Biomedical subjects

Yoshiyuki Kawashima

Publications and source records attributed to Yoshiyuki Kawashima.

15 recordsLinked to original sources

PubMed2006

Rotational spectrum and inversion motions in the neon-dimethyl sulfide complex.

The rotational spectra of the (20)Ne and (22)Ne isotopomers of the Ne-dimethyl sulfide (DMS) rare gas dimer have been measured by Fourier transform microwave spectroscopy. MP2/6-311++G(2d,2p) calculations, and the experimental spectroscopic data, suggest a structure of C(s) symmetry in which the Ne atom lies above the heavy atom plane of the DMS (in the sigma(v) plane which bisects the CSC angle). Experimental rotational constants are consistent with a S...Ne distance of 3.943(6) Angstroms and a (cm...S...Ne) angle of 63.2(6) degrees (where cm is the center of mass of DMS). A motion of the Ne atom from one side of the DMS to the other gives rise to inversion splittings of around 3 MHz in the c-type transitions. An ab initio potential energy surface calculation has allowed examination of several possible tunneling pathways, and suggests a barrier of between 20 and 40 cm(-1) for the inversion motion, depending on the tunneling pathway taken by the Ne. Dipole moment measurements are consistent with both the experimental and ab initio structures.

Journal Article↗

PubMed2006

Internal motions in a complex consisting of a rare gas atom and a C2v molecule: theoretical formulations and their applications to Fourier transform microwave spectra of Ne-dimethyl ether and Ar-dimethyl ether.

The internal motion of the rare gas atom, i.e., the relative motion of the two constituents, in a complex shown in the title was discussed by paying special attention to its effect on the rotational motion of the complex in order to extract as much precise information on this motion as possible from the observed rotational spectra. We have set up two theoretical formulations. One is based on a coordinate axis system attached to the C2v molecule, but its origin is floating with the motion of the rare gas atom, while keeping the orientation parallel to the original C2v molecule-fixed coordinate system. The second approach starts with counting the number of equivalent potential minima, which are well separated from the others by high potential barriers, and then collects all permutation-inversion operations, which transform the system from one minimum to another, to set up a group appropriate for the complex. By using the symmetry properties thus derived, a phenomenological Hamiltonian is set up to fit the observed spectra. The two formulations result in alike rotational energy matrices, and we have applied them to analyze the internal motions in the two complexes of present concern: neon-dimethyl ether (Ne-DME) and argon-dimethyl ether (Ar-DME). Some of the transitions observed by the present study exhibited additional splittings, which were interpreted as due to an internal rotation of the methyl groups in DME and were analyzed by the second formulation. For Ar-DME the splittings appeared only in high-K transitions, yielding the V3 potential barrier to be 778(1) cm(-1), whereas those observed for Ne-DME were ascribed to the effects of the CH3 internal rotation on the inversion splitting.

Journal Article↗

PubMed2006

Dynamical structure of peptide molecules.

In view of the importance of the peptide linkage in structural biology, we have carried out intensive investigations on peptide molecules consisting of a peptide linkage with one or two substituents in the gas phase by Fourier transform microwave spectroscopy, paying special attention to the internal rotation of the substituents relative to the central linkage framework. We have found that, in sharp contrast with the stiff structure around the central C-N bond of the linkage, the internal rotations of the substituents are of low frequency and thus of large amplitude and are extremely susceptible to their local environment such as the presence of other substituents.

Peptides↗

PubMed2005

An autosomal dominant cerebellar ataxia linked to chromosome 16q22.1 is associated with a single-nucleotide substitution in the 5' untranslated region of the gene encoding a protein with spectrin repeat and Rho guanine-nucleotide exchange-factor domains.

