Biomedical subjects

Y Sakai

Publications and source records attributed to Y Sakai.

At least 397 records · Page 22Linked to original sources

PubMed1996

Biochemical characterization of a new disintegrin, flavostatin, isolated from Trimeresurus flavoviridis venom.

We biochemically characterized a new disintegrin, flavostatin, isolated from Trimeresurus flavoviridis venom. Flavostatin inhibited ADP-, collagen-, and thrombin receptor agonist peptide-induced platelet aggregation in human platelet-rich plasma (IC50 range: 59 to 111 nM) and blocked the binding of biotinylated human fibrinogen to purified GPIIb/IIIa with an inhibitory potency 31,000-fold higher than that of Arg-Gly-Asp-Ser (RGDS). Flavostatin strongly inhibited high-shear-stress-induced platelet aggregation in platelet-rich plasma (PRP) with an IC50 value of 188 nM. Fluorescein isothiocyanate (FITC)-conjugated flavostatin saturably bound to unstimulated and ADP-stimulated washed platelets with high affinity (Kd values: 38 and 21 nM, respectively); the corresponding number of binding sites was 86460 and 79192 per platelet. In competition experiments with several glycoprotein IIb/IIIa antagonists, the binding of FITC-conjugated flavostatin to platelets was completely inhibited by ReoPro, triflavin, TP9201, MK383 and GR144053, but not by YM207, YM337 and B6A3.

Amino Acid Sequence↗

PubMed1996

Comparison of the antiplatelet agent potential of the whole molecule, F(ab)2 and Fab fragments of humanized anti-GPIIb/IIIa monoclonal antibody in monkeys.

1. The potential antiplatelet agent use of the whole molecule, F(ab)2 and Fab fragments of humanized antiglycoprotein (GP) IIb/IIIa monoclonal antibody, hC4G1, were investigated in rhesus monkeys. 2. Fab completely inhibited platelet aggregation 1 hr after an i.v. bolus administration of 1 mg/kg without a decrease in platelet count or prolongation of bleeding time, and the duration of inhibition was much shorter than that of F(ab)2. 3. These results suggest that the Fab fragment of hC4G1 may be a more useful antiplatelet agent in patients with acute thromboembolic diseases than the whole molecule or F(ab)2 fragments.

Animals↗

PubMed1996

Clinical observation of spontaneous anginal attacks and multivessel spasm in variant angina pectoris with normal coronary arteries: evaluation by 24-hour 12-lead electrocardiography with computer analysis.

OBJECTIVES: Using a new, computerized 24-h 12-lead electrocardiographic (ECG) recording and analysis system (the EAGLE system), we sought to evaluate the clinical manifestations of ischemic episodes in patients with variant angina and normal coronary arteries. BACKGROUND: Although the prognosis of variant angina without significant organic stenosis is generally good, the incidence of multivessel spasm, a major prognostic factor, is surprisingly high in provocation tests. METHODS: A total of 122 patients with suspected variant or unstable angina underwent 24-h examination with the EAGLE system and two-channel Holter monitoring. Thirty patients in this group were diagnosed as having variant angina with normal or nearly normal coronary arteries. Twenty-two (73%) of these 30 patients developed anginal attacks with ST segment elevation during monitoring and were enrolled in the study. RESULTS: The 22 patients had a total of 138 episodes of transient ST segment elevation and 13 episodes of ST segment depression. No arrhythmias were observed during ST segment depression, but 26 episodes of ST segment elevation (19%) were associated with arrhythmias: 7 with premature ventricular contractions, 3 with ventricular bigeminy, 3 with complete atrioventricular (AV) block, 1 with complete AV block and couplets of premature ventricular contractions and 12 with marked sinus bradycardia (< 45 beats/min). Ten (45%) of the 22 patients had multivessel spasm. We observed three different patterns of multivessel spasm: 1) spasm at a different site on different occasions (migratory spasm); 2) spasm that sequentially affected two different sites; 3) simultaneous spasm at more than one site. The duration of ST segment elevation was much longer in patients with sequential and simultaneous spasm than in those with single-vessel spasm, and arrhythmias were more frequent during these two types of multivessel spasm. CONCLUSIONS: Although the prognosis of multivessel spasm is believed to be poor, this may not necessarily be so. Anginal attacks due to sequential and simultaneous multivessel spasm seem to be more dangerous than those involving single-vessel spasm or migratory multivessel spasm.

Aged↗

PubMed1996

Endoscopic excision of large capsulated lipomas.

