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Biomedical subjects

T Kawakami

Publications and source records attributed to T Kawakami.

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

Use of vascularized pedicle iliac bone graft in the treatment of avascular necrosis of the femoral head.

A vascularized pedicle iliac bone graft was performed in patients with extensive necrosis in whom the necrotic area occupied more than two-thirds of the femoral head. The purpose of this procedure is to supply vascularity and mechanical strength to the avascular femoral head. Our series consisted of 18 hips. The patients' age at surgery ranged from 21 to 55 years. Fourteen hips were identified as stage II and 4 hips as stage III. Iliac bone graft alone was performed in 4 stage II joints. Transtrochanteric anterior rotational osteotomy of the femoral head was done additionally in 10 stage II joints and 4 stage III joints. In the group who underwent iliac bone graft alone, the mean Japanese Orthopedic Association (JOA) score improved from 58.5 to 63.8 (mean follow-up 52 months). In the group who underwent combination procedure with osteotomy, the mean JOA score improved from 71.7 to 85.0 (mean follow-up 43 months). Stage progression was noted in 3 of 4 joints in the group who underwent iliac bone graft alone. In the group who underwent the combined procedure, stage progression was noted in 2 of 10 joints at more than 1 year after operation. A vascularized pedicle iliac bone graft to treat avascular necrosis of the femoral head is considered promising for joint preservation.

Adult↗
PubMed2001

Inhibitory effect of histamine on axonal transport in cultured mouse dorsal root ganglion neurons.

Histamine is important in mediating peripheral sensory information such as inflammation, allergic hypersensitivity, and itch. In the present study, using video-enhanced microscopy, we investigated the effect of histamine on axonal transport in cultured dorsal root ganglion (DRG) neurons of the mouse. Application of histamine (100 microM) reversibly reduced the number of particles transported within neurites in both anterograde and retrograde directions. The histamine H(1)-receptor agonist 2-thiazolylethylamine (100 microM) and the H(3)-receptor agonist R-alpha-methylhistamine (100 microM) also reduced anterograde and retrograde axonal transport, whereas the histamine H(2)-receptor agonist dimaprit (100-1000 microM) had no effect. The effect of histamine was partially blocked by pretreatment with H(1)-receptor antagonist pyrilamine (1 microM) or the H(3)-receptor antagonist thioperamide (1 microM). Pretreatment with a combination of pyrilamine (1 microM) and thioperamide (1 microM) completely blocked the response to histamine. The H(2)-receptor antagonist cimetidine (1 microM) was ineffective. These results suggest that histamine inhibits axonal transport of cultured mouse DRG neurons via the activation of H(1)- and H(3)-receptors.

Animals↗
PubMed2001

Regulation of mast cell survival by IgE.

Mast cells play critical roles in hypersensitivity and in defense against certain parasites. We provide evidence that mouse mast cell survival and growth are promoted by monomeric IgE binding to its high-affinity receptor, Fc epsilon RI. Monomeric IgE does not promote DNA synthesis but suppresses the apoptosis induced by growth factor deprivation. This antiapoptotic effect occurs in parallel with IgE-induced increases in Fc epsilon RI surface expression but requires the continuous presence of IgE. This process does not involve the FasL/Fas death pathway or several Bcl-2 family proteins and induces a distinctly different signal than Fc epsilon RI cross-linking. The ability of IgE to enhance mast cell survival and Fc epsilon RI expression may contribute to amplified allergic reactions.

Animals↗
PubMed2001

Itk/Emt: a link between T cell antigen receptor-mediated Ca2+ events and cytoskeletal reorganization.

Itk/Emt, a tec family tyrosine kinase, is important for T-cell development and activation through the antigen receptor. Here, we review data suggesting that Itk/Emt is involved in the generation of critical second messengers (Ca(2+), PKC) whose duration it modulates by regulation of cytoskeletal reorganization. We propose that Itk/Emt constitutes an important link between these critical signaling events.

Animals↗
PubMed2001

Preparative-scale isolation of four anthocyanin components of black currant (Ribes nigrum L.) fruits.

