Biomedical subjects

Yoshihiro Saito

Publications and source records attributed to Yoshihiro Saito.

At least 19 recordsLinked to original sources

PubMed2006

Simultaneous derivatization/preconcentration of volatile aldehydes with a miniaturized fiber-packed sample preparation device designed for gas chromatographic analysis.

A novel in-needle sample preparation device has been developed for the determination of volatile aldehydes in gaseous samples. The needle device is designed for the gas chromatographic (GC) analysis of aldehydes and ketones commonly found in typical in-house environments. In order to prepare the extraction device, a bundle of polymer-coated filaments was longitudinally packed into a specially designed needle. Derivatization reactions were prompted by 2,4-dinitrophenylhydrazine (NDPH) included in the needle, and so the aldehydes and ketones were derivatized to the corresponding hydrazones and extracted with the extraction needle. A reproducible extraction needle preparation process was established, along with a repeatable derivatization/extraction process that ensures the successful determination of aldehydes. The storage performance of the extraction needle was also evaluated at room temperature for three days. The results demonstrate the successful application of the fiber-packed extraction device to the preparation of a gaseous sample of aldehydes, and the future possibility of applying the extraction device to the analysis of in-house environments.

Journal Article↗

PubMed2006

Multi-institutional analysis of early squamous cell carcinoma of the hypopharynx treated with radical radiotherapy.

PURPOSE: To analyze the outcomes of patients with early hypopharyngeal cancer treated with radical radiotherapy (RT). METHODS AND MATERIALS: Ten institutions combined the data from 115 patients with Stage I-II hypopharyngeal squamous cell carcinoma treated with definitive RT between 1990 and 2001. The median patient age was 67 years; 99 patients were men and 16 were women. Of the 115 patients, 39 had Stage I and 76 had Stage II disease. Conventional fractionation was used in 98 patients and twice-daily RT in 17 patients; chemotherapy was combined with RT in 57 patients. The median follow-up period was 47 months. RESULTS: The overall and disease-specific 5-year survival rate for 95 patients without synchronous malignancies was 66.0% and 77.4%, respectively. The 5-year disease-specific survival rate by T stage was 95.8% for patients with T1 disease and 70.1% for patients with T2 disease (p=0.02). Of the 115 patients, local control with laryngeal voice preservation was achieved in 34 of 39 patients with T1 lesions, including 7 patients successfully salvaged, and in 56 of 76 patients with T2 lesions. Sixty-five patients (56.5%) had synchronous or metachronous cancers. Of the 115 patients, 19 died of hypopharyngeal cancer, 10 died of second primary cancers, and 14 died of other causes during the study and follow-up periods. CONCLUSIONS: Patients with early hypopharyngeal cancer tended to have a good prognosis after RT. However, second malignancies had an adverse effect on the overall outcomes of patients with early hypopharyngeal cancer.

Adult↗

PubMed2006

Isocratic separation of ginsenosides by high-performance liquid chromatography on a diol column at subambient temperatures.

An improved high-performance liquid chromatographic method for separation of a number of ginsenosides has been developed. The influence of temperature (from 0 to 25 degrees C) on the retention and separation of the ginsenosides was studied by applying a binary mobile phase (acetonitrile/water, 82:18 v/v) and a diol column (LiChrospher 100 Diol). The column temperature is one of the more important parameters for the retention and separation of the components investigated. Selected thermodynamic parameters, including changes of enthalpy (deltaH degrees) and entropy (deltaS degrees), were estimated from linear van't Hoff plots, and possible retention mechanisms were discussed. Moreover, the best separation conditions were selected based on optimization criteria including maximum retention time (t(R max)), minimum resolution (R(s min)), and relative resolution product (r). Temperature regions close to 14 degrees C offered the highest selectivity and almost equal distribution of the ginsenosides peaks across the chromatogram. Under such isocratic conditions, excellent separation of chromatographic standards and selected ginseng samples was achieved in less than 16 min.

Chromatography, High Pressure Liquid↗

PubMed2006

Complement factor H polymorphisms in Japanese population with age-related macular degeneration.

