Development and Effective Utilization of a Rapid Multiplex Real-Time PCR of Diarrheagenic Escherichia coli for Food Poisoning Cases

Diarrheagenic Escherichia coli (DEC) causes diarrheal symptoms in humans. The comprehensive detection of DEC from feces using SYBR Green real-time PCR assay requires multiple runs. Moreover, PCR screening can have discrepancies related to the conformance between the results from PCR screening and culturing. We aimed to develop a real-time PCR for the comprehensive testing of DEC for diagnostic support that can be used in any general laboratory and proposed its effective utilization. We tested specificity for the designed primer sets using 100 strains. Moreover, screening and isolation of DEC were performed using the proposed multiplex real-time PCR system for 308 fecal samples collected from 37 food poisoning incidences that occurred in Gifu Prefecture, Japan from 2017 to 2019. Furthermore, the factor of discrepant results between PCR screening and culturing was analyzed by quantifying the number of DEC cell and whole E. coli cell using real-time PCR for 47 PCR screening-positive fecal samples. The results obtained from the developed multiplex real-time PCR system were in 99% concordance with those from the conventional techniques. A total of 49 fecal samples were detected with virulence genes for the screening. Of the samples which were positive with virulence genes by PCR screening, 38.3% could not be detected from the strain for bacterial culture. We found that the culturing positive samples were significantly high in numbers for the DEC cells, but no significant difference was noted in the whole E. coli cells with culturing negative samples. The multiplex real-time PCR developed in this study was found to be rapid and practical for DEC testing. The PCR screening for DEC using this method can provide rapid information toward the diagnostic support of DEC infection.

Typing of Mycobacterium tuberculosis Strains in Gifu Prefecture, Japan, Using Variable Number Tandem Repeat Analysis

To investigate the molecular epidemiological characteristics of Mycobacterium tuberculosis strains collected in Gifu Prefecture, Japan, 483 M. tuberculosis clinical isolates were used for Japan Anti-Tuberculosis Association (JATA) 18-variable number tandem repeats (VNTR) analysis during 2015-2019. To estimate the lineages of M. tuberculosis strains, JATA18-VNTR profiles were applied to a maximum a posteriori method. The results revealed that the ancient Beijing subfamily, accounting for 57.3% (277/483) was the most prevalent M. tuberculosis strain. Furthermore, 18 clusters (GC-1-GC-18) were found by minimum spanning tree analysis. The proportion of clustering strains was 9.9% (48/483), and epidemiological links to these clusters were unclear without GC-6 and GC-18. Meanwhile, interestingly, VNTR profiles of GC-7-GC-9 and GC-14 were indistinguishable from the regional epidemic strains of Nagoya City, which has a strong socioeconomic relationship with Gifu Prefecture, but did not match the nationwide epidemic strains. This study suggests that coordinated analyses within prefectures with strong socioeconomic relationships are important.

Characterization and application of newly developed polymorphic microsatellite markers in the Ezo red fox (Vulpes vulpes schrencki)

The Ezo red fox (Vulpes vulpes schrencki), a subspecies endemic to Hokkaido island, Japan, is a known host species for the tapeworm Echinococcus multilocularis. To develop tools for molecular ecological studies, we isolated 28 microsatellite regions from the genome of Ezo red fox, and developed 18 polymorphic microsatellite markers. These markers were characterized using 7 individuals and 22 fecal samples of the Ezo red fox. The number of alleles for these markers ranged from 1 to 7, and the observed heterozygosity, estimated on the basis of the genotypes of 7 individuals, ranged from 0.29 to 1.00. All markers, except DvNok5, were in Hardy-Weinberg equilibrium (P > 0.05), and no linkage disequilibrium was detected among these loci, except between DvNok14 and DvNok28 (P = 0.01). Moreover, six microsatellite loci were successfully genotyped using feces-derived DNA from the Ezo red fox. The markers developed in our study might serve as a useful tool for molecular ecological studies of the Ezo red fox.

Male-biased hermaphrodites in a gynodioecious shrub, Daphne jezoensis

Gynodioecy, a state where female and hermaphrodite plants coexist in populations, has been widely proposed an intermediate stage in the evolutionary pathway from hermaphroditism to dioecy. In the gynodioecy-dioecy pathway, hermaphrodites may gain most of their fitness through male function once females invade populations. To test this prediction, comprehensive studies on sex ratio variation across populations and reproductive characteristics of hermaphrodite and female phenotypes are necessary. This study examined the variation in sex ratio, sex expression, flower and fruit production and sexual dimorphism of morphological traits in a gynodioecious shrub, Daphne jezoensis, over multiple populations and years. Population sex ratio (hermaphrodite:female) was close to 1:1 or slightly hermaphrodite-biased. Sex type of individual plants was largely fixed, but 15% of plants changed their sex during a 6-year census. Hermaphrodite plants produced larger flowers and invested 2.5 times more resources in flower production than female plants, but they exhibited remarkably low fruit set (proportion of flowers setting fruits). Female plants produced six times more fruits than hermaphrodite plants. Low fruiting ability of hermaphrodite plants was retained even when hand-pollination was performed. Fruit production of female plants was restricted by pollen limitation under natural conditions, irrespective of high potential fecundity, and this minimised the difference in resources allocated to reproduction between the sexes. Negative effects of previous flower and fruit production on current reproduction were not apparent in both sexes. This study suggests that gynodioecy in this species is functionally close to a dioecious mating system: smaller flower production with larger fruiting ability in female plants, and larger flower production with little fruiting ability in hermaphrodite plants.

Enhanced Anti-tumour Effect of Cisplatin with Low-voltage Electrochemotherapy in Hamster Oral Fibrosarcoma

The aim of this study was to determine the effects of low-voltage electrochemotherapy with intraperitoneal cisplatin on hamster oral fibrosarcoma. Oral fibrosarcoma was transplanted sub-mucosally into the cheek pouch mucosa of 100 hamsters. After transplantation, the hamsters were randomly divided into four equal groups. These groups received no treatment (D-E-); 2 mg/kg body weight cisplatin treatment without electroporation (D+E-); electroporation without cisplatin treatment (D-E+);or 2 mg/kg body weight cisplatin treatment followed by electroporation (D+E+). Electrical pulse treatment together with cisplatin injection markedly reduced the size of the tumour, whereas cisplatin injection or electrical pulse treatment alone did not. These results clearly indicate that the anti-tumour effect of cisplatin on hamster oral fibrosarcoma was considerably potentiated or enhanced by the administration of local electrical pulses at low voltages.

