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Biomedical subjects

R Kobayashi

Publications and source records attributed to R Kobayashi.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Five cases of lung cancer with emphysematous bullae].

In bullous lung disease the incidence of lung cancer occurs with significant frequency among the general population, but lung cancer with a spontaneous pneumothorax is rare, and the prognosis is frequently poor. Five cases of lung cancer with emphysematous bullae of the lung were reported. In 4 cases there were simultaneous occurrences of lung cancer and pneumothorax. The patients were 49-, 36- and 68-year-old men and a 72-year-old woman, and the initial sign in all was pneumothorax. Histologically, there was one squamous cell carcinoma, two poorly differentiated adenocarcinomas and one well-differentiated adenocarcinoma. In the other case, giant emphysematous bullae were diagnosed in a 51-year-old man and were treated by bullectomy. Histological examination incidentally revealed a small well-differentiated adenocarcinoma, which extended along the wall of the largest right bulla. About 18 months later, the patient was found to have poorly differentiated adenocarcinoma of the left lung, which was treated surgically. We should always be careful of lung cancer associated with emphysematous bullae and pneumothorax.

Adenocarcinoma↗
PubMed2000

Substrate recognition by the collagen-binding domain of Clostridium histolyticum class I collagenase.

Clostridium histolyticum type I collagenase (ColG) has a segmental structure, S1+S2+S3a+S3b. S3a and S3b bound to insoluble collagen, but S2 did not, thus indicating that S3 forms a collagen-binding domain (CBD). Because S3a+S3b showed the most efficient binding to substrate, cooperative binding by both domains was suggested for the enzyme. Monomeric (S3b) and tandem (S3a+S3b) CBDs bound to atelocollagen, which contains only the collagenous region. However, they did not bind to telopeptides immobilized on Sepharose beads. These results suggested that the binding site(s) for the CBD is(are) present in the collagenous region. The CBD bound to immobilized collagenous peptides, (Pro-Hyp-Gly)(n) and (Pro-Pro-Gly)(n), only when n is large enough to allow the peptides to have a triple-helical conformation. They did not bind to various peptides with similar amino acid sequences or to gelatin, which lacks a triple-helical conformation. The CBD did not bind to immobilized Glc-Gal disaccharide, which is attached to the side chains of hydroxylysine residues in the collagenous region. These observations suggested that the CBD specifically recognizes the triple-helical conformation made by three polypeptide chains in the collagenous region.

Base Sequence↗
PubMed2000

A basal transcription factor that activates or represses transcription.

We have identified an activity that is required for transcription of downstream promoter element (DPE)-containing core promoters in vitro. The purified factor was found to be the Drosophila homolog of the transcriptional repressor known as NC2 or Dr1-Drap1. Purified recombinant dNC2 activates DPE-driven promoters and represses TATA-driven promoters. A mutant version of dNC2 can activate DPE promoters but is unable to repress TATA promoters. Thus, the activation and repression functions are distinct. These studies reveal that NC2 (Dr1-Drap1) is a bifunctional basal transcription factor that differentially regulates gene transcription through DPE or TATA box motifs.

Animals↗
PubMed2000

Enhanced expression and activation of Ca(2+)/calmodulin-dependent protein kinase IV in hepatocellular carcinoma.

BACKGROUND: Ca(2+)/calmodulin-dependent protein kinase IV (CaM-kinase IV) is a multifunctional protein kinase that is expressed abundantly in the central nervous system and, to a lesser degree, in nonneuronal tissues such as the liver. In the current study, the authors demonstrated the expression of CaM-kinase IV in hepatocytes from hepatocellular carcinoma (HCC) in both humans and rats. METHODS: Immunoblotting and immunohistochemical analysis were performed to confirm the expression of CaM-kinase IV and CaM-kinase kinase in HCC occurring in both humans and rats. The kinase activity of CaM-kinase IV in the lysate of each of these liver supernatant fluids was measured using a specific substrate (peptide gamma) for this enzyme before and after phosphorylation by exogenously added CaM-kinase kinase. RESULTS: Marked positive staining of HCC hepatocytes was found and the subcellular staining pattern mainly was cytosolic. One immunoreactive band with a molecular weight of 64 kilodaltons, which was identical to an isoform of rat cerebellum CaM-kinase IV, was demonstrated by immunoblotting. Ca(2+)/calmodulin-dependent CaM-kinase IV activity was high in HCC and showed almost no difference in activity in specimens with and without CaM-kinase kinase phosphorylation. CONCLUSIONS: CaM-kinase IV was found to be expressed in HCC and might have been involved in the development of HCC. CaM-kinase IV that was expressed in cancerous hepatocytes was phosphorylated mainly by CaM-kinase kinase that also was expressed in tumor cells.

