Biomedical subjects

R Yamada

Publications and source records attributed to R Yamada.

At least 91 records · Page 5Linked to original sources

PubMed1999

The effect of cyclic AMP on expression of the major immediate-early genes and replication of human cytomegalovirus in human central nervous system cell lines.

The effect of dibutyryl cyclic AMP (dbcAMP) on interaction of human cytomegalovirus (HCMV) with human central nervous system cell lines was examined. Activation of the major immediate-early (IE) promoter (MIEP) of HCMV by dbcAMP was observed in human neuroblastoma IMR-32 cells, but not in glioma 118MGC and astrocytoma U373-MG cells. The 19 bp repeat element in the enhancer of the MIEP was most likely to be the cis-element that responded to dbcAMP in IMR-32 cells as we expected. In IMR-32 cells activation of the MIEP led to enhanced synthesis of the major IE proteins and infectious HCMV.

Astrocytoma↗

PubMed1999

Antibiotic-induced endotoxemia in a patient with endogenous endophthalmitis.

PURPOSE: The aim of the study is to describe a case of suspected endotoxin-induced uveitis associated with septic endogenous endophthalmitis followed by antibiotic-induced endotoxemia. METHODS: The human leukocyte antigen (HLA) typing of peripheral leukocytes was studied by lymphocytotoxicity technique. Histological and immunohistochemical studies of paraffin embedded specimen were conducted. RESULTS: Findings of HLA typing revealed positive reaction for B 51, Cw 3, DR 8, DR 11, DQ 3. The vitreous body of an eviscerated eye was occupied by the non-specific granulomatous tissue, composed of fibroblast, plasma cells, and Sudan black staining positive foamy cells, including melaniferous phagocytes, identified as CD 68 positive macrophage. CONCLUSION: It is suggested that antibiotic-induced endotoxemia of a patient with septic endogenous endophthalmitis produced endotoxin-induced uveitis under an upregulation of HLA and endotoxin activated macrophages may release cytokines, followed by fibrin formation and subsequent granuloma.

Aged↗

PubMed1999

The effect of head posture on direction and stability of mandibular closing movement.

This study investigated the effects of head posture on mandibular habitual closing movement. Ten healthy subjects were examined. Head posture was evaluated as a sagittally viewed inclination of the head, and was changed from 25 degrees forward bending up to 30 degrees backward bending in 5 degrees increments. The mandibular opening and closing movement was measured at each head posture. As the head bended forward, the closing path approached the maximum intercuspal position from the anterior region, and as the head was bent backward, the closing path approached the maximum intercuspal position from the posterior region. However, the limit of this relationship was found when the head was bent forward to some extent. There was also a correlation between the head posture and the stability of the closing movement. The forward bending of the head decreased the stability of the closing path, and conversely, the backward bending increased the stability of the closing path. It was concluded that the head posture affects the direction and stability of the mandibular closing movement. Possible underlying reasons for these findings are masticatory muscle activity and the tension and resistance of inframandibular soft tissue varying with the change of head posture.

Adolescent↗

PubMed1999

A multimedia intervention on cardiopulmonary resuscitation and advance directives.

