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Biomedical subjects

Y Nishikawa

Publications and source records attributed to Y Nishikawa.

At least 217 records · Page 12Linked to original sources
PubMed1991

[Left atrial booster pump function in left ventricular blood filling: clinical and experimental analyses].

Left atrial booster pump function produces variable effects on cardiac output. Generally, cardiac output decreases by only 15-20% when atrial fibrillation occurs, however, in some cases, hemodynamic collapse occurs through loss of left atrial contraction. We evaluated the relative significance of left atrial booster pump function in acute or chronic load and in myocardial ischemia using the left ventricular volume curve. Blood entering into the left ventricle during the left atrial contraction phase (FVLA) represents the left atrial volume work, and the ratio of FVLA to the left ventricular filling volume during one cardiac cycle (%FVLA) represents the relative significance of left atrial booster pump function in cardiac output. In dog experiments, we calculated the change in FVLA and %FVLA by measuring the the left ventricular internal minor axis diameter and using Pombo's method. We also measured the change of the left atrial segment length as a direct indicator of left atrial contraction. In the acute change in preload, FVLA changed with stroke volume, but %FVLA remained unchanged. The change in FVLA correlated with the direct indicator of the left atrial excursion; the extent of the left atrial segment length (LASL). During acute change of left ventricular afterload, both FVLA and %FVLA were unchanged. In regional myocardial ischemia, both FVLA and %FVLA were increased, suggesting an increase in the left atrial booster pump function. In clinical study, we calculated FVLA and %FVLA from the left ventricular diameter using M-mode echocardiography. In chronic volume overloading (aortic regurgitation), FVLA increased while %FVLA was maintained unchanged. The same FVLA-%FVLA relationship was observed in acute volume loading. In cases of left ventricular hypertrophy (LVH) and old myocardial infarction (MI), both FVLA and %FVLA were increased, suggesting the increased left atrial booster pump function. In these cases, the left ventricular rapid filling velocity decreased, suggesting that impairment of rapid filling caused the increase of left atrial preload and hence increased left atrial volume work. The results of this study show that in old MI and in LVH, both left atrial volume work and the relative significance of left atrial booster pump function increase. We concluded that prevention of atrial fibrillation may be very important in these diseases.

Animals↗
PubMed1991

[Results of open heart surgery in neonates--comparison between profound hypothermia with circulatory arrest and deep hypothermic bypass].

To investigate factors affecting surgical outcome of open heart surgery in neonates, a retrospective review was carried out on 38 patients operated in the 9 years period from May 1981 to August 1990, in our institution (TAPVR19, TGA7, HLHS7, and others 5). In the former 3 years and 9 month period, 12 patients were operated with the use of profound hypothermia and circulatory arrest (Group I) and in the latest 5 year and 5 month period, continuous deep hypothermic bypass was used in all but for 7 patients with HLHS (Group II). In the group of neonates with TAPVR, operative mortality improved to 7% (1 of 14) in Group II compared to that of 60% (3 of 5) in Group I. CVP and LAP measured immediately after cessation of cardiopulmonary bypass (CPB) were lower in Group II and the value of CPK-MB was significantly lower in Group II. There was a significant negative correlation (r = -0.695, p less than 0.05) between CPB time and urine volume for 72 hours after operation. A significant negative correlation (r = -0.899, p less than 0.01) was also obtained between CPB time and urine volume in the group of 7 neonates with TGA. There was no significant difference in urine volume between patients with TAPVR and TGA despite of significantly longer CPB time in patients with TGA. It is concluded that, 1) improved protection of cardiac and renal function was obtained in neonates operated with the use of continuous deep hypothermic bypass, 2) surgical outcome was influenced by the method of CPB, CPB time and differences in cardiac function ascribed to primary lesions.

Assisted Circulation↗
PubMed1990

Subtype-specific cyclic AMP-dependent histone H1 phosphorylation at the differentiation of mouse neuroblastoma cells.

