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Biomedical subjects

T Yokoi

Publications and source records attributed to T Yokoi.

At least 235 records · Page 13Linked to original sources
PubMed1991

Establishment and characterization of immortalized non-transplantable mouse mammary cell lines cloned from a MMTV-induced tumor cell line cultured for a long duration.

During the culturing of a mouse mammary tumor cell line, MuMT73, maintained in vitro for more than a decade, we found morphological heterogeneity in its cells; some showed contact inhibition in their growth, some formed domes and some grew criss cross and piled up. In trying to clone the cell line to isolate cells showing contact inhibition or dome formation, we were able to establish six clonal cell lines. These six cell lines were categorically divided into three groups according to their phenotypical behavior, Groups A, B and C. Group A (clones 1, 5 and 7) cells had a property of contact inhibition. They induced no tumor when injected into the subcutaneous tissue of the back, nor even when injected into the mammary fat pads or under the kidney capsule of syngenic or nude mice, and therefore were thought to be non-malignant in nature. They were positively stained by anti-keratin antiserum and had mouse mammary tumor viruses (MMTVs). Group B (clone 6) cells grew in a crisscross pattern and piled up, and they induced tumors when injected into the subcutaneous tissue of the back of mice. Group C (clones 3 and 4) cells formed domes in their growth and induced some tumors in the mammary fat pads and under the kidney capsule of KSN nude mice. In Southern blots with MMTV-env probe, numerous exogenous MMTV proviruses were detected in these cell lines. The insertion patterns of these proviruses in cells of non-malignant clonal lines (Group A) resembled those of malignant lines (Group B), except one band (about 26 Kb), but were considerably different from those of intermediate lines (Group C). On the other hand, no difference was detected in Southern blots with int-1 or int-2 probes among the non-malignant, intermediate and malignant clonal cell lines.

Animals↗
PubMed1991

[A case of lupus nephritis with hyporeninemic hypoaldosteronism].

We report a case of 67-year-old woman with systemic lupus erythematosus presenting hyporeninemic hypoaldosteronism. She admitted because of anasarca in March, 1990. She manifested nephrotic syndrome, and hyperkalemia and hyperchloremic metabolic acidosis. The hyperkalemia was disproportionate to the degree of renal insufficiency. Basal levels of plasma renin activity and plasma aldosterone concentration were low. Renal tubular function studies revealed normal hydrogen ion secretion. Renal biopsy demonstrated diffuse proliferative lupus nephritis and prominent interstitial cell infiltration. There was no vasculitis of glomerular vascular poles. After treatment of lupus nephritis with prednisolone, levels of plasma renin activity and plasma aldosterone concentration were elevated. Hyperkalemia and metabolic acidosis were normalized and renal function improved. We conclude that the heperkalemia and metabolic acidosis could be attributed to hyporeninemic hypoaldosteronism.

Acidosis↗
PubMed1991

[A case of apyretic miliary tuberculosis which was discovered accidentally].

A 78 year-old female was referred to our hospital, because diffuse miliary shadows in bilateral lung fields were discovered during upper G.I. series. She did not complain of fever or display any chest symptoms. Her laboratory data on admission revealed mild hypoxemia and high serum CA 19-9. The transbronchial lung biopsy specimen proved epithelioid cell granulomas. M. tuberculosis was observed on culture from the sputa, urine and bronchoalveolar lavage fluid. She was diagnosed to have miliary tuberculosis, and antituberculous drugs were administered. After the antituberculous therapy, the diffuse miliary shadows on the chest X-ray diminished gradually, and the laboratory data improved. No elevation in the body temperature was seen during the entire clinical course. Though it is known that miliary tuberculosis in elderly patients is often atypical and has mild symptoms, miliary tuberculosis without fever is very rare.

Age Factors↗
PubMed1991

[Paternity test with single locus DNA probes].

