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T Fukuzawa

Publications and source records attributed to T Fukuzawa.

At least 19 recordsLinked to original sources
PubMed2001

Hemodynamics in the left gastric vein after endoscopic ligation of esophageal varices combined with sclerotherapy.

BACKGROUND AND METHODS: We examined the changes in portal hemodynamics after endoscopic variceal ligation (EVL) combined with endoscopic injection sclerotherapy (EIS) in relation to post-treatment relapse. The present study included 93 patients who underwent EVL-EIS combination therapy. Portal hemodynamics were examined by Doppler ultrasonography and percutaneous transhepatic portography (PTP). RESULTS: Therapy with EVL-EIS resulted in the complete disappearance of varices in 89 of 93 patients. Cumulative relapse-free rates (Kaplan-Meier method) were 75.8 and 50.2%, respectively, 1 and 3-5 years after treatment. At the end of treatment, the flow in the left gastric vein was examined by Doppler ultrasonography. In 50 of 63 patients, the flow remained hepatofugal. In 23 of these patients, PTP was performed at the end of treatment; selective left gastric venography did not reveal any palisade zone vessels or varices. However, fine blood vessels were seen around the lower esophagus in nine patients, only the paraesophageal vein was found in 10 patients and these two findings were present in four patients, indicating that collateral blood flow remained in the lower esophagus in 13 of 23 patients. These findings suggest that frequent relapse of varices results from insufficient blockage of blood flow from the left gastric vein to the lower esophagus. However, in patients with a patent paraesophageal vein, long-term effects obtained by EVL-EIS combination therapy were satisfactory. CONCLUSIONS: The pattern of the development of collateral left gastric veins represents important hemodynamic changes that predict the long-term prognosis of patients after treatment.

Adult↗
PubMed2000

Melanophore lineage and clonal organization of the epidermis in Xenopus embryos as revealed by expression of a biogenic marker, GFP.

Melanophore lineage during embryogenesis of Xenopus laevis was traced using the overexpression of a biogenic marker, green fluorescent protein (GFP). Two different approaches were applied after injection of GFP mRNA (hence a marker construct) into each blastomere at the 16-cell stage. In in vivo experiments, the embryos injected with a marker construct were grown until stage 45, in which melanophores were distributed over the whole body and were good enough for checking GFP expression at their migratory destination. In in vitro experiments, neural tubes of the embryos injected with a marker construct were isolated and cultured at stage 21 to examine by virtue of GFP expression how neural crest cells differentiate into melanophores. The results obtained from both in vivo and in vitro experiments indicated the following: 1) selected animal blastomeres vastly contribute to the development of melanophores, whereas other animal blastomeres do so slightly at a limited pace; and 2) vegetal blastomeres never contribute to melanophores in normal development, whereas certain vegetal blastomeres have a potential to give rise to melanophores in vitro. The analyses using GFP also disclosed that the dorsal and ventral epidermis derive from the restricted animal blastomeres in the normal development. Since the dorso-ventrality of the epidermis has been inseparably coupled with integumental pigmentation, the clonal organization of the epidermis observed in the present study is discussed in the light of pigment pattern formation attributed by melanophores.

Animals↗
PubMed1998

White ball appearance in endoscopic ligation of bleeding esophageal varices.

BACKGROUND: Endoscopic variceal ligation is useful in the control of bleeding from esophageal varices. However, confirmation of ligation precisely at the site of bleeding is usually difficult when treating massive variceal bleeding. Characteristic endoscopic findings that appeared when ligation was performed at the site of bleeding are reported in this article. METHODS: Emergency endoscopic variceal ligation was performed in 14 patients with active bleeding from esophageal varices. Endoscopic findings after variceal ligation at the site of bleeding were compared with those at sites without bleeding. RESULTS: Active bleeding ceased just after endoscopic ligation at the site of bleeding in all patients. After ligation of the bleeding site of the varix, an unusual white-colored ball-like appearance (white ball appearance) was observed in all patients. This finding was markedly different from the purple-colored ball-like appearance that is usually observed after ligation of a varix at a site without bleeding. CONCLUSIONS: White ball appearance was a characteristic finding that appeared after ligation of a varix at the site of bleeding. This finding may be useful in the confirmation of successful ligation of a varix at its bleeding site.

Emergency Treatment↗
PubMed1997

The site and time of expression of MIF in frog development.

A ventrally localized melanization-inhibiting factor (MIF) has been suggested to play a role in the expression of dorsal-ventral pigment patterns in amphibia. Here we investigate the onset and localization of MIF appearance in frog development. The expression of MIF was analyzed in the wild-type and gray-eyed mutant (g/g) of Rana japonica by immunoblotting and immunohistochemistry using an anti-MIF neutralizing monoclonal antibody. Western blot analysis revealed that the anti-MIF antibody recognized approximately 51 kDa and approximately 58 kDa bands. The 51 kDa band first appeared at the external gill stage, while 58 kDa band was additionally detected at the hindlimb bud stage. With the use of immunohistochemistry, it was found that the anti-MIF antibody stained the whole epidermis of the embryos at the external gill stage; however, the staining was stronger in lateral and ventral epidermis than in dorsal. Staining with the anti-MIF antibody was observed only in the outer epidermis of the ventral skin, but not in the dorsal skin during and after metamorphosis. The spatial expression of MIF in the wild-type was the same as that in the gray-eyed mutant. The same immunohistochemical result was obtained in the adults of R. nigromaculata. These results suggest that MIF is involved in the formation of the dorsal-ventral pigment pattern.

