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Biomedical subjects

S Ichikawa

Publications and source records attributed to S Ichikawa.

At least 109 records · Page 6Linked to original sources
PubMed1998

[Magnesium and calcium changes in serum and atrial muscle caused by open heart surgery and the effect of preoperative oral magnesium administration].

The study was undertaken to compare magnesium and calcium serum concentration levels and magnesium and calcium atrial muscle content of between the non-magnesium group (20 patients) and the magnesium group (11 patients) in the perioperative period of open heart surgery. In addition, the incidence of arrhythmias was compared between the two groups. Late ventricular potentials and postoperative ventricular arrhythmias were evaluated in both groups. The patients of the magnesium group were administered a daily oral intake of 3.0 g of magnesium oxide for ten days before operation. In both groups, serum concentration of magnesium decreased abruptly due to hemodilution after the operation and began increasing gradually from 24 hours after the operation. However, in the non-magnesium group the concentration decreased below the normal range in the 24 hour period after the operation and elevated to above the preoperative value from the third to fifth postoperative days. In the magnesium group serum concentration of magnesium was higher during the 24 hours after the operation and lower from the third to fifth postoperative days than the non-magnesium group. Thus, the fluctuation was smaller in the magnesium group than the non-magnesium group. Serum concentration of calcium also decreased abruptly after the operation and gradually increased in the postoperative days in both groups. However, the level was always higher in the magnesium group than the non-magnesium group. The concentration ratio of serum calcium to magnesium was relatively unchanged postoperatively in the magnesium group, whereas it decreased significantly from the second to seventh postoperative days in the non-magnesium group. Magnesium and calcium contents in the atrial muscle were measured before and after cardiopulmonary bypass. Before bypass, magnesium and calcium contents were higher in the magnesium group than the non-magnesium group. However, in the non-magnesium group the calcium content increased significantly after bypass compared to pre-bypass levels, whereas it was unchanged in the magnesium group. Ventricular arrhythmias severer than grade 3 were found in 4 cases in the non-magnesium group. On the other hand, no ventricular arrhythmias severer than grade 3 were found in the magnesium group. As to the incidence of supraventricular arrhythmias, no difference was demonstrated between both groups. The appearance of late ventricular potentials on signal averaged electrocardiograms was found variable and often transient, and no association was found between the appearance of late ventricular potentials and the incidence of ventricular arrhythmias. Smaller fluctuations of magnesium and calcium concentrations in serum as well as in the atrial muscle were observed in the postoperative days in the magnesium group. Magnesium and calcium ratio also showed smaller fluctuations in the postoperative days in the magnesium group. In conclusion, these factors, along with suppression of calcium influx in the cardiac muscle, appeared to serve to reduce the incidence of ventricular arrhythmias in the magnesium group.

Administration, Oral↗
PubMed1998

Glucosylceramide synthase and glycosphingolipid synthesis.

In mammalian cells, there are two major classes of sphingolipids---sphingomyelin and glycosphingolipids (GSLs)--both of which are synthesized from the hydrophobic molecule ceramide. The synthesis of most GSLs begins with glucosylation of ceramide to form glucosylceramide (GlcCer), which, in turn, serves as the source of 300-400 GSLs. Although most of these GSLs have been characterized chemically, the biological functions of ceramide glycosylation and GSLs still remain enigmatic. The recent description of a GSL-deficient cell line and isolation of cDNA for GlcCer synthase provide new insights into GSL functions.

Amino Acid Sequence↗
PubMed1998

Molecular cloning and expression of mouse ceramide glucosyltransferase.

Ceramide glucosyltransferase (EC 2.4.1.80) catalyzes the first glycosylation step of glycosphingolipid (GSL) synthesis, the transfer of glucose from UDP-Glucose to hydrophobic ceramide and generate glucosylceramide (GlcCer). We have cloned mouse ceramide glucosyltransferase cDNA from a brain cDNA library by PCR based homology cloning. The nucleotide sequence determination revealed that mouse ceramide glucosyltransferase cDNA encodes 394 amino acids with a calculated molecular mass of 45 kDa. The amino acid sequence of mouse ceramide glucosyltransferase showed 98% identity with the human sequence. Homology searches against currently available databases identified three homologous proteins in Caenorhabditis elegans and one homologous protein in Cyanobacteria. Highly conserved sequences of ceramide glucosyltransferases and the homologs among a wide variety of organisms suggest biological significance of the lipid glucosylation system.

Amino Acid Sequence↗
PubMed1998

Risk factors for the development of hypertension: a 6-year longitudinal study of middle-aged Japanese men.

