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Biomedical subjects

S Sawamura

Publications and source records attributed to S Sawamura.

At least 19 recordsLinked to original sources
PubMed1995

The bipotential glial progenitor cell line can develop into both oligodendrocytes and astrocytes in the mouse forebrain.

Oligodendrocyte-type 2 astrocyte (O2A) progenitor cells in vivo might differentiate into oligodendrocytes. To examine the influence of the brain micro-environment on the differentiation, a bipotential glial cell line from the mouse cerebrum, designated OS3 cells, was implanted into the telencephalon of infant and adult mice. About a half of the OS3 cells injected into 1-week postnatal brain expressed galactocerebroside (GalC), and even myelin basic protein, which were not observed to be expressed in vitro. By contrast, in the brain over 6 months postnatally, many OS3 cells expressed glial fibrillary acidic protein, and did not express much GalC. These findings suggest that the differentiation of glial cells is controlled by stage specific factors in the brain.

Animals↗
PubMed1994

Growth inhibition of Clostridium difficile by intestinal flora of infant faeces in continuous flow culture.

Growth of Clostridium difficile was inhibited more strongly in continuous flow (CF) culture with C. difficile-negative faeces of infants than with C. difficile-positive faeces. Culture of faecal flora of infants yielded a greater variety of bacterial species in C. difficile-negative than in C. difficile-positive faeces. In the mixed CF culture of C. difficile with Enterococcus avium, Bacteroides distasonis, Eubacterium lentum, C. ramosum, C. perfringens and either Escherichia coli or Klebsiella pneumoniae isolated from C. difficile-negative faeces, inhibition of growth of C. difficile was demonstrated when the pH of the culture medium was decreased. Amino-acid analysis of CF cultures showed considerable utilisation of aspartic acid, serine, threonine, arginine and asparagine. A marked increase in concentrations of citrulline and ornithine was found in the culture that inhibited growth of C. difficile. The addition of citrulline and ornithine into a Gifu anaerobic medium (GAM) broth produced no inhibition of growth of C. difficile. The addition of the mixture of the depleted amino acids (aspartic acid, serine, threonine, arginine and asparagine) to the culture filtrate or adjustment of the pH of the culture filtrate induced considerable growth of C. difficile. These results suggest that the inhibition of growth of C. difficile may be due to consumption of amino acids by intestinal flora, and not to the presence of inhibitors produced by the intestinal flora.

Amino Acids↗
PubMed1994

Biochemical analysis of prostate specific antigen-proteolyzed insulin-like growth factor binding protein-3.

Prostate specific antigen (PSA) has been shown to proteolyze IGFBP-3. However, the cleavage sites and mechanism of proteolysis are unknown. In this study, we proteolyzed recombinant human IGFBP-3 with PSA bound to a solid phase support. The reaction mixture was separated by centrifugation, with PSA remaining in the solid phase and the proteolyzed IGFBP-3 in the aqueous phase. The IGFBP-3 fragments were functionally analyzed by affinity labeling and Western ligand blotting (WLB). Further biochemical analyses were provided by silver staining of total protein and Western immunoblotting (WIB) of immunoreactive fragments with an IGFBP-3 specific antiserum (alpha-BP-3 g1). N-terminal sequence analysis was performed on filter-immobilized IGFBP-3 fragments, following size separation by SDS-polyacrylamide electrophoresis. PSA proteolyzed IGFBP-3 into at least 7 fragments (M(r) of 26 kDa to 13 kDa) as identified by silver staining and WIB. At least 3 fragments were visible by affinity labeling with radiolabeled IGF-I or IGF-II and 4 were weakly visible by WLB. These data indicate that some IGFBP-3 fragments retain their ability to bind IGF. N-terminal sequence analysis revealed at least 5 different proteolytic recognition sites for PSA in IGFBP-3. Three of the 5 sites were consistent with a 'kallikrein-like' enzymatic activity and 2 sites were consistent with a 'chymotryptic-like' enzymatic activity. The chymotryptic activity of PSA was further confirmed by the ability of alpha-1-antichymotrypsin and chymostatin to block PSA cleavage of radiolabeled IGFBP-3.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Analysis of intestinal flora of a patient with congenital absence of the portal vein.

