An in vitro transcription system from BmN cells of the silkworm, Bombyx mori.
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Adenosine Triphosphate↗
Biomedical subjects
H Sakurai
Publications and source records attributed to H Sakurai.
No-effect level of subacute tetraethoxysilane inhalation on the mouse kidney.
To determine safe exposure levels of tetraethoxysilane (TEOS) in the kidney, groups of male ICR mice (SPF grade) containing 10 animals each were exposed to TEOS, 100 ppm or 50 ppm, for 6 hours/day, 5 days/week, for 2 or 4 weeks. Tubulo-interstitial nephritis developed in mice exposed to 100 ppm for 2 and 4 weeks, but no kidney lesions or renal function changes were observed in mice exposed to 50 ppm. However, histopathological changes were detected in the nasal mucosa of mice exposed to 50 ppm TEOS. These results indicate that the occupational exposure level for TEOS should be strictly maintained below the current recommended exposure limit, 10 ppm, set by many countries and academic associations, and that renal tubular function of TEOS-exposed workers should be assessed and monitored for a long period.
Administration, Inhalation↗
No-observed-effect level of diborane on the respiratory organs of male mice in acute and subacute inhalation experiments.
In order to clarify the acute and subacute toxicity of diborane (B2H6, CAS: 19287-45-7) at low concentrations, male ICR mice were exposed to diborane for 1, 2, 4 or 8 h at concentrations of 1 or 5 ppm (phase I study), and for 6 h/day, 5 days/wk, over 2 or 4 wk at concentrations of 0.02 or 0.7 ppm (phase II study). Hematological and biochemical tests, and histopathological examinations of the cornea, nasal mucosa, respiratory tract and lung were carried out. All mice in both studies survived until they were sacrificed. In the phase I study, lung weight increased significantly in mice exposed to 5 ppm of diborane for 8 h. Histopathologically diffuse panbronchiolitis-like lesion was observed in mice exposed to 5 ppm of diborane for 2, 4 or 8 h. In the phase II study, slight infiltration of polymorphous neutrophil was observed mainly in the peribronchiolar region in mice exposed to 0.2 ppm or 0.7 ppm of diborane for 2 or 4 wk. In both studies, hematological and biochemical examinations failed to reveal any exposure-related changes. These results suggest that no-observed-effect level of diborane inhalation on the respiratory organs were 1 ppm in acute exposure, but 0.2 ppm of diborane inhalation for 2 or 4 wk seems to be unsafe.
Acute Disease↗
A new nitric oxide (NO) releaser: spontaneous NO release from FK409.
The remarkable vasorelaxant and anti-platelet effects of FK409 have been reported to be due to nitric oxide (NO) release. The purpose of the present study is to investigate the spontaneous NO-releasing pathway of FK409 in aqueous solutions. 1H-NMR spectra of FK409 suggested that the compound underwent a time-dependent elimination of the hydrogen atom at alpha-position of the nitro moiety (at the 5-position) in weakly alkaline solutions. In addition, the degradation of FK409 monitored by HPLC showed a pH-dependency accelerating with an increase of pH. These results revealed that the first step in the degradation of FK409 might be the hydroxyl ion-dependent subtraction of the hydrogen atom at the 5-position. On the other hand, NO release from FK409 also exhibited a pH-dependency, and the velocity of NO liberation was markedly enhanced above pH 6. Furthermore, a linear relationship between the rate of FK409 degradation and that of NO formation was observed, indicating that the rate-limiting step for NO formation is the same as that for degradation. Thus, the rate-limiting process of NO formation from FK409 is due to the deprotonation reaction of the hydrogen atom at the 5-position by hydroxyl ions. The deprotonation process appears to be an essential step for both FK409 degradation and NO release. On the basis of the results, a possible kinetic scheme for NO release from FK409 is proposed.
Buffers↗
Peroxyl radical scavenging activities of hamamelitannin in chemical and biological systems.