Autosomal dominant cerebellar ataxia (ADCA) is a group of heterogeneous neurodegenerative disorders. By positional cloning, we have identified the gene strongly associated with a form of degenerative ataxia (chromosome 16q22.1-linked ADCA) that clinically shows progressive pure cerebellar ataxia. Detailed examination by use of audiogram suggested that sensorineural hearing impairment may be associated with ataxia in our families. After restricting the candidate region in chromosome 16q22.1 by haplotype analysis, we found that all patients from 52 unrelated Japanese families harbor a heterozygous C-->T single-nucleotide substitution, 16 nt upstream of the putative translation initiation site of the gene for a hypothetical protein DKFZP434I216, which we have called "puratrophin-1" (Purkinje cell atrophy associated protein-1). The full-length puratrophin-1 mRNA had an open reading frame of 3,576 nt, predicted to contain important domains, including the spectrin repeat and the guanine-nucleotide exchange factor (GEF) for Rho GTPases, followed by the Dbl-homologous domain, which indicates the role of puratrophin-1 in intracellular signaling and actin dynamics at the Golgi apparatus. Puratrophin-1--normally expressed in a wide range of cells, including epithelial hair cells in the cochlea--was aggregated in Purkinje cells of the chromosome 16q22.1-linked ADCA brains. Consistent with the protein prediction data of puratrophin-1, the Golgi-apparatus membrane protein and spectrin also formed aggregates in Purkinje cells. The present study highlights the importance of the 5' untranslated region (UTR) in identification of genes of human disease, suggests that a single-nucleotide substitution in the 5' UTR could be associated with protein aggregation, and indicates that the GEF protein is associated with cerebellar degeneration in humans.

5' Untranslated Regions↗

PubMed2005

Epidemiological study of mumps deafness in Japan.

In Japan, mumps vaccination is optional and the mumps were increased accompanied with prevalent waves according to the Infections Agents Surveillance Report (IASR). The aim of this study was to clarify that there was relevance for increase of mumps epidemic and mumps deafness. The Acute Profound Deafness Research Committee of the Japanese Ministry of Health and Welfare (reorganized to the Ministry of Health, Labour and Welfare in 2001) conducted a nationwide epidemiological survey to determine the number of patients treated for mumps deafness in 1987, 1993 and 2001. Based on its findings, the annual numbers of mumps deafness cases was estimated to be 300 in 1987, 400 in 1993 and 650 in 2001, which correlated with the overall incidence of mumps in those years. Because the majority of cases exhibited severe or profound sensorineural hearing loss that usually did not recover, rapid improvement of mumps vaccine coverage is strongly recommended.

Child↗

PubMed2005

Idiopathic ulcer of the small bowel containing numerous plasma cells: case resembling mucosa-associated lymphoid tissue lymphoma.

Idiopathic ulcer of the small bowel is a poorly recognized entity. Herein is reported a case of idiopathic ulcer of the jejunum containing numerous lymphoplasmacytoid infiltrates and mimicking mucosa-associated lymphoid tissue (MALT) lymphoma. An 82-year-old Japanese woman presented with nausea and vomiting. Following diagnosis of submucosal tumor, partial jejunal resection was performed. Macroscopically the resected specimen contained multiple small shallow ulcers. Histologically the lesion was composed of numerous plasma cells mixed with lymphocytes and histiocytes. Immunohistological study revealed that the plasma cells contained polytypic intracytoplasmic immunoglobulins. The patient remained free of disease after 36 months. Marginal zone B-cell lymphoma of MALT-type arising from small intestine occasionally shows prominent plasma cell differentiation. The present case demonstrates that idiopathic ulcer of the small bowel should be added to the differential diagnosis of MALT-type lymphoma of the small bowel.

Aged↗

PubMed2004

Comparison of acute low-tone sensorineural hearing loss versus Meniere's disease by electrocochleography.

