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Biomedical subjects

H Sakai

Publications and source records attributed to H Sakai.

At least 649 records · Page 36Linked to original sources
PubMed1994

Absence of anti-trifluoroacetate antibody after halothane anaesthesia in patients exhibiting no or mild liver damage.

It has been shown that the circulating antibodies, which bind to rat hepatic microsomal proteins obtained after in vivo exposure to halothane, are detectable by immunoblotting in patients with "halothane hepatitis (HH)," and that rabbit immunized anti-sera against trifluoroacetylated rabbit serum albumin (TFA-RSA) recognizes rat microsomal distorted polypeptides in almost the same way as do sera from patients with HH. In this paper, we report first the development of a novel method of synthesizing TFA-RSA using p-nitrophenyl TFA, and second the results of tests for circulating anti-TFA antibodies in the serum of 86 patients who had received halothane anaesthesia and developed no (67 patients) or mild (19 patients, the maximum activity of serum alanine aminotransaminase 519 IU.L-1) liver damage. Serum was selected from stored sera of post-transfusion patients. The new method of synthesizing TFA-RSA was convenient and was able to be done at neutral pH. Rabbit sera obtained after immunization with the newly synthesized TFA-RSA recognized the same polypeptides (109 kDa, 92 kDa, 80 kDa, 76 kDa, 64 kDa and 59 kDa) as the established anti-sera against TFA-RSA, and these reactions were inhibited in the presence of TFA-lysine. Circulating antibodies were not detected in our patients who had developed no or mild liver damage. The present finding supports the hypothesis that the appearance of circulating antibodies against microsomal distorted proteins are specific to patients with HH. Furthermore, we have shown here that the halothane-induced mild increase in ALT activity is not associated with the appearance of those circulating antibodies, supporting the pathophysiological difference between HH and halothane-induced mild hepatic damage.

Adolescent↗
PubMed1994

Ultrastructure of the neuromuscular junction of vasomotor nerves in the microvasculature of human dental pulp.

Vasomotor nerves in human dental pulp were more closely related to arterioles than to venules. Most were composed of unmyelinated fibres, which were mainly adrenergic. They appeared close to arterioles that were surrounded by a few layers of contractile smooth-muscle cells. The smaller arterioles with a diameter of 10-15 microns received a more intimate innervation by vasomotor nerves than did the larger. These vessels occasionally showed much narrower neuromuscular junctions than previously reported. Most of these nerve fibres were identified as adrenergic by the presence of chromaffin-positive synaptic vesicles detected by ultrastructural enzyme histochemistry. Their function appeared to be to regulate the blood flow and/or the blood pressure by stimulating smooth-muscle cells, resulting in contraction and a change in the calibre of the vessels. Capillaries and venules, which have a higher permeability, received weaker innervation by the vasomotor nerves than did arterioles. The intimate relation between vasomotor nerves and arterioles is related to the function of dental pulp in normal and pathological conditions.

Adrenergic Fibers↗
PubMed1994

Partial characterization of endothelin-converting enzyme activity in human serum lipoproteins.

Endothelin (ET)-1 is an endothelium-derived vasoconstrictor and mitogen peptide generated from an intermediate form (big ET-1) by endothelin-converting enzyme(s) (ECE). In this study, we partially characterized ECE activity in human serum lipoprotein fraction. By gel filtration chromatography, lipoprotein ECE activities consisted of three major components: the first and the second peak eluted in the positions of very low density lipoprotein (VLDL) and low density lipoprotein (LDL), respectively, while the third peak eluted earlier than that of high density lipoprotein (HDL), whose apparent molecular weight (550 kDa) was similar to that of apolipoprotein B (apo B). Both VLDL/LDL-associated and free ECE fractions were similarly inhibited by metalloproteinase and serine proteinase inhibitors. Free ECE fraction was precipitable with dextran sulphate and manganese ion in the same manner as lipoprotein ECE. Apo B purified by high performance liquid chromatography had the same ECE activity as lipoprotein ECE, whose activity was removed after immunoprecipitation with polyclonal anti-apo B antibody. Our data suggest that ECE activity in human serum lipoproteins may be associated with an apo B-like component, although it needs to be characterized completely.

