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Biomedical subjects

N Takeda

Publications and source records attributed to N Takeda.

At least 271 records · Page 15Linked to original sources
PubMed1995

Pressure- and thermally-induced reversible changes in the secondary structure of ribonuclease A studied by FT-IR spectroscopy.

Fourier transform infrared (FT-IR) spectroscopy combined with a resolution enhancement technique has been used to characterize pressure and thermal effects on the secondary structure of ribonuclease A. The experiments were performed at pD 7.0 with 50 mg/mL protein solution in D2O buffer. According to the observed changes in the amide I' band, secondary structure elements such as alpha-helices, beta-sheets, and turns are cooperatively disrupted by application of either pressures above 570 MPa at 30 degrees C or temperatures above 60 degrees C at 0.1 MPa. Pressure- and thermally-denatured ribonuclease A are fully unfolded and do not contain any residual secondary structures. Both the structural changes are intrinsically reversible, although the pressure-induced transition shows a hysteresis. It is found that nonnative turn structures are formed prior to the appearance of the native secondary structure in the folding from the pressure-unfolded state. The structural features upon the pressure-induced unfolding are additionally characterized by the interesting behavior of hydrogen-deuterium exchange at high pressure. Most of the backbone amide protons protected at atmospheric pressure, which are involved in the alpha-helices and beta-sheet, are exchanged with solvent deuterons in the pressure range where the two secondary structural elements are virtually identified as intact. There is a possibility that, for ribonuclease A, application of high pressure up to 570 MPa induces such a partially unfolded state as has native-like secondary structure but permits solvent to be highly accessible to the internal regions.

Animals↗
PubMed1995

Femoral peak bone mass and osteoclast number in an animal model of age-related spontaneous osteopenia.

BACKGROUND: SAMP6 was developed as a murine model of age-related spontaneous osteopenia characterized by low peak bone mass. A morphometric study of the growing femur in SAMP6 and sex-matched SAMP2 at 10 days to 4 months of age was done to examine the pathogenic process related to osteopenia. METHODS: Age-related changes in cortical bone thickness, femur score, trabecular bone volume, thickness of epiphyseal growth plate, number of osteoclasts, and osteoclast surface were measured with a computerized image analyzer. Osteoclasts were examined cytomorphometrically after TRAP (tartrate resistant acid phosphatase) staining of the femoral sections. RESULTS: Cortical bone thickness and femur score increased significantly with age, while trabecular bone volume decreased significantly. Comparing mean values of cortical bone thickness, femur score and trabecular bone volume, we noted significantly lower mean values in SAMP6 than in SAMP2 mice. These significant inter-stain differences first became evident in 20-40-day-old mice, but there was no significant difference in thickness of the epiphyseal growth plate between the two strains. The mean values of the number of osteoclasts per unit bone surface length and of the osteoclast surface in SAMP6 were significantly greater than in age- and sex-matched SAMP2. Histograms of distribution of size of osteoclasts of 40-day-old male mice revealed that larger ones were more frequently seen in SAMP6. Furthermore, the ratio of osteoclasts/TRAP positive cells free in the bone marrow cavity was significantly higher in SAMP6 than in SAMP2. CONCLUSION: Activated bone resorption may play a role in the osteopenia seen in SAMP6.

Aging↗
PubMed1995

Vascularized fibular graft for bone reconstruction of the extremities after tumor resection in limb-saving procedures.

We treated 18 patients (8 males and 10 females) with bone or soft tissue tumors in the extremities by vascularized fibular grafts (VFGs). The average age was 29 years. Two had malignant soft tissue tumors in the forearm (angiosarcoma and synovial sarcoma) and the other 16 had bone tumors [osteosarcoma (8), chondrosarcoma (3), angiosarcoma (1), adamantinoma (1), and giant cell tumor (3)]. Affected sites of the bone tumor cases were tibia (5), femur (5), humerus (3), radius (2), and ulna (1). According to the surgical staging system of Enneking et al. 1 patient was in stage III, 12 in IIB, 2 in IB, and 3 in IA. The surgical margin was curative in 5 patients, wide in 9, marginal in 2, and intralesional in 2. One patient died due to lung metastasis although bone union was obtained by the VFGs. Functional results of the bone reconstruction in the remaining 17 patients were evaluated according to the modified scale of Enneking et al. The VFGs resulted in substantial bone unions in all patients except 1. Bone unions in all 17 patients occurred in less than 10 months. Overall clinical results were satisfactory. Based on a 30-point scale overall clinical results ranged from 10 to 30 points with an average of 21 points. Functional evaluation in the upper extremity were, generally, superior to those in the lower extremity. Postoperative complications were 5 metastases (4 in the lung and 1 in the mediastinum) in 4 patients, 1 recurrence, and 2 fractures after obtaining bone union. One patient died from metastasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1995

A new strategy of gene trapping in ES cells using 3'RACE.

