Formaldehyde in cryoprotectant propanediol and effect on mouse zygotes

Cryopreservation of human zygotes and embryos has been routinely performed by in-vitro fertilization clinics for many years. Karran and Legge (1996) first reported that formaldehyde (FA) present in the cryoprotective solutions can have a deleterious effect on mouse oocytes. FA is a cytotoxic, carcinogenic and mutagenic chemical. The effect of FA on mouse zygotes was investigated. In addition, the concentrations of FA in propanediol (PROH) obtained from various sources were determined. Pooled 1-cell embryos were dispensed into droplets of modified Ham's F10 or human tubal fluid containing various concentrations of FA. Since bovine serum albumin (BSA) may minimize toxicity additional trials were done as above in the absence of BSA. FA concentration in the standard 1.5 M PROH, from different sources in water, was measured in the same assay using a standard curve of 0-100 microM FA. FA in a complex medium had a significant deleterious effect on embryo development and hatching but only at 1 mM concentration (P < 0.000001; see Tables I-III). There was no significant effect of FA at 100 microM. However, in a simple medium even 50 microM FA decreased embryo hatching. FA was present in 1.5 M PROH from different sources (range 1.0-35.3 microM concentration). It appears that FA concentrations do not increase with storage because FA concentrations were low even after opening and storage for 3 years on the shelf. This suggests that FA is a contaminant during the manufacturing process and may vary from manufacturer to manufacturer and batch to batch. Until further studies are done to confirm the lack of toxicity to embryos during cryopreservation (with or without FA scavengers) it may be prudent to screen all batches of cryoprotectants for FA as part of quality control.      

Copolymères du chlorure de vinylidène avec l'acrylonitrile,le chlorure de vinyle et le méthacrylate de méthyle, 2. Fusion — utilisation d'un modèle de simulation

The melting point depression in vinylidene chloride copolymers, when introducing an increasing number of units B = vinyl chloride, acrylonitrile or methyl methacrylate is studied in this paper. A Monte-Carlo simulation model of chains growing and crystallization is applied and allows to know the proportion X_c of defects in the crystalline phase. An equation given by Sanchez is then applied, and the excess energy ε of the defect created by the incorporation of a B unit in the crystalline vinylidene chloride lattice is calculated.     

Association of D/D translocations with fetal wastage and aneuploidy. A report of four families.

Four families are described with a t(13q14q) segregating. Two of them were identified through index cases with Down's syndrome; their karotypes revealed the unusual 46,XY, -13, -14, +t(13q14q), +21. The other two families were identified through a chromosomal study of parents with repeated spontaneous abortions. Analysis of data on 3 of these 4 families and on 7 other from the published reports showed no evidence of increased fetal wastage among 13/14 carriers. However, the risk of producing offspring with various types of aneuploidy may be greater among carriers than among persons with a normal chromosome pattern. Qualitative and quantitative differences in D/D translocations may account for the observed variation in clinical findings. These differences add to the problem of determining genetic risks from an analysis of grouped data.     

Three cell line mosaicism involving structural and numerical abnormalities of chromosome 18 in a 3.5-year-old girl: 47,XX,+18/47,XX,+del(18)(q22)/46,XX

We report on a 3.5-year-old girl with a mosaic karyotype including full trisomy 18, normal cells and a majority of cells with partial trisomy involving an extra chromosome 18 deleted at band q22. She had cardiac and CNS anomalies, dysmorphic facial features failure to thrive and developmental delay. A gastrostomy tube was placed at 2 years of age. The combination of improved nutrition and optimal developmental therapy has led to her sitting supported, attempting to stand and enhancement of her cognitive and non-verbal communication abilities. Molecular investigation of the patient and her parents using microsatellite analysis has led to the conclusion that, as expected, the additional copy of chromosome 18 constituting the full trisomic cell line is maternal meiosis I in origin. The data, however, indicate that in the trisomic cell line containing the deleted chromosome 18q, the structurally abnormal 18 was of paternal origin. We think this case is the first described with both structural and numerical trisomic mosaicism involving chromosome 18 in a liveborn infant. We propose a mechanism of origin and review the literature, comparing the clinical presentation of this case with individuals having full or partial trisomy 18.     

Intermediate filament expression by normal and diseased human corneal epithelium

Cicatricial conjunctivitis may be a sequel to systemic disorders (eg, Stevens-Johnson syndrome, cicatricial pemphigoid) or local disorders such as chemical burns. The cicatrisation is often associated with corneal epithelial changes that cause visual loss. These have been attributed to encroachment of the conjunctival epithelium over the cornea. However, the epithelial anomalies are poorly understood. We investigated the corneal epithelial changes in cicatricial conjunctivitis with an immunohistochemical study of intermediate filaments in normal and pathological specimens. Our results show that the normal corneal epithelium is immunoreactive for cytokeratin 3 (CK 3) but not cytokeratin 19 (CK 19), whereas normal conjunctival epithelium is CK 3 negative and CK 19 positive. Conjunctiva artificially transposed over the cornea (after therapeutic conjunctival flap reconstruction) retained the normal pattern of conjunctival cytokeratin expression (CK 3 negative, CK 19 positive). Conversely, the entire corneal epithelium exhibited the normal cytokeratin pattern (CK 3 positive, CK 19 negative) in 82% of Stevens-Johnson, 80% of cicatricial pemphigoid, and 69% of chemical burns specimens. The findings suggest that conjunctival encroachment is not responsible for the changes at the corneal surface in cicatricial conjunctivitis and that the abnormal corneal epithelium is derived from native corneal cells in these diseases.     

Phonomechanocardiography in dilated cardiomyopathy

Twenty seven patients with dilated cardiomyopathy (DCM) were studied by phonocardiography and mechanocardiography. The diagnosis was made in each case by history, laboratory, echocardiogram, hemodynamic study and coronary arteriography. Patients with left complete bundle branch block were excluded. As controls we studied 24 subjects with comparable age an sex. The phonomecanocardiographic records were performed with a Siemens-Elema machine (Mingograph-34) with direct ink recording with electrocardiogram in lead DII, phonocardiogram in mitral focus, and carotid pulse or apexcardiogram (ACG) simultaneously. The following data were assessed: heart rate (HR) electromechanical interval (Q-S2), preejection period of left ventricular contraction (PEP), left ventricular ejection time (LVET), relative ejection period (REP), ratio PEP/LVET (IW), "a" wave of the ACG ("a" wave), rising period of the apex-cardiogram (RPACG), isovolumic relaxation time (IRT), first heart sound intensity (S1I), third and fourth heart sound presence (S3 and S4) respectively. The average values (mean) and their standard deviation for the groups (N) and DCM respectively were: HR (b/m): 67.08 +/- 7.67 and 88.84 +/- 15.31; Q - S2 (msec.): 554.23 +/- 28.37 and 561.35 +/- 30.99; PEP (msec.): 145.13 +/- 17.64 and 194.11 +/- 22.09; LVET (msec): 409.38 +/- 27.68 and 375.54 +/- 28.21; REP (%): 102 +/- 9.27 and 84.78 +/- 8.61; IW: 0.395 +/- 0.078 and 0.72 +/- 0.11; "a" wave (%): 7.37 +/- 2.15 and 19.47 +/- 6.76; RPACG (sec.): 0.093 +/- 0.0015 and 0.143 +/- 0.067; IRT (sec.): 0.094 +/- 0.0012 and 0.105 +/- 0.018.(ABSTRACT TRUNCATED AT 250 WORDS)