Biomedical subjects

H Sakurai

Publications and source records attributed to H Sakurai.

At least 271 records · Page 15Linked to original sources

PubMed1997

Analysis of water sorption behavior of native and denatured proteins by solution thermodynamics.

Water sorption isotherms of native and denatured ovalbumin samples were measured, and their affinity for water was quantitatively analyzed by solution thermodynamics. The structural change of the proteins was evaluated by several methods. Water activity above 0.9 was measured by adding a specific amount of water to a sample, while that elbow 0.9 was measured with apparatus for water sorption isotherms. Thus, water sorption isotherms for native and denatured ovalbumin samples were obtained up to a water activity of 0.99. The water sorption behavior of ovalbumin was affected not by its hydrophobicity but by its prominent conformational change. It was confirmed that parameter delta Gs calculated by solution thermodynamics was more suitable for evaluating the affinity for water from water sorption isotherms than delta Gws calculated by conventional adsorption thermodynamics.

Adsorption↗

PubMed1997

Molecular cloning of an inulin fructotransferase (depolymerizing) gene from Arthrobacter sp. H65-7 and its expression in Escherichia coli.

The gene encoding an extracellular inulin fructotransferase (depolymerizing) (inulase II) (EC 2.4.1.93), designated ift gene, was cloned from the genomic DNA of Arthrobacter sp. H65-7, and expressed in Escherichia coli for the first time. Sequence analysis showed a single open reading frame consisting of 1314 base pairs that encoded a signal peptide of 32 amino acids and a mature protein of 405 amino acids. The primary structure showed a homology of 49.8% with that of the inulin fructotransferase (DFA I-producing) (EC 2.4.1.200) from Arthrobacter globiformis S14-3. E. coli cells carrying the ift gene produced the active enzyme under control of the lac promoter. The expression of the ift gene was improved by a plasmid, pIFT-B, in which the ift gene was immediately downstream from the lac promoter. An E. coli transformant carrying pIFT-B expressed twice as much activity of inulase II as that of the original strain, Arthrobacter sp. H65-7. Most of the enzyme activity existed within the cells.

Amino Acid Sequence↗

PubMed1997

Domon L, an immunopotentiating agent, acts as an NF-kappaB activator.

Domon L, a heat-treated component of gram-negative bacterium Achromobacter stenohalis, is used for the treatment of infectious diseases of animals. Here, we investigated the immunopotentiating potential of Domon L. In vitro studies showed that Domon L enhanced nitric oxide (NO) formation from murine macrophage RAW264.7 cells in concert with interferon (IFN)-gamma. The effect of Domon L on NF-kappaB activation was investigated, in order to understand the molecular mechanisms of enhanced NO formation by Domon L. Domon L induced translocation of NF-kappaB to the nucleus in RAW264.7 cells. Induction of NF-kappaB dependent gene expression by Domon L was further confirmed using a transfectant containing an NF-kappaB-luciferase reporter gene. In vivo injection of Domon L elevated both serum IL-6 and mucoprotein, whose gene expression is partly under the control of NF-kappaB. The spleen cells of rats treated with Domon L produced much more NO when stimulated with LPS + IFN gamma than spleen cells of untreated rats. These results suggest that Domon L acts as an anti-infectious agent via NF-kappaB activation.

Achromobacter↗

PubMed1997

Effect of oestradiol on mRNA encoding GnRH receptor in pituitary tissue of orchidectomized sheep passively immunized against GnRH.

The effect of oestradiol on tissue concentrations of GnRH receptor and mRNA encoding GnRH receptor was assessed in orchidectomized sheep (wethers) made deficient in GnRH by passive immunization. Wethers were assigned to one of four groups (n = 6 animals per group). Animals in groups 2 and 4 received ovine anti-GnRH sera (200 ml; i.v.) at passive immunization, while antisera against the carrier protein was administered to wethers in groups 1 and 3. Oestradiol was delivered as a continuous infusion (2 micrograms h-1) to wethers in groups 1 and 2. Animals in groups 3 and 4 were infused with vehicle alone. Anterior pituitary tissue was collected at the end of the 48 h infusion. Anti-GnRH sera induced a rapid reduction in the serum concentration of LH. Continuous delivery of oestradiol resulted in a twofold increase (P < 0.05) in tissue concentration of GnRH receptor. This oestradiol-induced response was manifest even in wethers in which endogenous GnRH had been neutralized by passive immunization. Conversely, infusion of oestradiol increased (P < 0.05), and intravenous administration of anti-GnRH sera decreased (P < 0.05), concentrations of mRNA encoding GnRH receptor in pituitary tissue. When delivered in combination, anti-GnRH sera reduced (P < 0.05), but did not eliminate, the oestradiol-induced augmentation of steady-state concentrations of mRNA encoding GnRH receptor. These data demonstrate that the basal concentration of mRNA encoding GnRH receptor is dependent on continued GnRH stimulation. In contrast, the oestradiol-induced increase in steady-state concentration of mRNA encoding GnRH receptor is manifest even in the absence of GnRH.

