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Biomedical subjects

A Shimada

Publications and source records attributed to A Shimada.

At least 253 records · Page 14Linked to original sources
PubMed1991

Medullary bone of piglets.

The bone marrow is commonly present in the medullary cavity of long bones in most mammals at birth. In the present study, the persistence of the osseous tissue was examined in the medullary cavities of piglet bones at and after birth. Immediately after birth, medullary cavities of long bones were almost completely filled with the spongy bone. The persisted spongy bone, i.e., medullary bone was prominent in younger pigs but decreased with advance in age. By 90 days of age, the medullary bone almost disappeared to form the extended medullary cavity. During the disappearing process of the medullary bone, osteoclasts showed significant increase in size and number (p less than 0.05). In irregular and flat bones, osseous trabeculae of the medullary bone became slender with age. The extramedullary hematopoiesis in the liver and spleen was very active till 30 days of age. This may suggest that the persistence of the medullary bone narrows the medullary cavity to cause poor medullary hematopoiesis and is compensated by extramedullary hematopoiesis. The relationship among the medullary bone, extramedullary hematopoiesis and piglet anemia was discussed.

Aging↗
PubMed1991

Basic studies on visible light-curing resin for denture base. Part 8. The hardening depth of denture relining material after penetration of light through the denture base resin.

A study was performed to examine how the duration of irradiation at the time of relining with visible light-curing material influences the depth of hardening of the relining material, in relation to the thickness of the denture base placed between the denture and the relining material. It was found that for a range of denture base thickness of 1-2.5 mm, a desirable degree of hardening could be obtained using an irradiation time of 20 s for relining material with a thickness of up to 4 mm used for the basal surface.

Dental Materials↗
PubMed1991

The suppressive effect of anti-asialo GM1 antibody on low-dose streptozotocin-induced diabetes in CD-1 mice.

To elucidate the role of natural killer (NK) cells in the pathogenesis of diabetes in streptozotocin-induced diabetes, we examined whether treatment with anti-asialo GM1 antibody prevents the occurrence of diabetes in CD-1 mouse model. Anti-asialo GM1 antibody was injected intraperitoneally 2-3 times a week starting three days before the first streptozotocin injection. In controls, rabbit immunoglobulin or saline was injected instead of anti-asialo GM1 antibody. Three of twelve anti-asialo GM1 antibody-treated mice developed diabetes, however eight of eight (100%) rabbit immunoglobulin injected mice and 20 of 23 saline-injected mice developed diabetes. The incidence of diabetes in the anti-asialo GM1 antibody-injected group was significantly higher than in the two control groups (p less than 0.01, p less than 0.01, respectively). The NK-cell activities of spleen cells from anti-asialo GM1 antibody-treated mice were significantly lower than in control mice. Flow-cytometry analysis demonstrated that anti-asialo GM1 antibody-positive cells had disappeared from spleens of anti-asialo GM1 antibody-injected mice but no suppression of T-lymphocytes could be demonstrated. These results suggest that NK cells play a role in the pathogenesis of streptozotocin-induced diabetes in CD-1 mice.

Animals↗
PubMed1991

Anti-asialo GM1 antibody suppression of cyclophosphamide-induced diabetes in NOD mice.

To elucidate the role of natural killer (NK) cells in the pathogenesis of diabetes in the non-obese diabetic (NOD) mouse, we examined whether or not cyclophosphamide-induced diabetes occurs in NOD mice intraperitoneally (i.p.) injected with anti-asialo GM1 antibody. Two weeks after a single intraperitoneal injection of cyclophosphamide, none of the 24 NOD mice which had previously been treated with antiasialo GM1 antibody, 2-3 times per week for either 2 or 3 weeks, had developed indications of diabetes such as glycosuria or a high plasma glucose level. On the other hand, signs of diabetes were found in 10 of 24 control NOD mice injected with normal rabbit Ig instead of anti-asialo GM1 antibody (p less than 0.01). The NK cell activities of spleen cells from anti-asialo GM1 antibody-treated mice were significantly lower than those of control mice (p less than 0.01). Flowcytometry analysis demonstrated that anti-asialo GM1 antibody-positive cells had disappeared from the spleens of anti-asialo GM1 antibody-injected mice but no suppression of CD8+ and CD4+ cells could be demonstrated. These observations suggest that NK cells are involved in the development of diabetes in NOD mice.