OBJECTIVE: To assess the effects of a multimedia educational intervention about advance directives (ADs) and cardiopulmonary resuscitation (CPR) on the knowledge, attitude and activity toward ADs and life-sustaining treatments of elderly veterans. DESIGN: Prospective randomized controlled, single blind study of educational interventions. SETTING: General medicine clinic of a university-affiliated Veterans Affairs Medical Center (VAMC). PARTICIPANTS: One hundred seventeen Veterans, 70 years of age or older, deemed able to make medical care decisions. INTERVENTION: The control group (n = 55) received a handout about ADs in use at the VAMC. The experimental group (n = 62) received the same handout, with an additional handout describing procedural aspects and outcomes of CPR, and they watched a videotape about ADs. MEASUREMENTS AND MAIN RESULTS: Patients' attitudes and actions toward ADs, CPR and life-sustaining treatments were recorded before the intervention, after it, and 2 to 4 weeks after the intervention through self-administered questionnaires. Only 27.8% of subjects stated that they knew what an AD is in the preintervention questionnaire. This proportion improved in both the experimental and control (87.2% experimental, 52.5% control) subject groups, but stated knowledge of what an AD is was higher in the experimental group (odds ratio = 6.18, p <.001) and this effect, although diminished, persisted in the follow-up questionnaire (OR = 3.92, p =. 003). Prior to any intervention, 15% of subjects correctly estimated the likelihood of survival after CPR. This improved after the intervention in the experimental group (OR = 4.27, p =.004), but did not persist at follow-up. In the postintervention questionnaire, few subjects in either group stated that they discussed CPR or ADs with their physician on that day (OR = 0.97, p = NS). CONCLUSION: We developed a convenient means of educating elderly male patients regarding CPR and advance directives that improved short-term knowledge but did not stimulate advance care planning.

Advance Directives↗

PubMed1999

Low-dose succinylcholine facilitates laryngeal mask airway insertion during thiopental anaesthesia.

We have assessed the optimal dose of succinylcholine to provide satisfactory conditions for insertion of a laryngeal mask airway (LMA) without causing myalgia during induction of anaesthesia with thiopental. We studied 60 adult patients, allocated randomly to one of three groups: group 1 (n = 20) received normal saline, group 2 (n = 20) received succinylcholine 0.25 mg kg-1 and group 3 (n = 20) received succinylcholine 0.5 mg kg-1. Insertion of the LMA was performed 1 min after administration of succinylcholine or saline. Insertion conditions were significantly better in group 3 compared with groups 1 and 2. The incidence of adverse responses on insertion was significantly higher in groups 1 and 2 than in group 3. Four of 20 patients (20%) in group 3 complained of myalgia, which was higher than that in group 1 (0%) and group 2 (10%), but there were no significant differences between groups on the day of operation. On day 3 after operation, seven patients (35%) in group 3 complained of myalgia, which was significantly higher than that in group 1 (5%) and group 2 (20%). Time from administration of succinylcholine to resumption of spontaneous respiration was significantly longer in groups 2 (194.9 (SD 50.4) s) and 3 (234.2 (34.3) s) than in group 1 (84.7 (32.4) s). There was also a significant difference between groups 3 and 2 for duration of apnoea.

Adult↗

PubMed1999

Inhibitory effects of of L-2'-deoxyguanosine 5'-triphosphate (L-dGTP) and L-2'-deoxythymidine 5'-triphosphate (L-dTTP) on human telomerase.

Telomerase, which synthesizes telomeric DNA in eukaryotic cells, is classified as a reverse transcriptase. To clarify the recognition of 2'-deoxyribonucleoside 5'-triphosphate (dNTP) chirality by telomerase, we studied the inhibitory effects of L-dGTP on HeLa cell telomerase activity using a quantitative 'stretch PCR' assay. L-dGTP had a weakly inhibitory effect (IC50 = 200 microM) in the presence of 10 microM dGTP. This effect was less obvious when the concentration of dGTP was higher. L-dTTP had a similar inhibitory effect. These findings suggest that telomerase may bind to L-dGTP and L-dTTP, and that the ability of telomerase to bind to dGTP or dTTP is changed.

Base Sequence↗

PubMed1999

Hepatic microcirculatory changes induced by hepatic artery embolization in rats: original investigation.

RATIONALE AND OBJECTIVES: To evaluate the effects of hepatic artery embolization (HAE), hepatic microcirculatory changes induced by HAE were assessed quantitatively in rats. METHODS: Using in vivo microscopy, the blood-flow velocity (BFV) through terminal portal venules (TPVs) and terminal hepatic venules (THVs) was measured during HAE with gelatin sponge powder (GSP), iodized oil (Lipiodol, 0.1, 0.2, and 0.4 mL/kg), or 0.1 mL/kg Lipiodol followed by GSP. RESULTS: After HAE with GSP, BFV through TPVs decreased significantly, but BFV through THVs did not decrease. After HAE with Lipiodol (0.2 and 0.4 mL/kg), BFV through TPVs decreased significantly, but BFV through THVs did not. After HAE with Lipiodol followed by GSP, BFV through both TPVs and THVs decreased significantly. CONCLUSIONS: Neither GSP nor Lipiodol adversely affects hepatic microcirculation when administered alone; however, HAE with a combination of Lipiodol and GSP does adversely affect hepatic microcirculation.