The antioxidative activities of hamamelitannin (2',5-di-O-galloyl-hamamelose), gallic acid and dl-alpha-tocopherol against lipid peroxyl radicals were evaluated in chemical and biological systems. The peroxyl radical scavenging activity was evaluated by electron spin resonance (ESR) method in which both spin-trapping and direct reaction methods were used. In the spin-trapping method, as evaluated by 50% inhibition concentration (IC50) of peroxyl radicals generated in a t-butylhydroperoxide-methemoglobin system, hamamelitannin (IC50 = 95.3 +/- 2.7 microM) showed the highest activity, followed by gallic acid (IC50 = 152.8 +/- 14.6 microM) and dl-alpha-tocopherol (IC50 = 221.5 +/- 4.6 microM) as a positive control. When estimating by the direct method, IC50 values of hamamelitannin, gallic acid and dl-alpha-tocopherol were 93.5 +/- 2.1 microM, 141.6 +/- 2.0 microM and 1590.0 +/- 330.0 microM, respectively. On peroxidation of lipid bilayers induced by 2,2'-azobis-(2-amidinopropane) dihydrochloride (AAPH) in terms of inhibition period (tinh), hamamelitannin showed the longest tinh time (1107.0 +/- 38.18 sec), followed by those of dl-alpha-tocopherol (877.5 +/- 31.8 sec) and gallic acid (771.0 +/- 4.2 sec). The kinetic chain length, defined as the propagation numbers of a lipid peroxyl radical, and calculated from the ratio (Rp/Ri) of the rate of lipid peroxidation to that of inhibition by dl-alpha-tocopherol, hamamelitannin and gallic acid were 27.23, 7.86 and 7.09, respectively. The effects of hamamelitannin, gallic acid and dl-alpha-tocopherol were evaluated on murine fibroblasts exposed to t-butylhydroperoxide (BHP) in terms of the cell survivals. In the protection, hamamelitannin induced the highest survival of 27.6 +/- 0.6% at 50 microM, while both gallic acid and dl-alpha-tocopherol were less active at the same concentrations. On the basis of the results, hamamelitannin was concluded to have a high protective activity on cell damage induced by peroxides.
Animals↗
[Secondary tumor of the temporal bone with internal auditory meatus involvement--histopathological study].
Nineteen cases of secondary tumor of the temporal bone with involvement of the internal auditory meatus (IAM) were studied. The cases were classified into 4 invasion modes; direct extension from head and neck tumors (12 cases), hematological dissemination (3 cases), diffuse leptomeningeal carcinomatosis (3 cases), and direct extension of tumors from the intracranium (1 case). There were some differences in the manner in which the tumor had spread among these 4 modes. In most cases involving "direct extension from head and neck tumors", the tumor had invaded the pyramis, and then the Eustachian tube and the middle ear. When the inner ear or the IAM was involved, it was directly invaded by massive tumor. In all cases of "hematological dissemination", metastatic tumor was found bilaterally, but there were some differences in the manner of invasion between the two sides. In "leptomeningeal carcinomatosis" and "intracranial tumor", the tumor had invaded the temporal bone bilaterally via the IAM. In the IAM, cochlear and inferior vestibular nerves were more vulnerable to tumor invasion than facial and superior vestibular nerves. It was suggested that there are some differences in vulnerability to tumor invasion between the superior and inferior vestibular nerves. The bottom of the IAM presented a barrier-like effect against the spread of tumor from the IAM to the labyrinth. In some cases, however, there was massive tumor invasion of the internal ear directly from the IAM. Whether denervation of the ganglionic neurons (spiral or vestibular) causes secondary degeneration of peripheral sensory endorgans remains controversial. In some cases in our series, degeneration of the auditory or vestibular peripheral organs might be attributed to denervation of neurons in the spiral or vestibular ganglia. In other cases, however, auditory and vestibular peripheral organs remained intact despite severe degeneration of ganglionic neurons.
Adolescent↗
[Neurilemmoma of intra-temporal facial nerve:case report].
A case of facial nerve neurilemmoma within the temporal bone is reported. The patient is a 47-year-old female complaining of 10 years' history of left facial palsy. CT and MRI examinations showed an enlarged mass of the tympanic cavity protruding into the petrous bone, mastoid cavity and external auditory meatus. An open biopsy of the tumor at the external auditory meatus revealed neurilemmoma. The tumor was totally removed by a retroauricular approach. Five months after surgery, both the cross nerve graft using the peroneal nerve and the temporal muscle transfer, method modified by Johnson were performed for the functional recovery of facial palsy.