"Gene trapping" in embryonic stem (ES) cells is a novel approach to identify a series of genes in mammals concomitant with the production of the corresponding mutant mice. However, this approach is currently unable to identify genes that are not expressed in ES cells. Here we describe a strategy to identify gene trapping clones which is not based on expression of a reporter gene. It uses the neor gene which lacks a polyadenylation signal and has a splice donor signal. Expression of the neor gene as fusion transcripts with the 3' end containing the polyadenylation signal of tagged genes allows the identification of these clones by 3' rapid amplification of the cDNA end in undifferentiated ES cells, even if the genes are not expressed in ES cells. Amplification was observed in about 25% of G418-resistant clones. Sequence analyses suggested the amplifications represent gene trapping events. The feasibility of this approach was further assessed by analysing one clone, PAT-12, in detail.

Amino Acid Sequence↗
PubMed1995

Up-regulation of ferritin heavy chain mRNA expression in the rat skeletal muscle after denervation: detected by means of differential display.

The differential display method was applied to identify gene expression, which is especially up-regulated in denervated skeletal muscle. Total RNA from normal and denervated rat facial muscles (muscles zygomaticus, levator nasolabialis and caninus) was isolated, amplified by polymerase chain reaction (PCR) using certain primers and separated by electrophoresis on a polyacrylamide gel. PCR products, the amounts of which were significantly higher in the operated side than in the control side, were cut out from the gel and sequenced. One of the cDNA fragments obtained in the present study showed 100% identity in nucleotide sequence to the rat ferritin heavy chain (FHC) mRNA. Northern blot analysis and in situ hybridization histochemistry confirmed that FHC mRNA expression was up-regulated after denervation and was distributed throughout whole muscle cell bodies. The biological damage attributed to superoxide and hydrogen peroxide is dependent on the presence of intracellular free iron. Intracellularly, most of the iron that is not metabolized is sequestered in ferritin as a crystalline core of ferric irons (Fe3+). These findings suggest that alterations in the ferritin subunit composition after denervation play an important role in iron metabolism in skeletal muscle cells, resulting in restriction of the biological tissue damage caused by reactive oxygen species.

Animals↗
PubMed1995

Urinary excretion of type I collagen crosslinked N-telopeptides in healthy Japanese adults: age- and sex-related changes and reference limits.

A new immunoassay for measuring urinary excretion of type I collagen crosslinked N-telopeptides (NTx) has been reported to be a specific and sensitive method for assessing bone resorption. We have studied factors affecting biological variations in urinary NTx excretion in a population of 452 healthy Japanese adults, comprising 238 men and 214 women, 20-79 years of age. Urinary NTx excretion increased significantly with age in women (> or = 25 years of age) (r = 0.55, p < 0.0001) and modestly correlated with lumbar bone mineral density (L-BMD) in both sexes (> or = 25 years of age) (r = 0.31, p < 0.0001 for men; r = 0.50, p < 0.0001 for women). Urinary NTx levels in women were significantly higher than in the corresponding male age groups after the fifth decade (p < 0.0001). None of the anthropometric variables (weight, height, and body mass index) showed a linear effect on the urinary NTx excretion independent of age and L-BMD. In women, menopause was reflected by a twofold increase in urinary NTx excretion, from a mean of 28-59 pmol bone collagen equivalents (BCE)/mumol creatinine, and this menopause-related increase persisted for the entire postmenopausal period. In postmenopausal women, the interindividual variations of urinary NTx excretion were much more marked than in men and in premenopausal women. Moreover, in the subgroups of pre- and postmenopausal women, urinary NTx excretion correlated with neither age nor L-BMD. These data show that the major biological factor that modifies urinary NTx level is menopause and suggest that the bone turnover rates in the elderly women are increased, on average, irrespective of bone mineral density.

Absorptiometry, Photon↗
PubMed1995

Favorable course of steroid-responsive nephrotic children with mild initial attack.

The course and prognosis of idiopathic nephrotic syndrome has thus far not been found to be predicted from the severity of the manifestations at the onset. Among 66 steroid-responsive nephrotic children, eight were asymptomatic without edema and identified by chance proteinuria on a urinary screening program. The selectivity index for proteinuria (a clearance ratio of IgG to transferrin) was 0.10 or less in all of the five children examined. All of the eight children responded quickly to the prednisolone therapy. Grades of proteinuria and hypoalbuminemia were lower in the asymptomatic children than in the symptomatic children who presented with edema. Median proteinuria levels were 2.0 versus 4.2 g/day/m2 (P < 0.01), respectively, and mean serum albumin levels were 2.2 +/- 0.3 versus 1.8 +/- 0.4 g/dl (mean +/- SD; P < 0.01), respectively. None of the eight asymptomatic children relapsed for at least one year after completion of the prednisolone treatment, while, in contrast, 30 of 58 symptomatic nephrotic children relapsed during the same one-year period (P < 0.01). These findings suggest that, among steroid-responsive nephrotic children, those with mild manifestations without edema may have a milder disease and show an extremely favorable clinical course.