Animals↗

PubMed1999

Behaviour of urinary dipeptidase in patients with chronic renal failure.

Renal dipeptidase (EC 3.4.13.19) activity in serum and urine from healthy volunteers (n = 20), patients with diabetes (n = 18) and patients with chronic renal failure (n = 5) was measured using glycyl-D-alanine as substrate. The assay was highly specific for the enzyme and was not affected by the various aminopeptidases present in serum and urine. No difference in serum renal dipeptidase activity was observed between the groups. The enzyme activity (U/L) in urine was higher than that in serum, irrespective of the group, suggesting the urine concentration was not affected by the serum concentration. The mean renal dipeptidase activities in urine were 2.56, 2.46 and 0.78 U/mol creatinine for healthy subjects, patients with diabetes and patients with chronic renal failure, respectively. The renal dipeptidase activity was significantly lower in the chronic renal failure group. The urinary excretion of dipeptidase (U/mmol creatinine) showed significant inverse correlations with that of beta 2-microglobulin, albumin and alpha 1-microglobulin, and with serum concentrations of creatinine, beta 2-microglobulin and alpha 1-microglobulin. We suggest that urine dipeptidase may be a useful marker of renal diseases.

Adult↗

PubMed1999

[Medulloblastoma originating in the pons].

Medulloblastoma usually originates in the cerebellum. We report here a case of medulloblastoma originating in the pons. Pontine medulloblastoma is extremely rare, with only one report in the literature. An 11-year-old girl was admitted to our hospital with vertigo. Magnetic resonance imaging (MRI) revealed a tumor originating in the pons. On the 4th day after admission, the tumor bled. Because the patient's life was in danger from brain herniation, hematoma removal and tumor resection were carried out. The diagnosis was medulloblastoma. After surgery, the patient received radiation therapy and chemotherapy. Unlike tumors originating in the cerebellum, this tumor did not seem to be effectively reduced by these therapies. Radiation therapy and chemotherapy may not be effective for medulloblastoma originating in the pons. We considered it necessary to make a histological diagnosis even though the tumor originated in the pons and resection was difficult technically.

Brain Neoplasms↗

PubMed1999

[Means of effective and practical intra-arterial chemotherapy for locally invasive bladder cancer--with special reference to clinical analysis of bladder cancer patients treated by intermittent intra-arterial infusion using an implantable port system].

Fifty-six patients with locally invasive bladder cancer were treated by chemotherapy with intermittent arterial infusion from an implanted reservoir and alteration of intrapelvic blood flow. The tip of an infusion catheter was inserted selectively into an internal iliac artery by an angiographic technique. Superior gluteal artery and the other internal iliac artery were then embolized with steel coils so that the drugs would perfuse throughout the tumor through a single catheter. Treatment consisted of intermittent injection of cisplatin (10 mg/body) and doxorubicin (10 mg/body) or epirubicin (10 mg/body) or pirarubicin (10 mg/body) in a ten-minute period every week (for the first 8 weeks) or every two weeks (after the 8th week). Fifty patients were objectively evaluated and the response rate was 80%. The overall survival rate in 54 patients at 1, 3, 5 and 8 years was 83.7%, 61.2%, 52.6%, and 52.6%. The 1-, 2-, 3-, 5- and 7-year disease free survival rate in evaluable 22 patients who showed a complete response (CR) was 91.8%, 85.2%, 65.6%, 58.3% and 58.3%. No serious side effects, such as severe myelosuppression or renal and/or liver dysfunction, were noted during treatment. These findings suggest that intermittent arterial chemotherapy with an implanted reservoir is clinically useful. This procedure appears safe and is easily performed in the outpatient clinic for the treatment of locally advanced bladder cancer.