Four anthocyanin components of black currant, delphinidin 3-O-beta-rutinoside (D3R), cyanidin 3-O-beta-rutinoside (C3R), delphinidin 3-O-beta-glucoside (D3G), and cyanidin 3-O-beta-glucoside (C3G), were successfully isolated as crystalline forms on a preparative scale. In this process, selective hydrolysis of the glucosides (D3G and C3G) and rhamnosides (D3R and C3R) was achieved by treatment with beta-glucosidase and hesperidinase (alpha-rhamnosidase), respectively, to improve resolution of anthocyanin components. Especially, selective conversion of the rutinosides into glucosides made the amounts of D3G and C3G increase about 4- and 7-fold, respectively. D3R, C3R, D3G, and C3G were isolated from enzymatic hydrolysates of black currant anthocyanins through Amberlite XAD-7HP absorption followed by preparative HPLC separation, and their crystals were obtained as the flavylium chloride.

Anthocyanins↗
PubMed2001

Methods for sequential resonance assignment in solid, uniformly 13C, 15N labelled peptides: quantification and application to antamanide.

The application of adiabatic polarization-transfer experiments to resonance assignment in solid, uniformly 13C-15N-labelled polypeptides is demonstrated for the cyclic decapeptide antamanide. A homonuclear correlation experiment employing the DREAM sequence for adiabatic dipolar transfer yields a complete assignment of the C(alpha) and aliphatic side-chain 13C resonances to amino acid types. The same information can be obtained from a TOBSY experiment using the recently introduced P9(12)1 TOBSY sequence, which employs the J couplings as a transfer mechanism. A comparison of the two methods is presented. Except for some aromatic phenylalanine resonances, a complete sequence-specific assignment of the 13C and 15N resonances in antamanide is achieved by a series of selective or broadband adiabatic triple-resonance experiments. Heteronuclear transfer by adiabatic-passage Hartmann-Hahn cross polarization is combined with adiabatic homonuclear transfer by the DREAM and rotational-resonance tickling sequences into two- and three-dimensional experiments. The performance of these experiments is evaluated quantitatively.

Amino Acids↗
PubMed2001

Changes in masticatory muscle activity according to food size in experimental human mastication.

The purpose of this study was to investigate the changes in masticatory muscle activity according to food size in human mastication. Sixteen subjects performed deliberate unilateral chewing of similarly cone shaped hard gummy jellies weighing 5 and 10 g. The masseter and anterior temporal muscle activity on both sides was recorded for the first 10 strokes. The normalized muscle activity during the chewing of the 10 g jelly was significantly higher than that of the 5-g jelly, and there was a considerably high significant correlationship between the muscle activity during the chewing of the 10- and 5-g jellies in each muscle on each side. The 10 g/5 g jelly ratio for the masseter muscle activity on the non-chewing side almost coincided with the theoretical energy ratio required to shear, although that of the chewing side was lower than the ratio. The 10 g/5 g jelly ratio for the temporal muscle activity on both sides almost coincided with the food height ratio. The results suggest that anterior temporal and masseter muscle activity changes according to the rate of change in the height of hard coherent food bolus and food resistance required to shear, respectively, during mastication.

Adult↗
PubMed2001

Overexpression of transforming growth factor-beta3 immunohistochemical staining in extramammary Paget's disease, but downregulated expression in Bowen's disease.

BACKGROUND: The role of transforming growth factor-beta (TGF-beta) in carcinogenesis is complex, with some reports indicating a tumor inhibition role and others indicating a tumor promotion role. In particular, TGF-beta3 is thought to play a key role in controlling epithelial homeostasis. Immunopositive p53 has been demonstrated in a variety of human malignant tumors and its role in oncogenesis and tumor progression is thought to be important. Extramammary Paget's disease (EPD) and Bowen's disease are skin cancers of unknown histogenesis. OBJECTIVE: To clarify the role of TGF-beta3 and p53 in EPD and Bowen's disease and to better understand the origin of these disorders. METHODS: Specimens were obtained from 12 patients with EPD and 12 patients with Bowen's disease seen at our clinic between 1993 and 2000. TGF-beta3 and p53 immunohistochemical staining was performed. RESULTS: In three of the 12 EPD patients and five of the 12 Bowen's disease patients, positive p53 staining was detected. In contrast, TGF-beta3 overexpression was detected in all EPD patients, whereas downregulated TGF-beta3 expression was detected in all Bowen's disease patients. CONCLUSIONS: The present data suggest different roles for TGF-beta3 in abnormal epidermal cells in EPD and Bowen's disease. Thus, TGF-beta3 expression may be modulated differently via a p53-dependent or -independent pathway in the pathogenesis of EPD and Bowen's disease. Moreover, high TGF-beta expression appears to be a useful indicator of tumor activity in EPD.

