Biomedical subjects
Publications and source records attributed to S Yamada.
We measured KL-6 concentrations in serum samples from measles patients with various forms of pneumonia and abnormally elevated levels of KL-6 were found exclusively in four fatal cases of pulmonary insufficiency.
In a new culture-conditioning system of agar-coated mesenchyme of isolated incisor dental papillae, dentinogenesis has been induced adjacent to an agar substratum that functions as a foothold for cell immobilisation. To elucidate the role of the basement membrane (BM) in dentinogenesis, we have examined the way in which dentinogenesis depends upon BM components or transforming growth factor (TGF)-beta1 in this system. At the mesenchymal-epithelial junction of odontogenic organs (cut incisor tooth germs), TGF-beta1 visibly increased in the BM during incubation. In isolated dental papillae, BM components were synthesised and deposited at aligned peripheral cells of the explants, together with an increasing amount of TGF-beta1. These components were not assembled into extracellular matrix (ECM)-absorbed agar adjacent to explants, although dentinogenesis proceeded in the presence of pericellular BM components associated with TGF-beta1. When signalling via TGF-beta type II receptors was blocked, neither ECM production nor dentinogenesis was observed but explants partially detached from the agar surface, presumably as a result of the suppressed production of ECM, since attachment was retained by pre-coating explants with artificial matrices. Rescue experiments showed that TGF-beta1 regulated dentinogenesis through ECM production. With regard to BM components, inducible dentinogenesis was Arg-Gly-Asp (RGD)-dependent. Thus, pericellular BM components associated with TGF-beta1 and an ECM-absorbed agar substratum, which affects dentinogenesis, synergistically play a role similar to that of BM components in vivo. The BM therefore serves as a structural meshwork that acts as a foothold for cell immobilisation; its components act as ligands for RGD-dependent cell adhesion and it stores TGF-beta1, which regulates ECM production.
BACKGROUND: This study was designed to compare genetic differences in single-nucleotide polymorphisms of the S-mephenytoin 4'-hydroxylation (CYP2C19) gene among four Asian populations. METHODS: Polymerase chain reaction with restriction fragment length polymorphism (PCR-RFLP) analysis of CYP2C19 was conducted in Japanese, Chinese, Thai, and Vietnamese populations. All genotype frequencies were analyzed. Wild-type homozygote and wild-type heterozygote genotypes were extensive proton pump inhibitor (PPI) metabolizers. Mutant-type heterozygote and mutant-type homozygote genotypes were poor PPI metabolizers. RESULTS: No significant differences in CYP2C19 phenotype, calculated based on genotype frequencies, (P > 0.05) were found among the four populations. CONCLUSIONS: Many factors, including CYP2C19 polymorphisms, affect the success rate of Helicobacterpylori eradication with PPI-based therapy. We suspect that CYP2C19 polymorphisms may not be the main factor associated with differences among these four Asian populations in the success rates of H. pylori eradication with PPI-based therapy.
BACKGROUND: Helicobacter pylori infection is associated not only with gastroduodenal ulcers but with the development of gastric cancer. Interleukin-1 beta (IL-1 beta) is a potent inhibitor of gastric secretion. The -31 C-to-T base transition in the intron of this gene has been reported to be involved in carcinogenic changes within the stomach, especially in H. pylori-infected individuals. METHODS: In this study, the -511 T-to-C polymorphism in the IL-1 beta gene was investigated in 669 patients with gastric diseases. RESULTS: The allelic frequencies of the C allele, which indicates low acid secretion and is a component of a supposedly high-risk genotype for gastric cancer, were 0.48 in H. pylori-negative noncancer controls, 0.52 in H. pylori-positive noncancer controls, 0.57 in subjects with chronic active gastritis (CAG) with H. pylori, 0.58 in subjects with intestinal metaplasia (IM) or CAG without H. pylori, and 0.52 in gastric cancer patients. Significant differences among the groups were observed between the IM or CAG without H. pylori group and the gastric cancer group and between the IM or CAG without H. pylori group and the H. pylori-negative noncancer control group (P < 0.05). CONCLUSIONS: The IL-1 beta-511 genetic polymorphism was not associated with gastric cancer in a multistep carcinogenesis model. However, in view of the results for the IM or CAG without H. pylori group, the presence of the C allele may also indicate a risk of mucosal atrophy of the stomach in the Japanese population.
