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Biomedical subjects

K Kusaka

Publications and source records attributed to K Kusaka.

At least 37 records · Page 2Linked to original sources
PubMed1999

Portal venoplasty for recipients in living-related liver transplantation.

BACKGROUND: In living-related liver transplantation (LRLT) in small children, standard end-to-end portal vein (PV) anastomosis is usually difficult because of a inadequate total PV length, or because of a size mismatch between the graft and the recipient PV. In this report, we present our new portal venoplasty technique for the recipient PV. METHODS: After dissection of the recipient PV, the wall between the right and left branches of the PV is severed longitudinally as in the branch patch technique. The anterior and posterior edges of both branches are joined using running sutures, to form a longer and wider PV for anastomosis. RESULTS: This new portal venoplasty technique was used in 7 of 28 child cases, and gave good results without thrombosis or other complications. CONCLUSIONS: Our new portal venoplasty technique is useful in LRLT in small children when the recipient or graft PV is not long enough.

Adult↗
PubMed1998

Risk factors for hyperamylasemia after hepatectomy using the Pringle maneuver: randomized analysis of surgical parameters.

OBJECTIVES: To determine whether the increased portal venous pressure caused by use of the Pringle maneuver contributes to inducing posthepatectomy hyperamylasemia and, subsequently, to evaluate risk factors for its development. DESIGN: Randomized study. SETTING: University hospital. PATIENTS: Forty patients who were going to undergo hepatectomy were assigned prospectively to either a superior mesenteric artery clamp (n=20) or a nonclamp (n=20) group by the random-block method. INTERVENTIONS: The Pringle maneuver was used during hepatectomy, and in the superior mesenteric artery clamp group the superior mesenteric arteries were clamped simultaneously. MAIN OUTCOME MEASURES: Amylase activity, isozyme, and creatinine levels in the blood and urine samples were measured before and after surgery, and the amylase creatinine clearance ratio was estimated. RESULTS: The serum amylase activity levels of the superior mesenteric artery clamp and nonclamp groups did not differ significantly during the 7 postoperative days. The serum amylase activity levels exceeded 250 U/L in 14 patients (group 1) and remained below this level in 26 (group 2). The salivary-type isozyme levels of group 1 increased significantly compared with those of group 2, and the levels of group 2 remained normal. The total amount of amylase excreted in the urine samples of group 1 patients also increased significantly, with the salivary-type isozyme predominating. All the mean amylase creatinine clearance ratios before and after surgery remained normal. The mode chi2 of the logistic model including the indocyanine green retention rate at 15 minutes and the ratio of the resected liver weight to the whole liver volume showed a significantly increased risk (P=.01). CONCLUSION: It is not the increased portal venous pressure caused by use of the Pringle maneuver but the liver function and the extent of liver resection that are considered risk factors for inducing posthepatectomy salivary-type hyperamylasemia.

Aged↗
PubMed1998

Modulation of basic fibroblast growth factor effect by retinoic acid in cultured retinal pigment epithelium.

PURPOSE: We investigated the effect of retinoic acid (RA) on basic fibroblast growth factor (bFGF)-stimulated proliferation of cultured human retinal pigment epithelial (hRPE) cells and of 125I-bFGF-binding to the bFGF plasma membrane receptors of hRPE. METHODS: Proliferation of hRPE cells in the presence of increasing concentrations of bFGF and bFGF + RA was measured by 3H-thymidine incorporation into hRPE cells. To characterize bFGF receptors, hRPE cells were incubated at 4 degrees C with 125I-bFGF in the presence or absence of heparin. RESULTS: Basic-FGF stimulated 3H-thymidine incorporation into hRPE cells in a dose-dependent manner. RA inhibited bFGF-stimulated 3H-thymidine incorporation in the presence or absence of heparin. Increasing concentrations of unlabeled bFGF decreased the binding of 125I-bFGF to hRPE cells. Scatchared analysis indicated the presence of high and low affinity binding sites for bFGF with an apparent affinity Kd of 50 pM and 330 pM, respectively, and a binding capacity (Bmax) of 1.25 X 10(5) and 3.38 X 10(5) binding sites per cell. Inhibition of 125I-bFGF binding was also possible by the carboxyl-terminal region peptide fragment bFGF-(106-120)-NH2, but not amino-terminal region peptide fragment bFGF-(1-24)-NH2. The addition of heparin to the medium during binding studies did not prevent RA from inhibiting binding of 125I-bFGF to hRPE cells. Scatchard analysis demonstrated that, in the presence of heparin, there is a decrease in the number of high affinity binding sites (from 1.12 +/- 0.11 x 10(5) to 0.7 +/- 0.03 x 10(5) binding sites per cell, a reduction of 36.7 +/- 0.04%, n = 3, p < 0.05). There was no significant change in affinity constants. CONCLUSIONS: These results suggest that RA inhibits bFGF cell proliferation in hRPE cells by decreasing the bFGF receptor number.