Seven kinds of DNA probes recognizing hypervariable DNA loci were applied to 28 cases of paternity test, involving two cases in which the putative fathers had died. The combinations of probe and restriction enzyme are as follows; MR24/1-HinfI, 3'Globin-PvuII, Ha-ras-PvuII, Mucin-PvuII, D2S44 (pYNH24)-MspI, D17S30 (pYNZ22)-MspI, D1S57 (pYNZ2)-RsaI. The reported number of the alleles are 37, 39, 5, 10, 33, 15, and 5, respectively. Those probes lie on different chromosomes except D1S57 on 1p and Mucin on 1q21. Exclusion probability (EP) and paternity index (PI) were calculated from the allele frequencies in Japanese population reported by Yokoi et al. Cumulative EP from 7 DNA probes was 0.999932, and cumulative PI ranged from 7.3 X 10(6) to 947. Also, cumulative EP from 17 kinds of conventional blood group markers (CBGM) was 0.9776, and cumulative PI ranged from 1290 to 0.11. Total EP from 7 DNA probes and CBGM was 0.999998478. Cumulative PI from 7 DNA probes were 5 to 2,000,000 times higher than that from CBGM. The single locus hypervariable DNA polymorphisms are considered to be informative for paternity test.

DNA Probes↗
PubMed1991

[New analysis algorithm for regional cerebral blood flow and partition coefficient with dynamic SPECT and N-isopropyl-p-[123I]iodoamphetamine: graphical plot method].

We developed a new analysis algorithm based on multiple-time graphical plot to estimate the regional cerebral blood flow and partition coefficient using dynamic SPECT and N-isopropyl-p-[123I]iodoamphetamine (123I-IMP). By assuming the 2-compartment model of the kinetic for 123I-IMP, we derived a linear relationship between the ratio of the tissue activity concentration at the times to the time-integral arterial concentration at the respective times (formula; see text) and the ratio of the time-integral tissue concentration to the time-integral arterial concentration (formula; see text), and demonstrated that the Y-intercept and X-intercept of the plot line represent the regional cerebral blood flow (K1) and partition coefficient (lambda), respectively. The slope of the line represents a clearance constant k2. The present method was applied to data on four normal subjects measured by dynamic SPECT. Values of the K1 and lambda for the gray matter were obtained 40.8 +/- 6.5 ml/100 g/min and 28.8 +/- 5.3 ml/g, respectively, and the corresponding values for the white matter were 29.1 +/- 4.7 ml/100 g/min and 28.1 +/- 7.1 ml/g. The new method enabled a rapid estimation of both K1 and lambda.

Algorithms↗
PubMed1990

Role of interleukin 6 for differential responsiveness of naive and memory CD4+ T cells in CD2-mediated activation.

The present study was undertaken to elucidate different requirements for CD2-mediated activation of naive (CD45RO-) and memory (CD45RO+) CD4+ T cells. A mitogenic combination of anti-CD2 (anti-T11(2) and anti-T11(3] mAbs could effectively induce the proliferation of memory CD4+ T cells even in the absence of monocytes. In marked contrast, naive CD4+ T cells did not disclose any proliferative responses to anti-CD2 mAbs, when monocytes were absent in culture. This differential responsiveness of naive and memory CD4+ T cells appeared to be related largely to a difference in IL-6-producing ability between both populations. IL-6 among monocyte-derived cytokines could correct unresponsiveness of naive CD4+ T cells to anti-CD2 stimulation. Unlike naive CD4+ T cells, memory CD4+ T cells produced IL-6 by themselves, with its mRNA being expressed on anti-CD2 stimulation. Anti-IL-6R mAb significantly inhibited proliferation of memory CD4+ T cells seen in the anti-CD2-stimulated cultures without monocytes, indicating the involvement of their own production of IL-6 in CD2-mediated activation. The results suggest an essential role of IL-6 for triggering of CD4+ T cells via the CD2 molecule.

Adult↗
PubMed1990

Detection by in situ hybridization and phenotypic characterization of cells expressing IL-6 mRNA in human stimulated blood.