Apolipoproteins B↗
PubMed1994

The proliferative activity in dysplasia and carcinoma in situ of the uterine cervix analyzed by proliferating cell nuclear antigen immunostaining and silver-binding argyrophilic nucleolar organizer region staining.

The proliferative activity of dysplasia and carcinoma in situ (CIS) in the uterine cervix was examined using proliferating cell nuclear antigen (PCNA) immunostaining and silver-binding argyrophilic nucleolar organizer region (AgNOR) staining. A significant difference in the labeling index of PCNA immunostaining obtained from dysplastic cells in each histopathologic category was demonstrated between severe dysplasia and CIS. There was no significant difference among each category of dysplasia. The frequency of mitotic figures was highest in CIS, followed in decreasing order by severe, moderate, and mild dysplasia, and was closely correlated with the histopathologic classification. There was an intimate correlation between the PCNA and mitotic indexes in severe dysplasia and CIS. However, the mean numbers of AgNORs in each category of dysplasia and CIS were not significantly different, and there was no apparent relationship with the histologic classification. The PCNA index seemed to be a useful means of evaluating proliferative activity in dysplasia and CIS, and especially in distinguishing CIS from severe dysplasia. In addition, the present PCNA index suggests that a considerable alteration of the biologic behavior involving genetic changes occurs during the progression of carcinogenesis from severe dysplasia to CIS. However, AgNOR staining did not appear to reliably represent the proliferative activity in these lesions.

Antigens, Neoplasm↗
PubMed1994

Photokilling of T-24 human bladder cancer cells with titanium dioxide.

A photoexcited titanium dioxide surface has a strong ability to decompose water into hydrogen and oxygen. We have studied this effect in order to use it to kill cancer cells in vitro and in vivo. A distinct cell killing effect was observed on cultured T-24 human bladder cancer cells treated with titanium dioxide particles and 300-400 nm UV light irradiation. Titanium dioxide plus UV light also dramatically suppressed the tumour growth of T-24 cells that were implanted in nude mice. Cells cultured on the titanium dioxide electrode were also killed under UV irradiation when the electrode was anodically polarised, suggesting that photogenerated holes are involved in the cell killing. The cell killing effect caused by titanium dioxide particles plus UV light irradiation was significantly hampered in the presence of L-cysteine and catalase, scavengers of hydroxyl radicals and hydrogen peroxide respectively. Transmission electron microscopic observations showed the titanium dioxide particles to be distributed on the cell surface and inside the cells. These results suggest that titanium dioxide particles under UV light irradiation produced photogenerated holes on the surface yielding hydroxyl radicals and hydrogen peroxide inside or outside the cells and the cells were then killed by the action of these highly oxidising molecules. The possible application of photoexcited titanium dioxide particles to cancer treatment as a new anti-cancer modality is discussed.

Catalase↗
PubMed1994

Fc alpha R expression on polymorphonuclear leukocyte and superoxide generation in IgA nephropathy.

Superoxide (O2-) production and Fc alpha R antigen expression of circulating polymorphonuclear leukocytes (PMNL) isolated from patients with IgA nephropathy (IgAN) and non-IgA mesangial proliferative glomerulonephritis (PGN) and healthy volunteers were investigated to establish their biological importance in the immunopathogenesis of mesangial proliferative glomerulonephritis. PMNL from both patient groups showed increased O2- production when stimulated with N-formyl methionyl leucyl phenylalanine (FMLP) and phorbol myristate acetate (PMA). The increased O2- generation demonstrated a positive correlation with the degree of proteinuria. Aggregated IgA caused enhanced O2- production only in patients with IgAN who also showed a significant correlation with proteinuria. Increased expression of Fc alpha R on circulating PMNL was observed in IgAN patients as determined by flow cytometric analysis. The amount of Fc alpha R on PMNL was positively correlated with O2- generation triggered with IgA aggregates. These results suggest that: 1. Circulating PMNL may potentially be participating in the pathogenesis of glomerular injury in mesangial proliferative glomerulonephritis, and 2. IgA aggregates/immune complexes may contribute to the immunopathogenesis of IgAN through augmenting the Fc alpha receptor-mediated generation of superoxide anion.

