Smoking during pregnancy and placental pathology

The pathological study of all placentas from women smoking at least five cigarettes daily during pregnancy (248 cases) and of those placentas from a corresponding control group randomised among all the non-smokers (196 cases) has been set up at the maternity hospital of Haguenau (France) since 1974. The systematic histological examination has shown among smokers a higher frequency of abonormal trophoblast and especially of nuclear clumps in the syncytiotrophoblast. On the other hand, according to a standard protocol, the grouping of various abnormalities has shown, among smokers, a higher frequency of "signs of hypoxia". The lack of relationship between these "signs of hypoxia" and the well-known decreased birthweight among smokers suggests that smoking during pregnancy could always go with a decreased birthweight without a corresponding decreased placental weight, and seldom with an intra-uterine hypoxia. These two effects are independent.     

Spatial mapping in the primate sensory projection: Analytic structure and relevance to perception

The retinotopic mapping of the visual field to the surface of the striate cortex is characterized as a longarithmic conformal mapping. This summarizes in a concise way the observed curve of cortical magnification, the linear scaling of receptive field size with eccentricity, and the mapping of global visual field landmarks. It is shown that if this global structure is reiterated at the local level, then the sequence regularity of the simple cells of area 17 may be accounted for as well. Recently published data on the secondary visual area, the medial visual area, and the inferior pulvinar of the owl monkey suggests that same global logarithmic structure holds for these areas as well. The available data on the structure of the somatotopic mapping (areaS-1) supports a similar analysis. The possible relevance of the analytical form of the cortical receptotopic maps to perception is examined and a brief discussion of the developmental implications of these findings is presented.This work was supported by Grant No. 1 F32MH05367-01 from the USPHS, ADAMHA     

The effect of adenylate cyclase inhibitor (ACI) on guanylate cyclase, phosphodiesterase and other enzymes in heart.

The effect of an inhibitor of adenylate cyclase (ACI) was measured on some enzymes associated with cyclic nucleotide-regulated metabolism. Soluble guanylate cyclase was inhibited; both soluble and particulate cyclic GMP-phosphodiesterases were stimulated. Cyclic AMP phosphodiesterases were unaffected. In contrast, the activities of Na, K-ATPase, protein kinase, phosphorylase kinase, glycogen synthetase and a number of glycosidases were not altered by equipotent amounts of the inhibitor. It is concluded that this substance acts as a modulator of both cyclic AMP and cyclic GMP metabolism in heart and other tissues.     

A negative image of the quiescent centre in regenerating root apices of Zea mays

Usually the presence of the quiescent centre in roots is demonstrated by the absence of labelled nuclei following treatment of the root with appropriate radioactive markers. By modification of the pulselabelling technique, a negative image of the quiescent center, showing more intense labelling from [³H]thymidine than the surrounding area, was obtained in regenerating root apices of Zea mays L.     

RADIOIMMUNOASSAY OF METHIONINE-AND LEUCINE-ENKEPHALINS IN REGIONS OF RAT BRAIN AND COMPARISON WITH ENDORPHINS ESTIMATED BY A RADIORECEPTOR ASSAY

Abstract— Radioimmunoassays (RIAs) selective for methionine-enkephalin (Met-ENK) and leucineenkephalin (Leu-ENK) have been developed using competition towards binding of 10 pM ¹²⁵I-enkephalins to antibodies raised in rabbits against ENKs coupled to ovalbumin with carbodiimide. The high sensitivity of the RIAs (IC₅₀ 0.57 n m and 0.55 n m for Met- and Leu-ENK, respectively) allowed estimation of the enkephalin content in extracts of all rat brain regions. Regional levels are compared with those determined on the same extracts by a radioreceptor assay (RRA) using competition towards binding of 5 n m [³H]Leu-ENK to rat striatal membranes. Optimal conditions for killing the animals and extracting the endorphins have been carefully investigated: killing by rapid microwave irradiation was not found necessary as long as brain regions were homogenized into 0.1 n -HCl before deproteinization.
Marked differences both in total endorphins (RRA) and ENKs (RIA) between regions are observed with similar ranking of the various regions: highest levels are found in striatum and hypothalamus and lowest in cerebellum and hippocampus. In each region the total ENK levels (RIA) represent only 2–13% of the total endorphins (RRA) suggesting the presence of large amounts of endorphins other than the ENKs.     

Selection and characterization of bovine aortic endothelial cells

This paper reports techniques for isolation, selection and long-term passage of bovine aortic endothelium (BAE). A [3H]thymidine-selection technique was developed to limit overgrowth of cultures by contaminating smooth-muscle cells. The resulting cultures could be passaged for a replicative life span of 35 to 40 doublings and maintained a stable, normal karyotpye throughout this period. Despite the fact that these cultures reached a stable monolayer with density-inhibited growth state, postconfluent cells showed focal areas of a second growth pattern called "sprouting." This was seen only when cultures were maintained at high densities for periods of 1 to 2 weeks. Ultrastructural analysis, as well as immunofluorescence studies with markers for endothelial cells (factor VIII) and smooth-muscle cells (actin), indicates that this phenomenon is not due to overgrowth of a residual population of smooth-muscle cells, but may represent a second growth pattern of the endothelial cells themselves.     

On the lack of inotropy of cardiac glycosides on skeletal muscle: a comparison of Na+, K+-ATPases from skeletal and cardiac muscle.