90 DESTABILIZATION OF COHESIN REC8 CAUSES ANEUPLOIDY AFTER THE SECOND MEIOSIS IN MURINE POST-OVULATORY AGED OOCYTES

We have previously reported that the early embryos derived from post-ovulatory aged oocytes frequently exhibit aneuploidy, resulting from abnormalities in the cleavage apparatus of MII oocytes. Other studies have also described a potential mechanism that results in aneuploidy, which is attributed to the failure of a cell cycle checkpoint. The spindle assembly checkpoint (SAC), which acts during metaphase, is a monitoring system that equally distributes sister chromatids by correctly attaching spindle fibres to the appropriate centromere. Cohesin, a functional protein complex of the SAC, includes the REC8 subunit, and acts as an adhesion factor for sister chromatids. Segregation of sister chromatids occurs following the degradation of the cohesin complex by the separase enzyme. The segregation process can be mediated by meiosis-specific REC8, which contains a recognition site for separase. In this study, we examined the expression of meiosis-specific REC8 protein in murine post-ovulatory aged oocytes, and verified the association with aneuploidy induced during second meiosis. Superovulated oocytes from the ICR mouse strain were aged by culture for 3 to 24 h in vitro. To eliminate the male genome factor, chromosomal analysis was performed using oocytes activated by SrCl2, without fertilization. The expression level of REC8 in oocytes, before and after activation, was analysed by Western blot, using a rabbit anti-REC8 antibody (primary) and horseradish peroxidase-conjugated anti-rabbit antibody (secondary). In the 6- and 12-h aged groups, 23.8% and 40.3% of oocytes, respectively, exhibited aneuploidy after the second meiosis. The rate of aneuploidy in the 12-h aged group was significantly higher than that in the fresh oocyte group (10.3%; P < 0.05). It could be speculated from our previous data that this fact contributed to the occurrence of aneuploidy in early embryos derived from the aged oocytes. In 3-, 6-, 12-, and 24-h aged groups, the results of semiquantitative analysis of REC8 levels in MII oocytes (non-activated) were 1.32 ± 0.38, 1.30 ± 0.58, 1.15 ± 0.21, and 0.98 ± 0.14, respectively. REC8 levels in the 24-h aged group were significantly lower than in the fresh group (1.86 ± 0.56, P < 0.05). The expression levels of REC8 in activated oocytes at 3 and 6 h were 0.53 ± 0.01 and 0.55 ± 0.04, respectively. REC8 levels in the 12-h (1.00 ± 0.03) and 24-h (0.95 ± 0.04) groups were significantly higher than in the fresh group (0.49 ± 0.09; P < 0.05). The significant reduction of REC8 levels at anaphase, after oocyte activation, was not observed in oocytes aged 12 h or more. In MII oocytes, REC8 levels tend to decrease gradually with post-ovulatory age. Destabilisation of the cohesin REC8 subunit may contribute to the nondisjunction of sister chromatids during second meiosis in post-ovulatory aged oocytes, ultimately resulting in aneuploidy.

102 REPEATED OVARIAN STIMULATIONS BY EXOGENOUS GONADOTROPIN COULD ALTER ATP CONTENT AND MITOCHONDRIAL DISTRIBUTION IN MOUSE OOCYTES

Ovarian stimulation (OS) by exogenous gonadotropin enhances the availability of mammalian oocytes but compromises their developmental competence (Combelles and Albertini 2003 Biol. Reprod. 68, 812–821). Recently, several studies have reported mitochondrial function-related abnormalities in oocytes after single and repeated OSs. Because mitochondria can directly influence fertilization outcomes (El Shourbagy et al. 2006 Reproduction 131, 233–245), this study aimed to determine the relationship between mitochondria-related parameters and developmental competence on the basis of ATP content, mitochondrial DNA (mtDNA) copy number, mitochondrial distribution, and IVF results for oocytes after repeated OSs. Ovulated oocytes were recovered from ICR female mice treated with 7.5 IU of eCG and 5 IU of hCG at an interval of 48 h in 1 (control) to 3 stimulation cycles, which were performed at intervals of either 5 or 10 d (n = 15–25 in each treatment group). The ATP content in oocytes was determined using a luminometer and commercial kits (BacTiter-Glo; Promega, WI, USA; n = 15–29 in each treatment group). The mtDNA copy number in oocytes was quantified by performing absolute quantification with real-time PCR (n = 4–8 in each treatment group). Mitochondrial distribution in oocytes stained by rhodamine123 was observed under a confocal microscope (n = 12–26 in each treatment group). These analyses were performed only for morphologically normal oocytes. The data were analyzed by one-way ANOVA, followed by Fisher’s least significant difference, or by the chi-square test. Some mice did not ovulate in the third stimulation cycle for both intervals (5-d interval, 32%; 10-d interval, 80%). The mean numbers of ovulated oocytes gradually decreased with progression of the stimulation cycles. The ATP content of the oocytes significantly decreased both in the second and third stimulation cycles, performed with a 5-d interval (control, 1.038 ± 0.117 pmol; second cycle, 0.852 ± 0.189 pmol; third cycle, 0.932 ± 0.272 pmol). The mean mtDNA copy number in oocytes did not change significantly but varied widely in the third stimulation cycle (control, 146 000 ± 21 000; 5-d interval, 135 000 ± 35 000; 10-d interval: 148 000 ± 50 000; mean ± SD). The mitochondrial staining patterns were classified into homogeneous, aggregation, and perinuclear accumulation. The rates of aggregation and perinuclear accumulation increased after repeated stimulation cycles. The blastocyst rates did not significantly differ among the treatment groups after IVF (75–82%). Repeated OSs not only decreased the number of ovulated oocytes but also caused changes related with mitochondrial function, even in the morphologically normal ovulated oocytes. Translocation of active mitochondria, which are associated with energy production, has some functional correlation with successful pre-implantation development (Suzuki et al. 2006 J. Mamm. Ova. Res. 23, 128–134). Changes in mitochondrial distribution might compensate for the negative effect of the decrease in ATP content and low mtDNA copy number after repeated OSs to help reach the blastocyst stage.

Development of microsatellite markers for Cinnamomum camphora (Lauraceae)

PREMISE OF THE STUDY

Cinnamomum camphora is an evergreen tree distributed in southern Japan, Taiwan, and southeastern China. Because of its vast utilization and cultivation, the natural distribution area of this species has been controversial.

METHODS AND RESULTS

I isolated and characterized 22 microsatellite loci in C. camphora. Levels of polymorphism were evaluated in 104 adult trees from three populations in Japan: Meiji Jingu (Shinto Shrine), Kajiya Plantation, and Manazuru Peninsula. The mean number of alleles per locus ranged from 4.1 to 8.0 among populations. The mean observed and expected heterozygosities per population ranged from 0.53 to 0.60 and 0.55 to 0.68, respectively.

CONCLUSIONS

All of 22 loci showed a clear and strong single band for each allele, and revealed a useful degree of polymorphism. The microsatellite markers described here will be useful to study the history, population dynamics, mating system, and genetic structure of C. camphora.

Effects of Cycloheximide and Actinomycin D on Radiation-induced Apoptotic Cell Death in the Developing Mouse Cerebellum

Effects of cycloheximide and actinomycin D on radiation-induced cell death in the external granular layer (EGL) of the cerebellum were studied in vivo. Newborn mice were exposed to 0.24 Gy gamma-radiation, and dying cells which exhibited pyknosis of nuclei in the EGL were examined at various post-irradiation periods. The number of pyknotic cells began to increase 3 h after irradiation, reached a peak incidence at 6 h, and then gradually fell to the sham-irradiated level by 18 h. When pups were injected with cycloheximide 1 h after irradiation, cell death was suppressed for 6 h, but a peak mortality as high as in the case of radiation alone was attained at 15 h after irradiation. When pups were treated with cycloheximide twice, at 1 and 6 h after irradiation, cell death did not occur for 15 h, but then the incidence rose to a level similar to that after irradiation alone. These findings showed that radiation-induced cell death in the EGL is suppressed by cycloheximide until the chemical is metabolized. Hence, death is by apoptosis which is known to require macromolecular synthesis, and the 'signal' for apoptosis in the cell persists for at least 15 h after irradiation. On the other hand, actinomycin D injected immediately before or after irradiation did not affect the initiation of cell death; actinomycin D alone induced cell death.

