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The somatic cell hybrid C121, with chromosome 7 as its sole human component, arose when mouse macrophages were immortalized by fusion with SV40-transformed human fibroblasts. The transforming SV40 genomes are integrated at 7q31-7q35. We show that hybrids with a reduced chromosome 7 component, but which retain markers linked to the cystic fibrosis locus, can be generated by direct in vivo tumor selection or following chromosome-mediated gene transfer and SV40-mediated cellular transformation. Our methods for chromosome fragmentation and fine-structure mapping can now be applied to the substantial number of SV40-transformed human cell lines, with independent chromosomal integration sites, already available. Our results also suggest that expression of human epidermal growth factor receptor augments the tumorigenic potential of the SV40-transformed C121 hybrid.

Patient collapse is a problem requiring rapid and effective management. The Mersey Region strategy for preparing dentists and practice personnel to deal with this situation is to train them by means of practical teaching courses held in the dental surgery. The nature of this course is described.

The relationship of body and placental weight with plasma levels of insulin, glucose, glucagon, glucocorticoids and somatomedins in fetal rabbits between 22 days of gestation and term has been investigated. At 22, 24, 26, 28 and 30 days gestation, body and placental weights were strongly correlated and were also significantly correlated with log transformed plasma insulin concentrations in individual fetuses from nulliparous does. At 30 days gestation, mean plasma insulin levels, as well as body and placental weights, were significantly elevated in fetuses from multiparous does (p less than 0.05) and in fetuses whose growth had been increased by surgical reduction in litter size on day 9 of pregnancy (p less than 0.001). Log insulin concentrations in fetuses from multiparous does and in litter-reduced fetuses were also significantly correlated with bodyweight. The correlation coefficient for log insulin and bodyweight in all individual rabbit fetuses at 30 days gestation was 0.69 (p less than 0.001, n = 116). Fetal log plasma glucagon concentrations at 26 and 28 days gestation were negatively correlated with body weight, but were not significantly related at 30 days gestation. Neither glucose nor glucocorticoid concentrations were significantly related to bodyweight in individual fetuses. Plasma somatomedin activity in litter-reduced fetuses at 30 days gestation, was significantly higher (p less than 0.02) than in normal fetuses, but was not significantly correlated with fetal body weight. The observation of strong positive correlation between insulin and bodyweight throughout the last third of gestation reinforces the belief that fetal insulin plays an important role in the regulation of both placental and fetal growth.

Trisomy 8, in mosaic or non-mosaic form is an extremely rare chromosomal condition in man. Liveborn subjects usually present with mental retardation, bone and joint anomalies and a variety of other physical anomalies. The mental retardation associated with the condition is, however, usually moderate compared to that found in other viable human autosomal trisomic conditions. The present report describes a trisomy 8 mosaic male subject with normal IQ and near-normal phenotype, ascertained through infertility. Chromosome studies on peripheral blood lymphocytes reveal a pure trisomy 8 constitution; cultured skin fibroblasts show 46,XY/47,XY+8 mosaicism. At meiosis, the extra No. 8 chromosome is missing from the germ line. The testicular histology indicates a germ cell maturation arrest in many spermatocytes and the patient is severely oligospermic. Biochemical studies to assay levels of glutathione reductase, a red cell enzyme, the gene for which resides in chromosome 8, show increased levels in the trisomy 8 patient compared with controls.

We used the fluorescence-activated cell sorter (FACS) to select a series of somatic cell hybrids with deleted or translocated chromosome 11 segregated from its normal homolog. Analysis of these cell hybrids with gene-specific probes and for cell-surface marker expression has allowed us to order the markers and define a smallest region of overlap (SRO) for deletions associated with the WAGR (Wilms' tumor, aniridia, genitourinary abnormalities, and mental retardation) region of chromosome 11. Two translocation breakpoints in 11p13 (one associated with familial aniridia and one with a sporadic case of congenital renal dysfunction resulting from urethral and ureteral atresia) map within this SRO.