OBJECTIVE: To identify the factors related to the development of hypertension on the basis of annual health examinations at the workplace. SETTING: A cohort of Japanese male office workers who were reexamined for six successive years after their initial examinations in 1990. SUBJECTS: The study cohort comprised 1089 hypertension-free subjects aged 30-54 years. Six-year follow-ups were completed for 934 subjects (85.8%) RESULTS: An analysis using the Kaplan-Meier method showed that the incidence of hypertension above the borderline level increased significantly with increasing age, body mass index, systolic blood pressure, diastolic blood pressure, total cholesterol level, uric acid level, total protein level, hematocrit level, and alcohol intake. This increase was significant for systolic blood pressure, diastolic blood pressure, and hematocrit level. The highest cumulative incidences both of hypertension above the borderline level and of definite hypertension were observed among those with 85-89 mmHg diastolic blood pressure, and the second highest among those with 130-139 mmHg systolic blood pressure. Multivariate analysis using the Cox proportional hazards model indicated that age, systolic blood pressure, diastolic blood pressure, and alcohol intake were independent factors associated with the incidence of hypertension above the borderline level. Systolic blood pressure, diastolic blood pressure, and hematocrit level proved to be independently predictive of hypertension, and alcohol intake was of borderline significance as a risk factor for hypertension. CONCLUSION: High normal blood pressure is the strongest predictor for the development of hypertension among middle-aged Japanese men. In addition, high alcohol intake and high hematocrit level may be contributory factors.

Adult↗
PubMed1998

[Buckwheat allergy in 90,000 school children in Yokohama].

Hypersensitivity to buckwheat allergen frequently causes anaphylactic type reactions including urticaria, wheezing, dyspnea and/or shock. Though the susceptible pupil would be recommended to be careful for school lunch and picnic meals, the prevalence of buckwheat allergy in school children has not yet been elucidated. In this study, data on the children allergic to buckwheat were collected by sending questionnaire to 341 nurses in elementary school in Yokohama. Among the total subjects of this investigation, 92,680 children, the incidence of buckwheat allergy was determined 0.22% (140 boys and 54 girls). This percentage was not so low level besides the prevalence of such allergic diseases as bronchial asthma, atopic dermatitis, allergic rhinitis, allergic conjunctivitis and food allergy was 5.6%, 4.2%, 3.1%, 1.6%, and 1.3%, respectively. Although a large majority of clinical symptoms of buckwheat allergy were urticaria (37.3%), skin itching (33.3%), and wheezing (26.5%). Four children (3.9%) experienced anaphylactic shock having a need of medical emergency treatment. The incidence of anaphylactic shock due to buckwheat was higher than those due to egg and milk allergy. Actually 7 pupil was provoked allergic reaction by buckwheat noodle served at school lunch, and 1 pupil at picnic meals. Thus, school children allergic to buckwheat is not rare, and it is important to withdraw buckwheat food from school lunch and picnic meals.

Age Factors↗
PubMed1998

[Basic study of MR-dacryocystography].

We developed MR-dacryocystography as a non-invasive, safer imaging technique for canaliculi, the nasolacrimal duct and lacrimal sac by dropping saline solution and diluted Gd-DTPA solution into the eye. The diluted Gd-DTPA solution was found to create no local irritation in the eyes of rabbits and normal volunteers. Lacrimal sacs and ducts were well visualized in all of 10 normal volunteers by using the saline solution or the diluted Gd-DTPA solution. Canaliculi were visualized in 4-7 cases on thin-slice axial images. MR-dacryocystography was suggested to be a useful screening examination for lacrimal outflow disorders.

Adult↗
PubMed1998

Ischaemic electrocardiographic changes after massive blood transfusion: findings based on myocardial scintigraphy using 99mTc-MIBI and 123I-MIBG.

We performed myocardial scintigraphy on a patient with ischaemic electrocardiographic changes after massive blood transfusion. Although there was no defect by 99mTc-MIBI scintigraphy, 123I-MIBG scintigraphy was observed suggesting denervation after massive blood transfusion. Myocardial scintigraphy using 99mTc-MIBI or 123I-MIBG can be useful for the evaluation of myocardial dysfunction with reversible myocardial infarction.

3-Iodobenzylguanidine↗
PubMed1997

Young inflorescence-bearing shoots with roots of Tradescantia clone BNL 4430 cultivated in nutrient solution circulating systems: an alternative to potted plants and cuttings for mutagenicity tests.