PURPOSE: To study the frequency of five haplotypes previously reported in the complement factor H (CFH) gene for Japanese patients with age-related macular degeneration (AMD). METHODS: Genomic DNA was isolated from peripheral blood samples taken from 96 Japanese AMD patients and 89 age-matched controls. All patients were diagnosed as having exudative (wet-type) AMD. The amplified polymerase chain reaction (PCR) products of CFH exons 2, 9, and 13, and intron 6 were analyzed by temperature gradient capillary electrophoresis (TGCE) and by direct sequencing. The haplotypes were identified, and their frequencies were calculated and compared with reported results. RESULTS: Five haplotypes were identified in the Japanese population including four already reported in the American population. The frequencies of these haplotypes were significantly different between Japanese and American in both control and case groups. The haplotype containing Y402H, which was previously reported to be associated with AMD, was only 4% in the control and case population, with a p value of 0.802. However, two other haplotypes were found as risk factors, which gave an increased likelihood of AMD of 1.9 and 2.5 fold (95% CI 1.12-3.69 and 1.42-6.38). One protective haplotype that decreased the likelihood of AMD by 1.6 fold (95% CI 0.26-0.67) was identified. CONCLUSIONS: The frequencies for five haplotypes previously identified were analyzed in a Japanese population with AMD. Four previously found haplotypes were identified and one additional haplotype was found. The frequencies of each haplotype were significantly different from that in found Americans affected with AMD. Two of the haplotypes were identified as risk factors and one was considered protective.

Aged↗

PubMed2006

Visual determination of nitrite and nitrate in waters by color band formation method.

A spot test for aqueous nitrate and nitrite for controlling nitrogen removal performance in small-scale wastewater treatment facilities is proposed. In this method, NO(2)(-) ion in water samples was allowed to react with sulfanilic acid and 1-naphthol to form an anionic azo dye. The resulting colored solution was introduced onto a mini column (similar to a gas detecting tube) packed with PVC particles coated with benzyl cetyl dimethyl ammonium chloride (BCDMA) and biphenyl. The NO(2)(-)-N concentration was determined visually by measuring the color band length (CBL) in the column. The CBL correlates linearly with nitrite concentration in the 4-20 mg-N l(-1) range. The concentration of nitrite+nitrate was determined after reduction to nitrite with zinc. The concentration of NO(3)(-)-N species was calculated by difference. This method was used to visually determine the concentrations of NO(2)(-)-N and (NO(2)(-)+NO(3)(-))-N in domestic wastewater samples with maximum suspended solid (SS) and chemical oxygen demand (COD) concentrations of 114 mg l(-1) and 73.9 mg l(-1), respectively.

Adsorption↗

PubMed2006

Optimization of capillary electrophoretic enantioseparation for basic drugs with native beta-CD as a chiral selector.

This study presents the advantages of the 20 microm inner diameter (id) capillary for the enantioseparation of ten basic drugs with native beta-CD as the chiral selector. The apparent binding constants of each enantiomeric pair were determined to calculate the optimum beta-CD concentration ([beta-CD]opt) and the optimization was subsequently carried out. Comparison of the 20 microm id with 50 microm id were made in terms of the results obtained in the optimization and detection limits. Applying the optimum conditions for each compound, reproducible results (RSD from 0-3; n>5) were obtained for the 20 microm id capillary. Although the sensitivity is lower in the 20 microm id capillary, the LOD determined using this capillary is still found to be acceptable for the ten basic drugs studied. Enhanced resolution and faster analysis times were the main advantages observed with the use of this capillary in enantioseparation.

Adrenergic beta-Agonists↗

PubMed2006

Pars plana vitrectomy and panretinal photocoagulation combined with trabeculectomy for successful treatment of neovascular glaucoma.

