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Biomedical subjects

P Aula

Publications and source records attributed to P Aula.

At least 91 records · Page 5Linked to original sources

Improved technique for the expression of fragile-X in cultured amniotic fluid cells.

An improved technique for inducing fra(X) expression in cultured cells was obtained by using diazepam for mitotic arrest and 5-fluorodeoxyuridine (FUdR) for the induction of fra(X) expression. The method was developed using cultured fibroblast and urinary cells from fra(X) patients. Prenatal studies were performed on cultured amniotic fluid cells in five pregnancies at risk for fra(X). In two cases the cultured cells showed a 46,XY, fra(X) karyotype. One of the pregnancies was terminated and the diagnosis was confirmed by chromosome studies on several fetal tissues including chorionic villi and by histopathologic changes in the lymphatic vessels of the fetal testes. The fra(X) was also demonstrated in chorionic villi in a case in which amniotic fluid cells were not studied. Chorionic villi were isolated after a spontaneous abortion, the cultured cells had a 45,X karyotype and in addition 5% of the cells were fra(X) positive.

Adult↗

Norrie disease caused by a gene deletion allowing carrier detection and prenatal diagnosis.

Carrier determination and prenatal diagnosis in Norrie disease (ND) has so far not been reported. We describe a kindred with 4 members affected by ND in which a deletion comprising gene locus DXS7 on the short arm of the X chromosome defined by probe L1.28 causes the disorder. This allowed us to predict via chorion villus biopsy that a male foetus of a carrier woman is unaffected.

Blindness↗

Risk of minor and major fetal malformations in diabetics with high haemoglobin A1c values in early pregnancy.

Maternal haemoglobin A1c (HbA1c) values were measured before the end of the 15th week of gestation in 142 pregnancies in women with insulin dependent diabetes. In pregnancies complicated by fetal malformations (n = 17) the mean initial HbA1c value was 9.5 (SD 1.8)% of the total haemoglobin concentration, which was significantly (p less than 0.001) higher than in pregnancies without malformations (8.0 (SD 1.4)%; n = 125). HbA1c values did not differ between pregnancies complicated by minor and major fetal malformations, but the rate of malformations showed a positive relation to the HbA1c value in early pregnancy (chi 2 = 11.9; p = 0.001). Fetal malformations occurred in six out of 17 pregnancies (35.3%) in mothers whose initial HbA1c value was 10% or more, in eight out of 62 pregnancies (12.9%) in mothers with initial values between 8.0% and 9.9%, and in only three out of 63 pregnancies (4.8%) in mothers with an initial value below 8.0%. These data support the hypothesis that the increased incidence of fetal malformations in mothers with insulin dependent diabetes is associated with maternal hyperglycaemia during organogenesis. Hence diabetic women who are planning to have a child--especially those with a high HbA1c value--should receive intensified metabolic control.

Adult↗

Prenatal diagnosis and fetal pathology of aspartylglucosaminuria.

The prenatal diagnosis of aspartylglucosaminuria (AGU), a lysosomal storage disorder of glycoprotein degradation, was made by demonstrating the deficiency of N-aspartylglucosaminidase on cultured cells from a midterm amniotic fluid sample. Four other amniotic fluid studies from at-risk pregnancies gave a normal or a heterozygote level of enzyme activity. These pregnancies have gone to term and the delivery of healthy babies. The pregnancy with the affected fetus was terminated and the prenatal diagnosis was verified by enzyme assays on cord blood lymphocytes, cultured cells from skin biopsy, and from placental villi. Electron microscopic evidence of lysosomal storage was seen in several organs of the fetus with the notable exception of the central nervous system. The undifferentiated mesenchymal fibroblasts particularly were heavily loaded with cytoplasmic inclusions in skin, liver, kidney, and placenta.

Acetylglucosamine↗

Identification of cells from fetal bladder epithelium in human amniotic fluid.

Cultured human amniotic fluid cells consist of five different types of cytokeratin-positive epithelial cells, E-1 to E-5, differing by their size, growth morphology, and cytokeratin pattern, according to our earlier investigations. Using anticytokeratin antibodies in indirect immunofluorescence (IIF) microscopy, we show in this study that cultured urine cells contain four of the cell types found in amniotic fluid. In addition, we used two urothelium-specific antibodies, anti-UMA and anti-Las-86, in combination with cytokeratin antibodies to distinguish urothelium-derived cells in amniotic fluid and urine cell cultures. Two of the epithelial cell types were found to express urothelial antigens and thus to originate from the transitional bladder epithelium. These cells were found in 26 of the 33 amniotic fluid cell cultures and in nine of the ten urine cell cultures.