The technique of endoscopic excision of large capsulated lipomas is presented and the versatility of this method is discussed based on our clinical experience. We have applied this new technique in 6 cases. In all cases the lipoma was completely removed in one piece through a single incision, up to 1.5 cm in length. The endoscope made it possible to view the lipoma through a narrow space with a wide range of vision on a TV monitor. We stress that this method is not only appropriate as treatment for benign lipomas but also effective from a cosmetic point of view. The applications of the endoscope should widen in plastic surgery when the advantages of it are recognized and new operative approaches for using it are developed.

Adult↗

PubMed1996

Peroral insertion techniques of self-expanding metal stents for malignant gastric outlet and duodenal stenoses.

Self-expanding metal stents (EMS) have gained widespread popularity for the palliative treatment of various stenoses in blood vessels, biliary ducts, bronchi, and the gastrointestinal tract. Regarding stenoses of the upper gastrointestinal tract, EMS insertion for gastric outlet and duodenal stenoses is considerably more difficult than for esophageal stenoses. We describe a reliable EMS insertion technique for malignant gastric outlet and duodenal stenoses.

Aged↗

PubMed1996

Non-peptidic inhibitors of human neutrophil elastase: the design and synthesis of sulfonanilide-containing inhibitors.

A novel series of pivaloyloxy benzene derivatives has been identified as potent and selective human neutrophil elastase (HNE) inhibitors. Convergent syntheses were developed in order to identify the inhibitors which are intravenously effective in an animal model. A compound of particular interest is the sulfonanilide-containing analogues. Structure-activity relationships are discussed. Structural requirements for metabolic stabilization are also discussed.

Aniline Compounds↗

PubMed1996

Follicle stimulating hormone-beta subunit gene is expressed in parallel with a transcription factor Ad4BP/SF-1 in human pituitary adenomas.

OBJECTIVES: A transcription factor Ad4BP/SF-1 is implicated in the differentiation of gonadotrophs in the pituitary gland, but it is not known whether human pituitary cells express this factor. The present study aimed to disclose (1) whether human pituitary adenomas express Ad4BP/SF-1, and (2) if this is the case, what kinds of adenoma express the factor. MATERIAL: Total RNA was extracted from 23 pituitary adenomas obtained by transsphenoidal surgery, and subjected to Northern blot analyses using cDNAs of bovine Ad4BP/SF-1, porcine FSH-beta, LH-beta and glycoprotein hormone-alpha (GPH-alpha) subunts as radiolabelled probes. These adenomas included 13 clinically non-functioning adenomas, 1 GH/PRL-producing adenoma, 6 GH-producing adenomas, 2 PRL-producing adenomas and 1 ACTH-producing adenoma. RESULTS: The expression of Ad4BP/SF-1 exactly coincided with the expression of FSH-beta. Thus 5 out of 13 clinically non-functioning adenomas expressed Ad4BP/SF-1 and only these 5 adenomas expressed FSH-beta. Interestingly, only one of the GH-producing adenomas also expressed Ad4BP/SF-1 as well as FSH-beta. GPH-alpha was expressed in 4 non-functioning adenomas and 2 hormonally functioning adenomas, but did not necessarily coincide with Ad4BP/SF-1 expression. None of the 23 adenomas we tested expressed LH-beta, probably because LH-beta-producing adenomas are rather rare. CONCLUSIONS: The expression of FSH-beta was parallel with Ad4BP/SF-1 expression, indicating that the expression of Ad4BP/SF-1 is restricted to cells derived from gonadotroph lineages in human pituitary adenomas.

Adenoma↗

PubMed1996

Initiation of Sendai virus multiplication from transfected cDNA or RNA with negative or positive sense.

