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Biomedical subjects

A Sato

Publications and source records attributed to A Sato.

At least 307 records · Page 17Linked to original sources
PubMed1998

Influence of oocyte preincubation time on fertilization after intracytoplasmic sperm injection.

During the intracytoplasmic sperm injection (ICSI) procedure, the collected oocytes are incubated until just before ICSI. The ideal preincubation time of oocytes was investigated in 544 treatment cycles. Oocyte retrieval was carried out 35 h after human chorionic gonadotrophin administration. Oocytes were cultured for between 1 and 11 h before ICSI. Embryo transfer was performed 48 h after oocyte collection. The survival, fertilization and cleavage rates of injected oocytes indicated no statistically significant differences between oocytes preincubated for different lengths of time. The proportion of good-quality embryos (grades 1 and 2) was lower at 9-11 h of preincubation time than for all the other preincubation times (P < 0.001). No statistically significant differences were detected in the pregnancy rate between each group (mean: 15.9%), although the pregnancy rate at 9-11 h of preincubation time appeared to be low (7.7%). These results suggest that the oocyte retained sufficient potential for fertilization between 1 and 9 h after oocyte collection in ICSI. For the researchers who practise more complex ICSI procedures than IVF, it would be convenient to be able to perform ICSI at any time between 1 and 9 h after oocyte collection.

Adult↗
PubMed1998

Characterization of TEK receptor tyrosine kinase and its ligands, Angiopoietins, in human hematopoietic progenitor cells.

TEK, or TIE-2, is a receptor tyrosine kinase (RTK) that is known as a functioning molecule of vascular endothelial cells. TEK comprises a subfamily of RTK with TIE, and these two receptors play critical roles in vascular maturation, maintenance of integrity and remodeling. We generated mAb against the extracellular domain of human TEK protein to elucidate its expression pattern in human hematopoietic cells. Flow cytometric analysis of bone marrow cells revealed that TEK was expressed in 27% of CD34+ cells, 20% of c-KIT+ cells and 26% of CD34+CD38- cells, indicating that TEK is expressed in a subset of primitive hematopoietic stem cells (HSC). TEK was also expressed in 20% of CD19+ B lymphocytes but not in other lineage-committed cells. Progenitor assays in methylcellulose culture showed that CD34+TEK+ cells formed significantly less BFU-E and CFU-Mix than CD34+TEK- cells, but there was no difference in the number of CFU-GM between these two populations. Two recently identified TEK ligands, termed Angiopoietin-1 and -2, bound to TEK with similar affinities, and Angiopoietin-1 effectively induced TEK phosphorylation in hematopoietic cells. Angiopoietin-2 also induced a low level of TEK phosphorylation and weakened the phosphorylation induced by Angiopoietin-1, suggestive of an elaborate regulator of the TEK-TEK ligand signaling pathway. Although neither ligands affected the proliferation of TEK-transfected hematopoietic cells or the colony formation of CD34+TEK+ bone marrow cells, both promoted the adhesion of TEK-transfected hematopoietic cells to a collagen matrix or a layer of bone marrow stromal cells. These findings indicate that the TEK-TEK ligand signaling pathway is regulated in a refined manner and is involved in hematopoietic cell-microenvironment interaction.

Angiopoietin-1↗
PubMed1998

Influence of alcohol on branched-chain amino acid/tyrosine molar ratio in patients with cirrhosis.

We investigated whether the reduction of plasma tyrosine in alcoholic liver disease would affect the branched-chain amino acid/tyrosine molar ratio (BTR) measured using an enzymatic assay method in alcoholic cirrhosis. BTR values were higher in patients with compensated and decompensated alcoholic cirrhosis (5.68 +/- 2.29 and 3.28 +/- 0.75) due to reduction of the tyrosine level relative to those in patients with nonalcoholic cirrhosis (3.64 +/- 1.22 and 2.53 +/- 0.99). A decrease in tyrosine level and an increase in BTR value were observed after single ethanol administration to healthy subjects. As significant elevation of serum immunoreactive insulin levels followed elevation of serum glucose levels after alcohol loading, it was thought that insulin accelerated intrahepatic metabolism of aromatic amino acids, resulting in reduction of the tyrosine level. The same mechanism may be applied to tyrosine reduction in patients with alcoholic cirrhosis during heavy drinking.

Adult↗
PubMed1998

Construction of the chimeric reverse transcriptase of simian immunodeficiency virus sensitive to nonnucleoside reverse transcriptase inhibitor.

