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Biomedical subjects

K Miyahara

Publications and source records attributed to K Miyahara.

At least 127 records · Page 7Linked to original sources
PubMed1994

Phosphocholine-bonded galactosylceramides having a tri-unsaturated long-chain base from the clam worm, Marphysa sanguinea.

Seven glycosphingolipids were obtained in the pure state from the clam worm, Marphysa sanguinea, by preparative HPLC with a reversed-phase column in a recycling mode. Their structures were elucidated based on detailed analyses of 1H- and 13C-NMR spectra of the intact compounds. The position and the geometry of double bonds in the long-chain base (LCB) were determined by the two-dimensional NMR (COSY, NOESY, and HMBC) analyses. All compounds are phosphocholine-bonded monogalactosylceramides and two of them have tri-unsaturated long-chain bases.

Animals↗
PubMed1994

Resin glycosides. XXI. Tuguajalapins I-X, the resin glycosides having long-chain fatty acid groups from the root of Merremia hungaiensis.

Ten resin glycosides (jalapins) named tuguajalapins I-X were isolated from the root of Merremia hungaiensis. Their structures have been determined on the bases of chemical and spectral data. Unlike the jalapins so far reported, all of their acyl groups consist of two or three long-chain fatty acids, that is, palmitic, stearic and/or arachidic acids.

Carbohydrate Sequence↗
PubMed1994

Effect of atrial fibrillation on the fibrino-coagulation system--study in patients with paroxysmal atrial fibrillation.

To clarify the effect of atrial fibrillation (AF) on the fibrino-coagulation system, fibrino-coagulation parameters in the paroxysmal period of AF were determined in 13 patients with paroxysmal atrial fibrillation (PAF) and compared with those in the non-paroxysmal period of AF, and with those in normal subjects. Estimated titers of hemoglobin and hematocrit in the paroxysmal period of AF were significantly higher than those in the non-paroxysmal period and also higher than those in normal subjects. The activated partial thromboplastin time in the paroxysmal period was also longer than that in the non-paroxysmal period of AF or in normal subjects. However, other estimated parameters, such as prothrombin time, fibrinogen, thrombin-antithrombin III, beta-thromboglobulin, platelet factor 4, D-dimer and plasmin inhibitor complex, did not show any significant deviation. These results conflict with those of previous reports which indicated that the fibrino-coagulation system was enhanced in cases of chronic AF. Our results suggest that there is no significant activation of the fibrino-coagulation system, except for obvious hemoconcentration, within the first few hours after the onset of PAF. Thus, in terms of the properties of blood coagulation, thromboembolism is preventable if antiarrhythmic therapy is administered within several hours after the onset of PAF.

Aged↗
PubMed1994

A case of myocardial infarction showing extensive precordial ST elevation induced by second diagonal branch occlusion.

We observed a case of acute myocardial infarction induced by second diagonal branch occlusion. Electrocardiogram (ECG) on admission showed ST elevation in leads I, aVL and V2-6. Since emergency coronary angiography disclosed complete occlusion of the second diagonal branch, intra-coronary thrombolysis (ICT) was performed, superselectively. Transient coronary reperfusion was obtained, however, reocclusion occurred after several minutes. Rescue percutaneous transluminal coronary angioplasty (PTCA) was then performed immediately and blood flow was improved to TIMI grade 2. During these processes, the ST-segment on the ECG changed in leads I, aVL and V2-6 always corresponding to the blood flow of the second diagonal branch. We have not seen a report hitherto in which occlusion of only the second diagonal branch could be a cause of extensive anterior infarction-like ECG changes. Although the mechanism of ECG changes in this patient cannot be clearly explained by conventional concepts, we report this case because it is considered to be very rare.

Aged↗
PubMed1994

Infective endocarditis caused by an indigenous bacterium (Gemella morbillorum).

A case of infective endocarditis (IE) caused by a rare pathogen, Gemella morbillorum, is presented. Because of persistent low-grade fever after dental treatment, the patient was given oral antibiotics. Whereas he was diagnosed as having aortic regurgitation by a cardiologist, and IE was not suggested unfortunately. After long-term chemotherapy over five months, he was aware of nocturnal dyspnea and Gemella morbillorum was detected by blood culture. Then, he was treated with intravenous administration of Penicillin-G, and underwent surgical operation for valve replacement. No cases of IE due to this organism have been reported in Japan.

Endocarditis, Bacterial↗
PubMed1994

[Operative results of total replacement of the ascending aorta and aortic valve--characteristic difference between Bentall's and Cabrol's procedures].

