Biomedical subjects

Y Kai

Publications and source records attributed to Y Kai.

At least 145 records · Page 8Linked to original sources

PubMed1992

Three-dimensional structure of ferricytochrome c' from Rhodospirillum rubrum at 2.8 A resolution.

The structure of ferricytochrome c' extracted from Rhodospirillum rubrum has been determined by the X-ray crystallographic method. Crystals in hexagonal space group P6(1), with unit-cell dimensions a = b = 51.72 A and c = 155.49 A, contain one dimer molecule composed of chemically identical polypeptide chains (monomer I and monomer II) per asymmetric unit. An electron density map has been calculated at a resolution of 2.8 A by the multiple isomorphous replacement method using four-circle diffractometer data from native crystals and two heavy-atom derivatives. The quality of the map was improved by averaging the electron density about the non-crystallographic 2-fold axis relating the two monomers. The initial three-dimensional model of monomer I was built on a computer graphics system and that of monomer II was derived from monomer I using the non-crystallographic symmetry matrices. The dimer structure has been refined using a combination of simulated annealing and conventional restrained least-squares crystallographic refinement. The current model includes 244 amino acid residues (122 x 2) and 2 hemes, with a root-mean-square deviation in bond lengths from ideal values of 0.022 A. The current crystallographic R-factor is 23.3% for 4,481 independent reflections [magnitude of Fo greater than or equal to sigma (F)] between 5.0 and 2.8 A resolution. The monomer molecule is structurally organized as an array of four nearly parallel alpha-helices which construct a left-twisted bundle. One end of the bundle, in which a covalently bound protoheme IX prosthetic group is incorporated, is more divergent than the other.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗

PubMed1992

[Clinical studies of efficacy of imipenem/cilastatin sodium against urinary tract infections with ureterocutaneostomy].

Clinical efficacy of IPM/CS against urinary tract infections (UTI) was evaluated on 19 patients with malignancies (bladder tumor: 15, prostate cancer: 3, uterus cancer: 1) and 1 patient with a benign disorder (ureter stenosis) who had undergone ureterocutaneostomy between January, 1988 and December, 1990. Their ages ranged from 42 to 79 years. Postoperatively, they had UTI with pyuria of greater than or equal to 5/hpf and bacteriuria of greater than or equal to 10(4)/ml. IPM/CS was administered at a dose of 0.5 g (0.25g/0.25 g) twice a day through intravenous drip infusion. Its efficacy was evaluated according to the UTI criteria for clinical evaluation as ruled by the Japanese Society of Chemotherapy. Overall clinical value was rated "excellent" in 4 (20%), "moderate" in 9 (45%) and "poor" in 7 (35%) cases for a total of 65%. The efficacy by types of infection was 33% and 70.6% in the group of single infection and in the group of mixed infection, respectively. As to bacteriological efficacy 34 of the 38 strains (89.5%) isolated were eradicated following its administration. The eradication rate was 84.6% for P. aeruginosa, and 84.6% for E. faecalis. Microbes which appeared after its dosing amounted to 6 classes of 17 strains, 6 NFB strains of which were identified. As a side effect, elevation of serum GPT (5%) was noted. Regardless of the underlying conditions (malignant diseases and ureterocutaneostomy), clinical efficacy of IPM/CS was appreciable. In addition, the MIC for (P. aeruginosa, E. faecalis) of IPM/CS was lower than that of PIPC.

Adult↗

PubMed1991

Preliminary crystallographic study of a pseudoazurin from methylotrophic bacterium, Methylobacterium extorquens AM1.

Single crystals of pseudoazurin, one of the blue copper proteins produced by methylotrophic bacterium Methylobacterium extorquens AM1, have been obtained by the method of vapor diffusion with ammonium sulfate as a precipitant at pH 8.0. Crystals belong to the orthorhombic system, space group P2(1)2(1)2(1), with unit cell dimensions of a = 52.619(4) A, b = 63.280(6) A, c = 35.133(4) A. The asymmetric unit includes one molecule of pseudoazurin (Vm = 2.18 A3/dalton). The crystals are so stable against X-ray irradiation that diffraction intensities of the native crystal up to 1.68 A resolution could be collected from only one crystal. Among the many heavy-metal reagents examined, uranyl acetate gave an effective isomorphous derivative.

Azurin↗

PubMed1991

Sex-dependent body weight changes after iontophoretic application of kainic acid into the LH or VMH.

