Biomedical subjects

J Takahashi

Publications and source records attributed to J Takahashi.

At least 19 recordsLinked to original sources

PubMed2006

Choroidal blood flow in the foveal region in eyes with rhegmatogenous retinal detachment and scleral buckling procedures.

AIMS: To investigate changes in choroidal blood flow (ChBF) in the foveal region of the human eye with rhegmatogenous retinal detachment induced by scleral buckling. METHODS: ChBF was measured in the foveal region using laser Doppler flowmetry in patients with a rhegmatogenous retinal detachment and no macular involvement before and after scleral buckling. The ChBF ratio was evaluated (ChBF of the affected eye to ChBF of the fellow control eye) to minimise individual variations. RESULTS: Retinal reattachment was confirmed by 2 weeks after scleral buckling in all patients. The ChBF in the foveal region of the affected eyes did not differ from the fellow eyes before scleral buckling. The ChBF ratio significantly (p<0.05) decreased 2 and 4 weeks after scleral buckling compared with that before scleral buckling and returned to baseline 12 weeks after scleral buckling. CONCLUSIONS: The results suggest that ChBF in the foveal region transiently decreases after scleral buckling and recovers to the baseline level within 12 weeks in patients with a retinal detachment and no macular involvement.

Adult↗

PubMed2006

Stem cell therapy for Parkinson's disease.

Transplantation of fetal dopaminergic (DA) neurons can produce symptomatic relief for patients with Parkinson's disease, but the technical and ethical difficulties have limited the application of this therapy. Neural precursor cells and embryonic stem cells (ESCs) are expected to be candidates of potential donor cells for transplantation. Human neural precursor cells obtained from the midbrain give rise to TH-positive neurons. The growth of the cells, however, is slow and the differentiation rate of DA neurons is still low for clinical application. Monkey ESCs give rise to midbrain DA neurons, and the transplanted ESC-derived neurospheres function as DA neurons, attenuating the neurological symptoms of the monkey Parkinson's disease model. These results suggest the possibility of using stem cells for the treatment of Parkinson's disease, but problems such as the low survival rate in vivo and tumor formation must be solved.

Animals↗

PubMed2006

An evaluation of polyvinylidene film dressing for treatment of pressure ulcers in older people.

OBJECTIVE: To compare the effectiveness of polyvinylidene (PVL) food wrap as a dressing material versus conventional ointments and gauze dressings for pressure ulcers in patients aged 60 years or over. METHODS: A prospective open controlled trial was conducted. The severity of pressure ulcers in both groups was evaluated using the DESIGN system. Scores were compared at baseline, four, eight and 12 weeks. RESULTS: Twenty-five patients were treated with the PVL film (test) dressings and 24 with the conventional treatment (control). The test group showed greater improvement in DESIGN scores than the control group throughout the observation period, and the difference reached statistical significance at 12 weeks (p < 0.05). The incidences of local wound infection in the two groups were not statistically different (p > 0.999). CONCLUSION: The PVL film dressing was more effective than conventional treatment in the management of severe pressure ulcers.

Aged↗

PubMed2006

A single base insertion of the 4-alpha-galactosyltransferase gene led to the deficiency of Gb3 biosynthesis.

cDNAs for alpha 1,4 galactosyltransferase (A4GALT) have been isolated. To explore the molecular basis of the p phenotype in Japanese donors, we analyzed the A4GALT gene sequences of normal and p phenotype samples. The coding region in the A4GALT gene for DNA sequencing was amplified by PCR amplification. A4GALT expression vectors for individual were constructed by PCR amplification of the coding region using primers and subsequent subcloning into an expression vector. The expression of Gb3/CD77 antigen on the cell surface was evaluated by flow cytometry and by immunochemical techniques. All individuals with the p phenotype were found to have a single base insertion (A4GALT/insC) at the same nucleotide position. Neither the transfectant cells with a mutant gene (A4GALT/insC) of donor origin or those with a synthesized mutant gene (A4GALT/insC-Mu) expressed Gb3 antigen indicating that the presence of A4GALT/insC diminished the A4GALT enzyme activity. In addition, an allele-specific PCR (ASP) system was developed in which of the p phenotype with A4GALT/insC can be unambiguously discriminated from normal donors. Based on the finding that a single base insertion (A4GALT/insC) diminishes A4GALT activity, an ASP assay was developed to detect individuals with this particular p phenotype.