At the initial phase of cell differentiation in mouse neuroblastoma (N18) induced by dibutyrylcyclic AMP (dbcAMP), an additional site of histone H1 was extensively phosphorylated. Forskolin and various phosphodiesterase inhibitors also induced both cell differentiation and H1 phosphorylation at the identical site. The phosphorylation preferentially occurred in a single H1 subtype (H1c) among the five (H1a-e) fractionated by high performance liquid chromatography. The three H1 subtypes of N18 (H1c, H1d, and H1e) were phosphorylated in vitro, and their amino acid sequences of the phosphopeptides were identical to the known sequence of rabbit H1 peptides containing a serine 37 residue. However, the amount of H1a and H1b phosphorylations was negligible. The serine residue was replaced by threonine residue in H1a, and H1b did not have a homologous peptide. The tryptic phosphopeptides of H1 in N18 were identical to that in rat liver H1 induced by glucagon (Langan, T.A. (1969) Proc. Natl. Acad. Sci. USA 64, 1276-1283). The results indicate that 1) the response of H1 subtypes to cAMP-dependent protein kinase in vivo and in vitro is H1 subtype-specific, and 2) the H1c phosphorylation may play an important role in the restrictive area of chromatin in both cell differentiation and hormonal stimulation mediated by cAMP.

1-Methyl-3-isobutylxanthine↗
PubMed1990

Elucidation of amidating reaction mechanism by frog amidating enzyme, peptidylglycine alpha-hydroxylating monooxygenase, expressed in insect cell culture.

A frog 'peptidylglycine alpha-amidating monooxygenase (PAM, EC 1.14.17.3)' was expressed in cultured insect cells by using the baculovirus expression vector system. The enzyme, recovered in the culture medium, was purified to homogeneity. Its apparent molecular mass (43 kd), estimated by both SDS-PAGE and molecular sieving, was higher than the value (39 kd) for the 'PAM' (AE-I) purified from frog skin. N-terminal sequence analysis indicated that cleavage of signal sequence had occurred but the propeptide still remained at the N terminus. The glycine-extended model peptide X-Gly (mean = Ala-Ile-Gly-Val-Gly-Ala-Pro) was used as substrate for the purified enzyme. The reaction product formed at pH 5.4 was isolated and characterized by amino acid sequence analysis, FAB-MASS and 1H-NMR. It was shown that the purified enzyme had converted the model peptide to the C-terminal alpha-hydroxyglycine-extended peptide [X-Gly(OH)] instead of the amidated product (X-NH2), indicating that the enzyme widely known as 'PAM' should be called 'peptidylglycine alpha-hydroxylating monooxygenase'. A novel enzyme, present in the insect cell culture medium and separable from the expressed monooxygenase, could convert the alpha-hydroxyglycine-extended peptide to the amidated product at physiological pH values. It is concluded that the alpha-amidation of glycine-extended peptides is a two-step process catalyzed by the monooxygenase and the novel enzyme.

Amino Acid Sequence↗
PubMed1990

Cor triatriatum, coarctation of the aorta, and ventricular septal defect: a rare, surgically correctable anomaly.

A case of cor triatriatum associated with coarctation of the aorta and ventricular septal defect, successfully treated surgically by a staged approach, is reported. This combination is a very uncommon but potentially correctable cause of congestive heart failure and death in infancy. Early accurate diagnosis aided by an awareness of this combination and prompt surgical correction should yield excellent long-term results.

Aortic Coarctation↗
PubMed1990

Genotypic differentiation of intrahepatically transplanted hyperplastic nodule cells of analbuminemic and normal rat origin by polymerase chain reaction.

DNA fragments encompassing the region of the seven-base-pair deletion in the albumin gene, which is a characteristic abnormality of Nagase's analbuminemic rat (NAR), were amplified by polymerase chain reaction, and we could differentiate the genotypes of normal rat, homozygous NAR and heterozygous NAR electrophoretically. This genotyping method was applied to the differentiation of hyperplastic nodules on immunostained tissue sections in the intrahepatic transplantation model. When the hyperplastic nodule cells of normal rat were transplanted to the livers of homozygous NAR, the donor cells were effectively differentiated from the host cells by the genotype.

