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Biomedical subjects

S Yoshida

Publications and source records attributed to S Yoshida.

At least 343 records · Page 19Linked to original sources
PubMed2000

Impairment of osteocalcin production in senescent periodontal ligament fibroblasts.

Osteocalcin production of senescent periodontal ligament fibroblasts (PDLF) with the expression of senescence-associated beta-galactosidase (SA-beta-Gal) was investigated on clones from 50-80 years old donors (n=20) with teeth extracted due to periodontitis and dental caries, and from 15-19 year old donors (n=20) with normal teeth extracted for orthodontic reasons. Immunohistochemically, the nonsenescent PDLF in all cultures in passage 2 showed strong reactivity with anti-osteocalcin. The reactive intensity of PDLF (passage 2, PD 3.0) was significantly stronger in 50-80 year old donor group than in 15-19 year old donor group, suggesting that osteocalcin production of PDLF cultured in early passage is larger in cells from adult population than in cells from adolescent population. In PDLF cultures in passage 2 from 50-80 year old donor, two types of senescent cells were found: one with strong reactivity to anti-osteocalcin and the other with little detectable reactivity. The culture consisted of senescent PDLF (passage 8, PD 14.8) did not include cells which have a detectable reactivity with anti-osteocalcin immunohistochemically and the reactive intensity was significantly weaker in the senescent culture than in the culture in passage 2 by ELISA. This suggests that the production potential of osteocalcin is impaired in PDLF with aging in culture. Further, the reactive intensity with anti-osteocalcin of PDLF in passage 2 deprived of serum for 48 h was 6% of that of cells cultured with serum and the reaction increased after serum stimulation, suggesting that the osteocalcin production in PDLF in early passage is implicated in mitogenic stimulation.

Adolescent↗
PubMed2000

Double expressions of connexin 43 and 32 in human periodontal ligament fibroblasts.

The expressions of connexin 43 and 32 in cultured and intact human periodontal ligament fibroblasts (PDLFs) were examined using immunohistochemical methods, and western blot analysis was conducted with anti-connexin 43 and 32 in cultured PDLFs. The PDLFs both in cultured cells and tissue sections reacted with anti-connexin 43 and 32, and western blot analysis showed bands of approximately 43 kD and 27 kD reacted with anti-connexin 43 and 32 respectively, suggesting the existence of gap junctions in human PDLFs. In cultured PDLFs there were no reaction products of connexin 43 when the cells were not in contact with adjacent cells, but reaction products were increasingly observed with increases in cell-cell contacts. Different from connexin 43, the reaction products of connexin 32 were found in the cytoplasm, regardless of whether the cells were or were not in contact with adjacent cells. Further, the reaction activity of connexin 32 varied among PDLFs; some were strong, some moderate, and some weak. The expressions of connexin 43 and 32 in human PDLFs are suggested to be related to the regulation of two different functions of the PDLFs.

Adolescent↗
PubMed2000

Recurrence after endoscopic mucosal resection for superficial esophageal cancer.

BACKGROUND AND STUDY AIMS: We present the results of endoscopic mucosal resection (EMR) for superficial esophageal cancer in patients treated at the National Cancer Center Hospital East since March 1993, and discuss the factors involved in local recurrence. PATIENTS AND METHODS: The study consisted of 51 patients with a total of 57 superficial esophageal cancers which were treated by EMR at the National Cancer Center Hospital East between March 1993 and March 1998. EMR was performed with a two-channel fiberscope or with the assistance of the endoscopic esophageal mucosal resection tube. Follow-up examinations by means of endoscopy with iodine staining and biopsy were repeated every 3-6 months. RESULTS: A total of 19 patients had double cancers; 12 had head and neck cancers (HNC), six had stomach cancers, and one had lung cancer. The patients with HNC tended to have multiple iodine-unstained areas, and multiple cancers in the esophagus. Local recurrence was detected in two out of five patients (40%) with multiple esophageal cancers, and in two out of 46 patients (4%) with solitary cancer (P=0.0433). There was no difference in the rate of local recurrence between patients with HNC and those without HNC. Three out of four patients with recurrent cancers were given additional treatment, EMR for two and radiotherapy alone for one; no further recurrence occurred except in the patient who underwent radiotherapy alone. CONCLUSIONS: Multiplicity of cancer is a risk factor for local recurrence. Appropriate additional treatment should be indicated for recurrent lesions.

Aged↗
PubMed2000

Relationship of nasal carriage of Staphylococcus aureus to pathogenesis of perennial allergic rhinitis.