BACKGROUND: Treatment of neovascular glaucoma (NVG) must be focused on the reduction of intraocular pressure (IOP) and prompt application of pan retinal photocoagulation (PRP). A combination of complete PRP during vitrectomy with trabeculectomy should theoretically be a better method to lower the IOP rapidly in eyes with NVG. The purpose of our study is to assess the efficacy of combining pars plana vitrectomy and PRP with trabeculectomy assisted by mitomycin C (MMC) on NVG eyes secondary to diabetic retinopathy. METHODS: Twenty-five eyes with NVG associated with diabetic retinopathy had pars plana vitrectomy, followed by PRP and trabeculectomy with MMC. The eyes were divided into two groups: nine eyes with vitreous hemorrhage, fibrovascular membrane and/ or retinal detachment were placed in the Proliferation group; and 16 eyes without vitreous hemorrhage, fibrovascular membrane, or retinal detachment were placed in the PC (photocoagulation) group. These eyes had vitrectomy performed so that PRP could be safely performed from ora to ora. The surgical outcome in the two groups was assessed by Kaplan-Meier survival analysis. The criteria for success were a postoperative intraocular pressure (IOP) < or =21 mmHg and a preservation of light perception. RESULTS: In the Proliferation group, Kaplan-Meier life-table analysis showed that the success rate was 55.6% after 1 year and 18.5% after 2 years. The success rate in the PC group was 81.2% from 1 to 3 years after surgery. The surgical outcome was significantly better in the PC group than in the Proliferation group (P=0.009). In the Proliferation group, four eyes had preoperative vitreous hemorrhage, three eyes had a fibrovascular membrane, and two eyes had a retinal detachment. Three of four eyes with vitreous hemorrhage achieved good IOP control. On the other hand, the IOP of all eyes with retinal detachment and fibrovascular membrane were not lowered significantly. CONCLUSIONS: Complete PRP combined with trabeculectomy with MMC can effectively reduce the elevated IOP in eyes with NVG. However, this combined treatment is not effective in eyes with proliferative membranes and retinal detachments.

Adult↗

PubMed2006

Preoperative cardiac evaluation: when should the surgeon consult the cardiologist?

PURPOSE: We compiled a manual aimed at reducing preoperative cardiac assessment costs and defining the roles of surgeons and cardiologists. We tested prospectively and retrospectively if this manual achieved these goals. METHODS: Using the Guidelines for Perioperative Cardiovascular Evaluation for Noncardiac Surgery of the American College of Cardiology (ACC) / American Heart Association (AHA), and other articles as a reference, we compiled the Jichi Medical School Hospital (JMSH) Manual in September 2002. This manual contains a novel checklist and flowcharts and includes all past and present cardiac disorders, complications, abnormalities in electrocardiograms (ECGs) and chest X-rays, and evaluation of daily activity. Using this manual, we prospectively studied 1087 surgical candidates from September 2002 to August 2003, and retrospectively analyzed 927 surgical candidates from September 2001 to August 2002. RESULTS: In the prospective study, 39 (3.6%) patients were deemed to require further cardiac assessment and 4 (0.37%) suffered postoperative complications. In the retrospective study, 108 (11.7%) were deemed to require further cardiac assessment and 20 (2.2%) suffered postoperative complications. Using this manual reduced preoperative cardiac examination costs by 1323,600 Japanese yen, representing a 70.5% reduction. CONCLUSIONS: The JMSH Manual defines the roles of surgeons and cardiologists and is useful for assessing preoperative cardiac function and surgical risks. This manual dramatically reduced the costs associated with preoperative cardiac examinations.

Cardiology↗

PubMed2006

A major urinary protein of the domestic cat regulates the production of felinine, a putative pheromone precursor.

Domestic cats spray urine with species-specific odor for territorial marking. Felinine (2-amino-7-hydroxy-5,5-dimethyl-4-thiaheptanoic acid), a putative pheromone precursor, is excreted in cat urine. Here, we report that cauxin, a carboxylesterase excreted as a major urinary component, regulates felinine production. In vitro enzyme assays indicated that cauxin hydrolyzed the felinine precursor 3-methylbutanol-cysteinylglycine to felinine and glycine. Cauxin and felinine were excreted age dependently after 3 months of age. The age-dependent increases in cauxin and felinine excretion were significantly correlated. In mature cats, cauxin and felinine levels were sex-dependently correlated and were higher in males than in females. In headspace gas of cat urine, 3-mercapto-3-methyl-1-butanol, 3-mercapto-3-methylbutyl formate, 3-methyl-3-methylthio-1-butanol, and 3-methyl-3-(2-methyldisulfanyl)-1-butanol were identified as candidates for felinine derivatives. These findings demonstrate that cauxin-dependent felinine production is a cat-specific metabolic pathway, and they provide information for the biosynthetic mechanisms of species-specific molecules in mammals.

