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T Sano

Publications and source records attributed to T Sano.

At least 415 records · Page 23Linked to original sources
PubMed1994

Kinetics of the quaternary structure change of aspartate transcarbamylase triggered by succinate, a competitive inhibitor.

The quaternary structural change of Escherichia coli aspartate transcarbamylase (ATCase) was studied by time-resolved X-ray solution scattering following the binding of carbamoyl phosphate and of succinate, a competitive inhibitor of the natural substrate L-aspartate. Stopped-flow experiments at sub-zero temperatures in the presence of 30% ethylene glycol allowed us to monitor the evolution of the scattering pattern, including the characteristic scattering peak in an s (=2 sin theta/lambda) range of 0.01-0.06 A-1. The inhibitor binding promotes a quaternary structure change from the T state toward the R state, and as expected for a simple ligand binding process, ATCase remains in the R state, unlike the physiological enzyme reaction [Tsuruta, H., et al. (1990) FEBS Lett. 263, 66-68]. After equilibrium had been established, the final scattering pattern was recorded. When the succinate concentration was sufficiently high, this pattern was the same as that given by ATCase saturated with the bisubstrate analogue N-phosphonoacetyl-L-aspartate (PALA). This implies that, under cryogenic conditions, succinate and carbamoyl phosphate promote the same quaternary structure change as PALA, which is in good agreement with the crystallographic studies of Gouaux and Lipscomb [Gouaux, J.E., & Lipscomb, W.N. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 4205-4208]. Scattering patterns recorded during the course of the structural transition were satisfactorily reproduced by a linear combination of the initial and final patterns, suggesting that there is no significant concentration of quaternary structure intermediates between the T and R states. This is consistent with a concerted structural transition of ATCase.(ABSTRACT TRUNCATED AT 250 WORDS)

Aspartate Carbamoyltransferase↗
PubMed1994

rbcL gene sequences provide evidence for the evolutionary lineages of leptosporangiate ferns.

Pteriodophytes have a longer evolutionary history than any other vascular land plant and, therefore, have endured greater loss of phylogenetically informative information. This factor has resulted in substantial disagreements in evaluating characters and, thus, controversy in establishing a stable classification. To compare competing classifications, we obtained DNA sequences of a chloroplast gene. The sequence of 1206 nt of the large subunit of the ribulose-bisphosphate carboxylase gene (rbcL) was determined from 58 species, representing almost all families of leptosporangiate ferns. Phlogenetic trees were inferred by the neighbor-joining and the parsimony methods. The two methods produced almost identical phylogenetic trees that provided insights concerning major general evolutionary trends in the leptosporangiate ferns. Interesting findings were as follows: (i) two morphologically distinct heterosporous water ferns, Marsilea and Salvinia, are sister genera; (ii) the tree ferns (Cyatheaceae, Dicksoniaceae, and Metaxyaceae) are monophyletic; and (iii) polypodioids are distantly related to the gleichenioids in spite of the similarity of their exindusiate soral morphology and are close to the higher indusiate ferns. In addition, the affinities of several "problematic genera" were assessed.

Base Sequence↗
PubMed1994

Enhanced DNA sequencing by hybridization.

An enhanced version of DNA sequencing by hybridization (SBH), termed positional SBH (PSBH), has been developed. PSBH uses duplex probes containing single-stranded 3' overhangs, instead of simple single-stranded probes. Stacking interactions between the duplex probe and a single-stranded target should provide enhanced stringency in distinguishing perfectly matched 3' sequences. A second enhancement is the use of enzyme-catalyzed steps, instead of pure physical hybridization. The feasibility of this scheme has been investigated using biotinylated duplex probes containing single-stranded 5-base 3' overhangs, immobilized on streptavidin-coated magnetic beads. Ligation of a single-stranded target, hybridized to the single-stranded region of the duplex probes, provided enhanced discrimination of perfectly matched targets from those containing mismatches. In distinction to the serious complications caused by base composition effects in ordinary SBH, there was little effect of base composition in PSBH. The hardest mismatch to discriminate was the one furthest from the phosphodiester bond formed by ligation. However, mismatches in this position were efficiently discriminated by 3' extension of the duplex probe using a template-dependent DNA polymerase. These results demonstrate that PSBH offers considerable promise to facilitate actual implementations of SBH.

