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Biomedical subjects

M Kuwabara

Publications and source records attributed to M Kuwabara.

At least 181 records · Page 10Linked to original sources
PubMed1990

[Renal function after aortic reconstruction for aortic dissection: special reference to the renal blood flow from false lumen].

Relationships between preoperative renal blood flow and postoperative renal dysfunction after aortic reconstruction for aortic dissection of DeBakey I and IIIb type were discussed. The incidence of renal dysfunction after surgery was not so high and renal failure was transient. Renal dysfunction occurred in the cases with true lumen oppressed by false lumen at chronic stage. Sometimes, abnormal findings were showed in CT scanning and/or renogram even in serum creatinine or BUN value was normal. In conclusion, our data showed justification of anastomosis of distal artificial graft to true lumen in acute stage. But in chronic stage, it is very important in point of selection of operative method to recognize how renal blood flow was preserved and to know the location and size of reentry before surgery.

Adolescent↗
PubMed1990

[Case report of the superior approach for correction of the supracardiac type of total anomalous pulmonary venous drainage (TAPVD) in the neonatal period].

An eleven-day-old newborn with cyanosis and respiratory distress was admitted. Intubation and catecholamine administration had already done. Blood pressure was 80/50 mmHg, heart rate was 160/min. Urine volume was only 7 ml per 4 hours with diuretics. The diagnosis of supracardiac type of TAPVD was done by echo cardiography. Without cardiac catheterization, emergent operation was performed. After median sternotomy, the mobilization of the aorta was done. Under cardiopulmonary bypass the aorta was retracted to the left, the superior vena cava to the right and the common pulmonary venous trunk (CPV) was identified through the transverse sinus. Parallel incision were made in the left atrium and CPV, and extended to the vertical vein. An anastomosis using continuous suture was fashioned. She had a good postoperative course. The superior approach through the transverse sinus affords excellent exposure of the CPV and left atrium in situ in the neonatal period, if the mobilization of the aorta is completed, and the heart is not compressed or displaced. This approach is useful for supracardiac type of TAPVD.

Female↗
PubMed1990

[A case of coronary sinus rupture following retrograde coronary perfusion for myocardial protection].

A 48-year-old woman was admitted to our hospital suffering from chest and back pain. The aortogram and CT scanning revealed aortic dissection (DeBakey II type). Six days after onset, the emergent operation was carried out under the cardio-pulmonary bypass. Myocardial protection was made by retrograde coronary sinus perfusion (RCSP) with cold GIK. The ascending aorta was replaced with an artificial graft including the entry. Massive bleeding in the pericardial space and the rupture of coronary sinus was recognized immediately after declamping of the aorta. Repair was made successfully under induced electric ventricular fibrillation. Care for RCSP was discussed.

Coronary Vessels↗
PubMed1989

Evidence for the formation of strand-break precursors in hydroxy-attacked thymidine 5'-monophosphate by the spin trapping method.

A method combining spin trapping, ESR, and HPLC was employed to obtain evidence for the formation of sugar radicals in OH-attacked TMP with special emphasis on the detection of strand-break precursors of DNA. OH radicals were produced by irradiating an N2O-saturated aqueous solution with X-rays. When an N2O-saturated aqueous solution containing TMP and a spin trapping reagent, MNP, was irradiated with X-rays, it was estimated on the basis of theoretical calculations using rate constants that 94% of the TMP radicals were induced by OH radicals. Since several spin adducts between TMP radicals and MNP, as well as the byproducts of the spin trapping reagent itself, were produced, reverse-phase HPLC was used to separate them. The presence of six spin adducts was confirmed by ESR examination. Further examination of these spin adducts by UV absorbance spectrophotometry showed the presence of a chromophore at 260 nm in three adducts. Since a gradual increase in the release of unaltered base from these adducts was observed when they were allowed to stand for 0-22 h at room temperature, they could be regarded as the spin adducts of sugar radicals and MNP. ESR spectra from the spin adducts were consistent with hydrogen abstraction radicals at the C1', C4', and C5' positions of the sugar moiety. These radicals appeared to be precursors of AP sites and strand breaks. In addition to these spin adducts, ESR spectra that were consistent with the spin adducts of base radicals (the C5 and C6 radicals) and MNP were observed.

Chromatography, High Pressure Liquid↗
PubMed1989

Detection of small displacement of atoms in crystals by atom resolution electron microscopy.

