Activation of trans-l,2-dihydro-l,2-dihydroxy-6-aminochrysene to genotoxic metabolites by rat and human cytochromes P450

In order to address the hypothesis that 6-aminochrysene (6-AC)is converted to genotoxic products by cytochrome P450 enzymesvia two activation pathways (N-hydroxylation and epoxidation),the activation of 6-AC and trans-l,2-dihydro-l,2-dihydroxy-6-aminochrysene(6-AC-diol) to genotoxic metabolites was examined in rat andhuman liver microsomal cytochrome P450 enzymes using Salmonellatyphimurium TA1535/pSK1002 and TA1535/pSK1002/pNM12 (NM2009)as tester strains. The latter bacteria, an O-acetyl-transferase-overexpressingstrain, was highly sensitive to metabolites derived from activationof 6-AC, but not those from 6-AC-diol, using liver microsomesfrom phenobarbital-treated rats or a reconstituted monooxygenasesystem containing P4502B1 or -2B2, thus suggesting the rolesof P450 and acetyltransferase systems in the activation process.6-AC-diol, on the other hand, was activated very efficientlyby liver microsomes prepared from ß-naphthoflavone-treatedrats or a reconstituted system containing P4501A1 or -1A2; theactivation reaction is considered to proceed through diol-epoxideformation. The contribution of rat P4501A enzymes towards activationof 6-AC-diol was confirmed by the inhibitory effects on theactivation process of -naphthoflavone, a specific inhibitorof P4501 A-related activities, and antibodies raised againstpurified P4501A1 and -1A2. In humans, P4501A2 was found to bethe major enzyme involved in the activation of 6-AC-diol togenotoxic metabolites while the parent compound 6-AC was activatedmainly by P4503A4. Experiments using recombinant P450 proteinsexpressed in human lymphoblastoid cells lines showed that humanP4501A1 could also activate 6-AC-diol to reactive metabolitesat almost the same rate measured with P4501A2. In addition,P4502B6 was found to efficiently catalyze the activation of6-AC to genotoxic metabolites, and P4503A4 was active in theactivation of 6-AC-diol as well as 6-AC. Addition of purifiedrat epoxide hydrolase to the incubation mixture containing purifiedrat P4501A1 or microsomes expressing human P4501A1 caused inhibitionof activation of 6-AC-diol. These results suggest the existenceof different enzymatic activation pathways for 6-AC and 6-AC-diol.The former carcinogen may be N-hydroxylated principally by P4502Benzymes in rats and P4503A4 and -2B6 in humans and activationto its ultimate metabolites may proceed through esterificationof the N-hydroxy metabolites by an N-acetyltransferase. The6-AC-diol is metabolized to its ultimate diolepoxide productby P4501A enzymes in rat and human liver microsomes. P4503A4(humans) and P4503A2 (rats) may also contribute to some extentin the activation of 6-AC-diol, albeit at lower rates than thoseof P4501A enzymes.     

Results of early surgical evacuation of packed intraventricular hemorrhage from aneurysm rupture in patients with poor-grade subarachnoid hemorrhage.

OBJECT: The goal of this study was to evaluate the results of early surgical evacuation of "packed" intraventricular hemorrhage (IVH) in patients with poor-grade subarachnoid hemorrhage (SAH). METHODS: The authors performed surgery within 24 hours after onset of SAH, identified on neuroimaging as a cast distending the ventricular system, in 74 patients with poor-grade SAH (World Federation of Neurosurgical Societies Grades IV and V) without intracerebral hemorrhage. Eighteen of these patients had packed IVH; in these patients the intraventricular clots were extensively evacuated via frontal corticotomy performed under microscopic view. CONCLUSIONS: Overall, 42% of the 74 patients undergoing craniotomy in the acute stage had favorable outcomes, whereas 30% died. Using multivariate analysis, variables significantly associated with favorable outcome in patients with poor-grade SAH included absence of a packed intraventricular clot on computerized tomography scanning; absence of a history of cardiac disease; and a Glasgow Coma Scale score of 11 or 12. None of the 18 patients who had packed IVH had favorable outcomes and seven of these died. In six recently treated patients with packed IVH, which was examined using fluid-attenuated inversion recovery imaging, extensive periventricular brain damage was found both immediately after surgery and during the chronic stage. Accordingly, the authors believe that irreversible periventricular brain damage is already complete immediately after packed IVH occurs.     