Amniotic Fluid↗

Regional assignment of the structural gene for human alpha-L-iduronidase.

The structural gene encoding human alpha-L-iduronidase has been assigned to chromosome 22 by using immunologic, electrophoretic, and somatic cell hybridization techniques. Polyclonal rabbit antibodies raised against purified human low-uptake alpha-L-iduronidase were used to discriminate the human and murine isozymes by a sensitive immuno-precipitation assay. The human chromosome constitution of each clone was determined by cytogenetic and enzyme marker electrophoretic techniques. In 65 human (fibroblast)-mouse (RAG) somatic cell hybrids (from four independent fusions), the expression of human alpha-L-iduronidase was 100% concordant with the presence of human chromosome 22; the assignment was confirmed by the demonstration of the human enzyme in tertiary somatic cell hybrids containing only chromosome 22. Further verification of the gene assignment was made by detection of the human enzyme in tertiary chromosome 22 positive hybrids by Ouchterlony immunodiffusion and rocket immunoelectrophoretic experiments with polyclonal anti-human alpha-L-iduronidase antibodies that were monospecific for the human enzyme. Expression of human enzymatic activity in chromosome 22 positive hybrid lines was markedly reduced; for example, a tertiary hybrid (R-G21-J-15), which contained an average of 1.7 chromosome 22s per cell, only had about 15% of the activity detected in normal diploid fibroblasts. Immunologic studies suggested that the reduced expression was due to abnormal post-translational processing or aggregation (or both) of the human and murine isozymes in these hybrids. Regional assignment of the human structural gene to 22pter----q11 was accomplished by gene dosage studies using diploid human fibroblast lines that were partially monosomic or trisomic for chromosome 22.

Animals↗

Assignment of the structural gene encoding human aspartylglucosaminidase to the long arm of chromosome 4 (4q21----4qter).

The structural gene for the human lysosomal enzyme aspartylglucosaminidase (AGA) has been assigned to chromosome 4 using somatic cell hybridization techniques. The human monomeric enzyme was detected in Chinese hamster-human cell hybrids by a thermal denaturation assay that selectively inactivated the Chinese hamster isozyme, while the thermostable human enzyme retained activity. Twenty informative hybrid clones, derived from seven independent fusions, were analyzed for the presence of human AGA activity and their human chromosomal constitutions. Without exception, the presence of human AGA in these hybrids was correlated with the presence of human chromosome 4. All other human chromosomes were excluded by discordant segregation of the human enzyme and other chromosomes. Two hybrid clones, with interspecific Chinese hamster-human chromosome translocations involving the long arm of human chromosome 4, permitted the assignment of human AGA to the region 4q21----4qter.

Amidohydrolases↗

Purification and properties of human hepatic aspartylglucosaminidase.

Aspartylglucosaminidase (EC 3.5.1.26), the lysosomal enzyme which hydrolyzes the N-acetylglucosamine-asparagine linkages in glycoproteins, was purified from human liver to homogeneity. The purification procedure included chromatography on DEAE-cellulose and concanavalin A-Sepharose, gel filtration on Sephadex G-200, and high performance liquid chromatography. The purified enzyme had a final specific activity of 1,200,000 units/mg of protein, a pH optimum of 6.1, a pI of 5.7, a Vmax of 1,240,000 units/mg, and a Km of 1.25 mM toward a natural substrate, aspartylglucosamine. The purified enzyme was remarkably thermostable, retaining 90% of initial activity after 1 h at 60 degrees C. The molecular weight of the native enzyme was estimated to be 80,000 by gel filtration and 84,000 by analytical polyacrylamide gel electrophoresis. Under denaturing conditions, the molecular weight was 76,000, indicating that the native enzyme was a monomer. Amino acid composition revealed only 2 methionine residues/enzyme molecule.

Adult↗

Alkaline phosphatase activity in amniotic fluid in pregnancies with fetal disorders.

Alkaline phosphatase (ALP) activity was determined in 255 amniotic fluid samples collected by amniocentesis between 15 and 39 weeks of gestation. The samples were originally used for chromosomal analysis and/or alpha-fetoprotein measurements. The mean ALP activity in early amniotic fluid from pregnancies with fetal trisomy 18 and 21 syndromes was half of that found in the controls. Highly elevated ALP activity (over 10 times the median level) was found in 14 samples. Two of these pregnancies had normal outcome. Three samples were from pregnancies with intrauterine fetal death. Fetal disorders, including abdominal wall defect (four cases), Meckel's syndrome (two), hydrops fetalis syndrome (two) and genital anomaly (one), were observed in nine cases. Moderately elevated ALP activity (over three times the median) was found in 10 cases, including five pregnancies with a preterm labour shortly after the sample collection. The results indicate that elevated ALP activity in the third trimester amniotic fluid is often associated with fetal disorders.