To clarify the pathogenesis of acute low-tone sensorineural hearing loss (ALHL), we retrospectively compared the electrocochleographic findings from 20 patients with ALHL with those from 58 patients with Meniere's disease (MD) classified into 4 groups (MD1 through MD4) according to their pure tone average. The mean summating potential-action potential ratio in the ALHL group was 0.35 +/- 0.13, which was significantly higher than the control ratio but similar to the ratio seen in the MD1 group (pure tone average < 25 dB hearing level). The mean detection threshold of the cochlear microphonics in the ALHL group was 32.0 +/- 9.4 dB normal hearing level, which was again similar to that seen in the MDI group. Moreover, more than 50% of patients with ALHL had normal cochlear microphonics input-output curves. We therefore conclude that the pathogenesis of ALHL arises from an endolymphatic hydrops with little or no impairment of hair cells that resembles early-stage MD.

Action Potentials↗

PubMed2004

[Investigation of automated infant auditory screening using the Natus-ALGO Portable device].

The aim of this study was to compare the Natus-ALGO Portable (Portable) device with the Natus-ALGO 2e and to evaluate its usefulness. Portable, an automated ABR screener (Natus Medical, Foster City, CA, USA) was used to screen 826 neonates in our hospital between February 2002 and March 2003. The referral rate for the first automated ABR screening was 0.85% while that for the second was 0.48%. Hearing impairment was detected in 0.24% of all newborns. The mean duration of the automated ABR test was 2 minutes, 45 seconds. The referral rate and mean test duration of the Portable device was equivalent to that of the Natus-ALGO 2e. We concluded that the Portable device is a useful tool in view of its low cost and portability. Among those who passed the Portable screening, the number of sweeps in the neonatal intensive care unit was significantly greater than that in the maternity ward. Careful estimation of REFER in neonatal intensive care units is important because the incidence of positive fails in the neonatal intensive care unit was much higher than that in the maternity ward. The number of sweeps performed in neonates between the ages of 2 to 6 days was not significantly different.

Hearing Tests↗

PubMed2003

Adjuvant therapy with protein-bound polysaccharide K and tegafur uracil in patients with stage II or III colorectal cancer: randomized, controlled trial.

PURPOSE: Intravenous fluorouracil and leucovorin for six to eight months is currently a standard adjuvant treatment for Stage III colon cancer; however, this regimen is complex, inconvenient, and has a high intolerability. Adjuvant chemotherapies are claimed for objective response rates with an acceptable safety profile and complexity. We investigated the benefits of oral protein-bound polysaccharide K added to oral tegafur/uracil on curatively resected Stage II or III colorectal cancer. METHODS: We prospectively randomized 207 patients to treatments of either oral 3.0 g protein-bound polysaccharide K plus 300 mg tegafur/uracil or 300 mg tegafur/uracil alone for two years following 12 mg/m2 and 8 mg/m2 mitomycin treatment on postoperative Days 1 and 2, respectively. The primary end points were disease-free and overall survival, and recurrence rates. RESULTS: Three (1.4 percent) patients were declared ineligible, and three patients did not start treatment. In total, 201 patients were analyzed. The three-year, disease-free survival rate was 80.6 percent (standard error = 3.4 percent) in the protein-bound polysaccharide K group (P = 0.02) compared with 68.7 percent (SE = 5.7 percent) in the control group after a median follow-up of 3.7 years. The estimated relative risk of recurrence in the control group was 1.87 (95 percent confidence interval, 1.10-3.20) at three years. The three-year, overall survival rate was 87.3 percent (standard error = 2.9 percent) in the protein-bound polysaccharide K group and 80.6 percent (standard error = 4.8 percent) in the control group (P = 0.24). The three-year, overall survival rate in 80 pathological TNM Stage III patients was 83.0 percent (standard error = 5.2 percent) in the protein-bound polysaccharide K group and 59.3 percent (standard error = 9.5 percent) in the control group (P = 0.02). Protein-bound polysaccharide K prevented distant metastases (P = 0.05), particularly lung metastases (P = 0.01). The incidence of adverse effects was minimal, and compliance was good. CONCLUSION: Adjuvant therapy using a combination of oral protein-bound polysaccharide K and tegafur/uracil is highly effective in preventing the recurrence of colorectal cancer in Stage II or III patients, and increases overall survival in pathological TNM Stage III. These results will be a sufficient proof to conduct a larger study to compare tegafur/uracil/protein-bound polysaccharide K with 5-fluorouracil/leucovorin.

