 5 nm in diameter. DVIM-binding proteins were demonstrated in the plasma membrane of mouse intestinal brush-border cells and hepatocytes. The same protein was recognized by MHV-S and MHV-4. The cell membranes obtained from these target tissues were substrates for the AE of DVIM. The biological importance of the HE protein for DVIM is discussed.

Acetylesterase↗

PubMed1998

Characterization of haemagglutinin-esterase protein (HE) of murine corona virus DVIM by monoclonal antibodies.

We analyzed the characteristics of seven monoclonal antibodies (mAbs) raised against purified HE (hemagglutinin-esterase) glycoprotein of the murine coronavirus DVIM (diarrhea virus of infant mice). Immunocrossreaction of these mAbs with JHM and/or MHV-S suggest that antigenic epitopes of HE of DVIM are similar to those of JHM and/or MHV-S. Four mAbs (1b4, 3a28, 4c19, 10b7), designated as group A mAbs, strongly inhibited both HA and AE activities. On the other hand, three mAbs (5a3, 6a6, 13a4), referred to as group B, had a comparatively weak HA inhibition activity. These results indicate that the antigenic epitopes of this glycoprotein can be classified into at least two groups and that the functional sites of HA and AE activities are similar but not identical. Neutralizing activity was shown in group A mAbs exclusively, suggesting that the ratio of HA and/or AE activities may play important roles in the cell fusion activity of DVIM-infected cells.

Animals↗

PubMed1998

Expression of tissue factor in the rabbit aorta after balloon injury.

Tissue factor (TF) is a primary initiator of the extrinsic pathway of blood coagulation. Recently TF has been shown to be overexpressed in atherosclerotic lesions and it is thought to contribute to the thrombogenicity of the plaques. We studied TF expression in the media and the neointima of rabbit aortas at various intervals after balloon injury. TF protein was immunohistochemically detected in smooth muscle cells (SMCs) of the inner layer of the media at 2 h after injury and was subsequently detected in SMCs in the neointima, whereas no TF expression was detected in the uninjured aortas except for the adventitia. Immunohistochemical and immunoelectron microscopic studies revealed that TF-positive SMCs were of an immature or synthetic phenotype and TF protein was detected in the rough endoplasmic reticulum in SMCs. TF mRNA in the intima and media increased at 2 h after injury and returned to near baseline levels at 12-24 h, whereas TF activity also increased at 2 h and continued at similar levels over the next 72 h. TF mRNA and activity increased markedly at 2-8 weeks after injury. These data suggest that TF is rapidly induced in the medial SMCs and hereafter is constitutively expressed in the neointima. TF expressed in the neointima may contribute to hypercoagulable properties of injured arteries.

Animals↗