Animals↗

PubMed2006

Radiation therapy alone for stage I (UICC T1N0M0) squamous cell carcinoma of the esophagus: indications for surgery or combined chemoradiotherapy.

BACKGROUND AND AIM: The aim of this study was to clarify the efficacy and limitations of radiation therapy (RT) for superficial esophageal carcinoma, and to explore the indications for more aggressive therapy, such as combined chemo-radiotherapy. METHODS: Sixty-eight patients with stage I (UICC T1N0M0) esophageal squamous cell carcinoma treated by definitive RT alone were analyzed. Brachytherapy was administered in 36 patients as a boost, and the prescribed doses were 10 Gy (5 Gy x 2 times) at a low dose rate (19 patients) and 9 Gy (3 Gy x 3 times) at a high dose rate (17 patients). Recurrence patterns and survival rates were assessed and the factors predisposing to recurrences after RT were statistically investigated by univariate analysis. RESULTS: The 5-year cause-specific survival rate and the locoregional control rate were 79.9% and 82.1%, respectively. No case of recurrence or disease-related death was observed in any of the patients with mucosal cancer. Among the cases with the cancer invading the submucosa, there were 12 cases with locoregional recurrence and two cases with distant metastases. In cases of submucosal esophageal cancer, the tumor length was the only statistically significant factor predicting locoregional control. The 5-year locoregional control rate in cases with a short length of the tumor ( 5 cm in length was 57.8% (P = 0.036). Patients treated by additional brachytherapy exhibited better cause-specific survival and locoregional control rates than those receiving external RT alone, however, the addition had no statistically significant influence on the outcome. CONCLUSIONS: RT was a successful treatment for stage I esophageal cancer, and the treatment outcome using RT was nearly comparable to that of surgery. However, it is suggested that chemo-radiation should be considered in inoperable cases of submucosal cancer when the tumor is more than 5 cm in length.

Aged↗

PubMed2006

Trabeculectomy with mitomycin C for treatment of neovascular glaucoma in diabetic patients.

BACKGROUND: To assess the efficacy and to determine the risk factors of trabeculectomy with mitomycin C (MMC) in eyes with neovascular glaucoma (NVG) secondary to diabetic retinopathy. METHODS: Kaplan-Meier survival analysis of the surgical outcome was performed on 35 eyes with NVG. Age, extent of peripheral anterior synechia, surgical history (cataract, glaucoma, vitrectomy), and concurrent retinal cryotherapy were evaluated to determine factors influencing the surgical outcome. The main criterion for success was a postoperative intraocular pressure (IOP) of < or = 21 mm Hg. RESULTS: The cumulative probability of success was 67.0% at 1 year and 61.8% after 2 to 3 years. The surgical outcome was significantly better in patients without a previous vitrectomy (p = 0.03). Extensive preoperative peripheral anterior synechia was also a risk factor for surgical failure (p = 0.013). CONCLUSIONS: Trabeculectomy with MMC can effectively reduce the elevated IOP associated with NVG. The extent of peripheral anterior synechia and a history of vitrectomy are significant negative predictors of surgical outcome.

Adult↗

PubMed2006

Calorimetry and cryo-transmission electron microscopic studies of PEG2000-grafted liposomes.

The phase behavior of poly(ethylene glycol) grafted liposomes (PEG-liposomes) was investigated by differential scanning calorimetry (DSC), dynamic light scattering (DLS) and cryo-transmission electron microscopy (cryo-TEM). PEG-liposomes were prepared from mixtures of dipalmitoyl phosphatidylcholine (DPPC) and distearoyl phosphatidylethanolamine with a covalently attached PEG molecular weight of 2000 (DSPE-PEG2000). From the results of DLS measurements, the coexistence of PEG-liposomes and small molecular assemblies were confirmed at mole fractions of DSPE-PEG2000 above about 0.1. Moreover, it was confirmed that small molecular assemblies were disk micelles by cryo-TEM. However, the phase transition enthalpies of PEG-liposomes were hardly changed according to the DSC measurement, though the mole fraction of the PEG lipid increased. From these results, it was suggested that the phase transition enthalpies hardly changed despite mixed micelles being formed because the bilayer structure of the disk micelle maintains high cooperativity between the DPPC molecules.