The use of young inflorescence-bearing shoots with roots of Tradescantia clone BNL 4430 cultivated in a nutrient solution circulating (NSC) growth chamber was tested and developed as an alternative method for using Tradescantia plants in mutagenicity testings. The NSC growth chamber was designed for our requirements, based on trial cultivations of the shoots with roots in its smaller-sized prototype. The nutrient solution used was a 1/2500 Hyponex solution. The characteristics of this clone, i.e., many new shoots constantly emerging from the basal nodes one after another and its short height favorable for early flowering, made it possible to prepare many young inflorescence-bearing shoots with roots at one time. A simplified NSC cultivation system could also be developed at a lower cost, and by using it together with the NSC growth chamber, recycling of untreated materials was established for supplying steadily enough amounts of young inflorescence-bearing shoots with roots for mutagenicity testings. Compared with traditional methods of using potted plants or cuttings, the new method exhibited more stable flower production, better stamen-hair growth and a significantly lower spontaneous (background) mutation frequency, and could produce more inflorescences per space. The use of such young inflorescence-bearing shoots with roots was therefore judged to be satisfactory to serve as a new mutagenicity test system alternating with potted plants and cuttings.

Clone Cells↗
PubMed1997

Descriptive epidemiology of HIV/AIDS in Japan, 1985-1994.

The HIV epidemic in Japan appears to be following a unique course, with no predominance of homosexual contact over heterosexual contact in reported cases and relatively little transmission by injection drug users and commercial sex workers. Infection rates are still low compared with those in southeast Asia and Western countries: 404 cases of nonhemophiliac AIDS (287 Japanese, 117 foreigners) and 1,441 cases of nonhemophiliac HIV infection (634 Japanese, 807 foreigners) were reported as of the end of 1994. Nevertheless, the numbers are increasing and the importance of targeted prevention programs is clear, particularly among those at higher risk because of sexual practices, such as homosexual men and commercial sex workers and their clients, or because of injection drug use. More data are needed to assess the impact of HIV/AIDS in Japan. These should include surveillance data as well as results from epidemiologic and behavioral studies.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Upregulation of neuropeptides and neuropeptide receptors in a murine model of immune inflammation in lung parenchyma.

The lung is richly supplied with peptidergic nerves that store and secrete substance P (SP), vasoactive intestinal peptide (VIP), and other neuropeptides known to potently modulate leukocyte function in vitro and airway inflammation in vivo. To investigate and characterize neuromodulation of immune responses compartmentalized in lung parenchyma, neuropeptide release and expression of neuropeptide receptors were studied in lungs of antigen-primed C57BL/6 mice after intratracheal challenge with sheep erythrocytes. The concentrations of cytokines in bronchoalveolar lavage (BAL) fluid rose early and peaked on day 1 for interleukin (IL)-2, interferon gamma, and IL-10; days 1 to 2 for IL-6; and day 3 for IL-4, whereas the total number and different types of leukocytes in BAL fluid peaked subsequently on days 4 to 6 after i.t. antigen challenge. Immunoreactive SP and VIP in BAL fluid increased maximally to nanomolar concentrations on days 1 to 3 and 2 to 7, respectively in lungs undergoing immune responses. The high-affinity SP receptor (NK-1 R), and VIP types I (VIPR1) and II (VIPR2) receptors were localized by immunohistochemistry to surface membranes of mononuclear leukocytes and granulocytes in perivascular, peribronchiolar, and alveolar inflammatory infiltrates during immune responses. As quantified by reverse transcription-polymerase chain reaction, significant increases were observed in levels of BAL lymphocyte mRNA encoding NK-1 R (days 2 to 4), VIPR1 (days 2 to 4), and VIPR2 (days 4 to 6), and in alveolar macrophage mRNA encoding NK-1 R (days 2 to 6) and VIPR1 (days 2 to 4), but not VIPR2. Systemic treatment of mice with a selective, nonpeptide NK-1 R antagonist reduced significantly the total numbers of leukocytes, lymphocytes, and granulocytes retrieved by BAL on day 5 of the pulmonary immune response. The results indicate that SP and VIP are secreted locally during pulmonary immune responses, and are recognized by leukocytes infiltrating lung tissue, and thus their interaction may regulate the recruitment and functions of immune cells in lung parenchyma.

Animals↗
PubMed1997

Acute myocardial infarction due to vasospasm in a 13-year-old-boy.

