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Biomedical subjects

H Katsura

Publications and source records attributed to H Katsura.

At least 19 recordsLinked to original sources
PubMed2005

The effect of site and type of nerve injury on the expression of brain-derived neurotrophic factor in the dorsal root ganglion and on neuropathic pain behavior.

A number of rat neuropathy models have been developed to simulate human neuropathic pain conditions, such as spontaneous pain, hyperalgesia, and allodynia. In the present study, to determine the relative importance of injury site (proximal or distal to the primary afferent neurons) and injury type (motor or sensory), we examined pain-related behaviors and changes of brain-derived neurotrophic factor expression in the dorsal root ganglion in sham-operated rats, and in the L5 dorsal rhizotomy, L5 ventral rhizotomy, L5 dorsal rhizotomy+ventral rhizotomy, and L5 spinal nerve transection models. L5 ventral rhizotomy and spinal nerve transection produced not only mechanical and heat hypersensitivity, but also an increase in brain-derived neurotrophic factor mRNA/protein in the L5 dorsal root ganglion at 7 days after surgery. In contrast, rats in the L5 dorsal rhizotomy and dorsal rhizotomy+ventral rhizotomy groups did not show both pain behaviors at 7 days after surgery, despite brain-derived neurotrophic factor upregulation in medium- and large-size neurons in the L5 dorsal root ganglion. On the other hand, L5 spinal nerve transection, but not dorsal rhizotomy, dorsal rhizotomy+ventral rhizotomy or ventral rhizotomy, increased the expression of brain-derived neurotrophic factor in the L4 dorsal root ganglion at 7 days after surgery. Taken together, these findings suggest that the upregulation of brain-derived neurotrophic factor expression in the L4 and L5 dorsal root ganglion neurons may be, at least in part, involved in the pathophysiological mechanisms of neuropathic pain and that the selective nerve root injury models may be useful for studying the underlying mechanisms of chronic pain after nerve injury.

Animals↗
PubMed2001

Microcirculation in the macular area of eyes with an idiopathic epiretinal membrane.

PURPOSE: To measure the microcirculation in the macula area of eyes before and after the removal of an idiopathic epiretinal membrane (ERM) by vitreous surgery. METHODS: Tissue blood flow in the macula was examined with the Heidelberg retina flowmeter in 12 eyes with an ERM before and 3, 6, and 12 months after vitrectomy. Blood flow measurements were performed in a 10 x 5 degree area in the macula that was divided into superior and inferior areas. At least three measurements were obtained, and the mean blood flow (MBF) was calculated by scanning laser Doppler flowmetry. The ratio of the MBF in the affected eye to that in the fellow eye was used for statistical analysis. RESULTS: The ratios of the MBF in the affected to the fellow eye in the superior area before and 1, 3, 6, and 12 months after surgery were 0.73, 0.51, 0.77, 0.88, and 1.01, respectively. The ratios of the MBF in the inferior area for the same periods were 0.70, 0.52, 0.75, 0.83, and 0.98, respectively. CONCLUSIONS: Eyes with an ERM showed abnormal hemodynamics in the macula that gradually improved after vitrectomy to a status comparable with the MBF of the normal fellow eye.

Adolescent↗
PubMed2001

Interferon-associated retinopathy in a uniform regimen of natural interferon-alpha therapy for chronic hepatitis C.

BACKGROUND/AIMS: The development of retinal lesions induced by a uniform regimen of interferon-alpha therapy for chronic hepatitis C was prospectively investigated. METHODS: Eighty-one patients received 6 mega units of natural interferon-alpha intramuscularly daily for 2 weeks and then 3 times a week for 22 weeks. The total dose of interferon-alpha administered was uniformly 478 mega units per patient. Two expert ophthalmologists prospectively examined the patients for retinal lesions before, during and after the therapy. RESULTS: Retinopathy was not found in comparison groups or any of the patients before treatment. In total 34.6% (28/81) of the patients showed cotton-wool spots or minor retinal hemorrhage, or both lesions, during therapy, but these lesions were reversed during or after interferon therapy. The occurrence rates of cotton-wool spots alone, retinal hemorrhage alone and both lesions were 13.6% (11/81), 6.2% (5/81), and 14.8% (12/81), respectively. The appearance of retinopathy did not correlate with patients' background including viral loads and response to the therapy, but was more frequently found in older patients and patients with hypertension and/or diabetes mellitus; disappearance of retinopathy was more prolonged than in patients without these complications. Almost all the lesions appeared 2-4 months after the start of the therapy, and the severity of the lesions did not differ between patients with and without hypertension and/or diabetes mellitus. CONCLUSION: Although it is not clear if interferon-associated retinopathy occurs in a dose-dependent manner, the present study shows a standard pattern of the occurrence of retinopathy in patients with chronic hepatitis C receiving a uniform dosage of natural interferon-alpha.

