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Y Arai

Publications and source records attributed to Y Arai.

At least 91 records · Page 5Linked to original sources
PubMed2001

Clinical application of a new compact CT system to assess 3-D images for the preoperative treatment planning of implants in the posterior mandible A case report.

When treatment planning before placing dental implants in the posterior region of the mandible, the locations of the inferior alveolar nerve and mental foramen need to be ascertained, as they determine the bone height available and the implant length selected. The purpose of this study was to introduce the clinical application of a newly developed compact computed tomography system (Ortho-CT) to assess three-dimensional (3-D) images for the preoperative treatment planning of implants in the posterior region of the mandible. To evaluate the 3-D images, we scanned using the Ortho-CT system the mandible with a radiopaque template placed in the posterior region. The Ortho-CT images provided excellent information for evaluating the morphology of the mandible, and for showing the location of the inferior alveolar nerve, mental foramen and the relationship of the template to the bone. We consider that Ortho-CT is a useful aid to preoperative treatment planning of implant therapy in the mandible.

Contrast Media↗
PubMed2001

Multiple-site optical recording reveals embryonic organization of synaptic networks in the chick spinal cord.

We examined embryonic expression of postsynaptic potentials in stages 26-31 (E5 to E7) chick spinal cord slices. Slow optical signals related to the postsynaptic potentials which were evoked by electrical stimulation of afferent fibers were identified in the dorsal grey matter and the ventral motoneuronal area. In cervical spinal cord (C13) preparations, the dorsal slow signal appeared from stage 28 (E6), whilst the ventral slow signal was recognized from stage 29. At stages 26 and 27 (E5), no slow signal was observed in either the dorsal or ventral regions. On the other hand, in lumbosacral spinal cord (LS5) preparations, the dorsal, as well as ventral, slow signals appeared from stage 29; at stage 28 no slow signal was detected in the dorsal or ventral regions. These results suggest that there are differences in the ontogenetic expression of synaptic functions between the dorsal and ventral regions, and between the cervical and lumbosacral spinal cords. In embryos older than stage 29, removal of Mg2+ from the bathing solution markedly enhanced the amplitude and incidence of the ventral slow signal. In addition, in C13 preparations at stage 28, removal of Mg2+ elicited small slow signals in the ventral region in which no synaptic response was evoked in normal Ringer's solution. The slow signals induced in the Mg2+-free solution were blocked by 2-amino-5-phosphonovaleric acid (APV), showing that they are attributable to N-methyl- D-aspartate (NMDA) receptors. These results suggest that functional synaptic connections via polysynaptic pathways are already generated on motoneurons, but are suppressed by a Mg2+ block on the NMDA receptors at developmental stages when synaptic transmission from the primary afferents to the dorsal interneurons is initially expressed in the dorsal region.

Animals↗
PubMed2001

Optical imaging of spreading depolarization waves triggered by spinal nerve stimulation in the chick embryo: possible mechanisms for large-scale coactivation of the central nervous system.

Using a multiple-site optical recording technique with a voltage-sensitive dye, we found that widely spreading depolarization waves were evoked by dorsal root stimulation in embryonic chick spinal cords. Spatiotemporal maps of the depolarization waves showed that the signals were mainly distributed in the ventral half of the slice, with the highest activity in the ventrolateral area. The propagation velocity of the waves was estimated to be in the order of mm/s. Depolarization waves were evoked in the ventral root-cut preparation, but not in the dorsal root-cut preparation, suggesting that the wave was triggered by synaptic inputs from the primary afferents, and that activation of the motoneurons was not essential for wave generation. In intact spinal cord-brain preparations, the depolarization wave propagated rostrally and caudally for a distance of several spinal segments in normal Ringer's solution. In a Mg(2+)-free solution, the amplitude and extent of the signals were markedly enhanced, and the depolarization wave triggered in the cervical spinal cord propagated to the brainstem and the cerebellum. The depolarization wave demonstrated here had many similarities with the vagus nerve-evoked depolarization wave reported previously. The results suggest that functional cell-to-cell communication systems mediated by the depolarization wave are widely generated in the embryonic central nervous system, and could play a role in large-scale coactivation of the neurons in the spinal cord and brain.