Animals↗

PubMed1997

Concentration of GnRH receptor and GnRH receptor mRNA in pituitary tissue of orchidectomized sheep: effect of oestradiol, progesterone, and progesterone withdrawal.

The effect of progesterone (P4) and P4 withdrawal on oestradiol (E2)-induced change in gonadotrope responsiveness (GR) and concentration of GnRH receptor and GnRH receptor mRNA in pituitary tissue of orchidectomized sheep (wethers) was determined. Thirty wethers were assigned at random to one of six treatment groups (n = 5 animals/group). Wethers received E2 (2 micrograms/h; groups 2, 4, and 6) in 10% ethanol-saline (vehicle), or vehicle alone (groups 1, 3, and 5), as a continuous infusion for 24 h beginning 7 days after insertion (s.c.) of blank (groups 1 and 2) or P4-containing (groups 3-6) implants. The effect of P4 withdrawal was assessed by removing P4-containing implants at the beginning of vehicle (group 5) or E2 (group 6) infusion. Gonadotrope responsiveness (increase in serum LH induced by 500 ng GnRH, i.v.) was assessed at the end of infusion. In a companion study, anterior pituitary tissue was collected at the end of the 24-h infusion period. Infusion of E2 increased (P < 0.05) GR relative to GR noted in control wethers receiving vehicle alone. The magnitude of E2-induced augmentation of GR was not affected by concurrent administration of P4 or P4 withdrawal. Pituitary tissue concentrations of GnRH receptor and GnRH receptor mRNA were significantly reduced in wethers implanted with P4. This P4-induced decrease in tissue concentration of GnRH receptor and GnRH receptor mRNA was not reversed during the 24-h period after P4 withdrawal. Steady-state concentrations of GnRH receptor and GnRH receptor mRNA were significantly increased by E2. However, the magnitude of oestrogen-induced increase in tissue concentrations of GnRH receptor mRNA was not significantly affected by P4 or P4 withdrawal. Conversely, concurrent progestin stimulation potentiated the E2-induced augmentation of tissue concentrations of GnRH receptor. However, this P4-induced potentiation of the oestrogenic response was not evident 24 h after removal of the P4-containing implants. Steady-state concentrations of mRNA encoding the LH beta and FSH beta subunits were reduced (P < 0.05) by P4. Infusion of E2 had a similar affect. These data indicate that prolonged progestin stimulation leads to a decrease in tissue concentrations of GnRH receptor and GnRH receptor mRNA. This P4-induced suppression of GnRH receptor activity is not reversed within 24 h of P4 withdrawal. In addition, the increase n steady-state concentrations of GnRH receptor and GnRH receptor mRNA induced by E2 is not compromised by concurrent progestin stimulation.

Animals↗

PubMed1997

Concentration of gonadotropin-releasing hormone receptor messenger ribonucleic acid in pituitary tissue of orchidectomized sheep: effect of passive immunization against gonadotropin-releasing hormone.

