Effect of isosorbide dinitrate on nitric oxide synthase under hypoxia

Nitric oxide synthase (NOS) catalyzes nitric oxide (NO) formation from L-arginine in the presence of molecular oxygen and NADPH. NO is involved in the regulation of microvasculature. Isosorbide dinitrate (ISDN) and glyceryl trinitrate (GTN) have been widely used as vasodilators to treat acute myocardial ischemia, their biological effects being due to the release of NO. In this investigation, the effects of ISDN and GTN on NOS activity in the presence or absence of oxyhemoglobin under hypoxia and normoxia were studied. The apparent K(m) values for molecular oxygen were 21.6 +/- 1.5 and 9.4 +/- 1.3 micromol/l for nNOS and eNOS, respectively. ISDN liberated NO in a concentration- and pH-dependent manner, but no differences between hypoxia and normoxia were observed. The NO release from ISDN was also measured directly by an electron spin resonance spectral method with N-(dithiocarboxy)sarcosine-Fe complex as a NO-trapping agent. ISDN increased nNOS and eNOS activities in the presence of 30 micromol/l oxyhemoglobin under hypoxia, while it did not affect nNOS and eNOS activities under normoxia. In the absence of oxyhemoglobin, ISDN inhibited nNOS and eNOS activities under both hypoxic and normoxic experimental conditions. The rate of oxygen release from oxyhemoglobin under hypoxia was increased 3 times in the presence of 1 mmol/l ISDN. In contrast to ISDN, GTN could not release NO spontaneously, and it also did not affect nNOS and eNOS activities in the absence or presence of 30 micromol/l oxyhemoglobin under both hypoxic and normoxic conditions. These results indicated that the NO release from ISDN is different from that of GTN, and the increase of NOS activity by ISDN in the presence of oxyhemoglobin under hypoxia is ascribed to the increase in molecular oxygen concentration.     

Removal of Toxin (Tetrodotoxin) from Puffer Ovary by Traditional Fermentation

The amounts of puffer toxin (tetrodotoxin, TTX) extracted from the fresh and the traditional Japanese salted and fermented “Nukazuke” and “Kasuzuke” ovaries of Takifugu stictonotus (T. stictonotus) were quantitatively analyzed in the voltage-dependent sodium current (I_Na) recorded from mechanically dissociated single rat hippocampal CA1 neurons. The amount of TTX contained in “Nukazuke” and “Kasuzuke” ovaries decreased to 1/50–1/90 times of that of fresh ovary during a salted and successive fermented period over a few years. The final toxin concentration after fermentation was almost close to the TTX level extracted from T. Rubripes” fresh muscle that is normally eaten. It was concluded that the fermented “Nukazuke” and “Kasuzuke” ovaries of puffer fish T. Stictonotus are safe and harmless as food.     

An immunoradiometric assay of tumour-antigen 4 (TA-4): a comparison with conventional radioimmunoassay

The serum level of tumour-antigen 4 (TA-4) was measured in 181 patients with squamous cell carcinoma (SCC) of various organs (71 lung, 24 uterus, 16 oesophagus, 64 head and neck and six skin), 34 patients with other types of lung cancer and 35 patients with benign diseases. To compare the results with those obtained by the conventional competitive radioimmunoassay (RIA) using a polyclonal antibody, a new immunoradiometric assay (IRMA) method was used which has recently been developed using two monoclonal antibodies raised to different epitopes of TA-4. Both methods provided essentially the same results: the serum TA-4 levels were high in patients with SCC of various organs when compared with those of healthy controls and patients with other types of lung cancer or benign diseases. However, the positive ratios assessed as the percentage of patients with elevated serum TA-4 levels were higher with the IRMA method than with the RIA method in SCC of all organs, as much as 2-3 times higher in SCC of the larynx, tongue and pharynx. In contrast, in patients with benign diseases or other types of lung cancer, there was no difference in the positive ratios between the two methods. This was largely due to the improvement in sensitivity and accuracy of assay with the new method, which resulted in a decrease in the normal value in healthy controls. It was concluded that with the new IRMA method using monoclonal antibodies, the diagnostic detectability of serum TA-4 is enhanced in SCC of all organs.     

USEFULNESS OF MULTI DETECTOR ROW COMPUTED TOMOGRAPHY FOR DETECTION OF FLAT AND DEPRESSED COLORECTAL CANCER

Background: Recently, the clinical usefulness of colorectal cancer screening by CT colonography has been reported in Europe and the USA. However, in Japan, the diagnosis of flat or depressed colorectal cancer lesions has been emphasized, and the question of whether CT colonography facilitates visualization of these lesions remains to be answered. In the present study, we compared the visualization of flat and depressed colorectal cancer lesions by CT colonography with that of protruding lesions. Methods: We investigated 33 Dukes A colorectal cancer lesions that had been examined by 3D‐CT, colonoscopy, and barium enema prior to surgery. In all patients, CT colonography was performed immediately after colonoscopy. Volume rendering was used for 3‐D rearrangement, and imaging findings were examined with respect to morphology, tumor diameter, and tumor height. Results: All (14/14) of the protruding‐type lesions were visualized by CT colonography, whereas 78.9% (15/19) of the flat and depressed‐type lesions were visualized. There was no significant difference in tumor diameter between protruding‐type lesions and flat and depressed‐type lesions. With respect to tumor height, 100% of the lesions measuring 2 mm or more in height were visualized, whereas only 42.9% of those measuring less than 2 mm in height were visualized; the difference was significant (P < 0.001). Conclusions: These results suggest that the visualization capacity of CT colonography is associated with tumor height, but not with tumor diameter. Currently, lesions measuring 2 mm or more in height can be visualized reliably by CT colonography.     