Histological factors of 1-h biopsy influencing the delayed renal function and outcome in cadaveric renal allografts

The morphological characteristics of a kidney biopsy specimen taken 1 h after reperfusion of blood into the graft (1-h biopsy) during a cadaveric transplant operation were studied. The aim of the 1-h biopsy is to evaluate the pre-transplant risk factors for the delayed graft function, assess the renal function of the graft, and predict long-term graft survival. The total number of 1-h biopsies was 113, consisting of 86 male and 27 female donors. The mean age of the donors is 39.5 +/- 17.3 yr. Arteriosclerosis (AS) and tubulo-interstitial injury (TI) were both estimated using a semi-quantitative scale. AS score was graded into four categories, according to the severity of the thickening of interlobular artery: 0: none, 1: mild, 2: moderate and 3: severe. No biopsy revealed severe AS of grade 3. The TI score was graded from 0 to 5, according to the morphological injury: 0: none, 1-2 non-specific tubulo-interstitial injury (NSTI), and 3-5 compatible with acute tubular necrosis (ATN) in terms of pathological diagnosis. The mean ages of donors showing as AS of score 0, 1, and 2 were 30.6 +/- 14.6, 49.7 +/- 13.5, and 56.9 +/- 6.30, respectively. The mean donor age of the AS 1 group and AS 2 group was significantly lower than for the AS 0 group. The lowest serum creatinine values after operation (best Cr) of recipients with AS scores of 0, 1, and 2 were 1.31 +/- 0.45, 1.60 +/- 0.70, and 1.84 +/- 0.71 mg/dL, respectively; the best Cr of AS scores of 1 and 2 was significantly higher than in the AS score 0 group. The mean creatinine level at the final point of the AS 0 group was significantly lower than in the combined AS 1 and AS 2 group (serum creatinine 1.44 +/- 1.03 vs 1.87 +/- 1.53 mg/dL: p < 0.01). The duration of severe hypotension less than 50 mmHg or 80 mmHg was significantly shorter in the NSTI group than in the ATN group (less than 50 mmHg was 29.7 +/- 124 vs 72.5 +/- 174, less than 80 mmHg 105 +/- 234 vs 193 +/- 261 min: p < 0.01). The post-operative (po) day expressing diuresis in excess of 1000 mL of urine per d was 8.28 +/- 17.5 and 13.7 +/- 23.3 (p < 0.01) in the NSTI and ATN group, respectively. The po-d of the last hemodialysis and the po-d showing serum creatinine less than 2.0 mg/dL in NSTI and ATN group was 7.74 +/- 17.4 and 13.3 +/- 23.2 (p < 0.01), and 25.0 +/- 30.5 and 38.0 +/- 35.2 (p < 0.01), respectively. We concluded that 1-h renal biopsy is useful for assessing the outcome of renal allograft. AS of a donor kidney is one of the most important risk factors for both short and long-term outcome of the graft. The TI score was useful to predict the outcome of delayed graft function.     

Influence of antigenic forms and adjuvants on the IgG subclass antibody response to Aujeszky's disease virus in mice.

The influence of antigenic forms of Aujeszky's disease virus (ADV) and adjuvant types on the production of IgG subclass antibodies in mice was investigated. Particulate antigen, inactivated ADV, alone induced IgG1 and lower IgG2a antibody production, while the antigen adsorbed onto aluminum phosphate gel (alum) enhanced IgG1 antibody production but suppressed IgG2a antibody production as well as solubilized ADV antigen adsorbed onto alum. QS21 saponin purified from Quillaja saponaria promoted the production of IgG1 and IgG2a antibodies in a large extent against the both particulate and soluble antigens, while this saponin has strong hemolytic activity. Lablaboside F saponin isolated from Dolichos lablab without hemolytic activity, also induced the production of large IgG1 and little IgG2a antibody against both antigens. Oil-based adjuvant, ISA70 of water-in-oil type and ISA25 of oil-in-water type, increased IgG1 and IgG2a antibodies against the both soluble and particulate antigens, whereas a combination of ISA25 and soluble antigen reduced IgG2a antibody response. These results indicate that IgG1 antibody production was not suppressed by a combination of antigenic form and adjuvant type, however, IgG2a antibody production was influenced.     

Evaluation of child-rearing environmental factors that affect the occurrence of sudden infant death syndrome: interview conducted by public health nurses]

PURPOSE: We examined the child-rearing environmental factors that affect the occurrence of sudden infant death syndrome (SIDS) by using a nation-wide survey. METHOD: Infants who died due to SIDS between January 1996 and June 1997 in Japan were identified from death certificates. Controls of the same sex, birthplace, and birth months as the corresponding SIDS were chosen from birth certificates. Interviews of both cases and controls were undergone in January and February 1998 by public health nurses. RESULTS: The following Child-rearing factors exhibited a significant relationship with the occurrence of SIDS: 1. Concerning the sleeping position, the prone position was associated with increased risk compared to the supine position, with an odds ratio of 3.02 (95% c.i. 2.07-4.65). 2. Regarding the feeding method, artificial feeding only demonstrated a higher risk than breast feeding only, with an odds ratio of 4.92 (95% c.i. 2.78-9.63). 3. With regard to smoking, infants with both parents who smoked exhibited a higher risk than infants where neither parents smoked, with an odds ratio of 3.50 (95% c.i. 1.74-8.32).     

