Spectrum of phenylketonuria mutations in Western Europe and North Africa,and their relation to polymorphic DNA haplotypes at the phenylalanine hydroxylase locus

Summary A total of 252 chromosomes from 126 patients with phenylalanine hydroxylase (PAH) deficiencies were analyzed for both mutant genotypes and restriction fragment length polymorphism (RFLP) haplotypes at the PAH locus. The mutant genes studied originated either from Western Europe (116 alleles) or from Mediterranean countries (136 alleles). Only 27% of all mutant alleles were found to carry identified mutations, particularly mutations at codon 252 (2.3%), 261 (7.5%), 280 (6.3%), 408 (3.5%) and at the splice donor site of intron 12 (6.3%). The mutant genotypes were associated with RFLP haplotypes 7, 1, 38, 2 and 3 at the PAH locus respectively. Except for the splice mutation of intron 12, these associations were preferential, but not exclusive, since the other four mutations were found on the background of at least two RFLP haplotypes. These results, together with the observation that 85% of PAH deficient patients are heterozygotes for their mutant genotypes, emphasize the great heterogeneity of PAH deficiencies in Mediterranean countries and hamper systematic DNA testing for carrier status in this population.     

Alpha-fetoprotein and trisomy 21

In 31 affected pregnancies with Down syndrome, the median maternal serum alpha-fetoprotein value was lower than normal, 0.76 MoM, and median amniotic fluid value was quite normal, 0.98 MoM. Selecting an arbitrary cutoff-point of 0.5 MoM, 4.1 percent of normal gestations show values less than 0.5 MoM. Authors discuss problems about screening for fetal Down's syndrome by measuring maternal serum AFP levels.     

Contribution of amniocentesis to prenatal screening of neural tube closing defects: evaluation of 10 years of a center's experience

The authors report retrospective data on analysis of amniotic fluid DFTN markers (AFP and AChE) from 306 cases. Data were obtained from 261 amniocentesis done because there was a recurrence risk of DFTN and from 45 amniocentesis done because an anomaly as DFTN was diagnosed with ultrasonography. Results first show that the risk of recurrence is 3.03% in Rh?ne-Alpes area. In utero exposure to valproate appears as new indication for amniocentesis, in view of the possible association between Spina-Bifida and prenatal-valproate exposure (1/8 in the study). In contrast to anencephaly, Spina Bifida can be difficult to diagnose with ultrasonography before 20 weeks and require amniocentesis with AFP and AChE study.     

Ultrasonography and alpha fetoprotein determination: two complementary tests in the prenatal diagnosis of anencephaly

From an observation, authors underline the interest of two complementary tests: ultrasonography and amniotic fluid AFP determination. About the reported case, the chronology of facts is unusual: ultrasonography led initially to suspect anomaly, then elevated AFP result confirmed the malformation.     

Extraction of extracellular polymeric substances (EPS) from anaerobic granular sludges: comparison of chemical and physical extraction protocols

The characteristics of the extracellular polymeric substances (EPS) extracted with nine different extraction protocols from four different types of anaerobic granular sludge were studied. The efficiency of four physical (sonication, heating, cationic exchange resin (CER), and CER associated with sonication) and four chemical (ethylenediaminetetraacetic acid, ethanol, formaldehyde combined with heating, or NaOH) EPS extraction methods was compared to a control extraction protocols (i.e., centrifugation). The nucleic acid content and the protein/polysaccharide ratio of the EPS extracted show that the extraction does not induce abnormal cellular lysis. Chemical extraction protocols give the highest EPS extraction yields (calculated by the mass ratio between sludges and EPS dry weight (DW)). Infrared analyses as well as an extraction yield over 100% or organic carbon content over 1 g g⁻¹ of DW revealed, nevertheless, a carry-over of the chemical extractants into the EPS extracts. The EPS of the anaerobic granular sludges investigated are predominantly composed of humic-like substances, proteins, and polysaccharides. The EPS content in each biochemical compound varies depending on the sludge type and extraction technique used. Some extraction techniques lead to a slightly preferential extraction of some EPS compounds, e.g., CER gives a higher protein yield.     

Contribution of molecular biology to the prevention of cystic fibrosis. Experience in Lyon

Enzymatic prenatal diagnosis of cystic fibrosis was performed in 113 amniotic fluids and DNA polymorphism was studied in 104 families, including 28 cases with prenatal material analysis. According to the results, the enzymatic diagnosis should be cautiously interpreted when the risk is less than 1/4. In these situations DNA analysis in the parents is very helpful to assess the reliability of enzymatic diagnosis.     

7 cases of trisomy 2q34 leads to 2qter resulting from a familial t(2;8)(q34;23)]

Seven patients from two different families are trisomic 2q34 leads to 2qter due to segregation of a familial t(2;8)(q34;p23). The clinical features are characteristic: microcephaly, a narrow forehead with bossing and temporal retraction, hypertelorism, palpebral fissures slanted downwards, large irides, and a very concave margin of the lower eyelid. Mental retardation is severe with a mean IQ of 50.     

Aluminium speciation in the Vienne river on its upstream catchment (Limousin region, France)

The aim of this study was to investigate the speciation of aluminium in the river Vienne on its upstream catchment (Limousin region, France) over a period of seven years (May 1998-September 2004) in order to assess harmful effects on aquatic life. Two sampling points were selected: the first at 4 km from the spring (Peyrelevade), and the second one at 89 km from the spring (Royères). The aluminium speciation was computed with Mineql+ 4.5 speciation software. Organic matter and phosphorous play a major role in aluminium speciation. If we consider the free aluminium ion (Al3+) as being the only toxic form of aluminium, the concentrations of toxic forms recorded at Peyrelevade and Royères were always below the toxic values for fish. However, if the sum of the concentrations of Al3+, Al(OH)2+, Al(OH)2+ and Al(OH)4- is taken into consideration, the concentration of aluminium recorded may have adverse effects on aquatic life in the upstream catchment of the river Vienne. Al(OH)4- is the major contributor to the concentration in toxic aluminium recorded. In general, Al(OH)4- forms appears in water during the summer with water alkalinisation due to an increase in photosynthetic activities.     

Level of alpha-fetoprotein in maternal serum before and after chorionic villus sampling

To evaluate incidence and severity of feto-maternal transfusion post-chorionic villus sampling (CVS), maternal serum AFP (MSAFP) were determined for 88 patients before and 15 minutes after CVS. To know whether MSAFP elevation could have clinical implications, a questionnaire was sent to the patients researching if they have had haemorrhages, temperature, spontaneous abortion or premature delivery in the period post CVS. Results of the present study indicate that 44.7% of patients present MSAFP significative elevation (greater than or equal to 8 micrograms/l), a variable elevation (from 8 to 423 micrograms/l). There is no relation between MSAFP elevation and unfavourable events post CVS.