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Biomedical subjects

K Yasui

Publications and source records attributed to K Yasui.

At least 253 records · Page 14Linked to original sources
PubMed1992

[A case of multiple pulmonary metastases from duodenal cancer showing partial response using 5'-DFUR and a small dose of MMC].

A 77-year-old female with primary duodenal cancer had undergone pancreatoduodenectomy in May, 1989. Postoperative chemotherapy was done in combination with MMC (mitomycin C), lentinan and UFT (combined medicine of tegafur and uracil). In August, 1991, the patient complained of a cough and then was examined for multiple pulmonary metastases from duodenal cancer by chest X-ray and CT-scan. Then, she received 5'-DFUR (400-800 mg) and MMC (total 6 mg). Two months from the start of this therapy, the cough almost vanished and pulmonary lesions were diminished markedly. For about five months, this case corresponded to partial response (PR) according to the response criteria proposed by Koyama-Saitoh. The side effects of 5'-DFUR were diarrhea and anorexia. Therefore, we think that 5'-DFUR and a small dose of MMC yielded a partial response to multiple pulmonary metastases from duodenal cancer.

Adenocarcinoma↗
PubMed1991

[Low flip-angle spin-echo imaging of the liver. Basic study and its application to hepatic space-occupying lesions].

Dependence on T1 contrast can be reduced by changing the excitation flip angle. Low flip-angle spin-echo imaging can reduce imaging time because repetition time (TR) is reduced. The authors assessed the efficacy of low flip-angle spin-echo images in phantoms and in liver. MR phantoms made from polyvinyl alcohol gel to model the properties of normal liver, HCC, and hemangioma were scanned with various flip angles at TR 2400 and 1200 msec. Measured signal intensities fitted well with theoretical values. The T1 contrast of signal intensity decreased as the flip angle was reduced, accompanied by a decrease in signal-to-noise ratio (S/N). Thirty patients with hepatic space-occupying lesions (23 with HCC, three with metastases and four with hemangioma) were studied by conventional SE (CSE) at 2400/60/2 (TR/TE/NEX [number of excitations]) (10 min 46 sec imaging time) and low flip-angle SE (LFSE) at 1200/60/30 degrees/2 (TR/TE/FA/NEX) (5:20) and/or 1200/60/30 degrees/4 (10:18). The sensitivity of CSE in detecting lesions was 93% (44/47). It was 92% (35/38) for LFSE with two NEX and 94% (34/36) for LFSE with four NEX pulse sequences. The contrast-to-noise ratio (C/N) for images (HCC/liver, hemangioma/liver) obtained by LFSE with four NEX was significantly higher than that for those obtained by CSE (4.8 vs 3.5, p less than 0.01; 13.4 vs 9.7, p less than 0.01, respectively). Although the C/N (lesion/liver) for LFSE with two NEX sequences was lower than that of CSE for any type of lesion (3.0 vs 3.5 for HCC; 5.1 vs 6.3 for metastases; 8.3 vs 9.7 for hemangioma), the difference was not significant. Although reducing the flip angle from 90 degrees to 30 degrees with two NEX resulted in a decrease in S/N (10.7 to 8.9 for HCC; 15.3 to 11.9 for metastases; 20.0 to 18.1 for hemangioma; 7.4 to 6.3 for normal liver; 10.7 to 10.1 for spleen), the difference was not significant. For hepatic space-occupying lesions, low flip-angle spin-echo imaging is useful to obtain T2-weighted images in a shorter imaging time without sacrificing lesion detectability.

Adult↗
PubMed1991

Acute effects of intravenous nicardipine on hemodynamics and cardiac function in patients with a healed myocardial infarction and no evidence of congestive heart failure.

