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Biomedical subjects

Y Takano

Publications and source records attributed to Y Takano.

At least 109 records · Page 6Linked to original sources
PubMed2000

Age-related variations of elements as compared among optic, radial, and sciatic nerves.

To elucidate changes of peripheral nerves with aging, the authors studied age-related changes of element contents in the optic, radial, and sciatic nerves by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of seven men and seven women, ranging in age from 61 to 97 yr. The contents of phosphorus and sulfur remained constant through ages 61 to 97 yr in three nerves, the optic, radial, and sciatic nerves. It was found that there were age-related differences in calcium content among the optic, radial, and sciatic nerves: The calcium content of the optic nerve increased progressively with aging; in the radial nerve, it was hardly changed with aging; in contrast, the calcium content of the sciatic nerve decreased gradually with aging. In addition, it was found that in the radial nerve there were moderate correlations between age and zinc or sodium content, whereas significant correlations between age and the content of silicon or iron were found in the sciatic nerve. Furthermore, there was a correlation between the silicon and iron contents in the sciatic nerves.

Aged↗
PubMed2000

Age-dependent changes of elements in human trachea.

To elucidate compositional changes of human trachea by aging, element contents in tracheae were determined by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of seven men and seven women, ranging in age from 61 to 97 yr. The sulfur content of the tracheae decreased gradually with aging. In regard to calcium and phosphorus, both the contents increased to about threefold amounts in their seventies compared with those in their sixties, and decreased thereafter. The contents of calcium and phosphorus were the highest in their seventies. Therefore, it is likely that surplus calcium released from bones is deposited temporally in the trachea, and the deposits are released from the trachea at older age. Based on our results of human cartilages, there are two types in regard to calcium accumulation: The first type is that calcium accumulation occurs progressively with aging; the second one is that calcium accumulation becomes the highest in the seventies or eighties, and decreases thereafter. Therefore, the trachea belongs to the second type. Furthermore, the magnesium content remained constant through the age range.

Aged↗
PubMed2000

Time-related changes of developing enamel crystals after exposure to the tissue fluid in vivo: analysis of a subcutaneously implanted rat incisor.

To investigate the effects of tissue fluid on the growth of enamel crystals, upper and lower incisors extracted from 3-week-old Wistar rats were removed of the enamel organ, implanted subcutaneously in the dorsal portion of animals from the same litter, and harvested at 72 h or 1 week after implantation. The grafts were chemically fixed with surrounding tissues and prepared for light and electron microscopy, X-ray microanalysis, or for the immunohistochemistry of amelogenin. Mineralization of implanted enamel layers was examined by contact X-ray microradiography. The immunoreactivities for 25 kD amelogenin in immature enamel decreased sequentially, starting from the surface to the deeper layers; by 1 week after implantation, no positive reactivities remained in the entire enamel layers at the stages of matrix formation and early maturation. In accordance with the loss of enamel proteins, immature enamel gained mineral density until it attained higher radio opacity than that of the adjacent dentin by 1 week. In contrast, the radio opacity of the full thickness of the enamel at early maturation remained low except for a superficial thin layer. Electron microscopy revealed no sign of growth of original enamel crystals, but showed heavy precipitation of electron-dense fine granules of calcium phosphate in all layers of the secretory enamel and the superficial layer of enamel at early maturation, which showed high radio opacity. The Ca/P ratio and electron diffraction patterns of the granular materials precipitated between intrinsic enamel crystals indicated the property of hydroxy apatite or octacalcium phosphate though a characteristic ribbon-like profile of enamel crystals was lacking. These data indicate that the enamel organ blocks exogenous mineral precipitates in growing enamel during the stage of matrix formation and plays an essential regulatory role for fine enamel crystallites to grow into large hexagonal crystals.

Amelogenin↗
PubMed2000

Time-related changes in periodontal mechanoreceptors in rat molars after the loss of occlusal stimuli.

The effect of a loss of occlusal stimuli upon the distribution and structure of the periodontal mechanoreceptors of the rat mandibular molar was examined after extracting opposing molars. The hypofunctional periodontal ligament narrowed significantly two weeks after tooth extraction, associated with an altered morphology of the Ruffini endings that showed typical dendritic profiles in normal controls. At four weeks and later periods after extraction, the Ruffini endings-including those without light microscopic changes demonstrated unusual ultrastructural features such as the eccentric localization of mitochondria along the axonal membrane and loss of other cell organelles, unusual elongation of axonal microprojections, or a deep invagination of the Schwann sheath into the axoplasm. Immunoreactivity for the growth-associated protein-43 (GAP-43) in the Ruffini endings was restricted to the Schwann element in both the normal and hypofunctional periodontal ligament, but the reaction was weaker and even negligible in some cases in the latter ligament. The present results suggest that occlusal stimuli are essential for maintaining the structural integrity of the periodontal ligament, including that of periodontal mechanoreceptors. A decreased immunoreactivity for GAP-43 in the Schwann sheaths supports the notion of a possible functional alteration in the Ruffini endings that showed no structural abnormality.