Animals↗
PubMed2001

Functional-rhythmical coupling of head and mandibular movements.

It is known that small head movements accompany the movements of the jaw during mastication; however, it is unknown whether these movements occur rhythmically and synchronously. The objective of this study was to determine whether there exists a functional coupling between the head and mandibular movements. Four healthy male adults (mean age 25.5) with normal occlusion and without TMD history were selected as subjects. Using the Trimet system, we measured tridimensionally both the movement of the head and the mandible by tracking upper and lower incisal points, respectively, during tapping movements with different opening range and frequency, then analysed the vertical component of these movements. The upper incisal point moved in opposite direction to the mandible in all tapping strokes in all subjects, during opening the head moved in a cranial direction and during closing in a caudal direction; the incidence rate for this concomitant movement was 98%, implying that the head moves periodically and rhythmically, as the mandible does. The cycle time of these coincident movements showed a correlation coefficient of 0.94. Moreover, the vertical range of head movement was within 10% of the jaw's movement. From these results we concluded that, at least during teeth tapping, the head moves in rhythmical coordination with mandibular movement.

Adult↗
PubMed2001

An autopsy case of the schizophrenic 32 years after lobotomy.

An autopsy case is reported here of a 69-year-old patient with schizophrenia, who was known retrospectively to have had a prefrontal lobotomy 32 years previously. The patient was diagnosed as schizophrenic at the age of 24 and the lobotomy was undertaken 13 years later. The patient was recently found outside in a dehydrated condition and admitted to a general hospital, where he died of respiratory failure. Bilateral cystic lesions were found in the deep white matter of the frontal lobe. The cyst walls consisted of glial fibrous tissues, and severe demyelination with axonal destruction was diffusely observed in the white matter of the frontal lobe. In the thinner frontal cortex without arcuate fibers (U fibers) close to the cavities, cytoarchitectural abnormalities were observed. In the thalamic nuclei marked retrograde degeneration and astrocytic gliosis were observed. The detailed neuropathological findings of a lobotomized schizophrenic brain are reported here. It is proposed that one should be reminded of a lobotomized brain if bilateral cysts are found.

Aged↗
PubMed2001

Caregiver depression predicts early discontinuation of care for disabled elderly at home.

This longitudinal study investigates the caregiving experiences among Japanese caregivers who provided informal care at home for disabled elderly between 1998 and 1999. Forty-seven caregivers of the impaired elderly continued caregiving at home in Matsuyama Town, a rural area of northern Japan, while 18 caregivers discontinued it. The mean score of the Center for Epidemiologic Studies Depression Scale in 1998 among those who gave up caregiving was significantly higher than that of those who continued caregiving, indicating that depression predicts early discontinuation of care in the home. This is one of the few studies in Japan to suggest that initial caregiver depression is a factor in the decision to terminate care for the disabled elderly at home.

Activities of Daily Living↗
PubMed2001

Acute normovolemic hemodilution for radical prostatectomy: can it replace preoperative autologous blood transfusion?

BACKGROUND: Although preoperative autologous blood donation (PAD) is accepted as a standard of care for radical prostatectomy, it is costly, time-consuming and has risks associated with blood storage. Acute normovolemic hemodilution (ANH) is reported to be less expensive and to preserve blood components more effectively than PAD. In the present study, the efficacy and safety of these two autologous blood-collection techniques were compared. METHODS: The study included 16 consecutive patients scheduled for radical prostatectomy. The first eight patients underwent conventional preoperative autologous blood donation of 400 mL 1 week before the operation (PAD group) and the second eight patients underwent acute normovolemic hemodilution followed by immediate operation (ANH group). All blood collected was transfused in the perioperative period. Preoperative and postoperative hematocrit levels in these two groups were compared. RESULTS: There were no differences in preoperative hematocrit, time of operation or operative blood loss between the two groups. In the ANH group, 1080 +/- 160 mL of blood were collected. The postoperative hematocrit level did not differ significantly between the groups. No patient in either group received allogeneic blood transfusion or experienced an adverse event directly related to blood transfusion. CONCLUSION: The two blood-conservation strategies resulted in similar postoperative hematologic outcomes. Given its advantages, which include lower cost, lower risk and higher convenience, ANH is one of the procedures that may replace conventional PAD for use in radical prostatectomy.