Acute effects of intravenous nicardipine (10 micrograms/kg) on systemic hemodynamics and cardiac function were evaluated in 17 patients with a healed myocardial infarction and no evidence of congestive heart failure. Mean New York Heart Association functional class was 1.6 +/- 0.5 (mean +/- standard deviation). Aortic systolic pressure (p less than 0.001) and left ventricular end-diastolic pressure decreased (10 +/- 3 to 8 +/- 3 mm Hg, p less than 0.01), and systemic vascular resistance decreased significantly (p less than 0.001), whereas pulmonary and right atrial pressure and pulmonary arteriolar resistance did not change. Cardiac and stroke indexes showed biphasic changes. Although positive and negative maximal rate of left ventricular pressures decreased significantly (p less than 0.05 and p less than 0.01, respectively), they did not change significantly when aortic systolic pressure was corrected. There was a significant inverse correlation between the negative rate of left ventricular pressure/aortic systolic pressure before nicardipine infusion and its maximal percent increase after infusion (r = -0.56, p less than 0.05), indicating a beneficial effect on diastolic relaxation in patients with impaired diastolic function. Our data show that a low dose (10 micrograms/kg) of intravenous nicardipine exerts a favorable effect on impaired diastolic function, but depresses left ventricular pump function with much less effect on right heart circulation.

Adult↗
PubMed1991

[Examination for quantitative evaluation of abnormality of regional pulmonary blood flow in patients with diffuse pulmonary diseases--an application of bull's eye analysis].

Bull's eye analysis was applied to the 99mTc-MAA lung perfusion scintigraphy (planar or SPECT). Three kind of phantoms were used to examine spatial and density resolution. Filling defect of 3 cm in diameter was detected and 30% difference between one RI concentration and the other was also detected by this method. 99mTc-MAA lung perfusion scintigraphy was performed in 39, including 28 with diffuse pulmonary diseases and 11 normal subjects. Bull's eye image with its circumferential profile curve was compared visually with conventional planar or SPECT image. This method was superior or equal to conventional image in 78% (planar) and in 75% (SPECT). Especially in patients with interstitial pneumonia, 94% was superior or equal. The patient's Bull's eye map was compared with the lower limit of normal (mean-2SD), and the extent score (ES) and the severity score (SS) were calculated. The changes of ES and SS was useful to follow up the clinical course of the patients. This method would be effective to evaluate the regional pulmonary blood flow quantitatively.

Adult↗
PubMed1991

Expression of synaptophysin during synapse formation between dissociated cortical neurons.

Cerebral cortical cells from fetal rats (14 days) were cultured in vitro (7-104 days). Localization of synaptophysin was examined immunocytochemically using a monoclonal antibody (SY-38) against synaptophysin. Synaptophysin-immunoreactive (SP-IR) spots were distributed on the surface of the cells. Electron-microscopic observation showed that the SP-IR staining was localized at presynaptic terminals, indicating that the SP-IR spots observed will, fluorescence microscopy represent presynaptic terminals. The time-course of the distribution of SP-IR spots was examined. SP-IR spots could not be observed in cells at 7 days in vitro (DIV). At 14 DIV, SP-IR spots could be first observed on the surface of cell bodies and neurites. Thereafter, the density of SP-IR spots on the cell bodies and neurites increased with DIV. At 42 and 104 DIV, SP-IR spots were almost continued, surrounding the neurites and cell bodies of the cultured cells. These immunocytochemical studies suggest that the dissociated 14-day fetal cerebral cortical neurons make synapses by at least 14 DIV and that the density of synapses increases with time.

Animals↗
PubMed1991

Establishment and characterization of a new spontaneous metastasis model of human gastric carcinoma in nude mice.

A poorly differentiated medullary carcinoma of human stomach, designated HY-1, was successfully transplanted to nude mice by either the subcutaneous or intramuscular route for five generations. The transplanted tumor showed spontaneous lung metastases in nearly 100% of KSN and Balb/c female nude mice. There were over 20 visible lung metastatic nodules in KSN and Balb/c nude mice bearing tumors for over 80 days. Immunostaining of type IV collagen and electron microscopy revealed that tumor cells were often in direct contact with basement membrane (BM) of tumor blood vessels in the primary tumor tissue. At the site of contact between tumor cells and vascular BM, focal disappearance of the BM, disruption of endothelial cells and entry of tumor cell clusters into vascular lumen were observed. Immunostaining of 72 kDa gelatinase/type IV collagenase demonstrated that tumor cells expressed this enzyme in their cytoplasm. These results suggest that spontaneous metastasis of this tumor may be partly due to a marked tendency to vascular invasion involving the following sequential events: tumor cell contact with vascular BM, BM degradation possibly by 72 kDa gelatinases and endothelial disruption. This model could be a useful tool for understanding the mechanism of hematogenous metastasis of human gastric cancer.