A 14-year-old female patient, admitted for a closer examination of liver tumour (hepatocellular adenoma), was diagnosed as having a congenital absence of the portal vein. The blood ammonia level (approximately 120 micrograms dl-1) in the superior mesenteric vein was markedly low compared to the normal value of 300-350 micrograms dl-1 in the portal vein. The decreased ammonia concentration and urease activity of the patient's faeces were demonstrated. The dominant intestinal flora in the faeces of the patient, before operation, was Bifidobacterium sp., Bifidobacterium breve, Bifidobacterium lonqum, Lactobacillus plantarum, and after the operation Bacteroides vulgatus, Veillonella parvula, Peptococcus magnus Bifidobacterium longum. In contrast, Bifidobacterium bifidum, Bacteroides ureolyticus, Bacteroides ovatus and Bacteroides distasonis, B. ovatus, Bifidobacterium adolescentis were dominant flora in the faeces of two healthy volunteers, respectively. Among microorganisms isolated from the patient, Morganella morganii, Candida sp., Eubacterium aerofacience and Eubacterium rectale were strongly positive in urease activity in vitro; Streptococcus mitior, Staphylococcus intermedius, Micrococcus kristinae, Selenomonas ruminantum, Bacteroides ureolyticus and Lactobacillus casei ss. pseudoplantarum from the healthy volunteers. These results imply the homeostatic regulation system of faecal ammonia concentration by urease-producing microorganisms in the patient.

Adolescent↗
PubMed1992

The alpha-helix to beta-sheet transition in poly(L-lysine): effects of anesthetics and high pressure.

Poly(L-lysine) exists in a random-coil formation at a low pH, alpha-helix at a pH above 10.6, and transforms into beta-sheet when the alpha-helix polylysine is heated. Each conformation is clearly distinguishable in the amide-I band of the infrared spectrum. The thermotropic alpha-to-beta transition was studied by using differential scanning calorimetry. At pH 10.6, the transition temperature was 43.5 degrees C and the transition enthalpy was 170 cal/mol residue. At pH 11.85, the measurements were 36.7 degrees C and 910 cal/mol residue, respectively. Volatile anesthetics (chloroform, halothane, isoflurane and enflurane) partially transformed alpha-helix polylysine into beta-sheet. The transformation was reversed by the application of hydrostatic pressure in the range of 100-350 atm. Apparently, the alpha-to-beta transition was induced by anesthetics through partial dehydration of the peptide side-chains (beta-sheet surface is less hydrated than alpha-helix). High pressure reversed this process by re-hydrating the peptide. Because the membrane spanning domains of channel and receptor proteins are predominantly in the alpha-helix conformation, anesthetics may suppress the activity of excitable cells by transforming them into a less than optimal structure for electrogenic ion transport and neurotransmission. Proteins and lipid membranes maintain their structural integrity by interaction with water. That which attenuates the interaction will destabilize the structure. These data suggest that anesthetics alter macromolecular conformations essentially by a solvent effect, thereby destroying the solvation water shell surrounding macromolecules.

Anesthetics↗
PubMed1992

A new canine cruciate ligament formed through distraction histogenesis. Report of a pilot study.

A modified Ilizarov external fixator was used to transfix the stifle joint in 13 dogs. A 1-cm cortical cancellous bone plug was outlined in the intracondylar notch of the femur after excising the anterior (cranial) cruciate ligament (ACL). Hardware attached to the plug allowed controlled distraction of the plug into a cut tibial channel trailing the regenerate ligament. No attempt was made to exactly recreate the normal anatomic course of the ACL. Some bone plugs became dislodged from the femur before distraction began, while others consolidated prematurely. These specimens produced scar only and served as a control group against which the regenerate ligament and normal ACLs were contrasted biomechanically, biochemically, and histologically. The dogs were killed at intervals from four to 21 weeks postoperatively. Load to failure at 21 weeks reached 71% of the mean normal. Histologic examination showed an improved fiber organization of the regenerate compared with the scar group. The regenerate and scar groups showed increased percent water compared with normal, while there was no significant difference in percent collagen and glycosaminoglycan content.

