Genotoxicity studies on green tea catechin.

The beneficial effects of tea catechins are well documented. We evaluated the genotoxic potential of a green tea catechin preparation using established genotoxicity assays, including a bacterial reverse mutation assay (Ames test), a chromosomal aberration assay in cultured Chinese hamster lung cells (CHL/IU), a mouse lymphoma L5178Y/tk assay, and a bone marrow micronucleus (MN) assay in ICR CD mice and SD rats. No significant increases in the number of revertant colonies were observed in the Ames test, but positive responses were observed in two in vitro assays: the chromosomal aberration assay and mouse lymphoma L5178/tk assay. However, the in vivo study demonstrated no significant increase in micronucleated polychromatic erythrocytes (MNPCE) in the bone marrow of both ICR CD mice and SD rats administered a high dose of the green tea catechin preparation up to 2000mg/kg. Combined with favorable epidemiological information suggesting a chemopreventive effect of tea catechins on carcinogenesis, we conclude that green tea catechin presents no significant genotoxic concern under the anticipated conditions of use. These results are consistent with other genotoxicity studies of tea catechins, which show minimal, if any, genotoxic potential.

Genotoxicity studies on dietary diacylglycerol (DAG) oil.

Dietary diacylglycerol (DAG) oil is an edible oil enriched in DAG (more than 80%). A recent investigation indicated that DAG oil or its components may have beneficial effects on the prevention and management of obesity. We evaluated the genotoxic potential of DAG oil using standard genotoxicity tests. Bacterial reverse mutation assay (Ames test), the chromosomal aberration assay in cultured Chinese hamster lung cells (CHL/IU), and a bone marrow micronucleus assay in ICR CD mice were employed in the present study. In addition we have tested the possibility that genotoxic substances may be formed during cooking, heated DAG oil (HDG) was prepared by batch frying potato slices in the oil at 180 degrees C for 8 h/day for three consecutive days. Therefore, genotoxicity tests were also performed on HDG. Results obtained did not show any genotoxic effect on either unheated DAG oil (UDG) or HDG. We conclude that there are no safety concerns on the genotoxicity of DAG oil under the conditions for normal use.

Increase in serum 1,25-dihydroxyvitamin D and hypercalcaemia in a patient with inflammatory myofibroblastic tumour.

Hypercalcaemia complicates the clinical course of a substantial number of patients with advanced cancer. This report describes a patient with an inflammatory myofibroblastic tumour in soft tissue who developed an inflammatory reaction, hypercalcaemia, and a high serum concentration of 1,25 dihydroxyvitamin D. Serum concentrations of 25-hydroxyvitamin D, parathyroid hormone, and parathyroid hormone related protein were normal. Histological examination of the tumour revealed fibrosarcoma with abundant macrophage infiltration. mRNA for 25-hydroxyvitamin D-1alpha-hydroxylase was identified in the tumoral tissue. In view of this case, inflammatory myofibroblastic tumour should be added to the list of diseases that are responsible for vitamin D mediated hypercalcaemia.

Seasonal blood pressure and body weight variation in patients on chronic hemodialysis.

AIM: The relation of ambient temperature (AMT) and relative humidity to systolic blood pressure (SBP), diastolic blood pressure (DBP), body weight (BW), and body weight gain between dialysis sessions (DeltaBW) was examined in hemodialysis patients by Fourier analysis. METHODS AND RESULTS: The authors recruited 144 dialysis patients from a hemodialysis center in Okinawa, Japan where there is distinct seasonal variation in monthly AMT but a constant intradiurnal temperature change throughout the year. All patients had been undergoing chronic and regular hemodialysis three times per week. SBP, DBP, and BW before dialysis sessions and DeltaBW were recorded in 1994. Mean monthly Okinawa AMT in 1994 was highest in August and lowest in February and March, and the mean monthly relative humidity in 1994 was highest in June and lowest in January. Mean SBP and DBP were lowest in August and June respectively, and greatest in December. BW was lowest in July and September, and greatest in February and March; DeltaBW was lowest in July and greatest in January. These seasonal patterns were well reproduced by the first Fourier component. The cross-correlation coefficient showed that monthly mean AMT and SBP, DBP, BW, and DeltaBW were correlated with a lag time of 5 or 6 months. The cross correlation coefficient showed that relative humidity and SBP, DBP and DeltaBW were also correlated with a 6-month lag time. In analyzing subgroups of patients according to the presence or absence of antihypertensive medications, a seasonal change was observed in the SBP and DBP of patients not being treated with antihypertensives, and in the DBP of patients taking antihypertensive medications, but not in the SBP of patients taking antihypertensive medications. CONCLUSION: Seasonal variations in SBP, DBP, BW and DeltaBW were evident. AMT and the relative humidity correlated strongly with SBP, DBP, BW and DeltaBW. The clinical implications of these findings in hemodialysis patients warrant further investigation.