Adult↗
PubMed1994

Intratumor ethanol injection therapy for solitary minute hepatocellular carcinoma. A study of 37 patients.

To evaluate the effect of percutaneous ethanol injection given alone, we studied disease recurrence and prognosis in 37 patients with solitary hepatocellular carcinoma up to 2 cm. The patients were classified as Child's class A, 22; B, 11; and C, 4. During follow-up for periods ranging from 10 to 44 (mean, 26) months, 15 of the 37 patients (40.5%) had disease recurrence. The 1-, 2-, and 3-year recurrence rates were 37, 49, and 53%, respectively (Kaplan-Meier method). Significant risk factors for recurrence included the hypervascularity and the histological differentiation of the tumor (p < 0.01). Of those 15 patients, two had local recurrence, eight had nodular recurrence (fewer than two nodules), and five had widespread multinodular recurrence. The patients with local or nodular recurrence then received repeated injections of ethanol, while those with multinodular recurrence received transarterial embolization or chemolipiodolization therapy as possible. Seven of the 37 patients died during follow-up. The 1-, 2-, and 3-year survival rates were 95, 81, and 70%, respectively (Kaplan-Meier method). No factor was significant in prognosis. We observed a significant relationship between recurrence pattern and prognosis. Patients with a widespread multinodular recurrence had a significantly shorter survival (p < 0.01). In summary, ethanol injections given alone appeared to be effective in treating small and solitary hepatocellular carcinomas. Repeated injection of ethanol of the site of recurrence was useful in prolonging survival.

Adult↗
PubMed1994

Human immunodeficiency virus Vpx is required for the early phase of replication in peripheral blood mononuclear cells.

Functional importance of Vpx protein of human immunodeficiency virus type 2 was evaluated in various types of cells. In 8 lymphocytic or monocytic cell lines tested, vpx mutant virus grew as well as wild-type virus. Only in primary peripheral blood mononuclear cell cultures, severely retarded growth of mutant virus was observed. No replication of vpx-minus virus was detected in primary macrophage cells. A highly sensitive single-round replication assay system was used to determine the defective replication phase in primary mononuclear cells of vpx mutant virus. In all cell lines examined, vpx mutant displayed no abnormality. In contrast, the vpx mutant was demonstrated to be defective at an early stage of the infection cycle in primary cell cultures. No evidence of a replication-defect at a late phase in primary cells of the vpx mutant was obtained by a transfection-coculture method. These results indicate that the virion-associated Vpx protein is essential for early viral replication process in natural target cells such as primary macrophages.

Cell Line↗
PubMed1994

New human oral squamous carcinoma cell line and its tumorigenic subline producing granulocyte colony-stimulating factor.

A new human carcinoma cell line, MISK81-5, was established from a metastatic lymph node of oral squamous cell carcinoma. Immunocytochemical and ultrastructural observations revealed an obvious epithelial origin of the cell line. Chromosome analysis revealed a hypertriploid karyotype with numerical and structural anomalies. MISK81-5 cells could form a tumor mass in the subcutaneous tissue of recipient BALB/c athymic mice only when coinjected with Matrigel. A stem cell assay revealed that conditioned medium (CM) of MISK81-5 contained granulocyte colony-stimulating factor (G-CSF) or interleukin-6 activity. Quantitation by ELISA disclosed a higher concentration of G-CSF in the CM of MISK81-5 than in the CM of other squamous and gastric carcinoma cell lines. The sMISK, that was derived from MISK81-5 as a subpopulation of the cell line having higher tumorigenicity, also showed a similar hematopoietic stimulating activity to that of MISK81-5. These characteristics of the MISK81-5 cell line and its subpopulation, sMISK will be useful for studying the biological behavior of oral squamous cell carcinomas and its relation to hematopoietic stimulating factors.