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The antidepressant-like activity of a novel compound, OPC-14523, was investigated in comparison with the conventional antidepressants, fluoxetine and imipramine. OPC-14523 bound with nanomolar affinities to sigma receptors (IC(50)=47-56 nM), the 5-HT(1A) receptor (IC(50)=2.3 nM), and the 5-HT transporter (IC(50)=80 nM). OPC-14523 inhibited the in vitro reuptake of 3H-5-HT (IC(50)=27 nM), but it showed very weak inhibitory activity on 3H-NE and 3H-DA reuptake. OPC-14523 did not inhibit MAO A or B activities or muscarinic receptors. A single oral administration of OPC-14523 produced a marked antidepressant-like effect in the forced swimming test (FST) with rats (ED(50)=27 mg/kg) and mice (ED(50)=20mg/kg) without affecting the general locomotor activity. In contrast, fluoxetine and imipramine each required at least four days of repeated dosing to show this activity. The acute activity of OPC-14523 was blocked by pretreatment with the sigma receptor antagonist NE-100 or the selective 5-HT(1A) receptor antagonist WAY-100635. The induction of flat body posture by OPC-14523 was blocked by the selective 5-HT(1A) receptor antagonist NAN-190, and forebrain 5-HT biosynthesis was attenuated by OPC-14523 at behaviorally effective doses. In contrast, OPC-14523, unlike fluoxetine, failed to inhibit 5-HT reuptake at oral doses below 100mg/kg. Thus, the acute antidepressant-like action of OPC-14523 is achieved by the combined stimulation of sigma and 5-HT(1A) receptors without inhibition of 5-HT reuptake in vivo.
'Independent component analysis' is a technique of data transformation that finds independent sources of activity in recorded mixtures of sources. It can be used to recover fluctuations of membrane potential from individual neurons in multiple-detector optical recordings. There are some examples in which more than 100 neurons can be separated simultaneously. Independent component analysis automatically separates overlapping action potentials, recovers action potentials of different sizes from the same neuron, removes artifacts and finds the position of each neuron on the detector array. One limitation is that the number of sources--neurons and artifacts--must be equal to or less than the number of simultaneous recordings. Independent component analysis also has many other applications in neuroscience including, removal of artifacts from EEG data, identification of spatially independent brain regions in fMRI recordings and determination of population codes in multi-unit recordings.
PURPOSE: To evaluate the treatment outcome of radiation therapy for 33 loco-regionally recurrent esophageal cancer patients. METHODS: Between 1988 and 1997, 33 patients with loco-regional recurrence of esophageal cancer after curative surgery received radiation therapy at an average total dose of 61 Gy. The site of recurrence was the supraclavicular region in 14 patients, the mediastinal region in 13 patients, and both the supraclavicular and mediastinal regions in six patients. If patients had ether distant metastasis or malignant pleural effusion, they were excluded from analysis. Patients who received prophylactic postoperative irradiation were also excluded from analysis. RESULTS: The median survival period was 7 months. The survival rates at 1, 2, and 3 years were 33, 15, and 12%, respectively. In univariate analysis, patients with a short time interval between surgery and recurrence (P=0.0098) and patients with recurrence in both the supraclavicular and mediastinal regions (P=0.036) had a worse prognosis. In multivariate analysis, the time interval between surgery and recurrence (P<0.001) and age (worse prognosis in younger patients, P=0.019) were the significant prognostic factors. Complete or partial responses were observed in nine (27%) and 21 (64%) of the patients, respectively. Changes in clinical symptoms, such as dysphagia, chest pain and back pain, could be evaluated in 11 patients, and improvement in symptoms was obtained in eight (73%) patients. CONCLUSIONS: The prognosis of patients who received radiation therapy for postoperative loco-regional recurrence of esophageal cancer is poor. However, there is symptomatic relief in a significant proportion of such patients, and long-term survival is possible in some patients.
