Impaired autophagic flux mediates acinar cell vacuole formation and trypsinogen activation in rodent models of acute pancreatitis

The pathogenic mechanisms underlying acute pancreatitis are not clear. Two key pathologic acinar cell responses of this disease are vacuole accumulation and trypsinogen activation. We show here that both result from defective autophagy, by comparing the autophagic responses in rodent models of acute pancreatitis to physiologic autophagy triggered by fasting. Pancreatitis-induced vacuoles in acinar cells were greater in number and much larger than those induced with fasting. Degradation of long-lived proteins, a measure of autophagic efficiency, was markedly inhibited in in vitro pancreatitis, while it was stimulated by acinar cell starvation. Further, processing of the lysosomal proteases cathepsin L (CatL) and CatB into their fully active, mature forms was reduced in pancreatitis, as were their activities in the lysosome-enriched subcellular fraction. These findings indicate that autophagy is retarded in pancreatitis due to deficient lysosomal degradation caused by impaired cathepsin processing. Trypsinogen activation occurred in pancreatitis but not with fasting and was prevented by inhibiting autophagy. A marker of trypsinogen activation partially localized to autophagic vacuoles, and pharmacologic inhibition of CatL increased the amount of active trypsin in acinar cells. The results suggest that retarded autophagy is associated with an imbalance between CatL, which degrades trypsinogen and trypsin, and CatB, which converts trypsinogen into trypsin, resulting in intra-acinar accumulation of active trypsin in pancreatitis. Thus, deficient lysosomal degradation may be a dominant mechanism for increased intra-acinar trypsin in pancreatitis.

Larvicidal effect of imidacloprid/moxidectin spot-on solution in dogs experimentally inoculated with Angiostrongylus vasorum

A controlled, randomized, blinded dose confirmation study was conducted to evaluate the larvicidal efficacy and safety of imidacloprid 10 mg/kg/moxidectin 2.5 mg/kg body weight spot-on solution in dogs experimentally inoculated with 200 infective third stage larvae (L3) of Angiostrongylus vasorum. Twenty-four adult dogs were randomly allocated to three study groups of 8 dogs each. Animals in group 1 were treated 4 days post-inoculation (dpi), those in group 2 at 32 dpi, and the dogs in group 3 were left untreated. All dogs were euthanized and necropsied 56-59 dpi. In order to determine the worm burdens in the arterial lung vessels a method of reverse lung perfusion with phosphate buffered solution after inhibition of coagulation with heparin was applied. In the control group, excretion of first stage larvae (L1) of A. vasorum started 47-55 dpi and all dogs excreted L1 at least on one sample day before euthanasia (0.1-32.5 larvae per gram of faeces). A mean of 99 (SD 42.8) adult parasites were recovered in the post-mortem examinations in these eight control dogs. In contrast, no L1 at all were found in the faeces of dogs of groups 1 and 2, nor were any adult parasites detected at necropsy. Respiratory symptoms were observed in dogs of groups 2 and 3. Pathological findings in the lungs correlated with the treatment groups: in the animals of group 1, no or minimal lesions were found, while in all those of group 2 dispersed patterns of pale pink, slightly raised and consolidated foci were present in all lung lobes. In contrast, the lungs of the dogs from group 3 were severely affected: large confluent areas were hardened, raised and discoloured, with frequent haemorrhagic patches. Pneumonia, thrombi and parasites were histologically confirmed. The lung lymph nodes were regularly enlarged. Hence, imidacloprid/moxidectin spot-on effectively eliminated fourth stage larvae (L4) and immature adult A. vasorum in experimentally infected dogs and prevented patent infections. The earlier an infected dog was treated, the less severe were the pathological lesions observed in the lungs.

The burden of smoking-related ill health in the UK

BACKGROUND

Smoking is one of the biggest avoidable causes of morbidity and mortality in the United Kingdom. This paper quantifies the current health and economic burden of smoking in the UK. It provides comparisons with previous studies of the burden of smoking in the UK and with the costs for other chronic disease risk factors.

METHODS

A systematic literature review to identify previous estimates of National Health Service costs attributable to smoking was undertaken. Information from the World Health Organization's Global Burden of Disease Project and routinely collected mortality data were used to calculate mortality due to smoking in the UK. Population-attributable fractions for smoking-related diseases from the Global Burden of Disease Project were applied to NHS cost data to estimate direct financial costs.