IL-6 has manifold biologic functions in immune and inflammatory responses and is produced by a variety type of cells. In this work, we used the whole blood culture to identify the cells expressing IL-6 gene/protein after various stimulation. When the whole blood was incubated with LPS or Con A, much IL-6 activity, measured by the growth promoting assay using a murine IL-6-dependent hybridoma clone, was detected in the plasma as early as 4 h of culture and continued to increase with time, reaching a plateau around 12 h. Immunocytochemical analysis with anti-rIL-6 antiserum revealed that a proportion of mononuclear cells (MNC) contained intracytoplasmic IL-6 in LPS- or Con A-stimulated blood. Northern blot analysis for MNC from the blood stimulated with these stimuli showed that their transcripts for IL-6 peaked at 4 h, then rapidly declined and was undetectable after 24 h of stimulation. In situ hybridization technique with radiolabeled antisense RNA probe for IL-6 demonstrated that a fraction of MNC from LPS- as well as Con A-stimulated blood expressed IL-6 mRNA. With the combined use of in situ hybridization and immunofluorescence by corresponding mAb, it was confirmed that IL-6 mRNA expressing cells in stimulated blood were exclusively monocytes. In the whole blood culture, it was shown that expression of IL-6 mRNA by monocytes was inhibited by dexamethasone, but not by cyclosporin A. These results suggest that monocytes are the major cells expressing IL-6 gene/protein in the circulation after exposure to external stimuli.

Antigens, CD↗
PubMed1990

Characterization of cell fusion in XC cells induced by Suncus murinus mammary tumor virus.

Syncytium formation in a rat tumor cell line (XC) induced by Suncus murinus mammary tumor virus (Sm-MTV) was studied. Multinucleate giant cells containing 20-30 nuclei were formed in a monolayer of XC cells by cocultivation with X-ray-irradiated Sm-MTV producing cells (Sm-MT-1). By fluorescent antibody staining. Sm-MTV antigens were demonstrated in the cytoplasm of syncytia, and budding particles and intracytoplasmic A particles were found in syncytial giant cells by electron microscopy. Cell-free supernatant of Sm-MT-1 was capable of inducing syncytia at a much lower incidence than cocultivation of Sm-MT-1 cells. Syncytium formation was completely inhibited when anti-Sm-MTV bovine serum was added to the coculture medium. Pretreatment of XC cells with actinomycin-D caused a partial reduction of Sm-MTV-induced cell fusion, but syncytium formation did occur at a reduced rate even when cellular RNA synthesis was completely inhibited. Dexamethasone increased virus production in Sm-MT-1 cells, resulting in the enhancement of Sm-MTV mediated syncytium formation. Sm-MTV was found to have a unique characteristic of cell fusion activity on XC cells with striking enhancement by dexamethasone.

Animals↗
PubMed1990

Hypervariable polymorphic VNTR loci for parentage testing and individual identification.

Three kinds of variable number of tandem repeat DNA probes (VNTR: pYNZ22, pYNH24, and pYNZ2) showing hypervariable polymorphisms were studied. Allelic frequencies and their confidence intervals among Japanese individuals were obtained. Co-dominant segregation of the polymorphism was confirmed in family studies. Two a priori probabilities were calculated for each VNTR locus: exclusion probabilities for an alleged father/mother/child trio and for an alleged parent/child duo, and probabilities of matching of genotyped two unrelated individuals or two siblings. Availability as well as highly discriminating polymorphic pattern of VNTR loci makes it potentially very useful for forensic and human genetic purposes.

Alleles↗
PubMed1990

Investigation of paternity establishing without the putative father using hypervariable DNA probes.