The effect of immunoneutralization of gonadotropin-releasing hormone (GnRH) on LH secretion and concentrations of GnRH receptor, GnRH receptor mRNA, and gonadotropin subunit mRNA in pituitary tissue of orchidectomized sheep (wethers) was assessed. Thirty-six wethers were assigned at random to one of six treatment groups (six wethers per group). Thirty wethers (groups 2 to 6) received 200 ml, (i.v.) of anti-GnRH antisera at passive immunization (PI). Anterior pituitary tissue was collected .5, 1, 2, 4, or 8 d after PI from wethers in groups 2 to 6, respectively. Pituitary tissue was also collected from unimmunized wethers (Group 1). Intravenous administration of anti-GnRH sera increased anti-GnRH activity to 69.1 +/- 7% (percentage of total 125I-labeled GnRH bound by a 1:1,000 serum:GEL-PBS dilution) within 1 h of PI. Anti-GnRH activity declined gradually during the period after PI, and 8 d after PI anti-GnRH activity was 57.2 +/- 1.7%. Serum concentration of LH was significantly reduced, relative to the pretreatment (16.1 +/- 1.8 ng/mL) level, within 4 h (7.6 +/- 1.5 ng/mL) of PI, and the LH level was 10% of the pretreatment concentration 8 d after PI (1.6 +/- 0.2 ng/mL). Steady-state concentration of GnRH receptor mRNA decreased progressively during the period after PI and was significantly reduced, relative to the level in unimmunized control wethers (.44 +/- .03 pg/micron total RNA) d after PI. Tissue concentrations of GnRH receptor and mRNA for the alpha, LH alpha, and FISH beta subunits were also reduced (P < .05) by PI. These data indicate that maintenance of steady-state concentrations of GnRH receptor and GnRH receptor mRNA requires continued GnRH stimulation.

Animals↗

PubMed1997

Pharmacokinetic analysis of free radicals by in vivo BCM (Blood Circulation Monitoring)-ESR method.

In pharmacokinetic studies, a variety of analytical method including radioisotopic detection and HPLC (high performance liquid chromatography) has been used. In the present investigation, we developed in vivo BCM (Blood Circulation Monitoring)-ESR method, which is a new technique with a conventional X-band ESR spectrometer for observing stable free radicals in the circulating blood of living rats under anaesthesia. Both 5-(PROXYL derivatives) and 6-(TEMPO d derivatives) membered nitroxide spin probes with various types of substituent functional group were used. After physico-chemical properties of the spin probes such as hyperfine coupling constant (A-value), g-value and partition coefficient as well as chemical stability of the compounds in the fresh blood were obtained, the in vivo BCM-ESR method was performed in normal rats. Several pharmacokinetic parameters such as half-life of the probes, distribution volume, total body clearance and mean residence time were obtained and discussed in terms of their chemical structures. In addition, clearance of a spin probe was related to the urine concentration. The BCM-ESR method was found to be very useful to observe free radicals at the real time. By time-dependent ESR signal decay of spin probes, pharmacokinetic parameters were obtained.

Animals↗

PubMed1997

[Causes, diagnosis, and treatment of anemia in the elderly].

Healthy elderly people are mildly anemic peripheral blood data on 3,583 healthy elderly people (1,590 men and 1,993 women aged 65 years or older) from among those undergoing medical examinations at our hospital in the 8 years from 1988 to 1995 were compiled into 5-year age groups. For both men and women the mean values of red blood cell count, hemoglobin, and hematocrit were slightly lower among older subjects. The main causes of this apparent reduction may be a decrease in the number of hematopoietic stem cells and regression of the hematopoietic microenvironment. Observation of arteries in specimens of hematopoietic bone marrow obtained from the spines of elderly people showed arteriosclerotic changes such as greater hypertrophy of the media than of the intima, and adventitial fibrous hypertrophy. The number of venous sinuses was low and the amount of adipose tissue was high compared to the bone marrow of younger people. The cell density and the ratio of hematopoietic tissue to fat tended to be lower in older subjects. The number of erythroid burst-forming units formed after 14 days in culture medium containing erythropoietin was 28 +/- 19 in 32 healthy elderly people, which was significantly lower than the number in 30 young people 54 +/- 30, (p < 0.005). The value for erythroid colony-forming units was 170 +/- 67 in eight healthy people, which was much lower than in young people, 276 +/- 54. In the elderly subjects, the plasma iron disappearance time (PIDT/2) was 60-80 min (mean: 71.9 min), which was similar to that in the young, but the percent red cell iron utilization was 67.6%-84.9% (mean: 79.7%), which was slightly lower than in younger people. When the diagnostic criterion for anemia in the elderly was set at a hemoglobin value of 11.0 g/ dl, about 13% of outpatients who came to our Geriatrics department were found to have anemia, and in most of them the anemia had resulted from another disease. In conclusion, anemia in the elderly is likely to be affected by reduction in the function of various organs and by the decreased reserves associated with aging. The causes of anemia are complex and diagnosis is often difficult. The present article gives a general outline of the diagnosis and treatment of common types of primary and secondary anemia in the elderly.