Aged↗
PubMed2001

Treatment outcome by risk group after radical prostatectomy in Japanese men.

BACKGROUND: North American investigators have suggested the usefulness of risk-group stratification based on prostate-specific antigen (PSA), clinical stage and biopsy Gleason score for predicting the biochemical outcome of prostate cancer after radical prostatectomy. There have been no reports of the application of this stratification to early biochemical outcome after radical surgery in Japanese men. METHODS: The study population consisted of 178 men treated with radical retropubic prostatectomy and bilateral pelvic lymph node dissection at Kitasato University Hospital (n = 110) and Kurashiki Central Hospital (n = 68) between October 1992 and May 1999. Pathologic and biochemical outcomes after radical prostatectomy were analyzed based on risk-group stratification. Risk groups were further analyzed according to detailed pathologic findings at biopsy. RESULTS: The median follow-up period for the 178 patients after radical surgery was 41.5 months (range, 2.0--82.0 months; mean, 40.9 months). Fifty-eight patients experienced PSA failure at a median of 8.0 months following surgery (range, 0.0--58.0). Risk-group stratification distinctly defined groups of pathologic findings in the radical prostatectomy specimens. The proportion of patients with PSA failure for low, intermediate and high-risk groups were 9.5%, 23.9% and 56.9%, respectively (P < 0.0001). Use of the number of cores with cancer and maximum cancer length in biopsy cores failed to improve risk stratification for PSA outcome in all risk groups. CONCLUSIONS: Risk-group stratification based on preoperative variables may significantly improve a physician's ability to counsel patients about PSA outcome after radical prostatectomy. Further improvement in risk stratification may call for use of variables other than the pathologic information in biopsy cores.

Aged↗
PubMed2001

Radical prostatectomy: time trends, morbidity and quality of life.

In recent years, increased screening for prostate cancer, primarily with prostate-specific antigen testing, has led to an apparent increase in the incidence of prostate cancer and resulted in a shift to an earlier patient age and tumor stage at diagnosis. From the early 1980s, there have been great advances in surgical technique. In the 1990s, radical prostatectomy gained popularity among Japanese urologists. Time trends and morbidity of contemporary anatomical radical prostatectomy in Japan are reported here. In addition, the quality of life in men undergoing radical prostatectomy is discussed.

Humans↗
PubMed2001

The role of volume-weighted mean nuclear volume in predicting tumour biology and clinical behaviour in patients with prostate cancer undergoing watchful waiting.

OBJECTIVE: To investigate whether the volume-weighted mean nuclear volume (MNV, the only means by which unbiased estimates of three-dimensional variables can be obtained from a two-dimensional section by stereological methods) at diagnosis correlates with tumour biology and clinical behaviour in patients with prostate cancer treated by watchful waiting. PATIENTS AND METHODS: In a prognostic study, 64 patients with clinically localized prostate cancer were followed prospectively with initial expectant management. The median (mean, range) follow-up was 22 (27, 6.0-68) months. The prostate specific antigen (PSA) doubling time (PSADT) was calculated by linear regression. The MNV was estimated using biopsy specimens, based on a stereological method, and compared with PSADT and traditional clinicopathological variables. RESULTS: PSADT was significantly associated with MNV, but not with other clinicopathological variables. The PSA 'rapid-riser' subset (PSADT or=median value) and PSA-stable subsets (P = 0.0017 and 0.004, respectively). On multivariate analysis using a stepwise Cox proportional hazards regression, only MNV remained independently significant as a predictor of clinical progression among the clinicopathological variables (P < 0.001). CONCLUSIONS: These findings suggest that cancer cell nuclear volume is significantly associated with tumour biology and behaviour in patients with prostate cancer. Although further study with a larger patient population is needed to confirm the findings, estimates of MNV may be an important prognostic indicator in men treated with watchful waiting.

