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Satoshi Yamaguchi

Publications and source records attributed to Satoshi Yamaguchi.

At least 19 recordsLinked to original sources
PubMed2007

Comparison of 4 MV photon surface dose among Varian, Siemens, and Elekta linear accelerators for tangential breast treatment: a phantom study.

PURPOSE: We have compared the differences in a 4-MV photon surface dose among Varian, Siemens, and Elekta linear accelerators (linacs) with wedges for tangential breast treatment. MATERIALS AND METHODS: The wedge factor and the surface dose were measured using a solid water phantom and an ion chamber for each linear accelerator with various field sizes and wedge angles. A tangential treatment plan was applied to an elliptical hollow cylinder water phantom with a radiochromic film placed thereon. A dose was delivered to a simulated target in the phantom, and the resulting dose distribution was analyzed using a film scanner. RESULTS: Varian's wedges resulted in the highest wedge factors, ranging from 0.37 to 0.75 depending on the wedge angles. Varian's wedges led to the highest normalized skin doses, ranging between 0.40 and 0.73 depending on the wedge angles and field sizes. In the cylinder phantom test with two tangential beams, the Varian linac provided a nearly 20% higher maximum dose than the Siemens and Elekta linacs. CONCLUSION: The Varian linac resulted in the highest surface doses, and the Elekta linac led to the lowest for nearly all the measurement conditions we employed, including open beams.

Breast Diseases↗
PubMed2006

Mucosa-associated lymphoid tissue lymphoma of the transverse colon: a case report.

We herein present a case of a 75-year-old female with mucosa-associated lymphoid tissue (MALT) lymphoma of the transverse colon with the stage IE (Ann Arbor classification). Colonoscopy revealed the tumor's appearance as a IIa plus II c-like early colon cancer as defined according to the macroscopic classification of the Japanese Research Society for Cancer of Colon, Rectum and Anus, measuring less than 2 cm in diameter. Histologically, the tumor was diagnosed as MALT lymphoma because of the presence of lymphoepithelial lesions consisting of diffuse proliferation of atypical lymphocytes and glandular destruction. The majority of these lymphocytes immunohistochemically stained for the B-lymphocyte marker. The patient first underwent H pylori eradication therapy with Lansap. However, the tumor size gradually increased over the next 4 mo and the patient eventually underwent surgical resection. The operative procedure included a partial colectomy with dissection of the paracolic lymph nodes. The tumor measured 45 mm multiply 30 mm in diameter and histological examination showed that the lymphoma cells had infiltrated the muscle layer of the colon without nodal involvement. The patient has had no recurrence postoperatively without any chemotherapy.

Aged↗
PubMed2006

Overlapping expression of FoxA and Zic confers responsiveness to FGF signaling to specify notochord in ascidian embryos.

Differences in cell responsiveness to an inductive signal contribute to the emergence of a variety of tissue types during animal development. In ascidian embryos, the Fibroblast Growth Factor (FGF) signal secreted from endoderm cells induces several different tissue types, such as notochord, mesenchyme and brain, at different positions in the embryo at the 32-cell stage. We show here in Halocynthia roretzi that FoxA and Zic are required for notochord formation in cells that receive the FGF signal. We also show that these transcription factors, only when both are supplied, are able to induce ectopic expression of the brachyury gene, a notochord-specific marker, in cells of all the three germ layers in an FGF-dependent manner. These results suggest that FoxA and Zic confer notochord-specific responsiveness to FGF signaling. Further analyses including knockdown and over-expression experiments showed that combinatorial inputs from maternally supplied and zigotically activated factors lead to overlapping expression of FoxA and Zic in the presumptive notochord cells, which eventually activate the expression of the brachyury gene in cooperation with FGF signaling. Our data illustrate how a complex gene network specifies the notochord at its specific position within the embryo.

Animals↗
PubMed2006

Long term results of anterior cruciate ligament reconstruction with iliotibial tract: 6-, 13-, and 24-year longitudinal follow-up.

