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Biomedical subjects

A Daniel

Publications and source records attributed to A Daniel.

At least 91 records · Page 5Linked to original sources
PubMed1983

Red cell creatine in term and preterm, adequate and small for gestational age newborns after normal pregnancy or risk conditions. II. Mathematical analysis of 12 risk conditions in relation to the creatine level at birth.

Univariate and multivariate analysis of variance and discriminant analysis were performed on newborns with respect to the level of red cell creatine at birth (cord blood) and 12 risk conditions occurring during the last trimester of gestation and birth. 111 of the 174 newborns studied had been at risk. The factor "small for gestational age" (SGA) showed to have a negative coefficient of discriminant function, i.e. it contributes to lower creatine values at birth. Other risks are shown to raise the creatine level. For "adequate for gestational age" (AGA) newborns "Rh-incompatibility", "toxoplasmosis", "premature and/or prolonged rupture of the membranes", "complications of the umbilical cord" and - to a minor degree - "pyelonephritis of the mother", "threatened premature labour", and "toxemia of pregnancy" were shown to be significant risks leading towards high red cell creatine concentrations in cord blood. For the SGA infants "preterm birth", "threatened premature labour", "green amniotic fluid" and "toxemia of pregnancy" were the most important risks relating to high creatine levels of red cells at birth.

Analysis of Variance↗
PubMed1983

Red cell creatine in steady state and stimulated erythropoiesis.

Intra- and interindividual variances as well es the age dependency of red cell creatine were studied. Following a single erythropoietic stimulation creatine can stay elevated for many months. A rise of creatine may not only reflect a shift towards a younger cell population but also different erythropoietic sites. The creatine concentration of red blood cells (rbc) has been shown to be an excellent indicator of cell age (1,2,3) and of dynamics of erythropoiesis (3). Intra- and interindividual variances were determined. Fig. 1 (designed according to 4) shows the variance of the method (3)-both for serial determinations and for repeated analyses of the same sample after storing up to 19 days--as well as the variances for the individual person and for a group. It is shown, that the values for one individual are remarkably constant. Fig. 2 illustrates values obtained from presumably healthy persons without evidence of hematological pathology--from newborn to old age. The fat bar represents the values for adults with a mean of 6,64 mg/dl cells and a rather small standard deviation. The mean creatine concentration for very old persons (bar to the utmost right) appears to be higher with a larger standard deviation. However, these values probably should be taken with caution, since some of the persons might have had some minor cardiac or pulmonary difficulty or occult blood loss from the gastrointestinal tract--even though they were declared healthy by the physician of the seniority home. From the age of 6 months on there appears to be no age dependency of rbc creatine concentration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1983

Dipalmitoylphosphatidylcholine in amniotic fluid quantified by fast-atom-bombardment mass spectrometry.

Dipalmitoylphosphatidylcholine (DPC) is quantified by taking advantage of stable-isotope-labeled d9-DPC as internal standard. Use of a mass spectrometer to measure the ratio of d9/d0 makes this procedure a quantitative one. d9-DPC was synthesized by refluxing dipalmitoylethanolamine with d3-methyl iodide in methanol in the presence of sodium bicarbonate for 26 h. The yield of d9-phosphatidylcholine (d9-lecithin) was 89% after column-chromatographic purification. Fast atom bombardment was used to desorb the preformed phosphatidylcholine ions in a mass spectrometer of Nier-Johnson geometry. In our assessment of accuracy and precision of this technique, we found a correlation coefficient of 0.9994 between signal and sample concentration. The method was less precise when the total d0- plus d9-DPC was less than 0.2 micrograms or when the ratio of d0- to d9-lecithin exceeded 100. The within-run CV was about 1.0%. The amount of DPC in amniotic fluid samples assessed by mass spectrometry was compared with results for total phosphatidylcholine quantified by thin-layer chromatography. The fate of DPC in various laboratory manipulations was also studied.

Amniotic Fluid↗
PubMed1983

Effect of urinary proteins on in vitro immunological tests for pregnancy.