Age of Onset↗
PubMed2001

Intrarenal bacillus Calmette-Guérin therapy for carcinoma in situ of the upper urinary tract: long-term follow-up and natural course in cases of failure.

OBJECTIVE: To assess the long-term efficacy of intrarenal bacillus Calmette-Guérin (BCG) therapy for the treatment of cytologically diagnosed upper tract carcinoma in situ (CIS) and report the time course in cases of failure. PATIENTS AND METHODS: Fourteen renal units in 11 patients cytologically diagnosed as having upper urinary tract (UUT) CIS were treated with intrarenal BCG instillation. The BCG solution was administered by retrograde ureteric catheterization weekly for 6 weeks. RESULTS: Seven units were radiologically and cytologically free of disease at a median follow-up of 60 months. Two units which showed an initial response had recurrence with ipsilateral UUT CIS. The remaining five units did not respond to BCG. Of seven units with an initial negative response or recurrent UUT CIS, nephroureterectomy was undertaken in one because of coincidental renal cell carcinoma. In four of the remaining six units, invasive pelvic tumour developed at a mean follow-up of 20.5 months after the final instillation. Computed tomography showed wall thickening of the renal pelvis in two and mass-forming tumour in the renal parenchyma mimicking renal cell carcinoma in two. In three of these four cases, retrograde pyelography did not show typical findings of renal pelvic tumour, e.g. filling defect, infundibular obstruction or stenosis. CONCLUSIONS: Intrarenal BCG is effective in the treatment of UUT CIS in a long-term follow-up. In cases with a poor response or ipsilateral recurrence of CIS, there is a high risk of developing invasive tumour. Close follow-up using computed tomography is recommended because of the atypical radiographic findings of such tumours.

Adjuvants, Immunologic↗
PubMed2001

Lipoprotein metabolism in Japanese centenarians: effects of apolipoprotein E polymorphism and nutritional status.

OBJECTIVES: To assess the complex interaction of apolipoprotein (apo) E polymorphisms and environmental factors on lipoprotein profile in centenarians. DESIGN: Cross-sectional analysis. SETTING: Tokyo metropolitan area. PARTICIPANTS: Seventy-five centenarians and 73 healthy older volunteers (mean age 63.1 +/- 10.0) living in the Tokyo metropolitan area. MEASUREMENTS: Plasma lipids and lipoproteins, cholesteryl ester transfer protein mass, apo E phenotype, body mass index, nutritional indices (serum albumin, prealbumin, transferrin), dietary intake, inflammation markers (C-reactive protein (CRP), interleukin-6 (IL-6)), activities of daily living, and cognitive function. RESULTS: In comparison with older people, the centenarians had low concentrations of total and low-density lipoprotein cholesterol (LDL-C) and a relative predominance of high-density lipoprotein 2 cholesterol. No environmental factor, except the number of apo E epsilon2 alleles, was a significant determinant of LDL-C and apo B, suggesting that the low apo B-containing lipoprotein in centenarians may be attributable to a genetic cause. Centenarians had elevated levels of lipoprotein (a) and decreased high-density lipoprotein cholesterol (HDL-C), which seem to be an unfavorable lipoprotein profile. Lower levels of HDL-C in the centenarians were associated with decreased serum albumin, elevated CRP and IL-6 levels, and cognitive impairment, suggesting that HDL-C could be a sensitive marker for frailty and comorbidity in the oldest old. CONCLUSIONS: Low levels of apo B-containing lipoproteins attributable to a genetic cause may be advantageous for longevity. Lipoprotein profiles in centenarians were consistently related to the subjects' nutritional status, inflammation markers, and apo E polymorphisms. The results provide evidence for the importance of maintaining nutritional status in the very old.