Animals↗
PubMed1991

[Modified operation for an early stage gastric cancer].

The standard operation for gastric cancer is carried out for advanced gastric cancer with serosal invasion accompanying patent disseminative metastasis to the peritoneum of the omental bursa and lymph node metastases. It consists of subtotal or total gastrectomy, omentobursectomy and extended lymph node dissection. An early stage cancer, which in Japan accounts for almost a half of the resectable cases of gastric cancer, shows no serosal invasion, and lymph node metastases are rare if the cancer remains intramucosal. Such cases represent about a half the cases of the early stage cancer. The diagnosis of the early stage cancer, especially if it remains intramucosal, is made by means of preoperative radiological and endoscopic examinations and intraoperative examination. Since 1977 we have been performing a modified operation as well for cases of the early stage cancer. The surgical procedure is as follows: reduction in the size of gastric resection by 2/3, pylorus-preserving gastrectomy and proximal gastric resection; preservation of the distal portion of the greater omentum and transverse incision of the upper abdomen instead of upper midline incision to prevent ileus due to intestinal adhesion to abdominal wound around umbilicus; sparing bursectomy; narrowing the area of lymph node dissection; sparing thoracotomy for cancer in the esophagogastric junction; sparing splenopancreatectomy; preservation of the hepatic branch of the vagal nerve and postoperative temporary oral administration of cholagogue to prevent postgastrectomy cholelithiasis. In addition, the primary lesion is isolated from the blood circulation by means of ligation of the drainage veins to diminish metastasis through the blood vessels (hepatic metastasis, etc.), which is the main cause recurrence after surgery for the early stage cancer. The results of this new surgery are satisfactory; the five-year postoperative survival rate is 100.0% and it reduced the time needed for surgery, anesthesia and blood transfusion.

Humans↗
PubMed1991

Myocardial infarction secondary to a disseminated coagulopathy in a cow.

A 3-year-old Holstein cow was presented with a history of high fever, jaundice and subsequent recumbency. The animal died 3 hours after arrival at our department; continuous electrocardiographic examination was performed during those last 3 hours. There were ventricular premature beats (VPBs) with high frequency and complex patterns (bigeminal, trigeminal, repetitive or early cycle VPBs) and paroxysms of ventricular tachycardia (VT). Serum CK-MB was markedly elevated. On histopathological examination, large areas of myocardial necrosis were found in the anterior aspects of the left ventricle. Large, partially organized thrombi occluded the intramural coronary arteries within and adjacent to the lesion. From the histopathological findings, it appeared that a disseminated coagulopathy caused the thromboembolism in the intramural coronary arteries, resulting in acute myocardial infarction (AMI). Various clinical findings, such as arrhythmias, were similar to those in man.

Animals↗
PubMed1991

Effect of intraperitoneal administration of heparin to patients on continuous ambulatory peritoneal dialysis (CAPD).

The effect of intraperitoneal administration of heparin to patients on continuous ambulatory peritoneal dialysis (CAPD) remains obscure. We examined 8 patients on CAPD to investigate its effect. When 2.5 U/ml or 5 U/ml of heparin was given intraperitoneally, t1/2 of heparin activity in the dialysate was 0.5 to 2 hrs, and 6 hrs after administration its activity was 0.5 U/ml and 1.4 U/ml respectively. Whole blood clotting time was hardly affected because the transfer of heparin to the plasma was minimal. The plasma antithrombin III (AT-III) levels were comparable to patients on hemodialysis, but the AT-III level in the dialysate was only 1.5% of those in the plasma. We conclude that the intraperitoneal administration of heparin at these doses is effective in preventing fibrin precipitation when intraperitoneal AT-III levels are expected to be relatively increased such as at the start of CAPD or in the presence of peritonitis.