A number of structurally diverse compounds have been shown to be potent inhibitors of the DNA polymerase activity of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT). The compounds can be grouped into two broad classes; nucleoside analogs and nonnucleoside RT inhibitors. The nonnucleoside RT inhibitors are quite specific for HIV-1 RT but not human immunodeficiency virus type 2 (HIV-2) and simian immunodeficiency virus (SIV) RT. We have investigated the property of SIV/HIV-1 chimeric viruses in which portions of SIV(MAC) RT were exchanged with the corresponding domain of HIV-1 RT; amino acids 176-190, 176-383 and 176-495 of HIV-1 RT. The chimeric virus, which was substituted amino acids 176-190 of RT, had detectable RT activity, and this chimeric RT was sensitive to three nonnucleoside RT inhibitors [nevirapine, HEPT derivative (E-EBU-dM) and TIBO derivative (R82913)]. To further study this chimeric virus, we purified the chimeric RT enzyme expressed in Escherichia coli and determined its kinetic properties; the Km, and Vmax values, and the Ki value of HEPT derivative calculated for the DNA polymerase activity. This study reveals that amino acids 176-190 of SIV(MAC) RT were important for the enzymatic activity and the SIV/HIV-1 chimeric RT, which had amino acids 176-190 of HIV-1, was sensitive to the nonnucleoside RT inhibitor.

Amino Acid Sequence↗
PubMed1998

Oral and epicutaneous desensitization in urushiol contact dermatitis in guinea pigs sensitized by 2 methods of different sensitizing potency.

This investigation was conducted to study the relationship between the different intensities of sensitization to urushiol induced by the maximization test method (MT) or by the ear-flank method (EF) in guinea pigs, and hyposensitization induced by repeated oral and/or epicutaneous administration of the allergen, and to compare the immune tolerance achieved between these routes of dosing. During the observation period of 10 weeks, both oral and epicutaneous administration produced hyposensitization to urushiol after weak sensitization by EF; however, only combined administrations via the oral and epicutaneous routes achieved hyposensitization after potent sensitization, while inadequate tolerance was induced by oral dosing and none by epicutaneous dosing. Thus, it is indicated that difficulty in establishing immune tolerance may increase with increasing intensity of primary sensitization, and that hyposensitizing potency tends to increase in the order epicutaneous, oral and combined (e.p.+p.o.) administrations of urushiol.

Administration, Cutaneous↗
PubMed1998

[A clinical study of pulmonary cryptococcosis. The Study Group of Respiratory Mycosis in Kyoto].

During the 7 years from 1990, thirty-two patients (20 in male and 12 in female, mean age; 53 years old) were diagnosed as having pulmonary cryptococcosis. To clarify the essential points for early diagnosis of pulmonary cryptococcosis, we reviewed the clinical records and chest images. Three patients had a past history of pulmonary tuberculosis and eleven patients had underlying disorders such as malignancy, chronic pulmonary diseases and so on, but no HIV infection, which would affect this disease. Eighteen patients did not have any past history nor complications. The symptoms such as cough, sputum, chest pain and fever were generally of low-grade, 14 patients had no symptom at diagnosis. Except of some patients with severe infections and severe underlying disorders, laboratory findings such as inflamatory and nutritious markers were almost within near the normal range. On plain chest X-ray films the distribution of lesions was almost in proprtion to the volume of the lobes. The multifocal nudular and/or infitrative shadows wer observed in about 2/3 cases and single lesion in about 1/3. The width of lesions were minimal except of one case with interstitial pneumonia and two cases with multifocal segmental pneumonia. The cavity lesions were observed in 7 cases and hilar lymphadenopathy in 3 cases. On CT images, the lesions were almost located in the outer zone, the lesions which were adjacent to the pleura were observed in 15 cases. Cavitary lesions were almost smooth in edge and ubiquitous, the walls were also thick. The peripheral air-bronchogram in the nodular/infitrative shadows were observed in three cases. Pulmonary cryptococcosis is air-borne and almost a chronic infection except in AIDS patients, so careful planning for examination is essential with considerations of the characteristics of clinical and imaging features of this infection.

Adult↗
PubMed1998

[Pulmonary tuberculosis with diabetes mellitus, presenting multiple nodular shadows].

