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Biomedical subjects

N Ishizuka

Publications and source records attributed to N Ishizuka.

16 recordsLinked to original sources
PubMed1992

Echocardiographic findings and clinical features of left ventricular pseudoaneurysm after mitral valve replacement.

We studied the echocardiographic findings and clinical features of left ventricular pseudoaneurysm after mitral valve replacement. From December 1979 to March 1991, 1050 patients underwent mitral valve replacement at our institute, and eight patients (0.8%) had left ventricular pseudoaneurysm. In all eight patients, left ventricular pseudoaneurysm developed after the second mitral valve replacement. The incidence of left ventricular pseudoaneurysm among 253 patients who had had previous mitral valve surgery was 3.1%. Seven of the eight patients were still alive and were followed up from 5 to 136 months (mean, 57 months) after the development of left ventricular pseudoaneurysm; these patients had no complications. One patient died as a result of low cardiac output after mitral valve replacement in spite of repair of the left ventricular pseudoaneurysm. This patient had a long and wide myocardial laceration near the left ventricular pseudoaneurysm. In the other seven patients, transthoracic echocardiography demonstrated a large extraventricular cavity along the posterobasal left ventricle. In five of these patients, a turbulent flow in the neck of the left ventricular pseudoaneurysm was recorded both in systole and diastole by pulsed and color Doppler echocardiography. Transesophageal echocardiography clearly showed the narrow neck of the left ventricular pseudoaneurysm and an abnormal flow between the left ventricle and the left ventricular pseudoaneurysm. Generally, when left ventricular pseudoaneurysm develops after mitral valve replacement, surgical repair is the first choice of therapy. Our study demonstrated, however, that the development of left ventricular pseudoaneurysm was not always associated with a poor prognosis without surgical intervention.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

Na+,K(+)-ATPase inhibition by an endogenous peptide, SPAI-1, isolated from porcine duodenum.

SPAI-1, a peptide isolated from porcine duodenum, has been shown to inhibit Na+,K(+)-ATPase in vitro (Araki et al. (1989) Biochem. Biophys. Res. Commun. 164, 496-502). The characteristics of ATPase inhibition by this novel peptide were examined. SPAI-1 inhibited Na+,K(+)-ATPase preparations isolated from various organs of dog or rat or from sheep kidney with similar potency. Three isoforms of rat Na+,K(+)-ATPase had similar sensitivity to inhibition by SPAI-1 although these isoforms had remarkable differences in their sensitivity to the inhibitory effect of ouabain. Ca(2+)-ATPase isolated from the sarcoplasmic reticulum of rabbit skeletal muscle was insensitive to inhibition by SPAI-1. Ouabain-insensitive Mg(2+)-ATPase activity was unaffected by low concentrations of SPAI-1, but was stimulated at high concentrations. SPAI-1 inhibited H+,K(+)-ATPase from hog stomach in concentrations similar to that required for Na+,K(+)-ATPase inhibition. These results indicate that SPAI-1 is a specific inhibitor for monovalent cation transporting ATPases.

Adenosine Triphosphatases↗
PubMed1979

Trajectory of group Ia afferent fibers stained with horseradish peroxidase in the lumbosacral spinal cord of the cat: three dimensional reconstructions from serial sections.

