Keratinocyte-specific ablation of Stat3 exhibits impaired skin remodeling, but does not affect skin morphogenesis

To elucidate the biological role of Stat3 in the skin, conditional gene targeting using the Cre-loxP system was performed as germline Stat3 ablation leads to embryonic lethality. K5-Cre;Stat3(flox/-) transgenic mice, whose epidermal and follicular keratinocytes lack functional Stat3, were viable and the development of epidermis and hair follicles appeared normal. However, hair cycle and wound healing processes were severely compromised. Furthermore, mutant mice expressed sparse hair and developed spontaneously occurring ulcers with age. Growth factor-dependent in vitro migration of Stat3-disrupted keratinocytes was impaired despite normal proliferative responses. We therefore conclude that Stat3 plays a crucial role in transducing a signal required for migration but not for proliferation of keratinocytes, and that Stat3 is essential for skin remodeling, including hair cycle and wound healing.

Determination of 16S rRNA sequences of Streptococcus mitis and Streptococcus gordonii and phylogenetic relationships among members of the genus Streptococcus

We determined the 16S rRNA sequences of the type strains of Streptococcus mitis and Streptococcus gordonii and calculated the phylogenetic distances between those organisms and other members of the genus Streptococcus. The viridans group streptococci were separated into five phylogenetic groups; we named these groups the anginosus group, the mitis group, the salivarius group, the bovis group, and the mutans group. S. mitis and S. gordonii clustered in the mitis group together with Streptococcus pneumoniae, Streptococcus oralis, Streptococcus sanguis, and Streptococcus parasanguis at levels of sequence homology of more than 96%. Within this group, S. mitis, S. oralis, and S. pneumoniae exhibited more than 99% sequence homology with each other, although the DNA-DNA similarity values for their total chromosome DNAs were less than 60%.

Mouse Pitx2 deficiency leads to anomalies of the ventral body wall, heart, extra- and periocular mesoderm and right pulmonary isomerism

Pitx2, a bicoid-related homeobox gene, is involved in Rieger's syndrome and the left-right (L-R) asymmetrical pattern formation in body plan. In order to define the genomic structure and roles of Pitx2, we analyzed the genomic structure and generated Pitx2-deficient mice with the lacZ gene in the homeobox-containing exon of Pitx2. We were able to show that among three isoforms of Pitx2, Pitx2c shows asymmetrical expression whereas Pitx2a, Pitx2b and Pitx2c show symmetrical expression. In Pitx2(-)(/)(-) embryos there was an increase in mesodermal cells in the distal end of the left lateral body wall and an amnion continuous with the lateral body wall thickened in its mesodermal layer. These changes resulted in a failure of ventral body wall closure. In lung and heart in which Pitx2 is expressed asymmetrically, right pulmonary isomerism, atrioventricular canals with prominent swelling, and juxtaposition of the atrium were detected. The hearts failed to develop tricuspid and mitral valves and a common atrioventricular valve forms. Further, dysgenesis of the Pitx2(-)(/)(-) extraocular muscle and thickening of the mesothelial layer of cornea were observed in the ocular system where Pitx2 is expressed symmetrically, and these resulted in enophthalmos. The present study shows that Pitx2 expressed in various sites participates in morphogenesis through three types of actions: the involvement of asymmetric Pitx2 expression in the entire morphogenetic process of L-R asymmetric organs; the involvement of asymmetric Pitx2 expression in the regional morphogenesis of asymmetric organs; and finally the involvement of symmetric Pitx2 expression in the regional morphogenesis of symmetric organs.

