Biomedical subjects

S Ichikawa

Publications and source records attributed to S Ichikawa.

At least 91 records · Page 5Linked to original sources

PubMed1999

Analysis of human IgE epitope of Der f 2 with anti-Der f 2 mouse monoclonal antibodies.

Der f 2 is one of the major mite allergens recognized by human IgE antibodies of allergic patients. Using five anti-Der f 2 mouse monoclonal antibodies, human IgE epitopes of Der f 2 were analyzed. Among them, two monoclonal antibodies 15E11 and 13A4 inhibited the binding between Der f 2 and human IgE antibodies. To determine major IgE epitopes of Der f 2, epitopes for the monoclonal IgG antibodies were analyzed using 43 single site Der f 2 mutants constructed by site-directed mutagenesis. Binding ability of 13A4 and 15E11 was decreased by the amino acid replacement around the C-terminus, and around 73rd, respectively. These results suggest that the C-terminal portion and the central portion around 73rd of Der f 2 were recognized by human IgE antibodies as major epitopes. The location of the putative IgE epitopes on 3-D structure of Der f 2 is also discussed.

Allergens↗

PubMed1999

Hormone replacement therapy in postmenopausal women with essential hypertension increases circulating plasma levels of bradykinin.

Hormone replacement therapy (HRT) reduces the incidence of cardiovascular disease (CVD) in postmenopausal women (PMW). Recently, it has been reported that HRT declines angiotensin converting enzyme (ACE) activity, which may be one of the factors protecting against CVD. We measured the plasma levels of bradykinin, which would be expected to increase because the bradykinin-degrading enzyme (kinase II) is the same as ACE. Treatment with conjugated estrogens (0.625 mg/day) and medroxyprogesterone (2.5 mg/ day) was given for 3 months as HRT to 19 hypertensive and 19 normotensive PMW. Plasma bradykinin and ACE activity levels were measured at baseline and after 3 months of HRT. The plasma levels of ACE activity in both the hypertensive and normotensive PMW were significantly reduced by HRT. The plasma levels of bradykinin in the hypertensive PMW were significantly increased by HRT, whereas the administration of HRT tended to increase plasma levels of bradykinin in the normotensive PMW. The increased bradykinin levels with a concomitant decrease of plasma ACE activity by HRT in hypertensive PMW seem to be beneficial for reducing the risk of CVD.

Aged↗

PubMed1999

Protein separation using affinity-based reversed micelles

Reversed micellar two-phase extraction is a developing technique for protein separation. Introduction of an affinity ligand is considered to be an effective approach to increase the selectivity and capacity of reversed micelles. In this article, Cibacron Blue F3G-A (CB) as an affinity ligand was immobilized to reversed micelles composed of soybean lecithin by a two-phase reaction. The affinity partitioning of lysozyme and bovine serum albumin (BSA) to the CB-lecithin micelles was studied. Formation of mixed micelles by additionally introducing a nonionic surfactant, Tween 85, to the CB-lecithin micelles was effective to increase the solubilization of lysozyme due to the increase of W0 (water/surfactant molar ratio)/micellar size. The partitioning isotherms of lysozyme to the CB-lecithin micelles with and without Tween 85 were expressed by the Langmuir equation. The dissociation constants in the Langmuir equation decreased on addition of Tween 85, indicating the increase of the effectiveness of lysozyme binding to the immobilized CB. On addition of 20 g/L Tween 85 to 50 g/L lecithin/hexane micellar phase containing 0.1 mmol/L CB, the extraction capacity for lysozyme could be increased by 42%. Moreover, the CB-lecithin micelles with or without Tween 85 showed significant size exclusion for BSA due to its high molecular weight. Thus, lysozyme and BSA were separated from artificial solutions containing the two proteins. In addition, the affinity-based reversed micellar phase containing Tween 85 was recycled three times for lysozyme purification from crude egg-white solutions. Lysozyme purity increased by 16-18-fold, reaching 60-70% in the recycled use.

Journal Article↗

PubMed1999

Relationship between lifestyle and serum lipid and lipoprotein levels in middle-aged Japanese men.

