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Biomedical subjects

Y Yoshida

Publications and source records attributed to Y Yoshida.

At least 253 records · Page 14Linked to original sources
PubMed2000

Evidence of chemical bonding at biomaterial-hard tissue interfaces.

For many years, glass-polyalkenoate cements have been described as possessing the unique properties of self-adherence to human hard tissues, such as bones or teeth. However, direct experimental evidence to prove the existence of chemical bonding has not been advanced. X-ray Photoelectron Spectroscopy (XPS) was used to analyze the chemical interaction of a synthesized polyalkenoic acid with enamel and synthetic hydroxyapatite. For both enamel and hydroxyapatite, the peak representing the carboxyl groups of the polyalkenoic acid was detected to have significantly shifted to a lower binding energy. De-convolution of this shifted peak disclosed two components with a peak representing unreacted carboxyl groups and a peak suggesting chemical bonding to hydroxyapatite. On average, 67.5% of the carboxyl groups of the polyalkenoic acid were measured to have bonded to hydroxyapatite. XPS of hydroxyapatite also disclosed its surface to be enriched in calcium and decreased in phosphorus, indicating that phosphorus was extracted at a relatively higher rate than calcium. Analysis of these data supports the mechanism in which carboxylic groups replace phosphate ions (PO4(3-)) of the substrate and make ionic bonds with calcium ions of hydroxyapatite. It is concluded that an ultrathin layer of a polyalkenoic acid can be prepared on a hydroxyapatite-based substrate by careful removal of non-bonded molecules. With this specimen-processing method, XPS not only provided direct evidence of chemical bonding, but also enabled us to quantify the percentages of functional groups of the polyalkenoic acids that bonded to calcium of hydroxyapatite.

Binding Sites↗
PubMed2000

Structure-activity relationships of a new antifungal imidazole, AFK-108, and related compounds.

Fungicidal activity of widely used imidazole antifungal drugs in topical applications is not so strong in spite of their fungistatic activities against dermatophytes and pathogenic yeasts. In order to improve fungicidal activity of imidazole antifungal agents, a series of novel imidazole derivatives having a hydrophobic substituent derived from isoprenoid were synthesized. The efficacy of these compounds was evaluated with respect to direct cell-membrane damaging activity, ergosterol biosynthesis inhibition, minimum growth-inhibitory concentration (MIC) and therapeutic effect for experimental dermatophytosis of guinea pigs. Among the newly synthesized compounds, the geranyl derivative named AFK-108 (2a) showed the highest in vivo fungicidal activity with both cell membrane damaging activity and ergosterol biosynthesis inhibition in vitro.

Animals↗
PubMed2000

[A cross-sectional study on the relationship of plasma fibrinogen concentration and age, physical fitness, lifestyle and health examinations of healthy Japanese males].

The intention of this study was to examine the determinants of plasma fibrinogen concentrations in healthy Japanese male workers. A cross-sectional study was conducted in 1998 among 1,044 (male 975, female 69) employees aged 30-59 years in Osaka, Japan. The overall mean value of plasma fibrinogen concentration was 236.4 +/- 47.6 mg/dl. There was a dose-response relationship between cigarette smoking and plasma fibrinogen concentration. Plasma fibrinogen concentration was associated with age, body weight, body mass index, white blood cell count and CPITN score, and inversely associated with serum HDL cholesterol in male nonsmokers. Plasma fibrinogen was not related to physical exercise, alcohol consumption or dietary factors. This study confirms the relationship of known coronary risk factors to plasma fibrinogen concentration in Japanese male factory workers, and suggests that smoking and periodontal disease are related to plasma fibrinogen concentrations.

Adult↗
PubMed2000

Comparison of vectorcardiographic and 12-lead electrocardiographic detections of abnormalities in repolarization properties due to preexcitation in patients with Wolff-Parkinson-White syndrome: proposal of a novel concept of a "remodeling gradient".

