Biomedical subjects
Publications and source records attributed to S Masuda.
A case of intestinal myiasis in an 8-month-old girl is reported. The clinical symptoms were ill humor and mucous bloody stools containing a number of moving worms, which were identified as second-instar larvae of Sarcophaga peregrina.
Genomes of many eubacterial strains have been shown to encode for multiple rpoD-related genes. In this report, we describe the identification of the multiple rpoD-related genes of cyanobacterial strains. DNAs of three cyanobacterial strains, Anabaena sp. PCC7120, Synechococcus sp. PCC7942, and Synechocystis sp. PCC6803, were examined by Southern hybridization, using a synthetic probe designed for detecting rpoD or rpoD-related genes. Four or five hybridization signals were found in each DNA. Four DNA regions of Synechococcus sp. PCC7942 corresponding to the hybridization signals were cloned and partially sequenced. The sequence data indicate the presence of genes, named rpoD1, rpoD2, rpoD3, and rpoD4, whose products are highly similar to the basic structure of the principal sigma factors of eubacterial strains. The rpoD1 gene showed the greatest similarity to the sigA gene of Anabaena sp. PCC7120.
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Patients with a paranasal disorder often manifest voice change. Yet, computer simulation of these nasal sounds is difficult using a nasal tract model without any branching cavity. In other words, acoustic property of the nasal tract is influenced by a coupling with the paranasal sinuses. If the transfer function of the sinus acts as a Helmholtz resonator, the resonance frequency, or "zero" point, of the sinus would be present on the acoustic spectrum of the nasal cavity. This study was designed to prove the validity of this hypothesis. The sweep tone was given from the subjects' epipharyngeal space. The tone passed through their nasal space and radiated from the anterior nostrils. In 13 cases without nasal or paranasal disorders, the tones obtained at the nostrils were analyzed with Fast Fourier Transformation (FFT) and were compared between two conditions of the ostia of the maxillary sinuses, obstructed and opened with epinephrine. The resonance frequencies of the maxillary sinuses ranged from 1 to 2 kHz and varied considerably among individuals. This variation may be due to a difference in the maxillary sinus volume and in the diameter and length of the natural maxillary ostium. In past reports, in which the resonance frequency of the sinus was measured using a compound model or computed simulation, the maxillary sinus resonated below 1 kHz. In these reports the ostium of the maxillary sinus was regarded as a straight pipe. However, the examination of 29 cadavers revealed that the radius of the ostium differs according to its depth. The radius in the depth halfway from the edge was narrower than that of the edge. The way of evaluating a shape of the ostium is different between the present and the past studies, thus possibly resulted in discrepancy of the resonance frequency.
Three cases of dumbbell neurogenic tumor of the posterior mediastinum are reported. None of these cases had any clinical symptoms, and an abnormal mass shadow of the mediastinum had been detected on routine chest roentgenogram. In these three cases, however, myelogram and/or CT findings were suggestive of tumor extension to the spinal canal in various degrees. Two tumors were resected in two-stage operations with combined thoracic and neurosurgical approaches, and the other case was treated by one-stage operation with the combined two approaches. All tumors were completely resectable without serious complications such as hemorrhage, leakage of spinal fluid, or neurologic deficit. Even in asymptomatic patients with neurogenic tumor located in the paravertebral region, it should be determined whether or not the tumor extends to the spinal canal through the intervertebral foramen, prior to planning the surgical procedure.
A 33-year-old male was admitted to our hospital because of an abnormal shadow in the right superior mediastinum on chest X-ray, which was first noted about half a year before his admission. Several diagnostic procedures, including fiber bronchoscopy, CT scan and MRI; however, no final diagnosis could be made. Thoracotomy was performed with the presumed diagnosis of benign mediastinal cystic tumor. Entry of the right thoracic duct into the cyst was observed at operation. Histological examination revealed that the cyst was lined by mono-layered cuboidal epithelial cells with lymphocytic infiltration in the wall of the cyst. The mono-layered cuboidal epithelium of the thoracic duct gradually changed to the epithelium of the cyst. Twenty ml of colorless transparent fluid was aspirated from the cyst. Analysis of aspirated fluid revealed low concentration of several substances except LDH compared to the values of the previously reported normal standards and other reported cases. From these findings, the cyst was diagnosed as mediastinal lymphatic cyst. Entry of the thoracic lymphatic duct into the mediastinal lymphatic cyst is a rare occurrence, and it is of interest to speculate on its relationship to the origin of the lymphatic cyst.