Aged↗

PubMed1997

[Factors contributing to survival of elderly inpatients with chronic disease].

Clinical assessment and laboratory testing are important in predicting longevity and the outcomes of chronic diseases in the elderly. We therefore studied the prognostic utility of clinical and laboratory findings. A group of 168 elderly patients (70-97 years of age) with chronic diseases who were admitted to Kashiwazaki Kosei Hospital was studied. Data on 13 potentially prognostic factors were analyzed: dementia, being bedridden, anorexia, edema of the lower limbs, urinary incontinence, dyspnea fever, hepatic dysfunction, renal dysfunction, anemia, hypoalbuminemia, inflammation, and electrocardiographic abnormality. Kaplan-Meier survival curves were constructed, and either the log-rank or Wilcoxon method was used to look for significant differences in survival between patients with and without the factors listed above. Regression analysis was then done with the Coxproportional-hazards model to study the factors that contributed to the shortest survival. Patients lived longer if they were not bedridden, anorexic, incontinent of urine, hypoalbuminemic, or if they had no inflammation (p < 0.05): being bedridden, anorexia, urinary incontinence, hepatic dysfunction, hypoalbuminemia, inflammation, and electrocardiographic abnormalities. The survival curve obtained by using these factors as independent variables in the proportional-hazards model was similar to the Kaplan-Meier survival curve.

Aged↗

PubMed1997

[Pleural-origin malignant lymphoma in an elderly patient with chronic empyema and infection with the Epstein-Barr virus].

A 73-year-old woman with a long-standing history of right-sided chronic empyema complained of lumbago. An artificial pneumothorax had been induced to treat pulmonary tuberculosis about 40 years previously. The year after she began to complain of lumbago, a tumor mass over the right anterior chest wall had grown rapidly. Pathologic examination revealed that it was a malignant lymphoma (Non-Hodgkin's lymphoma, diffuse large cell, B cell type). Chemotherapy with cyclophosphamide, adriamycin, vincristine, and prednisolone, and then radiation therapy were given. The patient responded very well. The tumor mass on the surface of the chest wall disappeared completely. She was alive and well and there was no evidence of recurrence at the seven-month follow-up examination. Analysis with the polymerase chain reaction showed that the tumor contained DNA of the Epstein-Barr virus. The chronic empyema and local infection with the Epstein-Barr virus might have been a factor in the development of the malignant lymphoma.

Aged↗

PubMed1997

[Successful repair of combined cardiac rupture and septal perforation after myocardial infarction].

A 78-year-old woman was operated on with a diagnosis of oozing-type cardiac rupture after an acute anteroseptal myocardial infarction. Pericardial drainage was performed and hemostasis was obtained by dressing with local hemostatics. As hemodynamics improved, elevation of pulmonary artery pressure and a step-up in oxygen concentration in the pulmonary artery from a Swan-Ganz catheter sample appeared. A left-to-right shunt was observed in the operative field with color Doppler echocardiography and a diagnosis of ventricular septal perforation (VSP) was made. Subsequently, intracavitary repair with two sheets of equine pericardial patch, sutured using interrupted mattress sutures with felt pledgets, was performed. Her early course after operation was satisfactory in spite of a small residual shunt. However, thirty-one days later she was returned to surgery because of an increasing residual shunt. Looseness of several interrupted mattress sutures and thrombus adherent to the internal surface of the pericardial patch were observed. The thrombus was removed and the patch was reattached using both interrupted mattress sutures with felt pledgets and continuous suture. She had an uneventful recovery thereafter. As double rupture is not a rare complication after myocardial infarction, a careful hemodynamic examination is necessary and important in the diagnosis and treatment of cardiac rupture. We consider that interrupted mattress sutures are a better technique for early repair of the VSP to reduce a risk of residual shunt due to the weakness and unclear border of infarcted myocardial tissue, and continuous suture is acceptable to repair the VSP 3 to 4 weeks later after infarction. Long-term anticoagulant therapy is necessary after intracavitary repair using equine pericardial patch.

