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Biomedical subjects

T Mikami

Publications and source records attributed to T Mikami.

At least 559 records · Page 31Linked to original sources
PubMed1989

[Lymphocytic adenohypophysitis: MRI findings of a suspected case].

We report a case of a 26-year-old woman who had developed decrease of visual acuity, and restriction of the temporal visual field of the left eye in the 30th week of gestation. A skull roentgenogram showed no abnormality, but a pituitary mass was visualized by plain computed tomographic scan. Magnetic resonance imaging (MRI) demonstrated a symmetric sellar mass which had homogeneous signal intensity in all pulse sequences. T1 relaxation time of the mass was elongated as compared with that of a normal pituitary gland. The height of the mass was 11mm, and optic chiasm appeared compressed by the mass. Her visual disturbance improved before delivery, and the size of the pituitary mass regressed spontaneously. Although no histological examination was carried out, the most likely explanation for this phenomenon is lymphocytic adenohypophysitis. Early surgical intervention is not required for lymphocytic adenohypophysitis, because this disorder may be self-limiting, and may resolve itself. Most of these cases have been reported in women, often coincident with pregnancy. So we consider that MRI is the most useful and safest method for diagnosis and follow-up of this disease.

Adult↗
PubMed1989

The effect of left ventricular assist device (LVAD) on cardiac reserve in dogs.

The effect of LVAD on the preservation of cardiac reserve against ischemic damage was studied using Sarnoff's ventricular function curve. An LVAD was implanted between the canine left atrium and the aorta. Left ventricular function was measured by changing the height of the reservoir connected to the left atrium. The left ventricular function curve (LVFC) was drawn by plotting left ventricular stroke work (LVSW) against left atrial pressure (LAP). The coronary artery was occluded under a pump-on (ON group) or pump-off (OFF group). After reperfusion, measurements were repeated and changes in the LVFC caused by ischemia were compared in both groups. The gradient of the LVFC was significantly reduced by ischemia (107 +/- 15 ml/beat----80 +/- 14, n = 13) but not in the ON group. LVSW under normal preload did not significantly change in either group. This suggests that the LVAD preserved cardiac reserve against ischemic damage.

Animals↗
PubMed1989

[Effect of exercise on urate excretion].

Bidirectional renal urate transport was studied in normal male subjects, aged 21-26 yr. They performed a exhaustive running on treadmill for about 10 mins, after oral intake of each medicine. The used medicines were probenecid inhibited presecretory reabsorption, pyrazinamide inhibited tubular secretion and benzbromarone inhibited postsecretory reabsorption. The results were as follows: 1) Glomerular filtration rate decreased only 3 min after exercise, compared with resting level. 2) Presecretory reabsorption rate did not change substantially after exercise, compared with resting level. 3) Tubular secretion rate markedly decreased at 30 min and 1 hour after exercise, compared with resting level. 4) Postsecretory reabsorption rate changed as well as changes in tubular secretion rates.

Adult↗
PubMed1988

Myocardial oxygen tension during left ventricular bypass.

The effect of an assist pump on the heart was evaluated on the basis that myocardial gas tensions reflect the balance between oxygen supply and consumption in local regions of the myocardium. A left ventricular assist device (LVAD) was implanted in dogs between the left ventricle (LV group), or the left atrium (LA group) and the aorta. The assist pump was driven in a counterpulsation mode. A silicone catheter for mass spectrometry was inserted into the myocardium to monitor continuously myocardial oxygen and carbon dioxide tensions (PmO2, PmCO2). Coronary sinus blood flow (CSBF) was measured by completing an extracorporeal flow loop between the coronary sinus and the jugular vein. During LVAD counterpulsation, the LV pressure was reduced and diastolic arterial pressure (i.e. coronary perfusion pressure) was increased. Total LV bypass was obtained in the LV group, and partial LV bypass in the LA group. In the LV group, PmO2 was 18.3 +/- 1.9 mmHg with pump-off and increased to 26.4 +/- 3.0 during LV bypass (N = 10, p less than 0.005). PmCO2 was 45.3 +/- 1.8 mmHg with pump-off and decreased to 40.2 +/- 1.5 during bypass (N = 10; p less than 0.005). CSBF significantly decreased during LV bypass from a control value of 24.1 +/- 2.74 ml/min/100g to 16.3 +/- 1.69 in LV group (N = 10; p less than 0.001). It was 43.4 +/- 8.0 ml/min/100g in the pump-off and 31.9 +/- 7.2 during LV bypass in the LA group (N = 7; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Arteriosclerotic change in the human abdominal aorta in vivo in relation to coronary heart disease and risk factors.

