Biomedical subjects
Publications and source records attributed to A Honda.
We describe an 86-year-old man with Bowen's disease on the pubic area. The lesion was clinically a black-brownish keratotic nodule resembling seborrheic keratosis. Histopathological findings showed those of Bowen's disease and harboured human papillomavirus type 34 DNA. Genital, but not skin, human papillomaviruses are responsible for Bowen's disease on the skin.
Dehydroepiandrosterone (DHEA) is the most abundant adrenal androgenic steroid in young adult humans. The physiological functions of DHEA in preventing human carcinogenesis are still controversial, but a lot of reports have shown that pharmacological doses of DHEA show chemopreventive and anti-proliferative effects on tumors in rodents. Although a therapeutic dose of DHEA has been reported to promote hepatocarcinogenesis in rats due to peroxisomal proliferation, it remains unclear whether DHEA is a peroxisome proliferator in human liver. The chemopreventive and anti-proliferative effects of DHEA are not explained by a single mechanism, and at least four mechanisms seem to contribute to these effects: 1) depletion of NADPH and ribose-5-phosphate due to the inhibition of glucose-6-phosphate dehydrogenase activity, 2) suppression of cholesterol biosynthetic pathway by inhibition of HMG-CoA reductase, 3) interference with cell proliferation signaling pathways, and 4) suppression of nitric oxide generation through down-regulation of nitric oxide synthase II. In addition to studies of the mechanisms underlying the anti-neoplastic effects, searches for more potent and less androgenic DHEA derivatives are ongoing. A small amount of DHEA is endogenously metabolized to 7-oxygenated DHEA, and this may represent a metabolic pathway to more potent steroid hormones. Androsterone, epiandrosterone and etiocholanolone have been considered to be merely inactive end products of DHEA, but may in fact be physiological effectors in their own right. In addition, DHEA analogs such as 3beta-methyl-5-androsten-17-one, 16alpha-fluoro-5-androsten-17-one and 16alpha-fluoro-5alpha-androstan-17-one have been synthesized and shown to be more effective inhibitors of tumor growth, compared with DHEA itself. However, to design potent and safe DHEA derivatives, identification of the DHEA receptor and clarification of the mechanisms of DHEA action are required.
We have demonstrated that serum macrophage migration inhibitory factor (MIF) was significantly elevated in patients with extensive alopecia areata (AA). Recently, functional polymorphisms have been identified in the MIF promoter region. To address the functional and prognostic relevance of the -173G/C and -794[CATT]5-8 repeat polymorphisms in MIF genes in patients with extensive AA, 113 patients with extensive AA and 194 healthy controls were genotyped. We found that MIF-173*C was a risk factor for early onset (<20 years) of extensive AA (odds ratio for GC heterozygotes with -173G/C was 4.88 (95% CI, 2.04-11.8), P=0.00038; odds ratio for CC homozygotes with -173G/C was 10.42 (95% CI, 2.56-43.5), P=0.0011). We found no statistically significant differences in the genotype frequencies of the -794[CATT]5-8 repeat polymorphism and extensive AA. These results suggest that polymorphisms within the MIF-173*C allele confer an increased risk of susceptibility to the extensive forms of AA, especially with an early onset of disease. MIF is therefore suggested to be closely implicated in the pathogenesis of the more extensive forms of AA.
Arfs are a family of Ras-related GTP-binding proteins that function in the regulation of membrane trafficking and structure. The six mammalian Arf proteins are expressed ubiquitously and so it is anticipated that each will have a distinct localization and function within the cell. It has been assumed that much of this specificity will be defined by determining which regulators of Arfs, the GEFs (guanine nucleotide-exchange factors) and GAPs (GTPase-activating proteins) function with which Arf proteins. Although in vitro assays may indicate Arf preferences for the numerous Arf GEFs and GAPs that have been identified, in the cell the different Arfs, GEFs and GAPs are targeted to specific compartments where they carry out their functions. We have embarked on studies to define regions of the Arf1 and Arf6 proteins that determine their sites of action and specific activities at the Golgi and plasma membrane respectively. Chimaeras were made between Arf1 and Arf6 in order to identify regions of the protein that contributed to targeting and function. Whereas Arf6 is targeted to the plasma membrane through multiple regions along the protein, we have found a Golgi-targeting region in Arf1 that is sufficient to target Arf6 to the Golgi complex.
