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Ruthenium(II) polypyridyl complexes have gained significant interest as photochemotherapeutics (PCTs) due to their synthetic viability, strong light absorption, well understood excited state properties, and high phototoxicity indexes. Herein, we report the synthesis, characterization, electrochemical, spectrochemical, and preliminary cytotoxicity analyses of three series of ruthenium(II) polypyridyl complexes designed to mimic PCTs. The three series have the general structure of [Ru(bpy)2(N–N)]2+(Series 1), [Ru(bpy)(dmb)(N–N)]2+(Series 2), and [Ru(dmb)2(N–N)]2+(Series 3, where N–N is a bidentate polypyridyl ligand, bpy = 2,2'-bipyridine, and dmb = 6,6'-dimethyl-2,2'-bipyridine). In the three series, the N–N ligand was systematically modified to incorporate increased conjugation and/or electronegative heteroatoms to increase dp-p* backbonding, red-shifting the lowest energy metal-to-ligand charge transfer (MLCT) absorptions from ?max= 454 to ?max= 580 nm, nearing the therapeutic window for PCTs (600–1100 nm). In addition, steric bulk was systematically introduced through the series, distorting the Ru(II) octahedra, making the dissociative 3dd* state thermally accessible at room and body temperatures. This resulted in a 4 orders of magnitude increase in photoinduced ligand ejection kinetics, and demonstrates the ability to modulate both the MLCT* and dd* manifolds in the complexes, which is critical in PCT drug design. Preliminary cell viability assays suggest that the increased steric bulk to lower the 3dd* states may interfere with the cytotoxicity mechanism, limiting photoinitiated toxicity of the complexes. This work demonstrates the importance of understanding both the MLCT* and dd* manifolds and how they impact the ability of a complex to act as a PCT agent.

ObjectiveTo determine the prevalence of newly diagnosed hepatitis C virus (HCV) and associated risk behaviours among men who have sex with men (MSM) in Manchester.MethodA survey among MSM attending four genitourinary medicine clinics in Manchester was carried out over 9 months in 2013. Participants were asked about recent sexual behaviour, recreational drug use and HIV status. All men were offered an HCV test.ResultsOverall, 2030 MSM completed a questionnaire and accepted an HCV test. Of whom, 0.9% (18) were newly diagnosed with HCV, including 1.8% (13/735) of HIV-positive MSM, 0.7% (3/440) of MSM of unknown HIV status and 0.2% (2/855) of HIV-negative MSM. HCV positivity was significantly associated with HIV status (p<0.001). When compared with HIV-negative MSM, HIV-positive MSM had higher rates of sharing snorting drug equipment, injecting drugs/‘slamming’ and using recreational drugs (all p<0.05) but lower rates of five or more sexual partners and insertive unprotected anal intercourse (p<0.05). MSM newly diagnosed with HCV had significantly higher prevalence of unprotected sex, sex with someone HCV positive, fisting, group sex, ever injecting drugs/‘slamming’ and recreational drug use (p<0.002).ConclusionsIn this survey, HIV-positive MSM had significantly different drug use behaviour which may explain the higher HCV burden. However, HCV was also associated with HIV-negative MSM engaging in high-risk sexual practices. All MSM attending sexual health clinics must have a risk assessment and HCV screening should be offered based on the risk. Further studies are warranted to explore the interplay between HCV and HIV risk associated with drug use versus sexual practices.

The retinal vasculature of postmortem normal human and diabetic eyes was studied using an immunohistochemical technique in conjunction with confocal laser scanning microscopy. The technique, which stained for von Willebrand factor, allowed both large areas of the retinal vasculature to be visualised and abnormalities to be studied in detail without disturbing the tissue architecture. Only one microaneurysm, defined as any focal capillary dilation, was observed in 10 normal eyes but numerous microaneurysms were seen in 4 out of 5 diabetic retinas; counts varied between 0 and 26 per 0.41 mm2sample area. Microaneurysms were classified into 3 categories according to morphology: saccular, fusiform and focal bulges. Most were saccular, these having no preferred orientation. The majority of microaneurysms were associated with just 2 vessels suggesting they were unlikely to develop at vascular junctions. The majority were observed to originate from the inner nuclear layer and were therefore in the deeper part of the inner retinal capillary plexus. Variation in the staining of microaneurysms may correlate with endothelial dysfunction seen clinically as dye leakage during fluorescein angiography.