1,2-Dipalmitoylphosphatidylcholine↗

PubMed2006

Carboxyfluorescein leakage from poly(ethylene glycol)-grafted liposomes induced by the interaction with serum.

The effects of fetal bovine serum (FBS) on carboxyfluorescein (CF) leakage from poly(ethylene glycol)-grafted liposomes (PEG-liposomes) were investigated. PEG-liposomes were prepared from dipalmitoylphosphatidylcholine (DPPC) and distearoyl-N-monomethoxy poly(ethylene glycol)-succinyl-phosphatidylethanolamines (DSPE-PEG) having PEG molecular weights of 1000, 2000, 3000 and 5000. The presence of FBS dramatically increased CF leakage from liposomes near the gel-liquid crystalline phase transition temperature, but had little effect at lower and higher temperatures. The CF leakage from PEG-liposomes whose molecular weight in PEG units was above 2000 was suppressed compared with that of liposomes without PEG. And, there was hardly any difference in the effect of the PEG molecular weight of the PEG-lipids on CF leakage from PEG-liposomes with FBS when PEG-lipids with a molecular weight in PEG units above 2000 were used. On the other hand, the leakage of CF from liposomes containing 0.145 mol fractions of DSPE-PEG1000 was larger than that of liposomes without PEG. Furthermore, the effects of FBS on the cooperative units of lipid molecules during the gel-liquid crystalline phase transition of liposomes were examined. However, the cooperative units of liposomes with FBS had little change compared with that of liposomes without FBS.

Calorimetry, Differential Scanning↗

PubMed2006

[Calcification on the posterior surface of an implanted silicone intraocular lens in a patient with asteroid hyalosis].

BACKGROUND: Calcification on the surface of the hydrogel intraocular lens (IOL) has been reported, but the mechanism of the surface calcification is not fully understood. We report a case of surface calcification on an implanted silicone IOL. The purpose of our study was to examine the clinical and ultrastructural findings associated with the late surface calcification of a silicone IOL. CASE: A 70-year-old Japanese man had undergone cataract surgery in his left eye, with uneventful phacoemulsification and silicone IOL (Allergan SI-55 NB) implantation with the manufacturer's cartridge and injector. He was referred again 29 months later with blurred vision, glare sensitivity, and decreased vision in his left eye. He was diagnosed as having aftercataract. Although YAG laser capsulotomy was performed, the opacity on the posterior surface gradually increased. The opacity was located mainly within the capsulotomy window on the posterior surface of the lens, although the patient maintained good visual acuity. LV : 0.2 (1.0 x S-2.0 D). The lens was removed 46 months after the initial surgery. Scanning electron microscopy (SEM) showed membranous deposits on the posterior optical surface of the silicone lens. There were high levels of phosphoric acid (P) and calcium (C) confirming calcification of the silicone IOL. Asteroid hyalosis was observed in the fellow eye of the patient. CONCLUSION: This is the first report of surface calcification of a silicone IOL in Japan. Although the mechanism of the calcification has not been determined, careful clinical follow-up of patients implanted with silicone lenses is necessary to determine if this phenomenon is rare and sporadic or if it may be more widespread. Since 5 similar cases of calcification in silicone lenses with accompanying asteroid hyalosis have been reported in other countries, we can conclude that silicone lens implantation in eyes with asteroid hyalosis should be avoided.

Aged↗

PubMed2005

In-needle extraction device designed for gas chromatographic analysis of volatile organic compounds.

A novel in-needle extraction device has been developed for the preconcentration of gaseous organic compounds prior to the determination in gas chromatography (GC). As the extraction medium, a copolymer of methacrylic acid and ethylene glycol dimethacrylate was synthesized. Based on the results in the preliminary experiments, the desorption conditions such as desorption temperature and time have been optimized along with the evaluation of the extraction efficiency. The storage performance of the needle extraction device was also studied. The results clearly demonstrated the excellent extraction performance for typical organic solvents and also suggested the future possibility such as in the applications for the analysis of working environments.

