Biomedical subjects

A Kobayashi

Publications and source records attributed to A Kobayashi.

At least 127 records · Page 7Linked to original sources

PubMed2000

The pharmacokinetics of trinitroglycerin and its metabolites in patients with chronic stable angina.

AIMS: To study the pharmacokinetics of trinitroglycerin (GTN) and its four metabolites in angina patients during their transient use of transdermal GTN tape following intravenous administration of GTN. METHODS: Four patients received a GTN tape following intravenous administration of 0.1 microg kg-1 min-1 GTN, and the other four patients received two GTN tapes following intravenous administration of 0.2 microg kg-1 min-1 GTN. RESULTS: Plasma concentrations of GTN in both groups during tape application showed a slight decrease for the hour after the application of the tape and then were con- stant for 24 h. In contrast, the concentrations of dinitroglycerins (GDNs) and mononitroglycerins (GMNs) depended on the duration of previous intravenous administration of GTN. Neither significant cardiovascular changes nor undesirable complications were observed during the study. CONCLUSIONS: The results suggest that appropriate replacement of intravenous GTN administration with transdermal tape application could maintain a therapeutic GTN level.

Aged↗

PubMed2000

A novel hemocyte-specific membrane protein of Sarcophaga (flesh fly).

Extensive tissue remodeling takes place during metamorphosis of holometabolous insects. It has been shown that hemocytes play crucial roles in the recognition and elimination of apoptotic cells and larval tissue fragments produced during metamorphosis. We report the immunoaffinity purification, cDNA cloning, and characterization of a prepupal hemocyte membrane protein of Sarcophaga (flesh fly) with a molecular mass of 120 kDa. This protein is a novel type I transmembrane protein with 18 repeats of an epidermal growth factor-like domain in the predicted extracellular region. Expression of the protein was restricted exclusively to prepupal hemocytes. This protein is suggested to be a scavenger receptor for tissue remodeling.

Amino Acid Sequence↗

PubMed2000

Assessment of disease activity and extent by magnetic resonance imaging in ulcerative colitis.

BACKGROUND: We determined whether magnetic resonance imaging (MRI) could determine the activity and site of involvement in ulcerative colitis. METHODS: Colonoscopy, double-contrast barium enema and gadodiamide-enhanced MRI were performed prospectively in six patients with ulcerative colitis, including three females aged 10-22 years, both in the active and the remission stages. RESULTS: Characteristic findings of MRI in the active stage of ulcerative colitis were loss of haustral markings and thickening and contrast enhancement of the colonic wall. In five of six patients, the site of disease distribution determined by MRI was in accordance with that determined by colonoscopy. CONCLUSIONS: Gadodiamide-enhanced MRI is a safe and useful method of determining disease activity and extent in patients with ulcerative colitis.

Adolescent↗

PubMed2000

Histologic and mechanical evaluation of impacted morcellized cancellous allografts in rabbits: comparison with hydroxyapatite granules.

The bioactivity and mechanical properties of morcellized allografts and hydroxyapatite (HA) granules were evaluated in a rabbit model. Allografts were replaced by viable trabecular structures within 8 weeks. The yield strength and stiffness of allografts were within normal cancellous bone levels by 3 weeks and were maintained afterward. The amount of newly formed bone around HA granules was comparable to that around allografts. The yield strength and stiffness of HA granules were significantly higher than those of allografts at 3 and 12 weeks. Allografts offer the advantage of being replaced by host-bone without significant deterioration in mechanical properties over the course of remodeling. HA granules can also be used for a bone substitute given their bioactivity in bone conduction and superiority in mechanical properties to allografts.

Animals↗

PubMed2000

Association between parathyroid hormone (PTH)/PTH-related peptide receptor gene polymorphism and the extent of bone mass reduction in primary hyperparathyroidism.