Cranial Nerve Neoplasms↗
Prognostic factors for loco-regional control and outcome of re-irradiation for patients with poorly-differentiated squamous cell carcinoma of the nasopharynx.
Retrospective analysis was performed to evaluate the prognostic factors for loco-regional control and the results of re-irradiation for 28 patients with recurrent, poorly-differentiated squamous cell carcinoma (PDSCC) of the nasopharynx. Twenty-four of them received re-irradiation. Local, local plus regional and regional recurrences were observed in 19, five and four patients, respectively. Except for three patients, all had Stage IV disease at the initial diagnosis. The only parameters influencing loco-regional recurrence were T and N stage categories. The median latent period from initial treatment to recurrence was 18.5 (range, 2-100) months. There was no difference in latent period by first recurrence site, although recurrent tumors confined to the nasopharynx or those only regionally developed had a longer latent period. Only four patients developed secondary distant bone metastases with a median latency of three months from loco-regional relapse. The patients with local recurrent tumors confined to the nasopharynx, and those with regional recurrences only, could be salvaged by re-irradiation, with five-year survival rates of 44 and 100%, respectively. Five of 28 patients (18%) developed severe chronic radiation sequelae: cerebrospinal complications in four patients, bilateral neck fibrosis in one. We conclude that recurrent PDSCC of the nasopharynx can be controlled by re-irradiation with some success. Radiation therapy techniques must, however, be carefully planned in order to avoid the severe late post re-irradiation sequelae. For patients with advanced non-curable local recurrences, palliative care should be recommended instead of agressive re-irradiation.
Carcinoma, Squamous Cell↗
[Immunohistochemical study of radiation-induced apoptosis and oncogenes].
Relationships between radiation-induced apoptosis and oncogenes or suppressor genes (p53, MDM2, c-myc, p21ras and bcl-2) were immunohistochemically studied in 7 human tumors transplanted to nude mice. The most radiosensitive ependymoblastoma was negative for p53 and c-myc, however, the other 6 tumors were positive for them. Following irradiation, the ependymoblastoma became p53 positive, and showed the highest incidence of apoptosis among the 7 tumors. In addition, bcl-2 expression in this tumor was slightly different from that in the others.
Animals↗
Yeast GAL11 protein stimulates basal transcription in a gene-specific manner by a mechanism distinct from that by DNA-bound activators.
The GAL11 gene encodes an auxiliary transcription factor required for full expression of many, if not all, genes of the yeast Saccharomyces cerevisiae. We have recently shown that GAL11-encoded protein (Gal11p) enhances basal transcription from the CYC1 promoter in a cell-free transcription system [(1993) Proc. Natl. Acad. Sci. USA 90, 8382-8386]. Here we indicate that Gal11p stimulates basal transcription in a gene-specific manner in vitro. We further suggest that the mechanism underlying the transcriptional stimulation by Gal11p is distinct from that by DNA-bound activators, since Gal11p stimulated transcription in a reaction system where activators were unable to enhance transcription due to the lack of intermediary factors.
Cell-Free System↗
Evaluation of external beam therapy and three brachytherapy fractions for carcinoma of the uterine cervix.