Body weight changes and food and water intakes were studied in CFY male and female rats after kainic acid (KA)-induced destruction of the lateral hypothalamic area (LH) or the ventromedial hypothalamic nucleus (VMH). To minimize the extent of damages, KA was iontophoretically applied by means of glass micropipettes. KA was ejected in 50 or 80 mM concentrations with 5-15 microA current for 5 min. Tip diameter of pipettes varied between 10-20 microns. Lesions were restricted to the LH or VMH. Effects were sex-dependent. LH lesions resulted in hypophagia, hypodipsia and body weight loss only in male rats. On the other hand, only female animals exhibited hyperphagia and weight increase when the VMH was destroyed. The role of sex-dependence in hypothalamic body weight regulation is discussed.

Animals↗

PubMed1991

Crystallization and main-chain structure of neutral protease from Streptomyces caespitosus.

A neutral protease, i.e., a zinc-containing metalloendoprotease from Streptomyces caespitosus, has been crystallized using acetone as a precipitating agent. The crystals diffract to better than 1.5 A resolution when a rotating anode X-ray generator is used as an X-ray source. Protein phase angles were calculated by the multiple isomorphous replacement method using two heavy-atom derivatives (HgCl2 and CH3HgCl). A 6 A resolution electron density map clearly showed molecular boundaries. Although its amino acid sequence is not known, the folding pattern of the polypeptide chain could be traced on a 2.5 A resolution electron density map. A large cleft, which is located on the molecular surface, was proved to be the active site of the enzyme by structure analyses of inhibitor-complex crystals. The highest electron density peak, which corresponds to the cleft, was assigned to a catalytically essential zinc atom on difference Fourier synthesis between native and EDTA-soaked crystals.

Binding Sites↗

PubMed1991

Selective synthesis of 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine as a protein modifier.

2,4-Bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine, a protein modifier with two polyethylene glycol chains (activated PEG2) was synthesized from monomethoxypolyethylene glycol and cyanuric chloride using zinc oxide as a catalyst by the improved method of a previous study (Matsushima et al., Chem. Lett. 7, 773, 1980). The product was identified as activated PEG2 without contamination of by-products with chromatographic and structural analysis.

Catalysis↗

PubMed1991

[Clinical evaluation of the bladder tumor marker "Tu-MARK-BTA"].

Bladder tumor antigen (BTA) is a tumor marker isolated from the urine of individuals with TCC of the bladder. This antigen can be detected by the Tu-MARK BTA test, a simple and rapid slide latex agglutination test performed on freshly voided urine. Sensitivity and specificity of BTA were calculated, and the correlation with pathological grade, histological stage, and urinary findings were statistically evaluated (chi 2-test) in 110 patients (72 male, 38 female; age: 16-91, mean age 54.4) examined between September, 1989 and April, 1990 including 46 TCC of the bladder (primary 28, secondary 18; grade 1:10, grade 2:27, grade 3:9, pTis: 2, pTa: 2, pT1: 23, pT2: 5, pT3: 4, pT4: 2), and 64 benign diseases. Sensitivity was 45.6%, specificity was 60.9%. In bladder tumor cases a correlation was seen between BTA and stage (p less than 0.02), and between BTA and grade (P less than 0.05). The positive ratio was higher in T1-T4 (55.9%) than in Tis.Ta (p less than 0.02). A high positive ratio of BTA was seen in bladder tumor cases with hematuria (70%, p less than 0.01) and pyuria (86.7%, p less than 0.01). This method is easy and rapid and the values are highly correlated with stage. Therefore, it should be useful for not only screening but followup of bladder tumor. Furthermore, BTA in combination with urine cytology is a more useful way for diagnosing TCC of the bladder.

Adolescent↗

PubMed1990

Lymphocytic adenohypophysitis accompanying occlusion of bilateral internal carotid arteries--case report.

A 45-year-old female presented with blurred vision, headache, and abnormal thirstiness. She was not pregnant nor postpartum. She had diabetes insipidus and bitemporal hemianopsia. Radiological evidence suggested a mass arising in the sella turcica with extension into the parasellar and suprasellar regions. Carotid angiography showed occlusions of bilateral internal carotid arteries at the cavernous portions. The mass was subtotally removed by the trans-sphenoidal approach and was histologically diagnosed as an adenohypophysitis. Laboratory data showed the patient to be in an active state of autoimmune disorder and hypopituitarism. When a patient presents with pituitary insufficiency and an enhanced intrasellar mass lesion on computed tomographic scan, lymphocytic adenohypophysitis must be included in the differential diagnosis.

Autoimmune Diseases↗

PubMed1990

[Ruptured cerebral aneurysm associated with coarctation of the aorta].

