A preliminary report on a bacteriological assay for compound 1080 (sodium monofluoroacetate)

A new, inexpensive, simple and rapid bioassay for sodium monofluoroacetate (compound 1080) was developed using bacteria. Two 1080-sensitive isolates ( Bacillus sp. DHW and Acinetobacter sp. DHW) from local aquatic environments were tested on different agar media using the disc diffusion technique. Both bacteria exhibited zones of growth inhibition surrounding the 1080 discs that were linearly proportional to the concentrations (log₁₀) of 1080. Preliminary studies indicate that this technique can be used for assaying 1080 in environmental and biological samples.     

The extent of the two tier service for fundholders.

OBJECTIVE--To examine possible differential changes in outpatient referrals to orthopaedic clinics, attendances, and waiting times between fundholding and non-fundholding general practitioners. DESIGN--Observational controlled study of referrals by general practitioners to orthopaedic outpatients between April 1991 and March 1995. SETTING--District health authority in south-west England. SUBJECTS--10 fundholding practices with 108,300 registered patients; 22 control practices with 159,900 registered patients. MAIN OUTCOME MEASURES--Changes in age standardised referral and outpatient attendance ratios for the year before and the two years after achieving fundholder status; changes in outpatient waiting times. RESULTS--In the year before achieving fundholding status both groups were referring more patients than were being seen. Two years later, referral and attendance ratios had increased by 13% and 36% respectively for fundholders and 32% and 59% for controls, and both groups were referring fewer patients than were being seen. Attendances represented 112% of referrals for fundholders and 104% for controls. In 1991-2, a similar proportion of patients in the two groups was seen within three months of referral. The two hospitals that set up specific clinics exclusively for fundholders showed faster access for patients of fundholders by 1993-4, as did a third hospital without such clinics by 1994-5. CONCLUSIONS--Fundholders increased their orthopaedic referrals less than did controls and achieved a better balance between outpatient appointments and referrals. Their patients were likely to be seen more quickly, particularly if the hospital provided special clinics exclusively for fundholders. Lack of case mix information makes it impossible to judge whether these differences benefit or disadvantage patients.     

Leptin activation of mTOR pathway in intestinal epithelial cell triggers lipid droplet formation,cytokine production and increased cell proliferation

Accumulating evidence suggests that obesity and enhanced inflammatory reactions are predisposing conditions for developing colon cancer. Obesity is associated with high levels of circulating leptin. Leptin is an adipocytokine that is secreted by adipose tissue and modulates immune response and inflammation. Lipid droplets (LD) are organelles involved in lipid metabolism and production of inflammatory mediators, and increased numbers of LD were observed in human colon cancer. Leptin induces the formation of LD in macrophages in a PI3K/mTOR pathway-dependent manner. Moreover, the mTOR is a serine/threonine kinase that plays a key role in cellular growth and is frequently altered in tumors. We therefore investigated the role of leptin in the modulation of mTOR pathway and regulation of lipid metabolism and inflammatory phenotype in intestinal epithelial cells (IEC-6 cells). We show that leptin promotes a dose- and time-dependent enhancement of LD formation. The biogenesis of LD was accompanied by enhanced CXCL1/CINC-1, CCL2/MCP-1 and TGF-β production and increased COX-2 expression in these cells. We demonstrated that leptin-induced increased phosphorylation of STAT3 and AKT and a dose and time-dependent mTORC activation with enhanced phosphorilation of the downstream protein P70S6K protein. Pre-treatment with rapamycin significantly inhibited leptin effects in LD formation, COX-2 and TGF-β production in IEC-6 cells. Moreover, leptin was able to stimulate the proliferation of epithelial cells on a mTOR-dependent manner. We conclude that leptin regulates lipid metabolism, cytokine production and proliferation of intestinal cells through a mechanism largely dependent on activation of the mTOR pathway, thus suggesting that leptin-induced mTOR activation may contribute to the obesity-related enhanced susceptibility to colon carcinoma.     