104 ASYMMETRICAL DISTRIBUTION OF MITOCHONDRIAL DNA INTO BLASTOMERES OF TWO-AND FOUR-CELL MOUSE EMBRYOS

Mammalian embryos are thought to cleave equally during early development. Therefore, the contents including organelles such as mitochondria (mt) in oocytes are supposed to be delivered symmetrically into each blastomere of the resulting embryo. However, a recent report showed higher oxygen consumption, ATP production, and mt distribution in trophectoderms from mouse blastocysts than that in inner cell masses (Houghton 2006 Differentiation 74, 11–18). We hypothesized that this phenomenon could be preceded by the asymmetrical mt distribution into blastomeres at earlier stages. Oocytes, 2-cell embryos, and 4-cell embryos from BDF1 were measured to determine volumes, ATP contents, and mtDNA copy numbers in the whole egg and individual blastomeres that had been separated in Ca/Mg-free KSOM with added 0.02% EDTA. The volumes of blastomeres were calculated by the sphere volume formula. The ATP contents were determined using a luminometer and commercial kits (BacTiter-Glo, Promega, Madison, WI, USA). The mtDNA copy numbers were quantified absolutely using real-time PCR. The data was analyzed by 1-way ANOVA followed by Fisher's least significant difference test. We found about a 10% difference in volume between the largest and the smallest blastomeres from a 4-cell embryo. At the 4-cell stage, the largest blastomeres were significantly larger than the middle-sized and smallest blastomeres, and the next largest blastomeres were significantly larger than the smallest blastomeres (largest: 41 093 µm3, next largest: 39 671 µm3, middle-sized: 37 725 µm3, smallest: 36 518 µm3; n = 25). The procedure for separation of blastomeres did not significantly reduce theATP contents of embryos. We observed the same pattern of significant differences in theATP contents among the 4 blastomeres at the 4-cell stage (largest: 0.141 pmol, next largest: 0.124 pmol, middle-sized: 0.112 pmol, smallest: 0.098 pmol, n = 27). The largest blastomeres from 4-cell embryos contained about 1.4-fold higherATP than the smallest blastomeres. There was no significant difference in the mtDNA copy numbers in oocytes (n = 7), whole 2-cell embryos (n = 6), whole 4-cell embryos (n = 13), the sum of 2 blastomeres from the same 2-cell embryo (n = 6), and the sum of 4 blastomeres from the same 4-cell embryo (n = 6; 245 071 � 22 696, 267 567 � 30 989, 262 931 � 12 952, 239 717 � 16 813, 247 012 � 16 166, respectively; � SEM). However, the larger blastomere of 2-cell embryo had a higher mtDNA copy number than the smaller blastomeres (largest: 137 100 � 11 493, smallest: 102 617 � 6205; P < 0.05). The largest blastomeres of 4-cell embryo had about 1.4 times (P < 0.05) higher mtDNA copy numbers than the smallest blastomeres (largest: 72 072 � 4112, next largest: 66 198 � 5767, middle-sized: 57 596 � 3922, smallest: 51 146 � 3081). We found differences in volumes, ATP contents, and mtDNA copy numbers among blastomeres from the same embryos at the 4-cell stage. These qualitative differences could be related to embryonic metabolism in mouse early development.

Effects of nifedipine and interleukin-1alpha on the expression of collagen, matrix metalloproteinase-1, and tissue inhibitor of metalloproteinase-1 in human gingival fibroblasts

BACKGROUND AND OBJECTIVE

Nifedipine-induced gingival overgrowth is known to be characterized by fibrosis and some degree of inflammation. However, the molecular mechanism of the fibrosis is not fully understood. The purpose of this study was to investigate in vitro the effects of nifedipine and interleukin-1alpha on the molecules involved in fibrosis, namely type I collagen, matrix metalloproteinase-1 (MMP-1), and tissue inhibitor of metalloproteinase-1 (TIMP-1).

MATERIAL AND METHODS

Four human gingival fibroblast strains, derived from four healthy volunteers, were cultured in media containing nifedipine (1 microg/ml), with or without interleukin-1alpha (0.05 ng/ml). The mRNAs of type I collagen, MMP-1, and TIMP-1 were measured by reverse transcription-polymerase chain reaction (RT-PCR). The proteins of MMP-1 and TIMP-1 were examined by enzyme-linked immunosorbent assay (ELISA), and the ratios of MMP-1 to TIMP-1 proteins were calculated.

RESULTS

The mRNA expression of type I collagen showed no significant change. Both mRNA expression and protein production of MMP-1 were up-regulated by interleukin-1alpha, either alone or in combination with nifedipine, whereas those of TIMP-1 were up-regulated by nifedipine alone or in combination with interleukin-1alpha. The ratio of MMP-1 to TIMP-1 was not changed by nifedipine alone, but it was increased by interleukin-1alpha alone or in combination with nifedipine. However, in two of the four cell strains tested, nifedipine reduced the ratio of MMP-1 to TIMP-1 compared with that for interleukin-1alpha alone.

CONCLUSION

These results suggest that nifedipine may predispose to fibrosis in some individuals in situations where interleukin-1 levels are raised.

Seasonal changes in pollinator activity influence pollen dispersal and seed production of the alpine shrub Rhododendron aureum (Ericaceae)

In alpine ecosystems, microscale variation in snowmelt timing often causes different flowering phenology of the same plant species and seasonal changes in pollinator activity. We compared the variations in insect visitation, pollen dispersal, mating patterns, and sexual reproduction of Rhododendron aureum early and late in the flowering season using five microsatellites. Insects visiting the flowers were rare early in the flowering season (mid-June), when major pollinators were bumblebee queens and flies. In contrast, frequent visitations by bumblebee workers were observed late in the season (late July). Two-generation analysis of pollen pool structure demonstrated that quality of pollen-mediated gene flow was more diverse late in the season in parallel with the high pollinator activity. The effective number of pollen donors per fruit (N(ep)) increased late in the season (N(ep) = 2.2-2.7 early, 3.4-4.4 late). However, both the outcrossing rate (t(m)) and seed-set ratio per fruit were smaller late in the season (t(m) = 0.89 and 0.71, seed-set ratio = 0.52 and 0.18, early and late in the season, respectively). In addition, biparental inbreeding occurred only late in the season. We conclude that R. aureum shows contrasting patterns of pollen movement and seed production between early and late season: in early season, seed production can be high but genetically less diverse and, during late season, be reduced, possibly due to higher inbreeding and inbreeding depression, but have greater genetic diversity. Thus, more pollinator activity does not always mean more pollen movement.

DNA vaccine against hamster oral papillomavirus-associated oral cancer

Previously we developed a carcinogenesis model involving the combination of 9,10-dimethyl-1,2-benzanthracene (DMBA) application with physical wounding of hamster lingual mucosa. The presence of a novel hamster oral papillomavirus (HOPV) was demonstrated and its genome sequenced. In the present study, this HOPV hamster model was used to test whether vaccination with the L1 gene could prevent the development of oral carcinoma. DNA plasmids encoding the L1 gene or the vector alone were injected intramuscularly into 20 vaccinated and 20 control hamsters, respectively. The lingual tips of the hamsters were painted with DMBA for 8 weeks. A portion of the lingual tips was excised, and the tips were then painted daily with DMBA until the animals were killed 13 days later. All control hamsters developed lingual carcinoma, whereas 12 of the L1-vaccinated hamsters showed no lesions. These results suggest that immunization with L1 DNA vaccines may prevent the development of papillomavirus-associated oral cancer.

