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Biomedical subjects

S Usui

Publications and source records attributed to S Usui.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Photodynamic diagnosis and photodynamic therapy for experimental hepatoma with ME 2906].

We studied the effects of photodynamic diagnosis (PDD) and photodynamic therapy (PDT) in confirming the existence of hepatoma, using the new photosensitizer mono-L-aspartyl chlorine 6. Japanese white rabbits were selected for abdominal incision under intravenous anesthesia, and VX 2 tumor cells were transplanted into the left liver lobe to create a hepatoma model. In the experiment, hepatoma of 1 cm in diameter (at one week after transplantation) was radiated with a semiconducter laser (664 nm, 200 J/cm2) for treatment.

Animals↗
PubMed2000

Retinal changes after retinal translocation surgery with scleral imbrication in dog eyes.

PURPOSE: To examine retinal changes induced by scleral imbrication during retinal translocation surgery in dog eyes. METHODS: Fifteen dogs were anesthetized and underwent retinal translocation surgery. After lensectomy and vitrectomy, an intentional retinal detachment was created, and the upper temporal sclera around the equator was imbricated with five mattress sutures. Translocated distances were calculated by pre- and postoperative photographs. At 1, 2, and 4 weeks after the surgery, the retina was studied by TdT-dNTP terminal nick-end labeling (TUNEL) and immunohistochemistry of peanut agglutinin (PNA) lectin and glial fibrillary acidic protein (GFAP). RESULTS: The retina was translocated by a mean distance of 0.53 +/- 0.30 disc diameters or 959 +/- 543 micrometer. Retinal folds were created around the optic disc in all eyes. Histologic examination of the retinal folds 1 week after the surgery showed many TUNEL-positive cells in the outer nuclear layer, loss of photoreceptor cells, and shortening of the outer and inner segments. A strong immunoreactivity to GFAP was detected in the folds of the retina. CONCLUSIONS: . The results demonstrated that retinal translocation surgery by scleral imbrication inevitably caused retinal folds as a postoperative complication, and the retina within the folds showed extensive loss of photoreceptor cells. It is recommended that the foveal translocation surgery be planned to avoid involving the fovea in the retinal folds.

Animals↗
PubMed1999

The lower entrainable limit of rat circadian rhythm to sinusoidal light intensity cycles: a preliminary study.

The lower entrainable limit of the circadian behavioral rhythm was examined in rats exposed to sinusoidal light intensity cycles with maximum illuminance of 20 lux and the minimum of 0.01 lux. The period (T) of the light intensity cycle was initially kept at 23.5 h for 20 cycles, and then shortened to 23 h for 33 cycles. Thereafter the rats were released into constant darkness. Five out of 10 rats entrained their circadian rhythms to T = 23.5-h cycle, and they also entrained to the T = 23-h cycle. The phase angle of entrainment was almost unchanged when T was shortened from 23.5 h to 23 h. These results suggest that the T = 23-h cycle was close to the lower limit of entrainment.

Animals↗
PubMed1999

Purification of a growth-suppressing factor for bovine artery endothelial cells from mouse lymphoma P388D1 cells.

A growth-suppressing factor for bovine artery endothelial cells (BAEGSF) was purified from the conditioned medium of a mouse lymphoma P388D1 cell culture in the presence of 100 microg/ml carboxymethylated curdlan. The purification steps included, in order, ammonium sulfate fractionation and eight stages of column chromatography on Macro-Prep Ceramic Hydroxyapatite, Q-Sepharose, Sephacryl S-300 HR, Matrex PBA-30, CHT II, Resource-Q, anti-bovine serum albumin (BSA) agarose, and Superdex 200HR columns. The purified BAEGSF showed two bands with silver staining on a sodium dodecyl sulfate polyacrylamide gel under reducing conditions (SDS-PAGE) and their molecular weights were estimated as approximately 55 and 63 kDa, while the molecular weight of the purified BAEGSF was estimated as about 65 kDa by gel filtration using Superdex 200HR. This result shows that BAEGSF obtained from Superdex 200HR chromatography is a partially purified preparation and suggests that one of the two bands on SDS-PAGE corresponds to BAEGSF. BAEGSF was shown not to have a lethal effect on endothelial cells, but had an inhibitory action on the proliferation of these cells. Furthermore, the growth-suppressing activity of BAEGSF for bovine artery endothelial cells (BAE) was not inhibited by anti-transforming growth factor-beta (TGF-beta), anti-tumor necrosis factor-alpha (TNF-alpha), and anti-interleukin-1 (IL-1) antibodies. These results suggest that BAEGSF is different from TGF-beta, TNF-alpha, and IL-1 which have been reported to inhibit BAE growth.