Age Distribution↗
PubMed2001

Characterization of vitamin B12 compounds from edible shellfish, clam, oyster, and mussel.

Vitamin B12 content of various edible shellfish was determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor-chemiluminescence methods. The values determined by the microbiological method were 1.2-19.8 (M/C ratio) fold greater in the shellfish than the values determined by the chemiluminescence method. Vitamin B12 compounds were purified from most eaten shellfish, oyster (M/C, 1.5), mussel (M/C, 1.2), and short-necked clam (M/C, 2.7), and partially characterized. TLC and HPLC patterns of each red-colored vitamin B12 compound (M/C, 1.0-1.2) purified from these shellfish were identical to those of authentic vitamin B12. Although the higher values in the determination of vitamin B12 by the microbiological method may be due to the occurrence of vitamin B12-substitutive compounds, the edible shellfish would be excellent vitamin B12 sources judging from the values (> or = 6 micrograms/100 g) determined by the chemiluminescence method.

Animals↗
PubMed2001

In vitro antimicrobial activities of bakuchiol against oral microorganisms.

Bakuchiol was isolated from the seeds of Psoralea corylifolia, a tree native to China with various uses in traditional medicine, followed by extraction with ether and column chromatography combined with silica gel and octyldecyl silane. In this study, the antimicrobial activities of bakuchiol against some oral microorganisms were evaluated in vitro. The cell growth of Streptococcus mutans was inhibited in a bakuchiol concentration-dependent manner, and growth of S. mutans was completely prevented by 20 microg of bakuchiol per ml. The bactericidal effect of bakuchiol on S. mutans was dependent on temperature and stable under the following conditions: sucrose, 0 to 10% (wt/vol); pH, 3.0 to 7.0; organic acids (3% [wt/vol] citric and malic acids). Bakuchiol showed bactericidal effects against all bacteria tested, including S. mutans, Streptococcus sanguis, Streptococcus salivarius, Streptococcus sobrinus, Enterococcus faecalis, Enterococcus faecium, Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus plantarum, Actinomyces viscosus, and Porphyromonas gingivalis, with MICs ranging from 1 to 4 microg/ml and the sterilizing concentration for 15 min ranging from 5 to 20 microg/ml. Furthermore, bakuchiol was also effective against adherent cells of S. mutans in water-insoluble glucan in the presence of sucrose and inhibited the reduction of pH in the broth. Thus, bakuchiol would be a useful compound for development of antibacterial agents against oral pathogens and has great potential for use in food additives and mouthwash for preventing and treating dental caries.

Anti-Bacterial Agents↗
PubMed2001

[Two elderly patients with sarcoidosis and Sjögren's syndrome].

Two elderly patients with sarcoidosis complicated with Sjögren's syndrome are described. Case 1: A 70-year-old woman was admitted due to dry eyes. Histological examination of a minor salivary gland specimen revealed lymphocytic infiltration, which was compatible with Sjögren's syndrome. Because uveitis was demonstrated, transbronchial lung biopsy (TBLB) was performed, to confirm a diagnosis of lung sarcoidosis. Histological examination of TBLB showed non-caseating granulomas compatible with sarcoidosis. Case 2: A 70-year-old woman was admitted due to dyspnea on exercise and blurred vision. Two years previously, Sjögren's syndrome was diagnosed because of a positive Shirmer test and positive SS-A antibody. Result of ophthalmic examination were compatible with uveitis. Histological examination of TBLB showed non-caseating granulomas compatible with sarcoidosis. Certain similarities between sarcoidosis and Sjögren's syndrome in terms of immunological aspects have attracted attention. In the present manuscript, a possible relationship between the two diseases as well as the characteristics of elderly sarcoidosis are discussed.

Aged↗
PubMed2001

Factors determining outcome in elderly patients with severe COPD on long-term domiciliary oxygen therapy.

