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Biomedical subjects

D Chia

Publications and source records attributed to D Chia.

At least 19 recordsLinked to original sources
PubMed1992

Appearance of the tumor marker CA 19-9 in liver transplant patients during rejection episodes.

The tumor marker CA 19-9 was shown to be elevated in liver transplant patients, particularly during rejection. Serial serum samples taken from 24 patients after liver transplantation were examined for tumor markers CA 19-9, SLEX, CEA, and TNF-alpha. During rejection, 85% of the patients had elevated levels of CA 19-9. Patients with early rejection had persistently higher levels than patients without rejection. The serum levels were low in nonrejecting patients compared with those with rejection. Thus, the CA 19-9 marker cannot be considered a specific tumor marker. It may, however, be an indicator of an immune response or it may be a byproduct of an inflammatory reaction to a tumor or a transplant.

Antigens, Tumor-Associated, Carbohydrate↗
PubMed1992

Accuracy in diagnosis of ectopic pregnancy by transvaginal ultrasonography.

Forty patients suspected to have ectopic pregnancy by transvaginal ultrasonography had surgery. 77.5% were confirmed to have ectopic pregnancy and 10% had other abnormal pelvic findings. The transvaginal approach appears to enable us to diagnose ectopic pregnancy at an earlier date, with the earliest diagnosis made at 4 weeks 0 days of amenorrhoea. In cases of confirmed ectopic pregnancy, the presence of a complex adnexal mass was the most common feature seen on transvaginal ultrasound and its predictability of ectopic pregnancy is enhanced by a concomitant finding of an empty uterus (95%) or free fluid in the Pouch of Douglas (94%) in the presence of a positive hCG test. The significance of transvaginal ultrasound features, and the advantages of transvaginal over transabdominal ultrasound, are discussed.

Female↗
PubMed1992

A case report: vesico-rectal fistula with ano-urethral atresia.

Vesico-rectal fistula is a rare congenital abnormality causing severe early second trimester oligohydramnios. Prenatal diagnosis of such a case is reported here. Ultrasound diagnosis could be aided by transabdominal amnio-infusion and, if necessary, fetal intraperitoneal saline installation. In a karyotypically normal fetus with normal somatic growth, demonstration of normal fetal kidneys together with a functioning urinary bladder, in presence of severe oligohydramnios, is very suggestive of the diagnosis. Since pulmonary hypoplasia is the major cause of neonatal mortality in these cases, restoration of normal amniotic fluid volume by serial amnio-infusion was attempted. Although amnio-infusion is an important diagnostic aid in the evaluation of severe midtrimester oligohydramnios, the role of multiple therapeutic amnio-infusion in improving lung growth remains to be evaluated.

Abnormalities, Multiple↗
PubMed1992

Amniocentesis and its complications.

This study was conducted in order to evaluate whether the performance of an experienced operator had any significant influence in reducing the incidence of complications in amniocentesis; 1,459 women had amniocentesis performed under ultrasound guidance; 1,324 were performed by experienced operators and 135 cases by less experienced operators. Complications like fetal loss, blood-stained amniotic fluid, culture failure, multiple needle puncture, leaking liquor, fetal trauma and error in results were compared in the 2 groups. This study demonstrated that amniocentesis performed by an experienced operator decreased the various complications associated with amniocentesis.

Amniocentesis↗
PubMed1992

Umbilical artery blood flow in intra-uterine growth retarded fetuses and fetal outcome: a study of 102 cases.

The 102 fetuses diagnosed by ultrasound to be asymmetrically growth-retarded had blood flow velocity waveforms of the umbilical artery studied. Sixty-two cases had normal blood flow, 28 had abnormal blood flow but with present end-diastolic flow, 8 had absent end-diastolic flow, and 4 had reversal of end-diastolic flow. Comparison was made between the blood flow status and other biophysical methods of antenatal surveillance and perinatal outcome. There is a strong correlation between abnormal blood flow and abnormalities detected by other biophysical methods of antenatal surveillance. Our study shows that fetuses with severe blood flow impairment tend to be more severely growth-retarded and to be delivered earlier. Our results also show abnormal blood flow to be associated with a poor perinatal outcome. Those fetuses with severe impairment of blood flow suffered a high incidence of operative delivery for fetal distress, acidosis at birth, perinatal mortality and morbidity. The association between abnormal blood flow and the 5-minute Apgar score is significant only in those with the severest impairment of blood flow. Our results are in close agreement with similar studies recorded in the literature.