PURPOSE: A retrospective analysis was performed to evaluate external beam therapy and three brachytherapy fractions for patients with squamous cell carcinoma of the uterine cervix, compared with those with other histological types. METHODS AND MATERIALS: Three hundred and twenty-two patients with carcinoma of the uterine cervix received external pelvic irradiation combined with three sessions of low dose rate intracavitary irradiation within 6 weeks. Two hundred and ninety-three patients had squamous cell carcinoma (SCC), whereas 29 patients had nonsquamous cell histology (N-SCC): 18 had adenocarcinoma, 5 had undifferentiated carcinoma, 4 had adenosquamous carcinoma, and 2 had adenoacanthoma. Survival rates, patterns of failure, local control rates, and complications in the patients with SCC were compared with those in the patients with N-SCC. RESULTS: The 5-year overall actuarial survival rates for the patients with SCC and for those with N-SCC were: 84% and 100% in Stage I disease, 72% and 38% in Stage II disease, 52% and 17% in Stage III disease, and 29% and 0% in Stage IV disease, respectively. The 5-year cause specific survival rates for the patients with SCC in Stages I to IV disease were 100%, 87%, 72%, and 39%. Corresponding rates for the patients with N-SCC were 100%, 43%, 25%, and 0%. There was a statistically significant difference between the survival curves for two histological types in Stage II B, III B, and IV A diseases. The local control for the patients with N-SCC was worse than in the patients with SCC. The crude moderate and severe rectal complication rates (Grades 3 and 4) for the patients with SCC and for the patients with N-SCC were 7.5% and 3.4%, respectively. Only one patient with SCC developed chronic small intestinal injury in this series. We observed four patients with SCC who developed Grade 2 and four with Grade 4 urinary bladder complications. CONCLUSIONS: Three sessions of intracavitary brachytherapy were a safe and effective procedure for the patients with SCC and the outcome of radiation therapy in the patients with SCC was satisfactory even in advanced cases. However, local control of N-SCC is difficult to achieve by this method and the prognosis for patients with N-SCC was significantly worse than that for patients with SCC.
Adenocarcinoma↗
Site-specific DNA cleavage by Cu(II) complexes of podophyllotoxin derivatives.
Site-specific DNA cleavage in the presence of Cu(II) complexes of podophyllotoxin derivatives was investigated with a modified Sanger sequencing method. Cu(II) complexes of 4'-demethylepipodophyllotoxin (DEPD) and syringic acid (SA) cleaved M13mp18 single-strand DNA site-specifically at both cytosine (C) and guanine (G) positions in the GC rich regions and C position, respectively, at pH 7.8. The apparent binding constants of calf thymus DNA-Cu(II) complexes estimated by the differential UV-absorption spectra revealed that both Cu(II)-VP-16 and -DEPD complexes bind to DNA more strongly than does the Cu(II)-SA complex.
Base Sequence↗
A new orally active insulin-mimetic vanadyl complex: bis(pyrrolidine-N-carbodithioato)oxovanadium (IV).
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Adipocytes↗
High-performance liquid chromatographic analysis of methylation changes of CCGG sequence in brain and liver DNA of mice during pre- and postnatal development.
The change of the methylation of CpG in the CCGG sequence of brain and liver DNAs of mice during late fetal and suckling periods was determined by high-performance liquid chromatography using a reversed-phase column and 0.1 M phosphate buffer (pH 6.0) as the mobile phase. The tissue DNA was digested with the restriction enzyme, MspI, and was labeled at the 5'-end with [gamma-32P]ATP. The cpm% of deoxycytidine 5'-monophosphate (5mdCMP) in total CpG dinucleotides was calculated from the equation 5mdCMP/total CCGG (cpm%) = (5mdCMP)MspI,cpm/[(5mdCMP)MspI,cpm + (dCMP)MspI,cpm] x 100. The brain DNA exhibited a significant decrease in CpG methylation at prenatal day 18 but little change after birth. This marked decline of 5mdCMP in the CCGG sequence may be associated with the increase of enzymes before birth. The liver DNA showed considerable change during the late prenatal period. The observed changes of CpG methylation in liver DNA are indicative of the corresponding alterations of enzymes, multinucleate cells and hepatocytes. The results obtained indicate that both brain and liver cells have the development-associated changes in the conformation and transition of DNA around the time of birth.
Aging↗
Unusual generation of hydroxyl radicals in hepatic copper-metallothionein of LEC (Long-Evans cinnamon) rats in the presence of hydrogen peroxide.
A mutant strain of LEC rats (Long-Evans rats with a cinnamon-like coat color) develop spontaneous hepatic injury associated with severe jaundice about 4 months after birth. Recently, we obtained evidence which shows an unusual accumulation of copper (Cu) in the liver of LEC rats, followed by the finding of copper-metallothionein (Cu-MT) induction. To know the mechanism for the development of hepatitis in LEC rats, in relation to induced Cu-MT, we examined whether the generation of active oxygen species is observed. When the Cu-MT was treated with H2O2, which is formed by dismutation of superoxide anion radicals or NADPH oxidases in living systems, strong ESR signals due to Cu(II) state appeared when measured at 77K. On the same system, ESR signals due to the spin trapped hydroxyl radicals were observed at room temperature when DMPO (5,5-dimethyl-pyrroline-1-oxide) was used as a spin-trapping agent. The present results suggested that Cu-MT of LEC rat has an important pathogenic role by generating hydroxyl radicals, when hydrogen peroxide is produced in cells or tissues.
