Biomedical subjects
Publications and source records attributed to C C Lin.
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On the basis of analyses of the nonstressed fetal heart rate test (NST) and the oxytocin challenge test (OCT) in 85 fetuses with intrauterine growth retardation (IUGR), the predictive power of NST/OCT on fetal outcome and the mechanism of a positive OCT in IUGR were investigated. These fetuses with IUGR exhibited high incidences of nonreactive NSTs (35.3%) and positive OCTs (40%) attributable to a combination of compromised placental function and diminished fetal reserve. Adverse fetal prognosis is most accurately predicted by the joint occurrence of a nonreactive NST and a positive OCT (92%). In such cases, when IUGR is strongly suspected, liberal use of cesarean section is recommended to assure good fetal outcome.
Amniotic fluid C-peptide (AFCP) was monitored as an indicator of the amount of insulin secreted by the fetus in utero. Levels of amniotic fluid and cord blood C-peptide, insulin, and glucose were measured in 103 nondiabetic infants at greater than or equal to 36 weeks's gestation. Infants were grouped according to birth weight and gestational age at delivery, as follows: small gestational age (SGA, less than or equal to 10%, n = 11), average for gestational age (AGA, 10% to 90%, n = 75), large for gestational age (LGA, greater than 90%, n = 17). AFCP correlated best with infant weight-gestational age percentile classification: low AFCP in SGA infants and high AFCP in LGA infants. The data from this study suggest that a persistently low production of insulin by SGA fetuses and a high production of insulin by LGA fetuses may lead to the different intrauterine growth rates observed.
Bright-field microscopy of silver-stained pachytene spermatocytes of a male Indian muntjac, Muntiacus muntjak revealed that (a) the synapsis between the autosomal homologs, including the long arm of the X and Y2, was normal, (b) the nucleolus organizer regions were present in both the No. 1 bivalent and the long arm of the X and Y2, (c) the accessory structures of the X chromosome short arm in the forms of light and dark thickenings and the hairpin-like bend were present despite the X-autosome translocation, (d) a short synaptonemal complex was present between the Y1 (real Y) and the short arm of the X chromosome, and (e) the centromeric orientation of the Y1 and Y2 chromosomes was in Cis configuration as opposed to the X chromosome.
Immune responses to several soluble antigens were compared between B6.C-H-2bm12 mutant and wild-type B6 mice by using a lymph node T-cell proliferation assay. B6.C-H-2bm12 mice failed to respond to beef insulin whereas other IA gene-controlled responses, such as response to poly(L-Tyr, L-Glu)--poly(DL-Ala, L-Lys) and collagen, were indistinguishable between mutant and wild-type mice. The responses to multideterminant antigens such as ovalbumin and purified protein derivative of tuberculin were also found to be comparable in B6.C-H-2bm12 and B6 mice, thus indicating that this mutation resulted in a selective loss of the ability to respond to a certain antigen(s)--e.g., beef insulin. Populations depleted of adherent cells have been used to examine the mechanism by which Ia molecules mediate Ir gene control of antigen recognition. We show that the nonresponsiveness to beef insulin in the mutant mouse is the result of defective antigen presentation. In addition, we find that F1 hybrids between two nonresponders--B6.C-H-2bm12 and B10.A or B10.AKM (IAk) mice--become responders to beef insulin, thus demonstrating gene complementation. These findings taken together with other serologic and biochemical studies in the B6.C-H-2bm12 present convincing genetic evidence for the direct association of the A beta polypeptide chain of the Iab molecules with the expression of immune responsiveness to beef insulin. Study of the B6.C-H-2bm12 mouse should provide new insight into the cellular and molecular mechanisms by which Ir genes determine the nature of the immune response.
A fluorescent compound, DEAP fluoranthene (a tilorone cogener), has been suggested to bind to DNA by intercalation. The interaction of this drug with natural and synthetic DNAs and human metaphase chromosomes has been investigated in detail. DEAP fluoranthene shows a slight A-T preference in binding to DNA and was also found to change the topological winding number of superhelical DNA. These data, and the determined unwinding angle of 27 degree for DEAP fluoranthene, strongly support an intercalation mode of binding for this drug to DNA. DEAP fluorescence is minimally quenched when intercalated between A-T base pairs and maximally quenched when interacting with G-C base pairs. DEAP fluoranthene was found to produce bright fluorescent bands on human metaphase chromosomes identical to those produced by quinacrine. The solution data on DEAP fluoranthene interaction with DNA can be used to rationalize the production of differential banding patterns on chromosomes by DEAP fluoranthene in which the drug reports underlying DNA sequence arrangement of the metaphase chromosome.
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Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Phosphoenolpyruvate carboxylkinase (GTP:oxaloacetate carboxy-lyase (transphosphorylating), EC 4.1.1.32) is inactivated by bromopyruvate with specific substrate protection against the inactivation. Despite the fact that the enzyme also is known to possess oxalacetate decarboxylase activity, the modification does not appear to be directed toward a pyruvate or enolpyruvate binding site, as evident from the kinetics of the inactivation and from protection studies. Thus, the reactivity of bromopyruvate is different than toward several other enzymes where pyruvate is a substrate or product. Acetopyruvate and oxalate inhibit carboxykinase activity, but neither of these compounds, nor pyruvate, protects against the inactivation. Using differentially labeled enzyme, it was shown that modification of one sulfhydryl is sufficient to cause loss of both catalytic activities. Protection by inosine nucleotides was found to be similar in each instance. It would appear that a common sulfhydryl is critical to both carboxykinase and oxalacetate decarboxylase activities, and that each utilizes the same nucleotide binding site, despite the known different roles of the nucleotide in each reaction.