Antigens, Tumor-Associated, Carbohydrate↗

PubMed2005

Synthetic biodegradable polymers as drug delivery systems for bone morphogenetic proteins.

Bone morphogenetic proteins (BMP) induce bone formation in vivo, and clinical application in repair of bone fractures and defects is expected. However, appropriate systems to deliver BMP for clinical use need to be developed. We synthesized a new synthetic biodegradable polymer, poly-D,L-lactic acid-para-dioxanone-polyethylene glycol block copolymer (PLA-DX-PEG), to serve as a biocompatible, biodegradable polymer for recombinant human (rh) BMP-2 delivery systems. In animal experiments, new bone was efficiently formed and a large bone defect was repaired using PLA-DX-PEG/rhBMP-2 composites. In addition, this new polymer could be used as an injectable delivery system for rhBMP-2. The rhBMP-2/PLA-DX-PEG composites also could be combined with other materials such as hydroxyapatite or titanium. This new synthetic polymer might be used for rhBMP-2 delivery in various clinical situations involving repair of bone, leading to great changes in orthopedic treatment.

Animals↗

PubMed2005

Effect of ruminal administration of Escherichia coli wild type or a genetically modified strain with enhanced high nitrite reductase activity on methane emission and nitrate toxicity in nitrate-infused sheep.

The effects of two kinds of Escherichia coli (E. coli) strain, wild-type E. coli W3110 and E. coli nir-Ptac, which has enhanced NO(2) reduction activity, on oral CH(4) emission and NO(3) toxicity in NO(3)-treated sheep were assessed in a respiratory hood system in a 4 x 6 Youden square design. NO(3) (1.3 g NaNO(3)/kg(0.75) body weight) and/or E. coli strains were delivered into the rumen through a fistula as a single dose 30 min after the morning meal. Escherichia coli cells were inoculated for sheep to provide an initial E. coli cell density of optical density at 660 nm of 2, which corresponded to 2 x 10(10) cells/ml. The six treatments consisted of saline, E. coli W3110, E. coli nir-Ptac, NO(3), NO(3) plus E. coli W3110, and NO(3) plus E. coli nir-Ptac. CH(4) emission from sheep was reduced by the inoculation of E. coli W3110 or E. coli nir-Ptac by 6 % and 12 %, respectively. NO(3) markedly inhibited CH(4) emission from sheep. Compared with sheep given NO(3) alone, the inoculation of E. coli W3110 to NO(3)-infused sheep lessened ruminal and plasma toxic NO(2) accumulation and blood methaemoglobin production, while keeping ruminal methanogenesis low. Ruminal and plasma toxic NO(2) accumulation and blood methaemoglobin production in sheep were unaffected by the inoculation of E. coli nir-Ptac. These results suggest that ruminal methanogenesis may be reduced by the inoculation of E. coli W3110 or E. coli nir-Ptac. The inoculation of E. coli W3110 may abate NO(3) toxicity when NO(3) is used to inhibit CH(4) emission from ruminants.

Animals↗

PubMed2005

Frequency of early and late-onset dementias in a Japanese memory disorders clinic.

The aim of this study was to compare the diagnostic profiles of patients with early (age<65 years) and late (age>or=65 years) onset of dementia in a memory disorders clinic in Japan. A total of 512 consecutive memory clinic patients were evaluated using clinical information and results of examinations. Diagnosis of dementia was made according to DSM-III-R, and that of subtypes according to standard diagnostic criteria. A total of 464 patients met the criteria for dementia. Amongst late-onset patients (n=430), Alzheimer's disease (AD) (48.1%) was the most frequent cause of dementia, followed by AD with cerebrovascular disease (CVD) (31.4%), vascular dementia (VaD) (9.1%), dementia with Lewy bodies (DLB) (3.7%), frontotemporal lobar degeneration (FTLD) (1.6%), and others (5.8%). On the contrary, amongst early onset patients (n=34), the most common dementia diagnosis was AD (38.2%), followed by VaD (23.5%), FTLD (14.7%), AD with CVD (5.9%), DLB (2.9%), and others (17.6%). FTLD and VaD were significantly more common in the early onset group. All patients, but one, with DLB and Parkinson's disease dementia were late-onset. The relative frequencies of AD, VaD, and DLB in our series are consistent with epidemiologic findings in several Western countries; however, the frequency of FTLD is not consistent with the previous findings presenting high frequency in late-onset patients in some Western countries.

