PubMed Health⌕ Search

Biomedical subjects

Masato Hashimoto

Publications and source records attributed to Masato Hashimoto.

18 recordsLinked to original sources
PubMed2006

An equilibrium analysis of the aqueous H+-MoO4(2-)-(HP)O(3)2- and H+-MoO4(2-)-(HP)O(3)2--HPO4(2-) systems.

The speciation in the phosphitomolybdate system, H+-MoO4(2-)-(HP)O(3)2-, has been determined from combined potentiometric and 31P NMR measurements in 0.600 M Na(Cl) medium at 298(1) K. Potentiometric titration data were collected in the ranges 2.5<-log[H+]<6.2, 40.0<or=[Mo]tot<or=240.0 mM, 10.0<or=[P]tot<or=40.0 mM and 1<or=[Mo]tot/[P]tot<or=10. 31P NMR data were collected in the same ranges with the exception that -log[H+] was decreased to 0.8. The pKa values of phosphite were determined by means of potentiometric (1.5<-log[H+]<8.6) and 31P NMR chemical shift data (0.0<-log[H+]<12.0). The following log beta (3sigma) values were deduced: H(HP)O3-, 6.09(2); H2(HP)O3, 7.23(4) (pKa=1.14). In the phosphitomolybdate system, the following complexes were found along with their formation constants ((HP) denotes phosphite): Mo5(HP)2(4-), 65.31(4); Mo6(HP)(2)5-, 71.94(5); Mo5(HP)4-, 51.25(8); Mo5(HP)3-, 54.9(3); Mo6(HP)2-, 68.99(9); Mo7(HP)5-, 71.25(3); Mo7(HP)4-, 74.2(2). Because hydrolysis and oxidation of phosphite to phosphate were observed by NMR, with a mixed-hetero species of low [Mo]tot/[P]tot ratio being detected, the four-component H+-MoO(4)2--(HP)O3(2-)-HPO(4)2- system was also studied in the same way over the range 0.8<-log[H+]<6.2 and [Mo]tot/[P]tot fixed at 1.5. The following mixed heteropolyanion species have been found (P denotes the phosphate group): Mo5(HP)P5-, 62.27(6); Mo5(HP)P4-, 66.76(4). The equilibrium speciation in the two systems are illustrated by distribution diagrams. In addition, the aqueous structures are proposed for all the species formed in the systems.

Journal Article↗
PubMed2006

The reduced expression and aberrant methylation of p16(INK4a) in chromate workers with lung cancer.

STUDY OBJECTIVES: It is known that chromium is one of the important inhaled carcinogens that cause lung cancer. Our previous studies revealed a variety of genetic changes in lung cancers from chromate-exposed workers (chromate lung cancer). However, the epigenetic effects of chromium are not understood. MATERIALS AND METHODS: We investigated the methylation of the p16 gene using a methylation-specific PCR method in 30 chromate lung cancers and 38 non-chromate lung cancers, and the expression of the p16 protein using immunohistochemistry in 25 chromate lung cancers. RESULTS: Ten (33%) chromate lung cancers showed methylation of the p16 promoter region. On the other hand, 10 (26%) of the non-chromate lung cancers also showed it. The frequency of p16 methylation in non-chromate lung cancer was 0%, 33% and 30% for low (< or =600), moderate (<600, >1000) and high (> or =1000) Brinkman indexes, respectively. However, the frequency of p16 methylation in chromate lung cancer was constant, irrespective of the Brinkman index. In chromate lung cancer, patients with chromate exposure of less than 15 years never had p16 methylation, while 40% (> or =25 years) or 43% (> or =15, <25 years) of patients with chromate exposure of more than 15 years did. In chromate lung cancer, chromate exposure, not smoking, mainly influenced the p16 methylation. Most of the chromate lung cancers with p16 methylation (85.7%) showed repression of the p16 protein. CONCLUSIONS: We speculate that not only genetic but also epigenetic alterations are involved in the carcinogenesis due to chromium.

Adult↗
PubMed2005

Microsatellite instability and protein expression of the DNA mismatch repair gene, hMLH1, of lung cancer in chromate-exposed workers.