BACKGROUND: The mononegavirus superfamily (Mononegavirales) comprises three families, Rhabdoviridae, Paramyxoviridae and Filoviridae. These viruses possess a single stranded negative sense RNA as the genome. Recent success in the recovery of infectious virus from a transfected cDNA of mononegaviruses including Sendai virus, a prototypic paramyxovirus, is opening the possibility of their genetic engineering. However, infectious viruses have been recovered only by initiating the infectious cycle with cDNA directing the synthesis of antigenomic positive sense (+)RNA. Starting with genomic negative sense (-)RNA has been unsuccessful. Furthermore, the recovery efficiency has often been extremely low. RESULTS: We describe here an analogous system that allows recovery of Sendai virus at a high rate, from cells in which the transfected cDNA and plasmids to support the synthesis of viral nucleocapsid protein and RNA polymerases are coexpressed by vaccinia virus-driven bacteriophage T7 polymerase. Our system was able to recover the virus from cDNA directing not only (+)RNA but also (-)RNA. Moreover, using this system, we succeeded in recovery of the virus by transfection of in vitro synthesized (+)RNA or (-)RNA. This improved virus recovery appeared to be accomplished by supplying the supporting plasmids at an optimal ratio and by minimizing the cytopathic effect of the vaccinia virus by specific inhibitors. In addition, it was probably critical that our cDNAs were constructed to generate viral authentic RNAs without adding T7 promoter-specific nucleotides to the 5' ends. An immediate application of the system was demonstrated by the creation of a candidate vaccine strain with a predetermined attenuating mutation in the cleavage-activation site of the viral fusion glycoprotein. CONCLUSION: We have established methods which greatly improve the recovery of Sendai virus from cDNA. There is essentially no absolute obstacle to recovery of the virus from the (-)RNA template. Even the complete full length RNA chain in the naked form appears to be properly encapsidated to become a functional template.

Amino Acid Sequence↗

PubMed1996

Intestinal fatty acid-binding protein is a useful diagnostic marker for mesenteric infarction in humans.

BACKGROUND & AIMS: Acute ischemic diseases of the small bowel are lethal emergencies with no reliable diagnostic biochemical tests available. Experimental studies have suggested rat intestinal fatty acid-binding protein (I-FABP) as a serum marker reflecting bowel ischemia; the present study evaluates the human homologue (human I-FABP) as a serum marker for the diagnosis of acute ischemic diseases of the bowel. METHODS: Enzyme immunoassay was applied to determine I-FABP levels in the sera of 96 subjects: 13 preoperative patients with ischemic bowel diseases (5 cases of mesenteric infarction and 8 cases of strangulated obstruction of the small bowel), 35 healthy subjects, and 48 hospitalized patients with acute abdominal pain. RESULTS: Serum I-FABP levels were < 65 ng/mL in healthy subjects. In patients with acute abdominal pain, levels ranged from < 20 to 87 ng/mL (mean, 27.4 ng/mL), not significantly different from findings in healthy subjects. However, patients with ischemic bowel disease showed significantly higher I-FABP levels, ranging from < 20 to 1496 ng/mL (mean, 265.8 ng/mL). All 5 patients with mesenteric infarction showed I-FABP levels of > 100 ng/mL. CONCLUSIONS: I-FABP is a useful biochemical marker for the accurate diagnosis of mesenteric infarction.

Adolescent↗

PubMed1996

Primary gastrointestinal T-cell lymphoma resembling multiple lymphomatous polyposis.

An extremely rare case of primary gastrointestinal T-cell lymphoma involving the stomach and intestine is reported. Radiographic and endoscopic examinations showed multiple polypoid lesions covered by a normal-appearing mucosa in the stomach, duodenal bulb, and terminal ileum and numerous small aphthoid lesions throughout the entire colorectum. Histopathologic, immunohistochemical, and polymerase chain reaction studies were performed using paraffin-embedded or fresh-frozen specimens from endoscopic biopsies and endoscopic mucosal resections. All lesions were composed of small, atypical lymphoid cells, which were classified as low-grade pleomorphic lymphoma. The tumor cells expressed CD3, CD4, and the T-cell receptor gamma gene phenotype as well as human mucosal lymphocyte 1 antigen, suggesting that the lymphoma cells were derived from intraepithelial T lymphocytes. This is the first description of primary gastrointestinal T-cell lymphoma with expression of human mucosal lymphocyte 1 antigen and a novel morphology resembling multiple lymphomatous polyposis.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1996

The absence of Pmp47, a putative yeast peroxisomal transporter, causes a defect in transport and folding of a specific matrix enzyme.