Many studies have reported successful outcomes less than 10 years after anterior cruciate ligament (ACL) reconstruction. However, longer-term outcomes have not been analyzed. We assessd outcomes 24 years after anterior cruciate ligament reconstruction with iliotibial tract and compared them with shorter-term results in the same patients. Between 1979 and 1981, 45 patients underwent combined intra- and extra-articular ACL reconstruction with iliotibial tract. Follow-up evaluations of these patients were performed at 6, 13, and 24 years after surgery, which included manual and instrumental laxity testing, functional assessments, and radiography. Twenty-six (60%) patients of the original ACL reconstruction cohort participated in all three follow-up assessments. Three patients had undergone meniscectomy prior to ACL reconstruction and 18 underwent meniscectomy together with ACL reconstruction. Eleven patients underwent subsequent meniscectomy. The mean Lysholm score was 96.2, 93.8, and 87.8 at 6-, 13-, and 24-year follow-up, respectively. A significant decrease in mean Lysholm score was found between 13- and 24-year follow-up. The mean KT-1000 side-to-side difference was 3.5 mm at 24-year follow-up. Overall knee laxity did not change significantly during the follow-up period. At 24-year follow-up, 17 (71%) patients had moderate or severe degenerative changes on radiographs although about 50% of the patients participated in regular sports activities and no patient required regular clinical intervention.

Adolescent↗
PubMed2006

Small bowel anisakiosis: a report of two cases.

Small bowel stenosis is a serious complication of intestinal anisakiosis. The aim of this report is to investigate whether severe stenosis of the small intestine can be conservatively managed. We treated two patients with severe stenosis of the small intestine caused by anisakiosis. Surgical intervention was eventually performed on the 23rd and 35th in the hospital, respectively. Histopathological examination of the resected specimens revealed that the intestinal wall had been completely damaged by the inflammatory reaction of anisakiosis, and that the damage was irreversible, thereby suggesting that laparotomy is needed in cases of severe small bowel stenosis caused by intestinal anisakiosis, even if a long period of conservative treatment for the intestinal anisakiosis allowed the patient to pass successfully through the acute phase.

Animals↗
PubMed2006

The effects of neuronal induction on gene expression profile in bone marrow stromal cells (BMSC)--a preliminary study using microarray analysis.

Bone marrow stromal cells (BMSC) have been anticipated as a donor for cell type for transplantation therapy in various neurological disorders. However, their neurogenic capacity still remains undetermined. In this study, we aimed to clarify whether in vitro chemical treatment promotes their neuronal differentiation on the level of gene expression. Mice BMSC were cultured with medium supplemented with DMSO, retinoic acid, and basic fibroblast growth factor, and their morphology and expression of neuronal markers were evaluated. Subsequently, using microarray and RT-PCR techniques, the treatment-induced changes in the gene expression profile were analyzed. After exposure to the medium, the BMSC simulated a neuron-like appearance and increased their immunoreactivity for nestin and Tuj-1. Microarray analysis revealed that the BMSC per se express the multilineage cellular genes, including those associated with the neuron. Chemical treatment significantly decreased the expression of genes related to mesenchymal cells and increased the expression of 5 neuron-associated genes. Microarray and RT-PCR analyses also demonstrated that the BMSC express the genes for several growth factors including NGF-beta and BDNF, indicating their therapeutic role in protecting the injured central nervous system. The present results suggest that at least a certain subpopulation of the BMSC have the potential to alter their gene expression profile in response to the surrounding environment and may possibly protect the host tissue by secreting neuroprotective factors.

Animals↗
PubMed2006

Nonsuture dural repair using polyglycolic acid mesh and fibrin glue: clinical application to spinal surgery.