A study of the possible interference of urinary proteins with all the commercial in vitro pregnancy products on the market in the United States today was carried out by our group. Six of these tests were of the tube type and seven were slide tests. Radioimmunoassays and receptor assays for beta human chorionic gonadotropin (beta-HCG) were not tested. The products examined showed interferences by urinary proteins presented at various levels. Interference by human serum albumin (HSA) (in five tube tests) occurred only at a physiologically improbable, high concentration of HSA (5 g/dL). However, in certain cases interferences by serum proteins (false positive type) occurred at concentrations lower than 0.06 g/dL which are physiologically probable. The four tests formulated to work with both serum and urine did not show any urinary protein interference with HCG measurements. There was no clear difference in urinary protein interferences between the tube and the slide tests; the tube tests were slightly more sensitive to the presence of HSA. Those tests employing latex beads, as opposed to erythrocytes, showed greater sensitivity to protein interferences.

Blood Proteins↗
PubMed1982

Prenatal diagnosis in 3,000 women for chromosome, X-linked, and metabolic disorders.

In 3,000 women referred for prenatal diagnosis, 110(3.7%) abnormal fetuses were detected and 85 therapeutic terminations were performed. These were five main reasons for referral. Among the 2,227 women referred because of maternal age 35 years and older, there were 51 (2.3%) who had aneuploid fetuses. In the 297 women referred because of a previous child with Down syndrome, 3 aneuploid fetuses (1.0%) were detected. Of the 55 couples where one spouse was a carrier of a balanced chromosome rearrangement, 6 chromosomally abnormal fetuses were found (10.9%) (all the offspring of maternal carriers). In the latter group, five of the six heterozygotes with abnormal findings were carriers of tdic (13;21) translocations. In the 82 cases with a history of X-linked disorders, there were 40 males (49%). Thirty-five women were referred because of inborn errors of metabolism: 10 affected fetuses were found (28%). There was a greater proportion of sex-chromosome aneuploids as compared to trisomy 21 fetuses in the 35 to 39 year maternal age group. This was reversed in the group of women 40 years old and older. Of the 25 abnormal fetuses not terminated, 6 were sex chromosome aneuploids and 10 involved X-linked conditions where the progeny could be further prenatally monitored (eg, X-linked hydrocephalus) or treated (eg, hemophilia). In the remaining 9 the parents expressed divers reasons for their choice. Repeat amniocentesis was required in 2.9% of cases. One case of maternal cell contamination and one case of unconfirmed mosaicism were the only diagnostic errors found in the study. In the last 1,000 specimens referred, the average time necessary for a karyotypic result was 15.6 +/- 5.6 days after amniocentesis.

Abortion, Induced↗
PubMed1982

The fragile X(q27) form of X-linked mental retardation: FUdR as an inducing agent for fra(X)(q27) expression in lymphocytes, fibroblasts, and amniocytes.

The effect of FUdR on the expression of fra(X)(q27) was examined in lymphocytes and/or fibroblasts from 16 affected males and 5 carriers from 10 families; six different culture media were used: F10, 5% serum, pH 7.3(37 degrees C); medium 199, 5% serum, pH 7.6(37 degrees C); folate-free 199, 5% serum, pH 7.6(37 degrees C), and these three media with FUdR (0.05 micron). In lymphocytes there was no significant difference in the percentage of fra(X) expressing cells between any of the FUdR-containing media. The highest percentage of expressing cells seen in lymphocytes with FUdR was 56%. The average enhancement in males with FUdR in the 199 and folate-free 199 media was 30%. This relative enhancement with FUdR was very much higher in a few blood specimens delayed in transit and FUdR may prevent some of the false-negative results obtained from mailed specimens. FUdR did not induce the marker in four obligate carriers with previously negative results. The fibroblasts from affected males were grown in the six specific media for the last 48 hr. Two of the six media yielded reproducibly positive results. These were 199-FUdR and folate-free 199-FUdR with mean percentages of expressing cells of 12.8 +/- 7.1% and 11.3 +/- 6.1%, respectively. F10-FUdR, which contains thymidine, did not permit expression of the marker in fibroblasts and there was no difference in the percentage of fra(X) expression in 199-FUdR media with or without folate. It was concluded that FUdR shows promise as an agent to permit prenatal diagnosis of the condition and to enhance the detection of the marker in lymphocyte cultures.

Cells, Cultured↗
PubMed1982

[Erythrocyte creatine concentration in infants and children with congenital heart disease and left-to-right shunts (author's transl)].

