Biomedical subjects
Publications and source records attributed to A Masuda.
Patients with Treacher Collins syndrome pose a serious problem to anaesthetists in maintaining their airway because of retrognathia. Two patients with Treacher Collins syndrome undergoing tympanoplasty are reported in whom a laryngeal mask was used in place of an endotracheal tube for airway maintenance.
The influence of cell density on the binding characteristics of thromboxane A2/prostaglandin H2 (TXA2/PGH2) receptors in rat aortic vascular smooth muscle cells in culture were determined using [1S- (1 alpha, 2 beta (5Z), 3a (1E, 3R*), 4 alpha)]- 7 -[3- (3-hydroxy -4- (4'-iodophenoxy)-1-butenyl)-7-oxabicyclo-[2.2.1]heptan- 2yl]-5-heptenoic acid (125I-BOP). The Bmax for 125I-BOP was 5,430 +/- 139 sites/cell (26.9 +/- 5.7 fmoles/mg protein) for cells cultured in 1% fetal calf serum and 2809 +/- 830 sites/cell (13.1 +/- 2.2 fmoles/mg protein) for cells cultured in 10% fetal calf serum. Cells were allowed to grow to varying densities and then harvested for assay. There was a negative correlation between the Bmax and the cell density per flask. The Kd for I-BOP did not significantly vary in any of the studies. The results demonstrate that cell density plays an important role in influencing the expression of vascular TXA2/PGH2 receptors.
Published data on the mutagenicity of 3 bile acids in the bacterial fluctuation test are conflicting. Eleven 5 beta-cholanoic acids including 2 of the bile acids were assayed for mutagenicity in Salmonella typhimurium TA98 and TA100 in the fluctuation tests. In any of these bile acids at the doses tested, there were no dose-related statistically significant increases in mutagenicity compared with appropriate controls. Similarly, none of these compounds showed positive mutagenicity in both strains in the standard Ames test either with or without hepatic metabolic activation. Our results support the claim that 3 bile acids are not mutagenic, and indicate that the initiation activity of 5 beta-cholanoic acids is not demonstrable with a short-term assay using Salmonella strains.
Babesia bovis is an intraerythrocytic protozoan that causes bovine babesiosis. Agarose gel electrophoresis of nucleic acids extracted from two isolates of B. bovis reveals, besides bulk DNA, an ethidium bromide-stainable band at about 5.5 kb. Further characterization of the latter with DNase I, RNase and mung bean nuclease suggested it to be a double-stranded RNA. Sonicated parasites were fractionated in a CsCl buoyant density gradient. A sample containing the 5.5-kb RNA was analysed under an electron microscope and a virus-like particle was observed.
Radiofrequency catheter ablation of the atrioventricular (AV) node or bundle of His was performed in 12 adult mongrel dogs. The aim was to create chronic incomplete AV block (first- and second-degree AV block) and to examine the histopathology of the ablated lesions. However, the late electrophysiological results (2-4 weeks follow-up) were various: normal in 2 dogs, mild PR prolongation (less than 50%) in 2 dogs, first-degree AV block (PR prolongation greater than or equal to 50%) in 2 dogs, second-degree AV block in 2 dogs, complete AV block in 4 dogs. The maximally ablated area (%) of the atrioventricular conduction system in serial histologic sections from dogs with these conditions was 69%, 75%, 89.5%, 95% and 99.5%, respectively. The number of intact conduction cells at the maximally ablated site varied from 6 to 30 in the four cases of incomplete AV block. The mean ablated volume (%) of either the AV node or penetrating His bundle correlated roughly with the degree of AV block. The ablated lesions were well demarcated and almost replaced by dense fibrous tissue at 4 weeks. Interruption (3 dogs) or thinning (1 dog) of the endocardial elastic lamellae was detected, in association with endocardial thickening (mean 913 microns). Endocardial thrombi were found in 3 dogs (2 fresh, 1 organized). We conclude that radiofrequency catheter ablation does not cause severe complicated lesions. Several possible conditions for creating chronic incomplete AV block are discussed.