Genetic contributions to bone mineral density (BMD) and bone turnover are well known. In the present study, we analyzed the relationship between polymorphism of parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor gene existing in exon M7 and the clinical characteristics of primary hyperparathyroidism (pHPT). PTH/PTHrP receptor genotypes were analyzed in 92 pHPT patients by direct sequence to determine whether nucleotide 1417 of the cDNA was C or T. BMD levels at the lumbar spine and at the radius before and one year after parathyroidectomy, as well as serum levels of calcium, phosphorus, alkaline phosphatase (ALP) and intact PTH were measured. Although there were no significant differences in serum levels of calcium, phosphorus and intact PTH, ALP was significantly lower in the CT genotype compared with the TT genotype. BMD level at the radius was significantly higher in the CT genotype than in the CC genotype. Moreover, an increase in radial BMD one year after parathyroidectomy was significantly less in CT genotype than two other genotypes (CC, TT). The present study is the first to indicate that the polymorphism of PTH/PTHrP receptor gene is closely related to the extent of bone mass reduction in pHPT and that this polymorphism would be one of the genetic factors responsible for the severity of the pathological state of pHPT.

Alkaline Phosphatase↗

PubMed2000

Molecular cloning and characterization of SRAM, a novel insect rel/ankyrin-family protein present in nuclei.

Previously, we purified a 59-kDa protein that binds to the kappaB motif of the Sarcophaga lectin gene. Here we report its cDNA cloning and some of its characteristics as a novel member of the Rel/Ankyrin-family. This protein, named SRAM, contained a Rel homology domain, a nuclear localization signal and 4 ankyrin repeats, but lacked the Ser-rich domain and PEST sequence that Relish contained. We found that SRAM was localized in the nuclei of NIH-Sape-4 cells, which are an embryonic cell line of Sarcophaga. The Sarcophaga lectin gene promoter containing tandem repeats of the kappaB motifs was activated in NIH-Sape-4 cells. In Drosophila mbn-2 cells, Dif alone activated this reporter gene and a cooperative effect was detected when SRAM and Dif were co-transfected, although SRAM alone did not activate it. This is the first report of a Rel/Ankyrin molecule that exists in the nuclei.

Amino Acid Sequence↗

PubMed2000

A half-type ABC transporter TAPL is highly conserved between rodent and man, and the human gene is not responsive to interferon-gamma in contrast to TAP1 and TAP2.

TAPL is a half-type ABC transporter with sequence similarity to TAP1 and TAP2 that is transcribed in various rat tissues [Yamaguchi, Y., Kasano, M., Terada, T., Sato, R., and Maeda, M. (1999) FEBS Lett. 457, 231-236]. Primary structures of the human and mouse orthologous counterparts were deduced from cDNAs cloned by means of polymerase chain reaction, and they were compared with that of the rat. The mammalian TAPLs (rat, mouse, and human) are highly conserved, since about 95% of the amino acid residues are identical between rodents and man. Phylogenetic analysis demonstrated that the evolutional rate of TAPL is much slower than those of TAP1 and TAP2, although TAPL could have diverged from an ancestor of TAP1 or that of TAP1 and TAP2. The TAPL-GFP fusion protein transiently expressed in Cos-1 cells was co-localized with PDI, suggesting that TAPL is inserted into endoplasmic reticulum membrane. The conservation of the peptide-binding motifs of TAP proteins in TAPL raises the possibility that the TAPL might be a peptide transporter. The gene for human TAPL is assigned to chromosome 12q24.31-q24.32, while those for TAP1 and TAP2 are located at the MHC locus of chromosome 6p21.!3. Furthermore, the transcription of TAPL gene is not responsive to interferon-gamma, in contrast to TAP1 and TAP2. These results indicate that the gene regulation of TAPL is different from those of TAP1 and TAP2.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2000

Thermological study of drilling bone tissue with a high-speed drill.