Animals↗
PubMed1999

Growth suppressing factor for endothelial cells exhibits tumor regressing activity.

Endothelium growth suppressing and tumor-regressing activities were copurified from the conditioned medium of P388D1 culture in the presence of 100 microg/ml carboxymethylated curdlan by a procedure including ammonium sulfate fractionation and six column chromatographies of Ceramic hydroxyapatite, Q-Sepharose, Sephacryl S-300 HR, Matrex PBA-30, PBE94, and anti-bovine serum albumin (anti-BSA) agarose. The intravenous administration of the purified growth suppressing factor for endothelial cells to sarcoma 180-bearing mouse caused a rapid decrease in the number of viable tumor cells in tumor lumps within 16 h. Immunohistochemical study showed that the intravenous injection of the purified factor to sarcoma 180-bearing mouse resulted in hemorrhagic disorder all over the tissue in the tumor lamp. Thus, the purified factor exhibited not only growth suppressing activity for endothelial cells but also tumor regressing activity at a concentration as low as about 15 ng/mouse. The purified factor significantly inhibited in vitro tubulogenesis of bovine artery, human umbilical vein, and adult human darmal microvascular endothelial cells on collagen gel at a concentration of about 5 ng/ml. After the tube formation of endothelial cells was completed on a collagen gel, the purified factor disrupted the tubes at a concentration of about 5 ng/ml within 48 h. These findings demonstrate that endothelium growth suppressing factor is a potent inhibitor of angiogenesis as well as the growth of endothelial cells, and may bring about the regression of a solid tumor by inhibiting angiogenesis.

Adult↗
PubMed1999

Structural features and hypoglycemic activity of a polysaccharide (CS-F10) from the cultured mycelium of Cordyceps sinensis.

A polysaccharide (CS-F10) purified from a hot water extract of the cultured mycelium of Cordyceps sinensis was composed of galactose, glucose and mannose in a molar ratio of 43:33:24; its molecular weight was estimated to be about 15000. The results of chemical and spectroscopic investigations suggest that CS-F10 has a comb-type structure, and has alpha-D-glucopyranosyl residues on the terminal of the side-chains and characteristic sugar residues of C. sinensis i.e., 1,5-linked beta-D-galactofuranosyl residues. CS-F10 significantly lowered the plasma glucose level in normal, streptozotocin (STZ)-induced diabetic and epinephrine-induced hyperglycemic mice after intraperitoneal administration (50 mg/kg). Administration of CS-F10 to STZ-induced diabetic mice significantly increased the activity of hepatic glucokinase. A significant reduction in the hepatic glucose output was observed following the infusion of CS-F10 using the perfused rat liver. CS-F10 also significantly decreased protein content of facilitative glucose transporter isoform 2 (GLUT2) from rat liver following i.p. administration. These effects presumably contribute to the hypoglycemic activity.

Animals↗
PubMed1999

Activation of macrophages and neutrophils by an endothelium growth suppressing factor.

An endothelial cell growth-suppressing factor (EGSF) was purified from the serum-free conditioned medium of the mouse P388D1 culture in the presence of carboxymethylated curdlan. The purified EGSF showed two bands corresponding to the molecular masses of 55 and 63 kDa by silver staining on a SDS-polyacrylamide gel under reducing conditions. This factor strongly suppressed the proliferation of endothelial cells from bovine artery, human umbilical vein, and human dermal vas capillare and this suppression was observed to be reversible. We found that EGSF was a potent chemoattractant for macrophages and neutrophils. EGSF mediated the adhesion of neutrophils to BAEs and transendothelial migration of neutrophils. Macrophages stimulated by EGSF produced nitrite in a dose-dependent manner. EGSF did not affect the proliferation of T lymphocytes. These findings suggest that EGSF acts not only as a potent inhibitor for the growth of endothelial cells but also an activator for macrophages and neutrophils. Thus EGSF plays a role in an inflammatory response in the endothelium.

Animals↗
PubMed1999

[Treatment policy for colon cancer liver metastases].