The creatine concentration of red blood cells was determined in 58 children with congenital acyanotic malformations of the heart at the age of 3 weeks to 3 1/2 years. It was correlated to the severity of the hemodynamic changes, the physical development of the children and number of reticulocytes. The average creatine concentration in the red cells of all patients was 12.8 +/- 4.80 mg/100 ml cells, i.e. twice as high as that of the control group (6.61 +/- 1.19 mg/100 ml cells). Particularly high creatine values were found in children, who died in consequence of their heart disease without previous operation (18.49 +/- 4.25 mg/100 ml cells, n = 11) and those children who had to be operated on as a life-saving measure (17.88 +/- 3.43 mg/100 ml cells, n = 10). The highest creatine concentration was found in a 4 weeks-old infant with hypoplastic left heart syndrome (25.3 mg/100 ml cells). In children with a systolic pressure in the pulmonary artery of greater than 50 torr the creatine concentration was significantly higher than in those with pressures less than 50 torr. Increased creatine values correlated well with the poor physical development and increased reticulocyte numbers of the children. There was no correlation found between capillary pO2 and creatine concentration. It is concluded that the determination of erythrocyte creatine in children with congenital heart disease of the left-right shunt type furnishes additional objective information on the general condition of the organism and its adaptation capacities to hypoxia. It may serve as a valuable diagnostic and prognostic measure.

Blood Cell Count↗
PubMed1981

Growth induction in cystic fibrosis fibroblasts with low dexamethasone concentrations. Experience with application to genotyping.

Dexamethasone (DM) resistance was evaluated in fibroblasts from a pool of five patients with cystic fibrosis (CF) homozygotes, ten of their parental obligate heterozygotes, and seventeen age-matched controls of both sexes. The CF heterozygotes showed a mean DM resistance greater than homozygotes and both groups exhibited a higher mean DM resistance at every DM concentration than controls. However, substantial interassay variability rendered these differences in the total pooled data to non-significance. One control showed a consistently increased resistance and was possibly a covert heterozygote. It was concluded that the phenomenon of DM resistance was exhibited by CF heterozygotes and homozygotes but was not discrete enough for genotyping in the prenatal diagnosis of CF.

Cell Division↗
PubMed1981

Structural differences in pericentric inversions. Application to a model of risk of recombinants.

The potential chromosomal imbalance in offspring of pericentric inversion heterozygotes can be evaluated by measuring (% of haploid autosomal length, % HAL) the chromosomal segments distal to the breakpoints in the inversion. These distal segments were measured in presently reported and published cases of pericentric inversions, divided into two ascertainment groups: (I) those ascertained through recombinant offspring and (II) those ascertained through balanced heterozygotes. The distal segments in group II inversions were significantly larger than those of group I, i.e., the potentially larger chromosomal imbalances were not observed in full-term offspring. These results are discussed in relation to the model of risk of abnormal offspring in the progeny of heterozygotes for structural rearrangements (the chromosome imbalance size--viability model). The mean distal segment sizes for group I and group II pericentric inversions were respectively not significantly different from the mean interchange segment size for a sample of reciprocal translocations divided into the same two ascertainment groups. It was concluded that the restrictions on the size (% HAL) of chromosomal imbalance in offspring surviving until term are similar whether this imbalance arises from reciprocal translocations or pericentric inversions.

Chromosome Aberrations↗
PubMed1981

Quantitative nephelometric determination of Haemophilus influenzae antigen in body fluids.

Nephelometry, an immunological technique widely used for the quantification of blood proteins, was adapted to provide a quantitative method of detecting Haemophilus influenzae capsular antigen in body fluids. Using specific antiserum directed against H. influenzae capsular antigen, samples of serum, cerebrospinal fluid, urine, and joint fluid from 38 cases of H. influenzae infections were analyzed. The results were compared for reliability to counterimmunoelectrophoresis, a widely used diagnostic tool. The nephelometric technique has the same advantages of speed and specificity as counterimmunoelectrophoresis and provides the clinician and researcher with a quantitative method that is as reliable as the qualitative counterimmunoelectrophoresis procedure. The method allowed directly quantitative readouts on patient specimens, with no necessity for serial dilutions or densitometric readings.

Antigens, Bacterial↗
PubMed1981

Prenatal diagnosis for adenosine deaminase deficiency.