Apgar Score↗
PubMed1991

Binding of IgG to B cell via HLA molecules.

Binding of immunoglobulins to major histocompatibility complex (MHC) molecules was demonstrated by two different assays: the binding of IgG to B cells by flow cytometry, and purified MHC antigens with an Elisa assay. Fc fragment from immune-complex binds to the Fc receptor on B lymphocytes. Here, Fab was also shown to bind to B cells. This binding was inhibited by specific human allo anti-HLA Class I and II sera directed at the polymorphic sites. Thus, in addition to the Fc receptor, MHC can also serve as a binding site for IgG. In an Elisa assay using purified antigens, IgG was shown to bind to HLA Class I and II molecules. Other proteins such as transferrin, human serum albumin, gelatin, etc., did not bind to the MHC proteins. Immunoglobulins bound to MHC molecules by sites on the Fab fragment independent of the hypervariable region. This was demonstrated by the retention of antibody activity even after binding of antibody (anti-lactoferrin) to MHC. The relative avidity between Fab and HLA Class I and II was 4-8 x 10(5) M-1.

B-Lymphocytes↗
PubMed1990

The role of tumor necrosis factor in allograft rejection. I. Evidence that elevated levels of tumor necrosis factor-alpha predict rejection following orthotopic liver transplantation.

Plasma levels of tumor necrosis factor-alpha were measured in 50 adult patients following orthotopic liver transplantation. The mean (+/- SEM) plasma concentration of TNF-alpha was significantly higher in patients experiencing a rejection episode (941 +/- 83 pg/ml) than in those with a stable clinical course (240 +/- 6 pg/ml; P = 0.0001). Peak levels of TNF-alpha were usually found at the time of clinically diagnosed rejection, although elevated levels were observed 1-2 days earlier. First-week peak TNF-alpha levels were significantly higher in patients who suffered graft loss (2146 +/- 788 pg/ml) than in those who were discharged from the hospital without clinical evidence of rejection (581 +/- 93 pg/ml; P = 0.004). TNF-alpha levels were not correlated with white blood cell count (r2 = 0.004), cyclosporine levels (0.01), serum creatinine (0.002), serum bilirubin (0.05), serum SGOT (0.03), or SGPT (0.05). TNF-alpha levels were not elevated in four cases of viral hepatitis occurring after transplantation. We conclude that circulating levels of TNF-alpha are elevated during liver allograft rejection and may precede clinical manifestations. First-week TNF-alpha levels are also useful predictors of long-term graft outcome. Further investigation is required to determine whether this monokine is important in the actual pathogenesis of allograft rejection.

Adolescent↗
PubMed1979

Characterization and measurement of anti-IgG antibodies in human sera by radioimmunoassay (RIA).

A sensitive direct binding radioimmunoassay (RIA) was developed which detected low avidity anti-IgG antibodies in sera negative in the latex fixation test (LFT). IgG class antibodies could be detected and were commonly found along with IgM class antibodies. Additionally, the RIA was more reproducible than the LFT, was easily adapted to measure relative avidities of anti-IgG antibodies, and had other technical advantages over the LFT.

Antibodies, Anti-Idiotypic↗
PubMed1979

Quantitation and characterization of soluble immune complexes precipitated from sera by polyethylene glycol (PEG).