From May 1979 to November 1991, 26 patients underwent total replacement of the ascending aorta and aortic valve. We employed 15 Bentall's procedure (group B) and 11 Cabrol's procedure (group C). There were no significant difference in age and etiology between the two groups. Inclusion technique was used in all patients. Compared group B with group C, both the operation time and the aortic cross-clamp time were significantly shorter in group C than in group B. (p < 0.05, p < 0.01 respectively). There were no operative death in group B and one in group C. There were two death in group B in later postoperative period. One was due to the anastomotic leakage at the distal site with infection, and the other was cardiac death caused by the infectious fistula between wrapping cavity and RA. The postoperative actuarial survival rate for group B at 12.8 years was 86.7% and that for group C at 5.1 years was 90.9%. The late complications such as coronary-graft anastmotic leakage or pseudoaneurysm, hematoma between the wrap and the graft and anastomotic leakage at the distal site were recognized more in group B. In group C no pseudoaneurysm were noted, but hematoma was noted in two patients. The rate of complications in late phase was significantly lower in group B (p < 0.05). Although as a procedure of total replacement of the ascending aorta and aortic valve both Bentall's and Cabrol's procedure represent satisfactory operative results, Cabrol's procedure has some advantages and fewer postoperative complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Isolation and characterization of a novel type of glycosphingolipid from Neanthes diversicolor.

Five glycosphingolipids were obtained in the pure state from the marine annelid, Neanthes diversicolor. Final isolation of the individual compound was achieved by means of preparative HPLC with a reversed phase column in a recycling mode. They were assigned the structures, 1-O-beta-D-(6-O-[2'-(trimethylammonio)- ethylphosphoryl])galactopyranosyl, -N-hexadecanoyl-(4E,8E)-sphingadiene (1), -N-hexadecanoyl-(4E)-sphingenine (2), -N-heptadecanoyl-(4E)-sphingenine (3), -N-octadecanoyl-(4E)-sphingenine (4) and -N-hexadecanoyl-sphinganine (5). It is noted that they are the monogalactosyl ceramides carrying the phosphocholine group in the galactose moiety, and that one of them contains an odd numbered fatty acid residue.

Animals↗
PubMed1993

Common sequence elements are important for transcription and replication of the extrachromosomal rRNA-encoding genes of Tetrahymena.

Three types of conserved sequence elements have previously been identified in the generally non-conserved, 5' non-transcribed spacer region of the rRNA-encoding gene (rDNA) of Tetrahymena species. In vivo and in vitro experiments have identified the start point (tsp) for rDNA transcription. Comparative sequence analysis suggested that the type-I sequence element was likely to function as the promoter for rDNA transcription. We have used in vitro transcription assays to demonstrate that sequences in the 3' half of the type-I repeat located proximal to the tsp are essential for the accurate initiation of rRNA synthesis. These sequences define the 5' boundary of the core or minimal promoter element and include the sequences which function in rDNA replication and maintenance in the homologous regions in two upstream type-I sequence elements. These sequences may bind factors important for both the transcription and replication of rDNA.

Animals↗
PubMed1993

Congenitally defective aldosterone biosynthesis in humans: inactivation of the P-450C18 gene (CYP11B2) due to nucleotide deletion in CMO I deficient patients.

CYP11B2, the gene coding for steroid 18-hydroxylase (P-450C18), has been recently shown to be the same gene as that for corticosterone methyl oxidase type I and type II (CMO I & II) which were previously postulated to catalyze the final two steps in the biosynthesis of aldosterone in humans. Molecular genetic analysis of CYP11B2 of three patients affected with CMO I deficiency has revealed that deletion of 5 nucleotides occurs exclusively in exon 1, resulting in a frameshift to form a stop codon in the same exon. Thus, P-450C18 is not produced at all due to the mutation, causing a complete lack of aldosterone biosynthesis in the patients. Restriction fragment length polymorphism analysis has demonstrated that the patients are homozygous and the unaffected parent is heterozygous as for the mutation, indicating that CMO I deficiency is inherited in an autosomal recessive manner. These results provide the molecular genetic basis for the characteristic biochemical phenotype of CMO I deficient patients.

Aldosterone↗
PubMed1993

Poly(ADP-ribose) polymerase stimulates DNA polymerase alpha by physical association.

