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Biomedical subjects

H Nishida

Publications and source records attributed to H Nishida.

At least 379 records · Page 21Linked to original sources
PubMed1991

Purpactins, new inhibitors of acyl-CoA:cholesterol acyltransferase produced by Penicillium purpurogenum. II. Structure elucidation of purpactins A, B and C.

The structure of purpactins, novel acyl-CoA:cholesterol acyltransferase (ACAT) inhibitors, was determined by spectroscopic analyses. Purpactin A was deduced to be 3-1'-acetoxy-11-hydroxy-4-methoxy-9-methyl-3'-methylbutyl-5H, 7H-dibenzo[b,g]-1,5-dioxocin-5-one, purpactin B was 5-1''-acetoxy-6'-hydroxymethyl-4-methoxy-4'-methyl-3''-methylbutyl-spiro [benzofuran-2,1'-cyclohexa-3',5'-diene]-2',3(2H)-dione and purpactin C was 5-1''-acetoxy-6'-formyl-4-methoxy-4'-methyl-3''-methylbutyl-spiro [benzofuran-2,1'-cyclohexa-3',5'-diene]-2',3(2H)-dione. Purpactin A was attributed to 1'-O-acetylpenicillide.

Benzofurans↗
PubMed1991

Purpactins, new inhibitors of acyl-CoA:cholesterol acyltransferase produced by Penicillium purpurogenum. III. Chemical modification of purpactin A.

Acylated derivatives of the C-1' and/or C-11 hydroxy group(s) of penicillide were synthesized and their inhibitory activity against acyl-CoA:cholesterol acyltransferase (ACAT) was studied. Introduction of long acyl group into either or both hydroxy residue(s) decreased the inhibitory activity. A small acyl moiety such as acetyl or n-butyryl at the C-1' hydroxy group is responsible for potent inhibitory activity against ACAT. The 1'-O-acetyl-11-O-tetrahydropyranyl derivative (11-O-2''-tetrahydropyranylpurpactin A) showed high selectivity (cytotoxic dose vs. effective dose) in a cell assay using J774 macrophages.

Animals↗
PubMed1991

Clinical alternative bypass conduits and methods for surgical coronary revascularization.

Poor quality or inadequate length of venous and mammary conduits, or both, a severely calcified or atherosclerotic aorta, or diffuse coronary atherosclerosis are situations cardiovascular surgeons will be facing with increasing frequency. These conditions are more common to the increasing number of patients requiring reoperation for advancing disease and to the growing number of older patients requiring operation. Decisions will be made preoperatively or intraoperatively about the technique to be used. Extensive use of the internal mammary arterial graft, such as bilateral internal mammary artery bypass, sequential use of the mammary artery and use of a free internal mammary artery graft, are excellent choices. These methods can overcome some of the difficult situations of the severely calcified atherosclerotic aorta or the absence of adequate venous conduits. Coronary arterial bypass using the inverted internal mammary conduit has too low a flow to be considered. Composite conduits will help gain the length needed to solve both the inadequate length problem and the severely diseased aorta. Little clinical experience is reported to date. These methods should only be used when nothing else is available. The innominate to coronary arterial bypass and the left subclavian to coronary arterial bypass can help solve the problem of the severely atherosclerotic aorta. The coronary to coronary arterial bypass has been used to solve both the severely diseased aorta and the short conduit situation. These methods, while ingenious, are supported only by occasional isolated clinical experiences. A large number of researchers have done extensive work on the selective retrograde coronary venous bypass grafting, but the last published article of any clinical importance dates back to 1979 and this suggests that other alternatives may be better. This technique should be used as a last resort. The surgical arteriovenous fistula has been clinically applied during the coronary artery bypass procedure. The nonconduit revascularization technique of coronary artery endarterectomy is needed in the armamentarium of the surgeon. This technique is not ideal but presently has better results than intraoperative transluminal coronary angioplasty and far better results than laser angioplasty. These methods may be useful to solve the diffuse coronary arterial problem, but sequential grafting techniques should be considered first.