BACKGROUND: In spinal surgery, repair of the dura is difficult when it is torn or fragile or is ossified as in cases with ossification of posterior longitudinal ligament. We report our experience with a nonsuture dural repair technique in patients undergoing spinal surgery; it uses a dura substitute composed of polyglycolic acid (PGA) mesh and fibrin glue. Here, we report the efficacy and safety of nonsuture duroplasty using PGA mesh and fibrin glue (PGA-fibrin sheet). METHODS: The artificial dura mater is composed of a PGA-fibrin sheet. The dural defect is covered with a patch sprayed with fibrin glue without suturing to the dura mater. We first evaluated this technique in an experimental study by performing water leakage tests. Between May 2001 and January 2005, we used it in 160 spinal surgeries that required intraoperative dura repair. RESULTS: Our preliminary tests showed that the threshold for water pressure without leakage was 161 +/- 42 and 96.5 +/- 32 mm Hg when the unsprayed margin around the perimeter of the patch was 5 and 2 mm, respectively. Of the 160 operated patients, 10 (6.3%) experienced subcutaneous cerebrospinal fluid (CSF) leakage. Of these, 6 required a second operation; in the other 4, the CSF collection diminished spontaneously. There were no other complications such as allergic reaction, adhesion, or infection. CONCLUSION: In combination with CSF diversion, the PGA-fibrin sheet is a viable alternative method for dural repair in spinal surgery.

Arnold-Chiari Malformation↗
PubMed2006

Effect of age and education on the Trail Making Test and determination of normative data for Japanese elderly people: the Tajiri Project.

The Trail Making Test (TMT) is a common two-part neuropsychological test, in which visuospatial ability (TMT-A) and executive function (TMT-B) are evaluated. Normative data for this test have not been reported for Japanese subjects; therefore, the purpose of the present paper was to investigate the effect of age and education on the TMT in 155 healthy elderly adults with clinical dementia rating 0 (healthy). The participants were classified into three groups based on age (70-74 years, 75-84 years and >or=85 years), and also into three groups based on educational level (6 years, 8 years and >or=10 years). The time to complete TMT-A and TMT-B were measured, and the difference in score between TMT-A and TMT-B (B-A) and the ratio of the score (B/A) were calculated as indices of executive function. The time for completion of both parts of the TMT increased markedly in the >or=85-years group. For TMT-A, there was a significant difference between the 6-years and 8-years groups, and between the 6-years and >or=10-years groups, and for TMT-B, there was a significant difference between the 6-years and >or=10-years groups, and between the 8-years and >or=10-years groups. The difference and ratio scores increased in the >or=85-years group, but the educational level did not significantly influence these scores. Our data suggest that cognitive functions evaluated by TMT-A and TMT-B are not affected by aging until the subjects are >or=85 years old. For TMT-A, an educational effect becomes apparent when the population includes poorly educated subjects, but this part of the test is not affected by educational level provided that the subjects have some education (>6 years). The time to complete TMT-B is affected by educational level, consistent with previous reports. However, when adjusted using the results for TMT-A [(B-A) or (B/A)], the educational effect on executive function disappeared. Thus, the effect of educational level on executive function was unclear in normal elderly subjects.

Aged↗
PubMed2006

Improvement of stone comminution by slow delivery rate of shock waves in extracorporeal lithotripsy.

AIM: The aim of this study was to investigate the effect of delivery rate of shockwaves (SW) on stone comminution and treatment outcomes in patients with renal and ureteral stones. METHODS: Patients with radio-opaque stones in the upper urinary tract that were treated by extracorporeal shock wave lithotripsy (ESWL) were divided into two groups according to delivery rate (120 or 60 SW/min). The effective fragmentation after one ESWL session and treatment success at 3 months after ESWL was compared between the two groups. RESULTS: Of 134 patients (84 men and 50 women), 68 patients were treated at a fast rate and 66 were treated at a slow rate. Thirty and 38 patients in the fast rate group and 28 and 38 in the slow rate group had renal and ureteral stones, respectively. After one ESWL session, effective fragmentation was noted more often in the slow group (65.2%) than the fast group (47.1%) (P = 0.035), particularly for smaller stones (stone area <100 mm(2)) (P = 0.005) and renal stones (p = 0.005). However, there was no significant difference in treatment success at 3 months after ESWL between the two groups. In univariate logistic regression analysis, slow SW rate and smaller stones were significant factors for effective fragmentation after one ESWL session. In multivariate analysis, slow SW rate and smaller stones were also independent factors. CONCLUSIONS: Slow SW rate contributed to better stone comminution than fast rate, particularly for small stones and renal stones. ESWL treatment at a slow SW rate is recommended to obtain efficient stone fragmentation.