The direct effect of the eukaryotic nuclear DNA-binding protein poly(ADP-ribose) polymerase on the activity of DNA polymerase alpha was investigated. Homogenously purified poly(ADP-ribose) polymerase (5 to 10 micrograms/ml) stimulated the activity of immunoaffinity-purified calf or human DNA polymerase alpha by about 6 to 60-fold in a dose-dependent manner. It had no effect on the activities of DNA polymerase beta, DNA polymerase gamma, and primase, indicating that its effect is specific for DNA polymerase alpha. Apparently, poly(ADP-ribosyl)ation of DNA polymerase alpha was not necessary for the stimulation. The stimulatory activity is due to poly(ADP-ribose) polymerase itself since it was immunoprecipitated with a monoclonal antibody directed against poly(ADP-ribose) polymerase. Kinetic analysis showed that, in the presence of poly(ADP-ribose) polymerase, the saturation curve for DNA template primer became sigmoidal; at very low concentrations of DNA, it rather inhibited the reaction in competition with template DNA, while, at higher DNA doses, it greatly stimulated the reaction by increasing the Vmax of the reaction. By the automodification of poly(ADP-ribose) polymerase, however, both the inhibition at low DNA concentration and the stimulation at high DNA doses were largely lost. Furthermore, stimulation by poly(ADP-ribose) polymerase could not be attributed to its DNA-binding function alone since its fragment, containing only the DNA-binding domain, could not exert full stimulatory effect on DNA polymerase, as of the intact enzyme. Poly(ADP-ribose) polymerase is co-immunoprecipitated with DNA polymerase alpha, using anti-DNA polymerase alpha antibody, clearly showing that poly(ADP-ribose) polymerase may be physically associated with DNA polymerase alpha. In a crude extract of calf thymus, a part of poly(ADP-ribose) polymerase activity existed in a 400-kDa, as well as, a larger 700-kDa complex containing DNA polymerase alpha, suggesting the existence in vivo of a complex of these two enzymes.

Animals↗
PubMed1993

A nonsense mutation (TGG [Trp116]-->TAG [Stop]) in CYP11B1 causes steroid 11 beta-hydroxylase deficiency.

Steroid 11 beta-hydroxylase deficiency (11 beta OHD), an autosomal recessive hereditary disease, accounts for 5-8% of cases of congenital adrenal hyperplasia. In this study, we carried out a molecular genetic analysis of CYP11B1 encoding steroid 11 beta-hydroxylase (P450c11) from a Japanese patient affected with this disease. Nucleotide sequence analysis of polymerase chain reaction-amplified products of the patient's genome revealed the occurrence of a stop codon in exon 2 due to a point mutation, TGG-->TAG (Trp116-->Stop). To further analyze the role of CYP11B2 encoding steroid 18-hydroxylase (P450c18) in the 11 beta OHD patient, CYP11B2 of the patient was also amplified and sequenced. In contrast to CYP11B1, there was no mutation in CYP11B2. Restriction fragment length polymorphism analysis indicated that the 11 beta OHD patient is homozygous and his unaffected parents are heterozygous for the mutation. When a cDNA corresponding to CYP11B1 of the 11 beta OHD patient was transfected into COS-7 cells, steroid 11 beta-hydroxylase activity was not detectable in mitochondria of the cells. These results demonstrate that intact P450c11 was not produced at all due to the nonsense mutation in CYP11B1 of the patient without any mutation in CYP11B2.

Adrenal Hyperplasia, Congenital↗
PubMed1993

Isolation and characterization of seven lyso platelet-activating factors and two lyso phosphatidylcholines from the crude drug "suitetsu" (the leech, Hirudo nipponica).

Nine lyso glycerophospholipids were isolated in the pure state from the crude drug "Suitetsu", which is the dried body of the leech, Hirudo nipponica (Hirudidae). They were identified as 1-O-hexadecyl-(1), 1-O-octadecyl-(2), 1-O-tetradecyl-(3), 1-O-9-cis-hexadecenyl-(4), 1-O-hexadecanoyl-(5), 1-O-pentadecyl-(6), 1-O-15-methylhexadecyl-(7), 1-O-octadecanoyl-(8) and 1-O-heptadecyl-sn-glycero-3-phosphocholine (9). Two of them (5 and 8) are lysophosphatidylcholines and the other seven are lyso platelet-activating factors. One of them has an alkenyl carbon chain.

Animals↗
PubMed1993

Resin glycosides. XIX. Woodrosins I and II, ether-insoluble resin glycosides from the stems of Ipomoea tuberosa.

Two new ether-insoluble resin glycosides named woodrosins I and II were isolated from the stems of Ipomoea tuberosa L., and their structures were determined on the basis of chemical and spectral data. Contrary to anticipation, they had an intramolecular cyclic ester structure similar to that of ether-soluble resin glycosides (Mayer's jalapin) hitherto isolated. It is proposed to use the terms, "jalapin" and "convolvulin," not according to the solubility in ether (Mayer's classification), but according to the structure, i.e., intramolecular esters and others, respectively.

Carbohydrate Sequence↗
PubMed1993

Relationships between left ventricular mass, left ventricular work and coronary artery size in aortic regurgitation--possible mechanism of myocardial ischemia.