Repolarization abnormalities after radiofrequency ablation in patients with manifest Wolff-Parkinson-White syndrome (WPW) have been attributed to cardiac memory of pre-existing changes in repolarization properties. We compared spatial ventricular gradient (VG) from vectorcardiograms with QRST values of 12-lead ECG in 41 patients with WPW (group A, manifest WPW due to left-sided accessory pathway (n = 20); group B, manifest WPW due to right-sided accessory pathway (n = 12); group C, concealed WPW (n = 9)) before and after ablation. Group N (n = 607) served as control. In groups A and B, the abnormalities of spatial VG and QRST values of 12-lead ECG that existed before and 1 day after ablation significantly decreased 1 week after ablation. In group C, spatial VG and QRST values of 12-lead ECG showed no significant changes. The diagnostic ability of spatial VG is almost equivalent to that of the QRST value of ECG in detecting repolarization abnormalities in patients with WPW before and after ablation. We propose a new concept of a "remodeling gradient" directing from the preexcited area to the opposite side of the ventricle as a result of preexcitation-induced electrical remodeling.

Adolescent↗
PubMed2000

Deep white matter lesions on MRI, and not silent brain infarcts are related to headache and dizziness of non-specific cause in non-stroke Japanese subjects.

OBJECTIVE: Silent or asymptomatic cerebrovascular disease is believed to be an important risk factor for symptomatic stroke and vascular dementia. Although non-specific complaints such as mild to moderate headache and/or dizziness may also be caused by silent stroke, which remains a topic of controversy. METHODS: To investigate the relationship between silent brain infarcts and non-specific complaints, we assessed findings on magnetic resonance images using a common protocol in the following three groups of subjects; Group 1:78 subjects with non-specific complaints, Group 2:47 subjects with vascular risk factors, and Group 3:75 normal subjects without any subjective complaints or vascular risk factors. In addition to silent stroke, deep white matter lesions on MRI were also evaluated. All subjects were recruited from 12 institutes of the study group located at various parts of Japan. RESULTS: Silent brain infarcts were demonstrated in 44%, 43%, and 20% of subjects in Groups 1, 2, and 3, respectively. In Group 1, the average number of infarcts per individual who had silent brain infarction was 1.8, which was significantly fewer than 3.8 in Group 2 or 3.5 in Group 3 (p<0.0167). White matter lesions were found in 68%, 49%, and 11% in Groups 1, 2, and 3, respectively, indicating that non-specific complaints are more closely related to deep white matter lesions than to silent infarct lesions. Such white matter lesions were found more frequently in subjects with depressive state than in non-depressed subjects (67% vs. 39%, p=0.0155). CONCLUSION: The present results suggest that deep white matter lesions, rather than silent brain infarcts, appear to be important in producing headache and/or dizziness of non-specific cause and also to be related to the depressive state.

Aged↗
PubMed2000

Slowly progressive dystonia following central pontine and extrapontine myelinolysis.

A 28-year-old woman was hospitalized with dysarthria and oro-mandibular and upper limb dystonia. Approximately 8 years prior to the current admission, the woman became severely hyponatremic due to traumatic subarachnoid hemorrhage-related SIADH. Brain MRIs showed a signal increase in the central pons, thalamus and striatum on T2 weighted images compatible with central pontine and extrapontine myelinolysis. From a few months after that event, dystonia progressed slowly over the subsequent 8 years. We speculate that the particular damage chiefly to the myelin structures by myelinolytic process may have caused an extremely slow plastic reorganization of the neural structures, giving rise to progressive dystonia.

Adult↗
PubMed2000

Inhibitory effect of central calcitonin-gene related peptide (CGRP) on pancreatic secretion in conscious rats.