Tobacco plants expressing the mammalian 2'5'oligoadenylate system (2-5A system) exhibit resistance to cucumber mosaic virus (CMV). Here, to characterize the molecular aspect of the resistance to CMV in 2-5A system-expressing tobaccos, the activation of defense-related genes and systemic acquired resistance (SAR) as the markers for the hypersensitive resistance (HR), were elucidated. Northern hybridization analysis indicated that the expression of four pathogenesis-related (PR) protein genes and five HR-related genes were induced in CMV-infected tobaccos expressing 2-5A system. Furthermore, the induction of SAR against Pseudomonas syringae pv. tabaci as second challenge, was observed on CMV-inoculated tobaccos expressing 2-5A system. These results suggested that the resistance to CMV in tobacco expressing 2-5A system is associated with the establishment of an HR-like response.
The aberrant splicing isoform (PS2V), generated by exon 5 skipping of the Presenilin-2 (PS2) gene transcript, is a diagnostic feature of sporadic Alzheimer's disease (AD). We found PS2V is hypoxia-inducible in human neuroblastoma SK-N-SH cells. We purified a responsible trans-acting factor based on its binding to an exon 5 fragment. The factor was identified as the high mobility group A1a protein (HMGA1a; formerly HMG-I). HMGA1a bound to a specific sequence on exon 5, located upstream of the 5' splice site. HMGA1a expression was induced by hypoxia and the protein was accumulated in the nuclear speckles with the endogenous splicing factor SC35. Overexpression of HMGA1a generated PS2V, but PS2V was repressed by cotransfection with the U1 snRNP 70K protein that has a strong affinity to HMGA1a. HMGA1a could interfere with U1 snRNP binding to the 5' splice site and caused exon 5 skipping. HMGA1a levels were significantly increased in the brain tissue from sporadic AD patients. We propose a novel mechanism of sporadic AD that involves HMGA1a-induced aberrant splicing of PS2 pre-mRNA in the absence of any mutations.
Disrupted-In-Schizophrenia 1 (DISC1) was identified as a novel gene disrupted by a (1;11)(q42.1;q14.3) translocation that segregated with schizophrenia in a Scottish family. Predicted DISC1 product has no significant homology to other known proteins. Here, we demonstrated the existence of DISC1 protein and identified fasciculation and elongation protein zeta-1 (FEZ1) as an interacting partner of DISC1 by a yeast two-hybrid study. FEZ1 and its nematode homolog are reported to represent a new protein family involved in axonal outgrowth and fasciculation. In cultured hippocampal neurons, DISC1 and FEZ1 colocalized in growth cones. Interactions of these proteins were associated with F-actin. In the course of neuronal differentiation of PC12 cells, upregulation of DISC1/FEZ1 interaction was observed as along with enhanced extension of neurites by overexpression of DISC1. The present study shows that DISC1 participates in neurite outgrowth through its interaction with FEZ1. Recent studies have provided reliable evidence that schizophrenia is a neurodevelopmental disorder. As there is a high level of DISC1 expression in developing rat brain, dysfunction of DISC1 may confer susceptibility to psychiatric illnesses through abnormal development of the nervous system.
After greater than 60 gray (Gy) irradiation, we performed the pulmonary resection in the 18 primary lung cancer cases. The mean irradiation dose to the tumor was 68.2 (range 60-101) Gy, and the mean irradiation dose to the bronchial stump was 47.1 (range 0-82) Gy. Median time from end of irradiation to surgical resection was 136 (range 20-894) days. One partial resection, 9 single lobectomies, 3 double lobectomies, and 5 pneumonectomies were done. Mainly, we closed the bronchial stump by the automatic stapling device and additional hand suturing. The bronchial stump was covered in the 12 cases by the owner stalk thymus, the intercostals muscular flap, the omentum flap, and et al. The major postoperative complications due to preoperative irradiation were not seen. Bronchopleural fistulas did not occur. Pathologically, the wall of the submucosal capillary vessels were getting thick in the patients operated more than 3 months later after irradiation. In such cases with the decrease of the blood flow, the bronchial stump should be covered. The pulmonary resection after the high dose irradiation was considered to be tolerable.