A reconstruction was made of the intramedullary trajectory of 23 physiologically identified Ia afferents from cat hind limb muscles (medial gastrocnemius, soleus, plantaris, flexor digitorum-hallucis longus, and hamstring). The afferents were stained by intra-axonally injected HRP. The axons of these afferents were traced over distances of 5.8 mm to 15.7 mm rostrocaudally. In the dorsal funiculus fibers from all the muscles showed a similar course and similarly bifurcated into an ascending and a descending branch. The mean diameters of stem axons, ascending branches, and descending branches were 6.6 micrometer, 5.8 micrometer, and 3.0 micrometer, respectively. Within the analyzed lengths of the spinal cord five to eleven collaterals were given off from the two branches. The distances between adjacent collaterals of the ascending and descending branches averaged 1200 micrometer and 790 micrometer, respectively. The collaterals as a rule passed through the medial half of the dorsal horn before they entered the deeper parts of the gray matter. The terminal distribution areas common to all Ia collaterals were: (1) the medial half of the base of the dorsal horn, mainly lamina VI: (2) lamina VII; and (3) lamina IX. The numbers of terminals were largest in lamina IX and smallest in lamina VII. The density of terminals in lamina IX was highest in the homonymous motor cell column. The terminal distribution areas of adjacent collaterals showed no overlap in the sagittal plane. Terminal branches carried one bouton terminal and up to six boutons en passage with an average of 1.8 terminals per terminal branch. Apparent axosomatic and axodendritic contacts were seen on small-sized and medium-sized neurons in laminae V-VI, medium-sized neurons in lamina VII, and large neurons in lamina IX. One motoneurons was contacted by an average of 3.3 terminals. In addition to the common features, Ia collaterals of various muscles of origin showed some differences in their trajectories in the ventral horn, and in their terminations in the gray matter.

Animals↗
PubMed1978

Reconstruction of trajectory of primary afferent collaterals in the dorsal horn of the cat spinal cord, using Golgi-stained serial sections.

Using Golgi-stained serial sections obtained at the sacro-caudal levels of the cat spinal cord, it was possible to reconstruct the trajectory of primary afferents. They were classified into two groups: reliable primary afferents directly traced from the dorsal root and probable primary afferents traced from the dorsal funiculus or Lissauer's tract. The diameters of the reliable primary afferents vary from 0.88-1.88 mum. According to their courses, reliable primary afferents as well as probable primary afferents were classified into three groups: the first is distributed to both medial and lateral halves of the dorsal horn, the second to the medial half, and the third to the lateral half. Commissural fibers were also observed among the probable primary afferents. The rostro-caudal and medio-lateral extents of reliable primary afferents are found to be between 250 and 950 mum and 270 and 700 mum respectively, while those of the probable primary afferents were between 125 and 670 mum and 270 and 1,640 mum respectively. These primary afferent fibers are connected with at least two or more laminae of the dorsal horn gray matter.

Afferent Pathways↗
PubMed1978

Left ventricular function studies in constrictive pericarditis.

Left ventricular function studies were performed on five patients with constrictive pericarditis. Functional data were obtained from intracardiac pressure measurements and cineangiocardiographic films. Left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), ejection fraction (EF), stroke work index (SWI), circumferential fiber shortening, and percent circumferencial shortening were significantly below normal values in the five cases. These changes are reflected mainly in the degree of pericardial restriction. Reduction in mean Vcf was also observed. Theoretically, the velocity of ventricular internal circumferential shortening is also affected by changes in ventricular volume or resting myocardial fiber length, however, in patients with constrictive pericarditis, reduction in mean Vcf suggests left ventricular dysfunction. Our clinical studies indicate that evaluation of mean Vcf is valuable in the assessment of postoperative prognoses.

Adolescent↗
PubMed1977

Criteria of complete remission from trophoblastic neoplasia with the use of human chorionic gonadotropin (HCG) excretion pattern as a parameter.

The excretion pattern of human chorionic gonadotropin (hCG) or luteinizing hormone (LH) was observed in the urine of 77 patients with trophoblastic neoplasia, 109 with complete remission from trophoblastic neoplasia, and 94 with no trophoblastic neoplasia, when the anti-beta-subunit hCG system radioimmunoassay (anti-beta-subunit RIA), which specifically measured hCG was used. The sensitivity of anti-beta-subunit RIA was limited to urinary hCG 16 mIL/ml from the specificity of the anti-beta-subunit serum. Luteinizing hormone in the urine of patients with complete remission and in normal menstrual, postmenopausal, and castrated women was less than 16 mIU/ml in most cases. The excretion pattern of urinary hCG in the patients undergoing treatment for trophoblastic neoplasia was more clearly comprehended with the anti-beta-subunit RIA as compared with the anti-hCH RIA. The criteria for judgment of complete remission were that the hCG value dropped to less than 16 mIU/ml and that cellular response was not observed at least in the last two courses.