Inactivation of human viruses by povidone-iodine in comparison with other antiseptics.

Inactivation of a range of viruses, such as adeno-, mumps, rota-, polio- (types 1 and 3), coxsackie-, rhino-, herpes simplex, rubella, measles, influenza and human immunodeficiency viruses, by povidone-iodine (PVP-I) and other commercially available antiseptics in Japan was studied in accordance with the standardized protocol in vitro. In these experiments, antiseptics such as PVP-I solution, PVP-I gargle, PVP-I cream, chlorhexidine gluconate, alkyldiaminoethyl-glycine hydrochloride, benzalkonium chloride (BAC) and benzethonium chloride (BEC) were used. PVP-I was effective against all the virus species tested. PVP-I drug products, which were examined in these experiments, inactivated all the viruses within a short period of time. Rubella, measles, mumps viruses and HIV were sensitive to all of the antiseptics, and rotavirus was inactivated by BAC and BEC, while adeno-, polio- and rhinoviruses did not respond to the other antiseptics. PVP-I had a wider virucidal spectrum, covering both enveloped and nonenveloped viruses, than the other commercially available antiseptics.

Seasonal variation in the incidence of end-stage renal disease.

The effect of ambient temperature (AMT) on the incidence of end-stage renal disease (ESRD) was examined in Okinawa, Japan, where there is a distinct seasonal variation in monthly AMT but constant intradiurnal temperature change throughout a year. Arbitral continuous and cyclic functions were examined using Fourier analysis and calculation of the cross-correlation coefficient. The calendar month of the start of chronic dialysis was regarded as the time of onset of ESRD. A total of 1,982 patients, 824 females and 1,158 males, was registered with ESRD between 1971 and 1990. The normalized monthly number of new ESRD patients, divided by days of each month, was smallest in August, n = 4.06, and largest in January, n = 6.45, and this pattern was well reproduced by the Fourier synthesized value. The cross-correlation coefficient showed that monthly mean AMT and the normalized number of ESRD patients correlated best with 6 months lag time. Taken together, our results showed that there was strong correlation between the normalized number of ESRD patients and AMT. Uremic symptoms leading to initiate dialysis, such as congestive heart failure, may be aggravated in lower AMT. We speculated a role of an inverse relation between AMT and the sympathetic nerve function. The public health implications of these findings warrant their further investigation.

Pharmacological characterization of the nonpeptide angiotensin II receptor antagonist, U-97018.

We examined the pharmacological properties of U-97018, a novel nonpeptide angiotensin II (AII) receptor antagonist, in various in vitro and in vivo studies. U-97018 selectively displaced 125I-AII specific binding in the membrane fraction derived from the rat mesenteric artery and adrenal cortex (AT1 subtype) with IC50 of 1.3 +/- 0.2 and 7.7 +/- 1.3 nM, respectively, without altering the AII binding of the rat adrenal medulla (AT2 subtype). In rat adrenal cortical cells, U-97018 inhibited 1 nM AII-induced aldosterone secretion with an IC50 of 0.48 nM; it shifted concentration-secretion response curve for AII to the right and inhibited the maximal response to AII, yielding a pKB of 9.8. Similarly, U-97018 showed insurmountable antagonism with a pKB of 10.6 against the AII-induced contraction in the isolated rabbit aorta. U-97018 had no direct effect on the activities of renin and angiotensin converting enzyme in vitro. In pithed rats, U-97018 inhibited the AII-induced pressor response with an ED50 of 0.28 mg/kg, i.v. without any partial agonistic activity. In anesthetized rats and dogs, intraduodenal administration of U-97018 at a dose of 1 mg/kg inhibited the AII-induced pressor response by about 60%. In spontaneously hypertensive rats, U-97018 at 10 mg/kg p.o. produced antihypertensive effects which lasted for 24 hr after administration. Thus, U-97018 is an orally active, insurmountable AII receptor antagonist without any agonistic activity.

A sialidase activity in the midgut of the insect Triatoma infestans is responsible for the low levels of sialic acid in Trypanosoma cruzi growing in the insect vector.