Base Sequence↗
PubMed1994

Measurement of serum Lp(a) by COBAS MIRA using a latex immunoturbidimetric assay kit.

We had an opportunity to test a reagent kit for serum lipoprotein (a) [Lp(a)] assay, which was based on the latex immunoturbidimetric assay method, and applied it to COBAS MIRA (Roche). Reproducibility of the assay procedure was 0.92-4.0% CV of three samples which contained 12.58-60.4 mg/dl of Lp(a). Minimum detectable concentration was 1.5-2.0 mg/dl. It was confirmed that interference of co-existing substances, i.e. hemoglobin, bilirubin, and intralipid, was negligible. No cross reactivity was seen with plasminogen. Correlation with a ELISA method was excellent. Frequency distribution of Lp(a) in healthy Japanese was similar to that found in white population.

Cross Reactions↗
PubMed1994

Isolation and mapping of cosmid markers on human chromosome 22, including one within the submicroscopically deleted region of DiGeorge syndrome.

A genomic cosmid library was constructed from a Chinese hamster/human hybrid cell containing human intact chromosome 22 as its only human component. Of 1000 cosmids with inserts derived from human chromosome 22, 191 were tested for restriction fragment length polymorphisms (RFLPs). As a result, 64 clones detected RFLPs, including five variable number of tandem repeats systems. Of the remaining 127 cosmids, 111 detected a single copy sequence on human chromosome 22. Five somatic cell hybrids allowed us to assign all of the 64 polymorphic cosmids and 44 non-polymorphic cosmids to four different regions of human chromosome 22. In two patients with DiGeorge syndrome, one of the cosmids that had been sublocalized to 22pter-q11 detected hemizygosity. These 108 cosmid markers regionally assigned to human chromosome 22 should be useful for the construction of long-range physical maps and the identification of genetic alterations on the chromosome.

Animals↗
PubMed1994

The macroscopic diagnosis of lymph node metastasis from early gastric cancer.

As the proportion of early gastric cancers (EGC) has been steadily increasing, modifications of the "radical lymphadenectomy" approach to stomach cancer have been attracting considerable attention; however, accurate pre- and intraoperative evaluations of tumor extent are essential for the successful application of this method. We examined the reliability of macroscopically diagnosing node involvement by reviewing the operative and pathological records of 522 patients with EGC. Of 59 patients histologically diagnosed as node-positive (n+), only 19 (32%) had been macroscopically diagnosed as node-positive (N+). In contrast, of 61 N+ patients, 42 (69%) were in fact n-. Metastases from histologically diffuse type carcinomas were less accurately diagnosed than those from intestinal type tumors. In 44% of the false-positive (N+/n-) patients, the tumor had been preoperatively diagnosed as advanced, which seemed to have lead to intraoperative overdiagnosis. These results suggest that lymph node metastases from EGC cannot be reliably diagnosed during surgery. The indications for a modified radical operation should thus be decided according to preoperative tumor evaluation based on the depth of invasion.

Humans↗
PubMed1994

Sexual difference in the incidence of diabetes mellitus in Otsuka-Long-Evans-Tokushima-Fatty rats: effects of castration and sex hormone replacement on its incidence.

The incidence of non-insulin-dependent diabetes mellitus in a model rat (Otsuka-Long-Evans-Tokushima Fatty [OLETF]) has been shown to be much higher in males than in females. To evaluate the role of sex hormones in the development of diabetes in this model, we performed biochemical and morphological studies on the effects of castration and sex hormones on the development of non-insulin-dependent diabetes mellitus in these rats. The rats were randomly assigned to six groups of 10 rats each, three groups of males and three of females. Two of the male groups and two of the female groups were castrated at 5 weeks of age, and the third male and female groups received sham operations. From 9 to 30 weeks of age, one group of castrated males received testosterone enanthate (1 mg-wk-1) and one group of castrated females received estradiol valerate (1 mg.wk-1). The other castrated groups received an equal volume of vehicle only. At 30 weeks of age, the cumulative incidences of diabetes mellitus in the sham-operated male and female rats were 100% and 0%, respectively. Orchiectomy reduced the incidence of diabetes to 20%, whereas ovariectomy increased it to 30%. Administration of sex hormones restored the incidence to 89% in males and 0% in females. In vivo insulin-stimulated glucose uptake as measured with a euglycemic clamp was reduced in sham-operated males, castrated males with hormone replacement (HR), and castrated females without HR as compared with sham-operated females and castrated females with HR.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Angiography of the temporomandibular joint. Description of an experimental technique with initial results.