Aged↗
PubMed1991

Requirement of the conformational stability of a Salmonella ribosomal vaccine for its mouse protection.

The 43-kDa non-O antigenic component isolated from the crude ribosomal fraction of Salmonella typhimurium [9] was further purified by affinity chromatography (43-kDa protein: 43-kDp). Immunization with 43-kDp did not induce complete mouse protection in CF1 mice to 500 LD50 of S. typhimurium, although it elicited a substantial IgG antibody response. The 43-kDp exhibited the mitogenicity to splenocytes (CF1 and C3H/HeJ) and B cell-rich populations (CF1). Complexing 43-kDp with the compact ribosomes of Streptococcus pyogenes by formaldehyde (complex vaccine: CV) elicited both IgM and IgG antibodies to 43-kDp. CV induced a boosting effect to enhance IgG antibody response. Moreover, CV generated delayed-type hypersensitivity to salmonella antigens and also conferred complete protection against 500 LD50 challenge of S. typhimurium to CF1 mice. These abilities of CV were reduced or impaired by RNase digestion. CV was able to induce partial or complete protection in inbred mouse strains (C3H/HeN, C3H/HeJ, DBA/2 and A/J). These data, in addition to other reports, suggest that conformational stability between ribosomes and contaminating substances such as 43-kDp or O-antigens might be required for the overall effects of the ribosomal vaccine.

Animals↗
PubMed1991

Japanese encephalitis virus neurotropism is dependent on the degree of neuronal maturity.

In a study on Fischer rats, all animals infected with Japanese encephalitis virus (JEV) before the age of 13 days died, but animals infected after the age of 14 days did not die, confirming the age-dependent resistance to JEV infection in the rat brain. A study of the kinetics of JEV infection in the developing rat brain disclosed that JEV antigen disappeared in a particular pattern, i.e., from the deeper layers to the upper layers of the motor cortex, which paralleled neuronal maturation in the cortex. Fifteen-day-old rats, which were resistant to JEV infection, received intracerebral transplants of neurons taken from 19-day embryos. When these animals were infected with JEV after transplantation, viral antigen was detected only in the embryonal neurons soon after transplantation. Thus, it can be concluded that the susceptibility to JEV infection in the rat brain is closely associated with neuronal immaturity.

Aging↗
PubMed1990

Hormonal regulation of soluble immune response suppressor (SIRS): a possible role of SIRS in the maintenance of pregnancy.

This study was conducted to investigate the effects of sex hormones upon the nature of soluble immune response suppressor (SIRS) produced by concanavalin A-stimulated Lyt-2+ T cells. Conventional SIRS affected IgM PFC only. However, SIRS made with progesterone (20-400 ng/ml or Prog-SIRS) suppressed IgM PFC, one-way MLR, and generation CTL; and SIRS made with estrogen (0.2-50 ng/ml or Est-SIRS) enhanced these responses. The factor(s) (MW 40,000-55,000) to stimulate macrophages to produce the second soluble factor (M phi-SF) was isolated from all preparations by gel filtration. Furthermore, Est-SIRS contained a factor(s) (MW 10,000-30,000) to enhance IgM PFC, MLR, and mitogen-induced blastogenesis of both T and B cells; and Prog-SIRS possessed the suppressive factor(s) to IgM PFC, MLR, and mitogen-induced T-cell proliferation. These activities were not impaired by 2-mercaptoethanol. Moreover, the suppressive activity of Prog-SIRS was completely absorbed by T cells only, but the enhancing activity of Est-SIRS was not completely absorbed by a single-cell population. These data suggest that progesterone can contribute to the suppression of allograft rejection through soluble factors, and estrogen can enhance host responses which may be affected by several soluble factors during pregnancy.

Animals↗
PubMed1990

Is potassium co-transported by the cardiac Na-Ca exchange?