Leptin as a modulator of sweet taste sensitivities in mice

Leptin acts as a potent inhibitory factor against obesity by regulating energy expenditure, food intake, and adiposity. The obese diabetic db/db mouse, which has defects in leptin receptor, displays enhanced neural responses and elevated behavioral preference to sweet stimuli. Here, we show the effects of leptin on the peripheral taste system. An administration of leptin into lean mice suppressed responses of peripheral taste nerves (chorda tympani and glossopharyngeal) to sweet substances (sucrose and saccharin) without affecting responses to sour, salty, and bitter substances. Whole-cell patch-clamp recordings of activities of taste receptor cells isolated from circumvallate papillae (innervated by the glossopharyngeal nerve) demonstrated that leptin activated outward K(+) currents, which resulted in hyperpolarization of taste cells. The db/db mouse with impaired leptin receptors showed no such leptin suppression. Taste tissue (circumvallate papilla) of lean mice expressed leptin-receptor mRNA and some of the taste cells exhibited immunoreactivities to antibodies of the leptin receptor. Taken together, these observations suggest that the taste organ is a peripheral target for leptin, and that leptin may be a sweet-sensing modulator (suppressor) that may take part in regulation of food intake. Defects in this leptin suppression system in db/db mice may lead to their enhanced peripheral neural responses and enhanced behavioral preferences for sweet substances.

Molecular genetic identification of a candidate receptor gene for sweet taste

A cDNA clone encoding a novel member of the putative taste receptor T1R family, designated T1R3, was isolated from circumvallate papillae of the mouse tongue using degenerate primers. Reverse transcription-polymerase chain reaction analysis showed predominant expression of the receptor in circumvallate papillae. In situ hybridization analysis revealed that T1R3 was expressed in a subset of taste receptor cells in taste buds and that the topographic distribution of T1R3 in various taste papillae was different from those of the other T1R members. Genetic mapping of T1R3 with a mouse/hamster radiation hybrid panel located the gene on the distal end of mouse chromosome 4 correlated with the Sac locus affecting sweet sensitivity of mice. Our results indicate that T1R3 may serve as the receptor for sweet perception in mice.

Reliability and validity of the Japanese version of the Zarit Caregiver Burden interview

Despite a rapid increase in disabled elderly in Japan, the burden of the caregiver has not been properly assessed due to a lack of objective measurements. Our study was aimed at adapting and validating the Zarit Caregiver Burden Interview (ZBI) in Japan, which is one of the most widely used measurements for caregivers' burden in the United States. Sixty-six caregivers answered the self-administered questionnaire, involving the Japanese version of the ZBI and questions regarding their caregiving situation. Our study demonstrated that the Japanese version of the ZBI had equally as high reliability and validity as the original version. The Japanese ZBI had a high test-retest reliability (r = 0.76) and internal consistency (Cronbach's alpha = 0.93). The total score of the ZBI was highly correlated with the caregivers' score of the Center for Epidemiologic Studies Depression Scale (CES-D) score (r = 0.50), as well as a single global rating of burden (r = 0.71). It was also shown that demographic distribution of the score of the Japanese version had a similar trend to that of the original version. Caregivers who looked after patients with behavioral disturbances were found to have a significantly higher ZBI score than those who looked after patients without behavioral disturbances, which is consistent with previous findings. It is concluded that the Japanese version of the ZBI can be used to measure feelings of burden of caregivers in the Japanese population and can be used for cross-cultural comparison.

Flow-induced dilation of human coronary arterioles: important role of Ca(2+)-activated K(+) channels

BACKGROUND

Flow-induced vasodilation (FID) is a physiological mechanism for regulating coronary flow and is mediated largely by nitric oxide (NO) in animals. Because hyperpolarizing mechanisms may play a greater role than NO in the microcirculation, we hypothesized that hyperpolarization contributes importantly to FID of human coronary arterioles.

METHODS AND RESULTS

Arterioles from atria or ventricles were cannulated for videomicroscopy. Membrane potential of vascular smooth muscle cells (VSMCs) was measured simultaneously. After constriction with endothelin-1, increases in flow induced an endothelium-dependent vasodilation. Nomega-Nitro-L-arginine methyl ester 10(-4) mol/L modestly impaired FID of arterioles from patients without coronary artery disease (CAD), whereas no inhibition was seen in arterioles from patients with CAD. Indomethacin 10(-5) mol/L was without effect, but 40 mmol/L KCl attenuated maximal FID. Tetraethylammonium 10(-3) mol/L but not glibenclamide 10(-6) mol/L reduced FID. Charybdotoxin 10(-8) mol/L impaired both FID (15+/-3% versus 75+/-12%, P<0.05) and hyperpolarization (-32+/-2 mV [from -28+/-2 mV after endothelin-1] versus -42+/-2 mV [-27+/-2 mV], P<0.05). Miconazole 10(-6) mol/L or 17-octadecynoic acid 10(-5) mol/L reduced FID. By multivariate analysis, age was an independent predictor for the reduced FID. Conclusions-We conclude that shear stress induces endothelium-dependent vasodilation, hyperpolarizing VSMCs through opening Ca(2+)-activated K(+) channels in human coronary arterioles. In subjects without CAD, NO contributes to FID. NO and prostaglandins play no role in patients with CAD; rather, cytochrome P450 metabolites are involved. This is consistent with a role for endothelium-derived hyperpolarizing factor in FID of the human coronary microcirculation.