Albumins↗
PubMed1990

Screening of aquatic samples for Vibrio cholerae serotype O1 by a dot-blot method and a latex agglutination test.

A dot-blot, enzyme-linked immunosorbent method and a latex agglutination test were studied for their abilities to detect Vibrio cholerae serotype O1 in aquatic samples by testing artificially contaminated water as well as samples from natural potential sources. Water samples were preenriched with alkaline peptone and then enriched with Monsur peptone water. For the dot-blot test, enriched cultures of organisms in a small portion of the Monsur peptone water were transferred to a polyvinylidene difluoride membrane with a microfiltration apparatus. The enzyme-linked immunosorbent assay was performed by using biotin-labeled antibodies and avidin-biotin-peroxidase complex; brown dots developed in the wells that contained serotype O1 vibrios. Latex agglutination tests were performed by mixing 1 drop of the culture in Monsur with 1 drop of reagent coated with monoclonal antibody specific for antigen A. The sensitivities and specificities of the methods were compared with those of the colony-blot method, which identified individual colonies of V. cholerae O1 in mixed bacterial cultures on isolation media. Our results indicate that the dot-blot method is as sensitive as the colony-blot method and is useful for screening for V. cholerae serotype O1 even in specimens that are heavily contaminated with non-O1 vibrios.

Humans↗
PubMed1990

[Results of surgical treatment of proximal hypospadias].

Eighteen patients of proximal hypospadia underwent operations by our two-stage method. First stage operation was done by exaggerated Nesbit's method. The foreskin was transposed to the ventral surface of the penis as a flap that is long enough to be brought to the top of the glans. The second-stage procedure was done after a minimum of 6 months. The urethral tube was formed around the Foley catheter with a flap, its peripheral end being one to two centimeters proximal to the sulcus. For one to two centimeters the distal flap was freed. The tubularization was done by a continuous 4-0 nylon suture, which was removed after ten days. The tube was passed to the top of the glans through the tunnel and sutured to the glans with 5-0 nylon. Urinary diversion was not performed. In one case the new urethral orifice receded and reoperation was done. The operations in the other 17 cases were successful without stricture or fistula formation.

Adult↗
PubMed1990

[Is the clinical course of non-rheumatic aortic regurgitation the same as that of rheumatic aortic regurgitation?].

To determine whether non-rheumatic (NR) aortic regurgitation (AR) has the same clinical and postoperative courses as rheumatic (R) AR, we performed a retrospective study using pre- and postoperative M-mode echocardiograms in 23 patients who underwent aortic valve replacement (AVR) under myocardial protection with hypothermic cardioplegia. The etiology of AR was diagnosed by two-dimensional echocardiography. The NR-AR group consisted of nine patients including four with aortic valve prolapse (AP) and five with bicuspid valve (BV), and the R-AR group included 14 patients. Patients with preoperative end-diastolic dimensions (EDD) of less than 6.0 cm were excluded from this study. The indication for AVR was NYHA functional class III or severer. The severity of preoperative NYHA functional class was similar among these three groups. During the 18-month follow-up period (range 2-32 months), there were no post-operative deaths nor congestive heart failure. Ages at surgery ranged from 17 to 54 years; 10 (71%) of 14 patients with R-AR were 40 years old or older, while seven (78%) of nine with NR-AR were under 39 years old (p less than 0.05). The pre-operative left ventricular end-diastolic pressure (LVEDP) in patients with BV-AR was highest among these three groups (R-AR: 14.5 +/- 3.9 mmHg, AP-AR: 9.5 +/- 4.1 mmHg, BV-AR: 22.0 +/- 2.7 mmHg, p less than 0.05). There was no significant difference in pre-operative M-mode echocardiographic results, except for the end-systolic dimension (ESD) between R-AR (5.20 +/- 0.55 cm) and BV-AR (4.78 +/- 0.18 cm) (p less than 0.05). The EDD one month after AVR was still abnormal (greater than or equal to 5.4 cm) in seven of the 14 patients with R-AR, and three of the four patients with AP-AR but none of the patients with BV-ARs (p less than 0.05 vs AP-AR). All patients with pre-operative ESD of less than 5.2 cm had normal EDD one month after AVR. In conclusion, the clinical course of NR-AR is different from that of R-AR. Furthermore, AP-AR regresses more differently after AVR than does BV-AR. Therefore, it is important to consider the etiology of chronic AR in determining the timing of surgery.