Our previous studies of lung cancer in chromate-exposed workers (chromate lung cancer) have revealed that the frequency of replication error (RER) in chromate lung cancer is very high. We examined whether the RER phenotype of chromate lung cancer is due to an abnormality of DNA mismatch repair protein. We investigated the expression of a DNA mismatch repair gene, hMLH1, and hMSH2 proteins using immunohistochemistry and microsatellite instability (MSI) in 35 chromate lung cancers and 26 nonchromate lung cancers. Lung cancer without MSI or with MSI at one locus was defined as "RER(-)," lung cancer with MSI at two loci was defined as "RER(+)," and lung cancer with MSI at three or more loci was defined as "RER(++)." The repression rate of hMLH1 and hMSH2 proteins in chromate lung cancer was significantly more than that of nonchromate lung cancer (hMLH1: 56% vs. 20%, P = 0.006, hMSH2: 74% vs. 23%, P < 0.0001). In chromate lung cancer, the repression rate for hMLH1 was 43% in RER(-), 40% in RER(+), and 90% in the RER(++) group. The repression rate of hMLH1 protein in the RER(++) group was significantly higher than that in the RER(-) and RER(+) groups (P = 0.039). The inactivation of hMLH1 expression strongly correlated with the microsatellite high instability phenotype in chromate lung cancer. The genetic instability of chromate lung cancer is due to the repression of hMLH1 protein.

Adaptor Proteins, Signal Transducing↗
PubMed2005

A case of posterior ischemic optic neuropathy in a posterior-draining dural cavernous sinus fistula.

A 79-year-old woman presented with sudden unilateral visual loss after an ocular motor disturbance and pulsatile tinnitus. Neuro-ophthalmologic examination showed a presumed right posterior ischemic optic neuropathy (PION), oculosympathetic, and third, sensory fifth, and sixth cranial nerve pareses. Selective angiography of the right internal and external carotid arteries confirmed a posterior-draining dural carotid cavernous sinus fistula (CCF) fed by the right meningohypophyseal trunk and right middle meningeal artery. Angiography also showed an ophthalmic-middle meningeal arterial anastomosis. We postulate that the PION was caused by an arterial steal, because blood was drawn into the fistula and away from the intraorbital optic nerve.

Aged↗
PubMed2004

High incidence of orbital malignant lymphoma in Japanese patients.

PURPOSE: To review 244 cases of orbital tumors to determine pathologic findings in Japanese patients. DESIGN: Observational case series. METHODS: We studied the pathology and origin of tumors in the orbit in 244 consecutive Japanese patients with orbital tumors at our institution from 1981 through 2002 (age 0 to 90 years, mean, 48.7 years; 114 men, 130 women). RESULTS: The most common tumors were lymphoproliferative diseases (n = 114, 42.5%), including malignant lymphoma (n = 59, 24.1%) and reactive lymphoid hyperplasia (n = 45, 18.4%), pleomorphic adenoma (n = 21, 8.6%), and cavernous hemangioma (n = 18, 7.4%). CONCLUSION: The incidence of lymphoproliferative diseases, especially malignant lymphoma, was very high in Japanese patients.

Adolescent↗
PubMed2004

Superior oblique myokymia caused by vascular compression.

A 49-year-old man had left superior oblique myokymia for eight years. Magnetic resonance images with enhanced spoiled gradient recalled acquisition in the steady state (SPGR) and flow imaging using steady acquisition (FIESTA) disclosed a branch of the superior cerebellar artery lying on the root exit zone of the left trochlear nerve. Posterior fossa craniotomy confirmed the imaging findings. A Teflon pad was placed between the compressing artery and the trochlear nerve. The patient's superior oblique myokymia has completely resolved with a one-year follow-up. Only one such case has been previously reported. This is the first report to display the imaging findings.

Cerebral Arteries↗
PubMed2003

Effect of steroid pulse therapy with and without orbital radiotherapy on Graves' ophthalmopathy.

