Microleakage of three conventional glass ionomers using 45Ca and methylene blue.

This study sought to compare the sealing ability of two conventional ionomers and a new intermediate/provisional ionomer formulation using sequential applications of two different tracer methodologies. Thirty freshly extracted (< 6 months) human third molars, stored in 0.1% sodium azide solution, were divided randomly into three experimental groups for preparation of simulated Class V caries at the cementoenamel junction of the facial surfaces.

Sex ratio and absence of uniparental disomy in spontaneous abortions with a normal karyotype.

A series of spontaneous abortions collected in the South Wales region over a period of 18 months was karyotyped to identify those with a normal chromosome complement. Microsatellite polymorphisms distributed throughout all autosomes were typed by the polymerase chain reaction to determine the parental origin of each autosome pair in karyotypically normal spontaneous abortions. In 35 cases biparental inheritance of every autosome pair was demonstrated.

Solid tissue culture for cytogenetic analysis: a collaborative survey for the Association of Clinical Cytogeneticists.

Aims: To survey the diagnostic service provided by UK laboratories for the culture of solid tissue samples (excluding tumours) and in particular to examine the variation in culture success rates and the problems of maternal cell overgrowth.

Methods: Twenty seven laboratories took part in a collaborative survey during 1992. Each laboratory submitted data on up to a maximum of 60 consecutive specimens (n = 1361) over a six month period.

Rapid prenatal diagnosis of Patau's syndrome in a fetus with an abdominal wall defect by 72 hour culture of cells from amniotic fluid.

A woman in the 32nd week of pregnancy was referred for investigation because of fetal abnormalities, including an abdominal wall defect, detected by ultrasonography. In view of the increased risk of chromosome abnormality, amniocentesis was performed to enable informed decisions about the management of the pregnancy and delivery to be taken. Cells from the liquor were inoculated into standard lymphocyte culture medium and incubated for 72 h.

A family with three sisters with the 4p- syndrome, originally reported as suffering from the Smith-Lemli-Opitz syndrome.

The authors further describe investigations of a family originally reported by Bundey & Smyth in 1974 with a diagnosis of the Smith-Lemli-Opitz syndrome. Chromosome studies performed for the fourth time revealed that the mother had a presumptive t(4;22) translocation. The importance of reviewing earlier diagnoses, including repeating the chromosome studies if indicated, in order to arrive at a more accurate diagnosis is stressed.

Translocation t(11;13) and deletion of chromosome 7 in a patient with acute myelomonocytic leukemia.

A translocation between chromosomes 11 and 13, together with a deletion of the long arm of chromosome 7, was found in the bone marrow of a patient with acute myelomonocytic leukemia (AMMOL). All three breakpoints are believed to be associated with a predisposition to malignancy.

Premature chromosome condensation in childhood acute lymphoblastic leukaemia: correlation of proliferative potential index in blood and marrow.

The proliferative potential index (PPI), which is the proportion of all GI cells which are in late GI, has been shown to reflect disease state in patients with acute leukaemia. We have determined PPI in paired blood and marrow samples from children with acute lymphoblastic leukaemia (ALL) at different stages of the disease, and found a close correlation between blood and marrow PPI irrespective of disease stage. Therefore blood PPI can replace marrow PPI for monitoring disease control in ALL.

Enzyme-linked immunosorbent assay for detection of leukocidin toxin from Staphylococcus aureus in bovine milk samples.

An enzyme-linked immunosorbent assay was developed for the detection of leukocidin toxin from Staphylococcus aureus. The minimum concentration of leukocidin detectable with the assay was 30 ng/ml. The enzyme-linked immunosorbent assay was found to be a more sensitive method, by a mean of 45-fold, for leukocidin detection than was observation of cytolytic effects of the toxin on bovine neutrophils.

Are double translocations double trouble?

Double translocation heterozygotes are rare, but need not necessarily pose more of a counselling problem than single reciprocal translocation heterozygotes. Nine cases of double translocation are presented, together with a review of the few reports published to date. An attempt is made to provide simple counselling guidelines in the assessment of the risk of producing a liveborn abnormal child.

Nylon bead enzyme-linked immunosorbent assay for detection of sub-picogram quantities of Brucella antigens.

An indirect sandwich enzyme-linked immunosorbent assay, using antibody covalently coupled to nylon beads, has been adapted for the detection of Brucella antigens. Optimum conditions were achieved by incubation of 1 ml of reaction mixture with a single bead, and by minimizing nonspecific interactions through the use of beads coated with purified bovine antibodies, preabsorption of third layer rabbit antibodies with normal bovine serum, and treatment of beads with normal goat serum before addition of the goat anti-rabbit enzyme conjugate. Beta-galactosidase was selected for use with clinical samples primarily because of low levels of endogenous enzyme in bovine leukocytes.

The effect of the male contraceptive agent Gossypol on human lymphocytes in vitro: traditional chromosome breakage, micronuclei, sister chromatid exchange, and cell kinetics.

The male antifertility agent Gossypol did not affect the level of traditional chromosome breakage or number of micronuclei in 66-hour lymphocyte cultures at concentrations up to 40 micrograms/ml. It did increase the frequency of SCE slightly, although the inter-individual variation was greater than the increase resulting from Gossypol, and, even at the highest concentration (40 micrograms/ml), the SCE rate was still within the normal range. It also affected cell kinetics, reducing the mitotic index and the proportion of second and third metaphases after BUdR incorporation.

Outer membrane proteins of Brucella abortus: isolation and characterization.

Outer membrane proteins were derived from one rough and four smooth strains of Brucella abortus by sequential extraction of physically disrupted cells with N-lauroylsarcosinate and dipolar ionic detergent. Extraction of outer membrane proteins was ineffective, however, without predigestion with lysozyme. Three groups of proteins were present and could be separated in their native state by sequential anion-exchange chromatography and gel filtration.

Maternal factors associated with fetal chromosomal anomalies in spontaneous abortions.

The effect is described of maternal factors on the proportion of fetal chromosomal anomalies in a series of 2620 spontaneous abortions, of which 992 specimens were karyotyped. Maternal age was the most important factor associated with a rise in the proportion abnormal, followed by Social Class I or II and the use of oral contraception before conception. The problem of extrapolating from the proportion abnormal to absolute incidence of anomalies is discussed.

A cytogenetic study of human spontaneous abortions using banding techniques.

The karyotypes of 941 singleton and 42 twin abortuses and 4 cystic placentae were determined. 30.5% of the singletons were chromosomally abnormal; 49.

Congenital malformations of the central nervous system in spontaneous abortions.

A study of 2620 pregnancies ending in spontaneous abortion revealed a CNS defect in 3.6% of embryos and fetuses, and 3% of all complete conceptuses. The type of malformation observed varied with the gestational age at expulsion, encephaloceles being predominant in earlier specimens, while more typical anencephalus and spina bifida were more common among later abortions.

Previous reproductive history in mothers presenting with spontaneous abortions.

Information on the previous reproductive history of 3467 mothers presenting with a spontaneous abortion is compared with that of a control series presenting with a livebirth. In 1384 abortions the chromosome constitution of the fetal products was determined. The mothers who had delivered a chromosomally normal abortion more often had a history of previous repeated abortions, while those of chromosomally abnormal abortions tended to have fewer repeated abortions but an excess of previous viable children with Down's syndrome.