BACKGROUND: Several studies have previously shown some factors that modify the pathogenesis of perennial allergic rhinitis (PAR). However, the association between bacterial colonization and PAR has not been well understood. OBJECTIVE: We sought to study the association between superantigen-producing Staphylococcus aureus and PAR. METHODS: S aureus colonization in the nasal cavity and its superantigen production were studied in 65 patients with PAR and 45 nonallergic control subjects. The nasal symptom scores of the patients were evaluated. Furthermore, we examined the response to staphylococcal enterotoxin B or toxic shock syndrome toxin 1 of peripheral blood lymphocytes from both patients and control subjects by measuring proliferative responses and production of cytokines (IFN-gamma, IL-4, and IL-5). RESULTS: The rate of nasal carriage of S aureus in the patients (44%) was significantly higher than that of the control subjects (20%, P <.01). Moreover, the rate of nasal carriage of superantigen-producing S aureus in the patients (22%) was significantly higher than that of the control subjects (6.7%, P <.05). The nasal symptom scores of the S aureus -positive patients were significantly higher than those of the S aureus -negative patients (P <.05), although there was no significant association between symptom scores and superantigen production. Peripheral blood lymphocytes from the patients showed significantly higher proliferative responses and were more likely to produce T(H2 )type cytokines in response to superantigens (P <.01), but the responses were not different among the patients with S aureus carriage and superantigen production. CONCLUSION: This study suggests that PAR leads to a higher carriage rate of S aureus, and nasal carriage of S aureus may aggravate PAR.

Adolescent↗
PubMed2000

5' flanking region polymorphism of the gene encoding leukotriene C4 synthase does not correlate with the aspirin-intolerant asthma phenotype in the United States.

BACKGROUND: Approximately 10% of patients with asthma have a distinct clinical entity in which their symptoms are exacerbated by aspirin and most other nonsteroidal anti-inflammatory agents. These individuals typically have significant basal overproduction of cysteinyl leukotrienes, and within their biosynthetic pathway, the terminal enzyme, leukotriene C(4) synthase (LTC(4)S), is significantly overexpressed. A single nucleotide polymorphism consisting of an adenine (A) to cytosine (C) transversion -444 nucleotides upstream of the ATG translation start site in the LTC(4)S gene has been associated with a relative risk of 3.89 for the aspirin-intolerant phenotype in Polish patients. OBJECTIVE: These studies were undertaken to further investigate the functional effect of this allele in LTC(4)S gene expression and subsequently to determine whether an association between the presence of this polymorphism and aspirin-intolerant asthma existed within patients of the United States. METHODS: Functionality of the C-444 allele was assessed by using promoter-reporter constructs and transient transfection assays in the THP-1 monocytic cell line. Genotyping was performed on 137 unaffected control subjects, 33 patients with aspirin-tolerant asthma, and 61 patients with aspirin-intolerant asthma from the United States. RESULTS: Promoter-reporter constructs containing the C-444 allele revealed no significant upregulatory or downregulatory effects in the transcription of the LTC(4)S gene. The LTC(4)S genotype distribution was consistent with the Hardy-Weinberg equilibrium in patients with aspirin-tolerant asthma and unaffected control subjects but not in patients with aspirin-intolerant asthma; however, the distributions were not significantly different among the phenotype groups. CONCLUSIONS: Our data demonstrate that the C-444 allele in the LTC4S gene is not statistically different among patients with the aspirin-intolerant asthmatic phenotype, patients with the aspirin-tolerant asthmatic phenotype, and unaffected control subjects in the United States. This finding, along with the lack of functionality of this polymorphism, suggest that it is not related to a specific asthma phenotype and may represent a population-stratified polymorphism within patients of eastern European descent.

Alleles↗
PubMed2000

Keratinocyte growth factor in the promotion of human chorionic gonadotropin production in human choriocarcinoma cells.