Adult↗

PubMed1999

[Invasive thymoma associated with pure red cell aplasia and liver metastasis: a case report].

A case of invasive thymoma associated with pure red cell aplasia and liver metastasis was reported. A 57-year-old male was admitted to our hospital because of hepatic abnormal shadow on computed tomography. Malignant tumor was suspected by imaging procedures. Left lateral segmental resection of liver was performed and histo-pathological examination proved the tumor to be liver metastasis of thymoma. He was received 50 Gy irradiation after incomplete resection of thymoma. In the course of time he contracted pure red cell aplasia. But he is well controlled medically and alive 7 years after the surgery.

Humans↗

PubMed1999

[Blood flow velocity in the central retinal artery of exotoxin-induced uveitis in rabbits].

PURPOSE: Exotoxin-induced uveitis in rabbit eyes was established by intravitreal inoculation of staphylococcal enterotoxin B (SEB). Association between findings of pulsed Doppler assessments and histological features were evaluated. MATERIAL AND METHODS: Eyes of rabbits were unilaterally inoculated with 50 ng/kg of intravitreal SEB. Pupil diameter, blood flow velocity in the central retinal artery in both eyes and heart rate were measured using an ultrasonic diagnostic apparatus after inoculation. RESULTS: The pupil diameter and the mean blood flow velocity in central retinal arteries decreased and reached a trough 3-5 hours after the inoculation, then increased. Pulsatility index showed reciprocal fluctuations. Histological features at the early phase after inoculation revealed lymphocytic, plasmacytic, and polynuclear leukocytic infiltrations around the anterior chamber, limbal conjunctivae, ciliary body, and nerve fiber layer of the retina, followed by recovery after about 5 days. At the late phase, recurrent inflammations in the ciliary body and intravitreal space were observed in addition to invasion into the rod and cone layer. CONCLUSION: Early and late phase uveitis was established by intravitreal SEB. It is considered that the uveitis may be caused by two different regulatory mechanisms.

Animals↗

PubMed1999

Intraspinal extradural cysts communicating with adjacent herniated disks: imaging characteristics and possible pathogenesis.

We report two cases of intraspinal extradural cysts communicating with an adjacent herniated disk that we term "disk cysts." These cysts were well defined and homogeneous, and were present in the ventrolateral extradural space adjacent to a lumbar herniated disk. They had rim enhancement on contrast-enhanced MR images, and communication with a herniated disk was revealed by diskography.

Adult↗

PubMed1998

Biosynthesis of D-aspartate in mammalian cells.

In this communication, we demonstrate that D-aspartate (D-Asp) is synthesized in pheochromocytoma cells (PC12). To our knowledge this is the first report of biosynthesis of D-Asp in mammalian cells. Synthesis of D-Asp was demonstrated by its time-dependent accumulation in the cell culture, and by the fact that this accumulation was proportional to the number of inoculated cells. D-Asp in PC12 cells was identified by (i) co-elution with authentic D-Asp on two different HPLC columns, an octadesyl silica column and a Pirkle-type chiral column, (ii) reversed elution order of D-Asp and L-Asp on another Pirkle-type chiral column with an opposite configuration, and (iii) sensitivity to D-Asp oxidase. In the cells the amount of D-Asp was approx. 12-14% of total Asp and no other investigated D-amino acid was detected. The amount of D-Asp did not increase during the culture of mouse 3T3 fibroblasts and human neuroblastoma NB-1 cells. Immunocytochemical staining with anti-D-Asp antiserum demonstrated that D-Asp synthesized is present in the cytoplasm of the cells.

3T3 Cells↗

PubMed1998

Peroxisomal localization of D-aspartate oxidase and development of peroxisomes in the yeast Cryptococcus humicolus UJ1 grown on D-aspartate.