Amniocentesis was performed in two successive pregnancies of the mother of a child with adenosine deaminase (ADA) deficient severe combined immunodeficiency. Assay of ADA in amniotic fluid fibroblasts showed the pregnancies to be normal and homozygous deficient, respectively. These findings were confirmed by the demonstration of a normal level of erythrocyte ADA in the cord blood of the healthy male born of the first pregnancy and by the demonstration of undetectable ADA activity in cord erythrocytes, spleen, liver, and kidney of the abortus of the second pregnancy. Prenatal diagnosis of ADA deficiency appears to be a reliable procedure.

Adenosine Deaminase↗
PubMed1981

Creatine in density-fractionated red cells, a useful indicator of erythropoietic dynamics and of hypoxia past and present.

Creatine in density-fractionated red cells is not only a useful criterion of cell age but also an excellent indicator of erythropoietic dynamics particularly under the influence of present and past hypoxia. This is documented on patients with cardiac hypoxia. A histogram is proposed which permits the simultaneous evaluation of four parameters: (1) the creatine concentration of each separate fraction, (2) the absolute density of a given cell fraction, (3) the percentage distribution of cells over the whole gradient and within the different fractions and (4) the general position of the red cell population with respect to its median density, which serves to characterize the overall age of a red cell population. Creatine histograms on fractionated red cells are shown to be useful aids for diagnosis and prognosis in hypoxic clinical states. They may also give retrograde information on past stimulation of erythropoiesis.

Adult↗
PubMed1980

Heterozygous expression of X-linked mental retardation and X-chromosome marker fra(X)(q27).

Males affected by one form of X-linked retardation possess the X-chromosomal marker fra(X)(q27) and are physically normal except for macro-orchidism. To relate possession of the marker X to phenotypic expression in female heterozygotes, we investigated 128 mildly retarded (IQ, 55 to 75) school-girls in Sydney, New South Wales, Australia. Seventy-two girls had no physical abnormalities and of these, five (7 per cent) carried the marker X. Investigation of relatives revealed retarded males in four of the five families. Pedigree and chromosomal analysis identified a further 18 heterozygotes; six were regarded as intellectually or educationally retarded. We conclude that expression of the X-linked mutation in female carriers contributes to mild mental retardation of girls, that those who are physically normal should be screened for the marker X, and that their relatives should be investigated in order to identify additional females with a high risk of conceiving affected males.

Child↗
PubMed1980

Two dicentric Y isochromosomes, one without and the Yqh heterochromatic segment: review of the Y isochromosomes.

Two women with primary amenorrhoea and few other stigmata of Turner's syndrome were found to be chromosome mosaics: 45,X/46,X,idic(Y). In Case 1, the dicentric isochromosome Y was found to have a long-arm breakpoint of formation. This structure was interpreted as containing two Y short arms and centromeres separated by a region derived from the proximal Y long arm. One of the centromeres in the Case 1--idic(Y) was suppressed in 80% of cells in blood, and in these cells it appeared as a regular Y-shaped chromosome. In Case 2 the idic(Y) was derived by a short-arm breakpoint of formation. In all the dicentrics of this case with one primary constriction (functional monocentrics) there was a single Cd band. In the 10% of dicentrics with two primary constrictions, there were two Cd bands. It is argued that the instability of sex isochromosomes is due to this functional dicentricity in some cells. These cases are compared with 42 other Y isochromosomes with various short- and long-arm breakpoints of formation. It is suggested that some of the nonheterochromatic, nonfluorescent Y chromosomes previously reported may be explained as dicentric i(Y) with proximal long-arm breakpoints of formation and one suppressed centromere.

Adolescent↗
PubMed1980

X-linked mental retardation, macro-orchidism, and the Xq27 fragile site.

Twenty-three families with X-linked mental retardation were examined for the presence of a fragil site on the long arm of the X chromosome (Xq27 fra). Specific culture media were necessary to demonstrate this site. In only seven of the families was the Xq fragile site observed; in these, all of the affected males had both the fragile X and macro-orchidism. Macro-orchidism was not observed in the remaining 16 families. In the families with Xq27 fra segregating the fraes. This correlated with the age of the carrier. The 25 affected males with macro-orchidism and Xq27 fra had some minor clinical features in common: there was an increase in birth weight, high forehead, prognathism, pale irides, big ears, and an increased head circumference in infancy and childhood which did not persist into adult life. The majority of the affected individuals were moderately retarded.

Abnormalities, Multiple↗