Polyethylene glycol (PEG) was used to isolate immune complexes from sera. Complexes were then quantified and partially characterized by a variety of immunological techniques. Complexes were detected in rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), Felty's syndrome and vasculitis, but not in polymyositis, scleroderma or Behçets syndrome. The level of immune complexes correlated with disease activity in SLE and RA patients. Rheumatoid factors and anti-DNA antibodies were enriched by PEG precipitation of RA and SLE sera, respectively, thus these antibodies appeared to be present in the form of soluble immune complexes. Immune complexes usually contained all three immunoglobulin classes, IgG, IgM and IgA. Complexes from RA patients were generally larger and often contained Clq, while C3 was found almost exclusively in SLE complexes which also tended to be smaller. Such compositional differences may one day explain the differences in clinical manifestations of various immune complex-mediated diseases.

Antibodies, Antinuclear↗
PubMed1979

IgM anti-IgM cold lymphocytotoxins to B cells.

Cytotoxic antibodies to B lymphocytes have been shown to be IgM. They are not absorbed by red blood cells and therefore not absorbed by red blood cells and therefore not directed against the I antigen of red cells. They are also not inhibited by mannose, as are certain natural cytotoxins against lymphocytes. Methods for producing purified eluates of IgM anti-IgM antibodies are given. These antibodies are postulated to be immunoregulative by acting on B lymphocytes.

Absorption↗
PubMed1979

A simple, rapid micro-latex fixation test.

A micro-latex fixation test (LFT) for the determination of rheumatoid factor (RF) is presented. Its advantages compared to similar tests are greater precision, simplicity, increased sensitivity, lower cost, reproducibility and adaptibility to large-scale testing. Micro-LFT titres are presented from a wide range of sample populations. The majority of normal samples show measureable titres whereas rheumatoid patients show high titres. A large sampling of pre- and post-transplant sera from kidney patients was studied and the micro-LFT titres were in the range of normal persons. The transplant sera were tested for lymphocytotoxic antibodies and no correlation was observed with the micro-LFT titres.

Adult↗
PubMed1979

The metabolism of nucleic acids in mice.

The metabolism of three forms of nucleic acid, native-DNA (N-DNA), single strand DNA (SS-DNA), and polyinosinic-polycytidylic acid (poly I : C), was investigated in vivo in randomly bred Swiss-Webster mice. Clearance of these substances from the circulation and tissue localization were determined at selected time intervals following the intravenous injection of 125I-labelled compounds. N- and ss-DNA were removed from the circulation more rapidly than was poly I : C. All three materials localized principally in reticuloendothelial-rich organs, i.e. liver and spleen. N-DNA was degraded by the liver more slowly than was poly I : C or ss-DNA. At 4 h following injection, the liver contained 26%, 13%, and 10% of the injected doses, respectively. Three days after injection, 4.5% of the N-DNA persisted in the liver, as compared to only 0.6% of the poly I : C, and 0.2% of the ss-DNA. The possiblity that these differences in metabolism of N-DNA, poly I: C, and ss-DNA may be related to their differing immunogenic potentials in experimental systems is discussed.

Animals↗
PubMed1978

Effect of pulse dose cyclophosphamide on the anamnestic immune response in NZB/W mice.

Mice exhibiting a spontaneous SLE-like lethal autoimmunity (female NZB/W hybrids) were given monthly doses of cyclophosphamide (CPA) 240 mg/kg p.o. starting at four months of age. Antibodies to DNA and sheep red blood cells (SRBC) were measured as well as general well being of the mice. The CPA-treated group demonstrated a marked increased in survival compared to the untreated controls with reduction of anti-DNA antibody levels but only a slight inhibition of the anamnestic response to SRBC immunization.

Animals↗
PubMed1977

Metabolism of exogenous single stranded DNA in normal and NZB/W mice.

Metabolism of ss-DNA in Swiss Webster mice and NZB/W mice was studied. The delay in intra-hepatic catabolism of ssDNA in old NZB/W female mice seems to correlate with the presence of increased anti-DNA antibodies; similar to effects produced in Swiss Webster mice that have been pretreated with a small dose of carbon black. Neither impairment in the phagocytic ability nor a decrease in DNase activity are found in the mice who are relatively unable to metabolize ssDNA. These observations are discussed in relation to possible pathogenesis in NZB/W mice.

Animals↗