Binding Sites↗
PubMed1997

Measurement of liver volume and hepatic functional reserve as a guide to decision-making in resectional surgery for hepatic tumors.

The respective volumes of hepatic tumors and nontumorous parenchyma of 50 patients requiring hepatectomy of more than one segment of Healey for tumor removal were measured using computed tomography (Vol-CT). The volume estimated by Vol-CT was found to correlate with the real weight resected (P < .0001) with a mean absolute error of 64.9 mL. The ratio of the nontumorous parenchymal volume of the resected liver to that of the whole liver (R2) in 15 patients who underwent right or extended right hepatic lobectomy was 43% +/- 15%. Eight of 15 patients with R2s < 60% underwent the procedures without right portal vein embolization (PE). The other seven with R2s exceeding 60% or an indocyanine green retention rate after 15 minutes (ICG15) of 10% to 20% underwent PE: in six of seven, the nontumorous parenchyma of the right hepatic lobe became atrophic and in all seven, the volume of the remaining left hepatic lobe increased with a decrease in the mean R2 from 62% +/- 14% to 55% +/- 8% (P = .0006). In the remaining 35 who underwent other hepatectomy procedures, R2s also remained <60%. Overall, at surgery, in 27 with normal liver function (ICG15 < 10%), R2s exceeded 60% in one, remained at 50% to 60% in five, and <50% in 21, whereas 23 patients except for one with an ICG15 exceeding 10%, had R2s of <50%. The postoperative serum total bilirubin levels in 84% of the patients remained within the normal range and there was no surgery-related mortality. In conclusion, 1) Vol-CT can accurately assess the extent of liver resection, 2) individuals with normal liver function can undergo resection of up to 60% of the nontumorous parenchyma without the need for PE, and 3) PE can be used to reduce the size of the resected tissue and increase the volume of the remnant liver to approximate the target limits in individuals with large tumors or minimally abnormal liver function.

Aged↗
PubMed1997

Isolation and characterization of Enterobacter cloacae mutants which are defective in chemotaxis toward inorganic phosphate.

Enterobacter cloacae IFO3320 is attracted to Pi when cells are starved for Pi. Two Tn1737KH-induced mutants, which were constitutive for alkaline phosphatase, failed to exhibit Pi taxis even under conditions of Pi limitation. Both of the mutant strains exhibited normal chemotactic responses to peptone, suggesting that they are specifically defective in Pi taxis. Cloning and sequence analysis showed that the TN1737KH insertions were located in either the pstA or pstB genes which encode the channel-forming proteins of the Pi-specific transport (Pst) system in E. cloacae. These results suggest that the E. cloacae Pst system is required for Pi chemoreception.

ATP-Binding Cassette Transporters↗
PubMed1997

A novel acid phosphatase from Aspergillus niger KU-8 that specifically hydrolyzes C-6 phosphate groups of phosphoryl oligosaccharides.

We had analyzed the detailed structures of the phosphoryl oligosaccharide-1 (PO-1) fraction that was the main component of phosphoryl oligosaccharides (POs) prepared from a potato starch hydrolysate. PO-1 fraction was made up of 3-phosphoryl oligosaccharides and 6-phosphoryl oligosaccharides. Aspergillus niger strain KU-8 produced two types of intracellular acid phosphatase (EC 3.1.3.2, ACPase); ACPase I and II. ACPase II preferentially dephosphorylated 6-phosphoryl oligosaccharides rather than 3-phosphoryl oligosaccharides. The molecular weight of the enzyme was estimated as 66 kDa by SDS-polyacrylamide gel electrophoresis and about 260 kDa by gel filtration, implying the active form to be a tetramer. The optimum pH and temperature of the enzyme were 2.0-2.5 and 60 degrees C, respectively. ACPase II was stable below 50 degrees C for 30 min and pH 2.0-10.0 for 60 min. In spite of the strict specificity toward 6-phosphoryl oligosaccharides in the PO-1 fraction, ACPase II was able to hydrolyze Fru-1,6-di-P, ATP, pyrophosphate, and polyphosphate as well as pNPP and Glc-6-P, a broad substrate specificity.