Animals↗
PubMed1991

[Clinical significance of gastrointestinal decontamination under protected environment].

Many infections are caused by the patient's own oro-intestinal microbial flora under a protected environment. Thirty-eight patients with acute leukemia and two patients with blast crisis of chronic myelocytic leukemia were treated under a protected environment with or without prophylactic antibiotics. Antibiotics used for decontamination were vancomycin (V), polymyxin B (P) and nystatin (N). The number of patients in the VPN, PN and the no antibiotic group were 13, 13 and 14, respectively. While the intestinal microbial flora was almost completely eliminated in VPN group, the number of bacteria decreased slightly in PN group. The mean number of pharyngeal and anorectal bacterial species decreased most markedly in the VPN group, but there were no significant differences among the three groups. The number of febrile days was significantly lower in the VPN and PN group than the no antibiotics group with neutrophil counts of less than 100 microliters. The average number of episodes of infection per patient was lowest in VPN group and highest in the no antibiotic group. These data indicate that VPN administration is effective for eliminating intestinal bacterial flora and resultantly protecting endogenous infections.

Adolescent↗
PubMed1990

[Studies of intestinal microbial flora in the post-BMT (bone marrow transplantation) patients under a protected environment].

The changes of microbial burdens of six patients with leukemia (four patients with acute leukemia; two patients with chronic leukemia) were studied before and after bone marrow transplantation (BMT) under protected isolation. Oral nonabsorbable and topical antibodies were administered prophylactically to all patients. Under a protected environment, genus and species number of intestinal microbial flora were not so decreased in all patients who were treated with antibiotics, but no episodes of severe septicemia were detected due to intestinal microbial flora. From many previous reports, the same pathogen was isolated from both blood culture and stool in the patients with septicemia, however, no septicemia developed in our cases in spite of residue of many intestinal bacteria. These data have demonstrated a significant advantage of treatment with protected isolation and intensive antibiotic prophylaxis through oral, topical and intravenous administration for severe infection prevention.

Adolescent↗
PubMed1989

Expression of protein kinase C subspecies in human leukemia-lymphoma cell lines.

Expression of protein kinase C (PKC) subspecies was studied in various human leukemia-lymphoma cell lines. The PKC in most cell lines examined was resolved into two major fractions corresponding to type II (beta-sequence) and type III (alpha-sequence) PKC of the rat brain. The amounts of these two subspecies greatly varied among the cell lines. Type I PKC (gamma-sequence) was expressed in none of the cell lines tested, but PKCs with undefined structures were frequently detected. The differential co-expression of several PKC subspecies is presumably related to the state of cell differentiation.

Animals↗
PubMed1989

[Anesthetic experience in emergency abdominal surgery in a 97-year-old patient complicated with a giant abdominal aneurysm].

We administered general anesthesia for an emergency abdominal surgery due to duodenal ulcer hemorrhage. The patient was in postoperative state after femoral supracondylar fracture, in pre-shock state, of old age (97 y-o), with severe anemia, and hypoproteinemia, and complicated with a giant abdominal aneurysm and mild aortic regurgitation. Before the operation, the patient was transferred to ICU and had intravascular volume replaced (infused with blood 600 ml, crystalloid fluid 2000 ml, colloid fluid 500 ml) and received stomach lavage. Under monitoring of direct arterial pressure, after fully pre-oxygenation, fentanyl 0.1mg was administered slowly, and crush induction was performed by a small dose of thiopental and SCC. After induction of anesthesia systolic blood pressure decreased to 60 mmHg temporarily and it was maintained between 80 and 120 mmHg during the surgery, but tachycardia continued (90-110.min-1). In order to treat oliguria owing to pre-shock state, we administered dopamine and urinastatin continuously. The patient was transferred to ICU postoperatively and close attention was paid. Postoperative pain controlled was well by epidural morphine and bupivacaine. The postoperative course was uneventful without any complications. Twenty three days later, abdominal aortic aneurysm resection was performed uneventfully. In this paper, problems of preanesthetic and anesthetic management of emergency abdominal surgery for an aged patient were discussed.

