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Biomedical subjects

K Tamai

Publications and source records attributed to K Tamai.

At least 145 records · Page 8Linked to original sources
PubMed1995

A quantitative color recognition measurement system using multimedia computer environment.

We developed a quantitative measurement system that tests the degree of dysgnosia resulting from Obsessive-Compulsive Disorder (OCD). The system outputs a stimulation word that had been set in advance using the voice output facility of the personal computer, then displays a color chart and waits for input from the subject. When the subject touches the CRT screen or clicks the mouse, the system records the response time and coordinates of input position. There were 30 stimulation words in the system. After 30 measurements of response time and input coordinates, the system outputs a results file that includes each response time and input coordinates. This test is easier and simpler than other psychological tests such as MMPI. The influence of the examiner can be reduced to the minimum with this system because it is a computer-based automatic measurement system. To use the computer system, an examiner can easily standardize the environment of the illumination, etc. Moreover, the system can save labor in testing, and can manage large amounts of data easily using the file management facility.

Association↗
PubMed1995

Expression patterns of DNA replication enzymes and the regulatory factor DREF during Drosophila development analyzed with specific antibodies.

Specific antibodies were prepared against Drosophila DNA polymerase epsilon and DREF, a regulatory factor for DNA replication-related genes. Using these antibodies together with those for DNA polymerase alpha and proliferating cell nuclear antigen (PCNA), we examined expression patterns and sub-cellular distributions of these proteins during Drosophila development. DNA polymerase alpha, epsilon and PCNA proteins were maternally stored in unfertilized eggs and maintained at high levels during embryogenesis. With distinct nuclear localization, proteins were observed in embryos at interphase stages throughout the 13 nuclear division cycles, suggesting that they all participate in rapid nuclear DNA replication during these cycles. In contrast, maternal storage of a DREF protein was relatively low and its level increased throughout embryogenesis. Strong nuclear staining with the anti-DREF antibody was not observed until the nuclear division cycle 8. Immunostaining of various larval tissues from transgenic flies carrying the PCNA gene promoter-lacZ fusion gene revealed co-expression of DREF, PCNA and lacZ, suggesting that DREF regulates the expression of PCNA gene in these tissues. In addition, we detected a relatively high level of DREF in adult males as well as females. Since DNA polymerase alpha, epsilon and PCNA are hardly detectable in adult males, DREF very likely regulates genes other than those closely linked to DNA replication in adult males.

Animals↗
PubMed1995

Distribution of protein kinase C (alpha, beta, gamma subtypes) in normal nerve fibers and in regenerating growth cones of the rat peripheral nervous system.

The distribution of protein kinase C (alpha, beta, gamma subtypes) was studied using immunocytochemical techniques in normal nerve fibers and in regenerating sprouts (growth cones) from the nodes of Ranvier following crush injuries to the rat peripheral nervous system. In normal nerves, for each protein kinase C subtype, immunoreactivity was present in both myelinated and unmyelinated axons. In myelinated axons, immunoreactivity for all three subtypes was patchy in the axoplasm and diffuse in the subaxolemmal peripheral zones. No immunoreactivity was found in the microtubule and neurofilament (cytoskeletal) domain. In contrast, in unmyelinated axons, immunoreactivity was distributed diffusely in the axoplasm. Schwann cells of myelinated fibers exhibited protein kinase C immunoreactivity, but those of unmyelinated fibers did not. In regenerating nerves, early sprouts and growth cones extending through the crushed site along Schwann cell basal laminae exhibited intense immunoreactivity for all three subtypes. Immunoreactivity was distributed diffusely throughout the axoplasm of the regenerating sprouts (growth cones), in which microtubules and neurofilaments were very rare. Thus, the subcellular localization of the protein kinase C immunoreactivity in growth cones of early regenerating nerves differed from that of normal parent axons. These findings suggest that protein kinase C (alpha, beta and gamma subtypes), whose subcellular distribution becomes more extensive in regenerating axons, may have important functional roles in axonal sprouting and in the regulation of growth cone activity in the peripheral nervous system.