The vascular supply to the temporomandibular joint is not completely understood. To form a base for advancement in this area we developed a method for experimental angiography of the temporomandibular joint that was applied to fresh temporomandibular joint autopsy specimens. Via the external carotid artery the vessels were infused with a mixture of barium and an acrylic resin. The specimens were sectioned and contact radiographs were obtained. These showed the vascularity of the joint and the surrounding structures with great detail. Most of the vascular supply appears to come from the lateral and medial aspects of the condyle head and from the anterior and posterior disk attachments. The method was applied to both normal and abnormal joints and the results suggest that this method could be used to gather further understanding of the vascularity of the temporomandibular joint relative to disease.

Aged↗
PubMed1994

Effects of difference in amount of exercise training on prevention of diabetes mellitus in the Otsuka-Long-Evans-Tokushima fatty rats, a model of spontaneous non-insulin-dependent diabetes mellitus.

Exercise training every day has been shown to be effective in preventing the development of non-insulin-dependent diabetes mellitus (NIDDM) in a model rat (Otsuka Long Evans Tokushima Fatty (OLETF)). For determination of whether less vigorous exercise training also has a protective effect against the development of NIDDM in this model, seven male OLETF rats each were assigned to training every other day, every 3 days and every 7 days from 6 to 30 weeks of age. At 30 weeks of age, rats trained every other day, 3 days, 7 days and sedentary rats weighed averages of 547, 548, 603 and 695 g and had abdominal fat deposits of 28, 24, 32 and 72 g, respectively. The mean meterages of running of rats trained every other day, 3 days and 7 days over the whole experimental period were 9630, 5166 and 1685 m/week, respectively. At 30 weeks of age, the cumulative incidence of NIDDM in sedentary rats was 85.7% (6/7), while none of the trained rats became diabetic except for one of rats trained every 7 days. The glucose infusion rate (GIR), an index of insulin sensitivity, in the group trained every 7 days, 60.6 +/- 5.0 mumol.kg-1.min-1, was significantly greater than that in the sedentary group, 21.7 +/- 1.7 mumol.kg-1.min-1. Morphological studies on the pancreas of rats trained every other day and every 3 days showed minimal changes of islets, whereas sections of islets from rats trained every 7 days appeared enlarged and fibrotic, though significantly less so than the islets of sedentary rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Transgenic expression of IL-10 in pancreatic islet A cells accelerates autoimmune insulitis and diabetes in non-obese diabetic mice.

To study the paracrine effect of IL-10 on autoimmune insulitis and diabetes, we produced IL-10 transgenic non-obese diabetic (NOD) mice (NOD-IL-10) in which murine IL-10 was expressed in pancreatic islet A cells under the control of a rat glucagon promoter without directly manipulating pancreatic islet B cells. Among 11 founder mice, four of four males and three of seven females developed diabetes by 10 weeks of age. Histological analysis of six NOD-IL-10 revealed severe insulitis and prominent ductal proliferation. NOD-IL-10 also showed spotty lymphocytic infiltration in the lung and liver in four of six founder mice. The onset of diabetes in NOD-IL-10 was remarkably earlier than that of 14 weeks of age at the earliest in female non-transgenic NOD mice. When the NOD-IL-10 mouse was backcrossed to C57BL/6 mice, none of the resulting F1, B-N2 or B-N3 generation toward C57BL/6 mice showed diabetes even at 39 weeks of age, in spite of the presence of peri-insulitis and prominent ductal proliferation, while two of four mice of the N-N2 generation toward NOD mice showed early-onset diabetes. Thus, transgenic paracrine expression of IL-10 in situ in the NOD genetic background enhances autoimmune insulitis and diabetes in their onset and severity, ignoring gender difference. Because expression of IL-10 was detected by polymerase chain reaction in pancreatic islets of non-transgenic NOD mice after 5 weeks of age, IL-10 secreted in situ is regarded to enhance cell-mediated autoimmune diabetes, in spite of established in vitro anti-Th1 activity of IL-10.

