Durability of tungsten carbide burs for the fabrication of titanium crowns using dental CAD/CAM

The purpose of this study was to evaluate the durability of tungsten carbide burs for the fabrication of titanium crowns using two dental CAD/CAM systems (DECSY, Digital Process, Japan and Cadim, Advance, Japan). A tungsten carbide bur in each system was examined and used without fracture to fabricate 51 titanium crowns. For both systems tiny chips were found on the bur blade at the 11th machining. These chips gradually enlarged as the number of machining times increased. At the first machining no significant difference in the average surface roughness was found on the crown between the two systems (1.6 microm for DECSY and 1.2 microm for Cadim). The cutting grooves became dull and the average surface roughness increased as the number of machining times increased. It is concluded that the tungsten carbide burs for both systems can be used to fabricate up to 51 titanium crowns.     

Effects of sounds generated by a dental turbine and a stream on regional cerebral blood flow and cardiovascular responses

Effects of sound generated by a dental turbine and a small stream (murmur) and the effects of no sound (null, control) on heart rate, systolic and diastolic blood pressure, and hemodynamic changes (oxygenated, deoxygenated, and total hemoglobin concentrations) in the frontal cortex were measured in 18 young volunteers. Questionnaires completed by the volunteers were also evaluated. Near-infrared spectroscopy and the Finapres technique were employed to measure hemodynamic and vascular responses, respectively. The subjects assessed the murmur, null, and turbine sounds as pleasant, natural, and unpleasant, respectively. Blood pressures changed in response to the murmur, null, and turbine sound stimuli as expected: lower than the control level, unchanged, and higher than the control level, respectively. Mean blood pressure values tended to increase gradually over the recording time even during the null sound stimulation, possibly because of the recording environment. Oxygenated hemoglobin concentrations decreased drastically in response to the dental turbine sound, while deoxygenated hemoglobin concentrations remained unchanged and thus total hemoglobin concentrations decreased (due to the decreased oxygenated hemoglobin concentrations). Hemodynamic responses to the murmuring sound and the null sound were slight or unchanged, respectively. Surprisingly, heart rate measurements remained fairly stable in response to the stimulatory noises. In conclusion, we demonstrate here that sound generated by a dental turbine may affect cerebral blood flow and metabolism as well as autonomic responses.     

Transection of the innominate artery for tracheomalacia caused by persistent opisthotonus

Patients with cerebral palsy often develop opisthotonus. The trachea may be pinched between the innominate artery and the cervical spine. This compartmentalized thoracic inlet results in severe tracheomalacia. We successfully released tracheal compression by transection of the innominate artery. In case 1, a 4-year-old girl with cerebral palsy and opisthotonus was admitted due to respiratory distress. Bronchoscopy revealed severe tracheomalacia 2 cm above the carina. An endotracheal stent was placed through a tracheostomy. Two months later, she developed tracheal bleeding and bronchoscopy demonstrated a trachea-innominate artery fistula. Magnetic resonance brain angiography showed the presence of Willis circle, and transection of the innominate artery was justified. This was done through a low cervical skin incision. In case 2, a 6-year-old boy with cerebral palsy and opisthotonus had long-standing respiratory distress. Ventilatory support did not resolve the symptoms. The innominate artery was transected in the same fashion as in the first case. Case 1 has been free from respiratory distress for 4 months and case 2 for 3 years. Our experience suggests that the combination of tracheomalacia, opisthotonus causes severe respiratory distress. Transection of the innominate artery is a useful therapeutic strategy to release airway obstruction in this condition.     

Prevention of vocal fold scarring by topical injection of hepatocyte growth factor in a rabbit model