Seven kinds of DNA probes which recognize hypervariable loci were applied for paternity test. The putative father was decreased and unavailable for the test. The two legitimate children and their mother (the deceased's wife) and the four illegitimate children and their mother (the deceased's kept mistress) were available for analysis. Paternity index of four illegitimate child was investigated. Allelic frequencies and their confidence intervals among unrelated Japanese individuals were previously reported from our laboratory, and co-dominant segregation of the polymorphism was confirmed in family studies. Cumulative paternity indices of four illegitimate children from 16 kinds of standard blood group markers were 165, 42, 0.09, and 36, respectively. On the other hand, cumulative paternity indices from 7 kinds of DNA probes are 2,363, 4,685, 57,678, and 54,994, respectively, which are 14, 113, 640, 864, and 1,509 times higher than that from standard blood group markers. The DNA analyses gave nearly conclusive evidence that the putative father was the biological father of the children. Especially, the paternity relation of the third illegitimate child could not be established without the DNA analyses. Accordingly, DNA polymorphism is considered to be informative enough for paternity test.

DNA↗
PubMed1990

Haptoglobin typing of human bloodstains using a specific DNA probe.

The stability of DNA in human bloodstains and various post mortem tissues has been investigated. High molecular weight (HMW) DNA was usually recovered from dried bloodstains, even those up to a few years old, but very rapid degradation was found to occur post mortem in the liver, pancreas, spleen and kidney. Other tissues such as the heart, thyroid and skeletal muscle were found to give a reasonable yield of HMW DNA during the first few days after death. The feasibility of using DNA extracted from forensic bloodstain specimens for the detection of DNA polymorphisms was explored using a human haptoglobin (Hp) alpha chain specific probe. Using HindIII and XbaI digests the Hp genotypes Hp2, Hp1F and Hp1S were distinguished by Southern blot analysis in DNA prepared from 1 cm2 bloodstains up to 15-18 months old.

Autoradiography↗
PubMed1990

The capability of neonatal leukocytes to produce IL-6 on stimulation assessed by whole blood culture.

IL-6 is a cytokine with a wide variety of influences on the cells involved in immune and inflammatory responses. Defective production of IL-6 may be partly responsible for the impaired immune defense and inflammatory response often observed in the neonatal period. In our study, we used whole blood culture to examine the capacity of neonatal leukocytes to produce IL-6 in response to various stimuli. IL-6 activity was evaluated by growth promoting assay using an IL-6-dependent murine hybridoma clone. IL-6 activity was undetectable in fresh or unstimulated blood obtained from both newborns and adults. In contrast, incubation of whole blood with lipopolysaccharide or concanavalin A resulted in marked IL-6 activity. After stimulation, IL-6 activity was induced as early as 2 h after culture and increased with time, reaching a plateau at around 12 h. Comparative examinations suggested that the IL-6 activity induced in neonatal blood on stimulation was similar to that seen in stimulated adult blood. Neutralization experiments with anti-IL-6 anti-serum confirmed the presence of IL-6 proteins in the stimulated blood, and induction of cellular IL-6 mRNA was demonstrated in the stimulated blood as well. In addition, immunocytochemical observations suggested that the major IL-6 producing cells in the stimulated blood may be monocytes. The results suggest that the production of IL-6 in response to specified stimuli is normal at birth.

Adult↗
PubMed1990

Individual identification of human bloodstains investigated with hypervariable DNA loci.

Seven kinds of hypervariable DNA probes, which recognize hypervariable loci, were applied for individual identification of human bloodstains. Allelic frequencies and their confidence intervals among unrelated Japanese individuals were previously reported from our laboratory, and codominant segregation of the polymorphism was confirmed in family studies. One-month-old bloodstains from ten individuals were investigated in the present study. The probability of matching was calculated using the database among Japanese population. Cumulative probability of matching from 7 kinds of hypervariable DNA probes was 1.1 x 10(-11), which was 4.5 x 10(9) times higher than that from 6 kinds of common blood group markers such as ABO, MN, Rh-Hr, P1, Hp and PGM1. Accordingly, DNA polymorphism is considered to be informative enough for individual identification of bloodstains.

Alleles↗
PubMed1990

Hypervariable regions of DNA for parentage testing and individual identification.