Enhancement of crude bone morphogenetic protein-induced new bone formation and normalization of endochondral ossification by bisphosphonate treatment in osteoprotegerin-deficient mice

Osteoprotegerin (OPG) is a novel secreted member of the tumor necrosis factor receptor family which plays a crucial role in negative regulation of osteoclastic bone resorption. We investigated both the quantity and quality of heterotopic new bone induced by crude bone morphogenetic protein (BMP) as a means of examining bone metabolism by bisphosphonate administration in OPG-/- mice. Four weeks after implantation of crude BMP, the volume of heterotopic new bone in OPG-/- mice without alendronate was significantly less than in wild-type (WT) mice. Alendronate treatment of OPG-/- mice resulted in enhancement of the volume of heterotopic new bone. Histological findings revealed that WT mice showed normal bone formation with persistent cartilage that was interspersed with islands of bone. In contrast, the cartilage was replaced by trabecular bone and bone marrow adipocytes in OPG-/- mice without alendronate. However, some cartilage was still present in OPG-/- mice with alendronate compared to those without alendronate. All bone formation-related parameters and bone resorption-related parameters were significantly lower in OPG-/- mice with alendronate than in those without alendronate. These findings suggest that in stimulated osteoclastogenesis without OPG, osteoinductive activity induced by crude BMP is inhibited and endochondral ossification induced by crude BMP is accelerated. On the other hand, alendronate treatment of OPG-/- mice caused osteoinductive activity induced by crude BMP to increase and endochondral ossification induced by crude BMP to be decelerated. In conclusion, inhibition of stimulated osteoclastogenesis results in the enhancement of new bone formation and normalization of endochondral ossification.

Effect of a selective agonist for prostaglandin E receptor subtype EP4 (ONO-4819) on the cortical bone response to mechanical loading

The influence of a selective agonist for prostaglandin E receptor subtype EP4 (ONO-4819) on the bone response to mechanical loading was evaluated. Six-month-old female Wistar rats were used and assigned to three groups (n = 12/group): Vehicle administration (EP4-V), low-dose ONO-4819 administration (EP4-L, 3 microg/kg BW), and high-dose ONO-4819 administration (EP4-H, 30 microg/kg BW). ONO-4819 was subcutaneously injected in the back twice a day for 3 weeks. Loads on the right tibia at 39.4 N for 36 cycles at 2 Hz were applied in vivo by 4-point bending every other day for 3 weeks. Whole-body bone mineral content showed a significant difference between EP4-V and EP4-H (P < 0.05). Bone mineral density (BMD) of the total and regional tibia (the region with maximal bending at the central diaphysis) was higher in EP4-H than EP4-V, showing a significant effect of loading (P < 0.001) and ONO-4819 (P < 0.05). BMD of the total femur was higher in EP4-H than EP4-V (P < 0.01) and that of the distal femur was higher in EP4-H than EP4-V (P < 0.001). Histomorphometry of the cortical bone showed that loading increased formation surface (FS/BS), mineral appositional rate (MAR), and bone formation rate (BFR/BS) significantly at the lateral periosteal surface (P < 0.001); however, the effect of ONO-4819 was not significant. At the medial periosteal surface, loading increased the three parameters (P < 0.001) and ONO-4819 increased FS/BS (P < 0.001) and MAR (P < 0.05) significantly. At the endocortical surface, the effects of both loading and ONO-4819 were significant on all three parameters (for loading; FS/BS P < 0.01, MAR P < 0.05, BFR/BS P < 0.03, for ONO-4819 all P < 0.001). It was concluded that ONO-4819 increased cortical bone formation in rats and there was an additive effect on the bone response to external loading by 4-point bending.

Human papillomaviruses in the normal oral cavity of children in Japan

The purpose of this study was to determine the frequency of human papillomavirus (HPV) infections in the normal oral cavity of children in Japan. Oral squamous cell specimens were collected from 77 children (44 boys and 33 girls), aged 3 and 5 years. Extracted DNA was evaluated for HPV infections by polymerase chain reaction (PCR) methods, using consensus primers for the L1 region, specific primers, and direct DNA sequencing analysis. Thirty-seven of 77 specimens (48.1%) were positive for HPV DNA. Positive rates of boys and girls in all specimens were 28.3 (22/77) and 19.5 (15/77)%, respectively. The positive rate in 3-year-old children was 45.2 (14/31)%, and positive rates in boys and girls were 52.6 (10/19) and 33.3 (4/12)%, respectively. The positive rate in 5-year-old children was 50.0 (23/46)%, and positive rates in boys and girls were 48.0 (12/25) and 52.4 (11/21)%, respectively. HPV types were determined by specific PCR and direct DNA sequencing analysis. Frequent HPV types in the specimens of all children were HPV-16 (11/37; 29.7%),-1 (6/37; 16.2%),-2 (6/37; 16.2%),-75 (6/37; 16.2%). The results of the present investigation indicate that many HPVs, including HPV-16 (a high-risk type for cancer), are present in the oral cavity of 3- and 5-year-old children. It is suggested, therefore, that the oral cavity is already a reservoir of HPVs in childhood where later HPV-associated diseases, such as oral cancer and other oral lesions, may develop.

Hemichrome formation observed in human haemoglobin A under various buffer conditions

AIM

To observe hemichrome formation in human haemoglobin A under various buffer conditions.

METHOD

Hemichrome formation of human oxyhaemoglobin A (HbO2) was studied spectrophotometrically in 0.1 m buffer at various temperatures and pH values.

RESULTS

Following autoxidation in ferrous HbO2, it was evident that formation of hemichrome, which tends to precipitate, occurred at various stages during the course of the autoxidation reaction namely at initial, intermediate or final stages, depending on temperature and pH of the solution. By varying temperature of the solution from 35 to 55 degrees C and pH from 4.5 to 10.5, it is shown here that HbO2 exhibits high susceptibility for hemichrome formation and its occurrence is a function of pH, temperature and progress of autoxidation of HbO2. Unlike HbO2 and its separated haemoglobin chains, monomeric bovine heart myoglobin (MbO2) did not easily form hemichrome.

CONCLUSION

These findings provide a clue on the crucial role of haemoglobin molecule for senescent cell recognition or homeostasis in the blood circulation.

The effect of high sugar intake on the development of periradicular lesions in rats with type 2 diabetes

Diabetes mellitus is associated with depression of natural defenses against infection and increases the risk of periodontal disease. However, the effects of diabetes on periradicular tissue, which differs structurally from periodontal tissue, are not known. In this study, we evaluated the effects of type 2 diabetes on the development of periradicular lesions after exposure of the pulp in the left mandibular first molar through the occlusal surface in rats. GK rats with spontaneous non-insulin-dependent diabetes mellitus and Wistar rats (controls) received a normal laboratory diet and either water or a 30% sucrose solution. At both 2 and 4 weeks after pulp exposure, histologic analysis showed that alveolar bone resorption was most severe and the periradicular lesions were largest in diabetic rats given the sucrose solution. These results suggest that the metabolic conditions produced by type 2 diabetes enhance the development of periradicular lesions in rats.