Cross-sectional associations between lifestyle factors [cigarette smoking, alcohol intake, overall obesity indicated by body mass index (BMI), eating breakfast, snacking between meals, considering nutritional balance, coffee drinking, physical exercise, and hours of work and sleep] and serum lipid and lipoprotein levels were examined in 1580 middle-aged Japanese men in Osaka, Japan. From stepwise regression analyses, significant correlates with low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and Log triglyceride levels were, in the order of relative importance: BMI, alcohol intake (negative), and age for LDL cholesterol level; BMI (negative), cigarette smoking (negative), alcohol intake, considering nutritional balance, and physical exercise for HDL cholesterol level; and BMI, cigarette smoking, working hours (negative), considering nutritional balance (negative), alcohol intake, and coffee drinking (negative) for Log triglyceride level. The cumulative percentages of variation for LDL cholesterol, HDL cholesterol and Log triglyceride levels were 4.2%, 15.4% and 14.7%, respectively. From stepwise regression analyses, excluding BMI as a factor in the model, snacking between meals emerged as a significant factor for LDL cholesterol level and HDL cholesterol level (negative). The cumulative percentage of variation for each serum lipid and lipoprotein level was decreased (1.5% for LDL cholesterol, 6.8% for HDL cholesterol, and 3.1% for Log triglyceride). These results suggest that BMI has the strongest association with serum lipid and lipoprotein levels and that good daily lifestyles may have an anti-atherogenic effect by altering serum lipid and lipoprotein levels in middle-aged Japanese men.

Body Mass Index↗

PubMed1999

Trends in HIV and AIDS based on HIV/AIDS surveillance data in Japan.

BACKGROUND: In recent years a decline in the number of new AIDS cases has been observed in several industrialized countries. It is important to know whether these recent trends observed in North America and Europe are also occurring in Japan. METHODS: The number of people reported with HIV and AIDS by nationality, route of infection, and sex was calculated based on the HIV/AIDS surveillance data available in Japan through December 1997. The effect of reporting delay, which was defined as those HIV and AIDS cases reported in the calendar year following diagnosis, on the trends was examined. The coverage rate in reporting HIV cases was estimated as the ratio of the reported AIDS cases with prior report as an HIV-positive to the total number of reported AIDS cases. RESULTS: The cumulative number of reported cases of HIV among Japanese and non-Japanese residents of Japan up to the end of 1997 were 1,300 and 1,190, respectively. The cumulative number of reported cases of AIDS among Japanese and non-Japanese up to the end of 1997 were 758 and 298, respectively. The number of reported cases of HIV among Japanese was found to be still increasing, with the major contribution from male cases. The increasing trend in the number of reported AIDS cases among Japanese began to slow in 1996 and 1997. The number of reported cases of HIV among non-Japanese residents of Japan peaked in 1992, and has decreased since then, and remained constant after 1994. In contrast, the number of reported AIDS cases among these non-Japanese tended to increase gradually. There was a slight reporting delay for people with HIV and AIDS. The estimated coverage rate in reporting HIV cases tended to decrease in 1996 and 1997 (1/7.2, 1/10.2, respectively). We point out several reasons for this recent decline and suggest the possibility of an ostensible decline in the estimates. CONCLUSIONS: We suggest that the number of people with HIV among Japanese has continued to increase, and that the increase in the number of AIDS cases among Japanese is now slowing.

Acquired Immunodeficiency Syndrome↗

PubMed1999

The first synthesis of herbicidin B, a tricyclic-sugar adenine nucleoside antibiotic, using samarium diiodide-promoted aldol-type C-glycosidation reaction as a key-step.

A first total synthesis of the nucleoside antibiotic herbicidin B (1) was achieved in which a novel aldol-type C-glycosidation reaction promoted by samarium diiodide (SmI2) was used as a key step. Construction of the desired stereochemistry of the tricyclic-sugar moiety was successfully achieved by conformational restriction strategy based on repulsion between adjacent bulky protecting groups on the pyranose ring.

Anti-Bacterial Agents↗

PubMed1999

Lifestyle and the development of hypertension: a 3-year follow-up study of middle-aged Japanese male office workers.