Animals↗
PubMed1995

Evidence that MIF plays a role in the development of pigmentation patterns in the frog.

A ventrally localized melanization-inhibiting factor (MIF) may play an important role in the expression of dorsal-ventral pigment patterns of amphibians. In efforts to purify this putative MIF, ventral skin conditioned medium (VCM) from Rana forreri was partially fractionated and used to immunize mice. A monoclonal antibody that has the ability to block the activity of MIF was isolated, and an immunoaffinity matrix was prepared by cross-linking the antibody to protein G-Sepharose. The fraction of VCM that bound to the affinity matrix decreased the number of melanized cells in the Xenopus laevis neural tube explant assay, but did not reduce significantly the number of cells that emigrated. The monoclonal antibody was used for immunohistochemical studies on R. pipiens skin. Strong staining with the antibody was observed beneath the basement membrane, in mucous glands, and in the subcutaneous tissue of the ventral skin. A weak staining was also observed in the ground substances of both ventral and dorsal skin. These results confirm that a monoclonal antibody has been secured against at least one of the MIF constituents and that it is useful as a probe in detecting the distribution of MIF in tissues. The results of its use in this study support the hypothesis that MIF plays a role in the expression, development, and maintenance of the dorsal-ventral pigmentation patterns of frogs.

Animals↗
PubMed1995

Response of blood flow to vasopressin in the collateral left gastric vein in patients with portal hypertension.

BACKGROUND/AIMS: A problem in pharmacotherapy for bleeding varices in portal hypertension is non-responders. The aim of this study was to elucidate the features of hemodynamic response to vasopressin in the gastroesophageal collateral vein in patients with esophageal varices. METHODS: Flow velocity in the portal and the collateral left gastric vein was measured with an echo-Doppler flowmeter before and during infusion of vasopressin, 0.2 U/min, in 41 patients with cirrhosis and esophageal varices. RESULTS: The decrease in flow velocity in the left gastric vein with vasopressin (-29 +/- 25%) was significantly smaller than that in the portal vein (-56 +/- 20%). There was no or only minimal change in flow velocity in the left gastric vein in 39% of the patients, especially in those with large-size varices. In 28 patients examined by portal catheterization, changes in flow velocity in the left gastric vein were correlated with portal pressure, and portal pressure in non-responders was significantly higher than that in responders (non-responders: 363 +/- 49, responders: 312 +/- 41 mmH2O, p < 0.05). CONCLUSIONS: It was concluded that hepatofugal blood flow in the gastroesophageal collateral is not readily reduced by vasopressin. However, as the study was performed in a stable condition without variceal bleeding, whether these hemodynamic features will apply during acute variceal bleeding in patients who are known to have a poor hemodynamic response to vasopressin remains to be elucidated.

Aged↗
PubMed1995

N-CAM and N-cadherin are specifically expressed in xanthophores, but not in the other types of pigment cells, melanophores, and iridiphores.

Little is known about cell-cell communication in pigment cells, whereas a number of signalling molecules have been implicated to control their migration, differentiation, and proliferation. We set out to investigate the expression of cell adhesion molecules (CAMs) in the three different types of pigment cells in poikilotherms, Oryzias latipes and Xenopus laevis. In the present experiments, the expression of N-CAM and N-cadherin in the pigment cells in vitro was examined by immunocytochemistry. Melanophores and xanthophores were isolated and cultured from scales or skins, while iridophores were harvested from skins or peritoneum. The results showed that N-CAM and N-cadherin were specifically expressed in xanthophores, but not in melanophores or iridophores in both O. latipes and X. laevis. N-CAM and N-cadherin basically colocalized in the restricted regions of xanthophores, although the N-caderin-expressed region was broader than the N-CAM-expressed region in the same cell. The incidence of N-cadherin expression was higher than that of N-CAM expression. N-CAM and N-cadherin were expressed at the tip or the base of dendrites, or at the edge between dendrites in dendritic xanthophores. N-CAM and N-cadherin usually localized in small and narrow regions of xanthophores. This distribution pattern was essentially similar in xanthophores with round morphology, which exhibited spot, band, or semicircular immunoreactive regions on the peripheral edge of the cells. The difference in the distribution of pigment granules within the cells, culture period, fixatives, or immunofluorescent markers used in the experiments did not alter the immunostaining pattern.

Animals↗
PubMed1994

Fracture of the tibial tray following PCA knee replacement. A report of two cases.