Four kinds of works on the detection of displacement of atoms in crystals are shown. The irregular small displacement of atoms has been detected, with an accuracy of about 0.1 A around dislocations and stacking faults in Au crystals as shown by their electron microscope images. The displacement of the atomic images is recorded by aberration-free focus (AFF). Even when the periodic displacement of atoms in SiC and TaS2 crystals is around 0.1% of the lattice constant, this displacement has been revealed as the weak-contrast anomaly in the images. Using in situ observations by a TV system attached to an electron microscope, the rapid movements of atoms that have taken place within 1/30 sec have been recorded. Using the technique of successive subtraction of the images by TV system and image sigma, only the images of moving atoms in Au crystal have been recorded each 1/10 sec.

Chemical Phenomena↗
PubMed1989

Induction of DNA double-strand breaks in Chinese hamster V79 cells by 2-chlorodeoxyadenosine.

2-Chlorodeoxyadenosine was found to induce DNA double-strand breaks as well as cell death in log-phase Chinese hamster V79 cells. The induction of DNA double-strand breaks, measured by a neutral elution technique, was observed after a 2-h incubation of the cells in the presence of 5 microM of 2-chlorodeoxyadenosine, but these breaks were almost rejoined by a subsequent 1-h incubation, even though this drug was present in the medium during incubation. This repair was prevented by the addition of nicotinamide, which is known to inhibit poly(ADP-ribose) synthesis that is strongly associated with the DNA ligation, but not prevented by the addition of 9-beta-D-arabinofuranosyladenine (araA), which is known to inhibit DNA polymerization. These results suggest that the repair of CdA-induced double-strand breaks is achieved by ligation alone without DNA polymerization. When 35 microM of cycloheximide and 1.3 mM of dibutyryl cAMP were added to the medium, it was found that the induction of double-strand breaks by 2-chlorodeoxyadenosine was suppressed, while the cytotoxicity of 2-chlorodeoxyadenosine measured by colony-forming ability was not interfered with. These results suggest that the induction of DNA double-strand breaks is not associated with the cytotoxicity of this drug.

2-Chloroadenosine↗
PubMed1989

Specific binding of a HeLa cell nuclear protein to RNA sequences in the human immunodeficiency virus transactivating region.

The transactivator protein, tat, encoded by the human immunodeficiency virus is a key regulator of viral transcription. Activation by the tat protein requires sequences downstream of the transcription initiation site called the transactivating region (TAR). RNA derived from the TAR is capable of forming a stable stem-loop structure and the maintenance of both the stem structure and the loop sequences located between +19 and +44 is required for complete in vivo activation by tat. Gel retardation assays with RNA from both wild-type and mutant TAR constructs generated in vitro with SP6 polymerase indicated specific binding of HeLa nuclear proteins to the TAR. To characterize this RNA-protein interaction, a method of chemical "imprinting" has been developed using photoactivated uranyl acetate as the nucleolytic agent. This reagent nicks RNA under physiological conditions at all four nucleotides in a reaction that is independent of sequence and secondary structure. Specific interaction of cellular proteins with TAR RNA could be detected by enhanced cleavages or imprints surrounding the loop region. Mutations that either disrupted stem base-pairing or extensively changed the primary sequence resulted in alterations in the cleavage pattern of the TAR RNA. Structural features of the TAR RNA stem-loop essential for tat activation are also required for specific binding of the HeLa cell nuclear protein.

Base Sequence↗
PubMed1989

OH-induced free radicals in purine nucleoside monophosphates: e.s.r. and spin-trapping.

Free radicals produced by the reactions of OH radicals with six purine nucleoside monophosphates (3'-AMP, 5'-AMP, 5'-dAMP, 3'-GMP, 5'-GMP and 5'-dGMP) were investigated by a method combining e.s.r. spin-trapping and high-performance liquid chromatography (HPLC). The N2O-saturated aqueous solutions of purine nucleoside monophosphates, containing 2-methyl-2-nitrosopropane as a spin-trap, were X-irradiated and the resulting spin-adducts were separated by reverse-phase HPLC in the ion suppression mode. The separated spin-adducts were characterized by e.s.r. spectrometry and UV spectrophotometry. Consequently, the radicals due to H-abstraction at the C4' position of the sugar moiety were identified arising from 5'-dAMP and 5'-dGMP. In all cases, e.s.r. spectra consisting of a secondary doublet were observed and assigned to the radical due to H-abstraction at the C5' position of the sugar moiety.

Chromatography, High Pressure Liquid↗
PubMed1989

[Clinical studies on TMJ arthrosis in young people. A study of dental axis of lower molar teeth].