It has been suggested that the stoichiometry of the electrogenic Na-Ca exchange is 3Na:1Ca. Recently, however, it was reported in rod outer segments that the stoichiometry of Na-Ca exchange is not 3Na:1Ca but 4Na:1Ca + 1K. In cardiac cells, the reversal potential has always been measured in the absence of K or at a very low K concentration. We have, therefore, re-examined the reversal potential of the Na-Ca exchange current by whole-cell voltage clamp in single guinea-pig ventricular cells in the presence of K on both sides of the membrane. The Na-Ca exchange current reversed at potentials close to the calculated values for 3Na:1Ca stoichiometry even in the presence of K. The magnitude of the Na-Ca exchange current did not change in 1 and 10 mM [K]o. We therefore conclude that K is not co-transported by cardiac Na-Ca exchange and its stoichiometry is 3Na:1Ca.

Animals↗
PubMed1990

New two-dimensional, echocardiographically directed pericardiocentesis in cardiac tamponade.

Seventeen patients with cardiac tamponade were treated by pericardiocentesis guided by two-dimensional (2-D) echocardiography and a needle guide. The needle guide used in the present study was designed so that the needle path lies within the center of the scan thickness. Before actual puncture, the mask method was performed in a water bath so that the needle progress avoided injury. The needle progress was monitored continuously in real time on the display throughout the procedure. Immediate relief from acute cardiac tamponade was obtained in all except one patient, who was treated by pericardiotomy because of insufficient drainage. In two patients, second drainage was performed because of reaccumulation of the pericardial effusion. There were no major complications. Nine patients recovered and the other patients died of underlying disease. Accurate and efficient visualization of the needle might allow a safer procedure. We conclude that pericardiocentesis guided by 2-D echocardiography using a needle guide may be a safe and easily applied technique for the management of pericardial effusion.

Adult↗
PubMed1990

An increase in polymorphonuclear leucocyte chemotaxis accompanied by a change in the membrane fluidity with age during childhood.

Leucocyte membrane fluidity affects cell deformability as well as the accessibility of receptors and the degree of their exposure on the membrane. These effects modulate the subsequent cellular responsiveness. We have assayed membrane fluidity of polymorphonuclear leucocytes of children, using an excimer-forming lipid technique in flow cytometry, and evaluated its relation to their chemotaxis to a formyl peptide. We report that membrane fluidity and chemotaxis of polymorphonuclear leucocytes are increased with age. These findings may have important implications for the physiological processes in polymorphonuclear leucocyte motility during childhood.

Adult↗
PubMed1990

Induction of protective immunity in animals vaccinated with recombinant vaccinia viruses that express PreM and E glycoproteins of Japanese encephalitis virus.

A cDNA clone representing the genome of structural proteins of Japanese encephalitis virus (JEV) was inserted into the thymidine kinase gene of vaccinia virus strains LC16mO and WR under the control of a strong early-late promoter for the vaccinia virus 7.5-kilodalton polypeptide. Indirect immunofluorescence and fluorescence-activated flow cytometric analysis revealed that the recombinant vaccinia viruses expressed JEV E protein on the membrane surface, as well as in the cytoplasm, of recombinant-infected cells. In addition, the E protein expressed from the JEV recombinants reacted to nine different characteristic monoclonal antibodies, some of which have hemagglutination-inhibiting and JEV-neutralizing activities. Radioimmunoprecipitation analysis demonstrated that two major proteins expressed in recombinant-infected cells were processed and glycosylated as the authentic PreM and E glycoproteins of JEV. Inoculation of rabbits with the infectious recombinant vaccinia virus resulted in rapid production of antiserum specific for the PreM and E glycoproteins of JEV. This antiserum had both hemagglutination-inhibiting and virus-neutralizing activities against JEV. Furthermore, mice vaccinated with the recombinant also produced JEV-neutralizing antibodies and were resistant to challenge with JEV.

Amino Acid Sequence↗
PubMed1990

Enhanced interleukin production after long-term administration of erythromycin stearate.

The effects of erythromycin stearate (10 mg/kg/day) were studied on productions of interleukin (IL)-1 and -2 in mice after a long-term treatment. A 28-day treatment resulted in higher levels of IL-1 production by macrophages and of IL-2 production by splenocytes, while a 7-day treatment did not increase them. T-cell growth factor activity of IL-2 preparation prepared on day 28 of treatment as determined by HT-2 cell proliferation was reduced by about 40% in the presence of anti-murine IL-4 monoclonal antibodies, while control IL-2 activity was not reduced. Furthermore, a 28-day treatment with erythromycin stearate increased concanavalin A-induced blastogenesis of splenocytes significantly. These results suggest that long-term treatment with erythromycin stearate can stimulate host defense by increasing interleukin production.