Angioplasty, Balloon, Coronary↗
PubMed1991

[Successful surgical correction of endocardial cushion defect in a 63-year-old female patient].

We have experienced a surgical correction of a 63-year-old female patient with ECD, who had suffered from severe congestive heart failure. Massive left to right shunt and severe mitral and tricuspid regurgitation were noted. The correction consisted of mitral valve replacement, patch closure of the ostium primum defect and annuloplasty of tricuspid valve. Postoperative course was uneventful. Surgical correction should be recommended even in old patient.

Endocardial Cushion Defects↗
PubMed1991

Discriminate use of electrocautery on the median sternotomy incision. A 0.16% wound infection rate.

Between June 1978 and June 1989, superficial or deep mediastinitis (or both) developed in only five (0.16%) of 3118 consecutive patients. All patients studied underwent cardiac procedures through a median sternotomy and survived more than 7 postoperative days. The surgical team disciplined itself to divide presternal soft tissues with a scalpel and used electrocautery for pinpoint hemostasis only. This 0.16% infection rate was statistically significantly lower than those in 28 previously published studies (Pearson's chi 2 test, p less than 0.05). Twenty-four predisposing factors were evaluated by Fisher's exact test. Among these only an operating time longer than 3 hours is related to sternotomy infections (p = 0.0208), and this effect was not a strong one. Statistical evidence strongly suggests that discriminate use of electrocautery is a major reason for the lowest median sternotomy infection rate reported to date.

Adult↗
PubMed1990

Coronary artery bypass in a 15-year-old girl with pseudoxanthoma elasticum.

A 15-year-old girl with pseudoxanthoma elasticum and associated severe coronary artery disease underwent double coronary artery bypass using left internal mammary artery and saphenous vein. Preoperatively the patient had life-threatening syncope and positive treadmill test results. The postoperative course was uneventful, and the patient has been doing well for 3 years. Pseudoxanthoma elasticum is a rare disease that can cause premature coronary arterial obstructive disease in children and adolescents.

Adolescent↗
PubMed1990

Determinative mechanisms in secondary muscle lineages of ascidian embryos: development of muscle-specific features in isolated muscle progenitor cells.

Muscle cells of the ascidian larva originate from three different lines of progenitor cells, the B-line, A-line and b-line. Experiments with 8-cell embryos have indicated that isolated blastomeres of the B-line (primary) muscle lineage show autonomous development of a muscle-specific enzyme, whereas blastomeres of the A-line and b-line (secondary) muscle lineage rarely develop the enzyme in isolation. In order to study the mechanisms by which different lines of progenitors are determined to give rise to muscle, blastomeres were isolated from embryos of Halocynthia roretzi at the later cleavage stages when conspicuous restriction of the developmental fate of blastomeres had already occurred. Partial embryos derived from B-line muscle-lineage cells of the 64-cell embryo (B7.4, B7.5 and B7.8) showed autonomous expression of specific features of muscle cells (acetylcholinesterase, filamentous actin and muscle-specific antigen). In contrast, b-line muscle-lineage cells, even those isolated from the 110-cell embryo (b8.17 and b8.19), did not express any muscle-specific features, even though their developmental fate was mainly restricted to generation of muscle. Isolated A-line cells from the 64-cell embryos (A7.8) did not show any features of muscle differentiation, whereas some isolated A-line cells from the 110-cell embryos (A8.16) developed all three above-mentioned features of muscle cells. This transition was shown to occur during the eighth cell cycle. These results suggest that the mechanism involved in the process of determination of the secondary-lineage muscle cells differs from that of the primary-lineage muscle cells. Interaction with cells of other lineages may be required for the determination of secondary precursors to muscle cells. The presumptive b-line and A-line muscle cells that failed to express muscle-specific features in isolation did not develop into epidermal cells. Thus, although interactions between cells may be required for muscle determination in secondary lineages, the process may represent a permissive type of induction and may differ from the processes of induction of mesoderm in amphibian embryos.