Aged↗
PubMed2001

Endoscopic management of a traumatic disruption of the bulbous urethra using a thin trocar puncture.

A case is reported in which complete disruption of the bulbous urethra resulted in a straddled-type injury, which was managed by endoscopic realignment with a thin trocar needle. The endoscopic urethroplasty consisted of: (i) direct observation of the proximal end of the obliterated urethra by an antegrade flexible cystoscope; (ii) adjustment of the direction of trocar penetration under fluoroscopy and direct vision; (iii) confirmation of the exact trocar position and penetration by antegrade flexible cystoscope; and (iv) placement of the guidewire following the trocar penetration as guidance for urethrotomy. A Foley catheter was left in place for 6 weeks. To date, no further endoscopic revision has been required. Although long-term follow up and more experience are required, this technique is reported because it appears to be safe, reproducible, simple and minimally invasive.

Cystoscopy↗
PubMed2001

Action-oriented support for occupational safety and health programs in some developing countries in Asia.

Action-oriented support programs have been increasingly playing vital roles in promoting safety and health in developing countries in Asia. This paper studied achievements of 3 action-oriented support programs: the WISE program for small enterprises, the WIND program for farmers, and the POSITIVE program for workers and trade unions. Special attention was paid to how the programs have strengthened local efforts for sustainable actions in safety and health improvements. The results showed that there were significant achievements in action-oriented support programs in the region, including a large number of improvement examples, integration into government policies, and network support through employers' and workers' organizations. Participatory, action-oriented training tools such as action-checklists, local good example photos, and group work methods played key roles in the effective implementation of the programs. It was of note that there were a number of local efforts to extend the coverage of action-oriented support even to hard-to-reach workers such as home-based workers, rural workers, and ethnic minorities. The efforts included the equal participation in the training by female and male farmers, shortened and weekend training programs, photo sheets showing local good examples, and reasonable fee collection for better sustainability. In conclusion, action-oriented support programs provided local people with concrete means to promote safety and health improvements. The successful programs commonly focused on local initiatives and were built on local wisdom and resources.

Asia↗
PubMed2001

Xenopus eggs express an identical DNA methyltransferase, Dnmt1, to somatic cells.

In mouse, an oocyte-specific short isoform of DNA methyltransferase-1 (Dnmt1) lacking amino terminal 118 amino acid residues exists and plays a crucial role in maintaining the methylation state of imprinted genes during early embryogenesis [Howell et al. (2001) Cell 104, 829-838]. To address the question of whether or not Xenopus oocyte expresses such a short isoform, we raised monoclonal antibodies against the amino-terminal portion of Xenopus Dnmt1. Two of the isolated monoclonal antibodies, 3C6 and 4A8, were determined to recognize (1-32) and (115-126) of Xenopus Dnmt1, respectively. The amounts of Dnmt1 in Xenopus eggs were determined to be similar, 10.0 2.5, 8.0 0.8, and 8.2 0.2 ng per egg with monoclonal antibodies 3C6 and 4A8, and polyclonal antibodies, respectively. This indicated that Dnmt1 in Xenopus mature eggs had an identical amino-terminal sequence to the amino acid sequence deduced from the cDNA. Together with the fact that Dnmt1 in A6 cells immuno-reacted with all the monoclonal antibodies isolated and with the polyclonal antibodies, we concluded that Dnmt1 expressed in Xenopus mature eggs possesses an identical amino-terminal sequence to that in somatic cells. Immuno-purified Xenopus Dnmt1 in mature eggs showed similar specific activity to that in proliferating A6 cells and that of mouse recombinant Dnmt1.

Amino Acid Sequence↗
PubMed2001

Low-concentration lidocaine rapidly inhibits axonal transport in cultured mouse dorsal root ganglion neurons.