The value obtained for the difference in radial velocity between components of a visual binary that is unresolved on the spectrograph slit appears to depend, sometimes, on whether the measurement is made visually with a microscope or by means of an oscilloscopic setting device. This apparent dependence has been confirmed by measurement of artificially produced double-lined spectrograms, and disappears for line pairs separated by more than 1.5 or 2 times the half-widths of their components. The dependence arises from blending of the two line profiles. There is some evidence that the results obtained from visual measures are affected by the scale of the image being measured. For this reason, oscilloscope measures are probably to be preferred; although their errors are sometimes larger, they seem to be more consistent. Errors arising from this sort of blending are not sufficient to explain measures of relative radial velocity of the components of some visual binaries, that differ widely from the predictions made from the visual orbits.

The basic gene defect in the autosomal recessive disorder cystic fibrosis has not been identified, and no firm linkage of the disorder to any other marker has been reported. However, a serum protein abnormality present in unaffected heterozygotes as well as in affected homozygotes has been described1, and immunological quantitation of this protein, termed cystic fibrosis antigen, allows the three genotypes to be distinguished2,3. We show here that an immunologically indistinguishable protein is present at high concentrations in granulocytes from normal and cystic fibrosis individuals as well as in myeloid leukaemia cells. Somatic cell hybrids between the mouse myeloid stem-cell line WEHI-TG and myeloid leukaemia cells express cystic fibrosis antigen only when human chromosome 1 is present.

Sacciform cells containing an acidophilic, proteinaceous secretion, were identified in the epidermis of the brown trout and Arctic char. This cell type increased in number during the chronic stages of infestation by the ectoparasitic flagellate, Ichthyobodo sp., in immature brown trout, and decreased during sexual maturation in male brown trout and char. It is suggested that the salmonid sacciform cell produces a secretion which protects the fish against infestation or damage by skin parasites.

TREE-RING investigations in Europe are largely based on the method initiated by Huber in 1938 at Tharandt (near Dresden)1 by which the widths of the rings are measured and the resulting sequence charted and compared both visually and by computer. In temperate zones such as England and the Low Countries oak panels are ideal for the study of dendrochronology as they were prepared from the butt logs of elite trees of slow and even growth. A panel used as a support for a painting has the added advantage that its edges are accessible2. Since 1971 I have worked on 115 of those used by portrait painters in South-east England or Flanders between 1450 and 1620 (refs 3, 4). The boards (there are more than one on some panels) have an average of 200 rings of mean width 1.5 mm.

THE contrasting magnetic behaviour (Table 1 and Fig. 1) of the α- and β-forms of RuCl3 is of interest in relation to the different types of stereochemical arrangements1 shown by the transition metal halides: it has also allowed the presence of α-RuCl3, produced in the usual method of preparation of β-RuCl3, to be detected. A material, hitherto considered2,3 as yet another form of RuCl3, is now shown to be Ru2IVOCl6 (Table 1), a member of a class of oxide chlorides of binuclear ruthenium in which the average oxidation state of ruthenium changes from +4 through +3.5 to +3.

No previous studies of memory in children with left or right brain lesions have been reported, despite known sequelae in other aspects of learning. Memory for verbal (V) and nonverbal (NV) stimuli was evaluated here through a selective reminding task in which animal names (V) and dot patterns (NV) were learned over 8 trials. Measures of V and NV long-term storage (LTS) and cumulative long-term retrieval (CLTR) were made. 18 left lesioned (LL), 13 right lesioned (RL), and 31 age, sex, and SES matched control (C) children were included. All LLs and RLs had CT scan confirmation of unilateral lesions of vascular origin and were >1 yr. post lesion onset. M age at lesion onset was 4.05±4.59; M age at test was 9.42±3.89. M IQ for all groups was within normal limits, but IQ for RLs was significantly lower than for Cs. M T-scores, derived from age norms, SD and Ms adjusted for IQ differences+ were: Multivariate analyses revealed significant differences as noted above. These findings suggest that LLs store V and NV information, but do not retrieve V information normally. RLs have difficulty retrieving NV and also storing V information, possibly due to attentional limitations. These memory deficits correspond to lesion lateralization and hold implications for education.

IN a large class of gaseous chemical reactions, the mechanism is generally supposed to be the following. Molecules are brought into an activated state by collision. Most of the activated molecules are deactivated again, but during their existence there is a definite probability of their chemical transformation. As is well known, the relation between reaction rate and pressure under these conditions is such that the reciprocal of T, the half life of the reacting substance, gives a curve of type 1 or 2 (see Fig. 1) when plotted against the initial pressure1. (The precise shape of the curve before it has become horizontal depends upon how the above mentioned probability varies with the total energy of the molecule2.)