Comparison of Na,K-ATPase from skeletal and cardiac muscle revealed that, although the skeletal muscle enzyme was only slightly less sensitive to inhibition by ouabain, the rates of [³H]ouabain binding to, and dissociation from, the skeletal enzyme were much faster than the corresponding rates for the cardiac enzyme. The skeletal muscle enzyme required higher concentrations of potassium to stabilize the ouabainenzyme complex and to stimulate the K⁺-phosphatase activity. The K⁺-phosphatase activity was only 8% of the Na,K-ATPase activity of the skeletal muscle enzyme, compared to 22% for the cardiac preparation. The glycoprotein subunit found in Na,K-ATPases from cardiac and many other tissues appeared to be absent in the enzyme from skeletal muscle. The differences in binding and dissociation rates for ouabain suggest that there may be significant differences in the structure of the digitalis receptor in the two enzymes. The I₅₀ for ouabain inhibition of the skeletal muscle Na,K-ATPase was, however, only slightly higher than for the cardiac enzyme, suggesting that the lack of an inotropic effect of cardiac glycosides on skeletal muscle could not be due to failure of the digitalis drugs to bind to and inhibit the membrane-linked sodium pump.     

Defect in 3'-phosphoadenosine 5'-phosphosulfate synthesis in brachymorphic mice. II. Tissue distribution of the defect

The tissue distribution of the defective PAPS synthetic pathway in homozygous brachymorphic mice ($\text{bm}\text{bm}$) has been investigated using four different criteria: (i) incorporation of ³⁵SO₄^2? into adenosine 5′-phosphosulfate (APS), 3′-phosphoadenosine 5′-phosphosulfate (PAPS), and endogenous macromolecular acceptors, (ii) APS kinase (adenylylsulfate kinase; ATP:adenylylsulfate 3′-phosphotransferase, EC 2.7.1.25) activity, (iii) ATP sulfurylase (sulfate adenylyltransferase; ATP:sulfate adenylyltransferase, EC 2.7.7.4) activity, (iv) thermostability of ATP sulfurylase. With respect to the first three criteria, the results indicate that liver is affected as profoundly as cartilage (K. Sugahara and N. B. Schwartz, Arch. Biochem. Biophys. (1982) 214, 589–601). In contrast, skin and brain show no differences between normal and mutant. Kidney is significantly, but only moderately, affected. The results from thermostability studies demonstrate that ATP sulfurylase activity is more labile in $\text{bm}\text{bm}$ cartilage, liver, and kidney, but not in skin or brain, supporting the above-observed distribution of the defect. Therefore, the present results indicate a multiple, but not universal, tissue distribution of the defective PAPS synthetic pathway in $\text{bm}\text{bm}$ mice. Furthermore, these findings support the suggestion that ATP sulfurylase as well as APS kinase is defective in brachymorphic mice.     

Modification of sialic acid metabolism of murine erythroleukemia cells by analogs of N-acetylmannosamine

Two analogs of N-acetylmannosamine, $\text{2-}\text{acetamido}\text{-1,3,4,6-}\text{tetra}\text{-O-}\text{acetyl}\text{-2-}\text{deoxy-}\text{d}\text{-mannopyranose}$ (Ac₄-NAcMan) and the 2-trifluoroacetamido derivative (Ac₄F₃-NAcMan), were synthesized as potential inhibitors of the formation of sialic acid-containing glycoconjugates and were examined for their ability to modify the incorporation of $\text{N-[}{}^3\text{H]acetylmannosamine}$ into cellular glycoconjugates of Friend murine erythroleukemia cells. Ac₄F₃-NAcMan and Ac₄-NAcMan inhibited cellular replication in suspension culture at concentrations of 0.02 and 0.08 mM, respectively. The cytotoxicity of Ac₄-NAcMan was relatively reversible, whereas that produced by Ac₄F₃-NAcMan was not, as judged by measurement of the cloning efficiencies of cells exposed to these agents. The analogs inhibited incorporation of $\text{N-[}{}^3\text{H]acetylmannosamine}$ into ethanol-soluble and -insoluble materials. Separation of ethanol-soluble metabolites by HPLC demonstrated that Ac₄F₃-NAcMan caused accumulation of radioactivity from $\text{N-[}{}^3\text{H]acetylmannosamine}$ in CMP-N-acetylneuraminic acid (CMP-NeuNAc) equal to the decrease in macromolecular-bound ³H caused by this agent. In contrast, similar exposure to Ac₄-NAcMan produced a large increase in the amount of radioactivity in ethanol-soluble N-acetylneuraminic acid while decreasing the amount of label from $\text{N-[}{}^3\text{H]acetylmannosamine}$ in cellular CMP-NeuNAc, suggesting that the analogs differ in their biochemical sites of action. Treatment of cells with either analog increased the amount of neuraminidase-hydrolyzable sialic acid-like material on the cell surface; this appeared to be due to the incorporation of the analogs into cellular glycoconjugates, since incubation of cells with ³H-labeled analogs resulted in the appearance of radioactivity in cellular ethanol-insoluble and neuraminidase-hydrolyzable material. Incubation of cells with Ac₄-NAcMan labeled with ¹⁴C in the 4-O-acetyl group further demonstrated that incorporation occurred with approx. 50% retention of this substituent. Thus, both the amount and the nature of the surface sialic acid constituents of treated cells were altered, suggesting that these or similar analogs could potentially be used to modify cellular membrane function.