Animals↗
PubMed1994

In vitro and in vivo cytogenetic effects of recombinant interleukin-2 on human lymphocytes.

To determine the cytogenetic effects of rIL-2, we investigated the rIL-2-induced sister chromatid exchange (SCE) and chromosomal aberrations in human peripheral lymphocytes in vitro and in patients given rIL-2 as a 24-hour infusion for 28 consecutive days. No significant increase in SCE frequency and chromosomal aberrations was observed after in vitro incubation of lymphocytes with 100 U/ml of rIL-2. A daily rIL-2 dose of 6.6 x 10(5) U/m2 did not induce any significant effect on SCE frequency and chromosomal aberrations while a marked increase was observed in the percentage of IL-2 receptor positive cells and HLA-DR positive cells. Although IL-2 therapy is only in developmental stage, our results suggest there is little or no potential mutagenic and/or carcinogenic hazard with this agent.

Aged↗
PubMed1994

Growth hormone and prolactin gene expression in human densely and sparsely granulated somatotroph adenomas by in situ hybridization with digoxigenin-labeled probes.

We studied growth hormone (GH) and prolactin (PRL) messenger ribonucleic acids (mRNAs) in 14 cases with densely granulated somatotroph (DG) adenomas and 10 cases with sparsely granulated somatotroph (SG) adenomas using in situ hybridization with digoxigenin-labeled probes and correlated these data with their immunohistochemical results. A good correlation between in situ hybridization results and immunohistochemical data was found in most cases examined. The DG adenomas generally had a diffuse and intense GH immunoreactivity and GH hybridization signal, whereas in SG adenomas the number of cells exhibiting a GH mRNA signal and the strength of the GH mRNA signal in these cells were relatively lower than those of DG adenomas, indicating that lower expression of the GH mRNA signal is responsible for lower GH production in SG adenomas. In addition, PRL mRNA expression differed in the two types of adenoma; in DG adenomas, seven cases (50%) expressed PRL mRNA signal with a focal or scattered distribution despite normal serum PRL levels, but two showed no PRL immunoreactivity. In contrast, in SG adenomas, only one case contained a few cells possessing a PRL mRNA signal despite having no PRL immunoreactivity. It can be concluded that DG and SG adenomas, which have been considered variants of the same tumor, display definite differences as to GH or PRL gene expression in each type of adenoma.

Adenoma↗
PubMed1994

Splenectomy for treatment of immunoblastic lymphadenopathy.

A 5-month-old girl was diagnosed with immunoblastic lymphadenopathy (IBL) on the basis of clinical symptoms and pathological findings. alpha-interferon, immunosuppressive agents such as cyclosporin A, deoxyspagarine, and azathioprine, and an alternating regimen of low-dose 6-mercaptopurine, cyclophosphamide and methotrexate were tried with partial success. Finally, splenectomy was carried out at 58 months of age, inducing prolonged complete remission without any medication.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Histologic and immunohistochemical study of clinically non-functioning pituitary adenomas: special reference to gonadotropin-positive adenomas.

Seventy-five clinically non-functioning pituitary adenomas were characterized in terms of their histologic and immunohistochemical features. Fourteen adenomas (18.7%) were positive for hormones other than gonadotropins. These included two somatotroph adenomas, three lactotroph adenomas, four thyrotroph adenomas, four corticotroph adenomas and one unusual plurihormonal adenoma. Fifty-five adenomas (73.3%) were exclusively positive for one or more gonadotropin subunits (beta-follicle stimulating hormone, beta-luteinizing hormone, and alpha-subunit of glycoprotein hormones), but negative for other hormones such as growth hormone and beta-thyrotropin. Histologically, a papillary arrangement along the capillary was most characteristically observed in the gonadotropin-positive adenomas. Five of six adenomas negative for any pituitary hormones exhibited the typical papillary structure. Thus, approximately 80% of clinically non-functioning adenomas constituted a single tumor group that shared the common histologic features of gonadotroph adenomas. These findings suggest that nearly all tumor types of clinically non-functioning adenomas can be diagnosed solely by light microscopy in combination with immunohistochemistry, and that the vast majority of them may be gonadotroph adenomas.

Adenoma↗
PubMed1994

Effects of droperidol, pentobarbital, and ketamine on myogenic transcranial magnetic motor-evoked responses in humans.