An asymptomatic 52-year-old male, who was diagnosed as poorly controlled diabetes mellitus (DM), was referred to our hospital because of abnormal shadows on chest X-rays. Physical examinations and laboratory data showed no abnormal findings except increased values of blood sugar and HbA1c (12.1%). Chest X-ray and CT scan revealed multiple nodular shadows in both lung fields. The specimens from transbronchial biopsy showed epithelioid granuloma, and Mycobacterium tuberculosis was confirmed with bronchial wash fluid. The patient was then treated with antimycobacterial drugs and sulfonylurea along with diet therapy. The multiple nodular shadows gradually disappeared. It seemed that impaired host defense mechanisms caused by poorly controlled DM is responsible for the bronchogenic dissemination of M. tuberculosis, resulting in the extension into the multiple nodular shadows. Thus, a good control of DM is important for the prevention of an onset and excerbation of tuberculosis in patients with DM.

Diabetes Complications↗
PubMed1998

S-1153 inhibits replication of known drug-resistant strains of human immunodeficiency virus type 1.

S-1153 is a new imidazole compound that inhibits human immunodeficiency virus (HIV) type 1 (HIV-1) replication by acting as a nonnucleoside reverse transcriptase inhibitor (NNRTI). This compound inhibits replication of HIV-1 strains that are resistant to nucleoside and nonnucleoside reverse transcriptase inhibitors. S-1153 has a 50% effective concentration in the range of 0.3 to 7 ng/ml for strains with single amino acid substitutions that cause NNRTI resistance, including the Y181C mutant, and also has potent activity against clinical isolates. The emergence of S-1153-resistant variants is slower than that for nevirapine, and S-1153-resistant variants contained at least two amino acid substitutions, including F227L or L234I. S-1153-resistant variants are still sensitive to the nucleoside reverse transcriptase inhibitors zidovudine (AZT) and lamivudine. In a mouse and MT-4 (human T-cell line) in vivo HIV replication model, S-1153 and AZT administered orally showed a marked synergy for the inhibition of HIV-1 replication. S-1153 shows a significant accumulation in lymph nodes, where most HIV-1 infection is thought to occur. S-1153 may be an appropriate candidate for two-to three-drug combination therapy for HIV infection.

Animals↗
PubMed1998

T-tropic human immunodeficiency virus type 1 (HIV-1)-derived V3 loop peptides directly bind to CXCR-4 and inhibit T-tropic HIV-1 infection.

Certain types of chemokine receptors have been identified as coreceptors for HIV-1 infection. The process of viral entry is initiated by the interaction between an envelope protein gp120 of HIV-1, CD4, and one of the relevant coreceptors. To understand the precise mechanism of the Env-mediated fusion and entry of HIV-1, we examined whether the V3 region of gp120 of T-cell line tropic (T-tropic) virus directly interacts with the coreceptor, CXCR-4, by using five synthetic V3 peptides: two cyclized V3 peptides (V3-BH10 and V3-ELI) which correspond to the V3 regions of the T-tropic HIV-1 IIIB and HIV-1 ELI strains, respectively, a linear V3 peptide (CTR36) corresponding to that of HIV-1 IIIB strain; and cyclized V3 peptides corresponding to that of the macrophage-tropic (M-tropic) HIV-1 ADA strain (V3-ADA) or the dualtropic HIV-1 89.6 strain (V3-89. 6). FACScan analysis with a CXCR-4(+) human B-cell line, JY, showed that V3-BH10, V3-ELI, and V3-89.6 but not CTR36 or V3-ADA blocked the binding of IVR7, an anti-CXCR-4 monoclonal antibody (MAb), to CXCR-4 with different magnitudes in a dose-dependent manner, while none of the V3 peptides influenced binding of an anti-CD19 MAb at all. Next, the effects of the V3 peptides on SDF-1beta-induced transient increases in intracellular Ca2+ were investigated. Three V3 peptides (V3-BH10, V3-ELI, and V3-89.6) prevented Ca2+ mobilization. Furthermore, the three peptides inhibited infection by T-tropic HIV-1 in a dose-dependent manner as revealed by an MTT assay and a reverse transcriptase assay, while the other peptides had no effects. These results present direct evidence that the V3 loop of gp120 of T-tropic HIV-1 can interact with its coreceptor CXCR-4 independently of the V1/V2 regions of gp120 or cellular CD4.

Amino Acid Sequence↗
PubMed1998

Beneficial effects of verapamil on intestinal ischemia and reperfusion injury: pretreatment versus postischemic treatment.