Effectiveness of portable toothbrush use on reducing cigarette consumption and improving oral health

There have been many studies on the influence of smoking on health, and in recent years, there have also been studies examining the relationship between smoking and oral health, concluding that smoking has a considerable detrimental effect on oral health. We introduced in a number of companies the idea of "Non smoking through the use of a portable toothbrush" as a means of giving up smoking while at the same time promoting oral health. The results demonstrated that consumption of cigarettes was reduced in about 50 percent of cases, while some improvement in mouth freshness was seen in about 90 percent. The study also showed that the success rate in reducing cigarette consumption through the use of a portable toothbrush was higher in highly motivated subjects, leading us to conclude that motivation is a major factor in reducing cigarette consumption. The study impressed on us the importance of educating people on the effect of smoking on oral health and the possibility of using a portable toothbrush as a means of reducing smoking.     

Effects of high temperature on the emergence and survival of adult Culex pipiens molestus and Culex quinquefasciatus in Japan.

The emergence rate and adult survival (longevity) of Japanese strains of Culex pipiens molestus and Culex quinquefasciatus were compared at temperatures of 21, 25, and 30 degrees C. The pupation and emergence rates in both strains were higher at 21 and 25 degrees C than at 30 degrees C. The adult emergence rate, especially in females, was lower in Cx. p. molestus than in Cx. quinquefasciatus. Longevity of females and males was lower in Cx. p. molestus at 25 degrees C and above. The survival of Cx. p. molestus was adversely affected by temperatures of 28 degrees C and higher. High temperature may restrict the distribution of this species. Therefore, if Cx. p. molestus infests the Okinawa region, the likelihood that it will become established is minimal.     

The effect of mitomycin C after long-term storage on human Tenon's fibroblast proliferation.

PURPOSE: To investigate the effect of mitomycin C (MMC) after long-term storage on proliferation of human Tenon's fibroblasts in vitro. METHODS: Human Tenon's fibroblasts in tissue culture were exposed for 5 minutes to MMC (0.4 mg/mL) that was either freshly prepared or had been stored for as long as 18 months at either 4 degrees C or -20 degrees C. The MTT colorimetric assay was used to determine the inhibition of proliferation as measured indirectly by mitochondrial activity. RESULTS: The inhibition rate was 88% using fresh MMC, and declined to a mean of 73% when using MMC that had been stored for as long as 18 months at 4 degrees C; this decrease was not statistically significant. The mean inhibition for MMC stored at -20 degrees C was 68%, and this was significantly less than inhibition with fresh MMC. Inhibition did not vary significantly with MMC after different storage times. CONCLUSION: Mitomycin C continues to have strong in vitro antiproliferative effects when stored for as long as 18 months at 4 degrees C or -20 degrees C. A significant decline in potency compared with fresh MMC occurs when MMC is stored at -20 degrees C.     

Oral administration of sepimostat mesilate prevents acute alcohol pancreatic injury in rats.

The preventive effect of a novel synthetic serine protease inhibitor, sepimostat mesilate (sepimostat), on acute alcohol pancreatic injury, induced by exocrine hyperstimulation and ethanol administration, was assessed and compared with that of a similar protease inhibitor, camostat mesilate (camostat). Conscious rats were infused with 1 microg mL(-1) h(-1) caerulein intravenously for 6 h and with 0.1 g mL(-1) h(-1) ethanol for 9 h, with the latter infusion beginning 3 h after the start of the caerulein infusion. Sepimostat or camostat was administered orally 1 h before the caerulein infusion. Rats infused with caerulein plus ethanol showed increased plasma amylase and lipase activities, and aggravated pancreatic interstitial oedema when compared with rats given caerulein alone. Sepimostat at 10 and 30 mg kg(-1) prevented the increase in plasma amylase and lipase activities caused by caerulein plus ethanol infusion. Sepimostat at 30 mg kg(-1) suppressed the histological change. Camostat did not show any preventive effects at the equivalent dose. When conscious rats were infused with 1 microg mL(-1) h(-1) caerulein alone intravenously for 6 h, plasma amylase and lipase activities were increased compared with rats given saline. Neither drug prevented the increase in these activities at 30mg kg(-1). Our results suggest that sepimostat has superior preventive effects on alcohol-induced acute pancreatic injury compared with camostat. Sepimostat may thus be a useful drug in the therapy of alcohol-induced pancreatitis.     

Pharmacological studies of Reiousan, a drug containing bezoar and ginseng--effects on the blood rheology]

Effects of Reiousan, a crude drug preparation consisting of bezoar and ginseng, on blood rheology were studied. Reiousan improved the deformability of rat erythrocytes exposed to hyperosmorality and treated with phenylhydrazine. The ATP depletion in erythrocytes, the polybrene-induced erythrocyte aggregation and the oxidation of low density lipoprotein were suppressed by Reiousan. Oral administration of Reiousan also improved the erythrocyte deformability in phenylhydrazine-treated rats and delayed the thromboembolic death induced by arachidonic acid in mice. These results suggest that Reiousan has an ameliorative effect on blood rheology related to "Oketsu" syndrome in Kampo diagnostics.