Biomedical subjects

Y Kai

Publications and source records attributed to Y Kai.

At least 127 records · Page 7Linked to original sources

PubMed1994

Crystallization and preliminary X-ray diffraction studies of curculin. A new type of sweet protein having taste-modifying action.

A taste-modifying protein, curculin, has been crystallized by the vapor diffusion method using polyethylene glycol 400 as a precipitant. The crystals belong to orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions: a = 105 A, b = 271 A, c = 48.7 A. The crystals diffract X-rays to at least a resolution of 3.0 A and are suitable for X-ray crystallographic studies.

Crystallization↗

PubMed1994

Epidermal growth factor--induced implantation and decidualization in the rat.

Effects of epidermal growth factor (EGF) on blastocyst implantation and experimentally-induced decidualization were examined in the rat. Intraluminal injection of EGF into each uterine horn induced implantation in the ovariectomized progesterone-treated delayed implanting rat in a dose-dependent manner. This induction was inhibited by indomethacin, an inhibitor of prostaglandin synthesis. Intraluminal injection of EGF on day 5 of pseudopregnancy elicited a greater decidual response when compared to the vehicle-injected contralateral uterine horn. These results suggest that EGF may play important roles in the process of implantation and decidualization in the rat.

Animals↗

PubMed1994

Structure of azurin from Achromobacter xylosoxidans NCIB11015 at 2.5 A resolution.

The crystal structure of azurin from a denitrifying bacterium, Achromobacter xylosoxidans NCIB11015, has been refined at 2.5 A resolution using diffraction data obtained by means of synchrotron radiation at KEK. Crystals suitable for X-ray experiment were obtained by the macro-seeding method and an intensity data were obtained on imaging plates mounted on a Weissenberg camera (Rmerge = 0.09). The initial model was obtained by the molecular replacement method using the structure of azurin from Alcaligenes denitrificans NCTC8582 as a starting model. The structure was refined by molecular dynamics optimization and the restrained least-squares method to a crystallographic R-value of 0.205. However, the current model gave an electron-density of the side-chain regions of several residues close to the N-terminus quite different from those expected from the amino acid sequences reported. Very recently, two kinds of azurins (Az-I and Az-II) were isolated from this bacterium by a slightly modified purification method and have been characterized and found to have different CD spectra. On analysis of amino acid sequences around the N-terminus, the second azurin (Az-II) was proved to be a new type of azurin in this bacterium. It was consequently revealed that the current model corresponds to a new type of azurin because of the complete agreement between the electron-density and the amino acid sequence of the newly determined 20 residues from the N-terminus. Determination of the whole amino acid sequence of this azurin and further refinement are in progress.

Alcaligenes↗

PubMed1994

Enhancement by propofol of the gamma-aminobutyric acidA response in dissociated hippocampal pyramidal neurons of the rat.

BACKGROUND: Activation of the gamma-aminobutyric acidA (GABAA) receptor-ionophore complex has been reported as a possible molecular mechanism of the anesthetic action of propofol. Augmentation of GABA-induced inhibitory transmission has also been suggested as a mechanism. Because data describing this latter mechanism in mammalian neurons are few, we have examined the effects of propofol on the GABA response in central neurons of the rat. METHODS: Hippocampal pyramidal neurons were dissociated after enzyme treatment of the rat brain slices. The neurons were voltage-clamped with the whole cell configuration of the patch clamp technique. Neurotransmitters and drugs were applied using the "Y-tube" method, which exchanges the extracellular solutions around the neuron within 10-20 ms and makes it possible to obtain the peak response before desensitization develops. RESULTS: In pyramidal neurons voltage-clamped at -60 mV, GABA induced an inward current. Propofol (10(-6) M) augmented the current and shifted the concentration-response curve for GABA to the left without affecting the maximum response. A low concentration of the anesthetic (10(-6) M) reduced the dissociation constant for GABA from 8.2 x 10(-6) to 4.2 x 10(-6) M without a significant effect on the Hill coefficient. Coapplication of propofol at a higher concentration (5 x 10(-6) M) also shifted the GABA dose-response curve to the left, reducing the dissociation constant to 2.8 x 10(-6) M. Potentiation by propofol was not associated with a change in the reversal potential for the GABA response and was not voltage-dependent. The inhibitory glycine response was not affected by propofol (10(-6) M or 5 x 10(-6) M). CONCLUSIONS: Propofol at clinically relevant concentrations enhances the inhibitory GABAA receptor-mediated response in mammalian central neurons. The enhancement may result in reduced excitability of the neuronal network and may, consequently, contribute to the anesthetic action of the agent.