Animals↗
PubMed2000

Evaluation of ABO and Lewis genotypes using primer extension preamplification.

There are some difficulties with blood typing from ABO variant bloodstains and Lewis negative samples using serologic methods. In these samples, DNA analysis should be employed simultaneously to avoid errors in typing. Primer extension preamplification (PEP) produces copies of template DNA. The minimum quantity to examine nucleotide substitutions of ABO and Lewis genotypes by PCR ranged from 1 to 3 ng DNA. The PCR products with or without PEP treatment showed identical ABO and Lewis genotyping results. Performing both serologic and PCR testing served to crosscheck the ABO and Lewis grouping of such specimens. Errors in ABO and Lewis typing can be avoided as discrepancies are investigated further. The application of the PEP method to limited amounts of DNA samples for ABO and Lewis blood groupings is useful.

ABO Blood-Group System↗
PubMed2000

Expression and subcellular localization of multifunctional calmodulin-dependent protein kinases-I, -II and -IV are altered in rat hippocampal CA1 neurons after induction of long-term potentiation.

Long-term potentiation (LTP) is considered to be associated with an increase in expression as well as activity of Ca(2+)/calmodulin-dependent protein kinases (CaMKs). LTP-induced and control hippocampal slices were studied by immunohistochemical and electronmicroscopic analyses using anti-CaMK-I, -II and -IV antibodies. All three kinases were demonstrated to increase their expression in CA1 neurons. CaMK-I was shown to mainly localize in the cytoplasm of the control and LTP-induced neurons, and a significant increase of immunoreactivity was observed in the latter neurons. A part of CaMK-I was found to translocate to the nuclei of LTP-induced hippocampal CA1 neurons. Direct evidence of the translocation of CaMK-II from cytoplasm to nuclei in LTP was demonstrated by immuno-electronmicroscopy. A significant increase in expression of CaMK-IV in the nuclei was also observed. Our data suggest that all the three CaMKs were actively involved in nuclear Ca(2+)-signaling in LTP.

Animals↗
PubMed2000

Identification and characterization of SA/Scc3p subunits in the Xenopus and human cohesin complexes.

A multisubunit protein complex, termed cohesin, plays an essential role in sister chromatid cohesion in yeast and in Xenopus laevis cell-free extracts. We report here that two distinct cohesin complexes exist in Xenopus egg extracts. A 14S complex (x-cohesin(SA1)) contains XSMC1, XSMC3, XRAD21, and a newly identified subunit, XSA1. In a second 12.5S complex (x-cohesin(SA2)), XSMC1, XSMC3, and XRAD21 associate with a different subunit, XSA2. Both XSA1 and XSA2 belong to the SA family of mammalian proteins and exhibit similarity to Scc3p, a recently identified component of yeast cohesin. In Xenopus egg extracts, x-cohesin(SA1) is predominant, whereas x-cohesin(SA2) constitutes only a very minor population. Human cells have a similar pair of cohesin complexes, but the SA2-type is the dominant form in somatic tissue culture cells. Immunolocalization experiments suggest that chromatin association of cohesin(SA1) and cohesin(SA2) may be differentially regulated. Dissociation of x-cohesin(SA1) from chromatin correlates with phosphorylation of XSA1 in the cell-free extracts. Purified cdc2-cyclin B can phosphorylate XSA1 in vitro and reduce the ability of x-cohesin(SA1) to bind to DNA or chromatin. These results shed light on the mechanism by which sister chromatid cohesion is partially dissolved in early mitosis, far before the onset of anaphase, in vertebrate cells.

Amino Acid Sequence↗
PubMed2000

Regulatory mechanism of Ca2+/calmodulin-dependent protein kinase kinase.

Ca(2+)/calmodulin-dependent protein kinase kinase (CaM-KK) is a novel member of the CaM kinase family, which specifically phosphorylates and activates CaM kinase I and IV. In this study, we characterized the CaM-binding peptide of alphaCaM-KK (residues 438-463), which suppressed the activity of constitutively active CaM-KK (84-434) in the absence of Ca(2+)/CaM but competitively with ATP. Truncation and site-directed mutagenesis of the CaM-binding region in CaM-KK reveal that Ile(441) is essential for autoinhibition of CaM-KK. Furthermore, CaM-KK chimera mutants containing the CaM-binding sequence of either myosin light chain kinases or CaM kinase II located C-terminal of Leu(440), exhibited enhanced Ca(2+)/CaM-independent activity (60% of total activity). Although the CaM-binding domains of myosin light chain kinases and CaM kinase II bind to the N- and C-terminal domains of CaM in the opposite orientation to CaM-KK (Osawa, M., Tokumitsu, H., Swindells, M. B., Kurihara, H., Orita, M., Shibanuma, T., Furuya, T., and Ikura, M. (1999) Nat. Struct. Biol. 6, 819-824), the chimeric CaM-KKs containing Ile(441) remained Ca(2+)/CaM-dependent. This result demonstrates that the orientation of the CaM binding is not critical for relief of CaM-KK autoinhibition. However, the requirement of Ile(441) for autoinhibition, which is located at the -3 position from the N-terminal anchoring residue (Trp(444)) to CaM, accounts for the opposite orientation of CaM binding of CaM-KK compared with other CaM kinases.