Conventional multiple or microdissection testicular sperm extraction: a comparative study

BACKGROUND

Testicular sperm extraction (TESE) with ICSI is becoming the first-line treatment for non-obstructive azoospermia (NOA). Recently, the sperm retrieval rate (SRR) by microdissection TESE was reported to be higher than by conventional TESE. However, a comprehensive comparison between multiple and microdissection TESE patients including histological findings has not been reported.

METHODS

Patients with NOA who underwent microdissection TESE (n = 56) or multiple TESE (n = 37) were compared. Pre-operative characteristics were similar between groups. In addition, microscopic findings during microdissection TESE also were investigated.

RESULTS

Operative time was significantly longer for microdissection TESE than for multiple TESE. Histological examination suggested that spermatogenesis was relatively more impaired in the microdissection TESE group than in the multiple TESE group. Despite this, SRR by microdissection TESE (42.9%) appeared higher than by conventional TESE (35.1%) although this observation failed to reach statistical significance. Seventeen of 26 patients (65.4%) with heterogeneous tubule were successful for sperm retrieval. No severe operative complications occurred in any patient in either group, and no patient required post-operative hormone replacement to treat hypogonadism.

CONCLUSIONS

Microsurgical technique is safe and may improve SRR for TESE in a variety of patients with NOA, especially patients with heterogeneous testicular tubules.

The Emerging Risk Factors Collaboration: analysis of individual data on lipid, inflammatory and other markers in over 1.1 million participants in 104 prospective studies of cardiovascular diseases

Many long-term prospective studies have reported on associations of cardiovascular diseases with circulating lipid markers and/or inflammatory markers. Studies have not, however, generally been designed to provide reliable estimates under different circumstances and to correct for within-person variability. The Emerging Risk Factors Collaboration has established a central database on over 1.1 million participants from 104 prospective population-based studies, in which subsets have information on lipid and inflammatory markers, other characteristics, as well as major cardiovascular morbidity and cause-specific mortality. Information on repeat measurements on relevant characteristics has been collected in approximately 340,000 participants to enable estimation of and correction for within-person variability. Re-analysis of individual data will yield up to approximately 69,000 incident fatal or nonfatal first ever major cardiovascular outcomes recorded during about 11.7 million person years at risk. The primary analyses will involve age-specific regression models in people without known baseline cardiovascular disease in relation to fatal or nonfatal first ever coronary heart disease outcomes. This initiative will characterize more precisely and in greater detail than has previously been possible the shape and strength of the age- and sex-specific associations of several lipid and inflammatory markers with incident coronary heart disease outcomes (and, secondarily, with other incident cardiovascular outcomes) under a wide range of circumstances. It will, therefore, help to determine to what extent such associations are independent from possible confounding factors and to what extent such markers (separately and in combination) provide incremental predictive value.

Expression of a novel aristaless related homeobox gene 'Arx' in the vertebrate telencephalon, diencephalon and floor plate

We have isolated a novel homeobox gene that is expressed in the vertebrate central nervous system and which shows striking similarity to the Drosophila al gene in the homeodomain (85% identity) and in a 17 amino acid-sequence near the carboxyl-terminus. This gene was designated Arx (aristaless related homeobox gene) in consideration of its structural similarity to the al gene. Arx was highly conserved between mouse and zebrafish. Neuromeric expression in the forebrain and longitudinal expression in the floor plate were observed in mouse and zebrafish. The expression of Arx in the ganglionic eminence and ventral thalamus overlapped regionally with that of Dlx1, but the cell layer where Arx is expressed differed from that of the Dlx1. This gene was also found to be expressed in the dorsal telencephalon (presumptive cerebral cortex) of mouse embryos. The structure and expression pattern of Arx with respect to any possible relationship to al and Dlx1, as well as the function of Arx in the floor plate are discussed.