Animals↗

PubMed1994

Targeted chemotherapy for unresectable primary and metastatic liver cancer.

In targeted chemotherapy, Lipiodol Ultrafluid was used as a carrier of anticancer drugs; these combinations were termed oily anticancer agents. Arterial injection therapy with these oily anticancer agents was performed in 330 patients with unresectable hepatocellular carcinoma (HCC) and 110 patients with unresectable metastatic liver cancer. The alpha-fetoprotein (AFP) level decreased in 178 of 186 AFP-positive patients with HCC. Tumor size was reduced in 256 of 269 evaluable patients with HCC. The treatment seemed to prolong survival and in 193 HCC patients who were good candidates for therapy (those without Child C liver cirrhosis, without tumor occupying all four segments of the liver, or without extrahepatic spread) the 1-, 2-, and 5-year survival rates were 85, 52, and 34% respectively. In the 110 patients with metastatic liver cancer, the carcinoembryonic antigen level and tumor size were reduced. The 1-, 2-, and 5-year survival rates of these 110 patients were 61, 32, and 22% respectively.

Aclarubicin↗

PubMed1994

[Studies on skin irritation with urostomy--the gross and histologic evaluation of the attached area with urostomy].

The degree of damage on the peristomal skin of 42 patients who accepted the urostomy was visually and histologically evaluated. The incidence of damages on the areas of the skin where the materials was applied was 85.7%. The occurrence of non-active lesions (mainly permanent pigment change) was statistically more significant than the active lesions (mainly redness) [p < 0.05]. The incidence of skin lesions using the skin barrier agents was significantly lower statistically than the incidence with the adhesive medication indicating a superior treatment for the skin condition [p < 0.05]. Although the gross appearances were normal, the microscopic and electron microscopic evaluations detected chronic damages indicating comparatively evident changes. The results suggest that these histological evaluations are useful in examining the damage on peristomal skin.

Adult↗

PubMed1994

[Influence of anti-androgen therapy for prostatic hypertrophy on lipid metabolism].

Antiandrogen therapy has an important role in the treatment of patients with benign prostatic hypertrophy who lack indication for surgery. Herein, the effects on lipid metabolism of administration of antiandrogen agents for benign prostatic hypertrophy are reported. Eighty patients with benign prostatic hypertrophy were each treated with the antiandrogen agents, chlormadinone acetate, allylestrenol, gestonolone caproate and oxendolone for 12 months. The levels of total cholesterol (TC), triglyceride (TG), high density lipoprotein (HDL), low density lipoprotein (LDL), alpha-lipoprotein, apoprotein, and maronediardehyde (MDA) were measured every 4 weeks after initiation of antiandrogen treatment. In the chlormadinone acetate group, the TG level was significantly decreased between 3 and 6 months after treatment (p < 0.05). In the oxendolone group, the alpha-lipoprotein level was also elevated between 3 and 6 months and between 6 to 12 months after treatment (p < 0.05). The MDA level was also significantly elevated 6 and 12 months after treatment. However, the levels of the other lipids were within the normal range. In conclusion, the changes in the levels of plasma lipoprotein, apoprotein and MDA resulting from antiandrogen therapy were unlikely to be a cause of ischemic coronary disease.

Aged↗

PubMed1994

[A resected case of pulmonary plasma cell granuloma infiltrating the pericardium].

The patient was a 66-year-old man. An abnormal mass on his chest X-ray was pointed out during a regular check-up in November 1991. He was admitted to our hospital with the chief complaint of productive cough in January 1992. With the diagnosis of lung cancer, right middle and lower lobectomy with lymph node resection and partial resection of the pericardium was carried out. The pathological examination revealed pulmonary plasma cell granuloma infiltrating the pericardium. Postoperative course was uneventful. No recurrence was seen 17 months after operation. As pulmonary plasma cell granuloma is histologically benign, this was a very rare case with extra-pulmonary extension. Up to present, only 8 cases including this case has been reported in the literature. We reviewed these 8 cases.

Aged↗

PubMed1994

[A case of transitional cell carcinoma of the prostate].