Previous studies have demonstrated increased contractile responses to thromboxane A2 (TXA2) mimetics in aortas obtained from male rats compared with those obtained from females. This study was designed to determine the effects of testosterone and 17 beta-estradiol treatment on TXA2 receptors in cultured rat aortic smooth muscle cells (RASMCs). TXA2 receptor affinity and density were determined through equilibrium binding experiments using the TXA2/prostaglandin H2 mimetic [1S-(1 alpha,2 beta(5Z),3 alpha(1E,3R*),4 alpha)]-7-[3-(3- hydroxy-4-(4'-125iodophenoxy)-1-butenyl)-7-oxabicyclo[2.2.1]hep tan-2-yl]- 5-heptenoic acid (125I-BOP). Incubation with testosterone (100 nM) for 24 or 48 hours resulted in a significant (p less than 0.05) 31% and 48% increase in TXA2 receptor density without any change in affinity. 17 beta-Estradiol (100 nM) had no significant effect on either the density or affinity of TXA2 receptors. Coincubation with the testosterone receptor antagonist hydroxyflutamide (1 microM) blocked the testosterone-induced increase in TXA2 receptor density. The maximum increase in intracellular free calcium induced by I-BOP was significantly (p less than 0.05) greater in testosterone-treated RASMCs than controls. Similarly, increases in inositol trisphosphate induced by the TXA2/prostaglandin H2 mimetic U46619 were significantly (p less than 0.05) greater in testosterone-treated RASMCs compared with controls. The results demonstrate that testosterone increases vascular TXA2 receptor density and support the notion that sex steroid hormones modulate the expression of this receptor.
A (1-3)-beta-D-glucan, grifolan (GRN), recovered from the peritoneal cavity after 1 d from i.p. injection contained a significant amount of anionic metabolite(s) having lower Mr than the parent GRN. In parallel with this observation, GRN induced peritoneal exudate cells exhibiting a higher level of oxidative burst than the non-stimulated, resident peritoneal cells. Chemical oxidation of GRN by active oxygen species such as (a) ascorbic acid-CuSO4, (b) hydrogen peroxide, (c) hydrogen peroxide-CuSO4, or (d) hypochlorous acid also produced anionic as well as lower Mr degradation products. Under these experimental conditions the structural changes were remarkable and in the order of a less than b less than c less than d. The products formed under the conditions (a) and (b) retained significant antitumor activity but those of (c) and (d) lost the activity. However, oxidation product(s) of curdlan, an antitumor inactive (1-3)-beta-D-glucan having no branch, by condition (d) induced significant antitumor activity. These results suggested that oxidative degradation of (1-3)-beta-D-glucans produced some temporary active metabolites and then gradually changed to the inactive form. However, these active metabolites contribute less than the parent glucan on the whole activation mechanisms of the host by (1-3)-beta-D-glucans.
The inhibitory effect on experimental pulmonary metastasis of Lewis lung carcinoma (3LL) of SSG, a (1----3)-beta-D-glucan obtained from the fungus Sclerotinia sclerotiorum IFO 9395, administered orally was examined in mice. Oral administration of SSG for 10 consecutive days just after the intravenous implantation of tumor cells significantly inhibited the experimental pulmonary metastasis of 3LL at a dose of 2000 micrograms. However, SSG administered orally involving other timings was less effective. In comparison with oral administration, SSG was effective when administered intraperitoneally for 10 consecutive days at a dose of 200 micrograms. These results suggest that SSG given by both parenteral and nonparenteral routes is effective in the inhibition of experimental pulmonary metastasis of tumors.