Dynamic activity dependence of in vivo normal knee kinematics

Dynamic knee kinematics were analyzed for normal knees in three activities, including two different types of maximum knee flexion. Continuous X-ray images of kneel, squat, and stair climb motions were taken using a large flat panel detector. CT-derived bone models were used for model registration-based 3D kinematic measurement. Three-dimensional joint kinematics and contact locations were determined using three methods: bone-fixed coordinate systems, interrogation of CT-based bone model surfaces, and interrogation of MR-based articular cartilage model surfaces. The femur exhibited gradual external rotation throughout the flexion range. Tibiofemoral contact exhibited external rotation, with contact locations translating posterior while maintaining 15 degrees to 20 degrees external rotation from 20 degrees to 80 degrees of flexion. From 80 degrees to maximum flexion, contact locations showed a medial pivot pattern. Kinematics based on bone-fixed coordinate systems differed from kinematics based on interrogation of CT and MR surfaces. Knee kinematics varied significantly by activity, especially in deep flexion. No posterior subluxation occurred for either femoral condyle in maximum knee flexion. Normal knees accommodate a range of motions during various activities while maintaining geometric joint congruency.

Human coronary arteriolar dilation to bradykinin depends on membrane hyperpolarization: contribution of nitric oxide and Ca2+-activated K+ channels

BACKGROUND

K+ channel activation in vascular smooth muscle cells (VSMCs) plays a key role in regulating vascular tone. It has been proposed that endothelium-derived hyperpolarizing factor (EDHF) contributes to microvascular dilation more than nitric oxide (NO) does. Whether hyperpolarization is important for coronary arteriolar dilation in humans is not known. Bradykinin (BK), an endogenous vasoactive substance, is released from ischemic myocardium and regulates coronary resistance. Therefore, we tested the effects of inhibiting NO synthase, cyclooxygenase, and K+ channels on the changes in diameter and membrane potential (Em) in response to BK in isolated human coronary microvessels.

METHODS AND RESULTS

Arterioles (97+/-4 micrometers; n=120) dissected from human right atrial appendages (n=78) were cannulated at a distending pressure of 60 mm Hg and zero flow. Changes in vessel diameter (video microscopy) and VSMC Em (glass microelectrodes) were measured simultaneously. In vessels constricted and depolarized (Em; -50+/-3 to -28+/-2 mV) with endothelin-1 (ET), dilation to BK was associated with greater membrane hyperpolarization (-48+/-3 mV at 10(-6) mol/L) than dilation to sodium nitroprusside (SNP) (-34+/-2 mV at 10(-4) mol/L) for similar degrees of dilation. Treatment with Nomega-nitro-L-arginine methyl ester (L-NAME; 10(-4) mol/L), an NO synthase inhibitor, partially decreased dilation to BK (maximum dilation 61+/-10% versus control 92+/-4%; P<0.05). Charybdotoxin (CTX; 10(-8) mol/L), a large-conductance Ca2+-activated K+ channel blocker, or apamin (10(-7) mol/L), a small-conductance Ca2+-activated K+ channel blocker, inhibited both dilation (CTX 22+/-6% and apamin 45+/-10% versus control 69+/-6%; P<0.05) and membrane hyperpolarization (CTX -31+/-2 mV and apamin -37+/-2 mV versus control -44+/-2 mV; P<0.05) to BK, whereas glibenclamide (10(-6) mol/L), an ATP-sensitive K+ channel blocker, was without effect.

CONCLUSIONS

Vasodilation of human coronary arterioles to BK is largely dependent on membrane hyperpolarization by Ca2+-activated K+ channel activation, with apparently less of a role for endothelium-derived NO. This suggests a role for K+ channel activation in regulating human coronary arteriolar tone.