Aged↗
PubMed1994

Clonality in chronic myeloproliferative disorders defined by X-chromosome linked probes: demonstration of heterogeneity in lineage involvement.

The restriction fragment length polymorphisms (RFLP) of the X-chromosome phosphoglycerate kinase (PGK) and hypoxanthine phosphoribosyltransferase (HPRT) genes were used to study the clonal basis of the chronic myeloproliferative disorders (CMPD). Analyses were performed on granulocyte and T-lymphocyte fractions obtained from 24 females; 13 had essential thrombocythaemia (ET), eight polycythaemia vera (PV) and three myelofibrosis with myeloid metaplasia (MMM). All 24 of these patients had monoclonal patterns of X-inactivation in the granulocyte fraction. For the T-lymphocyte fraction, non-clonal patterns of X-inactivation were observed in 8/13 patients with ET, 7/8 with PV and 1/3 with MMM, while the remaining eight subjects were found to have monoclonal patterns of X-inactivation. Our findings suggest that the majority of the CMPD in these patients originated from a relatively committed progenitor cell without the capacity to differentiate into T cells, and convincingly demonstrated heterogeneity of lineage involvement.

Adult↗
PubMed1994

Toward better home respiratory monitoring: a comparison of impedance and inductance pneumography.

Various respiratory monitoring methods have been used as a part of home respiratory care, but none has been accepted as a universal method. Impedance pneumography is the most popular method at present and is used in the form of cardiorespiratory monitoring, but it has limitations for diagnosing obstructive airway problems and a high incidence of false alarms. We evaluated a new investigational method, inductance pneumography, in terms of the incidence of false alarms (waveform out of range), using infants recovering from general anesthesia. They were used for this study because they go through all the stages of sleep in a short period and their relatively long period of light sleep was advantageous in evaluating motion artifact interference. Waveforms went out of range 24.6 +/- 2.9% of the time with impedance pneumography and 15.9 +/- 4.5% with pulse oximeter, but 11.0 +/- 3.4% with inductance pneumography. These differences are statistically significant (P < 0.01). Electrocardiography electrodes for impedance pneumography dislodged briefly in one case but the Respiband dislodged in four cases and the Flex II probe dislodged in three cases, indicating the need for better fixation of sensors. It was found that inductance pneumography, in addition to being able to detect obstructive apnea, has a significantly lower incidence of false alarms. Further elaboration of this method is warranted for better home respiratory monitoring.

Apnea↗
PubMed1994

Alternative treatment may lower the need for use of extracorporeal membrane oxygenation.

Access to artificial surfactant and high frequency oscillatory ventilation (HFO) in Japan seems to affect the actual indications for extracorporeal membrane oxygenation (ECMO). The relation between the methods of treatment and survival and/or neurological sequelae of 27 neonates with severe respiratory failure who would have met the US ECMO entry criteria in the Neonatal Intensive Care Unit of National Children's Hospital, Tokyo between January 1988 and May 1992 were retrospectively analyzed. Out of 27 neonates, conventional treatment including artificial surfactant was successful in 6 cases (22%). High frequency oscillatory ventilation was used for the 21 cases who did not respond to conventional treatment and it was effective in 5 cases (19% of total). Extracorporeal membrane oxygenation was used on 11 (40% of total) of 16 cases who did not respond to HFO. Eight (29% of total or 73% of ECMO cases) of these cases survived and 3 cases (11% of total) died. The remaining 5 cases (19% of total) who met the exclusion criteria of ECMO died. No patient with respiratory distress syndrome (RDS) became ill enough to meet the US ECMO entry criteria. Six out of 8 congenital diaphragmatic hernia cases were saved on a delayed surgery protocol with HFO. Only about 1% of the neonates who were admitted to our NICU during the last 4 years needed ECMO treatment. Forty-one per cent of the patients who would have met the US ECMO entry criteria were treated successfully without ECMO. The necessity for ECMO is less in Japan than in the US because other methods can often be used successfully to treat severe respiratory disorders.