Myogenic motor-evoked responses to transcranial magnetic stimulation of the motor cortex (tcmag-MERs) may become clinically useful for the noninvasive assessment of motor pathway conduction during surgery. However, application is hindered because most anesthetic regimens result in severe depression of tcmag-MER amplitudes. As part of our systematic attempts to identify anesthetic agents and supplements suitable for use during tcmag-MER recording, we studied the effect of bolus doses of pentobarbital (1.5 mg/kg), droperidol (0.07 mg/kg), or ketamine (1 mg/kg), administered intravenously, on compound muscle action potentials to transcranial magnetic stimulation in five healthy volunteers. The doses were chosen to be comparable with doses that might be suitable for supplementation of a nitrous oxide/opioid anesthetic technique. Droperidol administration resulted in sustained amplitude depression of both tibialis and adductor pollicis tc-MERs to 30 +/- 9% and 39 +/- 14% of baseline (P < 0.01). Tcmag-MER amplitude changes after pentobarbital were variable, ranging from no change to substantial amplitude depression (to 20% of baseline) in two subjects. In contrast, ketamine administration did not result in significant amplitude depression. In three subjects, tibialis anterior amplitude increased to 150 to 220% of control values in the first 10 minutes after ketamine. Onset latency was unchanged after any drug. These data indicate that tcmag-MERs are moderately depressed after droperidol and pentobarbital but well preserved after ketamine. Ketamine may be a more suitable supplement to opioid/nitrous oxide anesthesia than droperidol or pentobarbital.

Adult↗
PubMed1994

Prognosis of patients with severe congestive heart failure referred to the cardiac transplant program. Osaka University Cardiac Transplant Program.

In any program for cardiac transplantation, appropriate recipient selection is critically important. The purpose of this study is to evaluate the prognosis of 42 patients with severe cardiac dysfunction who were referred to the Patient Referral Committee of the Osaka University Cardiac Transplant Program from August 1990 to July 1993. All of the patient profiles and clinical data were presented and discussed in the Committee Conference. The Committee classified the patients into three groups according to the following criteria: Class A; 14 patients judged to have a medical indication for heart transplantation, Class B; 7 patients with possible indications which required reevaluation for a definite indication after further intensive medical treatments, and Class C; 21 patients who did not have indications for heart transplantation or who required further clinical examinations and/or medical treatments before a final judgment. Twelve of the 14 Class A patients had a history of NYHA functional class IV and ejection fractions were 25% or less in all of the patients but one (18.5 +/- 1.7%). Six patients in Class A had a history of ventricular tachycardia. The one-year survival rate of Class A patients was 60%, and only 28% survived for 28 months. One patient underwent successful heart transplantation in the United States. If we assume that this patient would have died within a year without heart transplantation, the estimated one-year survival rate would fall to 48%, which is comparable to the survival rate of patients who have been accepted for transplant, but are being treated medically, in Western countries.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1994

Effects of strontium on calcium metabolism in rats. I. A distinction between the pharmacological and toxic doses.

Strontium at low doses has been used to treat osteoporosis. However, excessive doses can disturb calcium metabolism. The aim of the present study was to determine a dose that does not have any significant toxic effects on calcium contents in bone and calcium metabolism, and, consequently, to distinguish between pharmacological and toxic doses in rats. The rats were divided into a control, 0.05%-Sr, 0.10%-Sr and 0.50%-Sr groups (strontium intake approx. 0, 87.5, 175 and 875 mumol/day, respectively). All of the rats were pair-fed their respective diets containing various doses of strontium in single metabolic cages from when they were 36 to 63 days old. When the rats were 60 days old, bone formation, bone resorption, calcium balance and intestinal calcium absorption were calculated as calcium metabolic parameters over a 3-day period using calcium balance and kinetic studies. At the age of 64 days, the rats were sacrificed under anesthesia, and the femur and blood were collected. Calcium and strontium levels in the bone and serum were then measured. In the strontium groups that received less than 175 mumol/day, none of the calcium metabolic parameters were significantly affected. However, the calcium contents in the bone were significantly increased in the group that received 87.5 mumol/day group. On the other hand, in the group that received the highest dose of strontium (875 mumol/day), all of the calcium metabolic parameters measured were markedly suppressed. A decrease in calcium level in both the bone and serum was also observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