Animals↗
PubMed1990

[A new application of bull's-eye analysis to lung perfusion scintigraphy].

Technetium-99m macroaggregated albumin lung perfusion scintigraphy was performed and evaluated semiquantitatively by bull's-eye analysis in 24, including 7 with central pulmonary carcinoma, 3 with hypersensitivity pneumonitis (HP), 3 with diffuse panbronchiolitis (DPB) and 11 normal subjects. First, whole lung field was divided into three regions by three concentric circles. And then radial axes were projected from the center to define 36 sectors, 10 degree each. The counts of each sector was calculated and bull's-eye image and circumferential profile curve were displayed. The patient's map was compared with the lower limit of normal (mean-2 SD), and the extent score (ES) and the severity score (SS) were calculated. The ES was 0.25 +/- 0.12 in pulmonary carcinoma (n = 7), 0.08 +/- 0.07 in HP (n = 3), 0.06 +/- 0.04 in DPB (n = 3). The SS was 26.39 +/- 15.17 in pulmonary carcinoma, 4.75 +/- 5.57 in HP, 4.29 +/- 3.67 in DPB. In one case of central pulmonary carcinoma, segmental perfusion defect was evaluated semiquantitatively by bull's-eye image and circumferential profile curve. And in one case of HP, the change of regional pulmonary blood flow could be followed easily using extent and severity map. This new application of Bull's eye analysis to lung perfusion scintigraphy might be useful to evaluate regional pulmonary blood flow.

Alveolitis, Extrinsic Allergic↗
PubMed1990

Analysis of Japanese encephalitis (JE) virus genome and implications for recombinant JE vaccine.

From the information of nucleotide sequences and deduced amino acid sequences of flaviviruses including JEV, we can postulate processing mechanisms of a polyprotein translated from single long open reading frame of the genome and mechanisms of construction of antigenic structures of structural proteins with biologically active forms after these proteins are translated. The results of comparative analysis of amino acid sequences among flaviviruses and epitope analysis on the E proteins which are the most important antigens for protective immunity suggest that the E protein of flaviviruses may have a similar structure closely related to each other. PrM and E proteins which had predictable signal sequences upstream on the N terminals were expressed with antigenically active form and molecular size the same as the authentic ones by the recombinant viruses. However, the recombinant viruses which had no such signal sequence expressed unprocessed proteins with antigenically denatured forms. These results suggest that normal proteolytic processing is needed to construct biologically active structures of JEV structural proteins. The E proteins which were expressed by the recombinant viruses as antigenically active form could elicit nutralizing and HI antibodies in animals and protective immunity in mice. The recombinant vaccinia viruses which express the E protein could induce strong immunologic memory against the E protein in mice. These results indicate that the development of a new type of vaccine against JEV will become possible in future.

Amino Acid Sequence↗
PubMed1990

Nonspecific stimulation of host defense by Corynebacterium kutscheri. II. Isolation of the active moiety.

The isolation and determination of biological activities of the active component of Corynebacterium kutscheri were attempted in the present investigation. The antitumor effect was confined to the subcellular particle fraction of this bacterium and was associated with a molecule of glycoprotein nature (40,000-38,000 Daltons) isolated from this fraction by affinity chromatography with concanavalin A-Sepharose 4B. This substance exerted mitogenic activity on C3H/HeJ splenocytes and T cells, stimulatory activity on macrophages, and further exhibited antitumor effect on P388 leukemia in CDF1 mice. The Winn assay disclosed that the antitumor effect induced by this substance was dependent on L3T4+ T cells. Furthermore, both the mitogenic and antitumor activity of this moiety were resistant to heating at 100 degrees C for 30 min or RNase digestion, but sensitive to trypsin digestion, or low or high pH. These results indicate that the antitumor effect of C. kutscheri is attributable to the heat-stable glycoprotein moiety which can directly stimulate T cells and macrophages.

Animals↗