Biomedical subjects
Publications and source records attributed to K Goto.
The development of the floral organs is specified by the combinations of three classes of gene for organ identity in the 'ABC' model. Recently, molecular genetic studies have shown this model is applicable to grass plants as well as most eudicots. Transcription factor complexes of ABC and homologous proteins form the molecular basis of the ABC model.
We investigated the effects of a nuclear receptor system constituted by retinoid X receptor (RXR) and its heterodimer partner on the aromatase activity in a cultured MCF-7 human breast cancer cell line and also in human ovarian granulosa cells, using each selective ligand for retinoic acid receptor, RAR (TTNPB), retinoid X receptor, RXR (LG100268), PPARgamma (troglitazone), and vitamin D3 receptor (cholecalciferol). In MCF-7 cells, the combined treatment with TTNPB and LG100268 caused a dramatic stimulation of the aromatase activity. The combined treatment with other ligand and LG100268 had little or no effect on the aromatase activity. The increase in the aromatase activity by TTNPB plus LG100268 was accompanied by an increase in the P450arom mRNA levels, which was also found to be related to the specific usage of promoter 1a of the CYP19 gene. These results suggest that a nuclear receptor system constituted by a RAR:RXR heterodimer is involved in the regulation of aromatase activity in MCF-7 breast cancer cells. In cultured human ovarian granulosa cells obtained from patients who underwent in vitro fertilization, troglitazone or LG100268 alone decreased the aromatase activity, while the combined treatment caused an even greater reduction in this activity. Little effect of other specific ligands for RXR heterodimer partners may support the notion that the effects of troglitazone and/or LG100268 in human granulosa cells may be mediated through the specific activation of PPARgamma:RXR heterodimer system. Since similar manners of effects of several PPARgamma ligands and/or LG100268 on the aromatase activity were observed in a newly established human ovarian granulosa cancer cell line, KGN, we performed the detailed analysis of the mechanisms of these effects using this cell line. As a result, the inhibitory effect of aromatase activity by troglitazone plus LG100268 was accompanied by the decrease of P450arom mRNA level. Furthermore, the loss of P450arom expression was considered to be due to both the decreased transcription and rapid degradation of its RNA based on the studies of nuclear run-on assay and RNA stability assay. In conclusion, RAR:RXR and PPARgamma:RXR heterodimer nuclear receptor systems may be other important modulators of estrogen production in human breast cancer cells and ovarian granulosa cells, respectively.
The cell cycle of eukaryotes is tightly regulated through the activity of cyclin-dependent kinases. The Arabidopsis thaliana CDKA;1 (CDC2aAt) gene is thought to encode such a protein kinase, since it is actively transcribed in proliferating tissues and can complement defects in the Schizosaccharomyces pombe cdc2 gene. We analyzed the functional structure of the CDKA;1 promoter, using fusion genes between various upstream regions of CDKA;1 and the Escherichia coli beta-glucuronidase (GUS) gene. A 595 bp DNA fragment upstream from the transcription start site conferred GUS activity on developing trichomes, but not on proliferating tissues. On the other hand, another upstream fragment extending to the 5' non-coding transcribed region gave GUS activity to both proliferating tissues and developing trichomes. Against the gl2 mutant background, GUS activity directed by the 595 bp fragment was detected in single-stalk cells, but not in giant cells without obvious polar extension growth. These results revealed that the 595 bp fragment lacks cis element(s) essential for proliferating-cell-specific promoter activity, but can direct transcription in a specific period during trichome development, which does not include cell division. This suggests that CDKA;1 functions during cell morphogenesis as well as cell proliferation.
BACKGROUND: In lung protective strategy, positive end-expiratory pressure (PEEP) slightly higher than the Pflex (the airway pressure corresponding to the lower inflection point (LIP) on the inspiratory pressure-volume (P-V) curve measured with ZEEP) is generally recommended. However, this method to determine optimal PEEP lacks a theoretical background and there is no clinical report that investigated how the P-V relationship would be with such PEEP. Therefore, we measured inspiratory P-V curves at different PEEP levels to increase our knowledge about the inspiratory P-V curve with PEEP. METHODS: In eight consecutive patients with ALI/ARDS, inspiratory P-V curves were repeatedly measured at different PEEP levels by low flow inflation technique and LIP was assessed in all inspiratory P-V curves. Afterwards, the minimum PEEP level at which LIP was not identifiable (PEEP(LIP)(-)) was determined and the relationship between Pflex and PEEP(LIP)(-) was investigated. RESULTS: Pflex and PEEP(LIP)(-) could be determined in all patients. Pflex was 9.4+/-2.0 cmH2O (range: 7 to 12 cmH2O) and PEEP(LIP)(-) was 7.9+/-1.6 cmH2O (range: 5 to 10 cmH2O) (mean+/-SD, P=0.0877). PEEP(LIP)(-) was lower than the Pflex in five patients, and significantly lower than the Pflex + 2 cmH2O (P=0.0024). CONCLUSION: From the analysis of inspiratory P-V curves at different PEEP levels, PEEP 2 cmH2O higher than the Pflex may not be necessary to prevent cyclic collapse and reopening of alveoli, at least in some ALI/ARDS patients. Further studies are needed to confirm this preliminary result.