Adenosine Triphosphatases↗

PubMed2005

Effect of Escherichia coli wild type or its derivative with high nitrite reductase activity on in vitro ruminal methanogenesis and nitrate/nitrite reduction.

The effects of two kinds of Escherichia coli strains, wild-type E. coli W3110 or E. coli nir-Ptac, which has enhanced nitrite reduction activity, on in vitro CH4 production and nitrate and nitrite reduction in cultures of mixed ruminal microorganisms was investigated using continuous incubation systems. Escherichia coli nir-Ptac, a derivative of wild-type E. coli W3110, was constructed by replacing self promoter of nir BD operon encoding subunits of nitrite reductase in E. coli W3110 by tac promoter to make the expression of nir BD higher and constitutive. The nitrite reductase activity of E. coli nir-Ptac was approximately twice as high as E. coli W3110. The culture media consisted of 400 mL of strained ruminal fluid taken from two nonlactating Holstein cows receiving a basal diet of orchardgrass hay at maintenance level (55 g of DM/kg of BW0.75 daily), and 400 mL of autoclaved artificial saliva. Treatments were arranged in two separate 3 x 3 factorials consisting of nitrate (NaNO3; 0, 5, or 10 mM) without E. coli or inoculated with E. coli W3110 or E. coli nir-Ptac, or nitrite (NaNO2; 0, 1 or 2 mM) without E. coli or inoculated with E. coli W3110 or E. coli nir-Ptac. The control culture contained no chemical or microbial additives. Escherichia coli cells were inoculated into in vitro mixed ruminal cultures at approximately 2 x 10(8) to 10(9) cells/mL. Methane production by ruminal microorganisms was decreased markedly (P < 0.001) by the addition of nitrate and nitrite, and by the inoculation of cultures with E. coli W3110 or E. coli nir-Ptac (P < 0.01). With mixed nitrite-containing cultures, E. coli nir-Ptac inhibited (P < 0.001) in vitro nitrite accumulation and CH4 production more than E. coli W3110, which may be due to the tac promoter-enhanced nitrite reductase activity of E. coli nir-Ptac accelerating electrons to be consumed for nitrite reduction rather than CH4 biosynthesis. In conclusion, anaerobic cultures of E. coli W3110 or E. coli nir-Ptac may decrease CH4 production in the rumen. The inoculation of E. coli W3110 or, especially, E. coli nir-Ptac to mixed ruminal microorganisms may decrease nitrite toxicity when ruminants consume high-nitrate-containing forages and when nitrite is applied to abate ruminal CH4 production.

Animals↗

PubMed2005

Effects of yeast culture and galacto-oligosaccharides on ruminal fermentation in holstein cows.

Four nonlactating, ruminally cannulated Holstein cows were used in a 4 x 4 Latin square design, balanced for residual effects, to evaluate the effects of supplementing dairy cow diets with yeast culture (Trichosporon sericeum; YC), galacto-oligosaccharides (GOS), or the mixture of YC and GOS on ruminal fermentation, microbial N supply, in situ degradation, and energy and nitrogen metabolism. Treatments were arranged in a 2 x 2 factorial as follows: 1) basal diet, 2) basal diet plus 10 g/d YC, 3) basal diet plus 2% GOS, 4) basal diet plus a mixture of 10 g/d YC and 2% GOS. Nitrogen losses in urine were lower, and retained N was higher, for cows supplemented with a mixture of YC and GOS. Ruminal pH was lower in cows supplemented with GOS alone compared with other treatments. Total VFA concentration was higher in cows fed control and GOS-supplemented diets than in those fed YC containing diets. The molar proportion of propionate was higher, and the molar proportion of acetate was lower, in cows fed control diets. Microbial N supply was higher in cows fed control diets. There were no major positive effects of supplements observed in this study. However, supplementation of a mixture of YC and GOS had a tendency for synergistic effects on N metabolism and in situ degradation of a soluble fraction of oat straw DM and CP of concentrates compared with supplementation of YC or GOS alone.