OBJECTIVE: To elucidate the effect of multiple pregnancies on lumbar spine bone mineral density (BMD). METHODS: The BMD of the lumbar spines (L2-L4) of 1,113 healthy women was measured within 7 days of childbirth. In addition 113 women had spine BMD measurements after their next delivery. RESULTS: In the cross-sectional study, there was no apparent effect of parity on lumbar BMD. In the longitudinal study, the mean BMD after the next delivery was significantly higher than that after the initial delivery (1.019 +/- 0.115 g/cm(2) vs. 1.006 +/- 0.117 g/cm(2), P = 0.001, paired t test) with a percent change (DeltaBMD%) of 1.4 +/- 4.2%. Multiple regression analysis to identify independent predictors of DeltaBMD% showed a negative correlation with maternal age at the subsequent delivery (P = 0.033) but no correlation of DeltaBMD% with the length of lactation between the scans. CONCLUSION: Multiple pregnancies may not reduce maternal lumbar BMD, although the percentage decrease in BMD was greater in older women at the subsequent delivery. The length of lactation between the scans had no effect on these results.
Abstract. The effects of cessation of high-impact exercise on bone mass in female Wistar rats was assessed. Fifty 10-week old rats were randomly divided into five groups (n = 10): 4 weeks jump-exercise (4JEX), 4 weeks sedentary control (4S), 8 weeks jump-exercise (8JEX), 4 weeks jump-exercise followed by 4 weeks sedentary (4JEX4S) and 8 weeks sedentary control (8S). The rats were jumped trained 40 times/session, 5 days/week. After 4 weeks or 8 weeks the mass and breaking force in tibia and cross-sectional areas of the tibia were measured. The tibia in the 4JEX and 8JEX groups had significantly greater fat-free dry weight and maximum loads at the fracture tests than those in the 4S and 8S groups. The tibia of 4JEX and 8JEX also had significantly larger cortical area without a significant change in the medullary area at the cross-sectional analysis. Bone mass acquired in 4JEX4S group was retained after cessation of exercise. The results indicate that high-impact jump-exercise, which is osteotropic, leads to an increased cortical bone with enhanced periosteal bone formation, which is also, however, maintained after cessation of exercise. It is therefore suggested that high-impact jump-exercise may provide greater safety margin against disuse-related or/and age-related bone loss and skeletal fragility later in life.
In this study, we evaluated the anti-obesity effects of selective beta3 adrenergic receptor agonist (ARa) and/or a diet in oophorectomized (OVX) treatment in obese rats. Ten-week-old female Sprague-Dawley rats were divided into 4 groups: (1) OVX; (2) OVX treated with beta3 ARa, BRL 35 135; (3) sham-operated controls (sham group); (4) sham-treated with beta3 ARa (sham+ARa group). These four groups were divided into two groups, one on ad libitum diet, and the other on a diet of limited chow. The effects of beta3 ARa on body weight, intraabdominal fat weight, adipocyte volume, serum lipid content, and serum leptin were measured after 4 weeks had been completed. On both the ad libitum and the limited diet, ARa significantly reduced the ratio of intraabdominal fat and body weight (IAF ratio) regardless whether in the OVX or sham group, although ARa had no influence on weight gain. On the ad libitum diet, the serum leptin was significantly increased after OVX, and significantly reduced after ARa administration. ARa significantly reduced the volume of intraabdominal adipocytes. We conclude that ARa reduces intraabdominal fat without reducing body weight in oophorectomized rats. The serum parameter affected differently to rats on the ad libitum diet and on the limited diet.
Angiosarcomas rarely develop within a peripheral nerve or a peripheral nerve sheath tumor. A 68-year-old woman was admitted for right hemothorax. She had suffered from the left thoracic empyema and the right chest wall tumor which had been regarded as schwannoma clinically. Anemia got serious due to continuous bloody effusion. Although bleeding point was not detected by thoracotomy. The right chest wall tumor was resected. Postoperatively bloody effusion still drained continuously, she died ten days after the operation. Resected tumor was almost necrotized. The tumor was diagnosed as angiosarcoma pathologically, in which a part of schwannoma component resided. It is indicated that angiosarcoma in this case arised from degenerated schwannoma. It is necessary to consider angiosarcoma, rarely arised from degenerated schwannoma, during conservative, long-term observation on the care of schwannoma.