Increased expression of vascular endothelial growth factor in human hepatocellular carcinoma

BACKGROUND/AIMS

Angiogenesis is critical for the development and progression of solid tumors. The purpose of this study was to evaluate the possible role of vascular endothelial growth factor (which is considered to be one of the most important factors involved in tumor-associated angiogenesis), in human hepatocellular carcinoma.

METHODS

Vascular endothelial growth factor gene and protein expression were analyzed by means of Northern hybridization and immunohistochemical methods in 5 hepatocellular carcinoma cell lines. Secretion of vascular endothelial growth factor was evaluated by immunoblotting of conditioned medium of these hepatocellular carcinoma cells. Further, we compared the level of vascular endothelial growth factor expression in hepatocellular carcinoma tissues along with that in surrounding tumor-free tissues obtained from 20 patients. We also analyzed mRNA expression of Flt-1, one of the vascular endothelial growth factor specific high-affinity receptors, in hepatocellular carcinoma cell lines.

RESULTS

Northern hybridization analysis and immunohistochemistry revealed that all cultured hepatocellular carcinoma cells exhibited a high level of vascular endothelial growth factor mRNA. In addition, vascular endothelial growth factor secretion by Hep G2, one of the hepatocellular carcinoma cell lines, was shown by Western blot. In vivo, we observed vascular endothelial growth factor expression in both hepatocellular carcinoma and non-hepatocellular carcinoma tissues. However, in 12 of 20 cases, vascular endothelial growth factor mRNA levels were significantly up-regulated in hepatocellular carcinoma tissues. In the majority of cases (10 out of 12 cases) with abundant tumor vascularity, vascular endothelial growth factor mRNA up-regulation in hepatocellular carcinoma tissues was observed. We failed to detect Flt-1 mRNA expression in hepatocellular carcinoma cells.

CONCLUSIONS

This study suggests that the possibility that hepatocellular carcinoma cells overexpress the vascular endothelial growth factor gene and protein. These findings support the hypothesis that vascular endothelial growth factor is one of the important factors involved in the angiogenesis of hepatocellular carcinoma, and may even be involved in the development and/or progression of hepatocellular carcinoma itself.

Simple genetic method to identify viridans group streptococci by colorimetric dot hybridization and fluorometric hybridization in microdilution wells

Simple dot hybridization and fluorometric hybridization methods in microdilution wells were designed and established for rapid and routine genetic identification of viridans group streptococci. Reference DNA extracted from each strain of 24 reference Streptococcus species was fixed both on a nitrocellulose filter and in a microdilution well. A 1-ml portion of the bacterial suspension which matched the turbidity of McFarland no. 2 standard was prepared when a streptococcal strain was isolated. It was lysed with achromopeptidase, and the DNA was quickly labeled with photobiotin under a sunlamp for 15 min. Dot hybridization and fluorometric hybridization were then carried out between the labeled DNA of the unknown organism and 24 unlabeled reference DNAs. Hybridized fragments on a nitrocellulose filter were detected by using alkaline-phosphatase-conjugated streptavidin and analyzed with a color graphic analyzer. Hybridized fragments in microdilution wells were quantitatively detected by using an enzyme, streptavidin-conjugated beta-D-galactosidase, and a fluorogenic substrate, 4-methylumbelliferyl-beta-D-galactoside. Strains belonging to each genetically distinct species could be identified by this dot blot hybridization test. However, some clinical strains cross-hybridized with two or more reference species, and then they were difficult to differentiate by dot blot hybridization. In such a case, fluorometric identification provided reliable results because the fluorometric method was more quantitative than dot blot identification. By these methods, it was possible to determine species assignment within the viridans group.