Adolescent↗
PubMed2006

Gas chromatography/multiphoton ionization/mass spectrometry of polychlorinated dibenzofurans using nanosecond and femtosecond lasers.

Gas chromatography/multiphoton ionization/time-of-flight mass spectrometry (GC/MPI/TOF-MS) using a femtosecond laser source has been developed and applied to analysis of an authentic sample containing five polychlorinated dibenzofurans (PCDFs). The ionization efficiency was substantially improved for compounds such as tetrachlorinated dibenzofuran (tetraCDF) and pentachlorinated dibenzofuran (pentaCDF) using a femtosecond laser, instead of a nanosecond laser currently used for this purpose. The relatively poor efficiencies in nanosecond ionization can be attributed to the short lifetimes of the singlet excited states that are efficiently relaxed to triplet levels by intersystem crossing. The detection limits for pentaCDF isomers, i.e., 1,2,3,8,9-pentaCDF (non-toxic) and 1,2,3,7,8-pentaCDF (toxic), were determined to be ca. 100 pg, when the femtosecond laser was employed. The present method has the potential for use in the detection and determination of toxic PCDD/Fs in exhaust gas from an incinerator, because of the high inherent selectivity of GC and the high sensitivity of MPI/TOF-MS.

Journal Article↗
PubMed2006

Poor prognosis of patients with stage Ib1 adenosquamous cell carcinoma of the uterine cervix with pelvic lymphnode metastasis.

From January 1990 to December 2004, the prognosis of 28 patients with stage Ib1 adenosquamous cell carcinoma (ASC) were assessed in comparison with those of matched counterparts of pure adenocarcinoma (ADC) and squamous cell carcinoma (SCC). The mean ages were 46.6, 48.3, and 48.5 years for patients with ASC, ADC, and SCC, respectively. All the patients underwent radical hysterectomy with pelvic lymphadenectomy and postoperative adjuvant therapy was given to the patients with positive pathological risk. The incidence of lymph node metastasis for ASC at 21.4% was not significantly different from those for ADC (13.6%) and SCC (15.8%). There was also no significant difference in the incidence of lymphatic or vascular space involvement (LVSI) and depth of stromal invasion between three cell types. Since the tumor sizes of all ASC cases examined in this study were less than 4 cm, the prognoses were compared among stage Ib1 disease according to the classification system of the International Federation of Gynecology and Obstetrics (FIGO). The overall 5-year survival rates of stage Ib1 ASC, ADC, and SCC were 82.4%, 92.4%, and 94.0%, respectively, suggesting poor prognosis of ASC, but there was no significant difference. Patients with stage Ib1 ASC were retrospectively assigned to a low- or high-risk group based on the surgical-pathologic factors including positive lymph node metastasis, 2-4 cm of tumor size, positive LVSI, and/or deep stromal invasion. While all 9 patients in the low-risk group are alive without disease, 7 of the 19 patients in the high-risk group developed recurrence. The overall 5-year survival rates were 100% for a low risk group and 74.8% for a high-risk group, respectively, but this difference did not reach statistical significance. However, the prognosis of high-risk patients with lymph node metastasis was significantly (p=0.01) worse than low-risk group. The present study suggests that ASC histology appears to carry a poor prognosis than SCC, but low-risk group of stage Ib1 ASC has a good prognosis without postoperative adjuvant therapy.

Adenocarcinoma↗
PubMed2005

Influence of estrus status on urinary chemical parameters related to urolithiasis.

The present study examines the urinary chemical parameters related to urolithiasis in healthy female volunteers during premenopause and menopause, and discusses the role of menopause in stone formation. We investigated 24-h urine parameters associated with urinary stones and focused upon estrus status. Participants comprised 30 healthy women, 15 childless, premenopausal women and 15 menopausal women without a history of urolithiasis. Our results showed that menopausal women have lower citrate and higher calcium excretion, which might enhance calcium stone crystallization. We propose that the estrus status of female patients should be considered when evaluating metabolic abnormalities.