Four kinds of DNA probes that recognize hypervariable regions (HVR) were studied for parentage testing and individual identification. Allele frequencies and their confidence intervals among unrelated Japanese individuals were obtained. Codominant segregation of the polymorphism was confirmed in family studies. Two a priori probabilities were calculated for each HVR locus: the exclusion probabilities for an alleged father/mother/child trio and for an alleged parent/child duo, and the probabilities of matching of genotypes of two unrelated individuals or two siblings. The ease of availability of the probes and their highly discriminating polymorphic patterns mean they could be very useful for forensic purposes.

Alleles↗
PubMed1990

Epstein-Barr virus-immortalized B cells produce IL-6 as an autocrine growth factor.

The continuous proliferation of Epstein-Barr virus (EBV)-immortalized B cells is enhanced by autocrine as well as paracrine growth factors. In the present study, the possibility that EBV-immortalized B cells might produce interleukin-6 (IL-6) proteins in an autocrine manner was examined. It was found that culture supernatants from EBV-transformed B cells, but not from Burkitt's lymphoma lines, augmented the proliferation of an IL-6-dependent murine hybridoma clone, MH60.BSF2. This growth-promoting activity for hybridoma cells found in culture supernatants of EBV-transformed B cells was specifically neutralized by rabbit anti-recombinant (r) IL-6 antibody. The IL-6 activity in culture supernatants of EBV-transformed B cells, though much less than that of lipopolysaccharide (LPS)-stimulated monocytes, was increased by the addition of phorbol myristate acetate. Western blot experiments using rabbit anti-rIL-6 antiserum demonstrated that supernatants from cultured EBV-transformed B cells contained the distinct forms of IL-6, with a peak of 23,000 MW. When examined by in situ hybridization analysis, it was found that IL-6 mRNA were expressed on EBV-transformed B cells. It was noted that a fraction, but not all, of these cells expressed IL-6 mRNA strongly, implying their cell cycle-dependent expression. In addition, it was shown that rIL-6 promoted the growth of EBV-transformed B cells at low cell densities. The results suggest that IL-6 serves as an autocrine growth factor in EBV-transformed B cells.

B-Lymphocytes↗
PubMed1990

Immune status in two brothers with Omenn's syndrome: no discernible chimerism on FACS analysis using a monoclonal antibody specific for a maternally restricted HLA antigen.

Sequential immunologic examinations, including lymph node biopsies, in two brothers with clinical characteristics of Omenn's syndrome are presented in this study. Although the number of circulating T cells with mature phenotype (OKT3+, TCR1+) was within normal range, the lymphocyte proliferative response to mitogens was poor. Examinations of the lymph nodes revealed marked lymphoid depletion associated with eosinophilic infiltration and reticular cell proliferation. Over the clinical course of 5 months, circulating T cells also mostly disappeared. Thymic hypoplasia was noted at autopsy. Although intrauterine graft-versus host disease (GVHD) has been hypothesized as being the pathogenetic mechanism in this syndrome, maternal lymphocytes circulating in these patients were not identified either by karyotype and HLA typing or by highly sensitive FACS analysis and immunohistochemical studies using a monoclonal antibody, HLA-A9, specific for a maternally restricted HLA antigen, Aw24. In conclusion, the familial occurrence and the absence of maternal chimerism might be the essential features of Omenn's syndrome which should be differentiated from fetal GVHD.

Antibodies, Monoclonal↗
PubMed1990

[A fast technique to estimate local cerebral blood flow and partition coefficient using dynamic PET of H(2)15O: a new approach to weighted integration method based on time integration of Kety-Schmidt equation].

We developed a new technique for fast estimation of local cerebral blood flow and partition coefficient based on time integration of Kety-Schmidt equation. This technique has two advantages concerning statistical noise. Firstly, it does not need a Ci(T) image which contains high statistical noise because of low activity in brain. Secondly, statistical noise is minimized by time integration of Kety-Schmidt equation before multiplied by weighting function. The error analyses in flow and partition coefficient caused by statistical noise were performed using computer simulation, and dynamic PET human study using H(2)15O bolus injection. Both simulation and PET study indicated that uncertainties of flow and partition coefficient were confirmed to be lower in this technique than in the original weighted integration method.

Brain↗