Extracorporeal Membrane Oxygenation↗
PubMed1994

Comparative analysis of functional and structural features in the primase-dependent priming signals, G sites, from phages and plasmids.

The primase-dependent priming signals, G sites, are directly recognized by the Escherichia coli primase (dnaG gene product) and conduct the synthesis of primer RNAs. In nucleotide sequence and secondary structure, there is no striking resemblance between the phage- and plasmid-derived G sites, except for the limited sequence homology near the start position of primer RNA synthesis. In this study, we analyzed the structure and function of a G site of plasmid R100, G site (R100), and discovered the necessity of the coexistence of two domains (domains I and III), which contains blocks A, B, and C, which are nucleotide sequences highly conserved among the plasmid-derived G sites. However, neither the internal region, domain II, between domains I and III nor the potential secondary structure proposed by Bahk et al. (J. D. Bahk, N. Kioka, H. Sakai, and T. Komano, Plasmid 20:266-270, 1988) is essential for single-stranded DNA initiation activity. Furthermore, chimeric G sites constructed between a G site of phage G4, G site(G4), and G site(R100) maintained significant single-stranded DNA initiation activities. These results strongly suggest that phage- and plasmid-derived G sites have functionally equivalent domains. The primase-dependent priming mechanisms of phage- and plasmid-derived G sites are discussed.

Base Sequence↗
PubMed1994

Expression of intercellular adhesion molecule-1 and infiltration of lymphocytes in glomeruli of patients with IgA nephropathy.

Using immunofluorescence, we studied 19 patients with IgA nephropathy to determine whether the expression of intercellular adhesion molecule (ICAM)-1 in glomeruli might reflect the disease activity. The relationship between the expression of ICAM-1 and the infiltration of lymphocytes, monocytes and polymorphonuclear leukocytes (PMN) in glomeruli of IgA nephropathy cases was examined. The expression of ICAM-1 in patients in the advanced stage was significantly higher than that in patients in the mild stage. In double immunofluorescence, the distribution of ICAM-1 expression in glomeruli was different from that of IgA deposition in patients in both stages. Glomeruli which showed increases of ICAM-1 expression had marked infiltration of lymphocytes (OKT4+, OKT8+ T cells), and monocytes (OKM1+ cells). Increase of urinary protein and decreases in renal function were observed in patients in the advanced stage. It appears that the expression of ICAM-1 is closely linked to glomerular cell proliferation, and infiltration of lymphocytes and monocytes in patients with IgA nephropathy. However, the expression of ICAM-1 in glomeruli might not be correlated with IgA-dominant immune complexes in this disease.

Antibodies, Monoclonal↗
PubMed1994

Sugar chain heterogeneity of human urinary chorionic gonadotropin determined by serial lectin affinity chromatography: difference between benign and malignant disease.

Human chorionic gonadotropin (hCG) is a glycoprotein of which sugar chains are considered to show structural changes with malignancy. To study the sugar chain heterogeneity of urinary hCG in patients with gynecological disease, we employed serial lectin affinity chromatography (LAC) using concanavalin A (Con A) and phytohemagglutinin-E (PHA-E) which can separate N-glycoside-linked sugar chains, and Jacalin lectin which is specific for O-glycoside-linked sugar chains. The proportion of hCG which did not bind to Con A was clearly higher in patients with cervical cancer than in healthy pregnant women. The complex-type sugar chains bearing bisecting (beta 1-4) N-acetylglucosamine which bound to PHA-E increased in the early stage of cervical cancer, and tri- and tetra-antennary complex type sugar chains also increased in the advanced stages. In addition, the Jacalin-bound hCG increased significantly along with the stage of the cancer, especially in advanced cervical cancer with distant metastases. Taken together, these results show that alteration in sugar chain structures of hCG reflect the advanced stage of cervical cancer.

Carbohydrates↗