Adult↗
PubMed2005

Ovarian metastasis in carcinoma of the uterine cervix.

BACKGROUND: The present study was conducted to determine the frequency and clinicopathological features of ovarian metastasis in a large population of patients with stage Ib-IIb cervical cancer. METHODS: The study population consisted of 3471 patients with stage Ib to IIb cervical cancer who underwent radical hysterectomy, including pelvic lymphadenectomy and bilateral salpingo-oophorectomy, at our six institutions between 1981 and 2000. To our knowledge, this study is the largest review of patients with ovarian metastasis from cervical cancer. We reviewed the patients' medical records to determine clinicopathological features. RESULTS: Fifty-two patients (1.50%) had ovarian metastases: 6 in stage Ib1, 12 in stage Ib2, 5 in stage IIa, and 29 in stage IIb. The mean age of patients with ovarian metastasis was 49.9 years (range: 29-73 years). The incidence of ovarian metastasis in patients with cervical cancer was 0.22% for stage Ib, 0.75% for stage IIa, and 2.17% for stage IIb with squamous cell carcinoma, and 3.72%, 5.26%, and 9.85%, respectively, in adenocarcinoma. Ovarian metastasis occurred more frequently among patients with adenocarcinoma than among those with squamous cell carcinoma (5.31% vs. 0.79%). Outcome for patients with ovarian metastasis was very poor and not related to FIGO stage and histological type. The presence of ovarian metastasis did not correlate with lymph node involvement or parametrial invasion. CONCLUSION: Study results indicate that ovaries can be preserved in patients with stage Ib-IIa squamous cell carcinoma but removed in all patients with adenocarcinoma.

Adenocarcinoma↗
PubMed2005

Cooperation between artificial receptors and supramolecular hydrogels for sensing and discriminating phosphate derivatives.

This study has successfully demonstrated that the cooperative action of artificial receptors with semi-wet supramolecular hydrogels may produce a unique and efficient molecular recognition device not only for the simple sensing of phosphate derivatives, but also for discriminating among phosphate derivatives. We directly observed by confocal laser scanning microscopy that fluorescent artificial receptors can dynamically change the location between the aqueous cavity and the hydrophobic fibers upon guest-binding under semi-wet conditions provided by the supramolecular hydrogel. On the basis of such a guest-dependent dynamic redistribution of the receptor molecules, a sophisticated means for molecular recognition of phosphate derivatives can be rationally designed in the hydrogel matrix. That is, the elaborate utilization of the hydrophobic fibrous domains, as well as the water-rich hydrophilic cavities, enables us to establish three distinct signal transduction modes for phosphate sensing: the use of (i) a photoinduced electron transfer type of chemosensor, (ii) an environmentally sensitive probe, and (iii) an artificial receptor displaying a fluorescence resonance energy transfer type of fluorescent signal change. Thus, one can selectively sense and discriminate the various phosphate derivatives, such as phosphate, phospho-tyrosine, phenyl phosphate, and adenosine triphosphate, using a fluorescence wavelength shift and a seesaw type of ratiometric fluorescence change, as well as a simple fluorescence intensity change. It is also shown that an array of the miniaturized hydrogel is promising for the rapid and high-throughput sensing of these phosphate derivatives.

Hydrogels↗
PubMed2005

Photodynamic therapy for cervical intraepithelial neoplasia.