Cytochrome oxidase activity and confocal laser scanning microscopic analysis of the hamster submandibular gland using microwave irradiated fixation

Submandibular glands of the hamster were irradiated in 2% paraformaldehyde (pFA)-0.5% pure glutaraldehyde (PGA) with a microwave (MW) processor at temperatures of 10 degrees and 37 degrees C. Electron microscopy showed that cytochrome oxidase activity was taking place in the mitochondrial intermembrane-intracristal space of the granular duct cell when the temperature of the MW-irradiated fixatives was at 10 degrees C. However, a decrease of this activity was observed when we took care to keep the temperature of the MW-irradiated fixatives at 37 degrees C. The distinct reduction of cytochrome oxidase activity allowed by MW irradiation seems to be due the thermal affects of fixatives. Of course, the possibility cannot be excluded that MW irradiation caused other undetectable membrane damage. Then, we used confocal laser scanning microscopy for the preservation check of the mitochondrial membrane for cytochemistry with MW-irradiated fixation. The fluorescence of rhodamine 123 was observed in the inner spaces of the mitochondria at temperatures of 10 degrees and 37 degrees C. When the same tissues were fixed with 2% pFA using an MW processor as the sole fixative at 10 degrees C, no mitochondrial fluorescence was observed. Cytochrome oxidase activity, by contrast, could be seen in the mitochondrial intermembrane-intracristal spaces in the same condition. Formaldehyde is not the best aldehyde for the purpose of ultrastructural preservation. On the other hand, light and electron microscopy showed that the endogenous peroxidase activity was localized in the nuclear envelope, endoplasmic reticulum, secretory granules, and Golgi apparatus of the hamster submandibular gland using 2% pFA-0.5% PGA fixative with and without MW irradiations at temperatures of 10 degrees and 37 degrees C. Some of the same cells were fixed with only 2% pFA under MW irradiation at 10 degrees C; however, marked diffuseness of the peroxidase activity was observed. Therefore, these results indicated that cytochrome oxidase activity was sensitive to heat with MW-irradiated fixation. Peroxidase activity was very resistant to heat with MW-irradiated fixation but not with pFA solo fixation, therefore, PGA had to be used.

Human papillomavirus type 38 infection in oral squamous cell carcinomas

In this study, 53 paraffin-embedded oral squamous cell carcinoma (OSCC) biopsy specimens were used. Human papillomavirus type 38 (HPV-38) infection was demonstrated in OSCCs using the PCR technique, DNA sequencing analysis, in situ hybridization, and immunohistochemical techniques. Additionally, the correlation between HPV-38 infection and expressions of proliferating cell nuclear antigens (PCNA) or p53 protein was analyzed immunohistochemically. Using consensus primers for the L1 region (L1-PCR), we identified 35 of 53 specimens (66%) as positive for HPV-38 DNA. Furthermore, specimens from patients over 60 years of age revealed a lower prevalence for the HPV-38 (56.7%) than did those below that age (78.3%). Immunohistochemically, positive stainings for PCNA and p53 protein were more frequently detected in HPV-38 positive OSCCs than HPV negative ones. These results indicate that HPV-38 positive OSCCs were higher in proliferative cellular activity than HPV negative ones. Moreover, the findings suggest that HPV-38 infection may cause malignant transformation of the oral mucosal epithelium.

Epithelial cell proliferation in oral lichen planus

Although the pathogenesis of oral lichen planus (OLP) is not clear, a small proportion of cases with OLP are reported to transform to cancer. We examined the epithelial cell proliferation status of OLP to relate the labelling index to microscopic features surveyed routinely in pathology. Mucosal biopsies obtained from 44 cases diagnosed with OLP with an intact oral epithelium and 10 normal control specimens from Japanese subjects were immunohistochemically stained with MIB and p53 antibodies. The Ki67 labelling index (LI) was significantly higher in OLP compared with normal controls. A particularly large number of OLP lesions (64%) were p53 positive. No association was, however, found with p53 expression and the Ki67 LI. Atrophic and flat epithelia had a quantitatively higher LI, which did not significantly differ from acanthotic biopsies. Increased cell proliferation in OLP is likely to be a secondary phenomenon due to the damage inflicted on keratinocytes by infiltrating mononuclear cells in the submucosa.

Ca2+-independent phospholipase A2 activity in apical plasma membranes from the rat parotid gland

An apical-enriched plasma membrane fraction (A-PM) was prepared from rat parotid gland by Mn2+ precipitation. In this fraction, phosphatidylcholine (PC) labelled at the sn-2 position was mainly decomposed into two labelled compounds (free fatty acid and 1,2-diacylglycerol) under Ca2+-free conditions. Studies using double-labelled PC and 2,3-diphosphoglycerate (as a phospholipase D inhibitor) showed that they were produced through different pathways: free fatty acid was released by phospholipase A2 (PLA2) while 1,2-diacylglycerol may be produced by sequential action of phospholipase D and phosphatidate phosphatase. The PLA2 in A-PM did not require Ca2+ for its activity and was highly activated by Triton X-100 and ATP. The inhibitor of the well-documented Ca2+-independent PLA2, bromoenol lactone, did not inhibit the PLA2 activity in A-PM. Although PLA2 activity was detected in other subcellular fractions, the highest specific activity was in A-PM. Its distribution among various fractions was roughly similar to that of the marker enzyme of apical plasma membranes. These findings suggested that Ca2+-independent PLA2 activity is present in apical plasma membranes from rat parotid gland. In addition, to clarify the involvement of the PLA2 in exocytosis, the fusion of exogenous PLA2-treated membranes with secretory granules was examined by fluorescence dequenching assay. This study clearly demonstrated the facilitation of fusion by PLA2 treatment, which suggests some involvement of apical PLA2 in saliva secretion.

Release of mercury from dental amalgam fillings in pregnant rats and distribution of mercury in maternal and fetal tissues

Mercury vapor released from a single amalgam restoration in pregnant rats and mercury concentrations in maternal and fetal rat tissues were studied. Dental treatment was given on day 2 of pregnancy. Mercury concentration in air sample drawn from the metabolism chamber with the rat was measured serially for 24 h on days 2, 8 and 15 of pregnancy. An average mercury concentration in the air samples from the rats given amalgam restorations was 678.6+/-167.5 ng/day on day 2. The average mercury concentration in the air samples tended to decline as time elapsed but a marked amount (423.2+/-121.5 ng/day) was observed even on day 15. The amount of mercury in the air samples increased 7--20-fold after chewing. The placement of the single amalgam restoration (3.8--5.5 mg in weight) increased the levels of mercury approximately three to 6 times in the maternal brain, liver, lung, placenta and 20 times in the kidneys. The highest mercury concentration among fetal organs was found in the liver, followed by the kidneys and brain. Mercury concentrations in maternal organs and fetal liver were significantly higher than those of the controls, and concentrations in maternal whole blood, erythrocytes and plasma, and in fetal whole blood were also significantly higher. Mercury concentrations in the fetal brain, liver, kidneys and whole blood were lower than those of the maternal tissues.

Patterns and levels of gene flow in Rhododendron metternichii var. hondoense revealed by microsatellite analysis

Parentage analysis was conducted to elucidate the patterns and levels of gene flow in Rhododendron metternichii Sieb. et Zucc. var. hondoense Nakai in a 150 x 70 m quadrant in Hiroshima Prefecture, western Japan. The population of R. metternichii occurred as three subpopulations at the study site. Seventy seedlings were randomly collected from each of three 10 x 10 m plots (S1, S2, and S3) on the forest floor of each subpopulation (A1, A2, and A3). Almost all parents (93.8%) of the 70 seedlings were unambiguously identified by using 12 pairs of microsatellite markers. Within the quadrant, adult trees less than 5 m from the centre of the seedling bank (plots S1, S2, and S3) produced large numbers of seedlings. The effects of tree height and distance from the seedling bank on the relative fertilities of adult trees were highly variable among subpopulations because of the differences in population structure near the seedling bank: neither distance nor tree height had any significant effect in subpopulation A1; distance from the seedling bank had a significant effect in subpopulation A2; and tree height had a significant effect in subpopulation A3. Although gene flow within each subpopulation was highly restricted to less than 25 m and gene flow among the three subpopulations was extremely small (0-2%), long-distance gene flow from outside the quadrant reached 50%. This long-distance gene flow may be caused by a combination of topographical and vegetational heterogeneity, differences in flowering phenology, and genetic substructuring within subpopulations.