PURPOSE: To report the effect of high-dose intravenous corticosteroid pulse therapy with and without orbital radiotherapy on Graves' ophthalmopathy. DESIGN: Nonrandomized clinical trial. METHODS: We selected 39 Japanese patients (age range, 22-64 years; mean, 48 years; 31 women, 8 men) who had active Graves' ophthalmopathy among 195 consecutive patients. In the first 20 patients, high-dose intravenous methylprednisolone pulse therapy (1 g per day for 3 successive days, repeated 3 times within 3 weeks) followed by 24-Gy orbital radiotherapy was performed. In the other 19 of the 39 patients, high-dose intravenous methylprednisolone pulse therapy without orbital radiotherapy was performed. Coronal computed tomography (CT) of the orbit and exophthalmometry were performed before the corticosteroid pulse therapy, and 1 and 6 months after the corticosteroid pulse therapy. The maximum coronal section area of the most hypertrophic rectus muscle in each eye was measured based on orbital CT imaging. RESULTS: Clinical findings at study entry were not significantly different between the two groups. No significant difference was found in the maximum coronal section area of the most hypertrophic rectus muscle and the results of exophthalmometry measurements in both groups before the therapy. Extraocular muscle hypertrophy was significantly reduced 1 month and 6 months after the therapy (P < .01) in both groups. However, no beneficial therapeutic effect on proptosis was observed in either group at 1 month and 6 months after the therapy. No significant difference in the therapeutic effect on extraocular muscle hypertrophy and proptosis was found between the two groups. CONCLUSIONS: Orbital irradiation after corticosteroid pulse therapy had no beneficial therapeutic effects on rectus muscle hypertrophy or proptosis of active Graves' ophthalmopathy during the 6-month follow-up period.

Adult↗
PubMed2003

Three-dimensional eye movement analysis of superior oblique myokymia.

PURPOSE: To confirm the idea that sole contraction of the superior oblique muscle causes attacks of superior oblique myokymia (SOM). DESIGN: Observational case report. METHODS: A 43-year-old man presented with episodic monocular oscillatory eye movements. Three-dimensional eye movements were recorded using the magnetic search coil system and analyzed as rotation vector. The attacks of SOM consisted of intorsional, depressive, and abductive fast phases and their exponential decaying slow phases. RESULTS: Average direction of rotation axis for the fast phases while fixating straight ahead was 51.5 +/- 5.4 degrees from depression axis in vertical-torsional plane, 78.7 +/- 4.4 degrees from abduction axis in horizontal-torsional plane, and 76.3 +/- 4.3 degrees from abduction axis in horizontal-vertical plane (+/-SD, n = 50). Time constants of slow phases were less than 0.1 second. CONCLUSIONS: Quantitative three-dimensional analysis of SOM directly confirmed that the fast phases of SOM attacks were induced by the sole contraction of the superior oblique muscle.

Adult↗
PubMed2003

[Epidemic nosocomial keratoconjunctivitis caused by adenovirus type 4].

PURPOSE: To evaluate the clinical features of nosocomial epidemic keratoconjunctivitis(EKC) occurring in the ophthalmology ward of Sapporo Medical University Hospital and to devise preventive measures for it. MATERIALS AND METHODS: We studied the symptoms and clinical course of 2 patients who had EKC and 16 patients who had EKC caused by nosocomial infections in our hospital. We attempted to detect adenovirus antigen and viral DNA from conjunctival swabs and also to isolate the virus. RESULTS: The clinical symptoms of EKC were conjunctival hyperemia in 18 patients(100%), conjunctival follicles in 11 patients (61.1%), discharge in 8 patients(44.4%), superficial punctate keratopathy in 7 patients(38.9%), swelling of the eyelids in 3 patients(16.7%), and fever in 3 patients(16.7%). 72% were positive for Adeno-check. Adenovirus type 4 was isolated from the conjunctival swabs. We considered that the route of hospital infection was infection from the doctor's hands, from eye drops, and from contact lenses. We disclosed that nosocomical EKC had occurred in our hospital. The hospital infection was eliminated by closing the ophthalmology ward and sterilizing instruments and washing hands. CONCLUSIONS: The delay of proper measures increased the risk of nosocomical infection. We recognized the importance of careful observation of patients and immediate preventive efforts in nosocomical infection.

Adenovirus Infections, Human↗
PubMed2002

[Ni(H2O)6]2[Na(H2O)3]2[V10O28].4H2O, bis(nickel hexahydrate) bis(sodium trihydrate) decavanadate tetrahydrate.