Adult↗
PubMed1990

Ovine ceroid-lipofuscinosis is a proteolipid proteinosis.

The pathogenesis of the ceroid-lipofuscinoses, inherited storage diseases of children, was studied in an ovine model. This was shown to have clinical and pathological features most in common with the late infantile and juvenile human forms of the disease. The ability to study sequential changes allowed the retinal lesions to be described as a dystrophy of photoreceptor outer segments which preceded loss of the photoreceptor cells. An early decrease in amplitude of the c-wave electroretinograph was attributed to a decrease in the transpigment epithelial component. The decreased a- and b-wave amplitudes were attributed to the changes in and loss of, photoreceptor cells. The chemical components of isolated storage cytosomes were analyzed and shown to consist mostly of protein. Sequence analysis of the dominantly stored protein showed that it was identical to the DCCD reactive proteolipid or subunit c of mitochondrial adenosine triphosphate synthase and that it comprised approximately 50% of storage material. Based on the adage that the dominantly stored species should reflect the underlying biochemical anomaly, it was concluded that it was of pathogenic significance. This highly hydrophobic protein tends to extract with lipids in chloroform/methanol and is thus known as a proteolipid. Some of the remainder of the stored proteins also had this characteristic. It was concluded that ovine ceroid-lipofuscinosis was a proteinosis, more specifically a proteolipid proteinosis and as such it forms the prototype of a new class of storage diseases. Recognition of the nature of the dominantly stored chemical species has helped understanding of a variety of chemical and physical characteristics attributed to the whole pigment.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1990

Fluorometric examination of tissue amyloid fibrils in murine senile amyloidosis: use of the fluorescent indicator, thioflavine T.

Thioflavine T, a fluorescent indicator of amyloid fibrils (Naiki H, Higuchi K, Hosokawa M, Takeda T: Anal Biochem 177:244, 1989), has been tested in unfractionated tissue homogenates. With 250 nM thioflavine T, liver homogenates from a 17-month-old SAM-P/1 (senescence accelerated mouse-prone), which contained amyloid fibrils in murine senile amyloidosis (fASSAM) fluoresced brightly, whereas normal liver homogenates showed a negligible fluorescence. The following evidence confirmed that the fluorescence in the unfractionated preparations specifically represented fASSAM. The fluorescence of fASSAM deposited liver tissue was diminished to the level of the normal liver when the structure of the amyloid fibrils was disrupted by guanidine-HCl. Second, about 90% of the fluorescence of fASSAM deposited liver tissue was fractionated in the water-soluble fraction, in which amyloid fibrils are generally enriched. We then determined the concentration of fASSAM in the tissue, from the fluorescence and using the standard curve described in the above mentioned report. Lower limits of fASSAM determination were about 1 microgram/mg of tissue. A marked regional heterogeneity of fASSAM deposition was observed in the liver. We observed a linear correlation between fASSAM concentration and percentage of amyloid positive area in the liver. Age-dependent increases in fASSAM concentrations and total fASSAM contents were noted in the liver and spleen of 11 to 15-month-old SAM-P/1. There was also a positive correlation between the organ weight and fASSAM concentrations in both organs. Thus, thioflavine T is of practical use for the determination of fASSAM concentrations in the tissue.

Aging↗
PubMed1990

[Intraperitoneal administration of anti-cancer drug with cisplatinum (CDDP)].