Human coronary arteriolar dilation to arachidonic acid depends on cytochrome P-450 monooxygenase and Ca2+-activated K+ channels

Endothelium-dependent hyperpolarization of vascular smooth muscle cells (VSMCs) plays a crucial role in regulating vascular tone, especially in resistance vessels. It has been proposed that metabolites of arachidonic acid (AA), formed by cytochrome P-450 monooxygenase (P450), are endothelium-derived hyperpolarizing factors (EDHFs). These metabolites have been reported to mediate dilation to endogenous vasoactive compounds, such as bradykinin and acetylcholine. However, it is not known whether these metabolites of AA contribute to dilation of human resistance vessels. This is important since it has been proposed that EDHF serves as a compensatory mechanism to maintain dilation in disease states. Therefore, we studied the effect of AA on vessel diameter and VSMC membrane potential in isolated human coronary microvessels. Arterioles (81+/-5 microm, n=70) were dissected from right atrial appendages at the time of cardiac surgery and cannulated at a distending pressure of 60 mm Hg and zero flow. Changes in internal diameter were recorded with videomicroscopy. Some vessels were impaled with glass microelectrodes to measure membrane potential of VSMCs while internal diameters were simultaneously recorded. After constriction (47+/-2%) with endothelin-1, AA (10(-10)to 10(-5)mol/L) induced substantial dilation of human coronary microvessels, which was abolished by removal of the endothelium. Treatment with 17-octadecynoic acid (17-ODYA, 10(-5) mol/L; a P450 inhibitor) attenuated maximal dilation to AA (49+/-9% versus 91+/-4% [control]; P<0.05 versus control), whereas indomethacin (INDO, 10(-5) mol/L; a cyclooxygenase inhibitor) and N omega-nitro-L-arginine methyl ester (L-NAME, 10(-4) mol/L; a NO synthase inhibitor) were without effect. Both 17-ODYA and miconazole (10(-5) mol/L, a chemically distinct P450 inhibitor) further reduced the dilation to AA in the presence of INDO. The presence of 40 mmol/L KCl or charybdotoxin (10(-8) mol/L, a blocker of large-conductance Ca2+-activated K+ channels) impaired dilation to AA (19+/-9% [KCI] versus 76+/-5% [control] and 47+/-6% [charybdotoxin] versus 91+/-3% [control]; P<0.05 for both). After depolarization with endothelin-1 (-26+/-1 mV from -48+/-3 mV [before endothelin]), AA (10(-5)mol/L) in the presence of INDO and L-NAME induced hyperpolarization of VSMCs (-57+/-5 mV). In the presence of 17-ODYA together with INDO and L-NAME, endothelin produced similar depolarization (-26+/-2 mV from - 48+/- 3 mV), but hyperpolarization to AA was reduced (-33+/-2 mV; P<0.05 versus absence of 17-ODYA). AA metabolites formed primarily by P450 produce potent endothelium-dependent dilation of human coronary arterioles via opening of Ca2+-activated K+ channels and hyperpolarization of VSMCs. These findings support an important role for P450 metabolites in the regulation of human coronary arteriolar tone.

Anatomic variations should be considered in total knee arthroplasty

The effect of anatomic variations on the operative techniques used in total knee arthroplasty (TKA) was assessed. In 133 Japanese patients with medial osteoarthritis (OA), six parameters were measured on anteroposterior radiographs of the lower extremities taken with the patients in the supine position. The results showed that the characteristics of the knees were bowing of the femoral shaft and proximal tibia vara, with lateral offset of the tibial shaft with respect to the center of the tibial plateau. The angle between a perpendicular to the mechanical axis and the tangent to the distal femoral condyles can be used in determining the external rotation of the femoral component. This angle was more than 3 degrees in 20% of the patients. The femoral component should therefore be externally rotated more than 3 degrees relative to the posterior condylar line in such patients. Because the center of the tibial plateau is located medial to the central line of the tibial shaft in knees with medial OA, the central point of the tibial articular surface should not be used for alignment of the tibial component. The medial offset stem of the tibial component may impinge against the medial wall. Anatomic variations should be evaluated before TKA is attempted.

Asymmetry of mediolateral laxity of the normal knee

BACKGROUND

Understanding the normal kinematics of the joints is important for reconstructive surgery. However, only a few extensive studies have been done on medial and lateral laxity of the normal knee.

METHODS

Radiographs of 50 normal knees were obtained under varus and valgus stress in both extension and flexion and the relative angle of the articular surface was measured.