OBJECTIVE: To perform a detailed quantitative analysis of the effect of intermittent drilling and irrigation to lower the temperature during high-speed drilling. METHODS: We examined the thermal changes for 15 bone flaps while drilling a 7- x 7-mm area for 18 seconds and a specific point for 9 seconds, under the following conditions: continuous or intermittent drilling; with a fluted steel or a diamond ball cutter; without or with irrigation, with room temperature or cold (8 degrees C) Ringer solution. RESULTS: The maximum temperature during continuous drilling with a diamond cutter (or steel cutter) was 82.4 +/- 1.3 degrees C (55.2 +/- 1.0 degrees C) without irrigation, 42.5 +/- 1.2 degrees C (35.4 +/- 0.9 degrees C) with room temperature Ringer irrigation, and 22.5 +/- 1.4 degrees C (21.6 +/- 0.3 degrees C) with cold Ringer irrigation, whereas that during intermittent drilling was 66.1 +/- 1.2 degrees C (35.6 +/- 0.8 degrees C), 35.0 +/- 0.8 degrees C (25.4 +/- 0.7 degrees C), and 21.5 +/- 0.6 degrees C (21.8 +/- 0.4 degrees C), respectively. During continuous drilling of a specific point, the radius of the concentric isothermal line for 43 degrees C (thermal threshold for neurons) was 3.6 +/- 0.8 mm with a steel cutter, and it was 8.1 +/- 0.3 mm with a diamond cutter. The radius was 4.2 +/- 0.8 mm during intermittent drilling with a diamond cutter, and it was 4.0 +/- 0.1 mm during continuous drilling with room temperature Ringer irrigation. Intermittent drilling with cold Ringer irrigation kept the temperature, even at the center of the drilled area, below 20 degrees C. CONCLUSION: Intentional intermittent drilling with irrigation reduces temperature elevation and its expansion. These procedures are necessary for safe drilling, especially with a diamond burr. Although cold irrigation can minimize temperature elevation, its substantial effect on nerves or other structures needs to be elucidated.

Adult↗

PubMed2000

Association of decreased calcium-sensing receptor expression with proliferation of parathyroid cells in secondary hyperparathyroidism.

BACKGROUND: The down-regulation of both calcium-sensing receptor (CaSR) and vitamin D receptor (VDR) in parathyroid (PT) glands of secondary hyperparathyroidism (HPT) caused by chronic renal failure has been associated with PT hormone hypersecretion as well as PT hypergrowth. To clarify the predominance of decreased expression of CaSR and VDR in the high proliferative activity of PT glands, we examined the relationship between the expression of both receptors and proliferative activity in human PT glands. METHODS: Serial sections of 56 PT glands, including 52 glands from secondary HPT and 4 normal PT glands resected together with thyroid carcinoma, were examined immunohistochemically with specific antibodies against CaSR, VDR, and Ki67. The Ki67-positive cell number was counted and expressed as the Ki67 score. The CaSR and VDR expressions were semiquantitatively analyzed. RESULTS: The expressions of both CaSR and VDR were markedly decreased in PT glands of secondary HPT, while the Ki67 score was significantly higher than it was in normal controls. When hyperplastic glands were classified into two subgroups, with [N(+)] or without [N(-)] nodular formation, CaSR expression was significantly decreased in N(+), while VDR expression was not different. Multiple regression analyses revealed that the decreased expression of CaSR could contribute significantly to the high proliferative activity, even if VDR expression was taken into account. CONCLUSION: The decrease in CaSR expression is associated with the high proliferative activity of PT glands in secondary HPT, independently of the decreased VDR expression. These findings provide a new insight into the pathogenesis of PT hyperplasia, which is refractory to vitamin D therapy in patients with severe secondary HPT.

Cell Division↗

PubMed2000

A combinatorial code for gene expression generated by transcription factor Bach2 and MAZR (MAZ-related factor) through the BTB/POZ domain.