Animals↗
PubMed1995

Characterization of myotonic dystrophy kinase (DMK) protein in human and rodent muscle and central nervous tissue.

Myotonic dystrophy (DM) is the most common form of inherited neuromuscular disease in adults and is characterized by progressive muscle wasting and myotonia. The mutation responsible for DM has been identified as the amplification of a polymorphic (CTG)n repeat in the 3' untranslated region of a gene encoding a serine/threonine kinase (DMK). We have produced a polyclonal rabbit antibody preparation against a fusion protein encoding the C-terminal amino acids 471-629 of the human DMK gene. This antibody specifically detects products of both full length and truncated human DMK genes expressed in bacteria and in insect cells. On immunoblots, we observed protein species of approximately 74 and 82 kDa in cardiac muscle, skeletal muscle, ependyma and choroid plexus. By immunofluorescence, DMK was found to localize post-synaptically at the neuromuscular junction of skeletal muscle, at intercalated discs of cardiac tissue and at the apical membrane of the ependyma and choroid plexus. We have also detected two to three species (approximately 45-50 kDa) in other regions of the brain. Synaptic localization of DMK in the cerebellum, hippocampus, midbrain and medulla was noted. These results suggest that DMK plays a specialized role in intercellular communication.

Aged↗
PubMed1995

Interferon-gamma coordinately upregulates matrix metalloprotease (MMP)-1 and MMP-3, but not tissue inhibitor of metalloproteases (TIMP), expression in cultured keratinocytes.

Matrix metalloproteases (MMP) constitute a family of proteolytic enzymes degrading extracellular matrix components. Their activity is inhibited by tissue inhibitors of metalloproteases (TIMP). Previous studies have demonstrated that various cytokines can modulate MMP and TIMP gene expression. In this study, we demonstrate that interferon-gamma coordinately upregulates MMP-1 (interstitial collagenase) and MMP-3 (stromelysin-1) gene expression in cultured keratinocytes, as determined at the mRNA steady-state levels, and this effect is dependent on on-going protein synthesis. In contrast, there was no effect on TIMP-1 gene expression. Enhanced MMP-1 expression by IFN-gamma was also demonstrated at the protein level by Western analysis. Transient transfections with MMP-1 and MMP-3 promoter/reporter gene constructs revealed no response to IFN-gamma, whereas incubation of keratinocytes with this cytokine appeared to stabilize the MMP-1 mRNA, resulting in reduced turnover of the transcript. These data suggest that IFN-gamma enhances MMP gene expression at the post-transcriptional level. The altered MMP expression by IFN-gamma without concomitant effect on TIMP gene expression potentially leads to imbalance between these proteases and their inhibitors, and enhanced proteolytic activity may play a role in the remodeling of cutaneous tissue involving inflammatory processes, such as wound healing.

Adult↗
PubMed1995

A study of the steroid sulfatase gene in families with X-linked ichthyosis using polymerase chain reaction.

We have studied the steroid sulfatase (STS) gene in three Japanese families with X-linked ichthyosis (XLI), using polymerase chain reaction (PCR). PCR was performed using three sets of intraexonic primers covering exons 1, 5 and 10. In affected individuals from two of the families, DNA was not amplified in any of the three exons, suggesting that XLI in these families was due to the complete deletion of the STS gene. In affected individuals in the remaining family, DNA was amplified in predicted sizes in exons 1 and 5, but not in exon 10, suggesting that XLI in this family was due to partial deletion of the STS gene including exon 10. These results suggested that STS gene deficiency is heterogeneous in Japanese families with XLI. PCR is useful for the rapid diagnosis of XLI, the differentiation of XLI from ichthyosis vulgaris, and genetic counseling of XLI families. The PCR method was not applicable for carrier detection.

Adolescent↗
PubMed1995

Effects of local hypothermia on uveal blood flow and postoperative inflammation in vitrectomy.