The association of lifestyle factors with the development of hypertension (blood pressure > or = 140/90 mmHg) over a 3-year follow-up period was studied in 949 hypertension-free Japanese male office workers aged 35 to 54 years. From the Cox proportional hazards model, age, alcohol intake, body mass index (BMI) and hours of work were independent factors associated with the development of hypertension. Adjusted hazard ratios for 5-year increases in age, daily consumption of alcohol, 5-kg/m2 increases in BMI and working 10 hours per day or more were 1.18 [95% confidence interval (CI) = 1.02-1.35]; 1.53 (CI = 1.14-2.05); 1.79 (CI = 1.38-2.33) and 0.58 (CI = 0.41-0.82), respectively. In the analysis using logistic regression, BMI was independently related to working 10 hours per day or more, controlling for other lifestyle factors. Adjusted odds ratio for 5-kg/m2 increase in BMI was 0.66 (CI = 0.49-0.88). These results suggest that the influences of long working hours on blood pressure are likely to be indirectly mediated through less overall obesity.

Adult↗

PubMed1999

An interleukin-6-producing cardiac myxoma associated with mediastinal lymphadenopathy.

We report our experience with a patient whose mediastinal lymphadenopathy resolved after resection of a cardiac myxoma that secreted interleukin-6 (IL-6). The patient was a 68-year-old female who complained of nocturnal chest discomfort related to congestive heart failure. An echocardiogram demonstrated a large left atrial mass. A computed tomogram showed not only the left atrial mass but multiple enlarged mediastinal lymph nodes. The serum IL-6 level was markedly elevated at 13.7 pg/ml. After resection of the cardiac myxoma, serum IL-6 returned to the normal range. A repeat computed tomogram showed no mediastinal lymphadenopathy. We believe that overproduction of IL-6 by the cardiac myxoma was the cause of the mediastinal lymphadenopathy.

Aged↗

PubMed1999

Labeled carcinoembryonic antigen antibodies excitable by infrared rays: a novel diagnostic method for micro cancers in the digestive tract.

OBJECT: An indocyanine green derivative (ICG-sulfo-OSu) was used as the labeling substance for monoclonal antibody, and a fluorescence imaging system appropriate for ICG-sulfo-OSu excitable by infrared rays (IR) was developed. The goal of this study was to demonstrate antibody labeling at the tissue level using this new imaging system. MATERIALS AND METHODS: ICG-sulfo-OSu labeled mouse anti-human carcinoembryonic antigen (CEA) monoclonal antibody, a newly developed imaging system, and an infrared ray microscope were employed in this experiment. Paraffin sections of human colon cancer previously proven to have cross-reactivity to anti-CEA antibody were examined. RESULTS: Positive staining was seen as a brownish discoloration of oxidized 3,3'-diaminobenzidine tetrahydrochloride (DAB) in sections that reacted with ICG-sulfo-OSu-labeled anti-CEA antibody, and the fluorescence was well-matched with the oxidized DAB-positive sites. CONCLUSION: Specific antibodies labeled with ICG-sulfo-OSu have significant affinity to cancer cells and seem to reflect sufficient amounts of fluorescence by IR to be useful in a system for the endoscopic detection of micro cancers using the immunohistochemical staining method.

Adenocarcinoma↗

PubMed1999

[A case of successful reoperation for aortic root pseudoaneurysm ruptured into right ventricle after modified Bentall operation].

The patient was a 51-year-old man with Marfan syndrome who had simultaneously undergone modified Bentall operation (Carrel patch method) and coronary artery bypass grafting. Prosthetic valve endocarditis (PVE) occurred 19 months after the operation. PVE had thereafter been treated by antibiotic therapy for 3 months, but echocardiography revealed prosthetic valve detachment and aortic root pseudoaneurysm ruptured into the right ventricle which appeared to have been caused by PVE. At reoperation there were no laboratory or intraoperative findings indicative of ongoing inflammation or infection. The composite graft, therefore, didn't require replacing, and it was possible to simply re-suture the composite graft and directly close the tear. The postoperative course has been uneventful with no further evidence of endocarditis.

Aneurysm, False↗

PubMed1999

The utility and limitations of an ultrasonic miniprobe in the staging of gastric cancer.