It was previously shown (Roberts, C., Platt, N., Streit, A., Schachner, M. and Stern, C. D. (1991) Development 112, 959-970) that grafts of Hensen's node into chick embryos enhanced and maintain expression of the L5 carbohydrate in neighbouring epiblast cells, and that antibodies against L5 inhibit neural induction by such a graft. We now show that L5 is initially widely expressed in the epiblast, but as neural induction proceeds it gradually becomes confined to and up-regulated in the early neural plate. L5 can therefore be considered as a marker for cells that are competent to respond to neural induction. We also show that Hepatocyte Growth Factor/Scatter Factor (HGF/SF) promotes the expression of L5 by extraembryonic epiblast in collagen gels after overnight culture. Explants cultured for several days in the presence of HGF/SF, as well as explants of prospective neural plate, can differentiate into cells with neuronal morphology expressing neuronal markers. To investigate whether HGF/SF is expressed in the chick embryo at appropriate stages of development, we produced specific cDNA probes and used them for in situ hybridization. We find that at the primitive streak stage, HGF/SF is expressed specifically in Hensen's node. We therefore propose that HGF/SF plays a role during the early steps of neural induction, perhaps by inducing or maintaining the competence of the epiblast to respond to neural inducing signals.

Pieces of tissue were dissected from early chick and quail embryos (Stages XTII and XIV of Eyal-Giladi & Kochav, 1976; and stages 3–5 of Hamburger & Hamilton, 1951). These tissues were taken from three different regions of the early embryos, and from eight different regions of the older ones, and were derived mainly from the lower layer. Epiblast tissues were also used. The experiments were designed to test the ability of one tissue to penetrate another. A single tissue was grown in culture in a Falcon dish for 18–24 h until it had formed a coherent sheet of cells (Explant I). A second tissue was then combined with it in one of two ways: A small piece of tissue (Explant II) was explanted on top of Explant I. In most cases Explant II penetrated through Explant I and spread on the Falcon dish. Another small piece of tissue (Explant III) was explanted beside (in confrontation with) Explant I. Usually, Explant III penetrated into Explant 1 rather than vice versa. The results were analysed to see if there were any variations in behaviour of the different tissues. The main result was that important differences were found to exist between certain types of chick and quail cells when grown in culture; the implications of this finding for the widely used technique of xenoplastic grafting are mentioned. Another result was that Explant I was more likely to be penetrated when the second tissue was placed on top of it (Explant II) than when it was confronted with it (Explant III). The significance of these results is discussed.

A pattern of circular islands of adhesive substratum can be used to control cell shape and behaviour. We have shown previously that the proportion of Swiss 3T3 cells that synthesize DNA varies with the area of the island to which they are attached, within the range 500–5000 μm2. In this paper we investigate the cytoskeleton and adhesions of cells on islands using a variety of techniques including phalloidin staining and interference reflection microscopy. Islands of area 2000 μm2 or less constrain cell shape, and cause focal contacts and actin microfilament bundles to accumulate in a circle at the margin. These changes are most obvious in islands of about 1000 gm2, in which a complete ring of adhesion is sometimes formed in the periphery of the cell. This peripheral distribution is less common in cells on even smaller islands, and the focal contacts become smaller and less numerous. It is not yet clear whether any of these structural changes are associated directly with the proliferative stimulus due to contact with the substratum. However, we expect that the use of patterned substrata will contribute to the study of how cell shape and structure regulate many cell functions.

The stimulus to growth that occurs when cells attach to the substratum can be studied with small adhesive islands. Large numbers of these islands can be grouped together into arrays made up of various sizes, and the response of cells to incubation on these arrays allows the anchorage stimulus to be measured. Past work has shown that single isolated cells can be stimulated to proliferate under these circumstances quite as freely as they do in ordinary cultures, and that the maximum response is given by islands whose size is less than 5000 microns 2. This anchorage stimulus might be mediated by the cytoskeleton, which assembles rapidly around the points of attachment to the substratum. One possible approach to testing this hypothesis is to expose cells to islands of different shapes, and to search for common factors among the different arrangements of the cytoskeleton that these different islands cause. Circular islands induced a relatively disordered arrangement of actin fibres. The fibres were attached at one end to foci of vinculin, which sometimes became arranged in a ring around the margin of the island. Triangular islands showed a more orderly arrangement of actin, in three bands parallel to the sides. In this case, the vinculin accumulated at the apices. Long islands only 3 microns wide could also provide effective attachment for the cells. In this shape the actin accumulated in two bands 2 microns or more apart and up to 5 microns high, and the vinculin similarly collected in parallel interrupted bands along the margins of the island. The number of vinculin foci differed on these three different island shapes, and the total area of vinculin was more than three times greater on long islands than on circles or triangles of the same size. Despite these differences, all three different shapes of island were capable of inducing up to 100 microns 2 of vinculin foci in each cell. Round and triangular islands induced this maximum amount of vinculin when their size was 5000 microns 2. Linear islands induced the same amount when they were only 1000 microns 2. The effect of different shapes on total vinculin focal area was paralleled by their effects on growth. All three shapes could support a similar amount of proliferation. Round and triangular islands induced the maximum amount of proliferation when they were 5000 microns 2 in area, and linear islands when they were only 1000 microns 2.(ABSTRACT TRUNCATED AT 400 WORDS)