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.
Twelve cases of carcinoid tumors of the thymus were reviewed in terms of clinicopathologic, histochemical, and immunohistochemical features and DNA ploidy patterns. The collective consisted of nine male and three female patients, aged 34 to 74 years, of whom five (42%) had symptoms. Eleven patients underwent surgical resection, and one with systemic metastases was autopsied. In the 11 resected patients, tumors had invaded surrounding structures in four cases, and mediastinal lymph node metastases were detected in six. Recurrence occurred in two of the resected patients (18%), and the 5-year survival rate was 82%. Histologically, all tumors showed an organoid growth pattern with delicate fibrovascular stroma. In addition, three tumors had unusual morphologic features such as combined features of carcinoid tumor and thymoma and solid growth pattern with occasional large tumor cells. Mitotic counts ranged from 1 to 14 per 10 high-power fields with a mean count of 4.9. Central necrosis within solid nests was observed in nine tumors. Classification of this series using the WHO histologic classification system resulted in categorization of all 12 tumors as atypical carcinoids. All tumors were positive for Grimelius staining and for cytokeratin. Immunohistochemical staining documented the presence of moderately to strongly positive neuroendocrine markers such as neuron-specific enolase, chromogranin A, synaptophysin, and neural cell adhesion molecule. No correlation between proliferative activity based on the Ki67 labeling index and prognosis or lymph node metastasis was found. Concerning DNA ploidy patterns, only one tumor with multiple lymph node metastases was considered to be aneuploid. In conclusion, although all of our cases were histologically classified as atypical carcinoid tumors of the thymus, most were diploid, and the patients enjoyed a relatively good prognosis.
To evaluate the correlation between the degree of basement membrane (BM) preservation and clinicopathological characteristics in the replacement-growth type (lepidic growth type) of small peripheral adenocarcinomas of the lung, the BM components of 72 surgically resected replacement-growth type adenocarcinomas of the lung, 2 cm or less in diameter, were evaluated immunohistochemically by using a monoclonal antibody to Type IV collagen and polyclonal antibodies to 7S collagen and laminin. The tumors were classified into the following three distinctive histological types according to the condition of the elastic framework: Type I, bronchioloalveolar carcinoma without fibrotic foci; Type II, sclerosing bronchioloalveolar carcinoma without elastic framework destruction; and Type III, sclerosing bronchioloalveolar carcinoma with elastic framework destruction. The BM was well preserved in the area of bronchioloalveolar spread along fully expanded alveoli in all tumor types; however, BM preservation was significantly lost in the areas of collapsed alveoli in Type III tumors. There were no BM component staining reactions in the scarred regions of Type III tumors. In addition, lymph node metastasis was significantly greater in Type III tumors and BM-destroyed tumors. We concluded that the BM was largely destroyed by tumor cell invasion in the scarred region of Type III adenocarcinomas. Type III tumors had discontinuous BMs in the area of collapsed alveoli, indicating that this BM-destructive pattern must be the first step in tumor invasion. Type I and II tumors were concluded to be noninvasive adenocarcinomas, because their BM components were well preserved and they had a good outcome.