Child↗
PubMed1995

Molecular biological and quantitative abnormalities of ADP/ATP carrier protein in cardiomyopathic hamsters.

The adenine nucleotide translocator or ADP/ATP carrier protein (AAC) is an integral protein present in the inner mitochondrial membrane, which performs the exchange of cytoplasmic and intramitochondrial ADP and ATP. The myocardial AAC content was studied in J-2-N cardiomyopathic hamsters. The AAC content was found to be significantly decreased in J-2-N hamsters. For molecular biological analysis, hamster AAC (T1 isoenzyme) cDNA was cloned by the plaque hybridization method. This AAC cDNA hybridized specifically with AAC mRNA, so RNA dot-blot hybridization was performed. The highest AAC mRNA level was observed in control hamsters followed by J-2-N hamsters with mild myocardial damage, J-2-N hamsters with severe myocardial damage and Bio 14-6 cardiomyopathic hamsters. These results suggest that a decreased AAC content may contribute to the pathogenesis of cardiomyopathy and that a decrease of AAC mRNA levels may explain the abnormalities of AAC in J-2-N cardiomyopathic hamsters.

Animals↗
PubMed1995

Ovarian teratomas in mice lacking the protooncogene c-mos.

Parthenogenesis has been suggested to be tightly coupled with development of ovarian teratomas. Indeed, ovarian tumors developed in c-mos-deficient female mice, which are characterized by the parthenogenetic activation of oocytes. The tumors appeared at a frequency of 30% between 4 and 8 months of age, and did not develop in younger or older mice. Most of the tumors were benign and consisted of multi-focal cysts most notably with mature ectodermal components, but also with mesodermal and endodermal components. One among 17 tumors observed consisted of extra-embryonic tissues alone, and two bore malignant components with metastasis to peritoneal organs. The results strongly suggest the involvement of c-mos mutations in human germ cell tumors.

Age Factors↗
PubMed1995

[Seroepidemiology of human parvovirus B19 using recombinant VP1 + VP2 particle antigen].

Antibody prevalence to B19 virus in Japan was previously reported with 1973 and 1984 serum collections. Since then we have had two big epidemics of erythema infectiosum in Japan: 1986-87 and 1991-92. In an attempt to estimate how much those epidemics have affected seroprevalence to B19 virus infection, we studied seroepidemiology in three separate areas using a newly developed ELISA system consisting of recombinant VP1 + VP2 particle antigen. Total of 900 sera obtained in 1993 from healthy individuals living in northern, central and southwest parts of Japan were assayed for the presence of anti B19 IgG antibody. In the first, the new assay system was compared with our conventional assay system in which native B19 virus particles were used as antigen. Of 220 serum samples tested, 212 (96.4%) gave same results in both assays. Remaining 8 samples which gave variable results were those of near cut off values. We concluded that this new ELISA system can be recommended for seroepidemiological use. Antibody prevalence rates were 10% (0-4 y), 54% (5-9 y), 59% (10-14 y), 46% (15-19 Y), 38% (20-29 y), 48% (30-39 y), 64% (40-49y) and 76% (50 y-). No gender difference was observed. Comparison of antibody prevalences in 1973, 1984 and 1993 suggested that approximately 10% (about 8 million people) of the total population under 40 years of age acquired immunity to B19 virus during one epidemic period.

Adolescent↗
PubMed1995

[A clinical study of six cases of toxic shock-like syndrome by group A Streptococcus].

We have encountered six cases with toxic shock-like syndrome (TSLS) by Group A Streptococcus since 1978. Every patient had from the onset flu-like symptoms or high fever and immediately developed some of the following clinical signs: hypotension, acute renal failure, disseminated intravascular coagulation (DIC), and adult respiratory distress syndrome (ARDS). Three of the six patients died with rapid clinical courses and three survived. As for the surviving patients, early administration of antibiotics and anti-DIC therapy were effective. Streptococcus pyogenes were isolated from the blood in five of the patients, ascites from another, and necrotizing tissue in one patient. The serovars of the isolated strains were typed as T1/M1 in three, T8 in one, and T28 in another. The toxin-type of the strains were typed as B in four and B + C in one. Though there have been few reports of TSLS before 1992 in Japan, it is supposed that many TSLS cases may have potentially occurred.