Trypanosoma cruzi expresses a unique trans-sialidase that is responsible for the transfer of sialic acid from host glycoproteins and glycolipids to mucin-like glycoprotein acceptors on the parasite surface. The enzyme and the sialic acid acceptors are present in the mammalian forms of the parasite and in the parasite forms that grow in axenic cultures, which correspond to the developmental stages found in the insect vectors. Here we show that parasite forms growing in the vector Triatoma infestans express trans-sialidase in the hindgut portions of the insect. However, the sialic acid acceptors are poorly sialylated due to the low concentration of sialic acid donors in the gut lumen of T.infestans, which feeds exclusively on blood that is rich in sialic acid donors. These low levels of sialic acid donors are due to a novel sialidase activity present mainly in the anterior midgut with high specificity for alpha-2,3-sialyllactose, but not for alpha-2,6-sialyllactose. The activity is present in starved insects or insects fed with culture medium, indicating that it did not originate from the blood meal. Enzyme activity does not decrease in insects fed with antibiotics, is present in the salivary glands, and the few bacteria isolated from the gut and faeces of T.infestans did not display sialidase activity, indicating that the enzyme is not derived from a commensal organism. This novel activity could have a nutritional role in the gut of haematophagous insects and indicates that acquisition of sialic acid is not required for parasite development in the gut of T.infestans.

Effects of U-97018 on pressor responses to intracerebroventricularly administered angiotensin II in conscious normotensive rats.

We examined the effects of U-97018, an AT1 receptor antagonist, on the pressor response to intracerebroventricularly (i.c.v.) administered angiotensin II (AII) in conscious normotensive rats in comparison to losartan, EXP 3174, EXP 655, and saralasin. In an i.c.v. study, U-97018, losartan, and EXP 3174 reduced the pressor response. EXP 655, an AT2 selective antagonist, also inhibited the pressor response to i.c.v. AII. U-97018 combined with EXP 655 did not fully eliminate the pressor response to i.c.v. AII. Moreover, saralasin, a nonselective peptide AII antagonist, also failed to abolish the pressor response to i.c.v. AII. Therefore, both AT1- and AT2-receptors probably are functional in inhibiting the pressor response to i.c.v. AII and that a part of the i.c.v. AII-induced pressor response occurs through non-AT1- and non-AT2-receptors. In an intravenous (i.v.) study, U-97018, losartan, and EXP 3174 reduced the pressor response to i.c.v. AII. At 10 mg/kg orally (p.o.), which is an antihypertensive dose in spontaneously hypertensive rats (SHR), neither U-97018 nor losartan reduced the pressor response to i.c.v. AII even at 180 min after administration. This result indicates that neither U-97018 nor losartan, at the oral antihypertensive dose, reaches the brain in sufficient amount to affect the pressor response to i.c.v. AII.

Small, round-structured viruses (SRSVs) associated with acute gastroenteritis outbreaks in Gifu, Japan.

Two outbreaks of non-bacterial gastroenteritis occurred in Gifu prefecture in January 1989 and in January 1991. Both outbreaks were closely related to the consumption of raw oysters, and showed similar clinical features. Small, round-structured virus particles were found in patient stools in both outbreaks by electron microscopy. The role of these particles as the causative agents of the outbreaks were strongly suggested by immune electron microscopy and/or western-blotting immunoassay. When compared with SRSV-9 (Tokyo/SRSV/86-510) reported previously (Hayashi et al, J. Clin. Microbiol., 27: 1728-1733, 1989), it was found that these viral particles were antigenically similar to SRSV-9, and had a major structural protein of 63 kilodaltons (kDa). Further, the prevalence of this agent in Gifu area was examined by western blot antibody assay using 67 serum samples collected from the inhabitants in 1991. The results indicated the circulation of the same or antigenically similar agent in this area.

Ecological studies on reovirus pollution of rivers in Toyama Prefecture. II. Molecular epidemiological study of reoviruses isolated from river water.

In order to clarify the source of reovirus pollution in river water, comparative surveys have been carried out between reovirus isolates from river water and those from sewage, human or animal, by making use of the analysis of genomic RNA-migration pattern of reovirus in polyacrylamide gel electrophoresis (electropherotype). The strains of reovirus serotype 1 and 2 isolated from river water were classified into 3 and 9 electropherotypes, respectively, and 8 out of these 12 types were also found among strains isolated from sewage or human. When the monthly distribution of the river isolates classified by electropherotypes was compared with that of the sewage isolates, there were cases in which strains of the same electropherotype were simultaneously isolated from both sources. The electropherotypes of 3 isolates from pig and field rodents were different from those of the other isolates. The electropherotype of an oyster isolate coincided with that of some of the isolates from humans and river water. These results indicate that the major source of reoviruses polluting river water may be the human excretion.