BACKGROUND: The TERMINAL FLOWER 1 (TFL1) gene of Arabidopsis plays an important role in regulating flowering time and in maintaining the fate of inflorescence meristem (IM). TFL1 is a homologue of CENTRORADIALIS (CEN) from Antirrhinum, which is only involved in IM maintenance. Recent mutational studies and the genome project revealed that TFL1 belongs to a small gene family in Arabidopsis, in which functional divergence may have occurred among the members. RESULTS: We found a new member of the TFL1 gene family, which is mapped on chromosome 2 of Arabidopsis. The predicted protein sequence encoded by this gene is more closely related to that of CEN than other Arabidopsis TFL1 homologues (and therefore named ATC for Arabidopsis thaliana CENTRORADIALIS homologue). Transgenic plants constitutively expressing the ATC gene (35S:ATC), in either wild-type or tfl1 mutant backgrounds, showed a phenotype similar to that observed in transgenic plants constitutively expressing the TFL1 gene. However, in contrast to TFL1, the expression of ATC was only detected in the hypocotyl of young plants, and not in the IM. In addition, an atc loss-of-function mutant, isolated by screening a T-DNA library, showed no phenotypes that were similar to those of tfl1 mutants. CONCLUSION: The phenotypes of transgenic plants over-expressing ATC suggest that the ATC protein can functionally substitute for TFL1. However, the pattern and level of expression and the loss-of-function phenotype indicate that ATC does not participate in the regulation of IM identity, but rather has a role that is different from that of TFL1.
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BACKGROUND: To determine the maximum tolerated dose and recommended dose of cisplatin and docetaxel administered by three consecutive weekly infusions in both non-elderly (< or =74 years) and elderly (> or =75 years) patients, we conducted two independent phase I studies for nonelderly and elderly patients with non-small cell lung cancer. METHODS: Between April 1998 and September 1999, 26 non-elderly (median, 54 years; range, 44-73 years) and 12 elderly (median, 76 years; range, 75-80 years) patients with non-small cell lung cancer were entered in these studies. The eligibility criteria of both cohorts were identical except for age. Chemotherapy consisted of cisplatin 25 mg/m2 and an escalated dose of docetaxel on days 1, 8 and 15 every 4 weeks. The initial dose of docetaxel was 20 mg/m2 and it was increased by 5 mg/m2 at each dose level. RESULTS: In the non-elderly and elderly cohorts, up to 45 or 25 mg/m2 of docetaxel, respectively, were administered. Dose-limiting toxicities were neutropenia, liver damage, pneumonia and omission of treatment on day 15 by leukopenia and refusal in the non-elderly cohort; pneumonia and omission of treatment on day 15 by refusal due to fatigue/asthenia or fever in the elderly cohort. We considered the recommended doses for phase II studies were cisplatin 25 mg/m2 and docetaxel 35 mg/m2 on days 1, 8 and 15 for non-elderly patients and cisplatin 25 mg/m2 and docetaxel 20 mg/m2 on days 1, 8 and 15 for elderly patients. Seven of 26 (27%) and seven of 12 (58%) patients achieved a partial response, median survival times were 8.7 and 7.2 months and 1 year survival rates were 27 and 27% in the non-elderly and elderly cohorts, respectively. CONCLUSIONS: Further evaluation of this combination chemotherapy is warranted for both nonelderly and elderly patients with non-small cell lung cancer but the dose of docetaxel should be lower for elderly than non-elderly patients.
BACKGROUND: Dehydrofluorination of sevoflurane by carbon dioxide absorbents in anesthesia machines produces compound A, which is nephrotoxic in rats. Several clinical studies indicate that prolonged low-flow sevoflurane anesthesia is associated with an increased urinary excretion of biochemical markers, such as protein. Probenecid, a competitive inhibitor of organic anion transport, diminishes compound A nephrotoxicity in rats. The purpose of the present study was to examine the effects of low- and high-flow sevoflurane anesthesia on urinary excretion of biochemical markers in humans and to examine the effects of probenecid on urinary excretion of these markers. METHODS: Elective surgical patients (n = 64) were assigned to four groups (n = 16 each): low-flow sevoflurane plus probenecid (LSP), low-flow sevoflurane (LS), high-flow sevoflurane plus probenecid (HSP), and high-flow sevoflurane (HS). Probenecid (2.0 g) was administered orally 2 h before the induction of anesthesia in both the LSP and HSP groups. Nothing was administered orally 2 h before the induction of anesthesia in either the LS or HS groups. All patients underwent prolonged low-flow (1 l/min) or high-flow (6 l/min) sevoflurane anesthesia. Urinary excretion of protein, albumin, beta(2)-microglobulin, glucose, and N-acetyl-beta-d-glucosaminidase was measured for up to 7 days postoperatively. RESULTS: Sevoflurane doses were similar in all four groups. There were no differences in blood urea nitrogen, creatinine, or creatinine clearance among the four groups after anesthesia. Average values for urinary excretion of protein, beta(2)-microglobulin, and N-acetyl-beta-d-glucosaminidase in the LS group were significantly higher than those in the other groups (LSP, HSP, HS; P < 0.05). There was no significant difference between the LS and LSP groups in average values for urinary excretion of albumin and glucose, although there were significant differences between the LS and both high-flow sevoflurane groups (HSP, HS). CONCLUSIONS: Low-flow sevoflurane, which produces a sevenfold higher compound A exposure than high-flow sevoflurane, resulted in significant increases of several biochemical markers in half of the patients. Probenecid appears to provide protection against these renal effects.