Animal Feed↗

PubMed2005

Clinical usefulness of CEA-mRNA determination in minor effusion.

Malignant pleural effusion of lung cancer is an important prognostic factor, even in minor effusions. Previous studies reported that cytological examination could not detect malignant cells in pleural dissemination cases. Therefore, we used real-time PCR as a more sensitive test to detect malignant cells. The subjects were selected from 132 primary lung cancer patients and 8 benign tumor patients as negative control. These subjects had no apparent pleural effusion or distant metastasis. All subjects were negative on cytological examination and without exfoliation evidence. The follow-up duration was 18.1 +/- 7.1 months (mean +/- SD). In the real-time PCR, the CEA-mRNA and GAPDH-mRNA parameters were measured simultaneously, and the CEA-mRNA ratio was obtained as normalized values of CEA-mRNA divided by GAPDH-mRNA. The CEA-mRNA ratio in our study was correlated with lymph node metastasis (N-factor: p = 0.0948) and lymphatic invasion (Ly-factor: p = 0.0520). Using a proportional hazard model, with recurrence or death as terminal point, the CEA-mRNA ratio affected the recurrence risk by 1.920 (95% CI: 1.104-3.340) in Stage 1a. Using log rank testing, we found significant differences in the recurrence rate between the CEA-mRNA-positive and -negative cases (p = 0.0039) at cut-off point 0.1.

Base Sequence↗

PubMed2004

Surgical treatment of seizures from the peri-Sylvian area by perinatal insult: a case report of ictal hypersalivation.

UNLABELLED: OBJECTIVES AND IMPORTANCE: It is important to evaluate the seizure manifestation of epilepsy before surgical planning. A patient with partial epilepsy manifesting hypersalivation who underwent resection of the epileptogenic foci with satisfactory postoperative seizure control is reported. CLINICAL PRESENTATION AND INTERVENTION: A 26-year-old man, with a history of perinatal asphyxia, started having medically intractable partial epilepsy at the age of 10 years. His seizure was characterized by throat discomfort followed by hypersalivation. Brain MRI showed an atrophic lesion around the peri-Sylvian area. Scalp recorded EEG did not demonstrate robust epileptiform activity localized enough to define the epileptogenic zone. The patient underwent invasive recording by multiple subdural electrode grids, which showed that the seizure arose from the left anterior frontal operculum. After resection of epileptogenic opercular cortex, the seizures disappeared with no additional neurological deficits. CONCLUSION: Although the responsible sites for ictal drooling are distributed in multiple areas including insula, medial temporal area and operculum, the seizure can be successfully controlled by focus resection of the frontal opercular area in a selected patient with careful presurgical evaluation.

Adult↗

PubMed2004

Hydroxyapatite particles as a controlled release carrier of protein.

This study examines the possibility of using hydroxyapatite (HAp) particles as a controlled release carrier of protein. In order to achieve effective protein release from HAp particles, it is necessary to regulate the conjugated amount of protein on HAp and the resorption of HAp. HAp particles were synthesized at different temperatures (40 degrees C, 60 degrees C, 80 degrees C) in wet condition and the physico-chemical properties of synthesized HAp particles were examined. HAp particles synthesized at low temperatures showed low crystallinity, high solubility and large specific surface area. The useful growth factors for bone regeneration, such as BMP, bFGF and TGF-beta, are basic proteins, so cytochrome c (pI=10.2) was used as a model protein and the adsorptive property of protein on HAp particles was investigated. The protein adsorption on HAp particles changed depending on its specific surface area and the chart of protein adsorption on HAp particles showed a typical Langmuir curve. These findings suggest that the adsorbed amount of protein on HAp particles could be regulated by HAp synthesizing temperature and the concentrations of protein solution. The release kinetics of protein from the HAp particles that adsorbed the protein (HAp-pro) was also evaluated in different pH solutions (pH 4.0 and 7.0). The released protein gradually increased time dependently when HAp-pro were immersed in pH 4.0 solution, but the released protein was significantly smaller when HAp-pro were immersed in pH 7.0 solution. Moreover, the release rate of protein from HAp-pro differed in each HAp that was synthesized at different temperatures, suggesting that the release of protein from HAp-pro depended on HAp resorption. These results suggest that HAp particles synthesized at different temperature are useful as a controlled release carrier of protein.

