The influence of surface modifications to titanium on the initial adherence of Porphyromonas gingivalis ATCC33277 and Actinobacillus actinomycetemcomitans ATCC43718 was evaluated. Surface modifications were performed with dry processes including ion implantation (Ca(+), N(+), F(+)), oxidation (anode oxidation, titania spraying), ion plating (TiN, alumina), and ion beam mixing (Ag, Sn, Zn, Pt) with Ar(+) on polished pure titanium plates. Comparatively large amounts of P. gingivalis and A. actinomycetemcomitans adhered to polished titanium plates. The degree of P. gingivalis adhesion showed a positive correlation with surface energy and the amount of calcium-ion adsorption. Adherence of both P. gingivalis and A. actinomycetemcomitans increased on calcium-implanted surfaces compared with polished titanium surfaces, whereas adherence of P. gingivalis was remarkably decreased on alumina-coated surfaces. These findings indicate that titanium implants exposed to the oral cavity require surface modification to inhibit the adherence of oral bacteria, and that surface modification with a dry process is useful in controlling the adhesion of oral bacteria as well as ensuring resistance against wear.

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We examined 26 atherosclerotic lesions and 14 nondiseased aorta specimens to detect the periodontopathogenic part of the bacterial 16S rRNA locus by PCR. Treponema denticola sequence of the 16S rRNA locus was found in 6 out of 26 DNA samples (23.1%) from the formalin-fixed, paraffin-embeded atherosclerotic lesions obtained during surgery but not in any of the 14 nondiseased aorta samples from deceased persons. Utilizing immunofluorescence microscopy, we observed aggregated antigenic particles reacting with rabbit antiserum against T. denticola in thin sections of the PCR-positive samples, but we could not detect any reacting particles in the PCR-negative thin sections.Recent epidemiological studies have established that rheological and hemostatic factors are related to vascular diseases. These factors are potential biological effectors which may interact with known risk factors such as hyperlipidemia, smoking, and infections to promote vascular events. A number of studies have suggested that infectious organisms may play a role in the etiology and epidemiology of atherosclerosis and related diseases (5,6,9,29). For one such organism, Chlamydia pneumoniae, there is mounting evidence associating infections with a greater risk of atherosclerosis, myocardial infarction, and chronic coronary heart disease (3,20,26). Persistent infections by the obligate intracellular gram-negative bacteria are involved in a wide spectrum of respiratory diseases. It is now recognized that chronic oral infections, such as adult periodontitis, may have important long-term sequelae (2,7,10,16,19,(21)(22)(23)(24)28). An inflammatory response to endothelial cell injury and dysfunction caused by these infections may lead to atherosclerosis (26). Recently, Haraszthey et al. (11) reported that periodontal organisms such as Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Bacteroides forsythus, and Prevotella intermedia were detected in atheromatous plaque by PCR. In the present study, we attempted to detect periodontopathic bacterial DNA in atherosclerotic vascular lesions.To detect A. actinomycetemcomitans, P. gingivalis, B. forsythus, Campylobacter rectus, and Treponema denticola, we used the PCR and followed a double-blind protocol. The primers for detecting part of the bacterial 16S rRNA locus by PCR were synthesized in accordance with previously reported procedures (1, 30). Primer pairs for T. denticola (5Ј-TAATACCG AATGTGCTCATTTACAT-3Ј and 5-TCAAAGAAGCATTC CCTCTTCTTCTTA-3Ј), B. forsythus (5Ј-GCGTATGTAACC TGCCCGCA-3Ј and 5Ј-TGCTTCAGTGTCAGTTATACCT-3Ј), and C. rectus (5Ј-TTTCGGAGCGTAAAACTCCTTTTC-3Ј and 5Ј-TTTCTGCAAGCAGACACTTTT-3Ј) were designed on the basis of 16S rRNA (1). Primer pairs for P. gingivalis (5Ј-ATAATGGAGAACAGCAGGAA-3Ј and 5Ј-TCTTGCC AACCAGTTCCATTGC-3Ј) and A. actinomycetemcomitans (5Ј-CAGCAAGCTGCACAGTTTGCAAA-3Ј and 5Ј-CATTA GTTAATGCCGGGCCGTCT-3Ј) were designed on the basis of fimbriae and leukotoxin (30). Primer pairs for C. pneumoniae (5Ј-TGACAACTGTAGAAATACAGC-3Ј and 5Ј-GG TTGAGRTCAACGACTTAAGG-3Ј) were designe...

The authors report a study of 92 human embryos and four fetuses with myeloschisis. The characteristics of embryonic myeloschisis compared with spina bifida cystica in infants are: 1) the lesion is often more diffuse, involving the whole spinal cord (12 embryos); 2) the cervical cord is frequently affected (23 of the remaining 80 embryos); 3) holoprosencephaly is frequently associated (18 embryos); 4) meningocele is not found; and 5) hydrocephalus and Arnold-Chiari malformation are not yet developed. Hydrocephalus and Arnold-Chiari malformation are found in myeloschistic fetuses. Almost all embryos with diffuse and cervical myeloschisis or with holoprosencephaly are extruded before birth by spontaneous abortion. Absence of meningocele in the embryonic period implies that its appearance is deferred to the fetal period. The development of hydrocephalus and Arnold-Chiari malformation also seems to be delayed until the fetal period. Our observation implies that myelomeningocele is induced by non-closure of the neural tube, not by rupture once it was closed. "Neural overgrowth" and disturbed "recanalization process" are discussed in relation to the pathogenesis of myelomeningocele.

Our previous study showed that mice fed on a soft diet after weaning had reduced levels of brain-derived neurotrophic factor (BDNF) protein in the hippocampus after 3 months of age compared with mice fed on a hard diet. BDNF is one of the most effective promoters of neurogenesis in the hippocampus, and enhancement of BDNF production has been shown to enhance neural precursor cell proliferation in the dentate gyrus. We hypothesized that soft-diet feeding during development would reduce the proliferation rate of precursor cells, resulting in lower production of new neurons in the hippocampus. Male C57BL/6 mice pups were fed either a solid (hard-diet group) or powdered (softdiet group) diet starting at weaning. Three and six months after birth, mice of each group received intraperitoneal injections of bromodeoxyuridine (BrdU, 50 mg/kg body weight), twice a day for 3 consecutive days. After survival time of 1 day, 1 week, or 4 weeks, the mice were anesthetized and perfused transcardially. Newborn cells in the dentate gyrus were examined by immunohistochemistry using anti-BrdU antibody. In addition, phenotypically neuronal cells among the newborn cells were detected by immunofluorescent double labeling for BrdU and mature neuron-specific nuclear protein (NeuN) using anti-BrdU and anti-NeuN antibodies. Total number of BrdU-positive cells in the dentate gyrus was fewer in the 6-month-old mice than in the 3-month-old mice at any survival time investigated, and fewer in the soft-diet group than in the hard-diet group at 3 and 6 months of age. Neither soft-diet feeding nor aging affected ratio of phenotypically neuronal cells among newborn cells. These results indicate that insufficient mastication activity during development as well as aging restrains hippocampal neurogenesis in adulthood.