Acid Phosphatase↗
PubMed1995

Inhibitory effect of phosphorylated oligosaccharides prepared from potato starch on the formation of calcium phosphate.

The inhibitory effect of phosphorylated oligosaccharides, which were prepared from potato starch, on the formation of calcium phosphate in vitro were investigated. Phosphorylated oligosaccharides from potato were fractionated by ion-exchange chromatography into two fractions, PO-1 and PO-2. Fraction PO-1 was composed of maltotriose, maltotetraose, and maltopentaose to which one phosphate group was attached. Fraction PO-2 was predominantly composed of maltopentaose and maltohexaose to which at least two phosphate groups were attached. The average degree of polymerization of dephosphorylated PO-1 and PO-2 was evaluated to be 4.02 and 5.82, respectively. Fraction PO-2 was the main component having an inhibitory effect on calcium phosphate formation. In addition, among the phosphorylated monosaccharides, glucose-1,6-diphosphate and fructose-1,6-diphosphate were more effective inhibitors of the formation of calcium phosphate than glucose-6-phosphate and fructose-6-phosphate. These results suggest that the strength of the inhibitory effect might depend on the number of phosphate groups attached to each sugar molecule.

Calcium↗
PubMed1995

[Choroidal neovascularization with indocyanine green infrared fluorescence angiography and vascular cast preparation].

Indocyanine green infrared fluorescence angiography (ICG angiography) was compared with the fluorescein angiography (FAG) to evaluate its benefit. Experimentally induced choroidal neovascularization (ChNV), by laser photocoagulation of monkey eyes was studied by means of cast preparation correlating with findings of ICG angiography. FAG could detect ChNV more clearly than ICG angiography. However, some (2/35 sites) ChNVs with subretinal hemorrhage could be detected only with ICG angiography. In the early phase, the densely distributed part or thick vessels of ChNV could be detected with ICG angiography. On the other hand, the loose part could not be detected. Cast preparation did not show morphologic difference between leaky and non-leaky lesions with ICG angiography. These results showed that ICG angiography could not produce clearer results than FAG. However, ChNVs covered with subretinal hemorrhage could be detected only with ICG angiography. ICG angiography has complementary value in conjunction with FAG in order to detect ChNVs.

Animals↗
PubMed1995

Congenital deficiency of histidine-rich glycoprotein: failure to identify abnormalities in routine laboratory assays of hemostatic function, immunologic function, and trace elements.

Histidine-rich glycoprotein (HRGP) has many biologic activities, but its physiologic function is still unclear. To show the physiologic function of HRGP, we studied five patients with congenital HRGP deficiency. Hemostatic screening tests, activities of natural anticoagulants and fibrinolytic proteins, markers of thrombin and plasmin generation, plasma levels of platelet-specific proteins, thrombin times with various concentrations of bovine thrombin, prolongation of thrombin time after addition of heparin or demartan sulfate, and contact activation of blood coagulation were normal or nearly normal in these patients. Serum concentrations of immunoglobulin, functional activity of the classical and the alternative pathway of complement, lymphocyte subsets, and serum concentrations of soluble interleukin-2 receptor were approximately normal in all patients, and serum concentrations of copper and zinc were completely normal. These results suggest that the physiologic functions of HRGP are limited when compared with its biologic activities. However, because the patients examined had plasma HRGP levels of 20% to 35% of normal, it is possible that 20% of normal HRGP level is sufficient for its physiologic functions.

Antigens, CD↗
PubMed1994

[Thallium-201 single photon emission computed tomography in the evaluation of therapeutic response for brain tumors].