Fluoride and magnesium concentrations in human dental calculus obtained from Japanese and Chinese patients

Calculus deposited on a total of 68 permanent teeth from patients 30-60 years old from Nagoya in Japan and Beijing in China was investigated. An abrasive microsampling method was used to examine the fluoride (F) and magnesium (Mg) distribution, using a fluoride ion-specific electrode and atomic absorption spectrophotometry, respectively. F concentrations decreased from the surface towards the interior of the calculus. Mg concentrations, however, gradually rose towards the innermost surface adjacent to the tooth. In all parts of the depth profiles, the average concentrations of both magnesium and fluoride were higher in the Japanese than in the Chinese calculus. Towards the inner surface of the calculus, F and Mg concentrations were also much higher in the Japanese than in the Chinese group. A greater intake of sea foods and greater use of fluoride dentifrices are possible reasons for the higher F and Mg concentrations in the Japanese individuals.

Structure and stereochemistry of the higher bile acid isolated from turtle bile: (22S,25R)-3 alpha,12 alpha,15 alpha,22-tetrahydroxy-5 beta-cholestan-26-oic acid

The structure and stereochemistry of the higher bile acid, tetrahydroxyisosterocholanic acid (TISA), which was previously isolated from the bile of Amyda japonica (turtle) and proposed as a tetrahydroxyisosterocholanic acid, have been established as (22S,25R)-3 alpha,12 alpha,15 alpha,22-tetrahydroxy-5 beta-cholestan-26-oic acid by X-ray crystallographic analysis of its ethyl ester.

Seroprevalence of Bartonella henselae and Toxoplasma gondii infections among pet cats in Kanagawa and Saitama Prefectures

Seroprevalence of Bartonella henselae and Toxoplasma gondii was investigated among 471 pet cats obtained from seven private animal hospitals in Kanagawa and Saitama Prefectures during the period from May 1994 to June 1995. 'Furthermore, 67 randomly selected from the 471 serum samples were examined for the feline immunodeficiency virus (FIV) antibody and feline leukemia virus (FeLV) antigen. The antibody to B. henselae was examined by an indirect immunofluorescent antibody test. T. gondii, FIV and FeLV infections in cats were detected with respective commercial kits. Of the cat serum samples tested, 43 (9.1%) were found to be seropositive for B. henselae and 41 (8.7%) for T. gondii. The B. henselae-positive rate (12.9%) of male cats was significantly higher than that (5.2%) of female cats. On the other hand, T. gondii-positive rate was 9.1% in male and 8.7% in female cats and there was no significant difference in the positivity between sexes. The positive rate in each hospital varied from 0 to 19.5% for B. henselae and 4.9 to 18.8% for T. gondii. The ages of B. henselae- and T. gondii-positive cats were distributed from < 1-year-old to 14-year-old and the seropositivity increased with age of cats. Of the 67 cat serum samples, 16 and 6 cases were positive for FIV and FeLV, respectively. There was no relationship between these viral and B. henselae infections in cats.

ATP-mediated activation of Ca2+-independent phospholipase A2 in secretory granular membranes from rat parotid gland

We characterized the Ca2+-independent, membrane-associated phospholipase A2 (PLA2) from rat parotid secretory granules. Among four phosphatidylcholine species with different fatty acyl (palmitoyl, oleoyl, linoleoyl, and arachidonoyl) groups at the sn-2 position, 2-arachidonoyl-phosphatidylcholine was the preferred substrate. Such specificity was also apparent even when 2-arachidonoyl-phosphatidylcholine coexisted with another species. The various well-documented inhibitors of PLA2s, bromoenol lactone, arachidonyl trifluoromethyl ketone, methyl arachidonyl fluorophosphate, and diisopropyl fluorophosphate, did not inhibit granular PLA2 activity. The granular PLA2 was activated markedly by ATP, and to a lesser extent by GTP and ATPgammaS. GTP also partially suppressed the ATP-mediated activation. UTP, CTP, GTPgammaS, and the hydrolyzed products of ATP and GTP showed little activation of the enzyme. Neither addition of K-252a nor depletion of Mg2+ affected ATP-mediated activation. Although this enzyme was located in the granular membranes, the granular soluble contents or BSA were required for the full activity and full ATP-mediated activation. These results suggested that the PLA2 located in granular membranes may participate in the liberation of arachidonic acid in parotid cells and be regulated through a mechanism mediated by ATP.

Presence of a novel hamster oral papillomavirus in dysplastic lesions of hamster lingual mucosa induced by application of dimethylbenzanthracene and excisional wounding: molecular cloning and complete nucleotide sequence

A combination of 9,10-dimethyl-1,2-benzanthracene (DMBA) application and excisional wounding on the lingual tips of Syrian Golden hamsters (Mesocricetus auratus) induces dysplastic and malignant mucosal lesions. Papillomavirus genus-specific antigen and viral particles, measuring 55 nm in diameter, were demonstrated in the nuclei of squamous cells of dysplastic lesions showing koilocytotic change. In this study, we cloned a circular genome at a single Kpnl site from one of these dysplastic lesions. The genomic sequence of this clone, consisting of 7647 bp, was shown to be that of a novel papillomavirus with a conserved genomic organization. We named the new virus hamster oral papillomavirus (HOPV). All dysplastic lesions induced by this combination of DMBA application and excisional wounding contained viral DNA. Although Southern blot hybridization analysis could not detect the HOPV genome, PCR analysis demonstrated the latent HOPV genome in the tongue and skin of an untreated hamster. These results suggest that latently present HOPV genome is reactivated by the DMBA/wounding procedures. Lingual HOPV infection may be an important model for gaining insight into the interactions between papillomavirus infection, chemical carcinogens and physical irritations in carcinogenesis or malignant transformation.

Biodiscrimination of alpha-tocopherol stereoisomers in humans after oral administration

We investigated changes in the concentrations of the stereoisomers of alpha-tocopherol in serum and lipoproteins in seven normal, healthy women aged 21-37 y who had received oral administration of natural and synthetic alpha-tocopheryl acetate. This study was conducted in three separate periods of 28 d each; there was a 3-mo washout period between each experimental period. During the first period the subjects were administered a daily dose of 100 mg RRR-alpha-tocopherol/d, whereas in the second and third periods 100 mg all-rac-alpha-tocopheryl acetate/d and 300 mg all-rac-alpha-tocopheryl acetate/d were given, respectively. Blood samples were collected 3 d before each treatment and 1, 3, 7, 14, and 28 d after treatment. alpha-Tocopherol stereoisomer concentrations in serum and lipoproteins (very-low-, low-, and high-density lipoproteins) were determined by the chiral HPLC method. The bioavailability of RRR-alpha-tocopherol was greater than that of all-rac-alpha-tocopheryl acetate. When bioavailability was estimated from the increase in the concentration of RRR- or all-rac-alpha-tocopherol in serum, bioavailability of RRR-alpha-tocopherol administered at 100 mg/d was not different from that of all-rac-alpha-tocopheryl acetate administered at 300 mg/d. 2R-Isomers and small amounts of 2S-isomers were detected in the serum lipoproteins of subjects administered all-rac-alpha-tocopheryl acetate.

Disinfection of removable dentures using ozone

Over time, removable dentures tend to become unsanitary and emit unpleasant odors, and oral mucosa sometimes becomes inflamed or denture stomatitis is caused by denture plaque. Recently, various cleaning products designed to keep removable dentures sanitary have appeared on the market. It is known that denture plaque is mainly composed of Candida albicans (C. albicans), and that ozone seems to inhibit these micro-organisms. Accordingly, a denture cleaner using ozone bubbles (ozone concentration of about 10 ppm) was considered as clinically appropriate because of its strong disinfecting and deodorizing power, and high biological safeness. The effectiveness of this cleaner against C. albicans was investigated using. Results showed that C. albicans decreased to about 1/10 after 30 min and to 1/10(3) after 60 min.