Candida boidinii Pmp47, an integral peroxisomal membrane protein, belongs to a family of mitochondrial solute transporters (e.g., ATP/ADP exchanger), and is the only known peroxisomal member of this family. However, its physiological and biochemical functions have been unrevealed because of the difficulties in the molecular genetics of C. boidinii. In this study, we first isolated the PMP47 gene, which was the single gene encoding for Pmp47 in a gene-engineerable strain S2 of C. boidinii. Sequence analysis revealed that it was very similar to PMP47A and PMP47B genes from a polyploidal C. Boidinii strain (ATCC32195). Next, the PMP47 gene was disrupted and the disruption strain (pmp47delta) was analyzed. Depletion of PMP47 from strain S2 resulted in a retarded growth on oleate and a complete loss of growth on methanol. Both growth substrates require peroxisomal metabolism. EM observations revealed the presence of peroxisomes in methanol- and oleate-induced cells of pmp47delta, but in reduced numbers, and the presence of material of high electron density in the cytoplasm in both cases. Methanol-induced cells of pmp47delta were investigated in detail. The activity of one of the methanol-induced peroxisome matrix enzymes, dihydroxyacetone synthase (DHAS), was not detected in pmp47delta. Further biochemical and immunocytochemical experiments revealed that the DHAS protein aggregated in the cytoplasm as an inclusion body, while two other peroxisome matrix enzymes, alcohol oxidase (AOD) and catalase, were active and found in peroxisomes. Two peroxisome-deficient mutants, strains M6 and M13 (described in previous studies), retained DHAS activity although it was mislocalized to the cytoplasm and the nucleus. We disrupted PMP47 in these peroxisome-deficient mutants. In both strains, M6-pmp47delta and M13-pmp47delta, DHAS was enzymatically active and was located in the cytoplasm and the nucleus. We suggest that an unknown small molecule, which PMP47 transports, is necessary for the folding or the translocation machinery of DHAS within peroxisomes. Pmp47 does not catalyze folding directly because active DHAS is observed in the M6-pmp47delta and M13-pmp47delta strains. Since both AOD and DHAS have the PTS1 motif sequences at their carboxyl terminal, our results first show that depletion of Pmp47 could dissect the peroxisomal import pathway (PTS1 pathway) of these proteins.

Alcohol Oxidoreductases↗

PubMed1996

New method of endoscopic pterygomaxillary disjunction for a Le Fort Type I osteotomy.

Endoscopic pterygomaxillary (PM) disjunction in a Le Fort type I osteotomy is presented, and the versatility of this new technique is discussed on the basis of our own experience. We have reexamined the anatomy of the posterior part of the maxilla, focusing in particular on the neurovascular bundle, to attempt to perform the endoscopic PM disjunction through the maxillary sinus along a new osteotomy line. We found that the use of an endoscope provided a magnified field of vision and a view of the objects being manipulated on a television monitor, thereby reducing the necessity of working blind. We have applied this technique in 10 clinical cases, and in all cases the Le Fort type I osteotomy was accomplished safely and with minimal bleeding. The operative time using an endoscope was about 15 minutes to 20 minutes on each side, and the blood loss during this manipulation was less than 50 mL. The application of the endoscope should widen in craniofacial surgical field when its advantages are recognized and new operative approaches for using it are developed.

Adolescent↗

PubMed1996

Endoscopic facial skeletal surgery using a neuronavigator.

In the reconstruction of asymmetrical deformities of the facial skeleton, both an endoscope and a neuronavigator have been used. The endoscope allows the surgeon a wide view of the object on a television monitor, reduces the scarring, minimizes the undermined field, and reduces the need to work blind. The neuronavigator is a frameless computed tomographic stereotactic device that has been mainly used in neurosurgery. The device is easy to use and can offer the surgeon three-dimensional coordinates of the status during the operation. We have used this new technique in three clinical cases, two involving augmentation of the zygomatic bone on one side and one involving reduction of the frontal bone on one side. The surgical techniques we used and the versatility of both the endoscope and the neuronavigator are discussed herein based on our own experience.

Adolescent↗

PubMed1996

Early detection of platelet activation after coronary angioplasty.

BACKGROUND: Although platelet activation has been considered an important reaction after percutaneous transluminal coronary angioplasty (PTCA), it is still difficult to detect the activated platelets in vivo directly. METHODS: To detect platelets activated at an early stage after PTCA, blood samples were take from the coronary sinus and the aorta in 22 patients with coronary artery disease, who underwent PTCA for a lesion of the left anterior descending artery. Ten patients with coronary artery disease, who underwent diagnostic coronary angiography only, were compared with them. The expression of activation-dependent granular protein, CD62P (P-selectin) and CD63, on the platelet membrane surface was analysed using flow cytometry. The plasma thrombomodulin level was also measured. RESULTS: The percentage of platelets positive for CD62P (0.53 +/- 0.04 to 0.80 +/- 0.11%, P < 0.01) and CD63 (16.0 +/- 1.4 to 19.8 +/- 2.0%, P < 0.05) increased after PTCA in the coronary sinus, although it did not change in the aorta. The plasma thrombomodulin level also increased after PTCA in the coronary sinus (16.7 +/- 1.0 to 20.4 +/- 2.0 mu/ml, P < 0.05). However, these parameters did not change after coronary angiography only. After PTCA, the plasma thrombomodulin level was correlated with the percentage of platelets positive for CD62P (r = 0.88, P < 0.001) and with that for CD63 (r = 0.69, P < 0.001) in the coronary sinus. CONCLUSIONS: PTCA produced activation of circulatory platelets, which might have been caused by balloon-induced vascular endothelial injury. One should take care to avoid needless vascular injury during the PTCA procedure to inhibit the platelet activation.