We present a 33-year-old female who had a ruptured aneurysm at the trifurcation of the right middle cerebral artery accompanied by coarctation of the aorta. The aneurysm was successfully clipped 15 hours after the attack of subarachnoid hemorrhage and approximately 3 months later the coarctation was surgically treated. Many authors reported that the incidence of cerebral aneurysm was higher in the patients with coarctation than the general population. Our review of the literatures, however, revealed that the incidence of cerebral aneurysm was the same in the population with or without coarctation. The incidence of rupture was higher when the aneurysms was accompanied by coarctation. The average age of the patients at the aneurysmal rupture was younger in the patients with coarctation than the patients without coarctation. These findings suggested that the growth and rupture of aneurysm in the patient with coarctation are related to the hypertension and atherosclerosis. Treatment of the patients with intracranial ruptured aneurysm accompanied by coarctation should begin with the clipping of the aneurysm, and then the coarctation surgically repaired. If the aneurysm is unruptured coarctation should be repaired first, and then the aneurysm clipped.

Adult↗

PubMed1990

[Single drug chemotherapy with 5-FU oral administration of bladder cancer].

58-year-old male with bladder cancer complicated acute myocardial infarction (aMI) were treated by 5-FU 300 mg/day orally for approximately one and a half months as single drug chemotherapy preoperatively. CT studies showed PR in bladder lesion and an improvement of bilateral hydronephrosis also. Biochemical evaluations as Thymidylate synthase inhibition and FdUMP were made on biopsy and operative specimens of urinary bladder. Clinical trials with 5-FU oral administration in bladder cancer were not held widely. Although its effectiveness and safety has been accepted in several fields. It was useful for a conservative operation case as single drug chemotherapy.

Administration, Oral↗

PubMed1990

[Two siblings with interstitial deletion of chromosome 14 [46 XX, del (14) (q12 q13.3)]].

Two siblings with interstitial deletion of chromosome 14 not associated with ring formation were reported. Clinical features of the patients included failure to thrive, severe mental retardation, microcephaly, round face, hypertelorism, micrognathia and high-arched palate. They were common also in five previously reported cases. Other peculiar finding was hyperthyrotropinemia in their neonatal periods; mild hypothyroidism was found in the elder sister, and hyperthyrotropinemia was only transient in the younger sister. By a high-resolution G-banding analysis, the maternal origin of the chromosome with the deletion was noted.

Abnormalities, Multiple↗

PubMed1989

First crystallization of a phosphoenolpyruvate carboxylase from Escherichia coli.

Two different forms of crystal for a phosphoenolpyruvate carboxylase from Escherichia coli were obtained by the hanging-drop vapor diffusion technique, using polyethylene glycol 4000 as precipitant. The hexagonal crystal in space group P6(2)22 (or P6(4)22) has cell dimensions of a = 131 A and c = 325 A, whereas the orthorhombic crystal in space group I222 has a = 119 A, b = 252 A and c = 83 A. A tetrameric molecule (396,244 Mr), a subunit of which contains 883 amino residues, has a crystallographic 2 symmetry in the hexagonal crystal or 222 symmetry in the orthorhombic crystal, respectively.

Carboxy-Lyases↗

PubMed1989

Preliminary X-ray crystallographic study of lysozyme produced by Streptomyces globisporus.

Lysozyme from Streptomyces globisporus has been crystallized in a form suitable for X-ray structure analysis using ammonium sulfate as a precipitant. The crystals are hexagonal, space group P6(1)22 (P6(5)22) with unit cell dimensions: a = b = 129 A, c = 143 A. There are three or four molecules per asymmetric unit. The crystals diffract X-rays to at least 3.0 A resolution.

Muramidase↗

PubMed1989

Stress-induced anorexia in rats mediated by serotonergic mechanisms in the hypothalamus.

The effects of stress on food intake and on neural activity in the lateral hypothalamic area (LHA) were investigated. Significant reduction of daily food intake was observed after 2 hr immobilization. The reduction of body weight was also significant during experimental days. Duplicate injections of methysergide (5 mg/kg, IP) antagonized the immobilization-induced anorexia for 3 hr and injection of naloxone had no effect. Single neuron activity was recorded from a chronically implanted electrode. Activity of 80% of LHA neurons was significantly decreased by immobilization stress. Methysergide significantly attenuated the suppressive effect of immobilization. Further, direct effects of 5-HT on LHA neurons were examined in anesthetized rats. Of 43 LHA neurons tested, the activity of 35 was inhibited by electrophoretic application of 5-HT. These results suggest that immobilization-induced anorexia is mediated at least in part through serotonergic mechanisms in the LHA.

Animals↗

PubMed1989

Lymphocytic adenohypophysitis: report of two cases.