The maternal and fetal cord blood from 37 infants with intrauterine growth retardation (IUGR) and 108 normal growth (AGA) infants were compared for lactate, pH, and blood gas values in an attempt to find whether there is any difference in stressed response in IUGR fetuses during labor and delivery. Both maternal and fetal blood lactate levels increased with progression of labor, fetal lactate being higher than the maternal lactate. Without intrapartum fetal heart rate decelerations, IUGR fetuses did not show a difference in umbilical arterial lactate, pH, and blood gases, compared to AGA fetuses. With intrapartum fetal heart rate decelerations, IUGR fetuses demonstrated a significantly higher lactate level than that of AGA fetuses. We conclude that IUGR fetuses tolerate labor less well than do AGA fetuses. In the presence of late decelerations, earlier intervention is preferable because of the increased likelihood of metabolic acidosis.
1-Anilinonaphthalene-8-sulfonate (ANS) binds to phosphoenolpyruvate carboxykinase with subsequent rapid inactivation. Kinetics are saturating, with an enzyme half-life of 0.29 min at 4 x 10(-4) M ANS. IDP, GDP, and phosphoenolpyruvate protect against the inactivation. The enzyme is not covalently modified and it retains an affinity for protecting substrates and substrate analogs, with the exception of oxalate. Binding of ANS occurs in a hydrophobic environment, as suggested by the changes in fluorescence emission, and is markedly pH-dependent, leading to more rapid inactivation at acid pH. Inactivation by ANS differs in this respect from inactivation by N-(iodoacetylaminoethyl)-5-naphthylamine-1-sulfonate which affinity labels the enzyme (Silverstein, R., Rawitch, A.B., and Grainger, D.A. (1979) Biochem. Biophys. Res Commun. 87, 911-918). Though the mechanism by which ANS inactivates the enzyme is unclear, the effect is atypical in that ANS binding does not normally lead to irreversible inactivation.
The family of 2 men with X-linked mental retardation was investigated for the presence of the marker-X chromosome and macro-orchidism. Lymphocyte cultures were set up in media F-10 and 199. Chromosomes were G-band-stained and slides coded for blind analysis. Marker-X chromosomes and autosomal gaps were seen only in cultures prepared with medium 199. Autosomal gaps were seen in all family members and controls. The marker-X chromosome was present inaffected male (3% and 15.5%) and female family members (0.5%-6.5%) but not in controls or a normal male family member. Bilateral macro-orchidism was present in 1 affected male and unilateral macro-orchidism in the other. Both had normal penile measurement. The replication pattern of the marker-X chromosome was studied in 1 woman by BrdU labelling. BrdU decreases the frequency of marker-X expression. As the marker-X chromosome was the late-replicating X in 9/20 cells, it appears that there is no preferential inactivation of the marker-X in this woman.
We describe a case of tertiary trisomy (22q11q) 47,XX,+der(22),(22pter = to 22q13 :: 11q25 = to 11qter) in a child with mental retardation, cleft palate, and congenital heart disease resulting from 3 : 1 meiotic nondisjunction in a maternal (11;22) translocation carrier. The clinical findings in previously reported cases are reviewed and compared with the features of reported patients with "partial trisomy 11q" and "trisomy 22" syndromes. Half of the ten reported families had additional balanced translocation carriers who may have an increased risk of having a liveborn child with an MCA/MR syndrome, although none have been reported to date.
Metaphase chromosomes stained with acridine orange exhibit uniform yellow-green fluorescence. Chromosome preparations treated with the non-fluorescent A-T specific antibiotic distamycinA prior to acridine orange staining exhibit longitudinal fluorescent banding patterns similar to those produced by a number of fluorescent R-band techniques. Similarly, chromosome preparations treated with the non-fluorescent G-C specific antibiotic actinomycin D followed by acridine orange staining exhibit "Hoechst-type" banding patterns. Interactions of various ligand-DNA combinations in solution indicate that the base pair specific antibiotics induce banding patterns by selectively altering acridine orange binding sites in chromosomal regions rich in the particular base pair for which the antibiotic exhibits specificity.
A case is described of selective immunoglobulin A deficiency in association with an 18q+ anomaly, apparently the result of a break at 18q23 and a de novo translocation. The presentation is compared with the phenotypic and immunological features in an IgA deficient 18q-- patient. The findings in these two patients suggest that gene(s) concerned with regulation of IgA synthesis are located on the distal long arm of chromosome 18 between 18q23 and qter.
Various banding techniques have been used for chromosome analysis in domestic pigs (Sus scrofa domestica). The techniques used in karyotype analysis were Q-banding by (CMA)2S, trypsin-G-banding, BrdU-Acridine-Orange R-Banding and C-banding. Sequential staining techniques of quinacrine-Giemsa were used to record the length of each chromosome and determine arm ratios. Sequential Quinacrine-Giemsa-Ag-AS treatment was used to locate the nucleolar organizer (NOR) on specific chromosomes. A G-C specific fluorochrome was used for reverse fluorescent banding and to differentiate certain chromosome regions which may contain G + C rich DNA. Unequivocal identification of all individual autosomes and sex-chromosomes in the porcine complement is now possible. The X-chromosome of the species has a banding pattern similar to the human X-chromosome. A nomenclature system similar to that used for human chromosomes is proposed for the G-banded and Q-banded karyotype of the domestic pig. The results of C-banding and olivomycin fluorescent banding suggest that at least three types of heterochromatin are contained in the porcine genome.