OBJECTIVES: Photodynamic therapy (PDT) is a minimally invasive treatment for cervical intraepithelial neoplasia (CIN). We report the effectiveness of PDT in 105 cases of CIN. METHODS: All patients received photofrin (PHE) 2 mg/kg intravenously and, 48-60 h later, phototherapy was performed using the Excimer dye laser or a YAG-OPO laser with an irradiation dose of 100 J/cm(2) using 630 nm wavelength. RESULTS: Mild photosensitivity occurred in 48% (50/105) of patients. The complete response (CR) rate was 90% (94/105) at 3 months following treatment. In the remaining 11 patients, 5 patients had CIN1, 2 patients had CIN2, and 4 patients had mild cytologic findings. However, in 9 of these 11 patients, CR was achieved 6 months after PDT. In 69 patients, human papilloma virus (HPV) typing was performed before and after PDT therapy. Pre-treatment, 64 of 69 patients (93%), were HPV-positive including 30 cases of high-risk HPV (43%). Testing performed 3, 6 and 12 months following PDT revealed no HPV-DNA in 75% (52/69), 74% (48/65) and 72% (41/57) of patients. At present, the median follow-up period is 636 days (90-2,232 days). In 3 patients, recurrence requiring surgical treatment was identified at 646, 717 and 895 days after PDT. CONCLUSIONS: PDT is an effective and minimally invasive treatment for CIN, which also appears to eradicate HPV infection.

Adult↗
PubMed2005

Different MRI findings for normal elderly and very mild Alzheimer's disease in a community: implications for clinical practice the Tajiri Project.

To investigate magnetic resonance imaging (MRI) findings of very mild dementia, 485 participants were randomly selected in a community. Three hundred and forty participants were of Clinical Dementia Rating (CDR) 0 (healthy), 113 were of CDR 0.5 (questionable dementia), and 32 were of CDR 1 and 2 (including 20 Alzheimer's disease, AD). Cortical atrophy, white matter lesion, etc., were visually assessed. We found that each part of the brain showed atrophy in older adults for CDR 0. For CDR 0.5, the relationships between MRI findings and age were weaker, and for AD, there were no such relationship. Atrophy related with dementia severity was found to be limited to the lateral and medial temporal lobes. For CDR 0.5, amygdala atrophy was the only finding indicating CDR effect but no age effect. The amygdala or anterior entorhinal atrophy is important for discriminating very mild dementia from normal elderly.

Age Factors↗
PubMed2005

Study of a rat model for calcium oxalate crystal formation without severe renal damage in selected conditions.

BACKGROUND: Although nephrotoxic in high doses, ethylene glycol (EG) has been used with ammonium chloride (NH(4)Cl) or vitamin D(3) to study calcium oxalate stone formation in rat models. In the present study we used EG alone or with NH(4)Cl to study hyperoxaluria, crystaluria, and crystal attachment to renal epithelial cells in rats with minimal renal damage. METHODS: Six-week-old male Sprague-Dawley (SD) rats were given food and special drinking water. In experiment 1 the drinking water contained 1.0% NH(4)Cl plus four different concentrations of EG (0.8%, 0.4%, 0.2%, 0.1%). In experiment 2 the drinking water contained EG alone (0.8%, 0.4%, 0.2%, 0.1%). Urine was collected for 24 h before the rats were sacrificed. In experiment 1 the rats were sacrificed 5-13 days after starting the special water. In experiment 2 the rats were sacrificed 7-21 days after starting the special water. Bladder urine was also obtained. Blood and urine were tested for calcium, phosphorus, and creatinine. In addition, urine was tested for pH, oxalate and N-acetyl-beta-D glucosaminidase (NAG). Kidney sections were stained with hematoxylin-eosin, von Kossa and Pizzolato stain. Crystal morphology was determined using polarizing microscopy, and composition was determined using high-resolution X-ray powder diffraction. RESULTS: Experiment 1: Aggravation of renal function, an increase in urinary oxalate and NAG excretion, and crystals observed in the kidneys all correlated with EG concentration and length of drinking time. In bladder urine, calcium oxalate monohydrate (COM) crystals exceeded calcium oxalate dihydrate (COD) crystals. Experiment 2: Renal function remained unchanged. Oxalate excretion increased and NAG increased slightly. Crystals occurred only in the papillary tip region. Crystals in bladder urine were mostly COD. CONCLUSION: In the current rat model, calcium oxalate crystaluria could be induced without severe renal damage in selected cases. Either and/or both COM and COD might form and interact with kidney epithelium. We propose different experimental conditions to study the various phases of calcium oxalate stone formation in young male SD rats.

Acetylglucosaminidase↗