Adolescent↗
PubMed1990

[Cor triatriatum associated with coarctation of the aorta and VSD].

A case of cor triatriatum associated with coarctation of the aorta (CoA) and VSD is reported. A 4-month-old boy underwent subclavian flap aortoplasty and ligation of PDA with the diagnosis of CoA and VSD. At the age of 1 year and 2 months, echocardiography revealed an abnormal subdividing membrane in the left atrium. Under the definite diagnosis of cor triatriatum (Lucas & Schmidt type I B1) and VSD, complete removal of the abnormal septum, patch closure of ASD and VSD was performed with the aid of cardiopulmonary bypass, blood cardioplegia and topical cardiac cooling. Postoperative course was uneventful and the patient was discharged from the hospital on the 38th postoperative day. An association of cor triatriatum, VSD, and coarctation of the aorta is very rare, and to our knowledge, the case presented here seems to be the first report of successful total correction by a staged approach in the literature.

Aortic Coarctation↗
PubMed1990

[Biochemical analysis of bone and mineral metabolism in liver cirrhosis].

We investigated the disorder of bone and mineral metabolism in 29 patients with liver cirrhosis who were classified into two subgroups with (group 1, n = 13) or without (group 2, n = 13) osteopenia according to the method of Jikei. Serum levels of osteocalcin level, bone-type alkaline phosphatase activity and calcium concentration in serum and urine in these patients and 25 normal control subjects were determined. Serum osteocalcin level and bone-type alkaline phosphatase activity were elevated in group 1 compared with those in group 2 and normal control subjects. Serum and urine calcium levels in group 1 were similar to those in group 2. However calcium-creatinine ratio in urine was higher in group 1 than in group 2. These present observations indicate that osteopenia in patients with liver cirrhosis is due to high turnover of bone metabolism.

Adult↗
PubMed1990

Ring chromosome 21 transmitted from mother to daughter: its stability in a lymphoblastoid cell line.

A female infant with a high-pitched cry and hypertelorism but an otherwise normal facies was found to have the karyotype 46,XX,r(21)(p11.2q22.3). The r(21) was transmitted from the phenotypically normal mother. In both cases, the structure and behavior of the r(21) were rather stable in peripheral lymphocyte cultures. This stable nature of the r(21) was also confirmed in a lymphoblastoid cell line derived from the proband, where the normal-sized r(21) was persistent in most cells in prolonged culture for at least 5 months.

Abnormalities, Multiple↗
PubMed1989

Morphological studies on cerebral cortical lesions induced by transient ischemia in Mongolian gerbil--diffuse and peripheral pallor of the neuronal perikarya.

Unilateral transient cerebral ischemia was produced in Mongolian gerbils by clipping the left common carotid artery for 1 h. About 60% of the gerbils with neurological symptoms had post-ischemic seizures. The majority of those that had seizures died within a few days, and sections of their cerebral cortices contained many dark and shrunken neurons. However, the gerbils that did not have seizures survived without any severe complications. In the cerebral cortex of the latter, the neurons with diffuse or peripheral pallor of the perikarya were seen along with a small number of dark and shrunken neurons. Diffuse pallor occurred within a few hours following ischemia in layers III, V, and VI, and disappeared 1 or 2 days after recirculation. Electron microscopically, these neurons showed dispersion of ribosomes, simple and elongated profiles of rough endoplasmic reticulum (r-ER), clustered vacuoles, and mild to moderate mitochondrial swelling. Occasional net-like tubulomembranous structures, probably derived from r-ER, were observed. On the other hand, peripheral pallor became apparent after 5 days following ischemia, usually involving layer II first and gradually extending to the deeper layers. Concomitantly, the amount of neuropil decreased and the dendrites exhibited tortuosity and irregularity in layer II. Electron microscopically, these neurons showed marked swelling of peripheral perikarya and polyribosomes and organelles were located peripherally to the nuclei. In addition, numerous degenerated axon terminals and distended dendrites were observed around the neurons. These observations indicate that diffuse pallor represents damage directly induced by ischemia and subsequent recirculation, while peripheral pallor is the delayed and remote effect of ischemia, probably due to degeneration of neuronal processes.