A female infant with isolated noncompaction of ventricular myocardium who developed ventricular tachyarrhythmia is described. Wolff-Parkinson-White syndrome was shown by electrocardiography. At 9 months of age, the patient suddenly developed cardiac arrest. Electrocardiography following resuscitation with DC cardioversion demonstrated sinus rhythm without delta wave. The QT interval was normal. Frequent premature ventricular captures caused ventricular fibrillation. DC cardioversion was necessary to terminate frequent attacks of ventricular fibrillation until the introduction of beta blockers and lidocaine. Two-dimensional echocardiogram confirmed the diagnosis of isolated non-compaction of ventricular myocardium. Three months later, the patient died of ventricular fibrillation during respiratory syncytial viral infection.
Recent studies have shown independently that presenilin-1 (PS1) null mutants and familial Alzheimer's disease (FAD)-linked mutants should both down-regulate signaling of the unfolded protein response (UPR). However, it is difficult to accept that both mutants possess the same effects on the UPR. Furthermore, contrary to these observations, neither loss of PS1 and PS2 function nor expression of FAD-linked PS1 mutants were reported to have a discernable impact on the UPR. Therefore, re-examination and detailed analyses are needed to clarify the relationship between PS1 function and UPR signaling. Here, we report that PS1/PS2 null and dominant negative PS1 mutants, which are mutated at aspartate residue 257 or 385, did not affect signaling of the UPR. In contrast, FAD-linked PS1 mutants were confirmed to disturb UPR signaling by inhibiting activation of both Ire1alpha and ATF6, both of which are endoplasmic reticulum (ER) stress transducers in the UPR. Furthermore, PS1 mutants also disturbed activation of PERK (PKR-like ER kinase), which plays a crucial role in inhibiting translation during ER stress. Taken together, these observations suggested that PS1 mutations could affect signaling pathways controlled by each of the respective ER-stress transducers, possibly through a gain-of-function.
The accumulation of various 25-hydroxylated C(27)-bile alcohols in blood and their excretion in urine are characteristic features of cerebrotendinous xanthomatosis (CTX) a recessively inherited inborn error of bile acid synthesis caused by mutations in the mitochondrial sterol 27-hydroxylase (CYP27) gene. These bile alcohols may be intermediates in the alternative cholic acid side chain cleavage pathway. The present study was undertaken to identify enzymes and reactions responsible for the formation of these bile alcohols and to explain why Cyp27(-/-) mice do not show CTX-related abnormalities. Microsomal activities of 5beta-cholestane-3alpha,7alpha,12alpha-triol 25- and 26-hydroxylases, 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol 23R-, 24S-, and 27-hydroxylases and testosterone 6beta-hydroxylase, a marker enzyme for CYP3A, in Cyp27(-/-) mice livers were markedly up-regulated (5.5-, 3.5-, 6.5-, 7.5-, 2.9-, and 5.4-fold, respectively). In contrast, these enzyme activities were not increased in CTX. The activities of 5beta-cholestane-3alpha,7alpha,12alpha-triol 25- and 26-hydroxylases and 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol 23R-, 24R-, 24S-, and 27-hydroxylases were strongly correlated with the activities of testosterone 6beta-hydroxylase in control human liver microsomes from eight unrelated donors. Troleandomycin, a specific inhibitor of CYP3A, markedly suppressed these microsomal side chain hydroxylations in both mouse and human livers in a dose-dependent manner. In addition, experiments using recombinant overexpressed human CYP3A4 confirmed that these microsomal side chain hydroxylations were catalyzed by a single enzyme, CYP3A4. The results demonstrate that microsomal 25- and 26-hydroxylations of 5beta-cholestane-3alpha,7alpha,12alpha-triol and microsomal 23R-, 24R-, 24S-, and 27-hydroxylations of 5beta-cholestane-3alpha,7alpha,12alpha,25-tetrol are mainly catalyzed by CYP3A in both mice and humans. Unlike Cyp27(-/-) mice, CYP3A activity was not up-regulated despite marked accumulation of 5beta-cholestane-3alpha,7alpha,12alpha-triol in CTX.