An improved method of alkaline sucrose density gradient sedimentation to detect less than one lesion per 1 Mb DNA

We improved alkaline sucrose density gradient sedimentation to detect very long single-strand DNA at the megabase level (from less than 1 to about 4 Mb). Hitherto, these have not sedimented correctly due to some artifacts. One artifact was aggregation of sticky DNA and proteins formed in the gradient. Then, in some gradients, biphasic distribution was observed, the major peak of which was reasonable as a result of random scission by X-rays, but the minor, fast-sedimenting population was another artifact resulting from incomplete denaturation of the DNA. We mainly reduced the centrifugal force and used a solution for cell lysis with a high concentration of salt. By means of this procedure, DNA single-strand breaks induced by relatively low doses of X-rays and subsequent repair processes can be measured in human fibroblasts. The protocol is also applicable to the study of DNA damage accompanied by strand scission, such as by UV or dimethyl sulfate as well as their repair. The technique is sensitive enough to detect even single-strand breaks induced by 0.1 J/m2 UV and sufficiently reproducible that breaks induced by increasing UV dosages were dose dependent. Thus, this technique was proven to be very sensitive, reliable and simple to perform. Therefore, this improvement will be extremely useful to investigators studying DNA repair.

Microsomal diacylglycerol acyltransferase in rat parotid and submandibular glands: acylation of 1,2-dioleoyl-sn-glycerol dispersed with phospholipids

In order to investigate microsomal diacylglycerol acyltransferase activity, ethanol or several detergents have been used as a dispersing agent for water-insoluble substrates. However, ethanol acyltransferase interferes with the activity of this enzyme, and detergents inhibit it. We examined the properties of microsomal diacylglycerol acyltransferase in rat salivary glands without detergents or organic solvents. 1,2-Dioleoyl-sn-glycerol (1,2-diolein) was dispersed by sonication. The activity was measured as the formation rate of [14C]triglyceride using [1-14C]palmitoyl-CoA as an acyl-donor. The reaction was dependent on the microsomal protein and 1,2-diolein at least up to 145 micrograms/ml and 3.6 mM, respectively. The specific activities were 3.91 +/- 0.57 and 3.80 +/- 0.77 nmol/min per mg protein (SEM, n = 4) in the parotid and submandibular glands, respectively. They were 12- to 20-fold higher than the activities in liver, brain and spleen, and two orders of magnitude higher than that assayed with microsomal endogenous diacylglycerol. Adding tissue phospholipids to 1,2-diolein suspension reduced the concentration of 1,2-diolein required for the maximal velocity. A similar, but reduced, effect was induced by egg yolk phosphatidylcholine in place of the tissue phospholipids. The level of activity was recovered by adding another phospholipid class to the phosphatidylcholine. The results suggested that the physical condition of the substrate diacylglycerol affects diacylglycerol acyltransferase activity in rat salivary gland microsomes.

Substrate specificity of microsomal 1-acyl-sn-glycero-3-phosphoinositol acyltransferase in rat submandibular gland for polyunsaturated long-chain acyl-CoAs

Microsomal 1-acyl-sn-glycero-3-phosphoinositol (1-acyl-GPI) acyltransferase in the rat submandibular gland showed the highest specific activities for eicosanoid-related polyunsaturated acyl-CoAs, such as arachidonoyl-, bishomo-gamma-linolenoyl- and 5,8,11,14,17-eicosapentaenoyl-CoAs, with low Km values. High activities were also obtained with acyl-CoAs having long (more than 14 carbon atoms) and n - 6 unsaturated (more than 3 double bonds) acyl chains. This enzyme also utilized acyl-CoAs having trans-unsaturated or branched chains, but not short-chains, as substrates, although the activity levels for trans-unsaturated acyl-CoAs were lower than those for cis-unsaturated acyl-CoAs. Chronic administration of isoproterenol induced decreases of this enzyme activity and the content of arachidonic, bishomo-gamma-linolenic and 5,8,11,14,17-eicosapentaenoic acids at the sn-2 position of phosphatidylinositol. These results suggest that enrichment of arachidonic acid in the sn-2 position of phosphatidylinositol is established by the high specificity and affinity of 1-acyl-GPI acyltransferase for arachidonoyl-CoA. On the other hand, the low level of bishomo-gamma-linolenic and 5,8,11,14,17-eicosapentaenoic acids in the sn-2 position of phosphatidylinositol may be explained by their limited availability.

The significance of membrane lipids in exocytosis: control of liposome-evoked amylase release from secretory granules isolated from the rat parotid gland

We investigated the significance of the plasma membrane lipid composition in exocytosis in an in vitro interaction system using an intact secretory granular fraction (SG) isolated from the rat parotid gland. When various liposomes (as a model of plasma membranes) were added to this assay system, rapid and transient amylase release from the SG was evoked and increased by Ca2+ in a concentration-dependent manner. The extent depended upon not only the amount of liposomes but also their lipid composition. The addition of 1,2-diacylglycerol and phosphatidic acid to egg yolk phosphatidylcholine-liposomes remarkably facilitated the release. On the other hand, that of various free fatty acids had different effects depending upon their molecular species. Furthermore, a fluorescence de-quenching study demonstrated that membrane fusion actually occurred in this interaction system, and appeared to correlate with the amylase release. These results suggest that the transient alteration of the membrane lipid composition upon cell activation is a modulator of the exocytotic membrane interaction.

Effect of traumatic occlusion on periapical lesions in rats

The effect of traumatic occlusion on periapical lesions in rats was investigated histologically and histometrically. Rats were divided equally into groups A to D. Rats in group A received no treatment; in group B, rats received pulpal exposure of the left mandibular first molar; in group C, a resin plate was cemented onto the occlusal surface of the corresponding maxillary molar; and in group D, the molar pulp was exposed and the resin plate was installed. At 1 and 2 wk, compression of the periodontal ligament and inflammation were less in group D than in group B. Lesions in the periapical periodontal ligament at 1, 2, and 4 wk in group D were significantly smaller than those in group B. This study suggests that traumatic occlusion delayed the enlargement of the periapical lesions in rats.

Long-term treatment with dimethylthiourea inhibits the development of autoimmune disease in NZB x NZWF1 mice

Long-term treatment with dimethylthiourea (DMTU), a scavenger of hydroxyl radical (.OH) and hypochlorous acid (HOCl), suppressed the age-related development of autoimmune disease in NZB x NZWF1 mice. Treatment reduced autoantibody production, retarded increase in blood urea nitrogen, and prolonged life. The results suggest that .OH and HOCl may, at least in part, enhance the development of autoimmune diseases in NZB x NZWF1 mice.

Effect of stopping fluoride administration on the distribution profiles of fluoride in three different kinds of rat bones

The aim of this work was to explore the reduction of fluoride concentrations in the skeleton after stopping experimental fluoride administration. Fluoride was administered to the rats at varying doses (0, 50, 100 ppm in drinking water) and for different lengths of time (4, 13, 25 weeks). A series of fluoride concentrations across the full thickness of humerus, parietal bone, and vertebra arch in rats were measured by means of an abrasive micro-sampling technique. The distribution profiles of fluoride from periosteal to endosteal surfaces, which were apparently related to the histological structure of these bones, were U shaped in the humerus, V shaped in the parietal bone, and W shaped in the vertebra arch. The average fluoride concentrations in the bones increased significantly with each increasing dose and length of fluoride administration. The relative increments were similar between the different regions or the different bones. After stopping fluoride administration, on the other hand, the relative reduction of the average fluoride concentrations in the bones were 30-100%. They were greatly related to the length after stopping fluoride administration and the dose and length of fluoride administration, but also dependent upon the type of bone and the region examined.