Adult↗
PubMed1976

Immunologic studies in patients with trophoblastic neoplasia.

Histocompatibility antigen was analyzed in 1,104 patients with trophoblastic neoplasia and in their husbands. Furthermore, the patients were examined for cell-mediated immunity. (1) There was no significant difference in the frequency of the ABO blood groups between patients with hydatidiform or destructive mole or choriocarcinoma and healthy persons. (2) The incidence of appearance of anti-HL-A antibody was more frequent in the patients with destructive mole than in those with hydatidiform mole or choriocarcinoma. (3) Patients with choriocarcinoma were frequently incompatible at HL-A9, HL-A10, and HL-AW5. (4) The mixed lymphocyte culture (MLC) showed lower values in patients with choriocarcinoma than in those with destructive mole. Histocompatibility between the patients and their husbands was more remarkable in the patients with chriocarcinoma than in those with destructive mole. (5) In patients with choriocarcinoma, incompatibility was detected at HL-A10, HL-A11, HL-AW5, and HL-A13 in the group with good prognosis and at HL-A5, HL-AW15, and HL-A12 in the poor prognosis group. The MLC value was lower in the poor prognosis group.

ABO Blood-Group System↗
PubMed1976

Cell-mediated immunity in pregnant women.

Phytohemagglutinin-induced lymphocyte transformation (PHA-T) was depressed in pregnant women, as compared with that in nonpregnant women. Pregnancy serum had a suppressive action on PHA-T which was enhanced with the advance in pregnancy. Hydrocortisone, progesterone, alpha-fetoprotein and trophoblast-specific antigen, were demonstrated as immune suppressive factors. From these results, it was concluded that cell-mediated immunity might be reduced in pregnant women and that this reduction might be one of the causes for the maintenance of pregnancy.

Antigens↗
PubMed1976

Innumoelectron microscopy of the human chorionic villus in search of blood group A and B antigens.

The chorionic villi of placentas, 10 to 40 weeks of gestation, were examined for A and B blood group antigens with an immunoferritin technique. No specific ferritin attachment was shown on the plasma membrane of the villous trophoblasts. Furthermore, after trophoblast cell-surface mucosubstances (perhaps the barrier of the placental antigenicity, according to some authors) were digested with several enzymes, such as neuraminidase, hyaluronidase, chondroitinase ABC, pepsin, trypsin, and pronase, no ferritin tagging was observed on the plasma membrane of the villous trophoblasts. We have concluded that our failure to detect the A and B blood group antigens was not due to the masking of antigens by mucosubstance coating the trophoblasts, but was due to the intrinsic deficit of those antigens in the plasma membrane of the human trophoblasts.

ABO Blood-Group System↗
PubMed1975

Radioligand receptor assay for urinary and serum hCG.

A radioligand receptor assay system for urinary hCG and serum hCG was developed, using 1100-2000 times g fractions of homogenates of pig testis. This method is specific for hCG and LH, and the limit of detection for hCG was 20 mIU, which could be significantly discriminated from zero at the 95% confidence level. A nonspecific inhibition reaction which exerts its influence on the assay system has been found in the urine and serum, and in performing assays for urinary and serum hCG, it was necessary to remove the inhibition reaction by diluting the urine more than eight fold or subject the serum to an extraction procedure. Since the hCG of normal pregnancy and trophoblastic neoplasia showed a dose response curve similar to that of the International Standard hCG, it became clear that these hCG could be assayed with this method. The potency ratio R/I measured by RRA and RIA of urinary hCG and serum hCG was different from those of normal pregnancy and trophoblastic neoplasia.

Animals↗
PubMed1975

Pregnancy and childbirth in a true hermaphrodite.

A rare case of pregnancy and parturition in a true hermaphrodite is reported. This patient, who was 25 years of age when first seen, had an ovotestis on the left and an ovary on the right gonad, with a karyotype of 46,XX. Following removal of the left ovotestis and surgical correction of the external genitalia, she married at the age of 31 and subsequently delivered a normal male child, karyotype 45,XY, by cesarean section.

Adult↗