The inhibitory effect of central administration of calcitonin-gene related peptide (CGRP) on pancreatic secretion stimulated by bile-pancreatic juice diversion was determined in conscious rats. Rats were prepared with separate cannulae for draining bile and pancreatic juice and with a duodenal cannula and an extrajugular vein cannula. In addition, another cannula was stereotactically implanted into the left lateral cerebral ventricle. Rats were placed in restraint cages and experiments were conducted 4 d after the operation without anesthesia. An injection of CGRP (1 nmol/10 microl) into the left lateral cerebral ventricle (i.c.v.) inhibited pancreatic secretion as well as cholecystokinin (CCK) release induced by bile-pancreatic juice diversion. Intravenous infusion of alpha- and beta-adrenergic receptor antagonist, phentolamine and propranolol did not reverse the inhibition of pancreatic secretion. Intravenous infusion of CGRP did not affect pancreatic secretion or plasma CCK concentrations. The inhibitory action of central CGRP (i. c.v.) on pancreatic secretion and CCK release stimulated by bile-pancreatic juice diversion is partially mediated by an alpha-adrenergic mechanism, although its precise mechanism has not been elucidated.

Adrenergic alpha-Antagonists↗
PubMed2000

Vascularization is decreased in pulmonary adenocarcinoma expressing brain-specific angiogenesis inhibitor 1 (BAI1).

Brain-specific angiogenesis inhibitor 1 (BAI1) is a novel angioinhibitory factor. We examined BAI1 gene expression in 48 pulmonary adenocarcinoma specimens by RT-PCR. Vascular density (number and measurement area) was immunohistochemically evaluated in tumor specimens using anti-CD34 monoclonal antibody. BAI1 gene expression was detected in 38 of 48 pulmonary adenocarcinomas (79. 2%). Vascular number and measurement area were significantly decreased in the BAI1-positive pulmonary adenocarcinomas (19.3+/-4. 4/microm2 and 1.7+/-0.6%) as compared with those in the BAI1-negative carcinomas (75.5+/-42.7/microm2 and 5.5+/-1.5%) (Mann-Whitney U-test, p=0.0017). These results suggest that BAI1 expression may inhibit stromal vascularization in pulmonary adenocarcinoma.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Theophylline and cisplatin synergize in down regulation of BCL-2 induction of apoptosis in human granulosa cells transformed by a mutated p53 (p53 val135) and Ha-ras oncogene.

Cisplatin is in common use in ovarian cancer therapy, although it is also implicated in cytotoxicity in normal tissue. We have examined the effect of cisplatin alone and in combination with theophylline, a phoshodiesterase inhibitor, on modulation of Bcl-2/Bax expression and induction of apoptosis in human granulosa cells transformed by stable transfection with mutant p53 plus Ha-ras. Theophylline elicited cell death only at relatively high concentrations with an EC50 of 200 microg/ml. Cisplatin exerted its lethal effect with an EC50 of 7 microM. In the presence of 15 or 50 microg/ml of theophylline (in the range used against asthma in humans), the EC50 for cisplatin was reduced to 2 microM or 1.2 microM, respectively. Using fluorescence-activated cell sorting analysis of DNA stained cells and the terminal deoxy-nucleotide tranferase-mediated dUTP nick end-labeling method, we found that even at concentrations of 0. 3 and 1 microM cisplatin, theophylline at 15 and 50 microg/ml increased the incidence of apoptosis in these cells by 3-5-fold, while theophylline alone induced extremely low apoptosis. Neither drug had any measurable effect on Bax protein expression. In contrast Bcl-2 protein expression levels were markedly reduced by theophylline and cisplatin in a dose-dependent manner. The combination of theophylline and cisplatin resulted in a further dramatic reduction in Bcl-2, under-scoring the pronounced synergy of these two drugs. These observations suggest that suppression of Bcl-2 expression may play an important role in mediating the synergistic effect of cisplatin and theophylline on induction of apoptosis in ovarian cancer cells.

Antineoplastic Agents↗
PubMed2000

[Spinal dermoid cyst secondary to myelomeningocele repair: a case report].