Separation of closely related large peptides by micellar electrokinetic chromatography with organic modifiers.

Large peptides with similar electrophoretic mobilities were separated by micellar electrokinetic chromatography (MEKC) with organic modifiers. [Leu13]motilin and [Met13]motilin differ by only one neutral amino acid residue. Because the electrophoretic mobilities of these peptides are almost identical, these peptides were not separated by capillary zone electrophoresis (CZE). Such large peptides have not been separated by conventional MEKC either, because they interacted strongly with the micelle. However, they were completely separated by MEKC when an organic solvent was added to the micellar solution. Some insulins, larger peptides than motilin, from different origins, which have very similar electrophoretic mobilities, were also successfully separated by the same technique. The size of peptides which were separated without organic modifiers was examined.

Seroepidemiology of spotted fever group rickettsiae in small field rodents in Japan.

To clarify the geographic distribution of spotted fever group (SFG) rickettsiae in Japan, small field rodents captured in endemic and nonendemic areas were screened for anti-SFG rickettsia antibodies by the immunofluorescence test. Among total 716 specimens tested, 73-75% of rodents were antibody-positive against Rickettsia japonica and/or Rickettsia montana, showing different degree of antibody-positive proportions among each species of the rodents. Interestingly, these profiles were not different in the rodents from each endemic and nonendemic areas, indicating that the SFG rickettsiae are prevailing in the wider areas where patients have not been found yet.

[Oral health condition of the population in special elderly nursing home].

With the objective of making clear the oral health condition of chronic disable elderlies and thereby obtaining information for oral hygiene education and dental treatment, 77 elderlies in a special elderly nursing home attached to a private general hospital in Niigata Prefecture were studied by an interview/questionnaire method and dental examination. The following results were obtained. (1) Their mean age was 82.0 years. The major causes of chronic disability were diseases of the cerebral blood vessel and these diseases accounted for 54.5% of all diseases. The mean period of their chronic disability was 9 years. (2) 49.4% (38 persons) of them was edentulous, and 47.9% (18 persons) of them was using complete denture. (3) The average number of present teeth was 4.6 in all persons, while it was 9.0 in dentulous persons, and 3.3 of which were residual roots. (4) Salivary occult blood reaction test was positive in 87.2% in the dentulous persons and 34.2% in edentulous persons. (5) Simplified culture test using STOMASTAT was negative in 48.4% and positive in 51.6% of persons using a denture. (6) The above results indicated that dental diseases of chronic disable elderlies are not treated appropriately. This study revealed importance of dental examination, oral hygiene education and initial treatment in middle-aged and older persons.

Comparison of in vivo binding of aromatic nitro and amino compounds to rat hemoglobin.

The hemoglobin (Hb) binding of five nitroarenes, i.e. nitrobenzene (NB), 4-nitrobiphenyl (4-NBP), 1-nitropyrene (1-NP), 2-nitronaphthalene (2-NN) and 2-nitrofluorene (2-NF), and the corresponding amines, administered p.o. to male S.D. rats, was determined by HPLC, to evaluate the extent of in vivo reductive and oxidative activations of these compounds to N-hydroxylamines, which covalently bind to Hb to form acid-labile sulfinamides. Hb binding of the nitroarenes, except for NB, was significantly lower than that of the corresponding amines. Among the aromatic amines, 4-aminobiphenyl exhibited extremely high Hb binding. Hb binding of NB and 4-NBP decreased markedly after pretreatment with a mixture of antibiotics, but the binding of the others did not decrease appreciably. 1-Aminopyrene and 1-NP bound abundantly to plasma proteins, although the Hb binding was slight. Based on the Hb binding and the in vitro metabolism by liver microsomes and intestinal bacteria, the extent of in vivo reductive activation of nitroarenes is discussed.

[Variations of clinical rest position in complete denture-wearing subjects].