OBJECTIVES/HYPOTHESIS: Vocal fold scarring disrupts the layer structure of the vocal fold lamina propria that is essential for optimal mucosal vibration. Prevention of vocal fold scarring remains challenging. Hepatocyte growth factor (HGF) has strong antifibrotic activity. The authors' previous studies have found that HGF stimulates hyaluronic acid production and suppresses collagen production from vocal fold fibroblasts, suggesting that HGF has therapeutic potential in prevention of vocal fold scarring. The present study aimed to demonstrate the effects of HGF on vocal fold scarring in an in vivo rabbit model. STUDY DESIGN: Animal experiment. METHODS: The vocal fold mucosa was stripped unilaterally in 20 rabbits, then HGF or saline (sham-treated group) was immediately injected into the injured site. At 6 months after the procedure, histological, rheological, and physiological examinations of vibratory behavior were completed. RESULTS: Histological examination revealed excessive collagen deposition and disorganized elastin in the sham-treated group, whereas the HGF-treated group presented with better wound healing exhibiting less collagen deposition. Contraction of the injured vocal folds observed in the sham-treated group did not occur in the HGF-treated group. Rheological data indicated that the HGF-treated vocal folds were less stiff and viscous compared with the sham-treated group. Mucosal vibration of HGF-treated vocal folds appeared much better than the sham-treated group in terms of phonation threshold pressure, vocal efficiency, mucosal wave amplitude, and glottal closure. CONCLUSION: Hepatocyte growth factor proved to be useful in preventing vocal fold scarring and maintaining viscoelastic shear properties of the vocal fold.     

Analysis of limited fertility in intracytoplasmic sperm injection of sperm obtained by electroejactulation

Background and Aims :  We correlated findings in semen from patients with ejaculatory dysfunction with results of in vitro fertilization using their electroejaculated sperm.
Methods and Results :  Electroejaculation was carried out in six patients with the above-mentioned criteria for a total of eight times. Sperm was obtained in six attempts. Intracytoplasmic injection of these sperm was performed in 156 eggs. Sixty-seven eggs were fertilized; most of these were injected with motile sperm. Two women became pregnant, both after injection with motile sperm. As previously reported, electroejaculated sperm showed low motility and a low fertilization rate, but even motile sperm had a low fertilization rate.
Conclusion :  The results of the present study suggest the importance in fertilization of undetermined factors in addition to sperm motility. (Reprod Med Biol 2004; 3 : 9–12)     

Rehabilitation professionals' satisfaction with continuing education delivered at a distance using different technologies

This paper examines learner satisfaction with technologies used for distance delivery of continuing education across 10 Canadian sites: nine within the province of Alberta and one in Nunavut Territory. The technologies were satellite (or videotapes of) broadcasts, videoconferencing, and web-based technology. Learner satisfaction was evaluated using questionnaires. A survey on general issues related to continuing education was developed and mailed to random samples of health professionals and a convenience sample of stakeholders. The learners (n = 1,141) represented 20 types of health service providers who had attended at least one session delivered via satellite, videotape, or videoconferencing. Seven individuals completed the web-based course. Overall, the majority of participants were satisfied or very satisfied. In general, satellite delivery was received more favorably compared with videotapes of the same content. A total of 350 (33% response rate) health professionals and 37 (50% response rate) stakeholders returned the surveys. Nearly 50% of health professionals thought that clinical case presentations (rounds) were valuable to them, but over half of the stakeholders perceived that videotapes, rounds, and research seminars were valuable to health professionals. Ratings for the web-based course varied, indicating different learner characteristics. We conclude that it is possible to utilize multiple technologies to meet the continuing education needs of an interdisciplinary group of health service providers, but future research is needed to develop a framework for evaluating the usability of multiple existing and emerging technologies for distance education.     

Analysis of two types of novel alleles in the DXS10011 locus

A population study of the short tandem repeat locus DXS10011 was carried out in a sample of 104 unrelated Japanese individuals (56 males, 48 females). Thirty-six different alleles were distinguished. The power of discrimination was 0.933 (male) and 0.997 (female). Sequence analysis of alleles was examined for 34 samples. The sequence structures of the alleles were classified into three types: A, B and C. Type A had a regular repeat structure of the repeat region: (GAAA)(n). Types A and B differed in the base sequence of the repeat region. As an A (adenine) insertion in 5' upstream of (GAAA)(n) repeat unit was type C, this type was differentiated from type A.     