Adult↗

PubMed2002

Ileal perforation caused by cytomegalovirus infection in a patient with recurrent gastric cancer: report of a case.

We report a case of ileal perforation caused by cytomegalovirus (CMV) infection in a patient with peritoneal recurrence of gastric cancer. Emergency laparotomy revealed a pinhole-sized perforation in a reddish segment of the small bowel, 100 cm proximal to the terminal ileum, and peritoneal carcinosis of recurrent gastric cancer invading the transverse colon and the gastrojejunal anastomosis of a Billroth-II procedure. The affected ileum was resected, a primary anastomosis was performed, and a colostomy was made in the ascending colon. The histology of the ileum revealed acute inflammation with vasculitis and CMV inclusions in the macrophages and endothelial cells and evidence of CMV on immunostaining. There was no evidence of cancer cell invasion or any other pathogens. Although the prognosis associated with bowel perforation due to CMV infection is poor, emergency surgery saved our patient's life.

Cytomegalovirus Infections↗

PubMed2002

A case of myoepithelioma arising in an accessory parotid gland.

The present paper describes the first reported case, to our knowledge, of a myoepithelioma arising in an accessory parotid gland. Because pre-operative fine-needle aspiration cytological findings and operative findings suggested that this tumour was malignant, the decision was made to remove the tumour surgically along with the buccal branches of the facial nerve. The resected nerve was reconstructed by nerve transplantation, using the great auricular nerve. Subsequently the tumour was found to be benign. One year after surgery, the patient had excellent facial nerve function and so far there has been no evidence of recurrence.

Adult↗

PubMed2001

Internal Rotation of the Hydroxyl Group in Isopropanol and the Chirality of the Gauche Form: Fourier Transform Microwave Spectroscopy of (CH(3))(2)CHOD.

The rotational spectrum of the deuterated isopropanol (CH(3))(2)CHOD has been observed by Fourier transform microwave spectroscopy and analyzed to yield tunneling splitting of 4431.4613 (17) MHz, between the antisymmetric and the symmetric gauche forms, which is much larger than the 2400 MHz estimated from the internal-rotation potential function reported in the literature. The potential function for the OH internal rotation has been examined in view of the discrepancy between the observed and estimated tunneling splitting, and it was accounted for by taking into account isotope effects on the potential constants. The deuterium quadrupole coupling effect has been included together with the Coriolis terms in the off-diagonal block of the Hamiltonian matrix for the gauche form. The deuterium quadrupole coupling constants obtained for the trans form were employed to calculate the components of the coupling constants as functions of the internal-rotation angle, and the components at around 120 degrees were compared with the values observed for the gauche form, thereby leading to unambiguous determination of the signs of the constants in the off-diagonal block; the signs are not obtainable from an ordinary analysis of the rotational spectra. The chirality of the gauche form was discussed by placing special emphasis on the effect of intermolecular interactions between two chiral molecules. Copyright 2001 Academic Press.

Journal Article↗

PubMed2001

FR128998 (a PAF Receptor Antagonist) Counters the Increased Pulmonary Vascular Resistance Associated with Ischemia-Reperfusion Injury in the Canine Lung.