To determine the utility and limitations of an ultrasonic miniprobe (UMP) in the staging of gastric cancer, we evaluated 46 patients who underwent endoscopic ultrasonography (EUS) using an UMP and who were histologically determined to have gastric cancers. In every case, UMP findings were compared with histopathological findings after treatment. The total accuracy of UMP relative to the depth of tumor invasion was 71.7% (33/46 cases). Accuracy with respect to T1-m tumor diagnosis was 75.7% (22/29 cases), and for T1-sm, 76.9% (10/13 cases), but accuracy for T2 tumor diagnosis was low, due to ultrasound attenuation. When the analysis was carried out based on the size of tumor, the accuracy for UMP was 50.0% (9/18 cases) for all tumors over 20 mm and 85.7% (24/28 cases) for all tumors smaller than 20 mm. We conclude that UMP is suitable for investigation of tumor extension when the lesion is superficial and/or small gastric cancers which do not cause ultrasonic attenuation, but not when the tumor is large or located in certain sites, although conventional EUS is useful in some of these cases.

Aged↗

PubMed1999

[The survey of HIV infection among clients of foreign female prostitutes in Tokyo Metropolitan].

OBJECTIVES: It is important to elucidate the risks to foreign female prostitutes of HIV infection from their clients. We determined the prevalence of HIV among clients of foreign female prostitutes using anonymous testing of condom semen samples. METHODS: A total of 250 client condom semen samples were collected with client age and nationality by 15 Latin American and 37 Thai female prostitutes in Tokyo from March to May 1995. We screened by ELISA (GENELAVIA MIXT, Pasteur Sanofi Diagnostics) for antibody to HIV 1 and 2, and then confirmed by Western Blot (LAV Blot 1, LAV Blot 2, Sanofi Diagnostics Pasteur) and distinguished by Immuno Blot PEPTI-LAV 1, 2, (Sanofi Diagnostics Pasteur). RESULTS: The nationality of customers was reported as Japanese (74.8%), Iranian (7.6%), Pakistan (5.6%), Indian (2.8%), Taiwanese (2.0%), and Chinese (1.2%) with other nationalities less than 1.0%. Estimated age categories of the clients were < 20 (1.2%), 20-29 (41.2%), 30-39 (36.4%), 40-49 (12.4%), > or = 50 (6.4%) and undetermined (2.4%). Of the 250 samples collected, only 219 were sufficient for testing. Two samples (0.90%, 95% CI = 0.4-2.2%) were HIV 1 positive, both from Japanese clients (1.2% of Japanese clients, 95% CI = 0.5-2.9%). These data suggested that the prevalence of HIV in clients of female prostitutes was relatively high, and can be considered a risk group in Japan. The sentinel surveillance by anonymous of client condom semen samples is a very useful method to quantify HIV prevalence in this risk group.

Acquired Immunodeficiency Syndrome↗

PubMed1999

Steroid therapy is effective in a young patient with an inflammatory abdominal aortic aneurysm.

We report a successful resection of an inflammatory aneurysm following treatment with steroids in a 23-year-old man. Suffering from fever and severe lumbago, he was admitted to our hospital. An ultrasound and computed tomography of the abdomen revealed an infrarenal abdominal aortic aneurysm surrounded by dense perianeurysmal fibrous tissue. We diagnosed it as an inflammatory abdominal aortic aneurysm based on a symptomatic inflammatory reaction and the findings of ultrasound and computed tomography. Since the aneurysmal wall strongly adhered to the surrounding tissues and surgery was ruled out when it proved impossible to expose the vessels sufficiently to obtain vascular control, steroid therapy was started to control fever and severe lumbago. Five months later, we undertook surgery. Our conclusion is that steroid therapy was very effective against a young patient with inflammatory abdominal aortic aneurysm.

Adult↗

PubMed1998

Molecular cloning and characterization of the mouse ceramide glucosyltransferase gene.

Ceramide glucosyltransferase (glucosylceramide synthase, GlcT-1, EC 2.4.1.80) catalyzes the first step in glycosphingolipid synthesis, the transfer of glucose from UDP-glucose to ceramide. The product, glucosylceramide, serves as a core structure for over 300 species of glycosphingolipids. The enzyme is a key regulatory factor controlling intracellular levels of ceramide and glycosphingolipids. We have cloned the gene for mouse ceramide glucosyltransferase, Ugcg. The gene spans approximately 32 kb and is composed of 9 exons and 8 introns. The promoter region was found to lack TATA and CAAT boxes but contains Spl binding sites, which are indicators of typical housekeeping genes. In addition to these general transcription factor binding sites, the motifs for AhR, NF-kappaB, AP-2 and GATA-1 binding sites were found.

