Activation of protein kinase C and nicotinamide adenine dinucleotide phosphate oxidase in leukocytes of spontaneously hypertensive rats.

The involvement of oxidative stress in polymorphonuclear leukocytes (PMN) in the pathogenesis of hypertension remains to be elucidated. We analyzed the generation of reactive oxygen species (ROS) by the circulating and peritoneally infiltrating PMN from spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). Flow cytometric analysis revealed that ROS generation by PMN from SHR was higher than that from WKY before (at 6 weeks of age) and after (at 16 weeks of age) the onset of hypertension. In vivo, ROS generation by PMN from SHR, but not that by PMN from WKY, was significantly suppressed by 10-week treatment with 50 mg/kg/day carvedilol, and this treatment did not affect blood pressure. Western blotting analysis revealed that protein kinase C alpha (PKCalpha), but not PKCbetaI or betaII, was activated more strongly in PMN from SHR than in PMN from WKY. Furthermore, expression of p47phox of nicotinamide adenine dinucleotide phosphate oxidase, but not of p67phox, in PMN from SHR was higher than that in PMN from WKY. These results suggest that ROS generation by PMN is principally enhanced in SHR through activation of PKCalpha and p47phox.     

Determination of ion recombination loss by two-voltage method for pulsed radiation beams.

The ion recombination loss is one of the most important correction factors for dosimetry using ionization chamber especially for the measurement of high-intensity pulsed radiation beam. The two-voltage method has been used frequently for the correction of ion recombination loss. Several ways to approximate the method are presented. Comparisons were carried out to check the validity of the approximation. Using four ionization chambers of different types and shapes, measurements were made to obtain the optimal value of the ratio for the two voltages.     

Effects of AETT-Induced Neuronal Ceroid Lipofuscinosis on Learning Ability in Rats

Abstract: The behavioral effects of ceroid-lipofuscin accumulation, induced by intraperitoneal administration of acetyl-ethyl-tetramethyl-tetralin (AETT) in Wistar rats for 3 months, were examined in the present studies. A significant increase in neuronal ceroid-lipofuscin was demonstrated neuropathologically as well as morphometrically. Although the AETT-intoxicated rats showed neither alteration of locomotor activity nor shock sensitivity, a significant impairment of learning ability, especially an acquisition trial in passive avoidance tests, was observed. Results of the present studies indicate the possibility that a diffuse lipofuscin accumulation causes a learning impairment in rats. The results also imply the possibility of a significant role of age-related lipofuscin accumulation in the dementing processes of human especially in the elderly.     

Hemorrhagic cystitis after bone marrow transplantation: importance of a thin sectioning technique on urinary sediments for diagnosis.

We used a thin-sectioning technique for the electron microscopic detection of viral particles within the cells of urinary sediments in three recipients who developed hemorrhagic cystitis after allogeneic bone marrow transplantation. Results of viral cultures of urine and electron microscopic (EM) observations on urinary sediments were consistent in only one recipient. In this recipient, EM observations revealed many viral particles within the cells of urinary sediments with diameter of about 80 nm corresponding to adenovirus, of which type 11 was produced in viral cultures. In one of the other two recipients many viral particles with a mean diameter of 41.6 nm corresponding to papovavirus were observed, but viral cultures using conventional cells were negative. Re-cultures using HEK cells produced polyomavirus BK. EM observation was a clue to the correct diagnosis. In the remaining recipient, no viral particles were observed within the cells of urinary sediments, suggesting the hemorrhagic cystitis to be of non-viral origin, despite a positive result of viral culture. These results suggest that a thin-sectioning technique on the cells of urinary sediments is important for the differential diagnosis between a viral-induced and non-viral hemorrhagic cystitis.     

Epidemiological characteristics of acute pulmonary thromboembolism in Japan.