Bach2 is a B-cell- and neuron-specific transcription repressor that forms heterodimers with the Maf-related oncoproteins. We show here that Bach2 activates transcription by interacting with its novel partner MAZR. MAZR was isolated by the yeast two-hybrid screen using the BTB/POZ domain of Bach2 as bait. Besides the BTB/POZ domain, MAZR possesses Zn finger motifs that are closely related to those of the Myc-associated Zn finger (MAZ) protein. MAZR mRNA was coexpressed with Bach2 in B cells among hematopoietic cells and in developing mouse limb buds, suggesting a cooperative role for MAZR and Bach2 in these cells. MAZR forms homo- and hetero-oligomers with Bach2 through the BTB domain, which oligomers bind to guanine-rich sequences. Unlike MAZ, MAZR functioned as a strong activator of the c-myc promoter in transfection assays with B cells. However, it does not possess a typical activation domain, suggesting a role for it as an unusual type of transactivator. The fgf4 gene, which regulates morphogenesis of limb buds, contains both guanine-rich sequences and a Bach2 binding site in its regulatory region. In transfection assays using fibroblast cells, the fgf4 gene was upregulated in the presence of both MAZR and Bach2 in a BTB/POZ domain-dependent manner. The results provide a new perspective on the function of BTB/POZ domain factors and indicate that BTB/POZ domain-mediated oligomers of transcription factors may serve as combinatorial codes for gene expression.

Amino Acid Sequence↗

PubMed2000

Upregulation of two death pathways of perforin/granzyme and FasL/Fas in septic acute respiratory distress syndrome.

Accumulation and activation of inflammatory cells in the lung characterize the acute respiratory distress syndrome (ARDS). However, the precise mechanism for lung epithelial and endothelial cell damage remains unknown. Based on evidence that rapid apoptosis caused by CD8(+) cytolytic T cells can induce pathological cell death, we hypothesized that this mechanism may also participate in the acute lung injury, and attempted to evaluate apoptosis-related factors in bronchoalveolar lavage fluid (BALF) from ARDS patients. Quantitative polymerase chain reaction (PCR) analysis revealed that the messenger ribonucleic acids (mRNAs) for several apoptosis molecules, such as perforin, granzyme A, granzyme B, FasL, and Fas were highly upregulated in the acute phase of ARDS following sepsis. In contrast, low or negligible mRNA expression of these molecules was detected in patients with normal lung function, in septic patients without lung injury (septic non-ARDS), and in patients in the late phase of septic ARDS (late ARDS). While the genes of the classic proinflammatory cytokines interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), IL-6, and IL-8, and inducible nitric oxide synthase (iNOS) were upregulated in septic non-ARDS or late ARDS patients, expressions of these genes in the acute phase of septic ARDS were most distinct. The immunofluorescence flow cytometry showed that only the lymphocyte population in BALF from acute phase of septic ARDS patients expressed perforin and granzyme. The level of soluble FasL in the BALF increased only in the acute ARDS patients. These results thus suggested that the dual apoptosis pathway, perforin/granzyme and FasL/Fas system, is likely to be another participant for the pathogenesis of acute lung injury.

Adult↗

PubMed2000

Prediction of bone mass change after parathyroidectomy in patients with primary hyperparathyroidism.

A major challenge in the management of primary hyperparathyroidism (pHPT) is the decision regarding which patients should undergo parathyroidectomy (PTX), although the Consensus Development Conference of the NIH has proposed guidelines for the indication of surgery. In the present study, changes in bone mineral density (BMD) after PTX were compared between pHPT patients who did and did not meet the NIH criteria, and we further tried to predict the BMD change after PTX from preoperative parameters. The subjects were 44 pHPT patients (30 women and 14 men) who had had successful PTX. Lumbar and radial BMD were measured before and 1 yr after PTX by dual energy x-ray absorptiometry and single photon absorptiometry, respectively. Average annual percent increases in lumbar and radial BMD after PTX were 12.2 +/- 1.4% and 11.6 +/- 1.6% (mean +/- SEM), respectively, and those net increases were 0.0803 +/- 0.0008 and 0.0484 +/- 0.0006 g/cm2, respectively. There were no significant differences in percent or net changes in either radial or lumbar BMD after PTX between the groups divided according to each of the NIH criteria, such as age (> or =50 and <50 yr), serum calcium level (> or =12 and <12 mg/dL) or the existence of urinary stones (presence and absence). On the other hand, when the subjects were divided on the basis of radial BMD (above and below a z-score of -2), the annual percent and net increases in lumbar BMD and percent increase in radial BMD after PTX were significantly higher in the group with the lower z-score. Next, patients were divided into two groups with and without the indication of PTX based on NIH guidelines. Twenty-nine patients had the surgical indication by meeting one or more of these criteria and 15 patients had no indication without meeting any of the criteria. There were no significant differences between the two groups in annual percent or net changes in radial or lumbar BMD after PTX. A stepwise multiple regression analysis revealed that serum alkaline phosphatase level and the severity of cortical bone mass reduction were the best predictors of both percentage and net changes in lumbar BMD, with high determination coefficients (r2 > 0.7). In conclusion, a considerable increase in BMD could be obtained after PTX even in patients without surgical indication from the NIH. Alkaline phosphatase and the severity of cortical bone mass reduction are clinically useful for predicting the changes in lumbar BMD after PTX. The present findings provide a useful clue for the indication of surgery in pHPT.