Acid Phosphatase↗
PubMed2000

[Does negative priming occur by rotated characters?].

We conducted three experiments in order to investigate the effect of stimulus orientation on negative priming (NP). Using the picture naming task, Murray (1995) reported the occurrence of semantic NP by rotated distractors. As the rotation of picture stimuli seems to have little effect to reduce distractor interference, in the present study we used the character (katakana) identification task to ensure the effect of stimulus rotation. When the distractors were rotated (180 degrees), no NP was observed whether the targets were upright (Experiment 1) or rotated (Experiment 2). On the other hand, significant NP was observed when the distractors were upright and the targets were rotated (Experiment 3). These results suggest that the inhibitory mechanism of attention may not operate on the rotated distractor characters.

Adult↗
PubMed2000

The value of pre-operative diagnostic procedures for cervical involvement in uterine corpus carcinoma.

OBJECTIVE: To assess the value of procedures for pre-operative diagnosis of cervical involvement of uterine corpus carcinoma. MATERIALS AND METHODS: Four diagnostic procedures, including cervical cytology, endocervical curettage (ECC), magnetic resonance imaging (MRI), and hysteroscopy, were performed for diagnosis of cervical involvement in 60 patients with uterine corpus carcinoma. The preoperative diagnosis based on results obtained using by each procedure was retrospectively compared with the diagnosis based on histological examination of surgical specimens. Data were analyzed according to the standard definition of sensitivity, specificity, positive predictive value and negative predictive value. RESULTS: Cervical involvement was confirmed in 18 patients (30%). ECC showed high sensitivity (90.9%) and specificity (88.9%). Cervical cytology showed high specificity (88.6%). MRI showed very high specificity (99.2%) and high sensitivity (88.5%) in cases with cervical stromal invasion. CONCLUSION: Cervical cytology and MRI are useful for excluding cervical involvement. ECC is useful for positive diagnosis. MRI may be useful for cases with stromal invasion. The use of a combination of several procedures is essential for obtaining an accurate diagnosis of cervical involvement in cases of uterine corpus carcinoma.

Adult↗
PubMed2000

Myxoid leiomyosarcoma of the uterus.

A 70-year-old, menopausal Japanese woman with large uterine tumor underwent total hysterectomy. Microscopic examination revealed a myxoid leiomyosarcoma with 5 to 6 mitoses/10 high power field (HPF). Immunohistochemically, the tumor cells reacted with desmin, suggesting that they are derived from uterine smooth muscle cells. The patient was treated with the combination chemotherapy consisting of cisplatin, adriamycin and cyclophosphamide, and she has been free from disease for 70 months after the operation.

Aged↗
PubMed2000

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1998). I. Susceptibility distribution].

The frequencies of bacterial isolation and susceptibilities to antimicrobial agents were investigated on 538 bacterial strains isolated from patients with urinary tract infections (UTIs) in 9 hospitals during the period of June 1998 to May 1999. Of the above bacterial isolates, Gram-positive bacteria accounted for 30.3% and Gram-negative bacteria accounted for 69.7%. Susceptibilities of several isolated bacteria to antimicrobial agents were as follows; against Enterococcus faecalis isolated from patients with UTIs, vancomycin (VCM), ampicillin (ABPC) and imipenem (IPM) had strong activities. Among E. faecalis strains, those with low susceptibilities to all drugs have increased in 1998, compared with those in 1997. VCM showed the highest activity against MRSA isolated from patients with UTIs. The MICs of VCM for all 34 strains were equal to or lower than 2 micrograms/ml. Arbekacin (ABK) was also active against MRSA with the MIC90s of 2 micrograms/ml. Against Escherichia coli and Klebsiella pneumoniae, all drugs except penicillins were active. Particularly, meropenem (MEPM) showed the highest activity with the MICs of 0.125 micrograms/ml or below. Almost all the drugs except minocycline (MINO) showed high activities against Proteus mirabilis. Against Pseudomonas aeruginosa, all drugs were not so active, with the MIC90s of 16 micrograms/ml or above. MEPM, IPM and gentamicin (GM) showed high activities against Serratia marcescens. Generally, it seemed that resistant strains of S. marcescens had decreased since 1996.