To evaluate the effectiveness of radiation and chemotherapy of malignant brain tumors, 201TlCl-SPECT (Tl-SPECT) was compared with CT and MRI. The subjects were 14 patients with malignant brain tumors; 12 malignant astrocytomas, 1 medulloblastoma and 1 malignant lymphoma. Tl-SPECT was performed before and immediately after the therapy. On the Tl-SPECT, count ratio (Tl-index) of tumor to normal brain tissue was measured. To evaluate the size of tumor, CT or MRI was performed before and immediately after the therapy, and 1-2 months after the therapy. The change of Tl-index immediately after therapy was compared with the change of the size of tumor. Though the change of Tl-index did not correlate with the change of tumoral size immediately after therapy, it correlated with the change of tumoral size 1-2 months after the therapy, i.e., it was thought that Tl-index reflected the change of tumoral size 1-2 months after the therapy. Tl-SPECT will be feasible for the evaluation of the effectiveness of the therapy for malignant brain tumors, because it reflects the effectiveness of the therapy earlier than CT or MRI.

Adult↗
PubMed1994

[An experimental study of diode laser photocoagulation and indocyanine green dye-enhanced diode laser photocoagulation in the primate retina].

A diode laser, emitting light in the near-infrared range (803 nm), was used for photocoagulation at mild, moderate, and strong intensities with or without intravenous administration of indocyanine green (ICG) in 7 eyes of 4 rhesus monkeys. The retinochoroidal lesions were studied histopathologically from 24 hours to 3 months after treatment, and choroidal vascular casts were studied by electron microscopy. Mild diode laser burns caused occlusion of the choriocapillaris and slight outer retinal damage. Moderate and severe burns caused more marked occlusion of the choriocapillaris, deep choroidal vessels, and choroidal nerves. There was little difference between ICG-enhanced and non-enhanced mild burns, but ICG-enhanced moderate and severe burns showed larger retinochoroidal lesions and more complete obstruction of the choriocapillaris than did burns without ICG enhancement. It seems that at moderate and strong levels, ICG-enhanced diode laser burns have more apparent effect on the retina and choroid, particularly on the choroidal vessels.

Animals↗
PubMed1993

[MRI findings and endocrinological dysfunction in hemorrhagic pituitary adenoma].

Magnetic resonance image (MRI) findings, intraoperative macroscopic findings and endocrinological functions were reported in 13 cases of hemorrhagic pituitary adenoma (HPA) according to clinical severity. The cases were divided into 3 groups: (1) classical pituitary apoplexy (PA) (n = 2), (2) subacute PA (n = 4), (3) asymptomatic HPA (n = 7). Based on MRI intensity and intraoperative findings, there were 7 cases with hemorrhagic PA and 5 with necrotic cyst formation. MRI intensities predicted the cyst contents, either hemorrhagic or xanthochromic, more accurately than CT findings. In addition, two classical cases of the PA group disclosed niveau formation on MRI, but MRI intensity in the first case differed from that in the second case. Classical PA of the first case occurred during the pregnancy. MRI intensity in the case 7 months after the onset disclosed high intensity of the upper part and normointensity of the lower part. T1 weighted image and proton image showed homogeneous intensity. On the contrast, PA of the second case showed water-like intensity on the upper part and methemoglobin-like intensity on the lower part. These different MRI intensities suggest different etiologies of niveau formation. MRI findings in the first case may indicate the chronic stage of massive intratumoral hemorrhage but the mechanism may be the same in both cases. From MRI intensity and clinical course, the cause of niveau formation in the second case is similar to that found in the literature. That is, hemorrhage was thought to have occurred in the pre-existing cyst cavity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenoma↗
PubMed1993

[Diagnostic vitrectomy for chronic uveitis].

Uveitis is diagnosed by ophthalmologic and systemic examination, but it may be difficult to diagnose accurately in some chronic cases. We performed diagnostic and therapeutic vitrectomy for chronic uveitis in 6 eyes of 4 patients, and examined vitreous specimens with immunohistochemical staining. Visual acuity improved in all cases due to clearing up of the vitreous cells. One patient had sarcoidosis, one had B cell malignant lymphoma (ocular reticulum cell sarcoma), and two had reactive lymphoid hyperplasia. Vitrectomy for chronic uveitis is useful for diagnosis and improvement of vision, and we recommend immunohistological staining of vitreous specimens. Particularly, when intraocular lymphoma is suspected, vitrectomy must be performed early.

Aged↗