OBJECTIVE: Several growth factors and cytokines appear to participate in the proliferation or differentiation of trophoblast cells. The purpose of this study was to investigate the extent to which keratinocyte growth factor participates in the development of human embryonic and trophoblast cells at the maternal-fetal interface. STUDY DESIGN: The reverse transcriptase-polymerase chain reaction method was used to determine the gene expression of keratinocyte growth factor and keratinocyte growth factor receptor in human choriocarcinoma cells (BeWo), human teratocarcinoma cells (PA-1), and human endometrial stromal cells. We also examined the effects of keratinocyte growth factor on cell proliferation and production of human chorionic gonadotropin in BeWo and PA-1 cells. RESULTS: Keratinocyte growth factor gene was expressed in all cell types. The expression was pronounced in stromal cells of the endometrium collected during the secretory phase and early pregnancy. The keratinocyte growth factor expression was also enhanced in the differentiated BeWo cells. The expression of keratinocyte growth factor receptor gene was observed only in the BeWo cells. The addition of keratinocyte growth factor to the medium did not affect cell proliferation of the BeWo and PA-1 cells. On the other hand, keratinocyte growth factor (100 ng/mL) significantly enhanced human chorionic gonadotropin production in the BeWo cells. Stimulatory action of keratinocyte growth factor on human chorionic gonadotropin production in the BeWo cells was markedly enhanced after forskolin-induced differentiation. CONCLUSIONS: We conclude that keratinocyte growth factor may play an important role in promotion of human chorionic gonadotropin production in the trophoblast cells.

Cell Division↗
PubMed2000

Visual dominance in amending the directional parameter of feedforward control.

The authors examined visual dominance between trials in which the movement program was amended (i.e., off-line processing). Weighting between visual and proprioceptive feedback was examined in a trial-by-trial analysis of the directional parameter of feedforward control. Eight participants moved a cursor to a target displayed on a computer screen by manipulating a hand-held stylus on a digitizing tablet. In the first 30 trials, the cursor followed the stylus movement (practice condition). In the next 30 trials, the directional error of the stylus movement was presented in the opposite direction (reversal condition). Subjects knew the presence and the nature of the reversal. In the last 10 trials, the reversal was withdrawn (transfer condition). Directional error of feedforward control was relatively small in the practice condition, and it increased gradually in 1 of 2 directions as trials proceeded in the reversal condition. Positive aftereffect was observed in the transfer condition. A constant increment of the directional error indicated that both visual and proprioceptive feedback are registered, with higher weight on vision, and that weighting between those inputs is determined automatically or is fixed without any strategic control.

Adult↗
PubMed2000

Evaluation of pulmonary gas exchange after lobectomy and simple thoracotomy.

Postoperative influence of simple thoracotomy and lobectomy on pulmonary gas exchange was investigated in 10 patients undergoing thoracotomy and lobectomy (L group) and 10 patients with simple thoracotomy (ST group). Gas exchange was assessed with hot-wire mass spectrometry and blood gas analyses preoperatively and postoperatively at 1, 3, 6, 12, 24 and 48 h and on days 4, 6 and 13. The preoperative values of alveolar-arterial oxygen tension gradient (AaDO2), ventilation-perfusion mismatch (V(A)/Q) and circulatory shunt (Qs/Qt) were maintained in the ST group. In the L group, however, AaDO2 and Qs/Qt showed good maintenance of gas exchange for only 6-12h after lobectomy and then deteriorated because of peripheral atelectasis, resulting in poorer values than those in the ST group on days 4 and 13. Careful postoperative management, including pulmonary toilet, is essential for maintenance of gas exchange and prevention of pulmonary complications.

Adult↗
PubMed2000

Neuropsychological EEG activation in patients with epilepsy.

To examine the effects of higher mental activity on the EEG, 480 Japanese patients with different types of epilepsy were subjected to potentially provocative cognitive tasking, termed 'neuropsychological EEG activation' (NPA), during standard EEG recordings. NPA tasks consisted of reading, speaking, writing, written arithmetic calculation, mental arithmetic calculation and spatial construction. The NPA tasks provoked epileptic discharges in 38 patients (7.9%) and were accompanied by myoclonic seizures in 15 patients, absence seizures in eight and simple partial seizures in one. Among the cognitive tasks, mental activities mainly associated with use of the hands, i.e. writing (68.4%), written calculation (55. 3%) and spatial conction (63.2%), provoked the most discharges, followed by mental calculation (7.9%) and reading (5.3%). Detailed examination of the precipitating events revealed action-programming type activities to be the most crucial in 32 out of the 38 patients (84.2%), followed by thinking type activities in four patients (10. 5%). Regarding the classification of epilepsies proposed by the International League Against Epilepsy, seizure-precipitating mental activities in our series were almost exclusively (in 36 out of the 38 patients) related to idiopathic generalized epilepsies (IGEs) including juvenile myoclonic epilepsy, juvenile absence epilepsy, grand mal epilepsy on awakening and childhood absence epilepsy, and were rarely (in only two out of the 38 patients) related to temporal lobe epilepsy. In our IGE patients, the provocative effects of NPA were related to myoclonic seizures rather than absence or generalized tonic-clonic seizures. These results suggest that NPA is a useful tool for examining the relationship between cognitive function and epileptic seizures, and that the IGE patients with myoclonic seizures are vulnerable to higher mental activities requiring action-programming or thinking.