Hepatectomy provides the highest rates of cure among the methods for treating colon cancer liver metastases, but it cannot be performed in many cases. Hepatectomy is the treatment of choice for colon cancer liver metastases in our department, but we conduct transcatheter arterial embolization alone or in combination with MCT on patients in whom hepatectomy cannot be performed or those with residual tumor following hepatectomy. Transcatheter arterial embolization is conducted on patients shown to have tumor vessels, following a single intra-arterial shot of an anticancer drug. MCT is performed under general anesthetic percutaneously or by abdominal section in patients who have not responded well to transcatheter arterial embolization, in order to improve the effectiveness of treatment on the tumor overall. We consider the combination of transcatheter arterial embolization and MCT to be an effective treatment for patients with a colon cancer liver metastasis who present with tumor vessels.

Aged↗
PubMed1999

[An analysis of the cardiovascular responses under hyper- and hypo-gravity environments using a mathematical model].

Gravity affects cardiovascular control system remarkably. Internal control mechanism responsible for such cardiovascular changes under hypo- and hyper-gravity have not yet been fully understood, although many biological and physiological measurements as to cardiovascular system have been conducted since man's first exploration to space. One reason for this arises from the difficulty in continuous and simultaneous measurements of hemodynamics of many parts of the body. To overcome this difficulty, a mathematical model was constructed based on animal and human physiological evidence in our previous study. In the present study, the model is used for explaining hemodynamics during hyper- and hypo-gravity environments obtained during parabolic flight. The parabolic flight experiment was conducted by a small rear-jet MU300. Three university male students volunteered as subjects. Five to eleven parabolic flights per day were performed for 6 days. The subjects sat on a chair either in an upright position or a 45 degree reclining position. Electrocardiogram and finger blood pressure were measured continuously during the flights. Variable parameters of the model were adjusted so that heart rate and blood pressure of the model fit to those of the experiment. It was shown that the model can quantitatively reproduce and predict experimental heart rate and blood pressure during a parabolic flight. Analysis of internal property of the model revealed hemodynamics of the human cardiovascular system during a parabolic flight which explains the mechanisms of cardiovascular responses under hyper- and hypo-gravitational environments.

Blood Pressure↗
PubMed1998

Quantitative detection method of triglycerides in serum lipoproteins and serum-free glycerol by high-performance liquid chromatography.

We have developed a simple and reliable method for quantitative detection of triglycerides (TG) in serum lipoproteins and serum-free glycerol (FG) by high-performance liquid chromatography (HPLC). After separation of serum constituents using a new gel-permeation column (TSK gel Lipopropak XL, Tosoh) and a new eluent (TSK eluent LP-2, Tosoh), TG and FG were detected by on-line reaction using a modified reagent which contained glycerol kinase, glycerol-3-phosphate oxidase and lipoprotein lipase. HPLC patterns showed five peaks corresponding to chylomicrons, very-low-density, low-density, high-density lipoproteins and FG. Absolute concentrations of TG in each lipoprotein fraction and serum FG were calculated from the corresponding peak areas using standard FG as a calibrator. Due to its very high sensitivity of peak detection, this method has become desirable for the analyses of lipoproteins of very low concentrations such as in cell culture systems. This technique will contribute to a better understanding of lipoprotein TG and serum FG distribution in human and nonhuman subjects.

Animals↗
PubMed1998

Blood-nerve barrier in IgM paraproteinemic neuropathy: a clinicopathologic assessment.

We report the pathologic findings in a patient with sensorimotor neuropathy associated with Waldenström's macroglobulinemia, particularly in relation to blood-nerve barrier defects. The monoclonal IgM was of kappa type and possessed anti-HNK-1 activity. A sural nerve biopsy specimen revealed severe loss of myelinated and unmyelinated nerve fibers and gaps between adjacent endothelial cells of small endoneurial vessels. Postmortem findings 3 years later included severe loss of myelinated nerve fibers and diffuse infiltration by lymphoplasmacytic B cells throughout the peripheral nervous system, sparing the central nervous system. Findings in this case suggest an immune attack against endoneurial endothelial cells with permeation of IgM into peripheral nerve tissue.

Aged↗
PubMed1998

Biological activities of (1-->3)-beta-D-glucans with reducing glucose side chains.

Newly synthesized (1-->3)-beta-D-glucans with reducing glucose side chains (6-O-glucopyranosylated curdlan and 3-O-glucopyranosylated curdlan, with glucose linked directly (except for anomeric carbon) had antitumor activity against mice sarcoma 180 in mice. The two glucans potentiated the reticuloendotheliai system and activated macrophages (increased their glucose consumption). The activity inducing tumor regressing factor of the glucan derivatives was stronger than a linear (1-->3)-beta-D-glucan (curdlan).