We studied the effect of verapamil on intestinal ischemia and reperfusion (I/R) injury. Intestinal ischemia was induced by clamping the superior mesenteric artery for 30 min followed by reperfusion. Magnetic resonance spectroscopy was employed as a marker of the changes in the energy metabolism. Further, histological changes and the changes of water contents were evaluated. Recovery rates of energy metabolism after intestinal I/R were improved by verapamil, administered before and after ischemia, and tissue edema was significantly reduced with verapamil. These findings suggest that verapamil results in an improved recovery of the energy metabolism and cellular preservation, presumably by reducing the intracellular calcium influx.

Animals↗
PubMed1998

Expression of epidermal growth factor and epidermal growth factor receptor immunoreactivity in the asthmatic human airway.

Chronic airway inflammation, one of the pathophysiologic features of bronchial asthma, is suspected to be responsible for irreversible pathological changes of airways, called airway remodeling. To examine the mechanisms of airway remodeling in asthma, we investigated the expression of epidermal growth factor (EGF) and its receptor immunohistochemically in asthmatic human airways. Airway specimens from seven patients with asthma were obtained from autopsied and surgically resected lungs. Control specimens were obtained from lungs of eight subjects without asthma and other pulmonary complications at autopsy. We stained those specimens by the avidin-biotin-peroxidase complex (ABC) method with anti-human polyclonal EGF antibody and monoclonal EGF receptor antibodies. Three different portions of airways-large bronchi (about 1 cm in diameter), small bronchi (about 3 mm in diameter), and peripheral airways (less than 2 mm in diameter)-were examined. The thickness of the bronchial smooth muscle and basement membrane was significantly greater in the asthmatic airways than in controls. Clear immunoreactivities of EGF were widely observed on bronchial epithelium, glands, and smooth muscle in asthmatic airways. In the controls, the bronchial epithelium and the bronchial glands partially expressed faint EGF immunoreactivity. For the EGF receptor, clear immunoreactivities were also observed on bronchial epithelium, glands, smooth muscle, and basement membrane in asthmatic airways. In control airways, only part of the bronchial epithelium and smooth muscle weakly expressed EGF receptor immunoreactivity. These results suggest a possible contribution of EGF to the pathophysiology of bronchial asthma, including airway remodeling.

Adult↗
PubMed1998

Protein carbonyl content roughly reflects the unsaturation of lipids in muscle but not in other tissues of stroke-prone spontaneously hypertensive strain (SHRSP) rats fed different fats and oils.

We examined in vivo the effect of dietary fats and oils with different peroxidizability on protein carbonyl content, the presumed index of free radical-mediated protein oxidation. For 15.6 months, SHRSP (stroke-prone spontaneously hypertensive strain) rats were fed a diet supplemented with lard, safflower oil, perilla oil or fish oil/soybean oil, the peroxidizability of which increases in this order. The peroxidizability of tissue lipids was positively correlated with the protein carbonyl content in skeletal muscle, but not in the brain, heart or liver. The protein carbonyl content in the lard group was higher in the brain and liver compared to the other dietary groups. These results contradict the concept that long-term feeding of easily autoxidizable fatty acids allows the accumulation of lipid peroxides to accelerate the development of the free radical diseases, and suggest that tissue protein carbonyl content is not a simple reflection of autoxidizability-related lipid peroxidation but is also influenced by other biochemical processes.

Aging↗
PubMed1998

Pathophysiological effects of dietary essential fatty acid balance on neural systems.

Dietary fatty acid balance has been revealed to affect neural functions as well as chronic diseases such as cancer, cerebro- and cardiovascular diseases, and allergic hyper-reactivity. In this review, we focused on the pathophysiological effects of n-6 and n-3 fatty acids on brain functions. Long-term n-3 fatty acid deficiency in the presence of n-6 fatty acids has been shown to affect learning behavior, drug sensitivity and retinal functions. Some membrane enzymes and ion channel functions have been shown in experimental animals to be regulated by membrane fatty acid modifications. We also summarized the effects of these fatty acids in diets on human psychotic aspects and brain diseases. Although biochemical mechanisms remain to be elucidated, investigations on the effect of dietary fatty acids on neural networks may provide an important clue to clarify complex brain functions.

Animals↗
PubMed1998

Peripheral blood stem cell transplantation for hepatoblastoma with microscopical residue: a therapeutic approach for incompletely resected tumor.