Mitochondrial impairment observed in fibroblasts from South African Parkinson’s disease patients with parkin mutations

Parkinson’s disease (PD), defined as a neurodegenerative disorder, is characterized by the loss of dopaminergic neurons in the substantia nigra in the midbrain. Loss-of-function mutations in the parkin gene are a major cause of autosomal recessive, early-onset PD. Parkin has been implicated in the maintenance of healthy mitochondria, although previous studies show conflicting findings regarding mitochondrial abnormalities in fibroblasts from patients harboring parkin-null mutations. The aim of the present study was to determine whether South African PD patients with parkin mutations exhibit evidence for mitochondrial dysfunction. Fibroblasts were cultured from skin biopsies obtained from three patients with homozygous parkin-null mutations, two heterozygous mutation carriers and two wild-type controls. Muscle biopsies were obtained from two of the patients. The muscle fibers showed subtle abnormalities such as slightly swollen mitochondria in focal areas of the fibers and some folding of the sarcolemma. Although no differences in the degree of mitochondrial network branching were found in the fibroblasts, ultrastructural abnormalities were observed including the presence of electron-dense vacuoles. Moreover, decreased ATP levels which are consistent with mitochondrial dysfunction were observed in the patients’ fibroblasts compared to controls. Remarkably, these defects did not manifest in one patient, which may be due to possible compensatory mechanisms. These results suggest that parkin-null patients exhibit features of mitochondrial dysfunction. Involvement of mitochondria as a key role player in PD pathogenesis will have important implications for the design of new and more effective therapies.     

Cytokine profiles in the joint depend on pathology,but are different between synovial fluid,cartilage tissue and cultured chondrocytes

Introduction

This study aimed to evaluate whether profiles of several soluble mediators in synovial fluid and cartilage tissue are pathology-dependent and how their production is related to in vitro tissue formation by chondrocytes from diseased and healthy tissue.

Methods

Samples were obtained from donors without joint pathology (n = 39), with focal defects (n = 65) and osteoarthritis (n = 61). A multiplex bead assay (Luminex) was performed measuring up to 21 cytokines: Interleukin (IL)-1α, IL-1β, IL-1RA, IL-4, IL-6, IL-6Rα, IL-7, IL-8, IL-10, IL-13, tumor necrosis factor (TNF)α, Interferon (IFN)γ, oncostatin M (OSM), leukemia inhibitory factor (LIF), adiponectin, leptin, monocyte chemotactic factor (MCP)1, RANTES, basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), vascular growth factor (VEGF).

Results

In synovial fluid of patients with cartilage pathology, IL-6, IL-13, IFNγ and OSM levels were higher than in donors without joint pathology (P ≤0.001). IL-13, IFNγ and OSM were also different between donors with cartilage defects and OA (P <0.05). In cartilage tissue from debrided defects, VEGF was higher than in non-pathological or osteoarthritic joints (P ≤0.001). IL-1α, IL-6, TNFα and OSM concentrations (in ng/ml) were markedly higher in cartilage tissue than in synovial fluid (P <0.01). Culture of chondrocytes generally led to a massive induction of most cytokines (P <0.001). Although the release of inflammatory cytokines was also here dependent on the pathological condition (P <0.001) the actual profiles were different from tissue or synovial fluid and between non-expanded and expanded chondrocytes. Cartilage formation was lower by healthy unexpanded chondrocytes than by osteoarthritic or defect chondrocytes.

Conclusions

Several pro-inflammatory, pro-angiogenic and pro-repair cytokines were elevated in joints with symptomatic cartilage defects and/or osteoarthritis, although different cytokines were elevated in synovial fluid compared to tissue or cells. Hence a clear molecular profile was evident dependent on disease status of the joint, which however changed in composition depending on the biological sample analysed. These alterations did not affect in vitro tissue formation with these chondrocytes, as this was at least as effective or even better compared to healthy chondrocytes.     

Evolutionary conservation of the chromosomal configuration and regulation of amylase genes among eight species of the Drosophila melanogaster species subgroup

Nuclear DNA was extracted from each of the eight species comprising the Drosophila melanogaster species subgroup. Southern hybridization of this DNA by using a molecular probe specific for the alpha-amylase coding region showed that the duplicated structure of the amylase locus, first found in D. melanogaster, is conserved among all species of the melanogaster subgroup. Evidence is also presented for the concerted evolution of the duplicated genes within each species. In addition, it is shown that the glucose repression of amylase gene expression, which has been extensively studied in D. melanogaster, is not confined to this species but occurs in all eight members of the species subgroup. Thus, both the duplicated gene structure and the glucose repression of Drosophila amylase gene activity are stable over extended periods of evolutionary time.