Activities of Daily Living↗
PubMed2001

Pre-operative detection of malignant hepatic tumours: value of combined helical CT during arterial portography and biphasic CT during hepatic arteriography.

AIMS: The purpose of our study was to evaluate the observer performance with combined helical CT during arterial portography (CTAP) and biphasic CT hepatic arteriography (CTHA) in the pre-operative detection of malignant hepatic tumours. METHODS: Computed tomography images obtained in 41 patients with suspected hepatic tumours were retrospectively reviewed. In a blind fashion, three off-site, independent radiologists reviewed CTAP and early-phase CTHA combined for the first review, then late-phase CTHA was added for the second review. Statistical analysis was conducted on lesion-by-lesion and segment-by-segment bases; a total of 328 liver segments including 65 segments with 74 malignant hepatic tumours ranging in size from 5 to 100 mm (mean, 21.4 mm) were analysed. RESULTS: Sensitivity for detection of liver segments harbouring tumours of CTAP and biphasic CTHA combined (82%) was identical to that of CTAP and early-phase CTHA combined (82%). Specificity of CTAP and biphasic CTHA combined (93%) was greater than that of CTAP and early-phase CTHA combined (90%, P < 0.005). The mean confidence level for the 74 tumours significantly increased by adding late-phase CTHA (P < 0.0005). The mean confidence level for 100-142 benign perfusion abnormalities detected with CTAP and early-phase CTHA combined significantly decreased by adding late-phase CTHA (P < 0.0005). CONCLUSION: By combining late-phase CTHA with CTAP and early-phase CTHA information, the specificity for the detection of malignant hepatic tumours rises significantly, allowing more accurate preoperative tumour detection.

Aged↗
PubMed2001

Clinical study of venous thromboembolism during pregnancy and puerperium.

We encountered 16 cases of venous thromboembolism (VTE) in women during pregnancy and/or puerperium over the past 15 years at our perinatal center, representing 0.14% of all patients who delivered babies. The present study was undertaken to analyze the risk factors, clinical course and outcomes in these 16 cases. The ages of the patients varied from 29 to 39 years. Four women had pulmonary embolism (PE), 3 of which after caesarean section (C/S) at 35 to 40 weeks, and one case after ovarian cystectomy at 13 weeks of gestation. Twelve cases had deep venous thrombosis (DVT), 4 of which during pregnancy, and the remaining 8 cases after C/S. Four patients who had DVT during a normal course of pregnancy had severe thrombophilia: antiphospholipid antibody syndrome, a history of thrombosis and antithrombin (AT) deficiency. They were treated with heparin with or without AT and had healthy babies via successful vaginal deliveries. The common risk factors in 3 cases of PE with C/S was prolonged bed rest due to threatened premature delivery with total placenta previa, uterine myoma and Ehlers-Danlos syndrome. Other risk factors were massive bleeding, and positive lupus anticoagulant. However, the case of the ovarian cystectomy had only one risk factor, which was obesity. This patient died but the remaining patients recovered with treatment. Because of the low incidence of thrombosis in the Japanese population, prophylactic anticoagulant therapy has not routinely been given to patients undergoing obstetrical operations. However, proper management including prophylactic anticoagulant therapy might be considered for risk patients, depending on the risk factors.

Adult↗
PubMed2001

Ortho cubic super-high resolution computed tomography: a new radiographic technique with application to the temporomandibular joint.