The objective of the present study was to identify factors that determine outcome in elderly patients receiving long term domiciliary oxygen therapy (LTOT) for chronic obstructive pulmonary disease (COPD). One hundred fifty-seven COPD patients (121 male, 36 female) receiving LTOT were followed-up from 1983 to 1994. Univariate and multivariate analysis by Cox's proportional hazards ratio model and Kaplan-Meier survival estimates were used to quantify the relationship among a total of 34 baseline variables and overall mortality. By December 31, 1995, 96 patients (61.2%) had died and 13 (8.3%) were unavailable for follow up. Mean age of the patients was 79.2 yrs and mean duration of LTOT was 2.81 yrs. The mean FEV1 was 0.80 L and mean FEV1/FVC was 48%. The overall survival was poor and 5-yr survival was 21.6% (median survival: 3.01 yrs). Among the variables tested by univariate analysis, factors associated with poor outcome were as follows: %IBW < or = 85 (HR = 2.15, p < 0.001), serum albumin (g/dl) < or = 3.5 (1.81, p < 0.01), hemoglobin (g/dl) < or = 11.0 (1.86, p < 0.01), FEV1/FVC > 50% (0.63, p < 0.05), and high dyspnea ranking (grade 4 or 5) (1.74, p < 0.05). The coexistence of bronchiectasis (3.96, p < 0.01) and malignancy (1.85, p < 0.01) also contributed to poor outcome. Multivariate analysis showed that independent prognostic factors influencing outcome included: nutritional status (%IBW) (HR = 2.08, p < 0.01), dyspnea ranking (2.04, p < 0.01), coexistence of malignancy (2.02, p < 0.01), and FEV1/FVC (0.52, p < 0.01). We conclude that the outcome in elderly COPD patients receiving LTOT is poor, and that outcome is independently influenced by four major factors: malnutrition, severity of dyspnea, coexistence of malignancy, and airflow obstruction.

Aged↗
PubMed2001

[Cavernostomy and simultaneous removal of fungus ball of pulmonary aspergilloma].

Between 1991 and 2000, 21 patients (16 male and 5 female) underwent 28 cavernostomies for the treatment of pulmonary aspergilloma. The median age was 59.4 years (range 37-85 years). The mean %VC was 59.6 (range 30.4-91.2), and the mean FEV 1.0 was 1.51 ml (range 0.64-2.67 ml). The mean body mass index was 17.6 (range 12.7-23.2). The most common complaint was hemoptysis. The underlying lung disease was tuberculosis in 17 cases, atypical mycobacteriosis in 2, and unclassified in 2. All cases had been diagnosed as complex aspergilloma. The mean surgical duration was 136 minutes (range 85-203 min.) and the mean blood loss during surgery was 242 ml(range 5-810 ml). No death or major complications occurred in the postoperative course. During follow-up, 4 patients died of massive hemoptysis, cancer, respiratory failure or an unknown cause. Relapses of aspergilloma occurred in 9 patients (42.9%). Recavernostomy was performed safely on 5 patients. In conclusion, although the relapse rate of aspergilloma was high after cavernostomy, safe reoperations were performed. Cavernostomy is thus an effective treatment in high-risk patients.

Adult↗
PubMed2000

A new method for quantification of metamorphopsia in patients with epiretinal membrane

Purpose: We have developed a new method for quantification of metamorphopsia and applied it to study distorted vision resulting from epiretinal membrane (ERM).Patients and Methods: We prepared a modified Amsler chart, which was a square grid formed by black lines on a white background with 12 cm on a side and divided into 2-cm quadrants. The patients were asked to trace any straight lines on the chart which appeared irregular or curved. The length of all lines traced by the patients was measured except for the outer frame. The total length of the chart itself was 1.200 mm, but it would appear longer in patients with metamorphopsia. In addition, the severity of metamorphopsia was scored subjectively as follows: 1, absent; 2, slight; 3, mild; 4, moderate; and 5, severe. The relationship of the length to the score and to the visual acuity were analysed. Sixty-three patients with unilateral ERM were examined.Results: The length of the line ranged from 1,200 to 1,259 mm (mean 1,223.3 mm) and was correlated significantly to the score. Conclusions: This method might be applied usefully in evaluating the severity of metamorphopsia and the surgical outcome of eyes with ERM.

Journal Article↗
PubMed2000

Characterization of a vitamin B12 compound in the edible purple laver, Porphyra yezoensis.