Alkaline Phosphatase↗

PubMed2000

An artificial plastic receptor that discriminates axial asymmetry.

An artificial plastic receptor that can discriminate axial asymmetry of optically active binaphthyldiamine derivatives was prepared by the 'molecular imprinting' technique. A light-radical polymerization in the presence of an axially asymmetric compound, (R)-2,2'-bis-methylcarbonylamino-1,1'-binaphthyl (binaphthyldiamine bis-acetamide (BINADA-ac)) as a template molecule with methacrylic acid (MA) as a functional monomer, and ethyleneglycol dimethacrylate (EGDMA) as a crosslinker, at 4 degrees C. The obtained polymer exhibited a superior enantioselectivity to the (R)-enantiomer by HPLC analyses. This plastic receptor should recognize the template molecule with its shape and character of its functional groups. It should be useful in the development of chiral stationary phases for the optical resolutions of axially asymmetric compounds.

Journal Article↗

PubMed2000

Formate dehydrogenase gene of Arabidopsis thaliana is induced by formaldehyde and not by formic acid.

Variability of expression of formate dehydrogenase (FDH) caused by uptake of C-1 compounds was examined by using Arabidopsis thaliana as a model plant. Effects of uptake of several C-1 compounds were evaluated by Northern blot analysis using cDNA of A. thaliana FDH prepared by cloning on the basis of known sequence. As a result, expression of the FDH gene in A. thaliana was not intensely influenced by formic acid, an inherent substrate for FDH, but strongly induced by its reduced form, formaldehyde.

Journal Article↗

PubMed2000

A histochemical study of the camel (Camelus bactrianus) duodenal glands.

The complex carbohydrates in the camel duodenal glands were examined histochemically at light and electron microscopic levels. The duodenal glands of the camel were distributed in the submucosa 2 m caudal from the pylorus. These were branched tubuloalveolar glands. The terminal portion of each lobule was formed by only one type of mucous cell. The duodenal gland cells contained acidic and neutral carbohydrates. The mucous cells mainly contained sulfate and carboxyl carbohydrate with sialic acid, and they also contained a few neutral carbohydrates with different saccharide residues such as mannose, glucose, galactose, N-acetyl glucosamine and N-acetyl galactosamine. The results showed that the secretary granules of the duodenal glands in the camel contain mainly acidic carbohydrates. These findings seem to be the morphological characteristics of the duodenal glands in the camel.

Animals↗

PubMed2000

Tibiofemoral movement 3: full flexion in the living knee studied by MRI.

We studied active flexion from 90 degrees to 133 degrees and passive flexion to 162 degrees using MRI in 20 unloaded knees in Japanese subjects. Flexion over this arc is accompanied by backward movement of the medial femoral condyle of 4.0 mm and by backward movement laterally of 15 mm, i.e., by internal rotation of the tibia. At 162 degrees the lateral femoral condyle lies posterior to the tibia.

Adult↗

PubMed2000

Evaluation of changes in bone density and biochemical parameters after parathyroidectomy in primary hyperparathyroidism.