Adsorption↗

PubMed2004

Subregions of human MT complex revealed by comparative MEG and direct electrocorticographic recordings.

OBJECTIVE: To locate the visual motion complex (MT+) and study its response properties in an epilepsy surgery patient. METHODS: A 17-year-old epilepsy patient underwent invasive monitoring with subdural electrodes in the right temporo-parieto-occipital area. MT+ was investigated by cortical electric stimulation and by epicortical visual evoked potentials time-locked to motion onset of sinusoidal gratings (motion VEP). Motion-related visual evoked magnetic field (motion VEF) was also recorded before the electrode implantation to complement the invasive recording. RESULTS: Motion VEPs revealed two subregions within MT+, generating early and late potentials respectively. The early activity with a peak around 130 ms was localized at a single electrode situated immediately caudal to the initial portion of the ascending limb of the superior temporal sulcus (AL-STS). The late activity, peaking at 242-274 ms, was located ventro-rostrally over three electrodes. Among the four electrodes with motion VEPs, cortical stimulation at the most caudal pair elicited motion-in-depth perception involving the whole visual field. In addition to two subregions revealed on the gyral crown, magnetoencephalography (MEG) demonstrated another subregion with a late motion VEF in AL-STS immediately rostral to the electrode with the early motion VEP. CONCLUSIONS: In combination with MEG recording, the present invasive exploration demonstrated human MT+ in a focal area of the temporo-parieto-occipital junction and delineated possible three subregions as indicated by the different latencies and distributions of the motion VEP/VEFs. SIGNIFICANCE: Comparative MEG and direct electrocorticographic recordings delineated possible subregions within the human MT complex.

Adolescent↗

PubMed2004

Prototype of simulation of orthognathic surgery using a virtual reality haptic device.

A maxillofacial simulator can support education and training. In the present study, cutting, separation, and quantitative rearrangement of bone during orthognathic surgery were simulated by means of a haptic device with virtual tactile perception. Computed tomographic (CT) images of two patients with severe jaw deformity, one women and one man, were input into the device. In the woman, Le Fort I osteotomy of the maxilla and sagittal splitting ramus osteotomy of the mandible were initially simulated. During surgery with the haptic device, separation and rearrangement of the maxilla and the ramus of the mandible were initially processed. However, there was discrepancy and overlapping of the ramus with the mandible. Intraoral vertical osteotomy of the right ramus was then performed, with satisfactory results and less discrepancy and interference. The simulation was referred to at surgery, and satisfactory surgical assistance was postoperatively confirmed on CT images. The male patient had severe jaw deformity due to unequal growth between the ramuses, resulting in anterior crossbite. Sagittal splitting ramus osteotomy with rotation of the mandible was successfully simulated. Because of its versatility and functions, the present device was found to be useful for simulating various procedures for orthognathic surgery and thereby three-dimensionally determine surgical movements.

Adult↗

PubMed2004

Training in tooth preparation utilizing a support system.

Tooth preparation is an essential technique for dental treatment, but it is a skill not easily learned by a dental student. To facilitate this leaning process, a new tooth preparation support system with a parallel link mechanism was developed. This study reports the educational efficiency of this system for dental students. Dental students with no experience in clinical practice were selected and divided into two groups; one trained with this support system; and the other, with freehand preparation. They prepared axial walls in right maxillary second premolars and molars mounted in a phantom manikin with an air-turbine handpiece. Convergence angles of the axial walls and parallelisms between axes of prepared teeth were evaluated. Training with the support system led to significantly smaller convergence angles and parallelisms as compared with freehand preparation training. With the freehand preparation after training, the convergence angles and parallelisms became smaller in the group trained with the support system than those trained with freehand. The above findings suggest that training in tooth preparation utilizing the newly developed support system can be one of practical programs that are useful for dental students to achieve greater competency in tooth preparation.

