The “specific” binding of insulin to polyethene and other materials

It is known that insulin is adsorbed onto glass but it has been assumed that it is not adsorbed onto plastic. We find that tritium-labelled insulin is adsorbed onto all materials tried. The adsorption is reduced in the presence of other proteins and can be prevented altogether by coating the vessels with cetyl alcohol.     

Regression of blood vessels precedes cartilage differentiation during chick limb development

We have previously investigated distinct areas of vascular regression in the developing vascular system of the chick limb bud. Avascular areas appear in a characteristic spatial and temporal pattern, and are correlated with the position of developing cartilage. In the present study, we examined limb-bud sections which had been double labeled for endothelial cells and developing cartilage in order to determine the relationship between the appearance of cartilage and the disappearance of capillaries. Endothelial cells, which specifically take up acetylated low-density lipoprotein (acLDL), were labeled by intravenously injecting fluorescent acLDL (DiIacLDL) into chick embryos at Hamburger and Hamilton stages 26-30. Avascular zones, which correspond to the developing digits, were clearly visible within the fluorescently labeled distal vasculature. The same sections were labeled with monoclonal antibodies specific for cartilage. We found that progressing avascularity in the digital regions was followed by increased staining for cartilage antigens in the same areas. Zones of avascularity always developed earlier than morphologically and immunologically detectable cartilage in all planes of section and were always larger than the areas of cartilage. These results demonstrate that blood vessels disappear in predictable areas prior to the overt differentiation of cartilage.     

Mortality among male anaesthetists in the United Kingdom, 1957-83.

A cohort of 3769 male anaesthetists resident in the United Kingdom between 1957 and 1983 was followed up for a total of 51,431 person years of observation. All subjects were fellows of the Faculty of Anaesthetists and held full registration with the General Medical Council. With all men in social class I being taken as the standard, the standardised mortality ratio among anaesthetists for all causes of death was 68 (95% confidence interval 59 to 77) and the standardised mortality ratio for all cancers was 50 (95% confidence interval 36 to 67). There was no significant excess mortality from lymphomas or leukaemias, but 16 of the 221 deaths in anaesthetists were due to suicide, giving a standardised mortality ratio of 202 (95% confidence interval 115 to 328). When anaesthetists were compared with all doctors the standardised mortality ratio for suicide was only 114, a nonsignificant excess. These findings confirm that the risk of suicide among anaesthetists is twice as high as among other men in social class I but suggest that the risk does not differ significantly from that among doctors as a whole. There was no evidence of a significant excess risk of cancer, and, in particular, the small excess of cancer of the pancreas reported previously could not be confirmed.     

Obolinga,a new genus of Mimosaceae tribe ingeae from Hispaniola

Obolinga zanonii Barneby is described as a new monotypic genus from disturbed cloud forest of the Sierra de Bahoruco—Massif de la Selle mountain system in southeastern Haiti and southwestern Dominican Republic. The genus is to be added to tribe Ingeae of Mimosaceae, and is believed on the basis of gross morphology, wood anatomy, and pollen structure to be nearest to the genusCojoba. From this it differs in a massive terete pod completely filled with a stack of large discoid seeds clothed in a lustrous papery testa and inertly dehiscent on the ground. The structurally comparable fruit of the Malayan genusCylindrokelupha, currently referred toArchidendron, is ascribed to parallelism. The species is illustrated with line drawings.     

Cell attachment properties of collagen type VI and arg-gly-asp dependent binding to its α2(VI) and α3(VI) chains

Twelve of sixteen different cell types including fibroblasts and tumor cells were able to attach and spread on substrates of pepsin-solubilized or intact collagen VI, and on its triple helical domain. Attachment and spreading were independent of soluble mediator proteins (fibronectin, laminin) and collagen VI was distinct from collagens I, IV and V in the cells with which it interacted. Many of the same cells bound and spread on substrates prepared from unfolded α2(VI) and α3(VI) chains but not on the α1(VI) chain. The interactions with the chains were inhibited by low concentrations (10–100 μM) of synthetic RGDS and RGDT but not RGES peptides while the binding of cells to pepsin-solubilized collagen VI was more than 20-fold less sensitive to these peptides. The data incidate that cells have the ability to bind to collagen VI in a specific manner suggesting a similar function for collagen VI in situ.     

Cytogenetic and molecular characterization of a newly established neuroblastoma cell line LS

Summary A new human neuroblastoma cell line (LS) that originated from an abdominal tumor of a 16-month-old girl is presented; it was classified, according to Evans, as being stage III. Morphological (dense-core particles) and biochemical characteristics (dopamine--hydroxylase, acetylcholinesterase, neuron-specific-enolase) confirmed the diagnosis. In addition to a slightly variable modal chromosome number of 48 or 49 (because of marker-chromosomes and autosomal trisomies), cytogenetic analysis revealed two constantly appearing chromosomes with homogeneously stained regions (HSR's). The karyo-type remained constant over 50 passages in vitro [49,XX, –12,+der5, + 17,+mar1,+mar2]. Double minutes were a rare phenomenon and appeared only in a few metaphases. In situ hybridization showed that some of the HSR's consisted of amplified N-myc copies. The distribution of the N-myc copies according to in situ hybridization signals along the HSR's was compared with the data of Southern and Northern blotting analyses.     

The identity and synonymy of Acacia guilandinae,Mimosa obovata,M. pseudo-obovata,and M. laticifera (Mimosaceae)

Acacia guilandinae DC. is recognized asMimosa guilandinae (DC.) Barneby, endemic to French Guiana and adjoining Amapá, Brazil;M. pseudo-obovata is subordinated as a Brazilian var.pseudo-obovata (Taub.) Barneby to CaribbeanM. ceratonia L.; andM. laticifera is found synonymous withM. obovata Benth. Diagnostic morphological characters of each taxon are presented in key form.