Three-dimensional structure of the ligand binding domain (LBD) of the vitamin D receptor (VDR) docked with the natural ligand 1 alpha,25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] has been mostly solved by the X-ray crystallographic analysis of the deletion mutant (VDR-LBD Delta 165-215). The important focus, from now on, is how the VDR recognizes and interacts with potent synthetic ligands. We now report the docking models of the VDR with three functionally and structurally interesting ligands, 22-oxa-1,25-(OH)(2)D(3) (OCT), 20-epi-1,25-(OH)(2)D(3) and 20-epi-22-oxa-24,26,27-trihomo-1,25-(OH)(2)D(3). In parallel with the computational docking studies, we prepared twelve one-point mutants of amino acid residues lining the ligand binding pocket of the VDR and examined their transactivation potency induced by 1,25-(OH)(2)D(3) and these synthetic ligands. The results indicate that L233, R274, W286, H397 and Y401 are essential for holding the all ligands tested, S278 and Q400 are not important at all, and the importance of S237, V234, S275, C288 and H305 is variable depending on the side-chain structure of the ligands. Based on these studies, we suggested key structural factors to bestow the selective action on OCT and the augmented activities on 20-epi-ligands. Furthermore, the docking models coincided well with our proposed active space-region theory of vitamin D based on the conformational analyses of ligands.
The aims of this study were to clarify the origin of DNA in human serum and to investigate whether serum is a material available for DNA typing in routine forensic practice. Blood was donated from 10 healthy adult volunteers and stored for up to 8 days, at 4 degrees C and at room temperature. The serum DNA concentration at zero time was in the range of 5.6 to 21.8 ng/ml with a mean of 12.2+/-1.6 ng/ml. The concentrations increased with storage time. On agarose gel electrophoresis, all serum samples showed ladder patterns and the size of each band was an integer multiple of approximately 180 bp considered to be characteristic of apoptosis. DNA typing from DNA released by apoptosis was possible. Exact DNA typing of D1S80, HLA DQA1, PM, CSF1PO, TPOX, TH01 and vWA was possible for each sample. These results indicate that serum contains fragmented DNA derived from apoptosis of leukocytes, especially neutrophils, and that fragmented DNA is an appropriate material for DNA typing.
Host immunomodulation through T cell action may play a pivotal role in determining the response to interferon (IFN) therapy for chronic hepatitis C. We examined whether the early changes in the host immune response were helpful in predicting the final effect in 31 patients with chronic hepatitis C receiving IFN. IFN treatment significantly reduced the serum levels of intercellular adhesion molecule-1 (ICAM-1) and E-selectin, and significantly increased those of vascular cell adhesion molecule-1 (VCAM-1) and interleukin-2 receptor alpha (IL-2Ralpha) in the first 7-10 days. Serum levels of these immunological parameters did not correlate with serum alanine aminotransferase (ALT) when evaluated with either absolute values or relative values (over pre-treatment value), implying that our results are not just secondary to improvement in hepatic inflammation. The relative changes (Delta) in these parameters reflected the long-term response to IFN therapy, i.e. the lower the change, the more effective the therapy was. Among these serum parameters, DeltaIL-2Ralpha within the first 7-10 days of IFN treatment was the most useful parameter in predicting the response to therapy. In conclusion, a dynamic immunomodulation during the early phase of IFN therapy may determine the subsequent long-term response to IFN therapy.