Dermoid and epidermoid tumors arise from the invagination of epidermal elements into the neural tube during the embryonic period. However, many studies have reported that dermoid and epidermoid tumors occur 5 to 10 years after the first operation on myelomeningocele patients. A seven-year-old male with myelomeningocele which had been repaired in his neonatal period, presented leg pain and deterioration of gait disturbance and urinary incontinence. Neuroradiological examinations revealed a spinal dermoid cyst at the repaired myelomeningocele and tethered spinal cord. We removed the tumor and untethered the tethered spinal cord. Postoperatively, the patient's leg pain, gait disturbance and urinary incontinence improved immediately. Inappropriate surgical treatment of spina bifida may cause a second lesion, which leads to tethered-cord syndrome. We suggest that proper surgical treatment, early checkup and neuroradiological evaluations are very important for spina bifida patients who show signs of neurological deterioration. For the best treatment, neurological, urological and orthopedical follow-up study after the first repair operation is necessary.

Child↗
PubMed2000

[A case of intrasellar pure germinoma].

A 19-year-old male presented with progressive loss of vision and diabetes insipidus due to an intra- and suprasellar tumor. Transsphenoidal exploration revealed a pure germinoma. Seven days after the operation, bleeding from the residual tumor caused headache and right occulomotor palsy. The residual tumor and hematoma were removed using pterional approach. The residual tumor disappeared after postoperative irradiation. After 5 months of radiation, multiple lesions due to dissemination of the germinoma were discovered in the suprasellar region. Adjuvant chemotherapy and whole supratentorial irradiation were performed. All lesions regressed completely. Mid-sagittal magnetic resonance image was useful in our patient for differential diagnosis between intrasellar germinoma and pituitary adenoma. Before initiating an operation for intrasellar germinoma, awareness is needed for the fact of postoperative bleeding. We notice that transsphenoidal surgery should be selected for treatment of postoperative bleeding from intrasellar germinoma.

Adenoma↗
PubMed2000

[Rheumatoid arthritis-associated bronchiolitis successfully treated with erythromycin].

A 52-year-old man with a 4-year history of rheumatoid arthritis, and who had an episode of suspected BOOP in early 1994, was admitted to our hospital because of cough and fever. A chest X-ray film on admission showed small patchy infiltrates, and a computed tomographic (CT) scan showed centrilobular nodules and patchy infiltrates with thickened broncho-vascular bundles in both lungs. Transbronchial and thoracoscopic lung biopsies disclosed the coexistence of interstitial pneumonia with BOOP pattern, follicular bronchiolitis, and diffuse panbronchiolitis-like purulent and obliterative bronchiolitis. Due to findings of chronic sinusitis, the patient was treated with erythromycin for 8 weeks, and the abnormal CT shadows regressed. This was an interesting case of various pulmonary lesions associated with rheumatoid arthritis, and successfully treated with erythromycin.

Anti-Bacterial Agents↗
PubMed2000

Content and sulfation pattern of keratan sulfate in hip osteoarthritis using high performance liquid chromatography.

OBJECTIVE: To determine the content and sulfation pattern of keratan sulfate (KS) in synovial fluid (SF) from patients with hip osteoarthritis (OA) and investigate its significance as a marker of cartilage matrix metabolism. METHODS: Hip SF samples were aspirated from 50 patients with OA. KS in the samples was digested to 2 disaccharide isomers, beta-galactosyl-(1-4)-6-0-sulfo-N-acetylglucosamine (L2) and beta-6-0-sulfo-galactosyl-(I-4)-6-0-sulfo-N-acetylglucosamine (LA) by keratanase II. Concentrations of these disaccharide isomers were determined by high performance liquid chromatography (HPLC), and their levels were investigated in relation to radiological stage of disease. RESULTS: Analysis of covariance (age as covariate) showed that the L2 levels in advanced stage OA were significantly lower than in early stage OA (p < 0.0001). L2 levels in terminal stage OA were also significantly lower than in early stage OA (p < 0.0001); however, no significant difference was observed between the L2 levels in advanced and terminal stage OA (p = 0.516). There were no significant differences in the levels of L4, L2 + L4, or the ratio of L4 to L2 at each disease stage. CONCLUSION: The levels of KS related disaccharide isomer vary with severity of disease in hip OA. Analysis of these KS related disaccharide isomers by HPLC provides information on both the content and sulfation pattern of KS in SF, reflecting the metabolism of cartilage aggrecan.