Polyoxometallates are capable of including transition metals in their crystal structures as either discrete cations or heteroatoms. The title compound crystallizes with triclinic symmetry and consists of a centrosymmetric [V(10)O(28)](6-) anion, a trimeric [Na(H(2)O)(3)][Ni(H(2)O)(6)][Na(H(2)O)(3)](4+) cation, an [Ni(H(2)O)(6)](2+) cation and four water molecules of crystallization. The compound possesses two Ni atoms (each on independent inversion centres), one as a discrete cation and one in a disodium-nickel trimeric cation involved in the one-dimensional polycation-polyanion hybrid polymer. The polymers are bound together via hydrogen bonds to the water molecules and the nickel(II) hexahydrate cation. Several structures of decavanadate compounds having transition metal atoms, monovalent cations and [V(10)O(28)](6-) anions in the ratio 2:2:1 have been reported previously. However, the present compound differs from these in its arrangement of monovalent cations and transition metal atoms.

Journal Article↗
PubMed2002

Frequent microsatellite instability in lung cancer from chromate-exposed workers.

Although chromium has been the most extensively investigated metal with respect to mutagenicity and carcinogenicity, its genetic effects in humans are only partly understood. Our previous study demonstrated that lung cancer from chromate-exposed workers infrequently (20%) displayed p53 gene mutations as well as a particular mutation pattern. In the present study, we examined the replication error (RER) and loss of heterozygosity (LOH) in 38 lung cancers from 28 chromate-exposed workers (chromate lung cancer group) and in 26 lung cancer patients without chromate exposure (non-chromate lung cancer group), using six microsatellite markers containing CA repeats: D3S647 (3p23), D3S966 (3p21.3), D3S1289 (3p21.1), D5S346 (5q21-q22), D9S161 (9p21), and TP53 (17p13.1). The RER phenotype was defined as the presence of microsatellite instability (MSI) at two or more loci. Thirty (78.9%) of 38 tumors in the chromate lung cancer group exhibited RER. In contrast, only four (15.4%) of 26 tumors in the non-chromate lung cancer group exhibited RER. The frequency of RER in the chromate lung cancer group was significantly higher than that in the non-chromate lung cancer group (P < 0.0001). By contrast, the frequency of LOH at 3p, 5q, 9p, and 17p loci in tumors with chromate exposure was not significantly different from that in tumors without chromate exposure. In the chromate lung cancer group, the period of chromate exposure in workers with RER (24.5 +/- 6.7 yr) was significantly longer than that in workers without RER (17.0 +/- 3.5 yr) (P = 0.0046). In addition, a longer period of chromate exposure was associated with a tendency toward a higher frequency of MSI. This finding suggests that MSI may play a role in chromium-induced carcinogenesis. In addition to our previous study of p53 mutations, the present findings suggest that the carcinogenic mechanism of chromate lung cancer may differ from that of non-chromate lung cancer.

Adult↗
PubMedDate not supplied

N-acetylaspartate concentration in the chiasm measured by in vivo proton magnetic resonance spectroscopy.

PURPOSE: To measure the concentration of N-acetylaspartate (NAA) in the chiasm of both normal controls and patients with chiasmal optic neuritis by in vivo proton magnetic resonance spectroscopy (1H-MRS). METHODS: Ten normal subjects (age range, 22 to 40 years; mean, 31 years; seven men and three women) and two patients with chiasmal optic neuritis were examined at the Sapporo Medical University Hospital. Localized 1H-MRS spectra of the chiasm were obtained using a whole-body 1.5-T magnetic resonance system. RESULTS: 1H-MRS spectra of the chiasm were obtained in all subjects. The level of NAA concentration in the optic chiasm was 15.73 +/- 1.43 mM (mean +/- SD) in normal subjects. In contrast, the NAA levels in the two patients with chiasmal optic neuritis were significantly lower (P < 0.001). The level of NAA in the two patients was significantly increased after improvement of visual acuity and visual fields following corticosteroid pulse therapy. CONCLUSIONS: These results suggest that 1H-MRS enables us to estimate the concentration of NAA in the chiasm. The NAA concentration in the optic nerve measured by 1H-MRS may be a new clinical parameter to monitor the axonal damage following optic neuritis.

Adult↗
PubMedDate not supplied

A review of 244 orbital tumors in Japanese patients during a 21-year period: origins and locations.