Bicuspid↗

PubMed2004

Computer-assisted morphological analysis of dental casts with maxillary prognathism and reversed occlusion.

The morphologic characteristics of the dentition with maxillary prognathism and reversed occlusion were examined by a computer-assisted dental cast analysing system. Dental casts with normal occlusion, maxillary prognathism and reversed occlusion were selected and measured by a 3D shape measuring system. The dental arches and anteroposterior occlusal curves were approximated numerically by the polynomial expression with a fourth order and second order coefficients, respectively. The coefficients were analysed statistically. Maxillary dental arches with mandibular prognathism showed a more acuminate shape (V-shape) with a significant larger second order coefficient, while arches with reversed occlusion showed more angulate shapes (U-shape) with significantly smaller second order coefficients compared with arches with normal occlusions. However, a notable difference in the shape of the mandibular dental arches was not observed. The mandibular dental arches with maxillary prognathism were positioned backward relative to maxillary dental arches, while the arches with reversed occlusion were positioned forward. The anteroposterior occlusal curves with maxillary prognathism showed larger curvatures in maxilla and mandible, while the curves with reversed occlusion showed smaller curvatures in mandible comparing with the curves with normal occlusion. These results suggest that the present method could offer a useful and objective examination technique for the diagnosis of malocclusion.

Adolescent↗

PubMed2003

A neurofibromatosis type 1 patient with severe kyphoscoliosis and intrathoracic meningocele.

The patient presented with neurofibromatosis and a dystrophic kyphoscoliosis around the cervico-thoracic junction. When the patient was 59 years old, he started to suffer from dyspnea caused by an intrathoracic meningocele in the upper left thoracic cavity. A wide laminectomy from T2 to T5 was performed and the meningocele was resected. Although the dyspnoea disappeared postoperatively, the patient started to neurologically deteriorate. Laminectomy alone caused instability around the apex of the kyphosoliosis and spinal cord compression. Halo cast was applied and brought remarkable recovery of neurologic deficits. This result encouraged us to perform posterior fusion in situ from C3 to L2 with bone graft from the iliac crests and the Luque technique in conjunction with the Isola system. This resulted in the patient being able to walk again. The removal of the posterior element predisposes the patient to unstable postlaminectomy kyphosis and removes valuable bone stock required for posterior spinal fusion. For this reason, spinal fusion should have been conducted during surgery for the patient's meningocele.

Bone Transplantation↗

PubMed2003

A case of mucopolysaccharidosis IV with lower leg paresis due to thoraco-lumbar kyphoscoliosis.

We treated a patient of type IV mucopolysaccharidosis (Morquio's disease) with lower leg paresis due to kyphoscoliosis. A 65-year-old woman presented with Morquio's disease. A lateral radiograph demonstrated the classic bullet-shaped vertebrae and a 65 degrees thoraco-lumbar kyphosis. After the age of 60, she suffered from numbness in both lower legs and walking disturbance. Bilateral patellae-tendon reflexes were exaggerated. MRI showed compression of the spinal cord around T12 to L2 with a highlighted area of change inside the spinal cord. Myelography and computed tomography after the myelography showed narrowing of the sub-arachnoidal space and deformation of the spinal cord around the T12 to L2 levels. Severe vertebral osteoporosis made it necessary to first perform posterior correction of the kyphosis and fusion. The curve was stabilised with the Luque method from T7 to L4. Her neurological condition markedly recovered, but 1 year after surgery her neurological condition again began to deteriorate, resulting in walking disturbance. For this reason, anterior decompression and fusion through a lateral thoracotomy was undertaken. Decompression of the spinal cord and a bone graft from the iliac crest were attained. The patient's neurological condition again improved, but not as much as immediately after the first operation.

Aged↗