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Notes: Summary Pedigrees of all known cases, on Shetland, of Down's syndrome, cytogenetically confirmed as trisomy 21, and of a control for each patient matched by birth date, sex and birth place, were traced over a minimum of eight generations. Mean kinship coefficients in all pairs of Down's syndrome patients and in all pairs of controls were similar. The kinship between the father and mother of each case shows that the parents are more closely related than the general level of relationship in the population, suggesting some recessive element in the etiology. It is argued that the effect of the resulting increased homozygosity would be to prevent the loss of the conceptus that occurs in the majority of trisomy 21 conceptions.

Notes: Abstract Cyclosporin (CsA) is currently the main immunosuppressive agent used in organ transplantation with considerable improvement in graft survival. Oral CsA solution is highly lipophilic, and its bioavailability may be reduced in cystic fibrosis (CF) heart-lung transplant recipients with pancreatic, gastrointestinal, and hepatic insufficiency. The bioavailability of oral CsA solution in 7 CF transplant recipients (5 male and 2 female with a mean age of 27 years and a mean weight of 49 kg) and 3 non-CF heart-lung recipients (1 male and 2 female with a mean age of 41 years and a mean weight of 60 kg) was studied. Following intravenous CsA administration, the kinetic curves were similar with no significant difference in the volume of distribution and clearance of CsA demonstrated between the CF and non-CF groups. The mean daily dose of oral CsA in 7 CF subjects (23.3 mg·kg−1) was significantly higher than the 3 non-CF heart-lung recipients (4.8 mg·kg−1). The mean maximum blood concentration of CsA for the oral dose was 776 ng·ml−1 for the 7 CF subjects, which was comparable with the mean peak values of 789 ng·ml−1 for the 3 non-CF control subjects. Poor enteral absorption of CsA probably accounts for the significantly lower mean bioavailability in the 7 CF subjects (14.9%) compared with the 3 non-CF control subjects (39.4%). The effects on the bioavailability of oral CsA solution by pancreatic enzymes (Creon) and histamine-2 antagonist (ranitidine) were also evaluated in the 7 CF subjects. No significant difference was demonstrated.

Notes: A method for imaging magnetic domain structures in the transmission electron microscope is described. Coherent Foucault imaging provides a direct means of producing a magnetic interferogram which reveals the quantitative distribution of magnetic induction across the specimen. The technique requires the high coherence of a field-emission gun system and the ability to position an aperture accurately to cut part of the diffraction pattern. A simple analytical theory, together with computer simulations and experimental results, is presented to demonstrate the power of the technique.

Notes: Translational fusions between a mutant phoA (lacking its promoter, ribosomal binding site and signal peptide sequence) and Rhizobium‘symbiotic’ genes were isolated. Since these fusions expressed alkaline phosphatase (AP), the product of phoA, the genes into which phoA was inserted apparently specify proteins located in the bacterial periplasm or cell membrane, the compartment in which AP has activity. These genes were psiA and genes upstream of psiA (psiA is required for normal nodule development and strains with multicopy psiA fall to make exopolysaccharide (EPS) and to nodulate). Fusions between phoA and pss (exo) genes, which are required for EPS production, also resulted in the expression of AP indicating that products of these pss genes were located at the cell surface. Using grus fusions to psiA and pssA, we found that the former was expressed in N2-fixing bean root nodules but the latter was not.

Notes: Abstract Peraluminous granitoid magmas are a characteristic product of ultrametamorphism leading to anatexis of aluminous metasedimentary rocks in the continental crust. The mechanisms and characteristic length-scales over which these magmas can be mobilized depend strongly on their melt fraction, because of their high viscosities. Thus, it is of fundamental importance to understand the controls exerted by pressure, temperature and bulk composition of the source material on melt productivity. We have studied experimentally the vapour-absent melting behaviour of a natural metapelitic rock and our results differ greatly from those of previous experimental and theoretical investigations of melt productivity from metamorphic rocks. Under H2O-undersaturated conditions, bulk composition of the source material is the overriding factor controlling melt fraction at temperatures on the order of 850–900° C. Granitoid melts formed in this temperature interval by the peritectic dehydration-melting reaction: $$\begin{gathered} Biotite + plagioclase + aluminosilicate + quartz \hfill \\ = melt + garnet \hfill \\ \end{gathered} $$ have a restricted compositional range. As a consequence, melt fractions will be maximized from protoliths whose modes coincide with the stoichiometry of the melting reaction. This “optimum mode” (approximately 38% biotite, 32% quartz, 22% plagioclase and 8% aluminosilicate) reflects the fact that generation of low-temperature granitoid liquids requires both fusible quartzo-feldspathic components and H2O (from hydrous minerals). Metapelitic rocks rich in mica and aluminosilicate and poor in plagioclase contain an excess of refractory material (Al2O3, FeO, MgO) with low solubility in low-temperature silicic melts, and will therefore be poor magma sources. Melt fraction varies inversely with pressure in the range 7–13 kbar, but the effect is not strong: the decrease (at constant temperature) over this pressure range is of at most 15 vol% (absolute). The liquids produced in our experiments are silicarich (68–73 wt% SiO2), strongly peraluminous (2–5 wt% normative corundum) and very felsic (MgO+FeO* +TiO2 less than 3 wt%, even at temperatures above 1000° C). The last observation suggests that peraluminous granitoids with more than 10% mafic minerals (biotite, cordierite, garnet) contain some entrained restite. Furthermore, because liquids are also remarkably constant in composition, we believe that restite separation is more important than fractional crystallization in controlling the variability within and among peraluminous granitoids. We present liquidus phase diagrams that allow us to follow the phase relationships of melting of silica-and alumina-saturated rocks at pressures corresponding to the mid- to deep-continental crust. Garnet, aluminosilicate, quartz and ilmenite are the predominant restitic phases at temperatures of about 900° C, but Ti-rich biotite or calcic plagioclase can also be present, depending on the bulk composition of the protolith. At temperatures above 950–1050° C (depending on the pressure) the restitic assemblage is: hercynitic spinel+ilmenite+quartz±aluminosilicate. Our results therefore support the concept that aluminous granulites (garnet-spinel-plagioclase-aluminosilicate-quartz) can be the refractory residuum of anatectic events.