TNP-470, an angiogenesis inhibitor, suppresses the progression of peritoneal fibrosis in mouse experimental model

BACKGROUND: In patients on long-term peritoneal dialysis (PD), angiogenesis and vasculopathy are observed in the peritoneum, and the degree of vascularization correlates with the area of fibrotic tissue, suggesting the involvement of angiogenesis in the progression of peritoneal fibrosis. The aim of the present study was to evaluate the effect of TNP-470, an anti-angiogenic compound, on the development of peritoneal fibrosis induced by chlorhexidine gluconate (CG). METHODS: Peritoneal fibrosis was induced by injection of CG into peritoneal cavity of Institute for Cancer Research (ICR) mice. TNP-470 was injected subcutaneously with CG. Mice were sacrificed, and peritoneal tissues were dissected out at days eight and 16 after CG and TNP-470 injection. The expression patterns of CD31 (as a marker of endothelial cells), vascular endothelial cell growth factor (VEGF), alpha-smooth muscle actin (as a marker of myofibroblasts), heat shock protein 47 (HSP47), type III collagen, F4/80 (as a marker of mice macrophages), proliferating cell nuclear antigen (PCNA), and cyclin-dependent kinase 2 (Cdk2) were examined by immunohistochemistry. RESULTS: CG-injected mice showed thickening of the submesothelial zone and increased number of vessels, myofibroblasts, and infiltrating macrophages. The expression levels of VEGF, type III collagen, and HSP47 were increased, and a large number of PCNA-positive cells and Cdk2-expressing cells were observed in the thickened submesothelial area. Treatment with TNP-470 suppressed the submesothelial zone thickening and reduced collagen III expression as well as angiogenesis. TNP-470 also decreased the number of VEGF-expressing cells, myofibroblasts, macrophages, PCNA-positive cells, and Cdk2-expressing cells. CONCLUSION: Our results indicate the involvement of angiogenesis in the progression of peritoneal fibrosis, and suggest that TNP-470 may be potentially useful for the prevention of peritoneal fibrosis through inhibition of angiogenesis and suppression of myofibroblast proliferation.     

Development of cultivated mucosal epithelial sheet transplantation for ocular surface reconstruction

Regenerative medicine via tissue engineering is a newly developed medical field based on the use of somatic stem cells to generate biological substitutes and improve tissue functions. The achievement of these objectives depends on two important factors: stem cells, which are high in proliferability and differentiability, and the substrates that support them. In order to reconstruct the ocular surface in patients with severe ocular surface diseases, we decided to investigate the feasibility of human amniotic membrane as an epithelial carrier, and found that denuded amniotic membrane was the most appropriate substrate for this purpose. To develop the surgical treatment using denuded amniotic membrane as a carrier, we established the tissue engineering system for making transplantable epithelial sheets of either corneal or oral mucosal epithelial cells for ocular surface reconstruction.     

Evaluation of brain tumors by simultaneous dual isotope SPECT with 201Tl-chloride and 99mTc-MIBI

Single photon emission computed tomography (SPECT) is useful for detecting brain tumors. In this study, we evaluated the utility of simultaneous dual SPECT with 201Tl-Chloride (Tl) and 99mTc-MIBI (MIBI) for diagnosis of brain tumors. We evaluated 20 cases, including 2 glioblastomas, 7 anaplastic astrocytomas, 2 oligodendrogliomas, 2 anaplastic ependymomas, 2 medulloblastomas, 2 meningiomas, 1 malignant meningioma, 1 pituitary adenoma, and 1 craniopharyngioma. We analyzed the uptake ratio (T/N ratio) of tracers in both Tl and MIBI at max counts/pixels ratio in the region of interest. The T/N ratios in early and delayed images were described as early ratios (ER) and delay ratios (DR), respectively. The retention index (RI) was calculated as the DR/ER ratio. Significant correlations were found between ER and DR for both Tl (DR = 0.797 * ER + 0.359, r = 0.871), and MIBI (DR = 0.961 * ER - 0.191, r = 0.784). Next, we analyzed the correlations between Tl and MIBI SPECT, for ER, DR, and RI. ER values for the two were strongly correlated (r = 0.791), DR values were weakly correlated (r = 0.556), and RI exhibited no correlation between them (r = 0.328). There were no correlations between tumor volume and T/N ratio for the two (ER-Tl; r = 0.0095, DR-TI; r = 0.0050, ER-MIBI; r = 0.036, DR-MIBI; r = 0.254). Lastly no correlation was found between RI-Tl and RI-MIBI (r = 0.328). We discuss the difference in the mechanism of accumulation of two tracers and the significance of simultaneous dual SPECT using them for the differential diagnosis of pituitary tumors, regrowth of oligodendrogliomas, and multidrug resistance of chemotherapy. Dual SPECT with Tl and MIBI appears to be useful for the diagnosis of brain tumor.