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Biomedical subjects

Y Katoh

Publications and source records attributed to Y Katoh.

320 records · Page 18Linked to original sources
PubMedDate not supplied

Action of phenolic antioxidants on various active oxygen species.

The action of phenolic antioxidants, such as probucol, on various active oxygen species was investigated using luminol chemiluminescence and spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO). The various active oxygen species, including hydroxyl radicals (Fenton reaction), superoxide anions, singlet oxygen and hypochlorite ions were examined with phenolic antioxidants under aqueous and nonaqueous conditions. Probucol showed a quenching effect on both superoxide anions and hypochlorite ions in nonaqueous solution. However, it had no effect on hydroxyl radicals. alpha-Tocopherol, a natural phenolic antioxidant, showed a stronger quenching effect on superoxide anions and hypochlorite ions than probucol, and quenched hydroxyl radicals in nonaqueous solution. Furthermore, Trolox showed a quenching effect on all active oxygen species in both aqueous and nonaqueous solution. The antioxidants were studied under comparable conditions in a series of test systems and the reactivity profiles depicted as 'radar charts' which are helpful for characterizing antioxidant action.

Antioxidants↗
PubMedDate not supplied

Talonavicular arthrodesis for isolated arthrosis: 9.5-year results and gait analysis.

Eleven patients who were treated for talonavicular arthrosis with a talonavicular arthrodesis between 1961 and 1979 at the Mayo Clinic have been reviewed. Follow-up from surgery ranged from 2.5 to 21 years with a mean of 9.5 years. Clinical, radiographic, and gait analyses were obtained. All patients had satisfactory pain relief, but all noted difficulty in ambulating on irregular ground. Three patients had roentgenographic evidence of arthrosis affecting other tarsal joints that had not been involved before arthrodesis. Gait analysis revealed decreased terminal stance-phase plantarflexion and pronounced reduction of subtalar motion. Talonavicular arthrodesis does give predictable union and patient satisfaction but results in limitation of subtalar motion and loss of stance-phase plantarflexion.

Adult↗
PubMedDate not supplied

Mitchell osteotomy for hallux valgus: long-term follow-up and gait analysis.

In this retrospective study of 96 Mitchell first-metatarsal osteotomies performed on 69 patients with an average follow-up of 7 years, we found that more than 86% were completely satisfied and that the procedure was equally effective in all age groups. Excessive first metatarsal shortening, dorsiflexion of the osteotomy, and failure to correct the intermetatarsal angle to 10 degrees or less correlated with poorer results. This study demonstrates a relationship between metatarsal shortening and osteotomy plantarflexion. Gait analysis demonstrated that these patients do not have normal foot mechanics postoperatively.

Adolescent↗
PubMedDate not supplied

Objective technique for evaluating painful heel syndrome and its treatment.

The biomechanical evaluation of patients with painful heels has received only limited attention although the potential morbidity and disability associated with such an ailment can be severe. An objective analysis of the patient's foot function during gait can produce useful information to assess the underlying pathology. This method can also help to evaluate the efficacy of various existing treatment protocols. The impulse distribution based on foot-floor vertical reaction force and time under the hind-, mid-, and forefoot was determined in 32 normal subjects while walking in their usual street shoes. Variations related to shoe types were noted, with high heeled shoes causing the most significant deviations from normal. The same technique was applied to 13 painful heel syndrome patients. Characteristic deviations from the normal impulse distribution were noted in these patients which provided the basis for differentiating the pathological condition between the patients with painful heel pads and those with plantar fasciitis. The effectiveness of using heel cups as a therapeutic device was also assessed. Although significant gait changes were not associated with the insertion of heel cups, they did seem to shift the foot-floor impulse forward from the heel region, which made them effective in patients afflicted with localized heel pain, but not in those with plantar fasciitis.

Adult↗
PubMedDate not supplied

A case of pulmonary adenocarcinoma with overexpression of multidrug resistance-associated protein and p53 aberration.

A 66-year-old female patient underwent left upper lobectomy and dissection of the mediastinal lymph nodes. The pathological diagnosis was well-differentiated papillary adenocarcinoma of the lung with metastasis to the mediastinal lymph nodes, p-T2N2MO, stage IIIA. After the operation, she was treated by chemotherapy including lipophilic anticancer compounds (carboplatin and VP-16). The patient unexpectedly showed long survival for 6 years and 2 months without obvious recurrence or metastasis of the cancer. The anticancer compounds were not effective on the recurrent lesions and then she died due to respiratory failure 8 months after recurrence. The autopsy revealed pleural dissemination and intrapulmonary metastasis. Immunohistochemical analysis showed increased multidrug resistance-associated protein (MRP)-positive tumor cells in the recurrent and metastatic lesions, while few MRP-positive cells were apparent in the primary lesion. The MRP-positive cells were accompanied by p53 nuclear accumulation in the carcinoma. This was a case of pulmonary adenocarcinoma with acquired multidrug resistance caused by MRP overexpression and aberrant p53 after chemotherapy.