The peroxisomal localization of D-aspartate oxidase (EC. 1.4.3.1) was demonstrated in the yeast Cryptococcus humicolus UJ1 cells grown in the medium containing D-aspartate as a nitrogen source. The conclusion is based on the identical behavior of the enzyme with those of peroxisomal marker enzymes, catalase and urate oxidase, during all steps of subcellular fractionations. Supporting evidence was provided by the morphometric analysis of the peroxisomes with electron microscopy, showing that the cells grown on D-aspartate contained more and larger peroxisomes than those grown on L-aspartate, consistent with the 500-fold and 3-fold, higher contents of D-aspartate oxidase and catalase activities, respectively, in the former cells than the latter.

Amino Acid Oxidoreductases↗

PubMed1998

The expression and localization of fibroblast growth factor-1 (FGF-1) and FGF receptor-1 (FGFR-1) in human breast cancer.

Fibroblast growth factor-1 (FGF-1) is an inducer of angiogenesis, the growth of new blood vessels. The expression and localization of FGF-1 (acidic FGF) and FGF receptor (FGFR)-1 in mammary tissues from patients with breast cancer was investigated using Western blot analysis and immunohistochemistry. The affinity-purified FGF-1 antibody which did not have cross-reactivity to FGF-2 (basic FGF) was used in this study. Western blot analysis demonstrated the presence of FGF-1 protein in all of the samples from breast cancer, but not benign tumors such as mastopathy and fibroadenoma. To assess the localization of FGF-1 in cancer tissues, immunostaining with specific antibody was performed. All samples from breast cancer displayed significantly intense staining with FGF-1 antibody. The extent and intensity of immunoreactive FGF-1 polypeptides in cancer cells was statistically much greater than those of cells from fibroadenoma or mastopathy. Control immunostaining with normal rabbit serum or anti-FGF-1 antibody adsorbed with the recombinant FGF-1 polypeptide was completely negative. In contrast to FGF-1, Western blot analysis demonstrated the presence of FGFR-1 protein in all of the samples from breast cancer and benign tumors. By immunohistochemical analysis, the enhanced expression of FGFR-1 was observed in breast cancer cells. Benign tumor cells or interstitial cells displayed a faint expression of FGFR-1. These results demonstrated that breast cancer cells not only generated FGF-1, but also expressed FGFR-1, and FGF-1 might play a role in the proliferation of breast cancer cells not only by paracrine but also by autocrine mechanism.

Adult↗

PubMed1998

D-amino acid hydrolysing enzymes.

Only a few enzymes that hydrolyse peptide bonds involving D-amino acids effectively have been discovered and characterised in multicellular organisms. Mammalian renal dipeptidase hydrolyses various dipeptides with a D-amino acid only at the C-terminal with similar efficiency to their L-amino acid diastereomers, but not dipeptides with an N-terminal D-amino acid residue. Nor does the enzyme act on tripeptides. Dipeptides similar to those hydrolysed by the enzyme are also hydrolysed by cytosolic leucine aminopeptidase, but much less effectively than their L-amino acid diastereomers. Peptidyl-D-amino acid hydrolase from cephalopods has a somewhat broader substrate specificity than the renal dipeptidase and hydrolyses, as well, some dipeptides with a D-amino acid at the N-terminal. It also acts on larger peptides than dipeptides, albeit slowly. Carnosinase is specific to dipeptides containing L-His as the C-terminal residue, and hydrolyses D-Ala-L-His about as well as carnosine.

Amino Acids↗

PubMed1998

Occurrence of free D-aspartate and aspartate racemase in the blood shell Scapharca broughtonii.

Substantial concentrations of D-aspartate were found in several tissues of Scapharca broughtonii together with approximately equal concentrations of L-aspartate. The foot and mantle extracts also contained an aspartate racemase activity. The formation of L-aspartate from the D-enantiomer by the foot extract was apparently slower than the reverse reaction, and this unbalance seemed to be due to the presence of an enzyme activity which rapidly converted L-aspartate to L-alanine. The possible role of D-aspartate in the anaerobiosis was discussed.

Amino Acid Isomerases↗