Amino Acid Sequence↗
PubMed2000

Identification of tranilast-binding protein as 36-kDa microfibril-associated glycoprotein by drug affinity chromatography, and its localization in human skin.

To elucidate the molecular mechanism involved in the suppression of keloids and hypertrophic scars by tranilast, we investigated the target protein of tranilast in bovine skin and aorta. A specific tranilast-binding protein was isolated from both tissues by drug affinity chromatography and was identified as 36-kDa microfibril-associated glycoprotein (36-kDa MAGP). Binding of 36-kDa MAGP to tranilast seemed to be specific since 36-kDa MAGP could be eluted from the drug affinity column by tranilast itself and also binding of 36-kDa MAGP to other anti-allergy drugs (amlexanox and cromolyn) is significantly weaker than that to tranilast. Light and electron microscopic immunohistochemistry detected the protein at the periphery of elastic fibers in normal human skin. In hypertrophic scar tissue, however, 36-kDa MAGP was located on small bundles of microfibrils. These findings provide support for the concept that elastogenesis occurs in scar tissue and 36-kDa MAGP might be one of the targets for tranilast.

Amino Acid Sequence↗
PubMed2000

Experimental hyperthyroidism causes inactivation of the branched-chain alpha-ketoacid dehydrogenase complex in rat liver.

Hyperthyroidism induced by 3-day treatment of rats with thyroid hormone (T(3); 3,5,3'-triiodothyronine) at 0.1 or 1 mg/kg body wt/day resulted in a reduced activity state (% of enzyme in its active, dephosphorylated state) of the hepatic branched-chain alpha-ketoacid dehydrogenase (BCKDH) complex. One treatment with 0.1 mg T(3)/kg body wt caused a significant effect on the activity state of BCKDH complex after 24 h, indicating that the reduction of the activity state was triggered by the first administration of T(3). Hyperthyroidism also caused a stable increase in BCKDH kinase activity, the enzyme responsible for phosphorylation and inactivation of the BCKDH complex, suggesting that T(3) caused inactivation of the BCKDH complex by induction of its kinase. Western blot analysis also revealed increased amounts of BCKDH kinase protein in response to hyperthyroidism. No change in the plasma levels of branched-chain alpha-keto acids was observed in T(3)-treated rats, arguing against an involvement of these known regulators of BCKDH kinase activity. Inactivation of the hepatic BCKDH complex as a consequence of overexpression of its kinase may save the essential branched-chain amino acids for protein synthesis during hyperthyroidism.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed2000

Tyrosine phosphorylation of p62dok by p210bcr-abl inhibits RasGAP activity.

The t(9;22) chromosomal translocation is found in almost all patients with chronic myelogenous leukemia. The resultant Bcr-Abl fusion gene expresses a chimeric fusion protein p210(bcr-abl) with increased tyrosine kinase activity. Hematopoietic progenitors isolated from chronic myelogenous leukemia patients in the chronic phase contain constitutively tyrosine-phosphorylated p62(dok) protein. p62(dok) associates with the Ras GTPase-activating protein (RasGAP), but only when p62(dok) is tyrosine phosphorylated. Here we have investigated the interaction between p62(dok) and RasGAP and the consequences of p62(dok) tyrosine phosphorylation on the activity of RasGAP. We have found that p62(dok) is directly tyrosine phosphorylated by p210(bcr-abl), and the sites of phosphorylation are located in the C-terminal half of the p62(dok) molecule. We have identified five tyrosine residues that are involved in in vitro RasGAP binding and have found that tyrosine-phosphorylated p62(dok) inhibits RasGAP activity. Our results suggest that p210(bcr-abl) might lead to the activation of the Ras signaling pathway by inhibiting a key down-regulator of Ras signaling.

Amino Acid Sequence↗
PubMed2000

Expression of elastin-related proteins and matrix metalloproteinases in actinic elastosis of sun-damaged skin.