RESULTS

In extension, the mean angle was 4.9 degrees in varus stress and 2.4 degrees in valgus stress. In flexion, the mean angle was 4.8 degrees in varus stress and 1.7 degrees in valgus stress. Lateral laxity was significantly greater than medial laxity in both extension and flexion.

CONCLUSIONS

Lateral laxity may be necessary for the medial pivot movement of the normal knee. There is some disagreement regarding the importance of pursuing the perfect rectangular gaps during total knee arthroplasty (TKA). The methods for measuring the tension of soft tissues during the operation are not accurate and do not always reflect the postoperative tensions of dynamic phases, such as walking and standing. Slight lateral laxity can be accepted with TKA, and further studies are necessary to determine whether prosthesis lift-off occurs in the replaced knee with slight lateral laxity similar to that in the normal knee.

Colonization of denture plaque by respiratory pathogens in dependent elderly

OBJECTIVES

Recently, there has been a resurgence of interest in the interactions between oral conditions and a number of prevalent systemic diseases. The morbidity and mortality of the dependent elderly that result from aspiration pneumonia have been recognized as a major geriatric health problem. The purpose of this study was to gain more information on the microflora of plaque on dentures and to assess the existence of oral infectious pathogens potentially causing the respiratory disease in the dependent elderly.

SUBJECTS AND METHODS

The denture bacterial flora of 50 dependent elderly were examined to identify microorganisms by the culture method.

RESULTS

18 species of microorganisms were detected in denture plaque in this study. A variety of pathogens with the potential to cause respiratory infection pathogens colonized on the dentures of dependent elderly.

CONCLUSION

The results of the present study revealed that bacteria that commonly cause respiratory infection colonized on the dentures of dependent elderly, suggesting that denture plaque may function as a reservoir of potential respiratory pathogens to facilitate colonization on the oropharynx.

Expression patterns of Brx1 (Rieg gene), Sonic hedgehog, Nkx2.2, Dlx1 and Arx during zona limitans intrathalamica and embryonic ventral lateral geniculate nuclear formation

The Brx1 homeobox gene has been isolated and shown to be expressed in the zona limitans intrathalamica (ZLI) of the mouse embryo. Brx1 is a member of the Brx gene family and comprises the genes for Brx1a and Brx1b, which differ in the sequence in the region located on the 5'-terminal side of the homeobox. The complete amino acid sequences of the open reading frame of Brx1a and Brx1b were determined and each was found to be similar to that of Rgs, the mouse homologue of the Rieger syndrome associated human RIEG gene (RGS), to the extent that the sequence of Rgs has been clarified. Brx1 was strongly expressed in the mammillary area as well as in the ZLI of the mouse embryonic brain. Homologues of Brx1a and Brx1b were isolated in chick in which the expression of Brx1 in the ventral diencephalon was well conserved. The expression of Brx1 along with that of Sonic hedgehog (Shh), Nkx2.2, Dlx1 and Arx was examined at the time of the formation of ZLI in mouse embryos. The expression of Shh was initially noted in the ventricular zone of the presumptive ZLI and was then replaced by that of Brx1 at the time of radial migration of the neuroepithelial cells. Nkx2.2 was widely expressed in the ventricular zone of presumptive ZLI and also as a narrow band in the mantle zone. The expression of Dlx1 and Arx in the presumptive ventral thalamus extended as far as ZLI and overlapped with that of Brx1. The Dlx1- and Arx-expressing cells in ZLI, which extended towards the lateral (pial) surface of the diencephalic wall, differed from those expressing Nkx2.2 and Brx1. The embryonic ventral lateral geniculate nucleus present in the visual pathway was eventually formed from these cells. Each homeobox gene was also expressed regionally in the nucleus, suggesting that the nucleus is comprised of subdivisions.