Aged↗

PubMed1997

Clinicopathologic factors influencing the long-term prognosis following hepatic resection for large hepatocellular carcinoma more than 10 cm in diameter.

We resected 158 cases of hepatocellular carcinoma (HCC), including 20 (12.6%) cases of large HCC. These 20 cases were divided into group 1 (curative resection, n = 9) and group 2 (noncurative resection, n = 11). The clinicopathologic features and long-term survival of the cases were evaluated. In groups 1 and 2, portal vein invasion (Vp+) was noted in 44.4% and 63.3%, intrahepatic metastasis (IM+) in 77.8% and 100%, absence of a fibrous capsule (Fc-) in 55.6% and 63.6%, and stage III or IV in 77.8% and 100%, respectively. The DNA ploidy pattern was aneuploid in 44.4% of group 1 and 100% of group 2. In group 1, the 1-, 3-, and 5-year cumulative survival rates were 75%, 62.5%, and 62.5%, respectively (the longest survivor is alive after 11 years 1 month). Five cases survived more than 3 years in group 1, and all were Vp(-) and nonaneuploid. On the other hand, in group 2, the 1-year survival rate was only 33.3%; none survived more than 2 years. These results suggest that even patients with large HCC have a favorable long-term prognosis if their clinicopathologic factors are Vp(-) and nonaneuploid, and if curative resection can be performed.

Adult↗

PubMed1997

Ectopic lacrimal gland of the orbit.

A case of intraorbital ectopic lacrimal gland was evaluated with various radionuclides. CT and MRI with contrast enhancement showed a soft-tissue mass in the orbit. The lesion was gallium-avid, but 18F-FDG PET demonstrated very faint uptake. On early and delayed 201Tl-Cl images, mildly increased uptake and mild retention were observed. Technetium-99m-(V)-DMSA SPECT showed intense accumulation on both the early and delayed images. Technetium-99m-pertechnetate SPECT, demonstrating marked uptake in the lesion, was useful for the differential diagnosis between intraorbital malignancy and this benign lesion. These scintigraphic variations played an important role in the tissue characterization of this uncommon lesion.

Child↗

PubMed1997

[Radionuclear estimation with 99mTc-N-pyridoxyl-5-methyl-tryptophan (PMT) scintigraphy of recurrent hepatocellular carcinoma after non-surgical treatment].

99mTc-N-pyridoxyl-5-methyl-tryptophan (PMT) scintigraphy, which exhibits highly specific for the diagnosis of primary hepatocellular carcinoma (HCC), was performed for recurrent HCC following non-surgical treatment. Eighty-four patients (total 351 examinations) were selected for the study. The ability of PMT scintigraphy to diagnose recurrent HCC after treatment was compared with that of computed tomography, ultrasonography and angiography. The results showed that 1) sixty-three (75%) of 84 cases demonstrated positive findings during our follow-up period, 2) most of the tumors initially showing positive findings remained PMT positive when they recurred and 3) PMT studies shortly after treatment demonstrated wider tracer uptake rather than the actual tumor area. In conclusion. PMT scintigraphy for patients with HCC after non-surgical treatment exhibited high accuracy in identifying viable HCC only for tumors indicating positive findings.

Aged↗

PubMed1996

Rapid attenuation of AP-1 transcriptional factors associated with nitric oxide (NO)-mediated neuronal cell death.

Stimulation of glutamate receptors causes several intracellular reactions including activation of activator protein-1 (AP-1) production and nitric oxide (NO) generation. Exposing mouse cerebellar granule cells to N-methyl-D-aspartate or kainate (KA) in culture induced an increase of AP-1 DNA binding activity that was blocked by further addition of sodium nitroprusside (SNP), a typical NO donor. Immunoblotting using anti-c-Fos antiserum revealed the specific attenuation of AP-1, although total protein synthesis was not affected. Since the level of c-fos mRNA expression stimulated by KA remained constant even after exposure to SNP, the AP-1 attenuation can be post-transcriptionally induced. SNP did not affect the Ca2+ influx into the cells stimulated by KA. The involvement of NO in the AP-1 attenuation was supported by the fact that potassium ferrocyanide (K4Fe(CN)6), an analogue of SNP but devoid of NO, failed to inhibit the AP-1 DNA binding activity stimulated by KA. SNP alone induced neuronal cell death, which was blocked by the simultaneous addition of antioxidants, superoxide dismutase and catalase, and an NO scavenger, suggesting a direct role of peroxynitrite in the cell death. In good agreement with these effects, the AP-1 attenuation by SNP was also blocked by antioxidants. These results indicated that post-transcriptional attenuation of AP-1 is involved in the early processes of NO-mediated neuronal cell death.