Adolescent↗
PubMed2000

A case of inoperable esophageal carcinoma with hepatic and nodal metastases which showed a long-term survival after chemoradiotherapy including nedaplatin.

We report a case of metastatic esophageal carcinoma successfully treated with chemoradiotherapy. A 61-year-old man, diagnosed as suffering from advanced esophageal carcinoma with liver and lymph node metastases, was treated with a combination of nedaplatin (90 mg/m2/day, 1 h drip infusion, day 1), 5-fluorouracil (800 mg/m2/day, continuous infusion, days 1-5), and radiotherapy (2 Gy/day, days 1-5, 8-12 and 15-19). The cycle was repeated twice every 5 weeks from July 2, 1997. He achieved a complete response 1 month after finishing two courses of chemoradiotherapy followed by an additional three courses of chemotherapy without radiation. Seven months after the completion of radiotherapy, pericardial effusion with negative cytology was recognized. The effusion was treated by pericardiocentesis and drainage for several days. After drainage, the effusion could be easily managed with diuretics. This patient is still alive with no evidence of disease more than 2.5 years after the initiation of the treatment.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2000

Stress-induced factor involved in flower formation of Lemna is an alpha-ketol derivative of linolenic acid.

A stress-induced substance(s) (factor C) incubated with norepinephrine (NE) has strong flower-inducing activity in Lemna paucicostata. We isolated an essential component (FIF) of factor C, and clarified its chemical structure as 9-hydroxy-10-oxo-12(Z),15(Z)-octadecadienoic acid, an alpha-ketol derivative of linolenic acid, which is formed via 9-hydroperoxy linolenic acid. Synthesized FIF showed flower-inducing activity after incubation with NE (factor C activity) equivalent to that formed in the stressed Lemna. Jasmonic acid and 13-hydroxy-12-oxo-9(Z),15(Z)-octadecadienoic acid (12,13-alpha-ketol linolenic acid), both of which are formed via 13-hydroperoxide of linolenic acid and all other derivatives of FIF synthesized by chemical and enzymatic processes failed to show the factor C activity. These results suggest that the molecular structure of FIF is very specific for the factor C activity.

Fatty Acids, Unsaturated↗
PubMed2000

Purification from conditioned medium and chemical identification of a factor that inhibits somatic embryogenesis in carrot.

Somatic embryogenesis is strongly inhibited in cultures of carrot (Daucus carota L.) cells when the cell density is high. The inhibition is caused by factors that are released by cells into the medium of such cultures. In this study, we purified and identified one of the inhibitory factors found in the medium of high-cell-density cultures of carrot cells. The inhibitory factor with the strongest apparent activity was purified by fractionation with ethylacetate, chromatography on an octadecylsilyl (ODS) silica gel-column and HPLC. The inhibitory factor had a single peak of absorbance at 280 nm and was identified as 4-hydroxybenzyl alcohol by mass spectrometry and 1H- and 13C-NMR spectroscopy. Authentic 4-hydroxybenzyl alcohol strongly inhibited the formation of somatic embryos at a concentration equal to that in high-cell-density cultures. These results suggest that 4-hydroxybenzyl alcohol is a major factor that accumulates in high-cell-density cultures of carrot cells and inhibits somatic embryogenesis.

Benzyl Alcohols↗
PubMed2000

Purification and properties of protoporphyrinogen oxidase from spinach chloroplasts.

Protoporphyrinogen oxidase (Protox), an enzyme that catalyzes the common step of chlorophyll and heme biosynthetic pathways, was purified from spinach chloroplasts. The molecular weight of purified protein was estimated to be approximately 60,000 by SDS-PAGE. Protox activity was stimulated by addition of FAD, suggesting that chloroplast Protox requires FAD as a cofactor. Furthermore, the Protox-inhibiting herbicide, S23142, specifically inhibited the purified Protox activity at an IC50 value of 1 nM.

Chromatography, Gel↗
PubMed2000

Resistance induction in barley coleoptile cells by intracellular pH decline.

