Changes in serum immunoglobulins in subjects with acute myocardial infarct and essential hypertension

20 (12 men and 8 women) acute myocardial infarction (AMI) patients and 17 (14 men and 3 women) patients with arterial hypertension (II degrees stage according to OMS) in comparison to controls age and sex matched, were studied, serum IgA, IgG, IgM were evaluated with radial immunodiffusion and serum IgE with RIA. Ho significant changes ef immunoglobulins were observed between hypertensive patients and controls; whereas a significant increase of IgM, IgG and IgE, with out changes of IgA, were shown in AMI patients. Serum Ig and IgM were significantly augmented in AMI patients in comparison to hypertensive patients.     

Shp2 regulates SRC family kinase activity and Ras/Erk activation by controlling Csk recruitment

The protein-tyrosine phosphatase Shp2 plays an essential role in growth factor and integrin signaling, and Shp2 mutations cause developmental defects and/or malignancy. Previous work has placed Shp2 upstream of Ras. However, the mechanism of Shp2 action and its substrate(s) are poorly defined. Additional Shp2 functions downstream of, or parallel to, Ras/Erk activation also are proposed. Here, we show that Shp2 promotes Src family kinase (SFK) activation by regulating the phosphorylation of the Csk regulator PAG/Cbp, thereby controlling Csk access to SFKs. In Shp2-deficient cells, SFK inhibitory C-terminal tyrosines are hyperphosphorylated, and the tyrosyl phosphorylation of multiple SFK substrates, including Plcgamma1, is decreased. Decreased Plcgamma1 phosphorylation leads to defective Ras activation on endomembranes, and may help account for impaired Erk activation in Shp2-deficient cells. Decreased phosphorylation/activation of other SFK substrates may explain additional consequences of Shp2 deficiency, including altered cell spreading, stress fibers, focal adhesions, and motility.     

Industrial microbiology of solar salt production

Solar salterns can be modeled as giant outdoor chemostats, much like a series of dams on a slow-moving river. Microorganisms and their products play an essential, but sometimes uncharacterized, role in salt production in these ponds, from seawater salinity up through NaCl saturation. They may physically affect the evaporation process and their by-products may chemically modify or bind with dissolved ions. Many solar salt facilities engage microbiologists to establish monitoring programs for analyses of nutrients, standing crop and associated biological variables in the ponds. Other solar salt companies engage microbiologists only when there are “crises” in the ponds that interfere with salt production. Journal of Industrial Microbiology & Biotechnology (2002) 28, 42–47 DOI: 10.1038/sj/jim/7000173 Received 20 May 2001/ Accepted in revised form 13 June 2001     

Rapid and unexpected effects of piscivore introduction on trophic position and diet of perch (Perca flavescens) in lakes recovering from acidification and metal contamination

1. Yellow perch (Perca flavescens) are often the only surviving fish species in acidified lakes. We studied four lakes along a gradient of recovery from acidification and that had different food web complexities. All had abundant yellow perch, two had low piscivore abundance, one had a well‐established piscivore population and one was manipulated by introducing piscivorous smallmouth bass (Micropterus dolomieu). We hypothesised that there would be strong effects on perch abundance, behaviour and diet induced by the presence of piscivores. 2. In the manipulated lake, the bass reduced yellow perch abundance by 75% over a 2‐year period. Concomitantly, perch use of the pelagic habitat fell from 48 to 40%. 3. In contrast to findings from less disturbed systems, yellow perch in the littoral zone of the manipulated lake did not strongly shift from zooplankton to benthic food sources after the arrival of piscivores. Diet analysis using stable carbon isotopes revealed a strong continued reliance on zooplankton in all lakes, independent of the degree of piscivory. The failure to switch to benthos in the refuge area of the littoral zone is most likely related to the depauperate benthos communities in these formerly acidified lakes. 4. Yellow perch in lakes recovering from acidification face a considerable ecological challenge as the necessary switch to benthic diet is hindered by a low abundance of benthos. The arrival of piscivores in these recovering lakes imposes further restrictions on perch access to food items. We infer that future recovery of perch populations (and higher trophic levels) will have to be preceded by the re‐establishment of diverse benthic macroinvertebrate communities in these lakes.     

Predation on Moose Calves by European Brown Bears

Abstract: In North America, brown bears (Ursus arctos) can be a significant predator on moose (Alces alces) calves. Our study in Sweden is the first in which brown bears are the only predator on moose calves. Bears and moose occurred at densities of about 30/1,000 km² and 920/1,000 km², respectively, and bears killed about 26% of the calves. Ninety-two percent of the predation took place when calves were <1 month old. Bear predation was probably additive to other natural mortality, which was about 10% in areas both with and without bears. Females that lost their calves in spring produced more calves the following year (1.54 calves/F) than females that kept their calves (1.11 calves/F), which reduced the net loss of calves due to predation to about 22%.     