The edible purple laver, Porphyra yezoensis, contained 51.49+/-1.51 microg of vitamin B12 compounds per 100 g dry weight of the laver (mean +/- SEM, n = 4). A vitamin B12 compound was purified from the lyophilized purple laver and partially characterized. The silica gel 60 TLC and reversed-phase HPLC patterns of the purified pink-colored compound were identical to those of authentic vitamin B12, but not to those of vitamin B12 analogues inactive for humans.

Biological Availability↗
PubMed2000

Swelling/deswelling mechanism of calcium alginate gel in aqueous solutions.

To elucidate the mechanism of dimensional changes in alginate impression in solutions, the relationship between the ion concentrations in three types of solutions (nonelectrolyte and monovalent and divalent metallic salts) and change in gel volume was examined. The gel in the monovalent metallic salt solution expanded and a decrease in monovalent cation and an increase in Ca2+ were observed. This suggests that the crosslinking density of the gel reduced due to dissociation of Ca2+ from the calcium alginate gel. In divalent metallic salt solutions, the shrinkage occurred according to crosslinking of unreacted residue. In the nonelectrolytic solution, gel, neither ethylene glycol nor acetonitrile showed any volume changes, while that in glutaraldehyde contracted. It is speculated that the former two solutions were affected by the fact that the gel has no semipermeability, and that the latter result was due to chemical interaction between the gel and solution.

Alginates↗
PubMed2000

[Effects of inhaled corticosteroid in elderly patients with chronic obstructive pulmonary disease].

We examined the efficacy of inhaled corticosteroid (beclomethazone dipropionate: BDP) in elderly patients with chronic obstructive pulmonary disease (COPD). Eighty-six patients with COPD were divided into 3 groups: COPD treated without BDP (group 1, n = 26), COPD treated with BDP (group 2, n = 25), and BDP-treated COPD with asthmatic symptoms (group 3, n = 35). Pulmonary function test findings, symptoms, and prognosis for the 3 groups were retrospectively compared. No significant differences in yearly decline of FEV1.0 were observed. Of the patients treated with inhaled corticosteroid (groups 2 and 3), 30% exhibited improved FEV1.0. Of these patients, monthly decline of FEV1.0 correlated negatively with bronchial reversibility in FEV1.0 before and after inhalation of salbutamol (delta FEV1.0) (r = -0.28, p = 0.03). Cough and sputum scores were significantly improved in groups 2 and 3 (p < 0.01). Fewer admissions and episodes of acute exacerbation were noted in groups 2 and 3 than in group 1. From these results, we concluded that inhaled corticosteroid was effective in elderly COPD patients with bronchial reversibility and airway symptoms.

Administration, Inhalation↗
PubMed1999

Disordered expression of the sucrase-isomaltase complex in the small intestine in Otsuka Long-Evans tokushima fatty rats, a model of non-insulin-dependent diabetes mellitus with insulin resistance.

To clarify the relationship between diabetes mellitus and carbohydrate digestion, the activities of sucrase and isomaltase, which form a complex enzyme (SI complex) on the brush border membranes, were compared in the progression of diabetes mellitus in Otsuka Long-Evans Tokushima fatty (OLETF) rats, a model of human non-insulin-dependent diabetes mellitus with insulin resistance, and Long-Evans Tokushima Otsuka (LETO) rats as non-diabetic controls. Until 40 weeks of age, OLETF rats were obese and had a high plasma glucose level, compared to age-matched LETO rats, but the sucrase and isomaltase activities showed no significant differences between the two strains. Oral glucose tolerance test revealed that during 40-48 weeks of age, NIDDM became very severe with advancing insulin resistance in OLETF rats. In OLETF rats, in contrast to LETO rats, at 48 weeks of age, abnormal increases in the sucrase and isomaltase activities occurred, along with a remarkable decrease in body weight and a further great increase in the plasma glucose level in the non-fasting state. Hyperinsulinemia occurred in 20-week-old OLETF rats; however, at 40 and 48 weeks of age, the plasma insulin level in the non-fasting state in OLETF rats was not significantly different from that in LETO rats. The level of mRNA encoding the SI complex increased abnormally in 48-week-old OLETF rats. These results suggest that the advance of insulin resistance leads to an increase in the expression of the SI complex on the transcriptional level.

Age Factors↗
PubMed1999

Mechanical properties of several nickel-titanium alloy wires in three-point bending tests.