We describe an unusual case of acute myocardial infarction due to vasospasm in a 13-year-old boy. He was admitted to our hospital with severe congestive heart failure and shock. He had experienced a feeling of chest oppression with dyspnea while running, which grew worse. He then lost consciousness and was brought by ambulance to our intensive care unit. He had had similar but milder episodes of chest oppression months earlier. The family history revealed that his father had died suddenly from hypertrophic cardiomyopathy and that his grandmother also had hypertrophic cardiomyopathy. On admission, the patient was bathed in a cold sweat, his pulse was weak, and his blood pressure was too low to measure. Coarse crackling and wheezing were audible in both lung fields. Administration of catecholamine and intra-aortic balloon pumping failed to stabilize the hemodynamic variables, but percutaneous cardiopulmonary support proved to be lifesaving. Coronary arteriography performed during his convalescence showed on evidence of atherosclerosis. The acetylcholine provocation test ultimately revealed a diagnosis of acute myocardial infarction due to vasospasm.

Acetylcholine↗
PubMed1997

Correlation between heart muscle damage and high-nutrient feed in broiler chickens.

One-day-old broiler chickens were given commercial chicken starters during first 4 weeks of growth. The chickens were then divided into two groups: one group was fed commercial intensive growers (control feed), and the other group was fed commercial broiler finishers (high-nutrient feed). Body weights were calculated weekly. At eight weeks old, blood samples were collected and heart tissues were examined histopathologically. Significant increases in body weight as well as pathological findings in the heart muscle and an elevation of serum creation kinase (CK) were observed in chickens fed with broiler finisher. Histopathological changes in heart fiber resembled that of sudden death syndrome, and this heart damage was thought to be related to the increase of CK levels.

Animal Feed↗
PubMed1997

Somatic mutation frequencies in Tradescantia stamen hairs treated with relatively low thermal neutron fluxes.

Young inflorescence-bearing cuttings of Tradescantia clone BNL 02, a blue/pink heterozygote, were treated with thermal neutrons for 12-120 s in the Irradiation Tube set in the Heavy Water Facility of the KUR Reactor of the Research Reactor Institute, Kyoto University. In this facility, practically all components of the neutron flux were thermal neutrons. The thermal neutron fluxes measured simultaneously with gold foils were 2.90-33.3 x 10(10) nth cm-2, and the gamma-ray contamination per 10(10) nth cm-2 was 2.58 x 10(-4) C/kg (1.0 R). The induced somatic pink mutation frequencies in the stamen hairs increased linearly with thermal neutron flux at a rate of 1.69 pink mutant events per 10(4) hair-cell divisions per 10(10) nth cm-2 in Experiments 1 and 2, but at a higher rate of 3.87 pink mutant events per 10(4) hair-cell divisions per 10(10) nth cm-2 in Experiment 3. The relatively small thermal neutron fluxes applied were calculated to have resulted in absorbed doses of 16.8-193 mGy, and the absorbed doses of contaminating gamma rays were 28.0-321 mGy. Therefore, these mutation frequencies could be converted into 109 and 251 pink mutant events per 10(4) hair-cell divisions per gray, including the contaminating gamma rays, and were 2.14-4.92 times higher than the 51.0 pink mutant events per 10(4) hair-cell divisions per gray for relatively small doses of acute X rays which was obtained in earlier studies. The relative biological effectiveness of heavy particles (p, alpha and 7Li) produced by thermal neutrons was calculated to be between 11.0 and 35.4 compared with acute X rays rather than with 18-20-h exposure to gamma rays, the value of 11.0 being considered to be more reliable.

Dose-Response Relationship, Radiation↗
PubMed1997

Synergistic effects of N-ethyl-N-nitrosourea (an alkylating agent with a low Swain-Scott substrate constant) and X-rays in the stamen hairs of Tradescantia clone BNL 4430.

The mutagenic interaction between N-ethyl-N-nitrosourea (ENU) and X-rays was tested in the stamen hairs of Tradescantia clone BNL 4430, a blue/pink heterozygote. ENU, a monofunctional alkylating agent with a low Swain-Scott substrate constant (s) of 0.26, exhibited a strong cytotoxicity. ENU-induced somatic pink mutation frequency per 10(4) hair-cell divisions increased with increasing ENU dose, with a slope of 1.243 on a log-log graph, the slope value being similar to that for X-ray-induced mutation frequency. Three out of five combined treatments with ENU and X-rays produced mutation frequencies significantly higher than those expected from the additive effects of the two mutagens. Clear synergistic effects were detected when relatively higher X-ray doses were applied, resembling those confirmed earlier between methyl methanesulfonate (MMS) and X-rays, although the s value for ENU is very much smaller than that (0.88) for MMS. It is therefore concluded that mutagenic interactions between alkylating agents and X-rays do not have any clear relationship with the s values.

Dose-Response Relationship, Radiation↗