The effect of intraperitoneally (i.p.) administered SSG, a beta-1,3-glucan obtained from the culture filtrate of the fungus Sclerotinia sclerotiorum IFO 9395, on the functions of alveolar macrophages (AM) in CDF1 mice was examined. SSG administered i.p. increased the number of AM and enhanced several functions of murine AM (lysosomal enzyme activity, phagocytic activity, candidacidal activity, H2O2 production and interleukin 1 (IL-1) production) at a dose of 250 micrograms/mouse on days 1 and 8, especially on day 8. Furthermore, SSG (250 micrograms/mouse) administered i.p. for 10 consecutive days significantly inhibited the experimental pulmonary metastasis of Lewis Lung Carcinoma (3LL) on BDF1 mice.
A time course of cardiovascular activity in 8 healthy males in relation to augmented ventilatory activity and humoral factors was observed during step CO2 elevation with constant hypoxia. During the first step increase, by 3 Torr in end-tidal PCO2 (PETCO2), the heart rate (HR) initially tended to decrease, then slowly increased to slightly below that of the previous eucapnic level, whereas ventilation maintained a gradual rise throughout this period. On the other hand, during second step PETCO2 elevation, by a further 3 Torr, both HR and ventilation progressively increased. The plasma catecholamine (CA) concentration was also significantly elevated during this period, suggesting a concomitant enhancement in sympathetic activity. Blood pressure (Bp) was progressively augmented throughout the entire hypoxic challenge. We conclude that 1) the characteristic profile of HR change may be explained by the observation that initial HR depression by peripheral chemoreceptor stimulation is gradually overridden by delayed hyperventilation, CA elevation, and enhanced sympathetic activity; 2) Bp augmentation may be elicited by increased CA release and sympathetic activity; and 3) plasma K+ concentration does not change so as to affect cardiovascular and respiratory activity.
Cardiac output (Q), stroke volume (SV), heart rate (HR), and respiratory variables were measured in ten healthy men performing static, isometric muscular contraction (handgrip) during air breathing. We found an instantaneous rise in ventilation (VI) and in HR, accompanied by a minimal rise in cardiac output. The rise in VI was due to a rise in tidal volume (VT) and a reduction in expiratory duration (TE). These effects of isometric exercise are explainable as due to a muscle reflex instantly inhibiting the cardiac, vagal motoneurons and, at the same time, stimulating neurons in the respiratory area of the medulla. These medullary neurons seem capable of independent operation. The rise in mean arterial pressure (MAP) during isometric exercise is 27% just as the rise in total peripheral vascular resistance (TPVR). The MAP rise is too high to be caused by vascular occlusion due to the high tension of contracted muscles in only one upper extremity. Thus, redistribution of Q in the system of many parallel vascular resistances is a likely possibility--with possible cutaneous vasodilation and dominating vasoconstriction of other vascular regions.
Clinical results of cases of hypopharyngeal carcinoma treated from 1966 to 1990 at Kyushu University Hospital were investigated. In 1966-1972, all cases were treated with only radical operation. We used FAR therapy since 1972, and preoperative chemotherapy (CDDP and Peplomycin) in addition to FAR therapy since 1984. The crude five-year survival rate of the operative therapy-group (25 cases in 1966-1972) was 24%, and that of the FAR therapy-group with or without operation (47 cases in 1972-1980) was 38%. Although it was cumulative survival rate by Kaplan-Meier's method, the five-year survival rate of the group (16 cases in 1984-1990) treated with a combination of FAR therapy, preoperative-chemotherapy, and operation was 76%. The improvement in the survival rate and the role of preoperative treatment (FAR therapy and chemotherapy) are discussed.
A case of giant müllerian duct cyst is reported. The patient was a 27-year-old male, complaining of microscopic hematuria. A giant cystic abdominal mass was palpable. After screening examination including ultrasound tomography, intravenous pyelography, computed tomography and magnetic resonance-imaging, müllerian duct cyst was suspected. Operation for this cyst was performed with median incision. The cyst measured 25 x 21 x 14 cm. The surface as smooth and consistency was soft. Included fluid was slightly turbid and yellowish measuring 2,200 ml. This was considered to be the largest müllerian duct cyst case reported in the Japanese literature.