Effects of local hypothermia on uveal blood flow and postoperative inflammation were evaluated in experimental vitrectomy in albino rabbits. Solutions used for intraocular perfusion were maintained at 9 degrees C, 22 degrees C or 37 degrees C. Following closed vitrectomy, the vitreous cavity was irrigated for 60 minutes. Temperatures at various sites and uveal blood flow were measured before and during the procedure. Aqueous protein concentrations were checked on postoperative days 1, 7 and 14. There was a larger decrease in temperature at the retina than at the choroid or the ciliary body. Blood flow at the ciliary body was reduced to 76.0% and that at the choroid to 77.0% of the preoperative level after 60 minutes of irrigation at 9 degrees C. The decrease was 91.0% and 88.3%, respectively, after 60 minutes of irrigation at 22 degrees C. Aqueous protein concentrations in the 9 degrees C and 22 degrees C groups were significantly lower than those in the 37 degrees C group on the first postoperative day in the eyes irrigated for 60 minutes. In the eyes irrigated for 30 minutes, however, no significant differences were seen. Local hypothermia during prolonged vitrectomy seems to decrease inflammation in the early postoperative stage.

Animals↗
PubMed1995

Quantification of antiribosomal P0 protein antibodies by ELISA with recombinant P0 fusion protein and their association with central nervous system disease in systemic lupus erythematosus.

OBJECTIVE: Using solid phase ELISA with recombinant P0 fusion protein as the antigen for detecting antiribosomal P0 protein antibody, we analyzed the association of this antibody and anticardiolipin antibody (aCL) with central nervous system (CNS) disease in patients with active systemic lupus erythematosus (SLE). METHODS: Sera from 70 randomly selected Japanese patients with active SLE were assayed for IgG and IgM antiribosomal P0 protein antibody titers and IgG aCL. RESULTS: IgG and IgM antiribosomal P0 protein antibodies were present in 29 and 12 (41.4 and 17.1%) of the 70 patients, respectively. The incidence of CNS disease, excluding lupus psychosis, was significantly higher in patients with IgG and IgM antiribosomal P0 protein antibodies than in those who lacked them (IgG antiribosomal P0 protein antibody 11/29 vs 3/41; IgM antiribosomal P0 protein antibody 7/12 vs 7/58). In addition, both IgG and IgM antiribosomal P0 protein antibody titers were significantly higher in patients with CNS disease, excluding lupus psychosis, than those without. No significant association was observed between antiribosomal P0 protein antibodies and lupus psychosis. No significant association was observed between IgG aCL and CNS disease. Serial studies of antiribosomal P0 protein antibodies and aCL in patients with transverse myelopathy also showed that IgG and IgM antiribosomal P0 protein antibodies, but not IgG aCL, were associated with CNS disease, excluding lupus psychosis. CONCLUSION: These data suggest a strong association of IgG and IgM antiribosomal P0 protein antibodies with CNS disease, excluding lupus psychosis, in SLE.

Adolescent↗
PubMed1994

Interleukin 10 up-regulates elastin gene expression in vivo and in vitro at the transcriptional level.

In immune cells, such as T cells and monocytes, interleukin 10 (IL-10) has regulatory functions on a number of cytokines, including IL-1, IL-2, IL-8 and tumour necrosis factor-alpha expression. However, the effects of IL-10 have not previously been studied in detail in connective-tissue cells. In the present study, we show that recombinant human IL-10 at physiological concentrations has direct effects on the expression of the human elastin gene both in vivo and in vitro. Transgenic mice expressing a human elastin promoter/chloramphenicol acetyltransferase (CAT) reporter gene construct were injected subcutaneously with IL-10 (1-100 ng) and the site of injection was biopsied after 24 h. CAT assay revealed an increase of up to 3.5-fold in the promoter activity with 10 ng of IL-10. Transforming growth factor-beta 2 (TGF-beta 2) is known to up-regulate elastin gene expression in cultured fibroblasts. When IL-10 was added to such cultures, the effects of TGF-beta 2 on elastin mRNA levels were synergistically potentiated. These results suggest that IL-10 has an up-regulatory effect on elastin gene expression.