Animals↗
PubMed1998

[Progress of enteral nutrition].

Intravenous hyperalimentation and enteral nutrition are the main surgical nutrition methods. IVH play an active role in therapeutic nutrition, although made rapid progress has been made in enteral nutrition, resulting in its wide clinical application. Branched-chain amino acids are useful in improving the nitrogen balance in patients who have undergone major surgical procedures or significant stress. Furthermore, their superiority over a mixed oral protein diet in patients with hepatic encephalopathy has been confirmed clinically. Medium-chain triglycerides (MCT) are an important energy source. Their advantages include easy absorbtion by the intestinal mucosa, lack of stimulation of insulin excretion, and suppression of the reticuloendothelial system. However, the ratio of long-chain triglyceride (LCT) to MCT should be evaluated in many cases. EPA can prevent various adult diseases. Many nutrients contain EPA and it is clinically used both enterally and parenterally. Glutamine is effective in the repair of small intestinal mucosal damage, since it suppresses bacterial translocation, effects of growth hormone, epidermal growth factor (EGF), and nucleic acid on nutritional status are being evaluated clinically. Home enteral nutrition (HEN) has become more common in the past five years although close, cooperation between medical staff and the family is necessary its success.

Adult↗
PubMed1998

[A basic study of photodynamic therapy of experimental hepatoma with ME 2906].

We have studied effects of photodynamic diagnosis (PDD) and photodynamic therapy (PDT) in hepatoma as confirmed by the existence of hepatoma when using a new photosensitizer mono-L-aspartyl chlorin e6. Japanese white rabbits were selected to perform abdominal incision under intravenous anesthesia and transplant VX2 tumor cells into the liver left lobe for the hepatoma model. Hepatoma of 1 cm in diameter (at one week after transplantation) was used experimentally to radiate a semiconductor laser (664 nm, 200 J/cm2) for treatment.

Animals↗
PubMed1997

Polysaccharides in fungi. XXXVIII. Anti-diabetic activity and structural feature of a galactomannan elaborated by Pestalotiopsis species.

A fungus of Pestalotiopsis species produced an extracellular, water-soluble polysaccharide (PS-N). PS-N exhibited significant hypoglycemic activity in streptozotocin-induced diabetic mice following intraperitoneal administration and had an effect on oral glucose tolerance in normal mice following oral administration. PS-N ([alpha]D +34.5 degrees in water) was homogeneous on gel chromatography, it is composed of galactose and mannose in a molar ratio of 1:9, and its molecular weight was estimated by gel chromatography to be about 24,000. Its structure was investigated by a combination of chemical and spectroscopic methods. The results indicated that PS-N, a highly branched galactomannan, is composed of beta-(1-->3)-linked D-galactofuranosyl and non-reducing terminal beta-D-galactofuranosyl residues, in addition to alpha-D-mannopyranosyl residues of a yeast mannan type.

Animals↗
PubMed1997

Preparation of novel (1-->3)-beta-D-glucans having reducing glucose side chains.

Novel (1-->3)-beta-D-glucans (GPBCD, GPECD, GP6CD, and GP3CD) having reducing glucose side chains were prepared from a linear (1-->3)-beta-D-glucan (curdlan: CD) with halogeno glucose isopropylidene derivatives in dimethyl sulfoxide containing dimsyl sodium, followed by treatment with 40% trifluoroacetic acid to remove protecting isopropylidene groups. The side chain glucose moiety was linked or directly or through a spacer at various positions except for its anomeric carbon.

Carbohydrate Conformation↗
PubMed1997

Growth suppressing activity for endothelial cells induced from macrophages by carboxymethylated curdlan.

A carboxymethylated derivative of a linear (1-->3)-beta-D-glucan (CMCD) from Alcaligenes faecalis var. myxogenes acted directly on mouse peritoneal macrophages and mouse lymphoma P388D1 cells, and induced a growth suppressing activity for bovine artery endothelial cells (BAEs) from themselves at a concentration of 100 micrograms/ml. The suppressing activity was also detected in the mouse serum administered as an i.p. injection of CMCD at a dose of 100 mg/kg, suggesting that the growth suppressing activity was induced from macrophages potentiated by CMCD in vivo.

Animals↗