Acetylcholinesterase↗
PubMed1990

The immunotoxicity of triphenyltin chloride in mice.

The immunotoxicity of triphenyltin chloride (TPTC) in mice was investigated. 1) When TPTC was injected intraperitoneally (i.p.) into mice at doses between 1 and 10 mg/kg for 14 d, a reduction in the weights of thymus and spleen was noticed, however, the body weight was not changed significantly. 2) The production of hemolytic plaque forming cells in the spleen of mice immunized with sheep red blood cells (SRBC) was inhibited by the administration of 10 mg/kg of TPTC. 3) The i.p. injection of TPTC at a dose of 10 mg/kg for 5 d after the primary immunization of mice with dinitrophenylated ascaris antigen resulted in suppression of immunoglobulin E antibody formation in primary immune response, but did not affect the secondary immune response. 4) The production of antibody against polyvinylpyrrolidone (T cell independent antigen) was not affected by the administration of TPTC. 5) The production of effector T cells which are able to cause SRBC- or tuberculin-induced footpad reaction in mice and the induction of cytotoxic T cell in local graft versus host reaction in mice were also inhibited by TPTC. These results indicate that TPTC inhibits both the T cell dependent humoral and cellular immune responses in mice.

Animals↗
PubMed1990

The structures of atpenins A4, A5 and B, new antifungal antibiotics produced by Penicillium sp.

The structures of atpenins A4, A5 and B, new antifungal antibiotics produced by Penicillium sp., have been deduced to be I, II and III, respectively, on the basis of spectroscopic and 1H and 13C NMR spectral data. The molecular structure of atpenin A4 with absolute configurations was finally confirmed to be 2'S,4'S,5'S-5,6-dimethoxy-4-hydroxy-5'-chloro-2',4'- dimethyl-1'-oxoheptyl-2-hydroxypyridine (I') by the single crystal X-ray crystallographic analysis. The absolute configurations of atpenins A5 and B were also expected to be 2'S,4'S,5'R-II (II') and 2'S,4'R-III (III'), respectively.

Antifungal Agents↗
PubMed1990

CP-84,657, a potent polyether anticoccidial related to portmicin and produced by Actinomadura sp.

A new polyether antibiotic CP-84,657 (C45H78O14) was isolated by solvent extraction from the fermentation broth of Actinomadura sp. (ATCC 53708). Following purification by column chromatography and crystallization, the structure of CP-84,657 was elucidated by spectroscopic (NMR and MS) methods. The absolute stereochemistry was determined by a single crystal X-ray analysis of the corresponding rubidium salt. CP-84,657 is among the most potent anticoccidal agents known, effectively controlling the Eimeria species that are the major causative agents of chicken coccidiosis at doses of 5 mg/kg or less in feed. It is also active in vitro against certain Gram-positive bacteria, as well as the spirochete, Treponema hyodysenteriae.

Actinomycetales↗
PubMed1990

Complete amino acid sequence of luffin-a, a ribosome-inactivating protein from the seeds of sponge gourd (Luffa cylindrica).

The complete amino acid sequence of luffin-a has been determined. Twenty-two peptides were isolated from the tryptic digest of luffin-a and sequenced employing the DABITC/PITC double coupling method. Overlaping of these peptides was achieved by analyzing the chymotryptic peptides or CNBr-fragments of luffin-a and their S. aureus V8 protease peptides. Luffin-a consists of 248 amino acid residues and its relative molecular mass is calculated to be 27,021 Da, excluding the attached sugar chains reasoned to be present at each Asn residue of positions 28, 33, 77, 84, 206, and 227. A comparison with the sequence of ricin A-chain showed 33% sequence identity indicating that these proteins are homologous.

Amino Acid Sequence↗
PubMed1990

Surfactant replacement therapy with a single postventilatory dose of a reconstituted bovine surfactant in preterm neonates with respiratory distress syndrome: final analysis of a multicenter, double-blind, randomized trial and comparison with similar trials. The Surfactant-TA Study Group.