We report two cases in which fracture of the tibial metal tray was thought to be due to improper design of the tray and heavy polyethylene wear. The bone beneath the fractured portion of the tray was deficient and had been replaced by granulomatous fibrous tissue including numerous polyethylene wear particles and foreign-body giant cells. Osteolysis occurred as a tissue reaction to these particles.

Aged↗
PubMed1994

[Ultrasonography in the diagnosis of liver cirrhosis].

Ultrasound is now widely used in the diagnosis of liver diseases. Applications of ultrasound in the diagnosis of liver cirrhosis are reviewed in this paper. Characteristic findings of liver cirrhosis in ultrasound are nodular liver surface, round edge, and hypoechoic nodules in liver parenchyma which represent regenerative nodules of cirrhotic liver. Detection of hypoechoic nodule more than 10 mm is important in the early diagnosis of hepatocellular carcinoma. Detection of splenomegaly, ascites, and portosystemic collaterals is possible by ultrasound. Evaluation of portosystemic collaterals is beneficial in the management of esophagogastric varices and portosystemic encephalopathy. Ultrasound is useful in the non-invasive diagnosis and long-term management of cirrhotic patients.

Ascites↗
PubMed1993

Cytoskeletal architecture of dermal chromatophores of the freshwater teleost Oryzias latipes.

Cytoskeletal construction of dermal chromatophores of Oryzias latipes was studied by immunofluorescence microscopy. A microtubule system was most prominent in melanophores where a large number of microtubules emanated from the center of the cell. Xanthophores had an arrangement basically similar to that of melanophores, though the radial pattern became more irregular in the peripheral region where intersecting wavy microtubules were quite frequent. Oval-shaped leucophores exhibited the least-developed microtubule system, where the limited number of microtubules formed a loose basket-like architecture. Intermediate filaments were ubiquitously present in all types of chromatophores and were found to be vimentin-immunoreactive. Examination of doubly-labeled cells indicated that vimentin filaments had similar distribution patterns with microtubules. Orderly arranged bundles of actin filaments were found only in xanthophores, while in melanophores and xanthophores, actin expression was diffuse without displaying a conspicuous filamentous organization. Colchicine treatment induced depolymerization of microtubules and retraction of dendrites in varying degrees in cells in culture and in situ. Melanophores in culture are very sensitive to the treatment while xanthophores appeared to be more resistant in respect to the maintenance of cell morphology.

Actins↗
PubMed1992

Kash et al. reply.

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Journal Article↗
PubMed1992

Intrinsic pigment cell stimulating activity in the skin of the leopard frog, Rana pipiens.

Consistent with the concept that specific pigment patterns of amphibians might result from the highly localized distribution of stimulators and inhibitors of pigment cell expression in the skin, the spot pattern of the leopard frog, Rana pipiens, was examined through the use of the Xenopus neural tube explant assay system (Fukuzawa and Ide, 1988). Media conditioned with pieces of skin from dorsal black spotted areas promoted melanization of neural crest cells at a significantly higher level than did media conditioned with dorsal interspot skin in the absence of extra tyrosine. All conditioned media contained exceedingly low concentrations of tyrosine. With the addition of supplemental tyrosine, the melanization capacity of conditioned media from the interspot areas was elevated to that of the spotted skin. Control media conditioned with ventral frog skin inhibited melanization, as usual, because of the presumed presence of melanization inhibiting factor (MIF). It is considered that dorsal skin contains a melanization stimulating factor (MSF) which is present in significantly higher levels in spotted skin than in interspot areas and that expression of the particular pigmentary pattern of this leopard frog is regulated by the relative distribution of MIF, MSF, and possibly other intrinsic substances present in the skin.

Animals↗
PubMed1992

Extracellular matrix constituents and pigment cell expression in primary cell culture.

Three types of pigment cells were isolated and cultured from larval Rana pipiens, and their attachment, maintenance, and proliferation were examined in the presence of extracellular matrix constituents (ECMs) in primary cell culture. The initial profile of pigment cell types present on day 2 of culture reflects the relative attachment of the cells to the dishes. Changes in the numbers of cells present after day 2 reflects the influence of factors present in the culture media on the maintenance, proliferation, or detachment of each type of pigment cell. Fetal bovine serum (FBS) promoted melanophore expression, but inhibited iridophore expression. FBS had no effect on xanthophores. In contrast, ventral skin conditioned medium (VCM), which contains melanization inhibiting factor, strongly stimulated iridophore expression, while it markedly inhibited melanophore expression. VCM had little effect on xanthophores. Of the ECMs tested, collagen type I had no effect on pigment cells. Fibronectin slightly inhibited melanophore expression, while it moderately stimulated iridophores and xanthophores. The stimulatory effect of fibronectin was not as strong as that of FBS or VCM. Laminin was also tested; however, it did not allow pigment cells to attach to the dishes, at least under the culture conditions utilized. The results of these experiments are discussed in terms of the general mechanisms of pigment pattern formation.

Animals↗