Animals↗
PubMed1989

A rapid cross-sectioning and freeze-clamping device for the beating canine heart.

A new sampling method of cross-sectioning the canine heart in situ was developed. A mechanical device, driven by spring power, enabled cross-sectioning of a short-axis plane of the beating canine heart (4 mm thick) with high speed rotating blades, at a pre-determined phase of the cardiac cycle, and instantaneous freeze-clamping (2.4 mm thick) with pre-cooled aluminum blocks, all within 120 ms. By this method, the anatomical structures of the sample were well preserved. Transmural metabolism and flow distribution were instantaneously fixed and high resolution of the two-dimensional redox state was obtained by application of NADH fluorescence photography. Micro-samplings from the desired portion of the cross-sectional slice were possible at -190 degrees C. NADH fluorescence of the samples did not increase from the surface to 1.2 mm in depth, confirming that there was no ischemic artifact. With the present technique, a heart sample in which transmural metabolism, and the redox state, are fixed and visualized is attainable, thus providing a new tool for the study of myocardial ischemia.

Adenine Nucleotides↗
PubMed1989

Epidemiological study of occupational exposure to hepatitis B virus and liver function tests.

A total of 1020 hospital employees were divided into an exposure group (n = 725) and a non-exposure group (n = 295), based on whether they had been exposed to blood from patients. The HBsAg-positive rates for the exposure and the non-exposure groups were 2.48% and 1.02%, respectively. In the exposure group, the minimal exposure rate increased with age from the twenties. The odds ratios were 7.39 in the technicians, 4.38 in physicians and 1.32 in nurses. Using age-sex matched pairs from the exposure and non-exposure groups, comparison of aspartate aminotransferase, alanine amino-transferase and guanase activities showed that there were significantly higher values in HBsAg-positive subjects (n = 18) from the exposure group than in HBsAg- and HBsAb-negative subjects from the non-exposure group (p less than 0.05-0.01). However, no significant differences were found in the enzyme activities in the matched pairs (n = 89) of HBsAb-positive subjects from the exposure and non-exposure groups.

Adult↗
PubMed1989

Acrylamide derivatives as antiallergic agents. 2. Synthesis and structure-activity relationships of N-[4-[4-(diphenylmethyl)-1-piperazinyl]butyl]-3-(3-pyridyl)acryl amides.

A new series of 3-(3-pyridyl)acrylamides 16, 17, 19, and 26, and 5-(3-pyridyl)-2,4-pentadienamides 20-25 were prepared and evaluated for their antiallergic activity. Several of these compounds exhibited more potent inhibitory activities than the parent compound 1a [(E)-N-[4-[4-(diphenylmethyl)-1-piperazinyl]butyl]-3- (3-pyridyl)acrylamide] against the rat passive cutaneous anaphylaxis (PCA) reaction and the enzyme 5-lipoxygenase. Particularly, (E)-N-[4-[4-(diphenylmethyl)-1-piperazinyl]butyl]-3- (6-methyl-3-pyridyl)acrylamide (17p) showed an ED50 value of 3.3 mg/kg po in the rat PCA test, which was one-fifth of ketotifen and oxatomide. As compared with ketotifen and oxatomide, compound 17p (AL-3264) possessed a better balance of antiallergic properties due to inhibition of chemical mediator release, inhibition of 5-lipoxygenase, and antagonism of histamine.

Acrylamides↗