Cytoplasmic acidification in suspension-cultured plant cells has been characterized as a common intracellular response of some kinds of plant cells to elicitors. Expression of various defense genes in these cells has been increased by the cytoplasmic acidification itself without treatment by elicitors. It is not evident, however, whether or not cells with acidified cytoplasm actually exhibit resistance to the pathogen because of the lack of an adequate infection system between cultured plant cells and some pathogens. Using barley coleoptiles rather than suspension-cultured cells, we demonstrated both detection of cellular pH decline and increased resistance to Blumeria graminis. The cytoplasmic pH of barley coleoptile cells floated on 1 mM citrate buffer (CB), pH 4.0, became 0.5 unit lower than that of cells floated on 1 mM CB, pH 8.0, within 30 min after treatment. The penetration efficiency of B. graminis into the coleoptile was decreased in a pH-dependent manner; that is, when the coleoptiles were floated on 1 mM CB, pH 8.0, the penetration efficiency of the fungi was about 80%. In contrast, when the coleoptiles were floated on acidic buffers, the penetration efficiency decreased in parallel the decline of pH and the penetration efficiency reached 0% when coleoptiles were floated on 1 mM CB, pH 4.0. Morphogenesis of appressoria on the coleoptiles floating on CB was not influenced. The lowered penetration efficiency at lower pH was partially cancelled when the barley coleoptiles were irradiated with UV for 5 min prior to B. graminis inoculation. These findings suggest that the decline in cytoplasmic pH in barley coleoptile cells increases resistance to the pathogenic fungus B. graminis.

Cytoplasm↗
PubMed2000

Delayed paraplegia caused by the gradual collapse of an infected vertebra.

A case of delayed paraplegia caused by a gradual and progressive collapse of a vertebra after healing of pyogenic spondylitis is reported. A 73-year-old man was treated for a hematogenously seeded pyogenic spondylitis of the first lumbar vertebra. Magnetic resonance imaging showed a high signal intensity of the involved vertebra and adjacent discs and a paravertebral abscess without disc space narrowing. Eight months after healing of the infection, the patient had muscle weakness and paresthesia of the lower extremities, which gradually increased. The plane radiographs revealed a kyphotic deformity of 36 degrees with a collapse of the first lumbar vertebra.

Abscess↗
PubMed2000

Macular buckling for retinal detachment due to macular hole in highly myopic eyes with posterior staphyloma.

PURPOSE: To evaluate the efficacy of macular buckling surgery using a special exoplant. METHODS: The authors reviewed 33 cases of patients with retinal detachment due to macular hole with posterior staphyloma who underwent a macular bucking procedure and 11 cases of patients with the same condition due to macular hole without posterior staphyloma or due to a hole along the edge of the posterior staphyloma who underwent gas injection or vitrectomy. The reattachment rate, visual acuity (VA), and area size (V-4, I-4 isopter) by Goldmann perimetry were calculated. RESULTS: Reattachment rate for the macular buckling procedure was 94% (initial) and 100% (final), and that for the gas injection or vitrectomy was 100% (both initial and final). Twenty of the 33 eyes (60.6%) had VA of 20/400 or better, and none of these 33 eyes had a VA at the level of finger counting or poorer following macular buckling. Nine of the 11 eyes (81.8%) had VA of 20/400 or better, and none of these 11 eyes had a VA at the level of finger counting or poorer following the gas injection or vitrectomy. The area size of V-4 isopter in the macular buckling group was significantly larger than that in the gas injection or vitrectomy group (P = 0.017). CONCLUSION: The macular buckling procedure is effective when considered both from an anatomic and a functional perspective for retinal detachment due to macular hole with posterior staphyloma.

Aged↗
PubMed2000

Janibacter brevis sp. nov., a new trichloroethylene-degrading bacterium isolated from polluted environments.

Two strains that were strongly able to degrade trichloroethylene were isolated from contaminated environmental samples. The isolates are non-motile, aerobic, non-spore-forming, gram-positive coccoid to short rods with cell-wall peptidoglycan containing meso-diaminopimelic acid. The major type of menaquinone is MK-8(H4). The polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol. Mycolic acids were absent. The G+C content of the DNA was 72 mol%. Furthermore, comparison of 16S rDNA sequences shows that the isolates clearly belong to the genus Janibacter. The isolates differ from Janibacter limosus at the species level, as shown by the value for DNA-DNA hybridization. It is therefore proposed that the strains be assigned to the genus Janibacter as Janibacter brevis sp. nov.

Actinomycetales↗