AIM: In Japan, acute pulmonary thromboembolism (APTE) is still rare, but the number of patients with APTE has been steadily increasing. It is important for early diagnosis and early management of APTE to recognize epidemiological characteristics of this condition. METHODS: We investigated the epidemiological characteristics of 252 patients with APTE who were admitted to our institutions between 1975 and 2001. APTE was more prevalent in women that in men. It was observed the most in the age group between 50s to 70s, especially in women. Many patients had prolonged immobilization, recent major operation, obesity, or cancer, as risk factors for venous thromboembolism. One hundred and thirty-eight patients developed APTE in hospital; 60 patients were in Department of Internal Medicine, 28 in General Surgery, 15 in Orthopedics, 15 in Obstetrics and Gynecology, and 20 in other services. RESULTS: Among 58 patients with malignancy, 43% had cancers in digestive organs, 21% in gynecological, and 17% in urological. Among 61 patients who were examined for the presence of thrombophilia, 13 patients had inherited thrombophilia (8 protein C deficiency, 4 protein S deficiency, and 1 antithrombin III deficiency) 11 had antiphospholipid antibodies which indicated thrombophilia. Five out of the above 61 patients (8%) had no obvious risk factors including thrombophilia. CONCLUSION: The findings in our patients were almost the same as those in Western patients, except for some points. These results might be useful to establish a preventive approach for APTE in Japan.     

Effects of arginine derivatives on soluble guanylate cyclase from neuroblastoma N1E 115 cells

The effects of L-arginine (Arg) derivatives on soluble guanylate cyclase from neuroblastoma N1E 115 cells were examined. The Arg derivatives were modified at the -NH2, -COOH, C alpha-proton or guanidino group of Arg. Among the synthesized derivatives, eight compounds, i.e. the 5-(dimethylamino)-1-naphthalenesulfonyl (DNS) ones, especially N-cyclohexyl-2-(N-DNSamino)-5-guanidino-2-methylvaleramide and 1-[2-(N-DNSamino)-2-(2-imino-1,2,3,4,5,6-hexahydropyrimidin- 4-yl)acetyl]- piperidine, were found to inhibit the activity of crude guanylate cyclase in the 105,000 g supernatant fraction of the cell homogenate. The enzyme, partially purified by a column of Chelex 100 Na+, was also inhibited by these eight compounds. The mode of the inhibition was competitive. The Ki values were in the range of 2-8 microM for the enzyme in the 105,000 g supernatant fraction and 3-16 microM for the partially purified enzyme, in the presence of Mg2+ as a metal cofactor. In contrast, a new derivative, methyl 2-amino-5-guanidinovalerate (M Arg ME), as well as the Arg methyl ester (Arg ME) and Arg; were found to enhance the activity of the partially purified guanylate cyclase; KA values of M Arg ME, Arg ME and Arg were approximately 9, 4 and 3 microM respectively. From these results, the free guanidino group including 2-imino-1,2,3,4,5,6-hexahydropyrimidin-4-yl or 2-imino-1,2,3,4,5,6-hexahydropyrimidin-5-yl and modification of the --NH2 residue with a hydrophobic group such as DNS seemed to be essential for inhibition of the guanylate cyclase; however, the guanidino and --NH2 residue of Arg should be free for activation by these Arg derivatives.     

‘Ischemic tolerance’ phenomenon detected in various brain regions

We investigated the effects of mild and non-lethal ischemic insult on neuronal death following subsequent lethal ischemic stress in various brain regions, using a gerbil model of bilateral cerebral ischemia. Single 10-min ischemia consistently caused neuronal damage in the hippocampal CA1, CA2, CA3 and CA4, layer III/IV of the cerebral cortex, dorsolateral part of the caudoputamen and ventrolateral part of the thalamus. On the other hand, in double ischemia groups, 2-min ischemic insult 2 days before 10-min ischemia exhibited significant protection in the CA1 and CA3 of the hippocampus, the cerebral cortex, the caudoputamen and the thalamus. Five-min ischemic insult 2 days before 10-min ischemia also showed protective effect in the same areas as those of 2-min ischemia except for the CA1 region of the hippocampus, while 1-min ischemic insult exhibited no protective effect in any brain regions. In the immunoblot analysis, both 2- and 5-min ischemia caused increased synthesis of heat shock protein 72 (HSP 72) in the hippocampus, but 1-min ischemia did not. The present study demonstrated that the ‘ischemic tolerance’ phenomenon was widely found in the brain and also suggested that ischemic treatment severe enough to cause HSP 72 synthesis might be needed for induction of ‘ischemic tolerance’.