Six patients were administered cisplatinum (CDDP) i.p. There were four cases with peritoneal dissemination of gastric cancer after gastrectomy and the other two, for whom prophylactic intraperitoneal administration of CDDP had been attempted to prevent peritoneal metastasis. The dose of CDDP was 75-140 mg/body (58-90 mg/m2). The results were 1 PR, 2 NC and 1 PD. The PR case was given intraperitoneal CDDP combined with RF thermotherapy. Liver dysfunctions, renal dysfunctions, bone marrow suppressions, and GI tract disturbances were observed as toxic reactions. The degrees of side effects after i.p. administration were less severe than after i.v. administration. However the indication of CDDP i.p. administration should be decided after case conferences. On pharmacokinetics, non-protein bound platinum was detected at 24 hours after i.p. administration, in ascites and plasma. The concentration of platinum in ascites was about three-fold than in plasma. It was considered that CDDP absorption from ascites into plasma depended on the state of peritoneal dissemination of cancer.

Adult↗
PubMed1989

The complete sequence of soybean chlorotic mottle virus DNA and the identification of a novel promoter.

The complete nucleotide sequence of an infectious clone of soybean chlorotic mottle virus (SoyCMV) DNA was determined and compared with those of three other caulimoviruses, cauliflower mosaic virus (CaMV), carnation etched ring virus and figwort mosaic virus. The double-stranded DNA genome of SoyCMV (8,175 bp) contained nine open reading frames (ORFs) and one large intergenic region. The primer binding sites, gene organization and size of ORFs were similar to those of the other caulimoviruses, except for ORF I, which was split into ORF Ia and Ib. The amino acid sequences deduced from each ORF showed only short, highly homologous regions in several of the corresponding ORFs of the three other caulimoviruses. A promoter fragment of 378 bp in SoyCMV ORF III showed a strong expression activity, comparable to that of the CaMV 35S promoter, in tobacco mesophyll protoplasts as determined by a beta-glucuronidase assay using electrotransfection. The fragment contained CAAT and TATA boxes but no transcriptional enhancer signal as reported for the CaMV 35S promoter. Instead, it had sequences homologous to a part of the translational enhancer signal reported for the 5'-leader sequence of tobacco mosaic virus RNA.

Amino Acid Sequence↗
PubMed1989

Closed and continuous algae cultivation system for food production and gas exchange in CELSS.

In CELSS (Controlled Ecological Life Support System), utilization of photosynthetic algae is an effective means for obtaining food and oxygen at the same time. We have chosen Spirulina, a blue-green alga, and have studied possibilities of algae utilization. We have developed an advanced algae cultivation system, which is able to produce algae continuously in a closed condition. Major features of the new system are as follows. (1) In order to maintain homogeneous culture conditions, the cultivator was designed so as to cause a swirl on medium circulation. (2) Oxygen gas separation and carbon dioxide supply are conducted by a newly designed membrane module. (3) Algae mass and medium are separated by a specially designed harvester. (4) Cultivation conditions, such as pH, temperature, algae growth rate, light intensity and quantity of generated oxygen gas are controlled by a computer system and the data are automatically recorded. This equipment is a primary model for ground experiments in order to obtain some design data for space use. A feasibility of algae cultivation in a closed condition is discussed on the basis of data obtained by use of this new system.

Biomass↗
PubMed1989

Structure and glycosylation of lipoteichoic acids in Bacillus strains.

The occurrence, structure, and glycosylation of lipoteichoic acids were studied in 15 Bacillus strains, including Bacillus cereus (4 strains), Bacillus subtilis (5 strains), Bacillus licheniformis (1 strain), Bacillus polymyxa (2 strains), and Bacillus circulans (3 strains). Whereas in the cells of B. polymyxa and B. circulans neither lipoteichoic acid nor related amphipathic polymer could be detected, the cells of other Bacillus strains were shown to contain lipoteichoic acids built up of poly(glycerol phosphate) backbone chains and hydrophobic anchors [gentiobiosyl(beta 1----1/3)diacylglycerol or monoacylglycerol]. The lipoteichoic acid chains of the B. licheniformis strain and three of the B. subtilis strains had N-acetylglucosamine side branches, but those of the B. cereus strains and the remaining two B. subtilis strains did not. The membranes of the B. licheniformis strain and the first three B. subtilis strains exhibited enzyme activities for the synthesis of beta-N-acetylglucosamine-P-polyprenol and for the transfer of N-acetylglucosamine from this glycolipid to endogenous acceptors presumed to be lipoteichoic acid precursors. In contrast, the membranes of the other strains lacked both or either of these two enzyme activities. The correlation between the occurrence of N-acetylglucosamine-linked lipoteichoic acids and the distribution of these enzymes is consistent with the previously proposed function of beta-N-acetylglucosamine-P-polyprenol as a glycosyl donor in the introduction of alpha-N-acetylglucosamine branches to lipoteichoic acid backbone chains.