We report the case of a 34-year-old woman with a solid cystic tumor (SCT) of the pancreas accompanied by ossification and possible malignancy, coexisting nonfusion of the pancreatic ducts. There was a 24 x 29 x 33-mm mass with a prominent calcified lesion in the tail of the pancreas detected by abdominal ultrasonography, computed tomography, and magnetic resonance imaging. There were no distal metastases detected. Endoscopic retrograde pancreatography revealed nonfusion of the pancreatic ducts. The resected tumor consisted of solid and cystic components. The tumor was not encapsulated and included a severely ossified lesion inside. On microscopy, the tumor cells were small, eosinophilic, and proliferated in a solid or pseudo-papillary pattern. The tumor cells infiltrated into the surrounding normal pancreas parenchyma and invaded part of the mesentery. The immunostaining was positive for alpha-1-antitrypsin, neuron-specific enolase, vimentin, and chromogranin A. In the literature, only a few cases of SCT of the pancreas described ossification. As far as we know, only three cases of SCT of the pancreas, which demonstrated nonfusion of the pancreatic ducts, have been reported. Thus, SCT of the pancreas with ossification, possible malignancy, and coexisting nonfusion of the pancreatic ducts is extremely rare.
In chronic heart failure and acute myocardial infarction, the tissue level of endothelin (ET)-1 in the heart, as well as its plasma level, has been reported to increase markedly. There is, however, little information about what in these pathologic conditions leads to increased production of ET-1, and which type of cell in the heart produces ET-1. We examined the mRNA and peptide expression of ET-1 using cultured rat neonatal cardiomyocytes, in which mitochondrial dysfunction was induced by rotenone, a mitochondrial respiratory chain complex I inhibitor, because one of the common features in failing or ischemic hearts is an alteration in energy metabolism due to mitochondrial dysfunction. Rotenone increased glucose use by the culture cells within 12 h of addition without affecting cell viability, and depressed the mitochondrial membrane potential after 72 h, indicating the induction of mitochondrial dysfunction in cardiomyocytes. Rotenone induced significant increase in the expression level of mRNA for ET-1 within 1 h of addition. In accordance with this finding, immunoreactive ET-1 in culture medium increased 3 times after 24 h of incubation, suggesting active secretion of ET-1 from cultured cells treated with rotenone. Immunocytochemical analysis verified significant increase of ET-1 peptide in cardiomyocytes, confirming the production of ET-1 by cardiomyocytes. These results suggest that derangement of mitochondrial function in cardiomyocytes itself could lead to the increased production of ET-1 in cardiomyocytes, and that this mechanism may contribute to the increased production of ET-1 in failing and ischemic hearts.
A novel power supply for medical implants has been developed. A wireless near-infrared power transmission recharges a lithium secondary battery in the power supply. A photovoltaic cell array embedded under skin receives near-infrared light through the skin and charges the battery directly powering an implanted device. We have shown that, for a photodiode area of 2.1 cm2, 17 min of near-infrared irradiation at a 810-nm wavelength with a power density of 22 mW/cm2 can send enough energy to allow regular commercial cardiac pacemakers to run for 24 h. The temperature rise of the skin during the light irradiation was 1.4 degrees C.