Anti-Bacterial Agents↗
PubMed2000

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1998). II. Background of patients].

Clinical background was investigated on 449 patients with urinary tract infections (UTIs) from whom 591 bacterial strains were isolated in 9 hospitals during the period from June, 1998 through May, 1999. About distribution of age and sex of patients and type of infections, among males, patients less than 50 years old were few, and uncomplicated UTIs without indwelling catheters was most frequent. Among females, patients less than 20 years old were few, and uncomplicated was most frequent. Escherichia coli was the most frequently isolated in uncomplicated UTIs, and the higher the ages of patients, the higher were became the isolation frequencies of Enterococcus faecalis, Proteus spp. and Klebsiella spp. In complicated UTIs with indwelling catheters and without indwelling catheters, the types of pathogens had no relation with ages. The complication of infections had decreased E. coli but that had increased Proteus spp., Pseudomonas aeruginosa and Staphylococcus aureus. Until last year, use of antibiotics had decreased pathogens isolated from patients with uncomplicated UTIs drastically in our study. But, pathogens isolated after antibiotics had increased in 1998. As for surgical procedures and types of causative organisms in UTIs, E. faecalis were more isolated when surgical procedures were experienced, and E. coli were more isolated when they were not in uncomplicated and complicated UTIs without indwelling catheters. In complicated UTIs with indwelling catheters, types of causative organisms had no relationship with surgical procedures.

Adult↗
PubMed2000

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (1998). III. Secular changes in susceptibility].

Susceptibilities to various antimicrobial agents were examined for Enterococcus faecalis, Staphylococcus aureus, Echerichia coli, Klebsiella spp. and Pseudomonas aeruginosa that were isolated from patients with urinary tract infections (UTIs) in 9 hospitals during June 1998 to May 1999, and the results were compared with those obtained during the same period from 1990 to 1997 in uncomplicated UTIs and complicated UTIs. Among E. faecalis strains, those with low susceptibilities to almost drugs have increased in the latest period. All 5 S. aureus strains isolated from uncomplicated UTIs were the most susceptible to gentamicin (GM). Over 50% of S. aureus strains isolated from complicated UTIs were susceptible to GM, and on the contrary the resistant strains have increased with the MIC90 of 256 micrograms/ml or above. Among S. aureus strains isolated from complicated UTIs, those with low susceptibilities to arbekacin (ABK) have increased in the latest period compared to those during period of 1996-1997, and the MIC90s of them have changed into the lower state from 1 microgram/ml in 1996-1997 to 4 micrograms/ml in 1998. S. aureus strains have continued high susceptibilities to vancomycin (VCM). The susceptibilities to minocycline (MINO) of E. coli showed MIC90: 4 micrograms/ml in 1997, but those have returned in the latest period in uncomplicated UTIs. The MIC90s of ofloxacin (OFLX) to E. coli isolated from uncomplicated and complicated UTIs have been lower 2-3 classes in the latest period than those in 1997. Among Klebsiella spp. strains isolated from uncomplicated UTIs, those with low susceptibilities to almost cephems had increased in 1997, but few of them were detected in the latest study. The sensitive strains of P. aeruginosa to almost drugs have increased during the latest period. The MIC50s of cefozopran (CZOP) and OFLX against P. aeruginosa were the best in our history. The sensitive strains of P. aeruginosa to ceftazidime (CAZ) have increased and its percentage was 30%. Piperacilline (PIPC), cefoperazone (CPZ), GM and OFLX resistant P. aeruginosa strains have increased in the latest period.

Anti-Bacterial Agents↗
PubMed2000

[Renocolic fistula: a case report].

A 78-year-old woman had disregarded pneumaturia since April 1998. In March 1999, computed tomography and barium enema were done to examine anemia and positive fecal occult blood, revealing a left renocolic fistula and bilateral renal stones. Intravenous pyelography revealed a left staghorn calculus, non-functioning kidney, and right partial staghorn calculus. Urinalysis showed pyuria and the culture grew Proteus vulgaris and Klebsiella oxytoca. Smear and culture of the urine were negative for acid-fast bacilli. In consideration of the patient's age and conservation of right renal function, right pyelolithotomy was performed first. Three weeks later, left nephrectomy and partial colectomy were done. The postoperative course was uneventful. A renocolic fistula is relatively rare and to our knowledge there have been 37 cases reported in Japan, including our case. Surgery is the main therapy and was performed in 31 patients. Among them, surgery was not curative in 1 and 5 died of postoperative complications. Thus, surgery is not safe in all cases. However, despite her age and bilateral renal dysfunction, our patient was successfully operated on.