Erythropoietin (Epo) has three N-linked sugar chains. Codons for asparagine at N-glycosylation sites in genomic human Epo DNA were replaced with those for glutamine. The wild-type Epo gene and seven mutants that lacked N-glycosylation sites in every possible combination were introduced into baby hamster-kidney cells. To study the role of the N-linked sugars in Epo biosynthesis, Epo protein expressed transiently was measured by an enzyme-linked immunoassay. The elimination of all three N-glycosylation sites decreased Epo production to 10% of that of the wild-type Epo. Wild-type and mutant Epos produced by stably transfected cells were partially purified to investigate their properties. Removal of N-glycosylation sites changed affinity of Epo to the receptor. The in vitro activity of Epo that lost all N-glycosylation sites was comparable with that of the wild-type Epo, while the in vivo activity severely decreased. These results indicate that N-linked sugars of Epo have two major functions; N-linked sugars are important for 1) proper biosynthesis and/or secretion and 2) expression of the in vivo activity probably by enhancing survival in the circulation. N-Linked sugars of Epo affect binding affinity of the ligand to the receptor but do not play a key role in expression of the in vitro activity.
We examined the effect of transient forebrain ischemia of 2-, 3-, 4- and 5-min duration on the development of delayed neuronal death in field CA1 of the hippocampus in the gerbil whose brain temperature was maintained at 37 degrees C. Transient ischemia of 3- and 4-min duration caused almost the same maximal damage in field CA1 as observed in the gerbils subjected to 5-min ischemia. A detrimental factor inducing delayed neuronal death in field CA1 may be already set up during the first 3 min after the onset of ischemia in the gerbil whose brain temperature is maintained at normothermic levels.
Oxidation of the Met residues of human interleukin 6 (IL-6) molecule has been performed. Reactivity of Met for the oxidation reaction was found to decrease in the order of Met50, Met118, Met185, Met162, and Met68. Chemical modifications involving oxidation and carboxypeptidase A digestion of IL-6 have led to the assignments of the methyl proton resonances of Met162 and Met185, respectively. The hydroxynitrobenzyl chromophore attached to Trp158 in the IL-6 molecule showed a different absorption spectrum when the labeled IL-6 was bound to the soluble IL-6 receptor. This result indicates that Trp158 is near the receptor-binding region in IL-6. On the basis of the 1H-NMR and chemical modification data, it has been concluded that Trp158 is in spatial proximity to Met162, His165 and Met185. The receptor-binding activity decreased with an increase in the number of oxidized Met residues. Of these five Met residues, Met162 was the residue in which the receptor-binding activity decreased in the most parallel degree with that of the oxidation reaction.
The adhesion of staphylococcal protein A (SpA)-bearing Staphylococcus aureus Cowan I organisms to HeLa cells was enhanced by pretreatment of HeLa cells with staphylococcal extracellular antigens and antibodies to them. The adhesion of HLj, an SpA-poor mutant derived from Cowan I, to HeLa cells was not enhanced by the same pretreatment of HeLa cells. Furthermore, the enhanced staphylococcal adhesion was inhibited by soluble SpA. The antigen(s) responsible for the enhanced staphylococcal adhesion was(were) heat stable. Pretreatment of HeLa cells with the mixture of staphylococcal extracellular antigens and antibodies to them also enhanced the adhesion of Cowan I. Similarly the adhesion of Cowan I was enhanced by pretreatment of HeLa cells with extracellular antigens of Pseudomonas aeruginosa and antibodies to them. These results indicated that cell-bound SpA mediated the binding of S. aureus to immune complexes composed of extracellular bacterial products and antibodies to them bound to the surface of HeLa cells, and suggested another role of cell-bound SpA as a co-adhesin with other factors in infections due to S. aureus.
The effect of human recombinant erythropoietin (Epo) on B cell responses was studied in a serum-free medium. Epo enhanced IgM production and thymidine uptake by a human IgM-producing lymphoblastoid cell line, CBL. This effect was specific to Epo since enhancement was blocked by anti-Epo antibody but not by control antibody. Among the various cytokines, interleukin-4 (IL-4) enhanced IgM production and thymidine uptake while IL-6 enhanced IgM production without affecting thymidine uptake. In contrast, other cytokines including IL-1 beta, IL-2, IL-5, interferon-alpha (IFN-alpha), interferon-gamma (IFN-gamma), or granulocyte/macrophage colony-stimulating factor (GM-CSF) were without effect. However, the enhancing effect of Epo is different from that of IL-4 or IL-6, since Epo effect was not blocked by anti-IL-4 antibody or anti-IL-6 antibody. Moreover, specific binding of Epo was detected on CBL cells. Epo also enhanced immunoglobulin (IgG, IgM and IgA) production and thymidine uptake by purified tonsil small resting B cells stimulated by Staphylococcus aureus Cowan strain I (SAC) or by large activated B cells. In contrast, Epo had no effect on unstimulated small resting B cells. These results indicate that Epo could directly stimulate activated and differentiated B cells and could enhance B cell immunoglobulin production and proliferation.