Bacillus↗
PubMed1989

Function of alpha-D-glucosyl monophosphorylpolyprenol in biosynthesis of cell wall teichoic acids in Bacillus coagulans.

D-[alpha-14C]]glucosyl phosphorylpolyprenol ([ 14C]Glc-P-prenol) was formed from UDP-D-[14C]glucose in each of the membrane systems obtained from Bacillus coagulans AHU 1631 and AHU 1634 and two Bacillus megaterium strains. Membranes of these B. coagulans strains, which possess beta-D-glucosyl branches on the repeating units in their major cell wall teichoic acids, were shown to catalyze the transfer of the glucose residue from [14C]Glc-P-prenol to endogenous polymer. On the other hand, membranes of B. coagulans AHU 1366, which has no glucose substituents in the cell wall teichoic acid, exhibited neither [14C]Glc-P-prenol synthetase activity nor the activity of transferring glucose from [14C]Glc-P-prenol to endogenous acceptor. The enzyme which catalyzes the polymer glycosylation in the former two B. coagulans strains was most active at pH 5.5 and in the presence of the Mg2+ ion. The apparent Km for [14C]Glc-P-prenol was 0.6 microM. Hydrogen fluoride hydrolysis of the [14C]glucose-linked polymer product yielded a major fragment identical to D-galactosyl-alpha(1----2)(D-glucosyl-beta(1----1/3)) glycerol, the dephosphorylated repeating unit in the major cell wall teichoic acids of these B. coagulans strains. This result, together with the behavior of the radioactive polymer in chromatography on Sepharose CL-6B, DEAE-Sephacel, and Octyl-Sepharose CL-4B, led to the conclusion that [14C]Glc-P-prenol serves as an intermediate in the formation of beta-D-glucosyl branches on the polymer chains of cell wall teichoic acids in B. coagulans.

Bacillus↗
PubMed1988

The function of beta-N-acetyl-D-glucosaminyl monophosphorylundecaprenol in biosynthesis of lipoteichoic acids in a group of Bacillus strains.

Membrane preparations, obtained from Bacillus strains which have N-acetylglucosamine-linked lipoteichoic acids in their membranes, were shown to catalyze the transfer of N-[14C]acetylglucosamine (GlcNAc) from beta-[14C]GlcNAc-P-undecaprenol to endogenous polymer. In this reaction, alpha-GlcNAc-P-undecaprenol or alpha-GlcNAc-PP-undecaprenol could not substitute for beta-GlcNAc-P-undecaprenol as the N-acetylglucosamine donor. This enzyme was most active at pH 6.0 and in the presence of 40 mM MgCl2. The apparent Km for beta-GlcNAc-P-undecaprenol was 2 microM. The radioactive polymer products, solubilized by hot phenol treatment, coincided with lipoteichoic acids in chromatographic behavior. Hydrogen fluoride treatment of the polymer products gave a major fragment identical with GlcNAc(alpha 1----2)glycerol, which corresponded to the dephosphorylated repeating units of the lipoteichoic acids in the examined strains. Thus it is concluded that beta-GlcNAc-P-undecaprenol serves as the donor of N-acetylglucosamine in the biosynthesis of lipoteichoic acids in a group of Bacillus strains.

Bacillus↗