A 46-year-old man was admitted to our hospital with the complaint of gross hematuria and renal failure. The patient had undergone right nephrectomy 10 years earlier suffering from nephrotuberculosis, and the remaining left side manifested severe hydronephrosis and vesicoureteral reflux (VUR). After the immediate nephrostomy, renal function was recovered and hematuria was improved preservatively. By the rectal examination, a goose egg size and stony hard prostate was detected. The needle biopsy of the prostate revealed pathologically transitional cell carcinoma (TCC) G2, and the image findings showed stage of T4N0M0 of the prostatic carcinoma. Modified pelvic exenteration was performed, and specimens were examined by the step section method. The diagnosis was TCC, G2 > G3 and stage of pT4N0 in the right lobe of the prostate. This case is she 20th reported case in Japan. We emphasize the importance of the mapping of dissected specimens and the reviewed literature.

Carcinoma, Transitional Cell↗

PubMed1994

[A case report of posterior urethral polyp in a child].

The urethral polyps in children are different from those in adults because the polyps usually originate at the proximal vermontanum, and are covered with transitional epithelium. A case of posterior urethral polyp in a child is reported herein. In this case, 5 years of age, the polyp was thought to be the cause of urinary tract infection (UTI) and histological findings revealed fibrous non-prostatic tissue. Transurethral resection of polyp was performed successfully.

Child↗

PubMed1994

[Mixed angioma of the brain: report of two cases].

Clinical features of two patients with mixed angiomas are presented. One patient with a cerebral venous angioma with arterial components was successfully treated with radiation therapy; and the other, who had a common draining vein with cerebellar arteriovenous malformation and venous angioma, was treated with surgical removal of the arteriovenous malformation. These two cases suggested that there is a similarity between the pathogenesis of arteriovenous malformation and venous angioma in the brain.

Adult↗

PubMed1993

[The consideration and performing of pretesting of contrast medium: surveying in Kanagawa].

The pretesting of contrast medium is world widely recognized to be an invaluable method to predict the adverse reactions. It was still required to perform on patients who shall have a contrast examination until recently in Japan. In May of 1990 the contrast drug package insert was reviewed and a statement of "there is no known method to predict the adverse reactions" was included. Although two reports suggested that the percentage of not performing the pretesting was increasing gradually since then, the clinical communications between institutes did not support the truth. This study investigated the problem by surveying the area in Kanagawa-ken neighboring to Tokyo and revealed that: 1. The percentage of non-performing the pretesting is high in radiologist and urologist (both are 40%) but low in other physicians (18%). 2. The risky performances of pretesting in the area without emergent equipment are occurring daily. 3. The percentage of the approval to abandon the pretesting increased significantly (from 46% to 89% with p < 0.01) after the accurate information on pretesting was given. 4. To prevent the tragedy caused by risky performance, actively contacting with and offering the information are necessary.

Contrast Media↗

PubMed1993

Crystallization and preliminary X-ray studies of a protease from Pseudomonas aeruginosa.

A protease produced by Pseudomonas aeruginosa has been crystallized by the vapor-diffusion method using polyethylene glycol 4000 as a precipitant. The crystals belong to the hexagonal space group P6(1) (P6(5) with unit cell dimensions; a = b = 106.9 A, c = 96.9 A. There are two molecules per asymmetric unit. The crystals diffract X-rays to at least 3.0 A and are suitable for X-ray crystallographic studies.

Crystallization↗

PubMed1993

Crystallization and preliminary X-ray studies on pseudoazurin from Achromobacter cycloclastes IAM1013.

New crystals of a blue copper protein, pseudoazurin from denitrifier Achromobacter cycloclastes IAM1013, have been obtained by means of vapor diffusion with ammonium sulfate as a precipitant at pH 6.0 and 4 degrees C. The crystals belong to the orthorhombic system, space group P2(1)2(1)2(1), with unit cell dimensions of a = 56.69(2), b = 61.53(2), and c = 30.20(1) A. The asymmetric unit includes one molecule of pseudoazurin with a Vm value of 2.04 A3/Da. The crystals are so stable against X-ray irradiation that a complete data set up to 1.54 A has been collected using a single native crystal. Solution of the structure was performed by means of the Patterson search techniques, and the current crystallographic R-factor is 17.5% at 3.0 A resolution. Refinement at higher resolution is in progress.

Alcaligenes↗

PubMed1993

Propofol activates GABAA receptor-chloride ionophore complex in dissociated hippocampal pyramidal neurons of the rat.