Aged↗
PubMed1999

Roles of nitric oxide in the spinal cord in cardiovascular regulation in rats.

The roles of nitric oxide (NO) in the spinal cord in regulation of blood pressure were examined in anesthetized rats. Intrathecal (i.t.) injection of an inhibitor of NO synthase (NOS), N(omega)-nitro-L-arginine methylester (L-NAME), caused marked dose-dependent increase in the blood pressure. The pressor response to L-NAME was attenuated by pretreatment with L-arginine (10 micromol, i.t.). Pretreatment with the ganglionic blocker pentolinium (10 mg/kg, i.v.) and alpha1- and beta-adrenoceptor antagonists significantly inhibited the pressor response induced by L-NAME. The pressor responses to L-NAME was blocked by pretreatment with the selective N-methyl-D-aspartate (NMDA) receptor antagonist DL-2-amino-5-phosphonovaleric acid (AP-5) (50 nmol, i.t.), but not by pretreatment with a non-NMDA receptor antagonist, 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX). In addition, the pressor response to L-NAME was reduced by spinal cord transection. These results suggest that L-NAME causes activation of the sympathetic nervous system by reduction of NO in the spinal cord, and that this reduction of NO by L-NAME may activate glutamatergic neurons in the medulla oblongata.

Animals↗
PubMed1999

Cyclin D2, but not cyclin D1, overexpression closely correlates with gastric cancer progression and prognosis.

Expression of cyclins D1 and D2, as well as cyclin-dependent kinase 4 (cdk4), was investigated by means of immunohistochemistry in 455 gastric cancer cases. Additional western blotting was performed for four breast cancer and four gastric cancer cell lines and 35 fresh frozen gastric cancer samples, to confirm the cyclin D1, D2, and cdk4 data. Cyclin D1 was restricted to the nucleus of cancer cells with a few exceptions, whereas cyclin D2 was present in both cell compartments, but predominantly in the cytoplasm. Cdk4 was intermediately expressed. Cyclin D1 was overexpressed in 93 cases (20.4 per cent) and cyclin D2 in 105 (23.0 per cent). In the cyclin D2 cases, this correlated with greater age (p=0.0004), better differentiation (p=0.0023), greater depth of cancer invasion (p=0. 003), the presence of lymph node metastasis (p=0.0014), vascular invasion by cancer cells (p< 0.0001), and poor prognosis (p< 0.0001), while cyclin D1 did not correlate with any of these except age (p=0.00193). Multivariate analysis revealed cyclin D2 overexpression to be an independent prognostic factor, in addition to depth of cancer invasion and lymph node status. Cdk4 overexpression was linked to cyclin D1, but not cyclin D2 overexpression. The results indicate that cyclin D2 up-regulation plays an important role in the progression and prognosis of gastric cancer independently of cdk4, whereas cyclin D1 overexpression does not.

Adult↗
PubMed1999

Elastic anisotropy and collagen orientation of osteonal bone are dependent on the mechanical strain distribution.

There is evidence that the collagen microarchitecture of bone is influenced by mechanical stresses or strains. We hypothesized that peak functional strains correlate with the elastic anisotropy and collagen orientation of bone tissue and that the bone anisotropy might be changed by altering the strain patterns in canine radii for 12 months. We tested these hypotheses in studies using nine adult foxhounds. The baseline group (n = 3) had three rosette strain gauges placed around the midshaft of the radius, and strain distributions were measured during walking. The osteotomy group (n = 3) had 2 cm of the ulna surgically removed, and the sham group (n = 3) received a sham osteotomy. The osteotomy and sham groups were allowed free movement in cages with runs for 12 months, after which strain distributions were measured on the radii during walking. Bone-tissue anisotropy and collagen architecture were measured in radii from which the in vivo longitudinal strain patterns had been measured. The collagen birefringence patterns were measured with use of a circularly polarized light technique, and the elastic anisotropy of the bone, mineral, and collagen matrix was evaluated with a novel acoustic microscopy technique. Peak longitudinal strains in the radius correlated with the normalized longitudinal structure index (a polarized light measure of collagen birefringence) and the tissue anisotropy ratio. The average anisotropy ratio was 1.28+/-0.01 in the posterior (compressive) cortex and 1.43+/-0.01 in the anterior (tensile) cortex (these values are significantly different at p < 0.0001). The ulnar osteotomy changed the strain pattern on the radius, causing increased tensile strains in the medial cortex by more than 5-fold that were associated with a significant increase in the anisotropy ratio in the bone tissue. The longitudinal structure index was strongly correlated (r = 0.62, p < 0.005) with the anisotropy ratio of demineralized bone but was not correlated with that of deproteinized bone; this indicates that it reflects collagen fibril orientation in the bone matrix. These results indicate that mechanical strains affect both collagen and mineral microarchitecture in bone tissue, i.e., tensile strains are associated with increased tissue anisotropy and compressive strains, with decreased anisotropy.