The RNA-dependent RNA polymerase of influenza virus is composed of three viral P proteins (PB1, PB2, and PA) and involved in both transcription and replication of the RNA genome. For the molecular anatomy of this multifunctional enzyme, we have established a simultaneous expression of three P proteins in cultured insect cells using recombinant baculoviruses. For purification of P protein complexes, the PA protein was expressed as a fusion with a histidine tag added at its N terminus. By using affinity chromatography, a complex consisting of the three P proteins was isolated from nuclear extracts of virus-infected cells. The affinity-purified 3P complex showed the activities of capped RNA binding, capped RNA cleavage, viral model RNA binding, model RNA-directed RNA synthesis, and polyadenylation of newly synthesized RNA. We conclude that a functional form of the viral RNA polymerase with the catalytic specificity of transcriptase is formed in recombinant baculovirus-infected insect cells. Using the viral RNA-free 3P complex, we found that the capped RNA cleavage takes place in the presence of vRNA but not of cRNA, indicating that the vRNA functions as a regulatory factor for the specificity control of viral RNA polymerase as well as a template for transcription. The structural elements of RNA directing the expression of RNA polymerase functions were analyzed using variant forms of the model RNA templates.
The object of this study was to investigate the effects of a b3 adrenergic receptor agonist (ARa) and estrogen on bone remodeling and bone marrow adipocyte differentiation. Ten-week-old female Sprague-Dawley rats underwent sham operation (Sham) or were ovariectomized (OVX) and were divided into four groups: Sham, Sham+ARa, OVX, and OVX+ARa groups. They were given orally the b3-ARa, BRL 35135, or vehicle daily for 4 weeks and their tibial and lumbar spinal bone and fat histomorphometric parameters were measured. In tibial proximal metaphysis, the adipocyte number per bone marrow unit volume (N.A/MV), and the percent adipocyte volume (AV/MV) values of the OVX and OVX+ARa groups were significantly higher than the Sham and Sham+ARa groups (P = 0.004, P = 0.008 in OVX, respectively), but ARa administration had no effect on bone remodeling or adipocyte differentiation. N.A/MV and AV/MV correlated negatively with the bone volume (BV/TV, r = -0.67, P = 0.001; r = -0.62, P = 0.004, respectively), and they correlated with the bone resorption parameters, i.e., the eroded surface (ES/BS), osteoclast surface (Oc.S/BS), and osteoclast number (N.Oc/BS) in tibial proximal metaphysis. In tibial distal metaphysis, the adipocyte volume per cell (AV/N.A) values of the OVX and OVX+ARa groups were significantly higher than those of the Sham and Sham+ ARa group (P = 0.003 in OVX). In the lumbar spine, the AV/N.A values of the Sham+ARa and OVX+ARa groups were significantly lower than the Sham and OVX groups values (P < 0.0001 in ARa administration), but OVX did not affect adipocyte differentiation. Beta3-ARa administration affects the bone marrow adipocyte differentiation, which is site-specific difference, although mainly negative in the context of bone.
A method for the analysis of the sialo-N-glycans in glycoproteins was established by the electrokinetic chromatography mode of capillary electrophoresis (CE) in sodium dodecyl sulfate (SDS) micelles as 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatives, using sialo-N-glycans in fetuin as a model. Six major and some minor peaks were observed for the N-glycans in fetuin, which were well separated from each other using 50 mM phosphate buffer, pH 6.0, containing SDS to a concentration of 30 mM in an uncoated fused-silica capillary, and these peaks were assigned to sialo-N-glycans having either of the biantennary or beta1-3/beta1-4 linked galactose-containing complex type triantennary N-glycans as the basic structures, by an indirect method based on the assignment of the peaks in high-performance liquid chromatography separated in parallel with CE and peak collation between these two separation methods. The attaching position of the sialic acid residue was determined using the linkage preference of neuraminidase isozymes. The established system is considered to be useful for routine analysis of microheterogeneity of the carbohydrate moiety of this model glycoprotein from the following reasons: (1) the derivatization with PMP proceeds quantitatively under mild conditions without causing release of the sialic acid residue, (2) the derivatives can be sensitively detected by UV absorption, (3) the procedure is simple, rapid and reproducible. Preliminary results of N-glycan analysis for several other glycoproteins under these conditions are also presented.