BACKGROUND: The molecular mechanism of propofol anesthesia has been related to facilitation of the inhibitory neurotransmission mediated by gamma-aminobutyric acid (GABA). In the current study, the authors examined the direct actions of propofol on the acutely dissociated mammalian central neurons. METHODS: Hippocampal pyramidal neurons were dissociated after enzymatic treatment of the brain slices of the rat. Single neurons were voltage-clamped using the whole cell configuration of the patch clamp technique, and drugs were applied with a rapid drug-application system. RESULTS: In the pyramidal neurons voltage-clamped at -60 mV, propofol evoked a transmembrane inward current, which desensitized at high concentrations of the anesthetic. The peak amplitude of the current increased sigmoidally with increasing doses of propofol applied. A least-squares fitting gave a dissociation constant of 1.2 x 10(-5) M and a Hill coefficient of 1.8, thereby indicating that clinical concentrations of propofol evoke the current, and that the anesthetic cooperatively activates the channel. The threshold concentration was less than 10(-6) M. The reversal potential for the current shifted according to the chloride equilibrium potential predicted by the Nernst equation, indicating that the current was carried by chloride ions. Bicuculline and strychnine suppressed the current in a concentration-dependent manner, in which the former was almost 40-fold more potent than the latter. The propofol-induced current cross-desensitized with the GABA-induced current, but no such interaction was observed with the glycine-induced current. Ro15-1788 (10(-6) M), an allosteric benzodiazepine antagonist, had no effect on the response. Diazepam (10(-6) M) enhanced the propofol-induced current, but pentobarbital (10(-6) M and 3 x 10(-5) M) did not affect the current. CONCLUSIONS: Propofol at clinically relevant concentrations directly activates the GABAA receptor-chloride ionophore complex in the mammalian central neurons and, hence, increases the chloride conductance, which may contribute to anesthesia produced by the agent. The desensitization of the GABAA receptor in the presence of high concentrations of propofol may result in a suppression of the GABAA inhibitory system.

Animals↗

PubMed1993

Use of sciatic neurogenic motor evoked potentials versus spinal potentials to predict early-onset neurologic deficits when intervention is still possible during overdistraction.

Spinal evoked potentials, sciatic neurogenic motor evoked potentials, and somatosensory evoked potentials were recorded before and after overdistraction of the spinal cord, and compared with the clinical status of 14 pigs. The sciatic neurogenic motor evoked potential consisted of two components: fast and slow. The fast component was more sensitive and associated to a greater degree with motor function in wake-up tests than the slow component somatosensory evoked potential and spinal evoked potential. Furthermore, the loss of only the fast component in the initial status allowed the possibility of improvement of motor activity in the final wake-up test. The peripheral neurogenic motor evoked potentials recording yielded more information about spinal cord function: motor and sensory. The current study suggests that a peripheral response is a better index to the onset of overdistraction and to the efficiency of intervention, when the neurologic deficit after overdistraction of the spine is reversible.

Animals↗

PubMed1993

[Evaluation of bladder tumor staging by submucosonography].

Submucosonography to stage tumors of the esophagus and stomach is well reported. Here we report our experience with a modified procedure to evaluate the stage of bladder tumor cystoscopically and compare the results of staging by other methods. The evaluation was carried out on accuracy 10 patients (10 bladder tumors). A water soluble contrast medium (CM: lohexol 33 mg/ml) was injected into the submucosa of the bladder cystoscopically. Usually the injected point was one centimeter to the urethral margin of the tumor and up to three points were selected. Within 30 minutes after the injection, the lateral and frontal X-ray pictures were taken. The accuracies of staging by submucosonography were compared with the results of other methods, i.g., ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI). By submucosonography, three categories depending on the diffusion of CM were classified as follows. Type I: (diffuse type) without disturbance of diffusion. Type II: (borderline type) between type I and III. Type III: (defect type) local disturbance of diffusion. Overall accuracies of each were 70.0% (submucosonography), 62.5% (US), 44.4% (CT), 66.7% (MRI) respectively. The accuracies of submucosonography were high in stage Ta, above stage T2 and low in stage T1.

Adult↗

PubMed1993

Aneurysm of the right gastroepiploic artery: a case report of laparoscopic resection.

A traumatic pseudoaneurysm of the right gastroepiploic artery in a 55-year-old woman was resected using laparoscopy. The durations of anaesthesia and operation were 260 and 220 min respectively. Blood loss was minimal. The perioperative period was uneventful; the patient needed no analgesic treatment and ate her first meal on the morning of the day after surgery. She was discharged 5 days later and has progressed well for 5 months since surgery without any abnormal findings.

Abdominal Injuries↗