We examined the relationships between serum levels of intact parathyroid hormone (PTH) and alkaline phosphatase (ALP) versus bone mineral density (BMD) at the lumbar spine and radius in terms of their preoperative values and of their annual percentage and net changes after parathyroidectomy (PTX) in 44 Japanese patients (14 men and 30 women) with primary hyperparathyroidism (pHPT). Lumbar and radial BMD values were measured by dual energy X-ray absorptiometry and single photon absorptiometry and were used for evaluating the cancellous and cortical bone mass, respectively. Age- and sex-adjusted value (Z-score) of the radial BMD was significantly lower than that of the lumbar BMD before and after PTX (P < 0.05). In preoperative patients, serum levels of both intact PTH and ALP were significantly and negatively correlated with Z-score of the radial BMD (P < 0.05 and P < 0.001, respectively), but not with that of the lumbar BMD. After PTX, serum levels of calcium, phosphorus, ALP, and PTH became normal, and both lumbar and radial BMD values markedly increased over 1 year, with percentage changes of 12.2+/-1.4% and 11.6+/-1.6%, respectively, which were larger than those in any other Caucasian study previously documented. Even in patients without osteopenia (Z-score of BMD 20), lumbar and radial BMD values increased considerably after the operation (9.6+/-1.9% and 6.7+/-1.4%, respectively). Annual percentage and net changes in lumbar BMD were significantly and negatively correlated with those in ALP with high correlation coefficients, but those in radial BMD were correlated only with the annual net change in ALP but not with the percentage change. No significant correlations were observed between annual changes in either lumbar or radial BMD and those in intact PTH. Taken together, this study shows that PTX causes dramatic improvements in both the cancellous and cortical bone mass in Japanese pHPT patients regardless of the severity of their osteopenia, and suggests that the cancellous and cortical bones react differently to a preoperative endogenous PTH excess and a high bone turnover rate as well as to the postoperative normalization of a bone turnover rate in the patients.

Alkaline Phosphatase↗

PubMed2000

Gravimorphogenesis of Cucurbitaceae plants: development of peg cells and graviperception mechanism in cucumber seedlings.

We examined the effect of microgravity on the peg formation of cucumber seedlings for clarifying the mechanism of gravimorphogenesis in cucurbitaceous plants. The spaceflight experiments verified that gravity controls the formation of peg, hypocotyl hook and growth orientation of cucumber seedlings. Space-grown cucumber developed a peg on each side of the transition zone of the hypocotyl and root, indicating that on the ground peg formation is regulated negatively by gravity (Takahashi et al. 2000). It was found that the auxin-regulated gene, CS-IAA1, was strongly expressed in the transition zone where peg develops (Fujii et al. 2000). In the seedlings grown horizontally on the ground, CS-IAA1 transcripts were much abundant on the lower side of the transition zone, but no such differential expression of CS-IAA1 was observed in the space-grown cucumber (Kamada et al. 2000). These results imply that gravity plays a role in peg formation through auxin redistribution. By the negative control, peg formation on the upper side of the transition zone in the horizontally growing seedlings might be suppressed due to a reduction in auxin concentration. The threshold theory of auxin concentration accounted for the new concept, negative control of morphogenesis by gravity (Kamada et al. 2000). Anatomical studies have shown that there exists the target cells destined to be a peg and distinguishable at the early stage of the growth. Ultra-structural analysis suggested that endoplasmic reticulum develops well in the cells of the future peg. Furthermore, it was found that reorganization of cortical microtubules is required for the change in cell growth polarity in the process of peg formation. The spaceflight experiment with cucumber seedlings also suggested that in microgravity positive hydrotropic response of roots occurred without interference by gravitropic response (Takahashi et al. 1999b). Thus, this spaceflight experiment together with the ground-based studies has shown that cucumber seedling is an ideal for the study of gravimorphogenesis, hydrotropism and their interaction. Although peg formation is seen specifically in cucurbitaceous seedlings, it involves graviperception, auxin transport and redistribution and cytoskeletal modification for controlling cell growth polarity. This system could be a useful model for studying important current issues in plant biology.

Cucumis sativus↗