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Biomedical subjects

S Ichikawa

Publications and source records attributed to S Ichikawa.

At least 343 records · Page 19Linked to original sources

Determination of horseradish peroxidase concentration using the chemiluminescence of Cypridina luciferin analogue, 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin-3-one.

The chemiluminescence of the Cypridina luciferin analogue, 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[1,2-a]pyrazin++ +-3-one (MCLA) was observed at 462 nm in the presence of horseradish peroxidase (HRP) and the total spectrum of light emitted was found to depend linearly on HRP concentration. Methods for the determination of HRP concentration using the chemiluminescence was investigated. HRP could be detected in the range from 100 pmol/L to 100 nmol/L under the optimum condition, H2O2 (10 mmol/L) and MCLA (10 mumol/L) at pH 5.8.

Animals↗

Adrenal endothelial cyst with massive central calcification.

A 55-year-old woman was treated for a rare case of adrenal endothelial cyst that was detected incidentally during management of abdominal pain. Computed tomography of the tumor displayed massive central calcification and a fluid-fluid level by intracystic hemorrhage. Magnetic resonance imaging showed an intracystic papillary part with calcification. After surgery, the tumor was diagnosed as an angiomatous type of adrenal endothelial cyst.

Adrenal Gland Diseases↗

Suprarenal inferior vena cava filter placement prior to transcatheter arterial embolization (TAE) of a renal cell carcinoma with large renal vein tumor thrombus: prevention of pulmonary tumor emboli after TAE.

To prevent embolization of necrotic renal vein tumor after transcatheter embolization of a left renal cell carcinoma, we placed a suprarenal Bird's nest inferior vena cava filter. The patient tolerated the procedure well and had extensive tumor infarction including the tumor thrombus on 6-month follow-up computed tomography.

Aged↗

Solitary hepatocellular carcinoma fed by the cystic artery: limitation of transcatheter arterial embolization.

PURPOSE: To clarify the limitations of transcatheter treatment for hepatocellular carcinoma (HCC) with parasitic feeders from the cystic artery. METHODS: Three male patients had a solitary HCC (average diameter 3 cm) fed by the cystic artery among 221 patients with HCC from 1994 to 1997. One tumor was nourished entirely from the cystic artery arising from the medial branch of the left hepatic artery, and two tumors were fed partially by the cystic arteries arising from the anterior inferior branch of the right hepatic artery. We analyzed the indications for transcatheter treatment for these three patients. RESULTS: We chose not to embolize the cystic artery for fear of necrosis of the gallbladder. Although embolization of the anterior branch of the right hepatic artery was performed in one patient with a tumor fed partially by the cystic artery, only half the tumor was embolized. Two patients underwent hepatic resection, and one received percutaneous ethanol injection therapy. At follow-up of 28-40 months (average 33 months) all patients are alive. CONCLUSION: Feeding by the cystic artery represents a limitation of TAE for HCC.

Adult↗

Interventional radiologic treatment for idiopathic portal hypertension.

PURPOSE: To evaluate the usefulness of interventional radiological treatment for idiopathic portal hypertension. METHODS: Between 1995 and 1998, we performed an interventional radiological treatment in five patients with idiopathic portal hypertension, four of whom had refused surgery and one of whom had undergone surgery. Three patients with gastroesophageal varices (GEV) were treated by partial splenic embolization (PSE), one patient with esophageal varices (EV) and massive ascites by transjugular intrahepatic portosytemic shunt (TIPS) and PSE, and one patient with GEV by percutaneous transhepatic obliteration (PTO). Midterm results were analyzed in terms of the effect on esophageal and/or gastric varices. RESULTS: In one woman with severe GEV who underwent three sessions of PSE, there was endoscopic confirmation that the GEV had disappeared. In one man his EV shrunk markedly after two sessions of PSE. In two patients slight reduction of the EV was obtained with one application of PSE combined with endoscopic variceal ligation therapy. PTO for GV in one patient resulted in good control of the varices. All patients have survived for 16-42 months since the first interventional treatment, and varices are well controlled. CONCLUSION: Interventional radiological treatment is effective for patients with idiopathic portal hypertension, whether or not they have undergone surgery.

Adult↗

Inhibition of herpes simplex virus infection by tannins and related compounds.

Several chemically defined plant extracts were investigated for their antiviral action on herpes simplex virus (HSV-1, HSV-2)-infected African green monkey kidney cells and human adenocarcinoma cells, using a plaque formation assay. Among them, the monomeric hydrolyzable tannins, oligomeric ellagitannins and condensed tannins, having galloyl groups or hexahydroxydiphenoyl groups, had the most potent anti-HSV activity. Their 50% effective doses (0.03-0.1 microgram/ml) were by two-three orders of magnitude lower than their 50% cytotoxic doses (greater than 10 micrograms/ml). On the other hand, gallic acid, neutral polysaccharides, chemically modified (N,N-dimethylaminoethyl-, carboxymethyl-, and sulfated-) glucans, sialic acid-rich glycoproteins, and uronic acid-rich pine cone polysaccharide showed little or no activity. Using radiolabeled virus particles, we demonstrated that the anti-HSV effect of the tannins is due to inhibition of virus adsorption to the cells.

Adsorption↗

Blood trauma induced by clinically accepted oxygenators.

Hemolysis remains one of the most serious problems during cardiopulmonary bypass (CPB), extracorporeal membrane oxygenation (ECMO), and percutaneous cardiopulmonary support (PCPS). However, the hemolytic characteristics associated with oxygenators are not well defined. A specialized hemolysis test protocol for oxygenators was developed. A comparative study was performed following this protocol to determine the hemolytic characteristics of the clinically available oxygenators during CPB; pressure drop measurements in the blood chamber were also performed. Four oxygenators (Medtronic Affinity, Cobe Optima, Terumo Capiox SX25, and Bard Quantum) were evaluated. Fresh blood from healthy Dexter calves anticoagulated with citrate phosphate dextrose adenine solution was used. The blood flow was fixed at 5 L/min, similar to that used in CPB. The Normalized Index of Hemolysis for Oxygenators (NIHO) has been modified according to the American Society of Testing and Materials (ASTM) standards. The NIH value, which was obtained from the circuit without an oxygenator, was subtracted from the primary NIH value, obtained from the circuit with an oxygenator to eliminate the effects of a centrifugal pump or other artifacts. The NIHO value was the lowest in the Affinity (0.0116 +/- 0.0017) and increased from Affinity < Optima (0.0270 +/- 0.0038) < Capiox (0.0335 +/- 0.0028) < Quantum (0.0416 +/- 0.0015 g/100 L). The Optima and Capiox did not demonstrate a significant difference. In addition, this NIHO value has a close relationship to the pressure drop. In conclusion, this new evaluation method is suitable to compare the biocompatibility performance of different types of clinically available oxygenators for CPB usage.

Animals↗