Bronchoabsorption; a novel bronchoscopic technique to improve biomarker sampling of the airway

Background

Current techniques used to obtain lung samples have significant limitations and do not provide reproducible biomarkers of inflammation. We have developed a novel technique that allows multiple sampling methods from the same area (or multiple areas) of the lung under direct bronchoscopic vision. It allows collection of mucosal lining fluid and bronchial brushing from the same site; biopsy samples may also be taken. The novel technique takes the same time as standard procedures and can be conducted safely.

Methods

Eight healthy smokers aged 40–65 years were included in this study. An absorptive filter paper was applied to the bronchial mucosa under direct vision using standard bronchoscopic techniques. Further samples were obtained from the same site using bronchial brushings. Bronchoalveolar lavage (BAL) was obtained using standard techniques. Chemokine (C-C Motif) Ligand 20 (CCL20), CCL4, CCL5, Chemokine (C-X-C Motif) Ligand 1 (CXCL1), CXCL8, CXCL9, CXCL10, CXCL11, Interleukin 1 beta (IL-1β), IL-6, Vascular endothelial growth factor (VEGF), Matrix metalloproteinase 8 (MMP-8) and MMP-9 were measured in exudate and BAL. mRNA was collected from the bronchial brushings for gene expression analysis.

Results

A greater than 10 fold concentration of all the biomarkers was detected in lung exudate in comparison to BAL. High yield of good quality RNA with RNA integrity numbers (RIN) between 7.6 and 9.3 were extracted from the bronchial brushings. The subset of genes measured were reproducible across the samples and corresponded to the inflammatory markers measured in exudate and BAL.

Conclusions

The bronchoabsorption technique as described offers the ability to sample lung fluid direct from the site of interest without the dilution effects caused by BAL. Using this method we were able to successfully measure the concentrations of biomarkers present in the lungs as well as collect high yield mRNA samples for gene expression analysis from the same site. This technique demonstrates superior sensitivity to standard BAL for the measurement of biomarkers of inflammation. It could replace BAL as the method of choice for these measurements. This method provides a systems biology approach to studying the inflammatory markers of respiratory disease progression.

Trial registration

NHS Health Research Authority (13/LO/0256).     

Analysis of Ras and Rap activation in living cells using fluorescent Ras binding domains

Ras GTPases regulate cellular growth and differentiation and are modulated by myriad stimuli including growth factors, cytokines, antigens, and UV irradiation. Ras GTPases are molecular switches that are active when GTP-bound and inactive when GDP-bound. The ability of these GTPases to signal requires that the GTP-bound form engage downstream effectors, interactions that occur only on the cytosolic surface of cellular membranes. Ras family proteins include H-Ras, N-Ras, K-Ras, and Rap1. Insight into the regulation and signaling properties of these molecules has come largely from in vitro studies relying on cellular extracts prepared following cellular stimulation. Since Ras GTPases are expressed on multiple cellular compartments that include the plasma membrane, vesicles derived from the plasma membrane, and other internal membranes such as the ER and Golgi complex, analysis of how their spatial distribution modulates signaling has remained unknown. We have developed fluorescent, GFP-based probes capable of selectively binding GTP-bound Ras or Rap1 in living cells. We have used these reporters to examine sites of cellular activation of Ras and Rap1 during growth factor stimulation. These studies have revealed new insights into the platforms from which these GTPases signal and have led to the hypothesis that GTPase signaling is modulated in a compartmentalized fashion. Here, we describe the design and implementation of fluorescent probes for Ras and Rap1.     

Rap1 up-regulation and activation on plasma membrane regulates T cell adhesion

Rap1 and Ras are closely related GTPases that share some effectors but have distinct functions. We studied the subcellular localization of Rap1 and its sites of activation in living cells. Both GFP-tagged Rap1 and endogenous Rap1 were localized to the plasma membrane (PM) and endosomes. The PM association of GFP-Rap1 was dependent on GTP binding, and GFP-Rap1 was rapidly up-regulated on this compartment in response to mitogens, a process blocked by inhibitors of endosome recycling. A novel fluorescent probe for GTP-bound Rap1 revealed that this GTPase was transiently activated only on the PM of both fibroblasts and T cells. Activation on the PM was blocked by inhibitors of endosome recycling. Moreover, inhibition of endosome recycling blocked the ability of Rap1 to promote integrin-mediated adhesion of T cells. Thus, unlike Ras, the membrane localizations of Rap1 are dynamically regulated, and the PM is the principle platform from which Rap1 signaling emanates. These observations may explain some of the biological differences between these GTPases.