Alkaline Phosphatase↗

Antenatal screening for congenital nephrosis in Finland by maternal serum alpha-fetoprotein.

In the Kuopio and North-Karelia districts of Finland 10724 pregnancies were screened for congenital nephrosis by maternal serum alpha-fetoprotein (AFP) measurement. Outcome was known for 10504 (98%) pregnancies, of which 509 (4 X 8%) had a serum AFP level greater than or equal to 2 X 5 multiples of the normal median (MoM) at 15-18 weeks gestation. After exclusion of those women who had a normal serum AFP level (less than 2 X 5 MoM) in a second sample, 'wrong dates' or multiple pregnancy, 267 (2 X 5%) remained with a high serum AFP level. Amniocentesis was carried out in 225 (2 X 1%) and 16 women had an amniotic fluid AFP level greater than 10 SD above the normal mean. In this group there were six fetuses with congenital nephrosis (four confirmed and two suspected), six other serious malformations (including an intrauterine death) and four without obvious abnormality. In the 98% pregnancies followed up there were no infants with congenital nephrosis that had been missed. Babies with congenital nephrosis require permanent hospitalization and have a mean survival of 8 months. In Finland, within certain areas, the birth prevalence is as high as 1 in 2600 per year. In such areas maternal serum AFP measurement appears to be a useful method of screening for congenital nephrosis. The service was also well accepted since 94% of the women with raised serum AFP levels wished to be screened again in a future pregnancy.

Amniocentesis↗

Salla disease: a new lysosomal storage disorder with disturbed sialic acid metabolism.

Salla disease is a lysosomal storage disorder associated with increased urinary excretion of free sialic acid. The main clinical features in 34 patients were severe psychomotor retardation of early onset, ataxia, athetosis, rigidity, spasticity, and impaired speech. Growth retardation, thick calvarium, and exotropia were present in about half the patients. The amplitude of EEG decreased progressively with increasing age. Life span appears to be normal; the age range of the patients was 3 to 63 years. Genealogic studies suggest an autosomal mode of inheritance. A thin-layer method is described for the detection of increased urinary free sialic acid excretion. The basic defect is so far unknown.

Adolescent↗

Decrease in gamma-glutamyl transpeptidase activity in early amniotic fluid in fetal trisomy 18 syndrome.

A study was carried out in which activity of gamma-glutamyl transpeptidase was measured in 259 samples of amniotic fluid obtained at various weeks of pregnancy. Two hundred and twenty-eight of the babies subsequently delivered had no chromosome abnormality and served as controls, while in 31 various chromosome abnormalities were detected. Mean activity of gamma-glutamyl transpeptidase in the control samples at 15 weeks was 602 U/l. Activity in the samples obtained in cases of fetal chromosome abnormality was generally below this: it was below the 10th percentile in 74% of the samples and below the 2.5th percentile in 52% of the cases. It is concluded that assay of gamma-glutamyl transpeptidase activity is a rapid preliminary test for prenatal diagnosis of chromosomal abnormalities.

Amniotic Fluid↗

Heart rate patterns in trisomic fetuses.

A survey of the clinical records of fifteen fetuses with trisomy 21, six fetuses with trisomy 18, and two fetuses with trisomy 13 was made in order to find out typical patterns of fetal heart rate (FHR) possibly associated with these conditions. Antepartal FHR patterns of 55 normal pregnancies and intrapartal FHR patterns of 14 normal labors were used as a control material. Trisomic fetuses showed significantly fewer FHR accelerations than did the controls. Fetuses with trisomy 18 and 13 had more antepartal decelerations than fetuses with trisomy 21. Trisomic fetuses also showed more intrapartal late decelerations and epochs of silent FHR pattern than did the controls. The abnormal FHR patterns of the trisomic fetuses thus were similar to those in placental insufficiency. Cesarean section was performed for both fetuses with trisomy 13, for five of the six fetuses with trisomy 18 and for nine of fifteen fetuses with trisomy 21. In eleven of sixteen cesarean sections the main indication was abnormal cardiotocogram. Fetal karyotyping from an amniotic fluid sample should perhaps be considered when decelerations and silent patterns of FHR in a growth-retarded, late second or early third trimester fetus are seen. In most cases, however, the decision for optimal management o labor must be based on FHR patterns solely.

Chromosomes, Human, 13-15↗