Results of orcein staining and findings obtained with non-contrast-medium-enhanced computed tomography (CT) and magnetic resonance (MR) imaging (T1- and T2-weighted images) were compared for 53 histologically confirmed hepatocellular carcinomas (HCCs). HCCs were 5 cm in the largest diameter. Three lesions with diffuse and strong orcein staining were highly attenuating on nonenhanced CT images. Electron x-ray microanalysis of one of them revealed copper. The high attenuation value at nonenhanced CT may have been due to the abundant copper-binding protein in the cancer cells. The difference between orcein staining results and attenuation patterns at CT was statistically significant (chi 2, P less than .001). It could not be concluded that the paramagnetic effects of copper in HCC had an influence on signal intensity on MR images. The difference between orcein staining results and signal-intensity patterns on T1- and T2-weighted images was not statistically significant.
Five classes of serum immunoglobulin levels were investigated in 107 children with malignant or benign tumors. Hyperimmunoglobulinemia D (hyper-IgD) was observed in 31 of 82 children who were in complete remission off chemotherapy with a median follow-up of 4.5 years after cessation of chemotherapy. On the other hand, hyper-IgD was not found among 12 children with malignant or benign tumors treated with chemotherapy and a low incidence of hyper-IgD was observed during chemotherapy (1 of 13 cases). The result indicates that hyper-IgD is not uncommon in children off chemotherapy, suggesting that dysregulation of IgD synthesis persists long after cessation of antineoplastic drugs.
Cross-allergenicity between five cereal grains including rice, wheat, corn, Japanese millet (Panicum crus-galli L. var. frumentaceum Trin.) and Italian millet (Setaria italica Beauv. var. germanica schrad.) was examined by radioallergosorbent test (RAST) and RAST inhibition assay. There were significant close correlations between every combinations of RAST values for the five cereal grain extracts. RAST inhibition assay of each extract against RAST discs coupled with other cereal grain extracts indicated marked cross-reactivity of IgE binding between these cereal grain extracts. Rice protein 16KD (RP16KD) was shown to be one of major allergens in rice grain extracts by immunoblotting analysis, histamine release assay from human leukocytes and RAST inhibition. Next, the involvement of RP16KD in the cross-allergenicity between these cereals was investigated. RAST values for RP16KD significantly correlated with that for Italian millet as well as rice but not with those for corn and wheat. There was a trend of positive correlation between RAST values for RP16KD and Japanese millet. In the RAST inhibition assay using sera with positive RAST for these five cereal grain extracts and RP16KD, RP16KD inhibited IgE binding to these all cereal discs in a dose-dependent manner. Similarly, all of the five cereal grain extracts showed an effective decrease in IgE binding to the RP16KD disc. These results indicated possible participation of IgE binding structure on RP16KD in cross-allergenicity between these cereal grain extracts in the Poaceae family.
We describe an investigation of postoperative abdominal infectious complications and discuss two regimens for preoperative antibiotic bowel preparation in cases who underwent total cystectomy with ileal urinary diversion. Ten cases (28.6%) of 35 who had been operated developed abdominal infectious complications. Six showed abdominal wound infection, 2 showed intrapelvic abscess and 2 showed abdominal wound infection with intrapelvic abscess. Of the 19 strains of organisms isolated from the postoperative infections, 11 (57.9%) were anaerobic bacteria and the most commonly isolated bacteria was Bacteroides. A significantly lower incidence of postoperative infection was found in cases who had received tobramycin and vancomycin (0%) than in those who had received kanamycin alone (41.7%). These results indicate that anaerobic bacteria are the major contributors to postoperative infections following total cystectomy with ileal urinary diversion and that tobramycin-vancomycin prophylaxis greatly reduces the incidence of postoperative infections.
A novel vitamin D3 analogue, [2 beta-(3-hydroxypropoxy)-calcitriol: ED-71] showed a similar Ca-regulating activity as calcitriol in the in vivo and in vitro Ca mobilization test and ex vivo intestinal Ca absorption assay using vitamin D-deficient rats. The differentiation-inducing activity of ED-71 in mouse myeloid leukemia cell line (WEHI-3 cell) was slightly less than that of calcitriol. ED-71 distributes predominantly in plasma as an intact form and its half-life plasma was twice as long as that of calcitriol. Further study revealed that the higher binding potency of ED-71 to plasma-specific vitamin D-binding protein (DBP) compared with that of calcitriol accounts for its stability in the blood circulation. The pharmacological effect of ED-71 for the animal models with osteoporosis seemed to be better than that calcitriol. These results suggest that ED-71 should become a valuable therapeutic long-acting drug for patients with osteoporosis.
The binding potencies of OCT to chick intestinal calcitriol receptor and vitamin DBP were approximately 1/8 and 1/600 of the respective values of calcitriol. OCT is circulating mainly as an intact form bound to chylomicrons and/or lipoproteins. Intravenously injected [3H]-OCT to normal rats was quickly decreased from blood and rapid excretion of OCT as a glucuronate into bile was observed. However, significant amounts of radioactivities were recovered in the intact form in liver and intestine even after 24 h. The separation of calcemic and immune and/or differentiation activities may be derived from the rapid turnover and the nonspecific transporting system.