Angioplasty, Balloon, Coronary↗

PubMed1996

Rescue of Sendai virus cDNA templates with cDNA clones expressing parainfluenza virus type 3 N, P and L proteins.

Several years ago, we reported that a Sendai virus (SeV) defective genome (DIH4UV) could be rescued in vivo with human parainfluenza virus type 1 (hPIV1) and bovine PIV3 but not by measles virus or vesicular stomatitis virus. It was concluded that the cis-acting RNA sequences were conserved within the SeV/PIV1/PIV3 group but that interactions between the polymerase complex (P-L) and the template protein N were unique for each virus. We have re-examined these conclusions using proteins expressed from cloned N, P and L genes for SeV and PIV3. The results demonstrate the specificity of the protein-protein interactions between polymerase and template, and confirm the prediction of the earlier work that PIV3 N, P and L proteins are capable of assembling and replicating SeV mini-genomes also expressed from a cDNA clone.

Animals↗

PubMed1996

Detection of hepatocellular carcinoma after interferon therapy for chronic hepatitis C: clinical study of 26 cases.

The clinical findings in 26 patients in whom hepatocellular carcinoma (HCC) was detected after the start of interferon (IFN) therapy for chronic hepatitis C were analysed. Histological study before IFN therapy showed that 34.6% of patients were categorized as stage 3 (septal fibrosis with architectural distortion; the 0-4 scale) and 80.8% demonstrated at least some evidence of septal fibrosis or more advanced features. The AFP levels examined before IFN therapy were more than 20 ng/mL in 13 patients (84.6% of those studied). One of 26 patients had a complete response to IFN therapy, while six of 26 patients had only a partial response. HCC was detected within 1 year after the start of IFN therapy in 76.9% of patients. Thus, the possibility of the early occurrence of HCC or its existence at the time of therapy should be seriously considered when IFN therapy is contemplated. Patients with stage 3 or 3-4 histology may already have a small undetectable HCC before IFN therapy. Thus, for this reason, every patient treated with IFN should be examined at short regular intervals for the development of HCC during and after IFN therapy.

Adult↗

PubMed1996

Functional stability of porcine hepatocyte spheroids in various culture systems under 100% porcine and human plasma conditions.

To select an immobilization method suitable for bioartificial liver (BAL) modules utilizing porcine hepatocyte spheroids, functional activities were compared in various systems in 100% porcine and human plasma together with a synthesized medium. The spheroids, continuously suspended in rotating dishes or entrapped in collagen (CN) gel, expressed approximately two times higher ammonium detoxification abilities over conventional monolayers during 8 days of direct contact with 100% human or porcine plasma with a standardized inoculum cell number. No significant deterioration was observed in the abilities as compared with that in a synthesized medium. Although the cell number gradually decreased in rotational culture, the abilities per cells remaining on Day 10 were two times higher than in the CN-gel entrapped spheroids in all the media examined, presumably due to the diffusion limitation by the gel. Thus, in utilizing porcine hepatocyte spheroids in BAL modules, immobilization allowing direct contact of spheroids with perfused patient plasma was concluded to be possible and suitable.

Animals↗

PubMed1996

Oral mucosal lesions in experimental graft-versus-host disease: morphological and immunohistochemical characterization of infiltrating cells.

To facilitate recognition of the oral mucosal lesion that develops in rats with graft-versus-host disease (GVHD) induced by injecting spleen cells of parental strain rats (Brown Norway) into non-irradiated (Brown Norway x Lewis) F1 hybrid rats, we followed the development of the tongue lesion histologically and immunohistochemically. This assessment revealed an increase in the number of MHC class II+ cells with dendritic shape in the lamina propria to be the earliest stage of the tongue lesions in GVHD rats. The subsequent mononuclear cell infiltration with epithelial cell destruction, characteristic of GVHD, consisted of CD8+ cells and macrophages. Our findings seem to indicate that MHC class II+ cells with dendritic shape may provide antigen presentation in the induction of local immunological responses, including tissue destruction, by CD8+ cells and macrophages in the tongue of GVHD rats.

Animals↗