Adenocarcinoma, Papillary↗
PubMedDate not supplied

Influence of colonization with mutans streptococci on caries risk in Japanese preschool children: 24 month survival analysis.

PURPOSE: This study evaluates how various microbial- and salivary-related risk factors influenced the hazard for caries development in preschool children. METHODS: The study population consisted of 131 subjects (age: 0.5 to 6.0 yrs). Oral examination, including two bacterial tests and buffering capacity test, was conducted at six month intervals over 24 months. A survival analysis was used to describe caries hazard over a 24-month follow-up period. A Cox proportional hazards regression analysis was performed to test the influence of salivary mutans streptococci (MS), aciduric bacteria, buffering capacity and age on caries development. RESULTS: Of the total subjects, 60 children (46%) were found to be caries-free at baseline. Caries hazard correlated significantly with salivary MS levels at baseline (relative risk, 1.7; P = 0.003), but not with aciduric bacteria and buffering capacity. This analysis showed that all of children with high colonization of MS at baseline had dental caries 15 months later. CONCLUSION: The results suggest that salivary MS level at baseline influenced caries hazard in preschool children.

Buffers↗
PubMedDate not supplied

Newly-developed diamond points for conservative operative procedures.

The rapid decrease in the size of dental restorations has increased the demand for the smallest rotary cutting instrument possible. The width of cavities prepared with two experimental diamond points and the smallest commercial diamond point were compared and significant differences found. SEM observation of the head surfaces of the three diamond points revealed that the experimental points had comparable cutting characteristics with the commercial diamond point.

Analysis of Variance↗
PubMedDate not supplied

Effect of bonding variables on the shear bond strength and interfacial morphology of a one-bottle adhesive.

This study's objectives were: 1) to determine the combination of bonding procedures (with or without acid etching, moist or dry substrate, one or two applications of primer/adhesive) that would produce the highest shear bond strength of Prime & Bond and Dyract AP and 2) to characterize the resin-dentin/enamel interface produced by these bonding procedures. Ninety-six bovine incisors were randomly assigned to eight groups for shear bond testing to enamel (n = 6) and dentin (n = 6). Prime & Bond and Dyract AP were applied and cured following manufacturers' instructions. Shear bond testing was conducted in a Universal Testing Machine. Thirty-two bovine incisors were sectioned to produce blocks with enamel and dentin, then bonded in pairs for evaluation of interfacial morphology. They were polished and argon ion-etched using a high-speed argon ion-etching machine and examined by SEM. The groups where enamel was etched, kept moist or dry and received a single application of Prime & Bond produced the highest shear bond strength. Dentin bond strengths were high in the groups where dentin was etched and kept moist. The number of Prime & Bond applications had no effect on dentin bond strength. Acid etching results in better adaptation of Prime & Bond to enamel and dentin regardless of whether moisture is present.

Acid Etching, Dental↗
PubMedDate not supplied

Biomechanical analysis of foot function during gait and clinical applications.

Temporal and distance gait factors, foot-switch contact patterns, ankle/subtalar joint motion, and center of foot pressure distribution have been used to evaluate normal and abnormal foot mechanics. A normal control group and selected patients with well defined pathologic conditions were studied to examine the effectiveness of this method. Biomechanical observations reflect the clinical pathologic condition. Abnormalities involving the forefoot, midfoot, and hindfoot are most suitable for analyzing center of foot pressure. Ankle and subtalar problems are studied by motion analysis, with the subject walking on different ground conditions.

Adult↗
PubMedDate not supplied

Gene expression of granulocyte colony stimulating factor (G-CSF) in non-small cell lung cancer.

Autonomous or continuous granulocyte colony-stimulating factor. (G-CSF)-production in malignant neoplasms is considered to induce leukocytosis without apparent infection. We examined G-CSF gene expression in human non-small cell lung cancer (NSCLC) and discussed its clinicopathological significance. Northern blot analysis revealed G-CSF gene expression in 14 of 84 surgical specimens (16.7%, 10/30 squamous cell carcinoma, 3/50 adenocarcinoma, 1/4 large cell carcinoma). Eight patients (57.1%, 8/14) with NSCLC showing G-CSF gene-expression had peripheral blood leukocytosis (> 8,000/microliter). The prognosis was significantly worse in 10 stage I or II NSCLC showing G-CSF gene expression (p < 0.01, Cox-Mantel test). These findings suggest that G-CSF gene expression is common event in the early stage of primary NSCLC, while it cannot completely explain the leukocytosis induced by lung cancer.

Adenocarcinoma↗