PURPOSE: To review 244 cases of orbital tumors to determine the distribution of patient age, pathology, and tumor origin and location. METHODS: We reviewed cases of histopathologically or radiologically verified orbital tumors at our institution from 1981 through 2002, and studied the distribution of patient age, pathology, origin of tumors, and tumor location in the orbit in 244 consecutive patients (aged from 0 to 90 years, mean, 48.7 years; 114 men, 130 women). RESULTS: Among the 244 cases, 213 (89%) were primary orbital tumors, 23 (9%) were secondary tumors originating in contiguous spaces, and 8 (2%) were metastatic tumors. Regarding the location in the orbit, 122 tumors (50%) were extraconal, 36 (15%) were intraconal, and 86 (35%) were in the lacrimal gland area. The common tumors were reactive lymphoid hyperplasia (22%) and malignant lymphoma (20%) in the extraconal area; cavernous hemangioma (25%), optic nerve glioma (14%), and optic nerve sheath meningioma (14%) in the intraconal area; and malignant lymphoma (40%) and pleomorphic adenoma (24%) in the lacrimal gland area. The age distribution of the 244 patients exhibited two peaks, at 0 to 9 years and 60 to 69 years. In the 0- to 9-year-old patients, the most common tumors were dermoid cyst (26%), optic nerve glioma (11%), capillary hemangioma (11%), and hemorrhagic lymphangioma (11%). On the other hand, in patients over 40 years of age, the common tumors were malignant lymphoma (31%), orbital pseudotumor (24%), pleomorphic adenoma (10%), and cavernous hemangioma (9%). CONCLUSIONS: The pathologic profiles of orbital tumors were characterized according to patient age and the location of the tumor in the orbit. The age of onset, tumor location, and radiological findings provide us with important information for the diagnosis of a tumor prior to biopsy or tumor resection and for the determination of the treatment strategy.

Adolescent↗
PubMedDate not supplied

Effect of high-dose intravenous steroid pulse therapy followed by 3-month oral steroid therapy for Graves' ophthalmopathy.

PURPOSE: To evaluate the effect of high-dose intravenous steroid pulse therapy followed by 3-month oral steroid therapy for Graves' ophthalmopathy. METHODS: We selected 41 Japanese patients (age range, 21-76 years; mean = 49 years) who had active Graves' ophthalmopathy among 205 consecutive patients examined at Sapporo Medical University Hospital between 1997 and 1999. In a prospective study, we investigated the effect on the 41 patients of high-dose intravenous methylprednisolone pulse therapy (1 g/day x 3 days x 3 times) followed by 3-month oral prednisone therapy. Coronal computed tomography (CT) of the orbit, exophthalmometry and monocular fixation field measured by Goldmann perimetry were carried out before the steroid pulse therapy, and 1 and 6 months after the steroid pulse therapy. The maximum coronal section area of the rectus muscle in each eye was measured using an orbital CT image. RESULTS: Extraocular muscle hypertrophy was significantly reduced 1 and 6 months after the pulse therapy (paired t-test, P <.01), and was not significantly different between 1 and 6 months after the pulse therapy. Proptosis was not significantly reduced by the pulse therapy. Monocular fixation fields were measured in 34 patients with diplopia, and limitation of eye movements was improved in 15 patients (44%) by the pulse therapy. In the other patients, improvement of the limitation was not detectable by the test of the monocular fixation field. CONCLUSIONS: The treatment in this study is effective for extraocular muscle hypertrophy, and relapse was minimum within 6 months. However, this treatment has limited effect on limitation of eye movements and less effect on proptosis.

Administration, Oral↗
PubMedDate not supplied

Leaky neural integration observed in square-wave jerks.

PURPOSE: To clarify the neuronal mechanism for the square-wave jerks (SWJs). METHODS: A 66-year-old man presented with oscillatory eye movements. He showed horizontal nystagmus in rightward gaze and SWJs during fixation at straight ahead. We recorded his eye movements with search coil methods and quantitatively analyzed them. RESULTS: Visually guided rightward saccades were followed by exponential drifts with average time constants of 0.3-1.0 second, indicating a leaky rightward velocity-to-position integrator. Amplitude of SWJs ranged from 0.5 to 2.5 degrees and average intersaccadic interval was 0.2 seconds. In addition, exponential drifts similar to those observed after visually guided saccades were observed in the SWJs. Rightward fast eye movements of SWJs were followed by exponential drifts lasting for 0.2 seconds with average time constant (+/-SD) of 0.7+/-0.3 seconds. CONCLUSIONS: Position signals after visually guided saccades and SWJs were outputs of the identical velocity-to-position integrator. SWJs are generated by the neural circuits involving a pulse generator and a velocity-to-position integrator.

Aged↗