Animals↗

PubMed1996

Electronic and vibrational structure of the radical cation of P840 in the putative homodimeric reaction center from Chlorobium tepidum as studied by FTIR spectroscopy.

Light-induced FTIR difference spectra of P840 upon its oxidation (P840+/P840) have been measured with the reaction center complex from the green sulfur bacterium Chlorobium tepidum. A broad band centered near 2500 cm-1 was observed in P840+, which is comparable to the band near 2600 cm-1 previously observed in P870+ of purple bacteria and assigned to the electronic transition in the bacteriochlorophyll a (BChla) dimer (Breton et al. (1992) Biochemistry 31, 7503-7510]. The intensity of this electronic band found in P840+ was about the same as that in P870+. The P840+ spectrum also showed several intensified vibrational modes, which are characteristic of the P870+ spectrum as well. These similar features of the electronic transition and the intensified lines indicate that P840+ is a BChla dimer whose electronic structure is similar to P870+. Based on the previous theoretical works, the possibility that P840+ has an asymmetric structure as P870+ was suggested. Also, two strong positive bands at 1707 and 1694 cm-1 probably assigned to the keto C9 = O stretching modes of P840+ were observed in the P840+/P840 spectrum. Three different interpretations are possible for the presence of the two C9 = O bands: (i) P840+ is an asymmetric dimer cation. (ii) P840+ has a symmetric structure, and the time constant of positive charge exchange between the two BChla molecules coincides with that of IR spectroscopy (10-13 s). (iii) The electric field produced by the positive charge on P840+ affects the C9 = O frequency of the neutral BChla in P840+ itself (when the charge exchange time is slower than the time scale of 10-13 s) or of a BChla in the close proximity of P840+. The negative bands at 1734 and 1684 cm-1 were assigned to the ester C10 = O and the keto C9 = O of neutral P840, respectively, both of which are free from hydrogen bonding. These results and interpretations regarding the structural symmetry and the molecular interactions of P840 and P840+ are discussed in the framework of the "homodimeric" reaction center of green sulfur bacteria.

Chlorobi↗

PubMed1996

Core promoter elements are essential as selective determinants for function of the yeast transcription factor GAL11.

The GAL11 gene product, which copurifies with RNA polymerase II holoenzyme, is necessary for full expression of many, but not all, genes in yeast. Here we shows that the GAL11 dependence of a gene for expression is determined by the core promoter structure. In the GAL80 gene, a gal11 null mutation caused reduction of TATA-dependent transcription, but exerted no effect on initiator-mediated transcription. GAL11 stimulated TATA-dependent transcription, but did not affect the TATA-independent transcription in HIS4. GAL11 was also required for transcription mediated by a canonical TATA sequence but not by a nonconsensus TATA sequence of HIS3. These results suggest that GAL11 is specifically involved in the transcription machinery formed on the TATA element.

Fungal Proteins↗

PubMed1996

Subunit composition of RNA polymerase II from the fission yeast Schizosaccharomyces pombe.

The subunit composition of RNA polymerase II (polII) was compared between the budding yeast Saccharomyces cerevisiae and the fission yeast Schizosaccharomyces pombe. For this purpose, we partially purified the enzyme from S. pombe. Judging from the co-elution profiles in column chromatographies of both the RNA polymerase activity and the two large subunit polypeptides (subunit 1 (prokaryotic beta' homologue) and subunit 2 (beta homologue)), the minimum number of S. pombe polII-associated polypeptides was estimated to be ten, less than the proposed subunit number of the S. cerevisiae enzyme. These ten putative subunits of S. pombe polII correspond to subunits 1, 2, 3, 5, 6, 7, 8, 10, 11 and 12 of the S. cerevisiae counterparts.

Binding Sites↗