The purpose of this study was to clarify the mechanical properties of 42 brands of nickel-titanium alloy orthodontic wires from 9 manufacturers by conducting three-point bending tests under uniform testing conditions. Manufacturers included A-Company, Hoya Medical, Lancer, Ormco, Rocky Mountain, Sankin, Tomy (GAC), TP, and 3M/Unitek. Cobalt-chrome, and titanium-molybdenum alloy wires were also tested as a reference for comparison of force levels. All reported data were recorded during the unloading process to simulate the force that a wire exerts on a tooth as it is moved into the dental arch from a position of malocclusion. The following results were obtained for the nickel-titanium wires tested. (1) Among the 0.016 inch round wires tested under a maximum deflection of 1.5 mm, the difference between the smallest (Copper nickel-titanium 35) and the largest (Aline) load values was 136 g. For the 0.016 x 0.022 inch rectangular wires tested, the difference between the smallest (Copper nickel-titanium 40) and the largest (Aline) load values was 337 g. (2) The change in load between 1.5 and 0.5 mm of deflection was examined to clarify the superelastic properties of the wires tested. For the 0.016 inch wires, 17 wire brands produced a load difference of less than 100 g, and two brands produced a difference of at least 100 g (Aline and Titanal = 100 g). For the 0.016 x 0.022 inch wires, 15 brands produced a load difference of less than 100 g, and eight brands produced a difference of over 100 g. The smallest and largest load differences were 3 g (Copper nickel-titanium 35) and 200 g (Aline). (3) The majority of the samples with a smaller load difference between deflections of 1.5 mm and 0.5 mm in the unloading process were found among super-elastic wires, while samples with a larger load difference were predominantly found among work-hardened wires. Compared with cobalt-chrome and TMA wires, nickel-titanium alloy wires exert significantly less force. However, the amount of force varies greatly from brand to brand. Consequently, when using nickel-titanium alloy wires, brands must be selected carefully by taking into consideration the severity of the malocclusion and the stage of orthodontic treatment in each case. It is the intent of this study to offer clinicians an unbiased guide for the selection of appropriate nickel-titanium alloy wires.

Dental Alloys↗
PubMed1999

Dried green and purple lavers (Nori) contain substantial amounts of biologically active vitamin B(12) but less of dietary iodine relative to other edible seaweeds.

Vitamin B(12) concentrations of dried green (Enteromorpha sp.) and purple (Porphyra sp.) lavers (nori) were determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor chemiluminescence methods. The values determined by using the microbiological method (63.58 +/- 2.90 and 32.26 +/- 1.61 microg/100 g of dry weight) were identical to those found by using the chemiluminescence method (69.20 +/- 2.21 and 25.07 +/- 0.54 microg/100 g of dry weight) in both dried green and purple lavers, respectively. A silica gel 60 thin-layer chromatography of both laver extracts shows that non-coenzyme forms (hydroxo and cyano forms) of vitamin B(12) predominate in both dried lavers. The dried lavers contained lesser amounts of dietary iodine ( approximately 4-6 mg/100 g of dry weight) relative to other seaweeds, suggesting that excessive intake of the dried lavers is unlikely to result in harmful intake of dietary iodine. These results indicate that the dried lavers (nori) are the most excellent source of vitamin B(12) among edible seaweeds, especially for strict vegetarians.

Iodine↗
PubMed1999

Pseudovitamin B(12) is the predominant cobamide of an algal health food, spirulina tablets.

The vitamin B(12) concentration of an algal health food, spirulina (Spirulina sp.) tablets, was determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor chemiluminescence methods. The values determined with the microbiological method were approximately 6-9-fold greater in the spirulina tablets than the values determined with the chemiluminescence method. Although most of the vitamin B(12) determined with the microbiological method was derived from various vitamin B(12) substitutive compounds and/or inactive vitamin B(12) analogues, the spirulina contained a small amount of vitamin B(12) active in the binding of the intrinsic factor. Two intrinsic factor active vitamin B(12) analogues (major and minor) were purified from the spirulina tablets and partially characterized. The major (83%) and minor (17%) analogues were identified as pseudovitamin B(12) and vitamin B(12), respectively, as judged from data of TLC, reversed-phase HPLC, (1)H NMR spectroscopy, ultraviolet-visible spectroscopy, and biological activity using L. leichmannii as a test organism and the binding of vitamin B(12) to the intrinsic factor.

Bacterial Proteins↗