Chromatography, Gas↗

PubMed2005

High-temperature separation with polymer-coated fiber in packed capillary gas chromatography.

High-temperature gas chromatographic separation of several synthetic polymer mixtures with Dexsil-coated fiber-packed columns was studied. A bundle of heat-resistant filaments, Zylon, was longitudinally packed into a short metal capillary, followed by the conventional coating process with Dexsil 300 material. Prior to the packing process the metal capillary was deactivated by the formation of a silica layer. The typical size of the resulting column was 0.3-mm i.d., 0.5-mm o.d., 1-m length, and packed with about 170 filaments of the Dexsil-coated Zylon. The column temperature could be elevated up to 450 degrees C owing to the good thermal stability of the fiber, Dexsil coating, and metal capillary; furthermore, this allowed the separation of low-volatile compounds to be studied.

Chromatography, Gas↗

PubMed2005

Surface derivatization of poly(p-phenylene terephthalamide) fiber designed for novel separation and extraction media.

The surface derivatization of poly(p-phenylene terephthalamide) fiber was studied. The obtained surface-derivatized filaments were packed into a fused-silica capillary to evaluate its surface characteristics by using GC. As the stationary phase for GC the surface-derivatized fibers showed higher retention for alkanes and alkylbenzenes than that with the untreated Kevlar fiber. The improvements on the retention power and the peak shape were observed on the benzyl-modified fibrous stationary phase. The derivatized fibrous materials were also evaluated as the extraction medium in fiber-in-tube SPE, and the effect of the surface modification on the extraction power was compared to the parent fiber. The results indicated that the modified fiber possessed a higher extraction power than the untreated fiber. Based on the facts, the successful modification of the fiber surface was estimated.

Journal Article↗

PubMed2005

Nonvitrectomizing vitreous surgery for epiretinal membrane long-term follow-up.

PURPOSE: To report the long-term follow-up results of nonvitrectomizing vitreous surgery for idiopathic epiretinal membrane (ERM). DESIGN: Nonrandomized comparative case series. PARTICIPANTS: Thirty patients were followed up for at least 5 years after nonvitrectomizing vitreous surgery. INTERVENTION: Epiretinal membranes were peeled without infusion of balanced salt solution and removal of the vitreous. The data from the fellow eye was the control data. MAIN OUTCOME MEASURES: We examined the visual acuities (VAs), objective refractions, and slit-lamp and Scheimpflug photographs from the preoperative and the final examinations of both eyes. Quantitative assessment of the progression of nuclear sclerosis was performed by densitometry analysis using Scheimpflug photography. The recurrence rate of ERM was determined. RESULTS: The follow-up periods ranged from 60 to 102 months (mean+/-standard deviation, 72.2+/-11.0 months). The patient ages ranged from 52 to 76 years (68.8+/-6.3 years). The final VA improved or stabilized within 2 lines in 29 of 30 eyes (96.7%). No unilateral progression of nuclear sclerosis occurred in any cases. The mean preoperative and postoperative refractions without additional surgery were -0.4+/-2.9 diopters (D) and -0.2+/-3.0 D in the operated eyes, respectively, and -0.2+/-2.5 D and 0.1+/-2.4 D, respectively, in the unoperated fellow eyes. The mean differences in the refractive error between both eyes (operated eye data minus fellow eye data) were -0.2+/-0.7 D before surgery and -0.3+/-0.8 D after surgery (P = 0.319, paired t test). The mean preoperative and postoperative nuclear densities in 16 patients were 69+/-14 nuclear density units (NDUs) and 76+/-12 NDUs in the operated eyes and 71+/-14 NDUs and 78+/-14 NDUs in the fellow eyes, respectively. The mean preoperative and postoperative differences in nuclear densities in both eyes were -2+/-2 NDUs and -2+/-5 NDUs, respectively (P = 0.836, paired t test). The ERM recurred in 10 eyes (33%), and 3 eyes underwent conventional vitrectomy combined with cataract surgery. CONCLUSIONS: Unilateral nuclear sclerosis did not progress for at least 5 years after nonvitrectomizing vitreous surgery. The recurrence rate of ERM appeared to be higher than that after conventional vitreous surgery.

Aged↗