The effects of a single dose of surfactant TA were assessed in premature neonates (birth weight 750 to 1749 g) with respiratory distress syndrome (RDS) in a multicenter, double-blind, randomized clinical trial. Only neonates with surfactant deficiency and without ultrasonographic evidence of intracranial hemorrhage greater than or equal to grade II were enrolled. Fifty-four patients received surfactant (100 mg of phospholipid per kilogram of body weight) and 46 patients received an air placebo within 8 hours of life. Treatment with this surfactant resulted in a significant reduction in the severity of RDS with a concomitant increase in the proportion of neonates with mild disease. The frequency of pulmonary interstitial emphysema and of pneumothorax was significantly lower in treated neonates compared with control neonates (2% vs 26%, P = .0008, and 7% vs 39%, P = .0004, respectively). The frequency of intracranial hemorrhage was significantly lower in the surfactant group compared with the control group (20% vs 54%, P = .0008) and was also reduced for the smallest neonates in the surfactant group (13% vs 73%, P = .00008). When categorized according to severity of intracranial hemorrhage and severity of bronchopulmonary dysplasia, the surfactant group was at a significant advantage (adjusted Cochran-Mantel-Haenszel X2 = 10.72, P less than .001 and X2 = 4.43, P = .036, respectively). The proportion of neonates surviving without intracranial hemorrhage and/or bronchopulmonary dysplasia was 63% in the surfactant group vs 26% in the control group (P = .0004); as for the smallest neonates, it was 58% in the surfactant group vs 4% in the control group (P = .0002). There were no differences between the groups with respect to the frequency of patent ductus arteriosus (46% vs 37%), pulmonary hemorrhage (6% vs 7%), necrotizing enterocolitis (0% vs 2%), sepsis (4% vs 2%), retinopathy of prematurity (13% vs 22%), or death (15% vs 22%). It is concluded that treatment with the single-dose surfactant regimen used in this study reduces the severity of respiratory distress during the 48 hours after treatment and decreases the major pulmonary morbidity and intracranial hemorrhage in premature neonates with RDS. Further studies are needed to determine whether (1) treatment at birth or as soon as after RDS is diagnosed and (2) the use of multiple dose of this surfactant would result in any additional benefits.

Bronchopulmonary Dysplasia↗
PubMed1990

Postoperative mediastinitis: a comparison of two electrocautery techniques on presternal soft tissues.

Postoperative mediastinitis remains a serious surgical problem, complicating 0.4% to 5% of all cases. In an experiment designed to address this problem, 36 mongrel dogs underwent a median sternotomy incision. In group I (n = 18) all layers to the sternum were opened by a scalpel, and electrocautery was used only for pinpoint hemostasis. In group II (n = 18) the skin was opened by a scalpel and the remaining layers to the sternum were opened by electrocautery. Total kilojoules of electrical energy delivered to the tissues was 9.4 +/- 5.7 for group I and 44.1 +/- 7.0 for group II (p less than 0.001). Each group was randomly divided into three subgroups (n = 6): Ia and IIa were noninoculated controls; Ib and IIb were inoculated just before skin closure; Ic and IIc were inoculated and given one preoperative dose of cefonicid. The inoculum contained Staphylococcus intermedius in a 0.5 ml suspension of 10(8) organisms. Each animal was observed and the wounds were scored daily until death or until all survivors were put to death on the eighth postoperative day. Pleural fluid was cultured at autopsy. Ten dogs died of mediastinitis (four in IIa and six in IIb), but none from group I (p less than 0.01). Positive cultures from pleural fluid in matching subgroups (n = 6) occurred as follows: one in Ia and five in IIa (p less than 0.05); one in Ib and six in IIb (p less than 0.01); zero in Ic and two in IIc. We conclude that pinpoint hemostasis on the soft tissues of the sternotomy incision significantly reduces the severity and frequency of penetrating mediastinitis.

Animals↗