Aged↗
PubMed1988

The production of anorexigenic substances by intestinal flora.

The role of intestinal flora in the production of anorexigenic substance was investigated. Proteus mirabilis (P. mirabilis) and Escherichia coli (E. coli) were found to produce an anorexigenic substance, while Enterococcus faecalis (E. faecalis, type 1 and 2) and Staphylococcus intermedius (S. intermedius) did not. The anorexigenic substance was purified and was detected as, a single though broad band by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The specific activity of the final form of the purified substance was 120 units/mg carbohydrate. The substance contained no protein residue and appeared to be a lipopolysaccharide. The evidence that intestinal flora produces an anorexigenic substance leads to an interesting assumption that the intestinal flora may be responsible for regulating food intake.

Animals↗
PubMed1988

Microbial ecology and tonsillar infection.

The results of quantitative and qualitative analyses of tonsillar bacterial flora in chronic tonsillitis patients and healthy subjects are reported. Based on these results, the pathogenesis of tonsillar infections is discussed from the standpoint of bacterial ecology.

Adult↗
PubMed1988

Postnatal development of a brain-specific subspecies of protein kinase C in rat.

Protein kinase C in the developing rat brain was investigated by a biochemical assay and by light-microscopic immunocytochemistry. The protein kinase was resolved on hydroxyapatite column chromatography into 3 fractions, designated types I, II, and III. Type I, with structure encoded by a gamma-sequence, was not detected early postnatally, maintained a low level of activity during the first week, which increased gradually, and reached its maximum around postnatal day 28. This type of enzyme was expressed specifically in nervous tissues, and was not found in any other tissues thus far tested. Type II enzyme activity, a mixture of the 2 subspecies encoded by the beta I- and beta II-sequences, was found at birth, increased rapidly, and reached a plateau level between postnatal days 14 and 28. This type was the predominant subspecies of protein kinase C in the brain. Type III, its structure encoded by the alpha-sequence, was also detected at birth, and reached its maximum level on postnatal day 7. Immunocytochemical studies with a monoclonal antibody, which recognized preferentially the type I enzyme, visualized the developmental pattern of type I subspecies in the Purkinje cell, a typical cell having a large quantity of type I protein kinase C.

Aging↗
PubMed1986

The human immune response to reconstituted bovine collagen.

The human immune response to bovine dermal collagen was characterized through histologic, serologic, and immunoblotting methods. Collagen-sensitive patients were identified by hypersensitivity to intradermal exposure to ZYDERM Collagen Implant--a pepsin-solubilized, reconstituted, bovine dermal collagen. Biopsies of test sites in the forearm were obtained from several collagen-sensitive patients. Histologic examination revealed an implant-associated palisading foreign body granuloma. The lesion also contained a mixed cell infiltrate of histiocytes, lymphocytes, and eosinophils. Sera were collected from patients who developed erythema or induration at intradermal test or treatment sites, and were evaluated for antibodies to bovine dermal collagen by an enzyme-linked immunosorbent assay (ELISA). Sera with anti-collagen antibodies were further characterized in this study. The circulating antibodies were reactive with both native and heat-denatured bovine dermal collagen. By using purified alpha 1(I) and alpha 2(I) polypeptides, these sera were found to have antibodies reactive with both alpha-chains. Each alpha-chain was fragmented by using cyanogen bromide (CB). The CB peptides were electrophoretically separated, and these sera were evaluated for antibodies to the major fragments by using an immunoblotting technique. Of the sera evaluated by this method, 89% (23/26) had antibodies to alpha 1-CB6; 77% (20/26) had antibodies to alpha 2-CB4; and 65% (17/26) had antibodies reactive with both CB fragments. In addition, most sera (77%) contained antibodies reactive with two or more (up to five) of the major CB peptides. The least antigenic fragment was alpha 2-CB3,5 (8%). In addition, these sera had antibody activity against both native and heat-denaturated bovine types III and II collagens. Little or no interspecies (rat or guinea pig) cross-reactivity (types I and II) was detected. Furthermore, these sera did not have antibodies against human types I, II, and III collagens.