A cell extract of an extremely thermophilic bacterium, Thermus thermophilus HB8, cultured in a synthetic medium catalyzed cystathionine gamma-synthesis with O-acetyl-L-homoserine and L-cysteine as substrates but not beta-synthesis with DL-homocysteine and L-serine (or O-acetyl-L-serine). The amounts of synthesized enzymes metabolizing sulfur-containing amino acids were estimated by determining their catalytic activities in cell extracts. The syntheses of cystathionine beta-lyase (EC 4.4.1.8) and O-acetyl-L-serine sulfhydrylase (EC 4.2.99.8) were markedly repressed by L-methionine supplemented to the medium. L-Cysteine and glutathione, both at 0.5 mM, added to the medium as the sole sulfur source repressed the synthesis of O-acetylserine sulfhydrylase by 55 and 73%, respectively, confirming that this enzyme functions as a cysteine synthase. Methionine employed at 1 to 5 mM in the same way derepressed the synthesis of O-acetylserine sulfhydrylase 2.1- to 2.5-fold. A method for assaying a low concentration of sulfide (0.01 to 0.05 mM) liberated from homocysteine by determining cysteine synthesized with it in the presence of excess amounts of O-acetylserine and a purified preparation of the sulfhydrylase was established. The extract of cells catalyzed the homocysteine gamma-lyase reaction, with a specific activity of 5 to 7 nmol/min/mg of protein, but not the methionine gamma-lyase reaction. These results suggested that cysteine was also synthesized under the conditions employed by the catalysis of O-acetylserine sulfhydrylase using sulfur of homocysteine derived from methionine. Methionine inhibited O-acetylserine sulfhydrylase markedly. The effects of sulfur sources added to the medium on the synthesis of O-acetylhomoserine sulfhydrylase and the inhibition of the enzyme activity by methionine were mostly understood by assuming that the organism has two proteins having O-acetylhomoserine sulfhydrylase activity, one of which is cystathionine gamma-synthase. Although it has been reported that homocysteine is directly synthesized in T. thermophilus HB27 by the catalysis of O-acetylhomoserine sulfhydrylase on the basis of genetic studies (T. Kosuge, D. Gao, and T. Hoshino, J. Biosci. Bioeng. 90:271-279, 2000), the results obtained in this study for the behaviors of related enzymes indicate that sulfur is first incorporated into cysteine and then transferred to homocysteine via cystathionine in T. thermophilus HB8.
Helicobacter hepaticus contaminating nonfrozen tumors was transmissible to severe combined immunodeficient (SCID) mice, but the organism in cryopreserved samples was not. This suggests that H. hepaticus has the ability to spread via biomaterials and that freezing-thawing is able to reduce the numbers of organisms to levels insufficient for subcutaneous infection of SCID mice.
Stimulation of beta-adrenoceptors leads to vascular smooth muscle hyperpolarization, presumably through the beta-adrenoceptors/Gs protein/adenylate cyclase/ATP-sensitive K(+)-channels (KATP) signaling cascade, which may play an important role in the sympathetic control of membrane potential. beta-Adrenoceptor-mediated hyperpolarization has been shown to be impaired in the established stage of experimental hypertension. The present study tested the hypothesis that beta-adrenergic hyperpolarization may be defective before the development of hypertension in some forms of genetic hypertension. We evaluated beta-adrenoceptor-mediated hyperpolarization using microelectrodes in mesenteric resistance arteries from 5-week-old, prehypertensive, spontaneously hypertensive rats (SHR) and age-matched Wistar-Kyoto rats (WKY). Isoproterenol-induced hyperpolarization was significantly smaller in SHR than in WKY (10(-7) mol/L: -4.6+/-0.6 versus -7.8+/-0.8 mV, P<0.01; 10(-6) mol/L -7.8+/-0.5 versus -9.8+/-0.6 mV, P<0.05; n=9). Furthermore, hyperpolarization to cholera toxin, a direct activator of Gs protein, was also impaired in SHR. On the other hand, hyperpolarization to forskolin, an adenylate cyclase activator, and to levcromakalim, a KATP opener, was comparable between groups. These findings suggest that beta-adrenoceptor-mediated hyperpolarization is defective in SHR before the development of hypertension, presumably because of an abnormality at the Gs protein site. Considering the importance of membrane potential in the control of vascular tone, altered beta-adrenergic control of membrane potential might play a role in the development of hypertension in SHR.
We established a steroidogenic human ovarian granulosa-like tumor cell line, designated KGN, from a patient with invasive ovarian granulosa cell carcinoma. KGN had a relatively long population doubling time of about 46.4 h and had an abnormal karyotype of 45,XX, 7q-, -22. A steroid analysis of the cultured medium by RIA performed 5 yr after the initiation of culture showed that KGN was able to secrete pregnenolone and progesterone, and both dramatically increased after stimulation with (Bu)(2)cAMP. However, little or no secretion of 17alpha-hydroxylated steroids, dehydroepiandrosterone, androstenedione, or estradiol was observed. The aromatase activity of KGN was relatively high and was further stimulated by (Bu)(2)cAMP or FSH. These findings showed a pattern similar to that of steroidogenesis in human granulosa cells, thus allowing analysis of naturally occurring steroidogenesis in human granulosa cells. Fas-mediated apoptosis of KGN was also observed, which mimicked the physiological regulation of apoptosis in normal human granulosa cells. Based on these findings, this cell line is considered to be a very useful model for understanding the regulation of steroidogenesis, cell growth, and apoptosis in human granulosa cells.