In 137 living subjects, arteriosclerotic change in the human abdominal aorta was examined in relation to coronary heart disease (CHD) using a new ultrasonic method. The pressure strain elastic modulus (Ep) was calculated as an index of elastic properties from which arteriosclerotic change in the aorta was estimated. Thirty-one patients with CHD and 36 subjects with hypertension showed progression of the arteriosclerotic change in the abdominal aorta compared with 70 normal controls with the same age distribution (40-60 yrs). The Ep values were 1.03 +/- 0.27 X 10(6) dyne/cm2 in the normal group, and were elevated significantly (P less than 0.001) to 1.81 +/- 0.55 X 10(6) dyne/cm2 in the CHD group, and 1.95 +/- 1.31 X 10(6) dyne/cm2 in the hypertensive group. A significant correlation (r = 0.49, P less than 0.01) between the Ep values of the abdominal aorta and serum total cholesterol was observed in the CHD group. It was shown in living human subjects that the progression of arteriosclerotic change in the abdominal aorta was associated with coronary heart disease, and that some coronary risk factors, such as hypertension and serum total cholesterol, also affected arteriosclerotic change in the abdominal aorta.

Aorta, Abdominal↗
PubMed1988

Chemotactic response of human neutrophils to N-acetyl chitohexaose in vitro.

N-Acetyl chitohexaose (NACOS-6) was able to display chemotactic response of human neutrophils in vitro. In order to analyze the mechanism, a series of chemotaxis studies by means of neutrophils treated with inhibitors of phospholipase A2, cyclooxygenase, or lipoxygenase to NACOS-6 was conducted. The treatment of neutrophils with inhibitors of phospholipase A2 or cyclooxygenase resulted in decrease of number of migrated cells. However, the lipoxygenase inhibitors did not exhibit the same effect. On the other hand, the treatment of neutrophils with inhibitors of phospholipase A2 or lipoxygenase resulted in decrease of chemotactic response to Formyl-Met-Leu-Phe (FMLP), although the cyclooxygenase inhibitors did not inhibit chemotaxis of neutrophils. Neutrophils added to exogenous prostaglandin E2 (PGE2) caused an enhanced chemotactic response to NACOS-6. These results indicate that the mechanism of chemotactic response to NACOS-6 was different from that of FMLP, and that the response was enhanced by PGE2 released from the neutrophils with stimulation of NACOS-6.

Adult↗
PubMed1988

Production of leukotrienes from mouse peritoneal macrophages by treatment with a neutral subfraction of bakers' yeast mannan.

We concluded that a neutral subfraction of mannan from bakers' yeast (Saccharomyces cerevisiae wild type strain), abbreviated as WNM, was able to induce the release of leukotrienes from mouse peritoneal macrophages (M phi). The culture supernatant fluid of M phi from normal mice cultured with WNM caused a marked contraction of guinea pig ileum. This activity was inhibited by pretreatment of M phi with inhibitor of phospholipase A2 or lipoxygenase before M phi were treated with WNM, and by treatment of the incubation bath with a slow reacting substance antagonist, FPL55712. On the other hand, pretreatment of M phi with a cyclooxygenase inhibitor potentiated contractile response of ileum by culture supernatant fluid of M phi. A high performance liquid chromatographic analysis of a culture supernatant fluid of M phi treated with WNM demonstrated the presence of leukotrienes C4 and D4, and their related compounds.

Animals↗
PubMed1988

Mitral valve and its ring in hypertrophic cardiomyopathy--a mechanism creating surplus mitral leaflet involved in systolic anterior motion.

A large surplus portion of the mitral leaflets appears to be involved in the systolic anterior motion (SAM) of the mitral valve in hypertrophic cardiomyopathy (HCM). To understand the exact features and the mechanism of the surplus leaflet, we studies the mitral valve and its ring quantitatively with two-dimensional echocardiography in 17 patients with HCM (5 with large SAM, 6 with small SAM and 6 without SAM) and 10 normal subjects. In the large SAM group, the surplus length of the anterior mitral leaflet (AML) increased but that of the posterior mitral leaflet (PML) did not increase when compared to the other 3 groups. In the large SAM group, the length of AML was greater than in the normal group and the length of PML was greater than in the other 3 groups. The mid-systolic anteroposterior diameter of the mitral ring did not differ among the 4 groups. The mid-systolic position of the coaptation was more anterior in the large SAM group than in the other 3 groups. In conclusion, the surplus size of AML is actually increased in the patients with HCM and large SAM, which is caused by the elongation of both AML and PML with anteriorly displaced coaptation and with no dilation of the mitral ring.

Adolescent↗
PubMed1988

Quantitative precipitin reaction and enzyme-linked immunosorbent assay of mannans of Candida albicans NIH A-207 and NIH B-792 strains compared.