The subjects were 37 female patients with juvenile TMJ arthrosis (T group) and 27 healthy females (N group) who visited the Dept. of Oral Surgery, Nagoya University Hospital or the Dept. of Dent-Oral Surgery, Nagoya University Branch Hospital. Following evaluations were made: 1) L6 to L7 angle 2) L6 to occlusal plane 3) L7 to occlusal plane 4) L6 to mandibular plane 5) L7 to mandibular plane 6) occlusal plane angle 7) mandibular plane angle Following results were obtained: 1. Significant differences between T group and N group were not seen in the occlusal plane angle. 2. A majority in the T group showed a mesial inclination of the lower second molar. 3. Mandibular plane angle in the T group was larger than that in the N group.

Adolescent↗
PubMed1989

Elevated glutathione accelerates oxidative damage to erythrocytes produced by aromatic disulfide.

It has been shown that certain dogs have erythrocytes characterized by an inherited high concentration of reduced glutathione (GSH), five to seven times the normal level (high-GSH RBCs). We examined whether increased GSH in dog erythrocytes leads to increased protection against oxidative damage induced by acetylphenylhydrazine (APH) and/or 4-aminophenyl disulfide (4-AD). When erythrocytes were incubated with 30 mmol/L APH, the Heinz body count was appreciably higher in normal RBCs than in high-GSH RBCs, while there was no difference in the increase of the methemoglobin (metHb) concentration in both RBCs. In contrast, both the Heinz body count and metHb production were much higher in high-GSH RBCs than in normal RBCs when erythrocytes were incubated with 4-AD. Furthermore, the generation of the superoxide in erythrocytes treated with 4-AD, which was measured by spin trapping combined with electron spin resonance (ESR), was obviously higher in high-GSH RBCs than in normal RBCs. These results clearly indicate that erythrocyte GSH is an important defense against oxidative damage induced by certain compounds such as APH, but that, in contrast, elevated GSH appears to accelerate oxidative damage to erythrocytes produced by aromatic disulfides, such as 4-AD, which generated a superoxide in erythrocytes via its redox reaction with GSH.

Aniline Compounds↗
PubMed1989

[A case of multiple sclerosing hemangiomas of the lung and a review of the literature in Japan].

A 39-year-old woman complained of an oppressive feeling in her chest and abnormal shadows were detected in the left lower lobe. On a preoperative diagnosis of primary or metastatic lung cancer, left lower lobectomy was performed. There were 3 nodular tumors in the left S6, S10 but no metastasis to regional lymph nodes was found. Histological examination confirmed "so-called" sclerosing hemangioma. She has remained well for 4 years after surgery. A review of the literatures on sclerosing hemangioma in Japan showed that 12 (5%) of 225 cases of sclerosing hemangiomas had multiple tumors.

Adult↗
PubMed1989

Cytotoxic effect of acyclovir on cultured mammalian cells to which herpesvirus thymidine kinase gene was introduced.

The cytotoxic effects of acyclovir, which is a purine nucleoside analogue and is known as an antibiotic substance, were examined on three lines of rat skin fibroblast FR cells; normal FR cells, FRtk- cells which are deficient in the activity of thymidine kinase (tk) and FRtk-HSVtk+ cells which were prepared by introducing herpes simplex virus' tk gene to FRtk- cells. When FRtk-HSVtk+ cells growing exponentially were incubated in the presence of acyclovir for 4 h, the surviving fractions of the cells decreased in a concentration-dependent manner. Whereas, decrease of the surviving fractions was almost indiscernible in both FR cells and FRtk- cells at the whole ranges of drug-concentrations tested. These results indicate that acyclovir is phosphorylated by the herpes simplex virus' tk and becomes toxic to FRtk-HSVtk+ cells. This also means that FRtk-HSVtk+ cells are useful for the investigation of the biological activity of nucleoside analogues.

Acyclovir↗
PubMed1989

[Basic and clinical evaluation of an immunoradiometric competitive inhibition assay for 2----6 sialyl Lewis a antigen--1. Evaluation of assay conditions and normal values].

We describe an immunoradiometric competitive inhibition assay of the serum levels of the 2----6 sialyl Lewisa antigen, using "SLA 2-6 Otsuka" kits. The assay required only duplicate 50-microliters samples, and the concentration of 2----6 sialyl Lewisa antigen in serum was determined by reference to a standard curve ranging from 0 to 160 arbitrary U/ml. The intra- and inter-assays reproducibilities were good and analytical recovery of antigen were excellent. The serum levels of the antigen were highly dependent on the Lewis blood types of the tested individuals; i.e., the levels of the antigen in the sera of the Lewisa-b- individuals were significantly lower than those of the antigen obtained with the Lewisa+b- and Lewisa-b+ individuals. The cut-off value (42 U/ml) was obtained as mean + 2SD, which was carefully calculated from the antigen levels in sera of the non-Lewisa-b- individuals.

Adult↗