Animals↗

PubMed1998

Thermal and deformation analyses of side-cooled monochromator mirrors for the SPring-8/Figure-8 soft X-ray undulator.

The numerical results for a bent parabolic mirror monochromator designed for the SPring-8/Figure-8 soft X-ray undulator are described. A thermal and structural finite-element analysis is presented for side-cooled premirrors of the bent parabolic mirror monochromator. Using a ray-tracing code, the effect of the final induced figure errors on the performance of the premirror are discussed.

Journal Article↗

PubMed1998

Affinity extraction of proteins with a reversed micellar system composed of Cibacron Blue-modified lecithin.

Crude soybean lecithin was used as a novel surfactant to form reversed micelles in n-hexane. Cibacron Blue F-3GA (CB) was directly immobilized to the reversed micelles by a two-phase reaction. The reversed micellar system without CB showed low solubilizing capacity for low molecular weight proteins, lysozyme, and cytochrome c due to the weak electrostatic interactions. The introduction of CB significantly increased the solubilization of lysozyme because of its affinity binding to CB but showed no effect on the solubilization of cytochrome c since it did not bind to CB. Although bovine serum albumin had an affinity for CB, it was not extracted to the reversed micelles containing CB because its high molecular weight resulted in a significant steric hindrance effect. Thus the reversed micellar system had a high selectivity resulting from both biospecific and steric hindrance effects. The extraction yield of lysozyme decreased significantly with increasing ionic strength. Therefore, the back extraction of lysozyme was carried out using a stripping solution with an ionic strength of 0.865 mol/L. The overall recovery yield of lysozyme after back extraction could be increased to 87% by stripping for 2 h. The recovered lysozyme exhibited an activity equivalent to native lysozyme, and its secondary structure was also unchanged.

Animals↗

PubMed1998

Mutagenic interactions between X-rays and two promutagens, o-phenylenediamine and N-nitrosodimethylamine, in the stamen hairs of Tradescantia clone BNL 4430.

Mutagenic interactions between X-rays and two promutagens, o-phenylenediamine (PDA) and N-nitrosodimethylamine (DMN), were studied in the stamen hairs of Tradescantia clone BNL 4430, a blue/pink heterozygote. The young inflorescence-bearing shoots with roots of this clone cultivated in a nutrient solution circulating growth chamber were used as tester plants. After determining dose-response curves for X-rays. PDA and DMN, combined treatments with PDA or DMN and X-rays were conducted, exposing acutely to X-rays 20 h before starting, at the midpoint of, or 20 h after completing the PDA or DMN treatments for 4 h. Clear synergistic effects in inducing somatic pink mutations were detected when X-rays were irradiated before the PDA or DMN treatments, resembling those confirmed earlier between maleic hydrazide (MH) and X-rays. On the contrary, clear antagonistic effects were observed when X-rays were given after the PDA or DMN treatments, also resembling those between MH and X-rays. When X-rayed at the midpoint of the PDA or DMN treatments, merely additive and synergistic effects were observed, respectively, differing from the antagonistic effects between MH and X-rays. The mutagenic synergisms detected were considered to be the results of interactions between DNA strand breaks (and the resultant chromosome breaks) induced by X-rays and those by PDA or DMN, whereas the mutagenic antagonisms observed were presumed to be due to X-ray-caused inhibition of the activation of PDA and DMN in the stamen-hair cells. The time periods required for penetrations into floral tissues and/or activations into mutagens seem different among PDA, DMN and MH.

Dimethylnitrosamine↗

PubMed1998

Solution structure of Der f 2, the major mite allergen for atopic diseases.

House dust mites cause heavy atopic diseases such as asthma and dermatitis. Among allergens from Dermatophagoides farinae, Der f 2 shows the highest positive rate for atopic patients, but its biological function in mites has been perfectly unknown, as well as the functions of its homologs in human and other animals. We have determined the tertiary structure of Der f 2 by multidimensional nuclear magnetic resonance spectroscopy. Der f 2 was found to be a single-domain protein of immunoglobulin fold, and its structure was the most similar to those of the two regulatory domains of transglutaminase. This fact, binding to the bacterial surface, and other small pieces of information hinted that Der f 2 is related to the innate antibacterial defense system in mites. The immunoglobulin E epitopes are also discussed on the basis of the tertiary structure.

Allergens↗