We assessed the difference between results by enzyme-linked immunosorbent assay (EIA) in plastic support wells and the quantitative precipitin reaction (QPR) in glass test tubes for antigenic mannans and antibodies of two representative Candida albicans strains, NIH A-207 and NIH B-792. We investigated each of four mannan subfractions, with different phosphate contents, for their reactivities to the homologous polyclonal rabbit antiserum. Each series of mannan subfractions showed a reactivity proportional to their phosphate content in EIA, in a similar manner as observed in QPR. Moreover, in EIA, the cross-reactivities between the bulk mannans of the two C. albicans strains and the polyclonal antiserum of a Saccharomyces cerevisiae wild-type strain containing specific antibodies to the non-reducing terminal alpha-1,3-linked D-mannopyranose unit resembled those of the same antigen-antibody reactions in QPR. However, the mannan of C. albicans NIH A-207 strains, a weak antigen in the cross-QPR system, reacted fairly strongly in EIA in its high concentration range, indicating that EIA can be used to detect such an epitope in these mannans in concentrations undetectable by QPR. We conclude that EIA is a useful technique for immunochemical assay of yeast mannans and their antibodies on a smaller scale than with QPR.

Candida albicans↗
PubMed1988

[Re-evaluation of determinants of the cardiothoracic ratio using two-dimensional echocardiography].

To evaluate the correlation of cardiothoracic ratios (CTR) on chest radiography with the sizes of the four cardiac chambers, we studied 41 normal persons and 77 cardiac patients using two-dimensional echocardiography (2DE). The transverse cardiac diameter and the CTR were ascertained from their chest radiographs. Using 2DE, each cardiac chamber was evaluated three-dimensionally, by measuring the short and long diameters of each left (LV) and right ventricle (RV), the diameter of the RV outflow, the anteroposterior, transverse, and long diameters of each left (LA) and right atrium (RA). These values were corrected using the square root of the body surface area. The correlation coefficient for the CTR was greatest in the long diameter of the LA (r = 0.84), and was greater in the atrial diameters (r greater than or equal to 0.71) than in the other diameters except for the transverse diameter of the RA (r less than or equal to 0.51). The contribution of each cardiac chamber to the transverse cardiac diameter was evaluated in 34 patients with cardiac enlargement by a method using the null hypothesis, which we originally designed. Consequently, the contribution of the LV to the CTR was definitely proven in two patients, that of RV in two, that of LA in 15 and that of RA in nine. These results indicated that the CTR is strongly influenced by enlargement of the LA.

Echocardiography↗
PubMed1988

Preparation of monoclonal antibodies reactive with beta-1,2-linked oligomannosyl residues in the phosphomannan-protein complex of Candida albicans NIH B-792 strain.

Hybridomas obtained by fusing the spleen cells of BALB/c female mice hyperimmunized with heat-killed yeast-form cells of Candida albicans NIH B-792 strain and a mouse myeloma cell line, P3X63Ag8.653, produced antibodies to beta-1,2-linked oligomannosyl residues in the phosphomannan-protein complex of the parent cells. Most of these monoclonal antibodies were IgM, but about 10% of the hybridomas produced IgG1 immunoglobulins. Ascites fluid from BALB/c mice inoculated with an IgG1-producing hybridoma showed different precipitability with the phosphomannan-protein complexes of three representative C. albicans strains, with NIH B-792 (serotype B) greater than NIH A-207 (serotype A) greater than J-1012 (serotype A, formerly serotype C). In contrast, a rabbit polyclonal antiserum to C. albicans NIH B-792 cells was unable to distinguish these same complexes. This ascites fluid agglutinated the heat-killed cells of three Candida strains, but not those of three others or of Torulopsis glabrata IFO 0622. The other ascites fluids, containing antibodies of the IgM class, agglutinated cells from three C. albicans strains and also C. tropicalis IFO 0587 cells.

Agglutination Tests↗
PubMed1988

[Intraarterial chemo-embolization with adriamycin containing albumin microspheres].

For local treatment of inflammatory breast cancer and recurrent breast cancers with liver metastasis, we applied intraarterial infusion chemoembolization therapy utilizing albumin microspheres containing adriamycin (ADM-ms), which was developed by Morimoto. In this study, there were 2 cases of inflammatory breast cancer and 3 cases of recurrent breast cancers with liver metastasis. Arterial canulation of primary breast cancer were made through both arteries, the internal mammary artery and lateral thoracic artery, which were feeding arteries of the breast. ADM-ms was injected into both arteries and its tumor effect was evaluated clinically and histologically. Remarkable reduction in tumor size was recognized. Histologic examination of resected specimens revealed extensive fibrosis in the center of the primary tumors. A few cancer cells, degenerated in various degrees, were found remaining in the periphery of the necrotic mass. Local side effects of the microspheres were skin disturbances such as pain, redness and blistering. ADM-ms was injected into the hepatic artery for the liver metastatic cases, and its antitumor effect was evaluated by CT scan or echography. Effective reduction in tumor size was only recognized in one case. No serious systemic side effects, not recognized in any case. Our report reviews the effectiveness of this therapy as a preliminary procedure for surgical treatment of inoperable inflammatory breast cancer.

Adult↗