Two women with lymphocytic adenohypophysitis not related to pregnancy are reported on. In obtaining a differential diagnosis of lymphocytic adenohypophysitis preoperatively, it is useful to note swelling of the anterior hypophyseal tissue and the existence of a posterior pituitary lobe on sagittal sections of magnetic resonance imaging scans. Hypofunction of the anterior hypophyseal gland is more severe in lymphocytic adenohypophysitis than in pituitary adenomas. Marked adhesion of fibrotic pituitary capsule to the dura is a characteristic observation during surgery for lymphocytic adenohypophysitis.

Adenoma↗

PubMed1989

Central action of acidic fibroblast growth factor in feeding regulation.

A phasic increase in activity similar to that of acidic fibroblast growth factor (aFGF) was detected in the cerebrospinal fluid of rats after feeding or after an intraperitoneal injection of glucose. This FGF-like activity in the cerebrospinal fluid was bioassayed in two systems: depression of the feeding response of Hydra and DNA synthesis-stimulating activity in BALB/c 3T3 cells after fractionation on a heparin affinity column. Dynamic feeding-related changes in activity of aFGF, basic FGF, and other growth factors were detected by both bioassay systems. Intracerebroventricular microinfusion of aFGF suppressed food intake in rats. Central infusion of inactivated aFGF, or peripheral administration of aFGF, in doses equivalent to or higher than those administered centrally was without effect. Electrophoretically applied aFGF specifically suppressed the activity of glucose-sensitive neurons in the lateral hypothalamus. Glucose-insensitive neurons were only slightly affected. The results suggest that aFGF may participate in the regulation of feeding at the level of the central nervous system.

Animals↗

PubMed1989

[Clinical studies of subcapsular orchiectomy with an intracapsular testicular prosthesis--improving the quality of life in patients with prostatic cancer].

Twenty-five patients termed the method group, having a carcinoma of the prostate, underwent a subcapsular orchiectomy, followed by the placement of an intracapsular prosthesis for anti-androgen treatment. In tandem, a control group of 16 patients, having a carcinoma of the prostate underwent, a total orchiectomy. Further, a histological study of a testicular capsula was performed on an autopsy specimen, but almost no seminiferous residue was detected. Postoperatively, serum testosterone levels decreased to less than 10% of their Preoperative levels, and remained at this level for 30 months. Similar results were obtained in both the method group and the control group postoperative questionnaires showed that the method group experienced less mental and physical stress than did the control group. In a society composed largely of elderly people, this type of operation can be very beneficial to those suffering from prostate carcinoma in maintaining the quality of their lives.

Aged↗

PubMed1989

[Change on the cell proliferation kinetics of the central and peripheral regions of DMBA induced hamster tongue cancer following irradiation].

Cellular changes on the vascular and peripheral sides of DMBA-induced cancer of the tongue in hamsters, were assessed by [3H] thymidine cellular labelling, one and three days after irradiation by 60Co-gamma ray at 20 Gy. The results obtained were as follows: 1) Initial labelling index (L.I.) was high on the vascular side and low on the peripheral side before irradiation. The L.I. on the day following irradiation was decreased was decreased for the whole tumor. The vascular side demonstrated a decrease of about 43% while there were no changes on the peripheral side. This tendency was still observed 3 days after irradiation. 2) Mitosis index (M.I.) were high on the vascular side, and low on the peripheral side before irradiation. On the following day, and three days after irradiation the M.I. was decreased totally, although the decrease was only slight on the vascular side. On the peripheral side, in contrast, the M.I. was increased to about two-fold. 3) There was no difference in the time of cellular rotation (Tc), between vascular and peripheral sides before irradiation, but the Tc on the following day of irradiation was increased by about 3 on both the vascular and peripheral sides of the tumors. In contrast, at three days after irradiation, it was decreased by about 6.5h. 4) There was no difference in the time of preparation for mitosis (Tg2) between the vascular and peripheral sides before irradiation. It was increased by about 2h on both sides on the day following irradiation, and it was increased by about 3h, 3 days after irradiation. 5) Although there was no difference in the time of mitosis (Tm) between both sides, on the day following irradiation, it was increased by about 1.6 times, and 2.1 times, on the vascular and peripheral sides, respectively. A very similar tendency was observed even 3 days after irradiation. 6) There was no difference in the time of DNA synthesis (Ts) between the vascular and peripheral sides of the tumors before irradiation, or at one, or three days after irradiation. 7) Although there was no difference in the time of preparation for synthesis (Tg1), between both sides before irradiation, or on the day following irradiation, it showed a marked decrease of about 90% on both sides of the tumors 3 days after irradiation.

9,10-Dimethyl-1,2-benzanthracene↗