Ischemia-reperfusion injury induces deterioration of pulmonary function following lung transplantation. The spiro-thiazepin derivative FR128998 (FR) is a novel PAF receptor antagonist. The effect of FR on ischemia-reperfusion injury was investigated in an in situ warm ischemia model of canine lungs. Fifteen adult mongrel dogs, weighing 6 to 12 kg, were divided into two groups. FR (1 mg/kg/hr) was administered from prior to ischemia until 2 hours after reperfusion (FR-treated group; n = 8), or vehicle was injected using the same technique (Control group; n = 7). Following hilar stripping of the left lung, the left pulmonary artery and veins were clamped for 3 hours to induce warm ischemia. The left main bronchus was bisected at the same time and anastomosed 3 hours later. Arterial oxygen saturation (SaO(2)), left pulmonary vascular resistance (L-PVR), and cardiac output (CO) were measured 30 minutes after reperfusion. The lungs were harvested for pathological study, and polymorphonuclear neutrophils (PMNs) were counted. The 2-day survival rate was also investigated. After reperfusion, SaO(2) L-PVR, and CO were significantly (p < 0.05) better in the FR-treated group than in the control group. Histological findings after 30 minutes of reperfusion showed alveolar damage with interstitial edema and hyaline membranes localized along the alveolar ducts in the control group, while there was only slight localized interstitial edema in the FR group. PMN infiltration was less extensive in the FR group than in the control group. FR appears to have a protective effect against lung ischemia-reperfusion injury. This might result from inhibition of the local release of PAF. </hea

Journal Article↗

PubMedDate not supplied

Intraoperative massive pulmonary tumor embolism from clear cell sarcoma in the retroperitoneum: successful treatment using cardiopulmonary bypass.

Malignant neoplasms rarely extend into the inferior vena cava and up to the right side of the heart. Although massive pulmonary tumor embolism occurs relatively rarely, it can be a catastrophic problem. Intraoperative pulmonary tumor embolism and cardiac arrest occurred in a 68-year-old woman while dissecting the inferior vena cava to resect a pararenal tumor extending into the retrohepatic inferior vena cava. Abrupt arterial hypotension, tachycardia, and increased central venous pressure lead to the diagnosis of massive pulmonary tumor embolism. Emergency cardiopulmonary bypass was commenced under profound hypothermia and cardiac arrest. The tumors in the main pulmonary artery were extracted, and fragments of remnant tumor were retrieved by a vascular endoscope, a Fogarty catheter, and milking of the lung. Following embolectomy, the tumor in the retrohepatic to infrarenal inferior vena cava was removed and the primary tumor together with the infrarenal inferior vena cava was resected under hepatic vascular exclusion and partial cardiopulmonary bypass. The inferior vena cava below the renal veins was not reconstructed. The patient recovered with slight retrograde amnesia. A postoperative pulmonary perfusion scintigram showed no defect in the pulmonary circulation. She is well now 8 months after surgery. Safe prevention measures should be accomplished as a part of the perioperative management of patients with inferior vena cava tumor thrombus that may be fragile, and cardiopulmonary bypass should always be stand-by on surgery.

Aged↗

PubMedDate not supplied

A combination phase I study of weekly paclitaxel and doxifluridine in advanced gastric cancer patients.

BACKGROUND: Preclinical studies have shown that paclitaxel and doxifluridine can act synergistically without overlapping toxicity for the treatment of advanced gastric cancer. The objectives of this study were to determine the maximum tolerated dose (MTD), the dose-limiting toxicity and the recommended Phase II dose for this drug combination. PATIENTS AND METHODS: Patients with histologically confirmed gastric cancer were eligible for the study. The paclitaxel dose (days 1, 8, 15) was augmented with a fixed dose of for treatments (1-3). doxifluridine (533 mg/m2, 5 days/week) on a 28-day cycle. RESULTS: Eighteen patients were enrolled. The MTD was not reached until the highest dose level. One patient had Grade 3 myelosuppression. The responses of the 13 suitable patients included 1 complete response and 5 partial responses. CONCLUSION: Although the MTD level could not be definitively which is a established, upon consideration of the lengthy administration time and the effectiveness, the recommended Phase II dose of paclitaxel was concluded to be 80 mg/m2 in combination with doxifluridine at 533 mg/m2.

Aged↗