RESULTS

Previous studies estimated that smoking costs the NHS about 1.4 billion to 1.7 billion pound in 1991 and has been responsible for about 100,000 deaths per annum over the past 10 years. This paper estimates that the number of deaths attributable to smoking in 2005 was 109,164 (19% of all deaths, 27% deaths in men and 11% of deaths in women). Smoking was directly responsible for 12% of disability adjusted life years lost in 2002 (15.4% in men; 8.5% in women) and the direct cost to the NHS was 5.2 billion pound in 2005-6.

CONCLUSION

Smoking is still a considerable public health burden in the UK. Accurately establishing the burden in terms of death, disability and financial costs is important for informing national public health policy.

An Australian survey of the procedures used for the treatment of opiate users

Drug and alcohol agencies across Australia were asked to describe the services they offer to opiate users. Of the 284 agencies identified as providing treatment, 229 (81%) responded. A standard assessment procedure was used in 72% of agencies. Eighty (35%) agencies offered detoxification and had assisted 7883 clients with detoxification in the 12 months prior to March 1990. Methadone maintenance was offered in 20% of agencies with 5234 clients currently receiving this treatment. Daily doses of methadone in the range of 40-80 mg were described for most (51%) clients receiving methadone and concurrent counselling was provided in 45% of cases. Standard psychosocial interventions were provided by 60% of agencies. Out-patient or non-residential settings were most common (36%), with residential therapeutic communities being the setting for 21% of programmes. Supportive counselling was the most commonly used individual approach, and cognitive-behavioural or 12-step approaches were the most commonly used group approaches. Brief support or referral to Nar-Anon were the most popular family interventions. Procedures aimed at reducing the risk of HIV were in place at 85% of agencies. These findings are discussed in light of research evidence. Briefly, there is a diversity of treatment options available from different treatment agencies which is not reflected within the agencies, little aftercare is offered despite high rates of relapse, and doses of methadone are lower than has been found to be optimal.

Characteristics of clients receiving treatment in Australian drug and alcohol agencies: a national census

The first Australian national census of clients of drug and alcohol treatment agencies was undertaken to document the characteristics of clients attending these facilities. Of the agencies surveyed nationwide, 431 (85.2%) completed and returned census forms describing demographic and drug use details of their clients. A total of 6175 clients were reported to have received services (beyond methadone maintenance alone) in the responding agencies on the census day. Ninety percent of the clients seen were substance users, and 10% of clients were relatives or friends of a substance user. The mean age of the clients was 34 years and two-thirds were male. The majority were Australian born, with 10% described as Aborigines or Torres Strait Islanders. The majority of the clients were not in paid employment. Fifty-five percent of all clients received treatments services on a non-residential basis. The most frequent presenting drug problem reported was alcohol, followed by opiates and tobacco. Thirty-three percent of the substance users were reported to have injected illicit drugs in the past 12 months.

Characterization of structures in biofilms formed by a Pseudomonas fluorescens isolated from soil

Background

Microbial biofilms represent an incompletely understood, but fundamental mode of bacterial growth. These sessile communities typically consist of stratified, morphologically-distinct layers of extracellular material, where numerous metabolic processes occur simultaneously in close proximity. Limited reports on environmental isolates have revealed highly ordered, three-dimensional organization of the extracellular matrix, which may hold important implications for biofilm physiology in vivo.

Results

A Pseudomonas spp. isolated from a natural soil environment produced flocculent, nonmucoidal biofilms in vitro with unique structural features. These mature biofilms were made up of numerous viable bacteria, even after extended culture, and contained up to 50% of proteins and accumulated 3% (by dry weight) calcium, suggesting an important role for the divalent metal in biofilm formation. Ultrastructurally, the mature biofilms contained structural motifs consisting of dense, fibrillary clusters, nanofibers, and ordered, honeycomb-like chambers enveloped in thin sheets.

Conclusion

Mature biofilms contained living bacteria and were structurally, chemically, and physiologically heterogeneous. The principal architectural elements observed by electron microscopy may represent useful morphological clues for identifying bacterial biofilms in vivo. The complexity and reproducibility of the structural motifs observed in bacterial biofilms appear to be the result of organized assembly, suggesting that this environmental isolate may possess ecological advantages in its natural habitat.

