Actin organization and fibrin-clot retractile activity of cultured mouse fibroblasts

Summary It is known that human and animal fibroblasts are able to induce the retraction of a fibrin clot. In the present study the correlation between (i) fibrinclot retractile (FCR) activity, (ii) the number of actin stress-lines in mouse fibroblasts during growth in culture, and (iii) the sensitivity of actin stress-lines to a powerful actin-depolymerizing factor (ADF), present in plasma and serum of humans and laboratory animals was investigated. Fibroblasts at early passages (2–4) were tested for these parameters at various intervals after seeding (24, 96, and 168 h). The number of actin stress-lines was progressively higher, while the sensitivity to ADF action was progressively lower in cells cultured from 24 to 168 h; the FCR capacity was significantly decreased at 168 h. These data suggest that cells containing weakly polymerized and/or stabilized actin are more active than those containing highly polymerized and/or stabilized actin in triggering fibroblast contraction.     

Differential stimulation of pancreatic-polypeptide and gastrin secretion by bombesin in man

Bombesin, besides many other actions on the mammalian gastroentero-pancreatic tract, strongly stimulates the release of pancreatic-polypeptide (PP) in dogs. In 8 healthy human volunteers (5 males, 3 females), the PP response during bombesin infusion was low (25.7 ± 6.3 peak vs. 5.0 ± 2.0 basal pmol/1) compared to the effect of a protein meal (144.1 ± 13.4 pmol/1) or to the gastrin response to the same dose of the amphibian polypeptide (140.0 ± 23.6 pmol/1 eq SHG 17 I). The response pattern of PP and gastrin was different as PP concentrations peaked 10 min after cessation of bombesin infusion (32.0 ± 4.9 pmol/1) when gastrin concentrations already were down to one third of the maximal response. Atropine inhibited the PP response to bombesin but did not abolish it completely. It is concluded that in man, the total effect of bombesin on PP secretion is minor compared both to the effect of the peptide on gastrin secretion in man and to the effect of bombesin in dogs. It is suggested that bombesin might have a dual, inhibitory-stimulatory, effect on PP secretion in man.     

Immunoreactivity for substance P in the gasserian ganglion, ophthalmic nerve and anterior segment of the rabbit eye

Summary The distribution of substance P (SP) immunofluorescence was investigated in the Gasserian ganglion, ophthalmic nerve and in the anterior segment of the rabbit eye. About one third of the nerve cell bodies in the Gasserian ganglion exhibited SP immunofluorescence, which was also observed in some nerve fibres of the ophthalmic nerve. In the cornea, some SP-positive iris contained numerous nerve fibres with SP immunofluorescence. In the sphincter area such fibres were circular, while the orientation of the SP fibres was radial in the dilator muscle. Both in the iris and in the ciliary body, the largest vessels were surrounded by nerves exhibiting SP immunofluorescence. A few nerve fibres also appeared in the stroma of the ciliary processes.     

Complex and simple sequences in human repeated DNAs

Highly repeated human DNA sequences were isolated by isopycnic centrifugation, or were eluted from gels after restriction enzyme cleavage. High molecular weight DNA peaks separable from the bulk of the DNA in a variety of gradients were shown to consist of very simple sequences characteristic of simple satellite DNAs; DNA fingerprint studies indicated each of these peaks could consist of tandem repeats of a specific oligonucleotide sequence as low as 10 base pairs (bp) long. All the gradient peaks could be assigned to one of two sequence groups and several different buoyant density peaks revealed the same sequence. — Restriction fragment multimers did not share common sequences with the satellite DNAs as judged by hybridization data. They could not be separated by isopycnic centrifugation. Furthermore these highly repeated DNAs were more complex in sequence and more variable than the satellites. Even the smallest (50 bp) fragments by depurination and other direct sequencing methods were shown to be more complex than the high molecular weight satellite peaks. — The idea that subsets of repeated DNAs may be defined by sequence complexity, possibly with discrete or separable functions, is proposed.     

Effects of alkali salts on carbon and nitrogen mineralization of organic matter in soil

Summary In an incubation experiment the mineralization of gulmohur leaves (Delonix regia L.) added to soil was studied at increased levels of exchangeable sodium percentage (ESP). CO₂ evolution, total mineralization of carbon and humic/fulvic acid carbon ratio increased with increased ESP and the process of nitrification was inhibited completely between 70–92 ESP. The mineralization and losses of nitrogen were equal to control up to 70 ESP but were very high at 92 ESP. The extractable carbon varied from 26% in case of control to 31% at 48.6 ESP.     

Annulate lamellae in hindgut epithelial cells ofIsopoda

Summary Hindgut epithelial cells of the aquatic isopod,Asellus communis, and the terrestrial isopod,Armadillidium vulgare, possess annulate lamellae. The organelle is present in non-dividing cells of intermolt adult organisms. The lamellae exhibit dense pore areas traversed by diaphragms, and the lamellae are associated with elements of endoplasmic reticulum.This research was supported in part by a grant to E. R. Witkus from the Irene Heinz and John La Porte Given Foundation.     

Assessing the risk of resistance to cationic biocides incorporating realism-based and biophysical approaches

The control of microorganisms is a key objective in disease prevention and in medical, industrial, domestic, and food-production environments. Whilst the effectiveness of biocides in these contexts is well-evidenced, debate continues about the resistance risks associated with their use. This has driven an increased regulatory burden, which in turn could result in a reduction of both the deployment of current biocides and the development of new compounds and formulas. Efforts to balance risk and benefit are therefore of critical importance and should be underpinned by realistic methods and a multi-disciplinary approach, and through objective and critical analyses of the literature. The current literature on this topic can be difficult to navigate. Much of the evidence for potential issues of resistance generation by biocides is based on either correlation analysis of isolated bacteria, where reports of treatment failure are generally uncommon, or laboratory studies that do not necessarily represent real biocide applications. This is complicated by inconsistencies in the definition of the term resistance. Similar uncertainties also apply to cross-resistance between biocides and antibiotics. Risk assessment studies that can better inform practice are required. The resulting knowledge can be utilised by multiple stakeholders including those tasked with new product development, regulatory authorities, clinical practitioners, and the public. This review considers current evidence for resistance and cross-resistance and outlines efforts to increase realism in risk assessment. This is done in the background of the discussion of the mode of application of biocides and the demonstrable benefits as well as the potential risks.