Commercial 'Williams' banana plantations were surveyed at random on the North Coast of New South Wales during July 1990 and 1991, to determine spraying practices for leaf disease control and their efficacy in relation to leaf retention at harvest. A climatic index (CIP), based on temperature and wetness, indicated environmental conditions were conducive to leaf diseases caused by Mycosphaerella musicola and M. musae over summer and autumn 1990 but were less conducive in 1991, especially in autumn. In 1990, 5 of 44 plantations surveyed on the Mid North Coast (MNC) received no fungicide sprays; the remainder received 1-5 sprays of petroleum oil or oil mixed with propiconazole (mean 3.0 1.3) in December-May. Two plantations were sprayed using misting machines, the other 37 were aerially sprayed. The average numbers of leaves remaining on plants with mature bunches ranged from 0.3 to 8.3 (mean 4.7 2.2). A spray frequency model indicated that leaves per plant at harvest in July increased with numbers of sprays applied and decreased with increasing damage from wind and frost (r2 = 0.49; d.f. = 40; P<0.01). Another model based on the accumulated CIP from October to July (+CIP), adjusted for the timing and fungicidal effects of each spray, indicated that leaves per plant at harvest decreased with increasing +CIP, and wind and frost damage (r2 = 0.53; d.f. = 40; P<0.01). In 1991,4 of 38 plantations on the MNC and 3 of 32 on the Far North Coast (FNC) received no sprays; the remainder received 1-9 sprays of oil, oil + propiconazole, or oil + protectant fungicide mixtures. Fewer sprays were applied on the MNC in 1991 than 1990, but the timing of sprays remained unchanged. More sprays were applied on the FNC than MNC in 1991, and sprays were applied from December to July. Leaves per plant varied from 4.2 to 12.1 (mean 8.3 2.0). The spray frequency model from 1990 predicted leaves per plant in 1991 poorly (r2 = 0.17; d.f. = 68; P<0.01) and with substantial bias, whereas, the CIP model predicted leaves per plant for the MNC and FNC well (r2 = 0.41; d.f. = 68; P<0.01) and without bias. Observations in 1991 on the 70 surveyed plantations indicated that leaf retention also decreased with increasing damage by burrowing nematode (Radopholus similis) and banana weevil borer (Cosmopolites sordidus), increasing latitude of the plantation, and decreasing electrical conductivity of the soil solution. These variables accounted for a further 21% of the variation in leaves per plant observed in 1991. Leaf retention was not significantly (P>0.05) related to soil pH or to spraying method (aerial v. ground).

Samples taken by a Casella personal respirable dust sampler in a cloud of pure quartz dust in the laboratory dust chamber were examined by x-ray diffraction using molybdenum and copper Kα radiations with step scanning. A calibration of this system was obtained with respirable dust quantities on the filter of 0.04 to 3 mg. There was a decrease in the factors relating peak height or peak area to mass of quartz at low quantities of quartz, presumably due partly to penetration into the rather coarse (5-µm pore size) silver membrane used and to shadowing by the roughness of the silver membrane. Calibrations were also performed with samples prepared by Leroux's technique of elutriation and collection on a filter. These resulted in x-ray intensities 25% lower than those of the samples prepared in the dust chamber. This technique was tested in some Ontario hard rock mines and in Nova Scotia coal mines. The technique is sensitive enough to detect respirable quartz dust concentrations of 0.01 mg/m3 on shift period samples. However, interference from mica has been found in a number of samples.