Animals↗
PubMed1994

Identification of a DNA-binding protein (keratinocyte transcriptional protein-1) recognizing a keratinocyte-specific regulatory element in the 230-kDa bullous pemphigoid antigen gene.

We have recently cloned and characterized the entire human 230-kDa bullous pemphigoid antigen gene, which is expressed at a relatively high level in the basal keratinocytes. A putative AP2 binding sequence (KRE2), identified in the position -1786 to -1778, was cloned in front of a heterologous thymidine kinase chloramphenicol acetyltransferase construct, and transient transfections of normal human keratinocytes indicated a marked enhancement of the promoter activity. Normal human keratinocyte nuclear extracts contained a protein, designated as keratinocyte transcriptional protein-1 (KTP-1), which complexed with the KRE2 oligomer when examined by gel mobility shift assays. This protein was not detected in human skin fibroblast or HeLa cell nuclear extracts that did, however, contain AP2. UV cross-linking studies and Southwestern analyses suggested that KTP-1 binds to DNA as a single polypeptide of approximately 110 kDa. These data suggest that KTP-1 is a DNA-binding protein clearly distinct from AP2, and this protein may be responsible for the basal keratinocyte-specific expression of the bullous pemphigoid antigen gene.

Adult↗
PubMed1994

Dynamic magnetic resonance imaging for the evaluation of synovitis in patients with rheumatoid arthritis.

OBJECTIVE: To investigate whether the findings of magnetic resonance imaging (MRI) reflect rheumatoid synovitis. METHODS: Dynamic imaging enhanced with gadolinium-diethylenetriamine pentaacetic acid was performed on 10 affected knees of 9 patients with rheumatoid arthritis. Changes in signal intensity were correlated with pathologic findings in synovial biopsy specimens obtained during total knee arthroplasty. RESULTS: Enhancement was greater in regions with a higher degree of fibrin exudation, cellular infiltration, villous hypertrophy, vascular proliferation, and granulation formation. CONCLUSION: Dynamic MRI can be used for assessing local disease activity in rheumatoid synovium.

Aged↗
PubMed1994

Adaptation of skeletal muscle in limb lengthening: a light diffraction study on the sarcomere length in situ.

Adaptation of skeletal muscle during limb lengthening was assessed by measurement of the length of sarcomeres in situ. An external fixator was applied to the rabbit radius and ulna to elongate the forelimb by 3.5 mm, while allowing all the joints to be free. At regular intervals after the operation, the extensor digitorum lateralis muscle of the fifth digit was exposed in situ and the length of the sarcomeres was measured by a laser diffraction technique. The sarcomeres, which had stretched to 3.51 microns immediately after elongation of the bone, became shorter with the passage of time. On postoperative day 9, the length was 3.10 microns, which was similar to the length of the unstretched muscle. These results indicated structural adaptation of the muscle to a new length and could explain why the efficiency of muscle function is maintained after limb lengthening. When these findings are combined with our previous results, it appears that stretch-induced changes in sarcomere length are common in immobilized and nonimmobilized muscles.

Adaptation, Physiological↗
PubMed1994

Substance P- and calcitonin gene-related peptide-immunofluorescent nerves in the repair of experimental bone defects.

Healing of an experimental bony defect in the rat's tibia was studied with an immunofluorescent technique to clarify when and where substance P (SP) and calcitonin gene-related peptide (CGRP) would develop. The normal tibia showed a few SP- and CGRP-immunofluorescent nerve fibres. In the experimental tibia, the number of these fibres increased on the 6th day after operation, reached a peak of proliferation on the 15th day and reverted to normal after the 24th day. The changes were associated with the development and decay of callus tissue suggesting that harmful stimuli from the injured site in a bone could be mediated by sensory nerves throughout the repair period. Most of the SP- and CGRP-immunofluorescence was seen near the vessels, frequently in the same nerve fibres. The SP- and CGRP-immunofluorescent nerves seemed to take part jointly in callus formation through the enhancement of local blood flow.