Actinic elastosis is characterized by an accumulation of elastotic material in the upper dermis and is considered to be a manifestation of ultraviolet-induced skin aging. To compare the structural components of the elastotic material in actinic elastosis with those in normal skin, skin specimens were stained with antibodies raised against various elastin-related proteins. Elastotic materials exhibited a strong reaction to the antibodies for elastin, microfibril-associated glycoprotein-1 (MAGP-1), MAGP-4, matrix metalloproteinase 1 (MMP-1), MMP-2 and MMP-3, but a diminished reaction to anti-MMP-9 antibody. Fibroblast cell lines from the upper dermis of affected and unaffected skin were established, and the mRNA levels of MMPs were determined. MMP-1 and -2 mRNA levels were found to be elevated approximately twofold in the fibroblasts from actinic elastosis. Since MMP-1 and -2 are considered to be major enzymes involved in the degradation of matrix components, the accumulation of elastotic materials in actinic elastosis may be related to the degradation process.

Aged↗
PubMed2000

High-resolution CT findings of macrophage activation syndrome: a case report.

Macrophage activation syndrome (MAS) is a rare disorder characterised by benign, reactive, excessive, well-differentiated macrophage proliferation, secondary to an immune dysregulation in response to some triggering agents such as viral infection. We report a 3-year-old girl with MAS and pulmonary involvement. This is the first radiographic description of MAS on high-resolution CT.

Anti-Inflammatory Agents↗
PubMed2000

Clinical factors associated with post-ictal headache in patients with epilepsy.

OBJECTIVES: To determine the incidence of post-ictal headaches (PIH) and clinical risk factors associated with the occurrence of PIH in patients with localization-related epilepsy. MATERIALS AND METHODS: The subjects were 77 patients with temporal lobe epilepsy (TLE), 34 patients with occipital lobe epilepsy (OLE), and 50 patients with frontal lobe epilepsy (FLE). The subjects were directly asked whether headaches occurred just after seizures. Medical charts were reviewed to ascertain the clinical characteristics of epilepsy in these patients. RESULTS: The incidence of PIH was 23% for TLE, 62% for OLE, and 42%, for FLE. The risk of PIH was significantly higher for OLE than for TLE or FLE, and for patients with generalized tonic-clonic seizures. Younger age at onset of epilepsy was also a risk factor for PIH. CONCLUSION: The occurrence of PIH may be related to the region of epileptic focus and the region of spread of epileptic discharges.

Adolescent↗
PubMed2000

Three-dimensional measurement of rolling in tetraplegic patients.

OBJECTIVE: To investigate the differences between traumatic tetraplegic patients who can roll and those who cannot. DESIGN: Motion analysis using 3-dimensional measurement. SETTING: Rehabilitation centers in southwestern Japan. PARTICIPANTS: Nineteen male participants, all of whom had traumatic C6 complete injury. METHODS: We used an electromagnetic device to examine the degree of spinal movement in axial rotation during rolling (shifting from supine to side lying). This system (3-Space Win) measures the position and orientation of sensors in space. Two sensors were mounted on a subject over the spinous process of T1 and L5. RESULTS: The spinal rotation of patients who could not roll was significantly lower than that of patients who could roll. (The average rotation of non-rollers was 31.5+/-17.5 degrees, while the average rotation of rollers was 66.3+/-17.3degrees). In this study, there were no statistically significant differences in the members of the two groups in terms of age, height, weight or time after injury. CONCLUSION: Rolling requires greater and adequate flexibility in the back of tetraplegic patients.

Adult↗
PubMed2000

Affective communication of infants with autistic spectrum disorder and internal representation of their mothers.

We have been examining the developmental process of affective communication in infants with autistic spectrum disorders from the viewpoint of relationship disturbance through our developmental and psychopathological studies on autism. In particular, the role of internal representation of the mother in the process of development of affective communication is discussed through the presentation of two cases diagnosed as autistic spectrum disorder in early infancy. In these cases, we postulate approach-avoidance motivational conflict as the primary factor impeding development of affective communication, focusing therapeutic intervention on this perspective. As a result, attachment behavior was remarkably improved in the children, but affective communication with their mothers was not readily improved. Taking up the mothers' own internal representation in mother-infant psychotherapy, in particular, the mothers' problems in attachment behavior with their own mothers in infancy precipitated transition in the mothers' internal representation of their children, leading to active evolution in mother-child interaction and development in affective communication between mother and child. In this context, the basis and significance of internal representation of both parties being determinants in the quality of mother-child communication are discussed.

Affect↗