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We sought to clarify the mechanisms of growth hormone (GH) secretion induced by insulin hypoglycemia, L-dopa, and arginine in man. The secretion of GH as measured by increased plasma level, in response to oral administration of 500 mg L-dopa or 30 min-infusion of arginine, was not modified by prior intravenous administration of 200 micrograms GH-releasing hormone (GHRH). It was, however, completely blocked by preadministered 50 micrograms SMS201-995, a long-acting somatostatin (SRIH) analog. GH release with 200 micrograms GHRH was completely blocked by 100 micrograms SMS201-995. GH secretion caused by insulin-induced hypoglycemia was significantly reduced but still present after administration of 100 micrograms of the analog. These results suggest that a suppression of SRIH release may be partially involved in the stimulatory mechanism of GH secretion by L-dopa. Coadministration of GHRH accentuated the stimulatory effect of arginine on GH secretion. Arginine significantly raised plasma TSH levels. These findings suggest that arginine suppresses SRIH release from the hypothalamus to cause GH secretion because SRIH suppresses TSH secretion. It is also suggested that some factor (or factors) other than GHRH and SRIH are involved in the mechanism by which insulin-induced hypoglycemia stimulates GH secretion, because the effect of insulin was not fully blocked in the presence of SRIH analog. Thus all the tests for GH release appear to act via different mechanisms.
The structure activity relationship for beta-D-glucans for the gelation of the amoebocyte lysates of the horseshoe crab (Limulus) has been investigated. beta-D-Glucans that had no (1----3) linkages induced little or no gelation. The (1----3)-beta-D-glucans curdlan (unbranched), grifolan (approximately 33% branched), schizophyllan (approximately 33% branched), lentinan (approximately 40% branched). SSG (approximately 50% branched), and OL-2 (approximately 66% branched) induced significant gelation. The optimum concentration for gelation was correlated with the content of branching. Single chain (rather than a triple helix) conformation and higher molecular weight were associated with higher reactivity.
When HeLa cells were exposed to heat shock or other stresses, a 40-kDa protein (p40) was induced in addition to the classical heat shock proteins with molecular sizes of 110-, 90-, 70-, and 47-kDa. The p40 was induced not only by heat shock but by arsenite and 2-azetidine carboxylic acid. Also, it was induced in rat, mouse and chick cells by these stresses. The p40 was a basic protein (pI divided by 9.2) as judged by two-dimensional gel electrophoresis. To our knowledge, p40 is a novel heat shock protein in mammalian and avian cells.
Seven clonal epithelial cell lines from a thymoma of an (ACI/NMs x BUF/Mna)F1 rat and seven clonal epithelial cell lines from an ACI/NMs rat thymus were established in a medium containing 1 microM dexamethasone (DM) and were characterized cytologically. Long-term treatment of DM stabilized the epithelial nature of these epithelial cells irreversibly. The established cell lines showed a polygonal shape, were positively stained with antikeratin antiserum and had tonofilaments and desmosomes. Species of their keratin peptides were the same as those of normal thymic epithelial cells in primary cultures. The cell lines were positively stained with Th-4 monoclonal antibody which preferentially stains the medullary epithelial cells of the thymus, but not with Th-3 which preferentially stains the subcapsular and cortical epithelial cells of the thymus. The cells from the rat thymoma were much larger than those from the normal thymus, as reflected in their primary cultures. No transformed phenotypes, such as high growth rate, high saturation density, anchorage independency, low serum dependency and so on, were found in the cell lines from the thymoma as in the cell lines from the normal thymus by in vitro assays. DNA synthesis of the thymic lymphocytes was stimulated by culturing with a line of rat thymoma with no lectins. Thymic lymphocytes strongly bound on the cell lines from the thymoma and changed the shape of the cells. These cell lines may be useful to investigate the mechanism of thymomagenesis and the interactions between epithelial cells and thymocytes in the rat thymoma.