Animals↗
PubMed1994

Familial positive ulnar variance with secondary radioulnar joint arthritis and extensor tendon ruptures.

A familial pattern of extensor tendon ruptures due to distal radioulnar osteoarthritis with underlying positive ulnar variance is described. Spontaneous ruptures occurred in four members of the family (one woman and three men) in middle age. Laboratory data did not indicate any sign of rheumatoid arthritis. All cases revealed significant positive ulnar variance and distal radioulnar osteoarthritis. Younger members of the family demonstrated positive ulnar variance although without osteoarthritic changes. The tendon ruptures presumably resulted from a hereditary disorder in conjunction with degenerative changes brought about by age.

Adolescent↗
PubMed1994

Enhanced elastin and fibrillin gene expression in chronically photodamaged skin.

Cutaneous aging consists of chronologic aging as well as actinic damage, referred to as photoaging. Most of the morphologic changes associated with an aged appearance result from actinic damage to the skin. The morphologic changes in sun-damaged skin are associated with accumulation of material having the staining characteristics of elastin, known as solar elastosis, in the superficial dermis. Previous studies have demonstrated the presence of elastin within areas of solar elastosis; however, little is known about the mechanisms leading to elastin accumulation in photoaged skin. In addition, fibrillin, the fibrillar component of elastic fibers, has been found in small amounts in solar elastosis. In this study we demonstrate increased elastin mRNA levels in photoaged skin, as well as increased elastin and fibrillin mRNAs in skin explant-derived fibroblasts using Northern hybridizations, compared with controls from sun-protected sites of the same individual. Increased elastin mRNA levels result from transcriptional upregulation of the gene, as demonstrated by transient transfections with a human elastin promoter/chloramphenicol acetyltransferase construct. Elevated mRNA levels were also correlated with increased elastin and fibrillin deposition in paired biopsy specimens from photodamaged and non-sun-exposed skin, as demonstrated by immunohistochemical staining. Thus, approaches to counteract transcriptional activation of elastin gene expression may be useful in preventing the changes associated with cutaneous photoaging.

Aged↗
PubMed1994

Mouse 230-kDa bullous pemphigoid antigen gene: structural and functional characterization of the 5'-flanking region and interspecies conservation of the deduced amino-terminal peptide sequence of the protein.

The 230-kDa bullous pemphigoid antigen is a hemidesmosomal protein of the cutaneous basement membrane zone. The primary sequences deduced from full-length human cDNAs predict that this molecule consists of a central rod region and flanking globular domains. To get insight into regulation of the 230-kDa bullous pemphigoid antigen gene (BPAG1), and to evaluate evolutionary conservation of the amino-terminus of the protein, we screened a mouse genomic DNA library with a 0.3-kb cDNA corresponding to the 5' end of the human 230-kDa bullous pemphigoid antigen cDNA. A positive clone was isolated, and Southern analysis of the clone with the 0.3-kb cDNA allowed isolation of a 3.0-kb Hind III fragment containing the 5' end of the coding sequence. Alignment of the sequences of this subclone and human BPAG1 sequences revealed that this fragment contained 2466 bp of 5'-flanking DNA, upstream from the ATG translation initiation site, and 258 bp of translatable sequences that encode a putative polypeptide of 86 amino acids at the amino-terminus of the protein. This deduced polypeptide showed 91% homology with the corresponding human sequence. The TATAAA and CCAAT consensus sequences, as well as several putative cis-regulatory elements, were identified in the 5'-flanking region of the mouse DNA. To test the functional promoter activity of the 5'-flanking DNA, three mouse BPAG1 promoter/CAT reporter gene constructs, with the promoter segments spanning from -1133, -525, and -213 to -1, were developed. Transient transfections of mouse transformed keratinocytes (Pam 212 cells) with these constructs revealed clearly detectable CAT activities, indicating that the 5'-flanking region contains a functional promoter. Furthermore, these experiments suggested that the upstream sequences contain upregulatory elements, as well as elements that confer, at least in part, tissue specificity to the expression of the mouse 230-kDa BPA gene.

Amino Acid Sequence↗