With a view to proposing concrete grounds for the measurement of the rest vertical dimension on the face in the establishment of the vertical dimension of occlusion for edentulous patients, 20 complete denture-wearing subjects were made to take a clinical rest position by 4 different denture-wearing patterns, i.e. setting both dentures (UL), setting maxillary denture only (U), setting mandibular denture only (L) and completely edentulously (O), and were measured for the distance between 2 points on the face by slide calipers masking the reading part. The data were statistically analyzed and the following results were obtained. 1) Rest vertical dimension was largest for L, and significant differences were noted between UL, O, U and L, but not between UL and O, between UL and U and between O and U. 2) No significant difference in rest vertical dimension was noted between subjects of not more than 65 years and those of not less than 65 years. 3) No significant difference in rest vertical dimension was noted between the group of subjects of not more than 6 edentulous years and that of subjects of not less than 6 edentulous years. 4) The above results give suggestions to the measurement and evaluation of the vertical dimension between 2 points on the face when jaws are in the vertical relationship with the clinical rest position, in the establishment of the vertical dimension of occlusion.

[Evaluation of epithesis by others].

The present study aims at recognizing how maxillofacial prostheses prepared by us for out patients are evaluated by persons in contact with them. Questionnaire was sent to 158 persons (125 fifth year students of The Nippon Dental University, School of Dentistry at Niigata, 17 dental hygienists and nurses and 12 hospital clerical employees). The following results were obtained: 1) Upon seeing a maxillofacial defective patient momentarily, 91.8% of the answers regarded his inserted maxillofacial prostheses as agreeable. 2) Upon being opposite to such a patient without conversation for a comparatively long time, 18.3 and 80.4% of the answers regarded his covering the defective part with gauze and his inserted maxillofacial prostheses, respectively as agreeable. 3) Upon conversing with such a patient, 86.1 and 9.5% of the answers regarded his inserted maxillofacial prostheses and his covering the defective part with gauze, respectively as agreeable. 4) In the case of close relatives of such a patient, 67.7, 20.3 and 5.7% regarded his inserted maxillofacial prostheses, his covering the defective part with gauze and his leaving the defective part as it is, respectively, as agreeable. 5) With respect to the facial aesthetics of the case presented as one of reference, 42.7, 15.9 and 13.3% pointed out mandibular deviation, ocular prostheses and condition of contact of the maxillofacial prostheses with the skin, respectively, to be unnatural.

[Suitability of denture base by light-cured resin for reline].

With a view to evaluating the dimensional accuracy of the light-cured relining resin from the viewpoint of the suitability of the mucosal surface of the denture base, an experiment by direct relining technique was made using a total of 12 materials, i.e. 2 kinds of denture base material, 3 kinds of relining material and 2 kinds of denture base mold; cured, refined test sample interposed by impression material was adapted to the prototype and was measured for the thickness of impression material by means of stereoscopic microscope. The results obtained were as follows: 1) Lifting discrepancies averaged 0.5, 0.8 and 1.2mm for E (Eporex-E), R (Rebaron) and T (Triad), respectively, indicating a significant difference in lifting discrepancy according to the kind of relining materials. 2) In terms of the different molds of denture base, 2 kinds of R and E tended to show a little greater lifting discrepancies for thick samples of the alveolar ridge area, compared with the opposite tendency in case of T. 3) In terms of the different materials, combination of A and E (Acron.Eporex-E), and that of B and E (Triad.Eporex-E) showed values of the same order without difference. 4) Standard deviation for T showed a value of about 0.5mm or so, with a greater variation than others.

Survey of human rotavirus serotypes in different locales in Japan by enzyme-linked immunosorbent assay with monoclonal antibodies.

To investigate the relative frequency of individual human rotavirus serotypes prevailing in Japan, 562 stool specimens collected from patients with rotavirus gastroenteritis between November 1986 and March 1988 in seven districts were examined by an enzyme-linked immunosorbent assay (ELISA) with serotype 1-, 2-, 3-, and 4-specific monoclonal antibodies. Serotype 1 was the predominant serotype in the winter of 1986-1987; however, both serotypes 1 and 2 were detected frequently in the winter of 1987-1988. The results showed the relative frequency of individual serotypes by locale and the yearly change in the prevalence of each serotype in the same area. The result of subgroup specificity of rotavirus obtained by using ELISA with subgroup I- and II-specific monoclonal antibodies confirmed the general finding that rotavirus strains having subgroup I specificity are serotype 2 and those having subgroup II specificity are either serotype 1, 3, or 4. Unusual strains having both subgroup I and II specificity or neither specificity and strains presumed to represent new serotypes were also found.