Animals↗
PubMed1986

The preparation and physicochemical characterization of an injectable form of reconstituted, glutaraldehyde cross-linked, bovine corium collagen.

Pepsin-solubilized bovine corium collagen was purified, reconstituted, and treated with various levels of glutaraldehyde. Treatment of suspensions of fibrillar collagen with low concentrations of glutaraldehyde appeared to have little effect on the gross morphology of fibrils, as judged by electron microscopy, but did have a significant impact on their physicochemical stability. Fibrillar collagen treated with glutaraldehyde at a concentration equal to or greater than 0.0075% demonstrated significant decreases in neutral solubility at elevated temperatures as compared to noncross-linked controls. Differential scanning calorimetry provided a convenient and quantitative means to correlate increases in melting temperature with increases in glutaraldehyde treatment concentration. Fibrillar collagen cross-linked with glutaraldehyde concentrations as low as 0.0075% demonstrated a significantly greater resistance to proteolytic degradation than did noncross-linked fibrillar collagen samples. The residual, extractable aldehyde content of such preparations was between 1 and 3 ppm. Rheological measurements on such cross-linked suspensions demonstrated that they were non-Newtonian, shear-thinning fluids, and that they were two- to threefold more viscous than corresponding preparations of noncross-linked collagen.

Amino Acids↗
PubMed1986

An examination of the biologic response to injectable, glutaraldehyde cross-linked collagen implants.

The biologic response to injectable, glutaraldehyde cross-linked, fibrillar collagen implants in the rat subcutaneous model was shown to be a function of the concentration of glutaraldehyde used for cross-linking. The collagen was prepared from bovine hide by pepsin solubilization and reconstituted as a fibrillar suspension of 35 mg collagen/mL. Fibrillar collagen implants cross-linked with glutaraldehyde concentrations equal to or less than 0.01% exhibited a response characterized by fibroblast invasion, neovascularization and little, if any, evidence of inflammation. Implants cross-linked with 0.1 and 1.0% glutaraldehyde elicited a foreign body/giant cell reaction and varying degrees of implant erosion. The interaction of human skin fibroblasts with 0.01% glutaraldehyde cross-linked collagen in vitro was found to be dependent on the culture conditions utilized to evaluate the interaction. When the ratio of cell culture media to collagen was 20:1, cell invasion of the cross-linked preparations was observed, whereas, when this ratio was reduced to 1:1, such interactions could not be detected. Noncross-linked preparations were colonized by cells regardless of the experimental conditions used. Studies of implants in both the rat and guinea pig subcutaneous models indicated that glutaraldehyde cross-linking concentrations as low as 0.0075% provided enhanced wet weight recovery (wet weight persistence) and resistance to biologic degradation (collagen persistence) as compared to noncross-linked fibrillar collagen preparations. These cross-linked implants also exhibited a greater degree of fibroblast infiltration and vascularization. Between 30 and 60 days, some degree of calcification developed in both collagen formulations implanted in rats and guinea pigs; however, the reaction occurred with greater frequency and intensity in cross-linked preparations in guinea pigs. Calcification in the guinea pig was followed by the appearance of focal areas of ossification.

Animals↗