Animals↗
Purification of yeast histones competent for nucleosome assembly in vitro.
We have developed a procedure to purify nucleosomal assembly-competent histones as a mixture of H2A, H2B, H3 and H4 from isolated nuclei of the yeast Saccharomyces cerevisiae with a purity of 70-80%. The mixture contained each of the histone subunits approximately at the equi-molar ratio. Plasmid pBR322 DNA was assembled into nucleosomes with the purified yeast histones in the presence of nucleoplasmin from unfertilized eggs of the frog Xenopus laevis. The efficiency of assembly of yeast histones was comparable to that of core histones purified from HeLa cells. The length of DNA fragment wrapping around a core histone particle and the molar ratio of histone components in an assembled nucleosome particle were estimated to be 150 +/- 10 bp long and H2A:H2B:H3:H4 = 1.0:0.9:0:9:1.0, respectively.
Cell Nucleus↗
Surgical treatment of hepatocellular carcinoma.
The effect of surgical treatment for hepatocellular carcinoma (HCC) was evaluated in 149 resected cases, 83.2% of which were associated with liver cirrhosis. The 3- and 5-year survival rates were 60.1% and 39.4%, respectively. The mortality rate was 4.1%. In patients aged over 70 years, liver cirrhosis was found in 53.3% of cases and the mortality rate was 6.7%. The 3- and 5-year survival rates were 50.8% and 33.9%, respectively. Factors that significantly affected survival for more than 5 years were a tumor size of less than 3 cm, Stage I disease, vp(-), IMo, and diploid type. The 5-year survival rate for patients with a single tumor of 3 cm or less was 54.2%, regardless of the surgical procedure. All 15 patients with a solitary tumor of 2 cm or less (Stage I, small liver tumor) were alive with a 5-year survival rate of 100%. The problem is the treatment of patients with a tumor measuring 3-5 cm in diameter and associated liver cirrhosis, because their prognosis after surgery is the worst. HrS (subsegmentectomy) is the minimal procedure of limited hepatectomy for these cases with postoperative multidisciplinary therapy.
Adult↗
Acute and subchronic inhalation toxicity of tetraethoxysilane (TEOS) in mice.
To clarify the acute and subchronic inhalation toxicity of tetraethoxysilane [TEOS, Si(OC2H5)4], groups of ten male ICR mice (SPF grade) were exposed to 1000 ppm TEOS for 1,2,4 or 8 h (acute inhalation study), or to 200 ppm of TEOS for 6 h/day, 5 days/week, for 2 or 4 weeks (subchronic inhalation study). The numbers of mice that died during 2 weeks of observation were 0, 1, 1 and 6 in the 1-, 2-, 4- and 8-h inhalation experiments and zero in the subchronic inhalation study. In the acute inhalation study, body weight decreased after TEOS exposure and did not reach the level of control mice during 2 weeks of observation except in the 1-h inhalation study. In the subchronic exposure study, weight gain was suppressed during the exposure period. Body weight in mice exposed for 2 weeks reached the level of non-exposed mice during the 2-week observation period, but did not do so in mice exposed for 4 weeks. Acute tubular necrosis (ATN) and acute splenic atrophy (ASA) were observed in all dead mice in the acute inhalation study, and tubulointerstitial nephritis (TIN) was frequently found in the surviving mice in both the acute and subchronic studies. However, blood biochemical examinations revealed no evidence of renal dysfunction. The olfactory epithelium was necrotic in all dead mice. In the subchronic inhalation study, infiltration of polymorphonuclear neutrophils in the nasal mucosa was observed in all mice killed 1 day after exposure. These results indicate that the LCL0 for 1-h exposure to TEOS and LC50 for 4-h exposure are greater than 1000 ppm, and that the kidney and nasal mucosa are the target organs for TEOS inhalation.
Administration, Inhalation↗