The comonomer compositional distribution and thermal and morphological characteristics were investigated for five bacterially synthesized poly(3-hydroxybutyrate-co-3-hydroxyvalerate) [P(3HB-co-3HV)] samples with 3HV content of 45, 49, 70, 80, and 96 mol %. All these samples were fractionated into many fractions with widely different 3HV content by changing solvent/nonsolvent volume ratio of chloroform/n-heptane mixtures. Bacterial P(3HB-co-3HV) samples investigated in this study were found to have broad comonomer compositional distribution. The tendencies of the fractional precipitation of the P((3HB-co-3HV)s with 3HV content lower than 60 mol % and those with 3HV higher than 80 mol % were found to be contrary. The 3HV content dependences of the thermal properties and crystalline structures were investigated for bacterial poly(3-hydroxybutyrate) [P(3HB)] and a series of compositionally well-fractionated P(3HB-co-3HV) samples with 3HV content ranged from 14 to 98 mol % by DSC, WAXD, and solid-state (13)C NMR. It was found that P(3HB-co-3HV) samples with 3HV content lower than about 47 mol % form the crystalline lattice having the P(3HB) homopolymer type lattice including the 3HV unit as the crystal constituent, and those with a 3HV content higher than about 52 mol % form the crystalline lattice having the P(3HV) homopolymer type lattice including the 3HB units. Thus, P(3HB-co-3HV)s show the crystalline structural change in a very narrow range of 3HV content.
Gliomatosis cerebri is considered grade III astrocytoma because of the short survival period of patients with this tumor, while the tumor histologically consists of widespread low grade astrocytoma cells. The authors tried to clarify this discrepancy by applying genetic analysis of the tumor. A 29-year-old man originally presented with mild headache and showed diffuse high intensity areas in both hemispheres and in the cerebellum by T2-weighted magnetic resonance imaging (MRI) without gadolinium-dimeglumine (Gd)-enhancement in T1-weighted imaging. Histological diagnosis was gliomatosis cerebri with diffuse grade II astrocytoma. Seven months after temporary improvement following irradiation and chemotherapy, he developed progressive mental deterioration, and died in one year after the surgery. At this time T1-weighted imaging showed Gd-enhanced lesions with enlargement only of the cerebellar tumor. Genetic analysis demonstrated positive FGFR 1 and less FGFR 2 mRNA in the tumor tissue, and FGFR 1 mRNA was beta type dominant. These results indicated that the genetic features of this tumor are similar to those of glioblastoma multiforme concerning FGFR expression. The authors conclude that genetic investigation of the tumor tissue is required to predict the prognosis of gliomatosis cerebri patients, in addition to imaging and histological examinations.
PURPOSE: We investigated a role of long-wavelength red light emission from TV in the induction of photosensitive seizures by an animated TV program called "Pocket Monsters". METHODS: The luminance energy of recorded color bar was measured by a spectroradiometer in cathode-ray tubes (CRTs) of photosensitive patients with and without seizures on the program (induced patients and photosensitive controls). RESULTS: The mean ratio of long-wavelength red light to total visible range was significantly higher in the CRTs of induced patients than in the CRTs of photosensitive controls. The ratio of luminance energy between at turn-on and at 60 min after turn-on of the CRTs indicated that luminance energy in long-wavelength red range from the CRTs of induced patients increased significantly after turn-on of CRTs. CONCLUSIONS: High amounts of long-wavelength red light emitted from CRTs might play an important role in induction of photosensitive seizures in "Pokemon" incident.
Keratins 5 and 14 polymerize to form the intermediate filament network in the progenitor basal cells of many stratified epithelia including epidermis, where it provides crucial mechanical support. Inherited mutations in K5 or K14 result in epidermolysis bullosa simplex (EBS), a skin-fragility disorder. The impact that such mutations exert on the intrinsic mechanical properties of K5/K14 filaments is unknown. Here we show, by using differential interference contrast microscopy, that a 'hot-spot' mutation in K14 greatly reduces the ability of reconstituted mutant filaments to bundle under crosslinking conditions. Rheological assays measure similar small-deformation mechanical responses for crosslinked solutions of wild-type and mutant keratins. The mutation, however, markedly reduces the resilience of crosslinked networks against large deformations. Single-particle tracking, which probes the local organization of filament networks, shows that the mutant polymer exhibits highly heterogeneous structures compared to those of wild-type filaments. Our results indicate that the fragility of epithelial cells expressing mutant keratin may result from an impaired ability of keratin polymers to be crosslinked into a functional network.