Animals↗
PubMed1999

Age-related changes of elements in human anterior cruciate ligaments and ligamenta capitum femorum.

To elucidate compositional changes of human ligaments by aging, the content of elements in anterior cruciate ligaments (ACLs) and ligamenta capitum femorum (LCFs) was analyzed by inductively coupled plasma-atomic emission spectrometry. The subjects consisted of 11 men and 7 women, ranging from 59 to 91 yr of age. With regard to the content of elements, the content of sulfur and iron was significantly higher in the LCFs than in the ACLs. It was found in the ACLs that the content of sulfur decreased gradually with aging, whereas the content of calcium, phosphorus, and magnesium increased progressively with aging. On the other hand, it was found in the LCFs that the content of magnesium decreased gradually with aging, where as the content of phosphorus increased progressively with aging. The common finding that the content of phosphorus increased with aging, but the content of iron decreased, was obtained in the ACL and LCF. Regarding sexual difference, it was found in both the ACLs and LCFs that the content of phosphorus was higher in women's ligaments than in men's.

Aged↗
PubMed1999

Age-related changes of elements in the human articular disk of the temporomandibular joint.

To elucidate compositional changes of the articular disk (AD) of the temporomandibular joint (TMJ) by aging, elements of the ADs resected from 18 cadavers were determined by inductively coupled plasma atomic-emission spectrometry. It was found that calcium contents of ADs in TMJs increased progressively with aging, whereas the sulfur contents of the ADs decreased slightly with aging. Regarding the content of phosphorus, the contents increased progressively with aging. The study revealed that age-related changes of calcium contents in the ADs of TMJs were similar to those in women's pubic symphyses, but not those in intervertebral disks and menisci.

Aged↗
PubMed1999

Treatment with active vitamin D metabolites and concurrent treatments in the prevention of hip fractures: a retrospective study.

UNLABELLED: The purpose of this study was to determine the effect of treatment with active vitamin D metabolites and other concurrent medication on the prevention of hip fractures in elderly women. We inspected the medical records of the entire female population over 65 years of age on Sado Island, and followed a total of 11,377 women for a 3-year period. Of these, 1208 osteoporotic patients were treated with either 1,25-(OH)2D3 or 1 alpha-(OH)D3. The 765 patients who received the minimum effective dosage for more than 6 months made up the 'treatment group'. Nearly half these patients were also treated with either calcitonin or calcium. The 443 patients who received treatment with active vitamin D metabolites, but at a dosage or for a duration that did not meet the criteria for the treatment group, were deemed the 'ineffective group'. The remaining 10,169 women were the 'non-treatment group'. Fractures in the non-treatment group occurred at a rate of 39.8 fractures/10,000 person-years. The rate in the treatment group was 10.8, which was significantly lower (p = 0.039). Interestingly, the fracture rate after ceasing treatment was 52.1, which was significantly higher (p = 0.002) than the rate in patients receiving treatment. No statistical differences in the fracture rate were found between the ineffective, non-treatment and post-treatment groups. A reduction in the fracture rate was observed only in the treatment subgroup that did not also receive calcitonin (p = 0.042), and not in the subgroup that also received calcitonin therapy (p = 0.333). However, there was no statistical difference in the hip fracture rates between these two subgroups (p = 0.157) and the actual number of fractures was minimal (0 vs 2). Therefore, in this study, the advantage of treatment with active vitamin D alone over combined treatment with calcitonin seems to be marginal. IN CONCLUSION: (1) treatment with active vitamin D metabolites and with combined therapy may be marginally effective in preventing hip fractures, and (2) stopping the treatment clearly increases the risk of hip fractures.

Adjuvants, Immunologic↗