OBJECTIVE: The purpose of this study was to present a newly developed ortho cubic super-high resolution computerized radiographic technique (Ortho-CT) and its application to the temporomandibular joint. METHOD AND PATIENTS: A prototype was assembled on a Scanora (Soredex Findent Co) with the use of a 4-inch image intensifier instead of film. Data were collected from a single 360 degrees scan and a cylinder 32 mm in height and 38 mm in diameter. Images were reconstructed with a software program on a personal computer. Imaging data consisted of 240 (height) x 280 (diameter) cubic voxels, each with a dimension of 0.136 mm. With this small voxel size, the image resolution was high and was the same in any direction. Three patients with temporomandibular joint disease (trauma, pain and dysfunction, fibroosseous ankylosis) were evaluated with Ortho-CT, and the images were compared to routine radiographic films. CONCLUSION: Preliminary clinical experience with Ortho-CT demonstrates subjectively superior image quality compared to panoramic and conventional tomographic images. The images were similar to conventional computed tomography, but this new radiographic technique is less expensive, takes less space, and gives a lesser patient dose.

Adult↗
PubMed2001

Cementless Lord total hip arthroplasty: cup loosening common after minimum 10-year follow-up of 103 hips.

We evaluated the clinical and radiographic results of 103 (88 patients) cementless Lord total hip arthroplasty after a mean follow-up period of 12.5 (10-16) years. 77 hips had arthrosis, 15 rheumatoid arthritis and 11 osteonecrosis. The preoperative mean Harris Hip Score improved from 47 (19-66) to 87 (62-99) at 5 years, but declined to 77 (56-97) at the final examination. The survivorship of the cup, using radiographically confirmed aseptic loosening as the end point, was 63% at 10 years and 45% at 15 years and the survivorship of the stem was 97% at 10 years and 96% at 15 years. The low figures of the cup may be due to insufficient contact between the smooth-surfaced threads of the cup and the acetabular bone. Thinner polyethylene, insufficient initial bone coverage, and larger femoral head diameter were significantly related to the occurrence of loosening. We can not recommend this smooth-surfaced threaded cup because of its high failure.

Adult↗
PubMed2001

Enhancement of hyperthermia-induced apoptosis by a free radical initiator, 2,2'-azobis (2-amidinopropane) dihydrochloride, in human histiocytic lymphoma U937 cells.

To elucidate the mechanism how a free radical initiator, 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH), induces cell death at hyperthermic temperatures, apoptosis in a human histiocytic lymphoma cell line, U937, was investigated. Free radical formation deriving from the thermal decomposition of AAPH was examined by spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). An assay for DNA fragmentation, observation of nuclear morphological changes, and flow cytometry for phosphatidylserine (PS) externalization were used to detect apoptosis and revealed enhancement of 44.0 degrees C hyperthermia-induced apoptosis by free radicals due to AAPH. However, free radicals alone derived from AAPH did not induce apoptosis. Hyperthermia induced the production of lipid peroxidation (LPO), an increase in intracellular Ca2+ concentration ([Ca2+]i) and enhanced expression of the type 1 inositol 1,4,5-trisphosphate receptor (IP3R1). The effects of hyperthermia on LPO and [Ca2+]i were enhanced markedly by the combination with AAPH. A significant decrease in Bcl-2 expression, increase in Bax expression, a loss of mitochondrial membrane potential (delta psi m) and a marked increase in cytochrome c expression were found only in cells treated with hyperthermia and AAPH. Although an intracellular Ca2+ ion chelator, BAPTA-AM, completely inhibited DNA fragmentation, water-soluble vitamin E, Trolox, only partially suppressed DNA fragmentation and the increase in [Ca2+]i. In contrast, LPO was inhibited completely by Trolox, but no inhibition by BAPTA-AM was found. These results suggest that apoptosis induced by hyperthermia alone is due to the increase in [Ca2+]i arising from increased expression of IP3R1 and LPO. Additional increase in [Ca2+]i due to increased LPO and the activation of mitochondria-caspase dependent pathway play a major role in the enhancement of apoptosis by the combination with hyperthermia and AAPH.

Amidines↗