BACKGROUND: Axonal transport plays a critical role in supplying materials for a variety of neuronal functions such as morphogenetic plasticity, synaptic transmission, and cell survival. In the current study, the authors investigated the effects of the analgesic agent lidocaine on axonal transport in neurites of cultured mouse dorsal root ganglion neurons. In relation to their effects, the effects of lidocaine on the growth rate of the neurite were also examined. METHODS: Isolated mouse dorsal root ganglion cells were cultured for 48 h until full growth of neurites. Video-enhanced microscopy was used to observe particles transported within neurites and to measure the neurite growth during control conditions and in the presence of lidocaine. RESULTS: Application of 30 microM lidocaine immediately reduced the number of particles transported in anterograde and retrograde axonal directions. These effects were persistently observed during the application (26 min) and were reversed by lidocaine washout. The inhibitory effect was dose-dependent at concentrations from 0.1 to 1,000 microM (IC50 = 10 microM). In Ca2+-free extracellular medium, lidocaine failed to inhibit axonal transport. Calcium ionophore A23187 (0.1 microM) reduced axonal transport in both directions. The inhibitory effects of lidocaine and A23187 were abrogated by 10 microM KN-62, a Ca2+-calmodulin-dependent protein kinase II inhibitor. Application of such low-concentration lidocaine (30 microM) for 30 min reduced the growth rate of neurites, and this effect was also blocked by KN-62. CONCLUSIONS: Low-concentration lidocaine rapidly inhibits axonal transport and neurite growth via activation of calmodulin-dependent protein kinase II.

Anesthetics, Local↗
PubMed2001

Distribution density of intraepidermal nerve fibers in normal human skin.

A total of 74 specimens was obtained from the normal human skin of patients from 3 to 90 years old. The specimens were roughly classified into 5 groups: 15 for the face group from the face; 15 for the abdomen group from the abdomen; 13 for the back group from the back; 14 for the arm group from the upper arm and forearm; and 17 for the leg group from the thigh and lower leg. They were all fixed in 4% paraformaldehyde and 14% saturated picric acid. Cryostat sections were examined by the immunoperoxidase method and indirect immunofluorescence (IF). Primary antibodies against neurofilament, neuron-specific enolase, protein gene product 9.5 (PGP 9.5) and S-100 protein were used. The most effective method was found to be the combination of IF with PGP 9.5; it visualized the intraepidermal nerve fibers easily and clearly. Of the 74 specimens, 32 (43%) had intraepidermal PGP 9.5-immunoreactive (or nerve) fibers (IPIF), and 42 (57%) did not have any. With reference to the different skin locations, the maximal rate of specimens having IPIF was 57% in the arm group, and the minimum was 23% in the back group. IPIF positive specimens had approximate surface lengths of 6 mm, in which the existence number of the IPIF was 1 to 75. Their distribution density per 1000 epidermal basal cells was highest at 9.63 in the arm group and lowest at 2.89 in the back group. Their thickness was 2.94 +/- 0.83 microns with no significant differences among the five groups. We concluded that intraepidermal nerve fibers may not be distributed evenly in the hairy portions of normal human skin, but they may be present focally. Physiologically, two-point discrimination of itch may be explained by the distribution mode of intraepidermal nerve fibers.

Adolescent↗
PubMed2001

Complete DNA sequence and comparative analysis of the 50-kilobase virulence plasmid of Salmonella enterica serovar Choleraesuis.

The complete nucleotide sequence of pKDSC50, a large virulence plasmid from Salmonella enterica serovar Choleraesuis strain RF-1, has been determined. We identified 48 of the open reading frames (ORFs) encoded by the 49,503-bp molecule. pKDSC50 encodes a known virulence-associated operon, the spv operon, which is composed of genes essential for systemic infection by nontyphoidal Salmonella. Analysis of the genetic organization of pKDSC50 suggests that the plasmid is composed of several virulence-associated genes, which include the spvRABCD genes, plasmid replication and maintenance genes, and one insertion sequence element. A second virulence-associated region including the pef (plasmid-encoded fimbria) operon and rck (resistance to complement killing) gene, which has been identified on the virulence plasmid of S. enterica serovar Typhimurium, was absent. Two different replicon regions, similar to the RepFIIA and RepFIB replicons, were found. Both showed high similarity to those of the pO157 plasmid of enterohemorrhagic Escherichia coli O157:H7 and the enteropathogenic E. coli (EPEC) adherence factor plasmid harbored by EPEC strain B171 (O111:NM), as well as the virulence plasmids of Salmonella serovars Typhimurium and Enteritidis. Comparative analysis of the nucleotide sequences of the 50-kb virulence plasmid of serovar Choleraesuis and the 94-kb virulence plasmid of serovar Typhimurium revealed that 47 out of 48 ORFs of the virulence plasmid of serovar Choleraesuis are highly homologous to the corresponding ORFs of the virulence plasmid of serovar Typhimurium, suggesting a common ancestry.

Base Sequence↗
PubMed2001

Analysis of p53, p21(Waf1/Cip1) and TGF-beta(3) immunohistochemical staining in Bowen's disease.