Aged↗
PubMed1995

Geographical heterogeneity between Far East and Europe in prevalence of ypm gene encoding the novel superantigen among Yersinia pseudotuberculosis strains.

Yersinia pseudotuberculosis is known to produce a novel superantigen designated Y. pseudotuberculosis-derived mitogen. In the present study, we demonstrated that there was a distinct geographical heterogeneity between the Far East (higher prevalence) and Europe (lower prevalence) in the prevalence of the ypm gene encoding the superantigen among Y. pseudotuberculosis strains.

Antigens, Bacterial↗
PubMed1995

Elevated serum levels of 3-deoxyglucosone, a potent protein-cross-linking intermediate of the Maillard reaction, in uremic patients.

3-Deoxyglucosone (3-DG) has been identified as an intermediate of the Maillard reaction in vitro. We measured serum 3-DG levels using gas chromatography/mass spectrometry and found a marked elevation in serum 3-DG levels in uremic patients compared with healthy subjects. The uremic patients with diabetes showed significantly higher serum concentrations of 3-DG than those without diabetes. 3-DG was demonstrated to be a potent protein-cross-linking agent in the reaction with lysozyme, leading to browning, fluorescence formation and polymerization of the protein by formation of advanced glycation end products (AGE). The increase in serum 3-DG levels in the uremic patients suggests that 3-DG may be responsible for the development of uremic complications by promoting the formation of AGE.

Adult↗
PubMed1995

Hemodynamic adaptations at birth and neonates delivered vaginally and by Cesarean section.

In order to assess the possible influence of differences in delivery mode on cardiovascular adaptation at birth, we measured left ventricular output and its regional distribution in the major organs sequentially using an echographic technique during the first 96 h of life. We studied 27 normal newborns, of whom 15 were delivered vaginally and 12 by cesarean section. We also measured umbilical arterial and venous catecholamine concentrations. The umbilical arterial epinephrine and norepinephrine concentrations in the infants delivered vaginally were significantly greater than those in the infants delivered by cesarean section (epinephrine 1,195 +/- 208 vs. 565 +/- 81 pg/ml, p < 0.05; norepinephrine 11,832 +/- 3,819 vs. 5,153 +/- 1,400 pg/ml, p < 0.05). The left ventricular output and its regional distribution showed a similar pattern in the two groups, and there were no significant differences between them. These results indicate that the capacity of infants delivered by cesarean section to tolerate cardiovascular changes during the early neonatal period is comparable to that in infants delivered vaginally, even though there are significant differences in the catecholamine surge between these groups.

Adaptation, Physiological↗
PubMed1995

A study on urine cotinine for the evaluation of smoking cessation.

Two branch offices of enterprise T in the same city engaged in service and sales were selected at random for this study on the evaluation of smoking cessation education using the urine cotinine concentration (U-Cot) measured by ion pair reversed-phase high performance liquid chromatography (IP-R-HPLC). Branch A conducted a smoking cessation education program; branch B did not. By comparison of the results obtained from questionnaires and U-Cot analyses at both the offices, we investigated the validity of evaluation by U-Cot. The results were as follows: I. Smokers 1. At branch A, a self-reported 20-year-old female non-smoker was confirmed to smoke about 5 cigarettes per day by her high concentration (292.8) of U-Cot at pre-education. 2. At branch A, the self-reported average number of cigarettes smoked daily (ANCSD) at 6 months post-education showed a significant decrease in comparison with that at pre-education. 3. At branch A, U-Cot at post-education showed a significant decrease in comparison with those at 2 weeks, 2 months, and 6 months pre-education in descending order. 4. Two male subjects who were strongly suspected to have submitted a false number of cigarettes smoked prior to urine sampling (NCSPU)/ANCSD self-reports at 6 months post-education were confirmed to have done so by the U-Cot values at the fourth period, which were in excess of 500, and the discrepancy between the ratio ([value at post-education in 6 months] divided by [value at pre-education]) of U-Cot (1.52, 1.47, respectively) and that of NCSPU/ANCSD, (0.00)/0.00). 5. At branch A, discrepancies between the success rate of quitting smoking in self-reported NCSPU/ANCSD at 6 months (17.0%) and in U-Cot (12.2%) were observed. At branch B, no such discrepancies were observed. 6. At branch A, office workers at 6 months post-education who had, but not those who had not, previously considered the health damage caused by smoking showed a significant decrease in NCSPU/ANCSD, and also in U-Cot at 2 weeks, 2 months and 6 months post-education. At branch B, no such differences were observed. 7. At branch A, office workers at 6 months post-education who had previously considered quitting smoking showed a significant decrease in NCSPU/ANCSD, and also in U-Cot at 2 weeks, 2 months and 6 months post-education. Those who had not previously considered quitting showed a significant decrease in ANCSD, but not in NCSPU or U-Cot.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