MR imaging of adrenal masses smaller than 5 cm. Characterization with T2 relaxation time at 1.5 T]

The T2 relaxation times of 28 adrenal masses smaller than 5 cm obtained using a 1.5 Tesla MR imaging system were analysed to evaluate the ability of this parameter to characterize the tissue masses. The adrenal masses included 13 nonhyperfunctioning adenomas, five hyperfunctioning adenomas, five metastatic tumors, two pheochromocytomas, one nodular hyperplasia, one ganglioneuroma, and one cyst. The mean T2 value of nonhyperfunctioning adenomas was almost the same as that of hyperfunctioning adenomas. A significant difference was found in T2 (p less than 0.01) between nonhyperfunctioning adenoma (50 msec +/- 7 msec; mean +/- S.D.) and metastatic tumor (63 msec +/- 11 msec), whereas there was no significant difference in mass size between them. The two pheochromocytomas and the ganglioneuroma, which were derived from adrenal medulla, had relatively long T2 of over 70 msec. The T2 values of nodular hyperplasia and adrenal cyst were 58 msec and 123 msec, respectively. Although the T2 values of metastatic tumors tended to be longer than those of nonhyperfunctioning adenomas, differentiation between them with a T2 of 60 msec was not necessarily possible, especially in smaller masses. The T2 values of two metastatic tumors of less than 2 cm indicated 50 msec levels. There seemed to be a correlation between mass size and T2 in metastatic tumors. In adenomas, however, no significant correlation was demonstrated. We conclude that the characterization of small adrenal masses by T2 at 1.5 Tesla is unsatisfactory in differentiating metastatic tumors from nonhyperfunctioning adenomas.     

A Novel Method for Removal of Human Immunodeficiency Virus: Filtration with Porous Polymeric Membranes

We propose a new method to rid solutions of a virus by using a novel regenerated multilayered structured cellulose membrane (BMM). When the filtrate of human immunodeficiency virus (HIV) preparation was obtained through BMM it showed no infectivity. Electron microscopic observation revealed that HIV was completely caught by the multilayers of the BMM. Conveniently, BMM was seldomly found to adsorb protein molecules and also to have a high filtration rate. These characteristics may have a use in the removal of other variously sized pathogenic agents from plasma.     

Transcatheter arterial embolization of hemangiomas in the perioral region

This paper presents four cases with successful transcatheter arterial embolization (TAE) for oral and perioral hemangiomas. Four TAEs were performed without major complications and the tumors disappeared in one case and decreased in size in the other 3 cases.     

9-cis retinoic acid enhances the antiviral effect of interferon on hepatitis C virus replication through increased expression of type I interferon receptor

The concentration of type I interferon receptor (IFN-Rc) in the liver is a crucial factor in determining the efficacy of interferon (IFN) therapy in patients with chronic hepatitis C. Retinoic acids (RAs) can enhance the expression of type I IFN-Rc expression. The aim of this study was to investigate whether RAs increase the anti-hepatitis C virus (HCV) effect of IFN through an increase in IFN-Rc. The hepatocellular carcinoma cell line HuH-7 was treated with 10(-7) mol/L all-trans RA (ATRA) and 9-cis RA (9-CRA). Expression of type I IFN-Rc was investigated at both the mRNA and protein levels with the use of real-time quantitative polymerase chain reaction and flow cytometry, respectively. We investigated the anti-HCV effect, using in vitro HCV transfection, by monitoring the level of HCV RNA in the culture medium. ATRA and 9-CRA enhanced the expression of type I IFN-Rc at both the mRNA and protein levels. After IFN-alpha treatment, the activity of 2,5'-oligoadenylate synthetase was enhanced by RAs, and this enhancement was abolished when blocking antibodies had previously been bound to the surface receptors. IFN treatment decreased the concentration of HCV RNA, and this effect was enhanced by treatment with RAs. Our findings suggest that RAs enhance the anti-HCV replication effect of IFN-alpha through up-regulation of type I IFN-Rc in HuH-7 cells.     

Quantitative evaluation of the therapeutic effects of antibiotics using silkworms infected with human pathogenic microorganisms

The injection of bacteria (Staphylococcus aureus, Stenotrophomonas maltophilia) or true fungi (Candida albicans, Candida tropicalis) that are pathogenic to humans into the silkworm hemolymph leads to death of the larvae within 2 days. Antibiotics used for clinical purposes have therapeutic effects on silkworms infected with these pathogens. The 50% effective doses obtained by injection into the silkworm hemolymph are consistent with those reported for mice. Injection of vancomycin and kanamycin into the silkworm hemolymph was effective, but oral administration was not. Chloramphenicol, which is effective by oral administration, appeared in the silkworm hemolymph soon after injection into the midgut, whereas vancomycin did not. Isolated midgut membranes were impermeable to vancomycin. Thus, the ineffectiveness of oral administration of vancomycin to silkworms is due to a lack of intestinal absorption.