To investigate the relationships between coronary artery size, left ventricular (LV) mass, and LV stroke work in aortic regurgitation (AR), these values were measured in 19 patients with severe AR. Twenty normal subjects and 15 patients with mitral regurgitation (MR) were used as control groups. The coronary area index, i.e., the coronary cross-sectional area divided by body surface area (BSA), was larger in the AR group than in the control groups in all measured sites except for the peripheral left anterior descending coronary artery (LAD) and right coronary artery (RCA). However, the coronary area index divided by the LV mass was significantly smaller in AR and MR patients than in normal subjects. Furthermore, the coronary area index divided by LV stroke work was smaller in AR patients than in MR patients and normal subjects. These results suggest that the coronary blood flow associated with the increased LV mass and stroke work caused by regurgitation was insufficient in patients with severe AR, especially in the area of the LAD. Therefore, the occurrence of myocardial ischemia in patients with severe AR may involve inadequate enlargement of the coronary artery which perfuses the LV, in addition to factors such as decreased coronary perfusion pressure, increased coronary artery resistance and decreased coronary flow reserve.

Adult↗
PubMed1993

Immunological aspects in patients with acute myocardial infarction.

In order to elucidate the immunological aspects of acute myocardial infarction (AMI), we studied lymphocyte subpopulations, immunoglobulin levels, and natural killer (NK) cell activity in 21 patients serially after admission within 24 h of AMI onset. The percent T cells, T cell count, and percent CD4-positive cells were significantly decreased on the 1st hospital day, compared to days 7 and 28. The CD4/CD8 ratio on the 1st day was also significantly lower than on day 7, and was significantly lower than that of normal subjects. Natural killer (NK) cell activity and serum immunoglobulin G (IgG) levels showed substantial decreases each test day, compared with those in normal subjects. However, there were no significant serial changes in the percent B cells, the B cell count, or in the serum IgG, IgA, or IgM levels. Thus, not only T cell function, but also immunoglobulin levels and NK cell activity were depressed in the acute stage of myocardial infarction. Therefore, active measures should be taken to prevent infection in the acute stage of myocardial infarction in which invasive procedures such as insertion of indwelling catheters are often necessary.

Aged↗
PubMed1993

Left ventricular wall thickness in normal mongrel dogs.

To clarify the normal value of ventricular wall thickness we directly measured the ventricular wall thickness of 50 normal mongrel dogs of one year old. Because of a wide range in body weight from 6.0 to 16.0 kg of these 50 dogs, we selected 34 dogs weighing 8 to 12 kg to calculate the mean ventricular wall thickness as normal value of one year old. The results obtained were as follows; (1) The mean and standard deviation of the left ventricular wall thickness was 7.1 +/- 1.2 mm at anterior, 6.3 +/- 1.6 mm at posterior, 7.1 +/- 1.3 mm at lateral, 10.3 +/- 1.8 mm at the interventricular septum, and that of the right ventricular wall thickness was 3.4 +/- 1.0 mm. (2) Although any site of the ventricular wall thickness correlated significantly to heart weight, only the anterior left ventricular wall and interventricular septum barely correlated to body weight. (3) There was no significant correlation between arterial blood pressure and the ventricular wall thickness. Further study should be necessary to clarify influences of aging on the ventricular thickness and to determine the criteria of ventricular hypertrophy.

Alanine Transaminase↗
PubMed1993

[Pressure distribution on the sole in normal adult men during walking using the ANIMA-G2800 for recording].

Pressure distribution on the sole during walking has been considered a useful indicator in the treatment of various foot disorders. In this study, the present worker recorded pedobarograms of 31 normal adult males in order to clarify patterns of pressure distribution on the sole during walking, and investigate influential factors behind these patterns. Pedobarograms were used to depict pressure distribution on the sole, and the ANIMA-G2800 was utilized for recording. At the pedobaragram analyses of the distribution of maximum pressure areas during walking, the author studied relationships between pressure distribution patterns and changes in the medial arch of the foot, step length, step width, foot angle, and angle of the subtalar joint. The distribution of the pressure areas, 0.2, 0.5, and 0.8 kg/cm2 in all 31 subjects was similar. The pedobarograms showed 3 distribution patterns of the pressure levels in the forefoot, and each subject had a combination of these patterns. Type A had the maximum pressure area on the first metatarsal head. Type B had the maximum pressure areas on the second and third metatarsal heads. The maximum pressure areas for Type C were either on all 3 metatarsal heads or on both the first and third metatarsal heads. Type A had such characteristic features as: smaller changes in the length of the medial arch and in the angle of inversion, smaller foot angle, and larger step width than those of Type B. The present work has concluded that these variations in pressure distribution patterns on the sole appear to be produced through the body's normal adjustment mechanism to maintain a smooth and effective walking step.

Adult↗