Urinary trypsin inhibitor has attracted attention as an index of the systemic inflammatory response syndrome. In this study, the urine concentration of trypsin inhibitor was measured to compare the immunological insult of conventional chemotherapy and conditioning chemotherapy for bone marrow transplantation. We also investigated whether urinary trypsin inhibitor was a useful index of the complications and outcome of bone marrow transplantation. Urinary trypsin inhibitor concentration was determined before chemotherapy, on the day after finishing chemotherapy (day 0 of transplantation), and during recovery of the white cell count, in 17 patients (seven receiving conventional chemotherapy and 10 receiving conditioning for bone marrow transplantation). Urinary trypsin inhibitor concentrations were significantly higher after conditioning for bone marrow transplantation than after conventional chemotherapy (P < 0.001), indicating that conditioning was more invasive. After bone marrow transplantation, the incidence of severe complications and the mortality rate were higher in patients whose urinary trypsin inhibitor concentrations rose during recovery of the white cell count. Comparison of urinary trypsin inhibitor concentrations suggested that conditioning for bone marrow transplantation was more invasive than conventional chemotherapy. This study also suggested that the urine concentration of trypsin inhibitor could be useful for predicting the risk of complications and outcome of bone marrow transplantation.
To evaluate the efficacy of long-term administration of acyclovir as prophylaxis against varicella-zoster virus (VZV) reactivation, we analyzed the medical records of 86 consecutive adult patients who obtained engraftment after allogeneic hematopoietic stem cell transplantation from January 1996 to March 2000. We started long-term low-dose (400 mg/day) oral administration of acyclovir in June 1999, and this was continued until the end of immunosuppressive therapy after transplantation. There was no breakthrough reactivation of VZV in patients receiving acyclovir. Five patients who were receiving cyclosporine or prednisolone developed VZV reactivation after discontinuing acyclovir. With this prophylaxis, the cumulative incidence of VZV reactivation at 1 year after transplantation decreased from 33% to 10% (P = 0.025). On multivariate analysis, the use of long-term acyclovir was identified as a significant independent parameter for the development of VZV reactivation. These findings suggest the efficacy of long-term prophylaxis with low-dose acyclovir. Resumption of acyclovir upon restarting immunosuppressive therapy might be important for the further prevention of VZV reactivation. The benefit of long-term low-dose acyclovir should be confirmed prospectively.
To determine the clinical relevance of in vitro drug chemoresistance in childhood acute myeloid leukemia, we used an MTT assay to test leukemic cells from 132 newly diagnosed children. Patients were diagnosed according to the French-American-British (FAB) classification as follows: M0 (n = 12), M1 (n = 16), M2 (n = 53), M4 (n = 17), M5 (n = 19) and M7 (n = 15). The results revealed that, compared to leukemic cells from complete-responders (n = 107), those from non-responders who failed induction therapy (n = 17) were 1.4 to 5.0 times more resistant in vitro to cytarabine (P = 0.005), melphalan (P = 0.003), etoposide (P = 0.011), L-asparaginase (P = 0.017), aclarubicin (P = 0.026) and dexamethasone (P = 0.039). For seven other drugs tested, the median lethal dose of 70% and leukemic cell survival of non-responders were higher than those of complete-responders, but the difference was not statistically significant. We sought correlations between FAB subtypes and in vitro drug resistance. Leukemias of the FAB M4 and M5 subtype were more sensitive to L-asparaginase (P = 0.01, P = 0.0036) than those of the FAB M2 subtype. FAB M5 leukemia was more sensitive to etoposide than were the FAB M2, M4 and M7 subtypes (P = 0.001, P = 0.034, P = 0.023, respectively). By contrast, FAB M5 leukemia was significantly more resistant to prednisolone and dexamethasone than were the FAB M0, M1, M2, M4 and M7 subtypes. We sought correlations between in vitro drug resistance and long-term clinical outcome, but found no associations in this case. These results suggest that in vitro resistance to cytarabine, melphalan, etoposide, L-asparaginase, aclarubicin and dexamethasone might represent factors that can predict response to the early course of therapy. Selecting an appropriate anti-cancer drug according to the FAB classification together with drug sensitivity testing may contribute to improved prognoses in childhood acute myeloid leukemia.