Anatomical analysis of the femoral condyle in normal and osteoarthritic knees

It is important to understand anatomical feature of the distal femoral condyle for treatment of osteoarthritic knees. Detailed measurement of the femoral condyle geometry, however, has not been available in osteoarthritic knees including valgus deformity. This study evaluated femoral condyle geometry in 30 normal knees, 30 osteoarthritic knees with varus deformity, and 30 osteoarthritic knees with valgus deformity using radiographs and magnetic resonance imaging (MRI). In radiographic analysis in the coronal plane, the femoral joint angle (lateral angle between the femoral anatomic axis and a tangent to femoral condyles) was 83.3 degrees in the normal knees, 83.8 degrees in the varus knees, and 80.7 degrees in the valgus knees. In MRI analysis in the axial plane, the posterior condylar tangent showed 6.4 degrees of internal rotation relative to the transepicondylar axis in the normal knees, 6.1 degrees in the varus knees, and 11.5 degrees in the valgus knees. These results suggested that there was no hypoplasia of the medial condyle in the varus knees, but the lateral condyle in the valgus knees was severely distorted. Surgeons should take this deformity of the lateral femoral condyle into account when total knee arthroplasty is performed for a valgus knee.

Can magnetic resonance imaging-derived bone models be used for accurate motion measurement with single-plane three-dimensional shape registration?

The purpose of this study was to compare three-dimensional (3D) kinematic measurements from single-plane radiographic projections using bone models created from magnetic resonance imaging (MRI) and computed tomography (CT). MRI is attractive because there is no ionizing radiation, but geometric field distortion and poor bone contrast degrade model fidelity compared to CT. We created knee bone models of three healthy volunteers from both MRI and CT and performed three quantitative comparisons. First, differences between MRI- and CT-derived bone model surfaces were measured. Second, shape matching motion measurements were done with bone models for X-ray image sequences of a squat activity. Third, synthetic X-ray images in known poses were created and shape matching was again performed. Differences in kinematic results were quantified in terms of root mean square (RMS) error. Mean differences between CT and MRI model surfaces for the femur and tibia were -0.08 mm and -0.14 mm, respectively. There were significant differences in three of six kinematic parameters comparing matching results from MRI-derived bone models and CT-derived bone models. RMS errors for tibiofemoral poses averaged 0.74 mm for sagittal translations, 2.0 mm for mediolateral translations, and 1.4 degrees for all rotations with MRI models. Average RMS errors were 0.53 mm for sagittal translations, 1.6 mm for mediolateral translations, and 0.54 degrees for all rotations with the CT models. Single-plane X-ray imaging with model-based shape matching provides kinematic measurements with sufficient accuracy to assess knee motions using either MRI- or CT-derived bone models. However, extra care should be taken when using MRI-derived bone models because model inaccuracies will affect the quality of the shape matching results.

Intact motility as a Salmonella typhi invasion-related factor

Invasiveness of Salmonella typhi was investigated. At first, we introduced Tn5 into the chromosome of a wild-type S. typhi strain, GIFU 10007, and screened the independent Tn5 insertion mutants for noninvasive (Inv-) strains. During the first half of this work, we obtained 4 Inv- strains from 1,338 independent Tn5 mutants. The four were either nonflagellate (Fla-), nonmotile (Mot-), or nonchemotactic (Che-). We then isolated more Fla-, Mot-, or Che- mutants and examined the invasiveness of these mutants. Sixty-three spontaneous or Tn5 insertion motility mutants, i.e., Fla-, Mot-, or Che-, were independently isolated from the wild-type strain GIFU 10007; all of them were noninvasive. Motile revertants isolated from some of these mutants showed the same invasiveness as the parent strain. P22-mediated transductional crosses were carried out between some of the motility mutants (as the recipients) and the Fla- reference strains of S. typhimurium with known deletion sites on the genome (as the donors). The mutational sites of the S. typhi mutants were assigned almost evenly to the three flagellar gene regions (regions I, II, and III) of S. typhimurium. The invasiveness of the motile recombinants obtained from the transduction assays was examined. The restoration of intact motility resulted in the restoration of invasiveness. Thus, we conclude that intact motility is an invasion-related factor of S. typhi. The relationship of Vi antigen to the invasiveness of S. typhi was also studied. Vi-negative mutants with intact motility remained invasive, whereas all 63 Inv- spontaneous or Tn5 mutants were Vi positive. Therefore, Vi antigen was not related to the invasiveness of S. typhi.