BACKGROUND: The p53 gene is one of a family of tumor suppressor genes that have been implicated in the genesis of a wide variety of malignant neoplasms including Bowen's disease. Its role in oncogenesis and tumor progression is thought to be of importance. Transforming growth factor beta (TGF-beta) is the most potent known inhibitor of the progression of normal epithelial cells through the cell cycle. p21(Waf1/Cip1) is thought to mediate p53 signaling induced by DNA-damaging agents to arrest the cell cycle. OBJECTIVE: The present study evaluates the expression of p53, p21(Waf1/Cip1) and TGF-beta(3) protein and speculates on their role in Bowen's disease. METHODS: Sixteen patients seen at our clinic between 1993 and 2000 were examined. We analyzed p21(Waf1/Cip1), p53 and TGF-beta(3) immunohistochemical staining in all specimens. RESULTS: In 7 of the Bowen's disease patients, overexpression of p53-positive cells was present in the middle and basal layers, and intense staining of p21(Waf1/Cip1) was observed in the upper spinous layers. In the other 9 Bowen's disease patients, we found positively stained cells for p21(Waf1/Cip1) but negative p53 immunostaining in the upper epidermal layer. Downregulated TGF-beta(3) expression was detected in all layers except the upper spinous layers. CONCLUSION: These observations suggest different roles for p21(Waf1/Cip1) and p53 within abnormal cells in Bowen's disease. p21(Waf1/Cip1) may induce terminal differentiation to the superficial layer in Bowen's disease via either a p53-independent or -dependent pathway. Moreover, downregualtion of TGF-beta(3) immunostaining provides relevant information concerning the pathogenesis of Bowen's disease.

Aged↗
PubMed2001

Safe and effective treatment of refractory facial lesions in atopic dermatitis using topical tacrolimus following corticosteroid discontinuation.

BACKGROUND: Topical corticosteroids are commonly applied in atopic dermatitis (AD) treatment. However, their chronic use may be associated with significant side effects at the application site. Skin atrophy and other undesirable effects are frequently seen after long-term corticosteroid treatment. In addition, when application of corticosteroids is discontinued, a rebound phenomenon in the facial lesions can occur within several days. Topical tacrolimus, an immunosuppressant currently used to prevent rejection after solid-organ transplantation, presents a potential alternative therapeutic agent for AD. OBJECTIVE: The present study is the first trial designed to evaluate the efficacy and safety of topically applied tacrolimus ointment after corticosteroid discontinuation without a washout phase in severe, long-term facial AD. PATIENTS/METHODS: Forty-seven patients with facial refractory AD were recruited, of whom 38 had undergone topical corticosteroid treatment for at least 4 weeks before enrollment (group 1) and the other 9 had not received steroid treatment (group 2). All 47 patients received 0.1% tacrolimus ointment, and the severity index and pruritus score were assessed as an AD clinical activity index every week and compared with baseline data. RESULTS: Both the severity index and pruritus score improved significantly in group 1 after 1 and 2 weeks of application (p < 0.01, respectively). Group 2 showed the greatest improvement at 4 weeks (p < 0.05). In this trial, none of the patients experienced a rebound phenomenon associated with tacrolimus treatment. A transient sensation of burning at the application site was the only adverse event in 31 of the 47 (66%) enrolled patients, but this condition improved after several days. Spectrophotometric assessment of the facial lesion following treatment revealed significant improvement in group 1 (p < 0.05). CONCLUSION: The present results indicate that topical tacrolimus treatment following corticosteroid discontinuation is safe and effective in refractory facial AD.

Administration, Topical↗
PubMed2001

Motion of the human mandibular condyle during mastication.

It has been reported that loading to the mandible during closing movement makes the condylar path move more in the superior direction than that during the free closing movement. In this study, the hypothesis was tested that the displacement of the condyle on the chewing side is greater in the direction of the mandibular fossa than that on the non-chewing side. Using a six-degrees-of-freedom jaw movement recording system, we recorded condylar motion in 12 healthy adults without TMD, during the chewing of a large hard gummy jelly. The maximum displacements at the condyle on the chewing side from the maximum intercuspation (CO) position were significantly larger in the superior and medial directions at the initial stage and in the posterior direction at all stages (0.5 mm, 0.5 mm, and 0.6 mm, respectively) than those on the non-chewing side (0.0 mm, 0.1 mm, and 0.1 mm, respectively). This suggests that, in healthy adults, the condyles at CO are located in a position such that excessive load is not applied to the temporomandibular joint when there are the aforementioned displacements.

Adult↗