Effect of long-term methotrexate-induced neutropenia on experimental periodontal lesion in rats

The effects of long-term methotrexate (MTX)-induced neutropenia on the periodontal lesion in rats were investigated histologically, histometrically and bacteriologically. A nylon thread was inserted into the interdental gingiva between the 1st and 2nd right maxillary molars of the animals 3 weeks before an application of MTX. The animals were then divided into Groups A and B. Group B were injected intraperitoneally with 1.0 mg/kg of MTX 3 times per week for 9 weeks. Group A received saline as a control. Five animals were killed at the 1st, 3rd, 5th, 7th, and 9th week. In Group A, the neutrophils did not decrease during these 9 weeks. In Group B, however, the neutrophils decreased during the 3rd to 9th week. Whereas the experimental side of Group A showed only moderate alveolar bone resorption between the 7th and 9th week, [in Group B] a marked alveolar bone resorption occurred in Group B occurred in the same period. Alveolar bone loss in the experimental side of Group B was significantly greater (p < 0.01) than in Group A in the 7th to 9th weeks. The percentage of gram-negative rods increased in both control and experimental sides of Group at the 9th week. The results of the present study indicate that neutropenia is induced by a long-term application of MTX in rats and that alveolar bone destruction increases as time goes by in the area where a nylon thread was inserted.

Effect of fluoride on root resorption caused by mechanical injuries of the periodontal soft tissues in rats

The present study was carried out to investigate histologically and histometrically the effect of fluoride on root resorption induced by mechanical injuries of the periodontal soft tissues in rats. Resorption lacuna in the root surface of the molar in animals given both mechanical injuries and fluoride administration was significantly smaller in length and area than that in animals given only mechanical injuries. Moreover, resorption lacuna in the former animals contained fewer odontoclasts than that in the latter. The results of the present study might suggest that the administration of fluoride suppressed root resorption induced by mechanical injuries of the periodontal soft tissues.

Irritating effect of formocresol after pulpectomy in vivo

A study was carried out to investigate the effect of formocresol (formalin-creosote) on the periapical tissue after pulpectomy in rats. A pulpectomy was performed on the mesial root of the right mandibular first molar, and, in group A, a paper point containing saline was inserted into the root canal. In group B, a paper point containing formocresol was inserted, and in group C, a drop of formocresol was applied and a paper point containing formocresol was inserted into the root canal. The periapical tissue was examined histologically and histometrically at 3, 7, 14, and 28 days after insertion, and the inflammatory cells and fibroblasts in the apical granulation tissue were also counted. Histologically, in group A, the inflammation observed was slight at 14 and 28 days, while in groups B and C, a moderate inflammation remained. Histometrically, the area of the apical periodontal ligament in groups B and C was increased significantly compared with that in group A at 14 and 28 days. The inflammatory cell count in groups B and C increased significantly compared with that in group A at 7, 14, and 28 days, whereas the fibroblast count in Groups B and C decreased compared with that in Group A at 7, 14, and 28 days. These results demonstrate that formocresol delayed the healing of periapical tissue after pulpectomy.

Suppression of development of glomerulonephritis in NZB x NZWF1 mice by persistent infection with lactic dehydrogenase virus: relations between intercellular adhesion molecule-1 expression on endothelial cells and leucocyte accumulation in glomeruli

The development of glomerulonephritis (GN) in autoimmune NZB x NZWF1 mice was suppressed by persistent lactic dehydrogenase virus (LDV) infection. In this study the expression of intercellular adhesion molecule-1 (ICAM-1) on endothelial cells in glomeruli was examined during the development of GN. ICAM-1 expression on endothelial cells preceded the accumulation of leucocytes within glomeruli. The uninfected mice exhibited an age-related and profound increase in ICAM-1 expression associated with the development of a GN as evidenced by deposits of IgG and C3. Uninfected mice also showed increased accumulation of leucocytes, such as polymorphonuclear leucocytes (PMNs), macrophages, T and CD4+ cells, which express the lymphocyte function-associated antigen-1 (LFA-1) within glomeruli during the development of GN. These changes were strongly suppressed by LDV infection. Our findings suggest that the expression of ICAM-1 in glomerular endothelial cells may, at least in part, contribute to the development of GN. Suppressed expression of ICAM-1 in LDV-infected mice may be responsible for the suppression of GN seen in these animals. Thus there may be a pathogenetic role for ICAM-1 expression and for intraglomerular accumulation of leucocytes, especially PMNs, which express LFA-1 in the development of GN.

Changes in microsomal lysophospholipid acyltransferase activity are correlated with rat parotid gland enlargement induced by chronic administration of isoproterenol

Chronic (5- and 10-day) administration of isoproterenol, an agent that induces the proliferation of salivary gland cells, produced increases in microsomal 1-acyl-sn-glycero-3-phosphate acyltransferase and 1-acyl-sn-glycero-3-phosphocholine acyltransferase activity in rat parotid glands in parallel with gland enlargement. This increased activity was reduced when the treatment was stopped, the reduction corresponding to the reduction in gland weight. There were significant correlations between lysophospholipid acyltransferase activity and gland weight, and between the activities of the two types of lysophospholipid acyltransferase. However, isoproterenol treatment did not affect any of the steps of the subsequent phospholipid N-methylation. These results suggest that the cell proliferation induced by chronic administration of isoproterenol in the parotid gland is accompanied by reversible and selective increases in microsomal lysophospholipid acyltransferases.

[Effect of isoflurane and sevoflurane on evoked potentials and EEG]

Evoked potentials and EEG are used to monitor the central nervous system and the depth of anesthesia in anesthetized patients. In this study, we examined EEG, VEP, SEP and ABR at various concentrations of isoflurane or sevoflurane, and evaluated the influence of volatile agents and their usefulness for the monitoring of the depth of anesthesia. With increasing concentrations of isoflurane and sevoflurane, AE (frequency which account for 80% of total voltage) showed dose-related reduction and EEG showed a trend toward a slower wave and higher amplitude. With increasing concentrations of isoflurane and sevoflurane, P100 of VEP showed a significant dose-related reduction in its amplitude and increase in its latency. So we could not record P100 at the level of the anesthesia of 1.0 MAC with 66% N2O. N20 of SEP can be easily recorded at any depth of anesthesia. And the trend showed consistent dose-related changes in amplitude and latency. With increasing concentrations of isoflurane and sevoflurane, wave III and V of ABR increased significantly in latency, but the changes were very small. In conclusion, the effect of isoflurane and that of sevoflurane on evoked potentials and EEG are similar with each other and with other volatile agents. SEP is the most consistent and reliable factor to monitor the depth of anesthesia neurophysiologically.

Reduced streptozotocin-induced insulitis in CD-1 mice by treatment with anti-intercellular adhesion molecule-1 and anti-lymphocyte function associated antigen-1 monoclonal antibodies together with lactic dehydrogenase virus infection

Multiple low-dose streptozotocin (SZ)-induced insulitis is an animal model for insulin-dependent diabetes mellitus characterized by a mononuclear cell infiltration. SZ-induced insulitis and blood glucose concentrations were reduced by treatment with anti-intercellular adhesion molecule-1(ICAM-1) and anti-lymphocyte function associated antigen-1 (LFA-1) monoclonal antibodies. This suppressing effect was also seen in mice infected with lactic dehydrogenase virus (LDV). These results suggest that the expression of ICAM-1 in islets and LFA-1 on mononuclear cells may be important in the development of SZ-induced insulitis. The suppressive effect of LDV infection on the development of insulitis is discussed.