We report a nine-month-old boy with stage III B hepatoblastoma of caudate lobe origin. Surgical resection was attempted following six courses of chemotherapy, but viable tumor cells remained microscopically at resection margins. Subsequently, he received peripheral blood stem cell transplantation (PBSCT), whose preparative regimen being consisted of carboplatin, etoposide, tetrahydropyranyl adriamycin, and melphalan. Since then, the patient shows no relevance of local relapse or distant metastasis without any chemotherapy. PBSCT for patients with post-operative residue may improve the outcome of advanced hepatoblastoma and worth of a further clinical investigation.

Disease-Free Survival↗
PubMed1998

Evaluation of immunostaining for MIB1 and nm23 products in uterine cervical adenocarcinoma.

In this study, we evaluated whether proliferative activity and metastatic potential are prognostic factors in adenocarcinoma of the cervix. Formalin-fixed, paraffin-embedded sections from 34 patients with cervical adenocarcinoma or adenosquamous carcinoma were immunostained with monoclonal antibody MIB1, expressed in proliferating cells, and anti-nm23 antibody, reacts with metastasis suppression gene products. MIB1 positivity ranged from 0.2 approximately 54.7% with a mean of 21.4%. The level did not differ significantly between various clinicopathological categories. Although patient survival of high or low MIB1 expressing tumor was not significantly different, the disease-free interval of high (> or =25%) expressing tumor was significantly lower than that of low (<25%) expressing tumor. Strong and medium expression for nm23 were detected in 7 (21%) and 3 (9%) of patients. Tumor with strong nm23 expression tended to have a higher relapse rate. Although the survival of strong and weakly nm23 expressing tumor was not significantly different, the disease-free survival of strong nm23 expressing tumor was lower than that of weakly nm23 expressing tumor. MIB1 and nm23 immunostaining might be some of prognostic indicators of recurrence in cervical adenocarcinoma. In cervical adenocarcinoma, the nm23 gene products may not function as metastatic suppression but reflect proliferative activity.

Adenocarcinoma↗
PubMed1998

Improved survival of children with advanced tumors by myeloablative chemotherapy and autologous peripheral blood stem cell transplantation in complete remission.

Five children with neuroblastoma (NB) stage IV and five children with rhabdomyosarcoma (RMS) stage III were treated with myeloablative chemotherapy and autologous peripheral blood stem cell transplantation (MCT/PBSCT) in the state of complete remission (CR) achieved by conventional therapy. PBSCs were collected in CR status using a cell separator with blood access through a double-lumen central venous catheter. PBSCs with 1.9+/-0.8x10(5) of CFU-GM per patient weights (kg) were infused following MCT after a period of conventional therapy for 11.1+/-2.1 or 9.7+/-0.9 months in NB or RMS patients, respectively. Regimen-related toxicity of MCT was tolerable and peripheral white blood cell count recovered beyond 1.0x10(3)/microl 10-12 days after infusion of PBSCs in all patients. All of RMS patients and three of five NB patients survived for an average of 31.6 months (ranged 10.8-58.1). The survival rate of these patients was improved as compared with our historical controls, and presumably, with that of conventional chemotherapy previously reported. Despite a limited number of patients, it appears that MCT/PBSCT may be effective in improving survival by preventing relapse which may occur thereafter if treated with conventional therapy alone. Furthermore, MCT/PBSCT reduced the duration of treatment, as compared with that of conventional chemo-therapy. Therefore, this study may suggest the feasibility and promise of the therapy including MCT/PBSCT for children with advanced stages of NB and RMS.

Antineoplastic Agents↗
PubMed1998

Diffuse panbronchiolitis and rheumatoid arthritis-associated bronchiolar disease: similarities and differences.

There is a considerable overlap between diffuse panbronchiolitis (DPB) and bronchiolar disease associated with rheumatoid arthritis. The present study assessed how these conditions could be differentiated. The subjects included 25 DPB patients and 15 RA patients with bronchiolar disease (RA-BD). Patients with either condition had chronic cough, purulent sputum, dyspnea and coarse crackles. Most patients with either DPB or RA-BD had a history of sinusitis as well as elevated cold hemagglutin titers and decreased levels in partial pressure of oxygen (PaO2), forced expiratory volume in one second (FEV1.0) and V 25/Ht. On histological examination, both conditions also shared various histological patterns although panbronchiolitis lesions were more common in DPB than RA-BD (68% vs 20%) and bronchiolar obliteration appeared to occur at more proximal sites in RA-BD than DPB. However, there were important differences: long-term treatment with erythromycin had less effect in RA-BD than DPB, and the frequency of HLA B54 tended to be higher in DPB than RA-BD (50.0% vs 22.2%), suggesting that they are distinct conditions.

Adult↗