Adult↗
PubMed2000

[A case of posttraumatic severe ventriculitis treated by intraventricular lavage].

A 44-year-old male was admitted in a state of semicoma, tonic convulsion and elevated body temperature nine days after sustaining head injury. He had severe nuchal rigidity. Computed tomography revealed dilation of ventricles and swelling of the brain parenchyma. We performed cerebrospinal fluid (CSF) drainage of both lateral ventricles immediately. The fluid drained from both ventricles was just like pus. We diagnosed the patient's condition as posttraumatic ventriculitis and meningitis. We performed intraventricular lavage (IL) which was our ventricular irrigating technique. IL was repeated until the 7th day postoperatively. The CSF data improved immediately. Continuous spinal drainage (CSD) also was used for CSF drainage from the 7th day postoperatively. The patient recovered without the need for CSF shunt. Some authors have reported the usefulness of continuous intraventricular irrigation (CIVI) for treatment of severe ventriculitis. However, their patients required CSF shunt surgeries. Such shunts are likely to become infected more frequently than routine shunting. Our IL was able to drain pus and inflammatory products in the ventricles before the formation of septations in the ventricles. We emphasize that IL in combination with CSD is able to bring about good results for patients with severe ventriculitis.

Adult↗
PubMed2000

Risk of colorectal cancer in patients with hematologic disease.

BACKGROUND AND AIMS: A relatively large number of patients with multiple myeloma have been reported to develop a secondary malignancy such as cancer of the breast, biliary system or bowel. METHODS: A retrospective study was perfomed in 734 patients with hematologic disease diagnosed at Nippon Medical School Hospital between May 1984 and September 1994 to determine the incidence of colorectal cancer in these patients based on a history review, colonoscopic findings, and surgical or autopsy data. RESULTS: Of the 734 patients, 14 (1.9%) had colorectal cancer; two of 11 patients (18.2%) had pure red cell aplasia; two of 25 patients (8%) had multiple myeloma; and three of 46 patients (6.5%) had aplastic anemia. Patients with pure red cell aplasia, multiple myeloma or aplastic anemia had colorectal cancer at a significantly higher rate compared to those with leukemia (P< 0.005, P< 0.02, P< 0.01, respectively). CONCLUSIONS: It is possible that a relatively large number of patients with pure red cell aplasia, multiple myeloma or aplastic anemia will develop a colorectal cancer.

Aged↗
PubMed2000

[A case of primary Sjögren's syndrome with interstitial pneumonia showing bronchiolitis obliterans organizing pneumonia pattern and lymphofollicular formation].

A 46-year-old woman with a 2-year history of xerostomia, who had had an episode of suspected Sjögren's syndrome in 1995, was admitted to our hospital because of a dry cough. Chest radiography on admission showed ground-glass infiltrates and reticular shadows in both lower lung fields. Primary Sjögren's syndrome was diagnosed by lip biopsy. Video-assisted thoracoscopic lung biopsies revealed the co-existence of interstitial pneumonia with the BOOP pattern and follicular bronchiolitis. Treatment with oral prednisolone improved the symptoms, and reduced the abnormal chest shadows. This was an interesting case of the BOOP pattern in a lung lesion associated with primary Sjögren's syndrome.

Administration, Oral↗