Knockdown of p180 eliminates the terminal differentiation of a secretory cell line

We have previously reported that the expression in yeast of an integral membrane protein (p180) of the endoplasmic reticulum (ER), isolated for its ability to mediate ribosome binding, is capable of inducing new membrane biogenesis and an increase in secretory capacity. To demonstrate that p180 is necessary and sufficient for terminal differentiation and acquisition of a secretory phenotype in mammalian cells, we studied the differentiation of a secretory cell line where p180 levels had been significantly reduced using RNAi technology and by transiently expressing p180 in nonsecretory cells. A human monocytic (THP-1) cell line, that can acquire macrophage-like properties, failed to proliferate rough ER when p180 levels were lowered. The Golgi compartment and the secretion of apolipoprotein E (Apo E) were dramatically affected in cells expressing reduced p180 levels. On the other hand, expression of p180 in a human embryonic kidney nonsecretory cell line (HEK293) showed a significant increase in proliferation of rough ER membranes and Golgi complexes. The results obtained from knockdown and overexpression experiments demonstrate that p180 is both necessary and sufficient to induce a secretory phenotype in mammalian cells. These findings support a central role for p180 in the terminal differentiation of secretory cells and tissues.

Guidelines for the use and interpretation of assays for monitoring autophagy in higher eukaryotes

Research in autophagy continues to accelerate,(1) and as a result many new scientists are entering the field. Accordingly, it is important to establish a standard set of criteria for monitoring macroautophagy in different organisms. Recent reviews have described the range of assays that have been used for this purpose.(2,3) There are many useful and convenient methods that can be used to monitor macroautophagy in yeast, but relatively few in other model systems, and there is much confusion regarding acceptable methods to measure macroautophagy in higher eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers of autophagosomes versus those that measure flux through the autophagy pathway; thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from fully functional autophagy that includes delivery to, and degradation within, lysosomes (in most higher eukaryotes) or the vacuole (in plants and fungi). Here, we present a set of guidelines for the selection and interpretation of the methods that can be used by investigators who are attempting to examine macroautophagy and related processes, as well as by reviewers who need to provide realistic and reasonable critiques of papers that investigate these processes. This set of guidelines is not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to verify an autophagic response.

Detection of a microbial biofilm in intraamniotic infection

OBJECTIVE

Microbial biofilms are communities of sessile microorganisms formed by cells that are attached irreversibly to a substratum or interface or to each other and embedded in a hydrated matrix of extracellular polymeric substances. Microbial biofilms have been implicated in >80% of human infections such as periodontitis, urethritis, endocarditis, and device-associated infections. Thus far, intraamniotic infection has been attributed to planktonic (free-floating) bacteria. A case is presented in which "amniotic fluid sludge" was found to contain microbial biofilms. This represents the first report of a microbial biofilm in the amniotic cavity.

STUDY DESIGN

"Amniotic fluid sludge" was detected by transvaginal sonography and retrieved by transvaginal amniotomy. Bacteria were identified with scanning electron microscopy and fluorescence in situ hybridization for conserved regions of the microbial genome; the exopolymeric matrix was identified by histochemistry by the wheat germ agglutinin lectin method. The structure of the biofilm was imaged with confocal laser scanning microscopy.

RESULTS

"Amniotic fluid sludge" was imaged with scanning electron microscopy, which allowed the identification of bacteria embedded in an amorphous material and inflammatory cells. Bacteria were demonstrated with fluorescent in situ hybridization using a eubacteria probe. Extracellular matrix was identified with the wheat germ agglutinin lectin stain. Confocal microscopy allowed 3-dimensional visualization of the microbial biofilm.

CONCLUSION

Microbial biofilms have been identified in a case of intraamniotic infection with "amniotic fluid sludge."

Possible role of biofilm in fulminant meningitis related to cochlear implantation of dysplastic inner ear

Thanks to improvements in device design and surgical procedures, the number of potential candidates for cochlear implantation has been growing to include patients with inner ear malformations. Many precautions are taken pre-, peri- and postoperatively for these patients given the increased risk of surgical and medical complications, but with the rising bacterial resistance to antibiotics and the discovery of biofilm as a probable cause of chronic infections, postoperative morbidity remains higher than desired.

OBJECTIVE

The purpose of this investigation is to describe histological findings on a temporal bone from a 2-year-old infant with a cochlear implant and an inner ear deformity who died of bacterial meningitis.

MATERIALS AND METHODS

The patient's temporal bone was studied under light microscopy, the cochlear implant studied with a scanning electron microscope, and later subjected to in situ hybridization to find bacterial DNA.

RESULTS

The scanning electron microscopy image shows cellular formations on the surface of the implant, which later binds to the probe used for the in situ hybridization.

CONCLUSION

There is evidence that bacterial DNA is present on the electrode array, which suggests existence of biofilm formation on the cochlear implant surface.