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1.
Int J Tuberc Lung Dis ; 24(1): 28-35, 2020 01 01.
Article in English | MEDLINE | ID: mdl-32005304

ABSTRACT

SETTING: Access to information about tuberculosis (TB) is vital to ensure timely diagnosis, treatment, and control among vulnerable communities. Improved approaches for distributing health education materials to remote populations are needed.OBJECTIVE: To evaluate the impact of two comprehensive video training curricula in improving patient, community member, and community health worker knowledge of TB in a remote area of Madagascar.DESIGN: A pre-test/post-test design was used to measure knowledge acquisition. Educational videos were short, culturally appropriate films presented at critical moments in the TB cascade of care.RESULTS: Of the total 146 participants, 86 (58.9%) improved their score on the post-test, 50 (34.2%) obtained the same score, and 10 (6.8%) received a worse score. A statistically significant difference was observed between the pre- and post-test scores, wherein scores increased by a median of 10.0% (interquartile range 0.0-20.0) after viewing the videos (P < 0.001). There was a significant difference between the number of correct answers on the pre-test and the number of correct answers on the post-test (P < 0.001).CONCLUSION: Educational videos were found to significantly improve TB knowledge among a low-literacy, remote population in Madagascar. Our findings suggest educational videos could be a powerful, low-cost, and sustainable tool to improve access to TB education materials globally.


Subject(s)
Tuberculosis , Clinical Competence , Community Health Workers , Health Education , Humans , Madagascar , Tuberculosis/diagnosis , Tuberculosis/therapy
2.
Frontline Gastroenterol ; 7(2): 82-89, 2016 04.
Article in English | MEDLINE | ID: mdl-28840911

ABSTRACT

OBJECTIVE: Hepatocellular carcinoma (HCC), the sixth most common cancer worldwide and third most common cause of cancer related death, is closely associated with the presence of cirrhosis. Survival is determined by the stage of the cancer, with asymptomatic small tumours being more amenable to treatment. Early diagnosis is dependent on regular surveillance and the primary objective of this survey was to gain a better understanding of the baseline attitudes towards and provision of ultrasound surveillance (USS) HCC surveillance in the UK. In addition, information was obtained on the stages of cancer of the patients being referred to and discussed at regional multidisciplinary team meetings. DESIGN: UK hepatologists, gastroenterologists and nurse specialists were sent a questionnaire survey regarding the provision of USS for detection of HCC in their respective hospitals. RESULTS: Provision of surveillance was poor overall, with many hospitals lacking the necessary mechanisms to make abnormal results, if detected, known to referring clinicians. There was also a lack of standard data collection and in many hospitals basic information on the number of patients with cirrhosis and how many were developing HCC was not known. For the majority of new HCC cases was currently being made only at an incurable late stage (60%). CONCLUSIONS: In the UK, the current provision of USS based HCC surveillance is poor and needs to be upgraded urgently.

3.
Prev Vet Med ; 117(2): 403-12, 2014 Nov 15.
Article in English | MEDLINE | ID: mdl-25172121

ABSTRACT

A longitudinal field trial was carried out on a farm known to harbour cefotaximase (CTX-M)-positive Escherichia coli, in order to assess the impact of feeding waste milk containing antibiotic residues (WM+AR) on the prevalence of these bacteria in the faeces of calves. Fifty calves were alternately assigned to one of two groups at birth and fed either milk replacer (control group) or WM+AR (treatment group). Faecal samples were collected from all calves daily for the first week after enrolment, twice weekly until weaning, then weekly for a further six weeks. Environmental samples from the calf housing were collected weekly. WM+AR and powdered milk samples were examined for antibiotic residues and CTX-M-positive E. coli. Total E. coli and CTX-M-positive E. coli in faecal samples were enumerated using selective media. Regression analyses were performed on the bacterial count data using a population-averaged approach based on generalised estimating equations (GEE) to account for repeated measurements on individual calves over time. Cefquinome, a fourth generation cephalosporin, was detected in 87% of WM+AR samples at a mean concentration of 0.746 mg/l. All environmental sampling locations yielded CTX-M-positive E. coli. Significantly more pen floor samples were positive in the treatment group. Calves in the treatment group shed greater numbers of CTX-M-positive E. coli than calves in the control group throughout the study, and shedding decreased at a slower rate in the treatment group. CTX-M-positive E. coli persisted in a larger number of calves fed WM+AR compared with calves fed milk replacer where the prevalence in the treatment group declined significantly slower over time. There was no difference between calves fed WM+AR or calves fed milk replacer in the proportion of E. coli isolates that were CTX-M-positive. These findings indicate that feeding WM+AR increased the amount of resistant bacteria shed in the faeces. Shedding of CTX-M-positive E. coli persisted for longer in calves fed WM+AR, and persisted after weaning.


Subject(s)
Cattle Diseases/microbiology , Escherichia coli Infections/veterinary , Escherichia coli/isolation & purification , Milk/microbiology , beta-Lactamases/analysis , Animals , Animals, Newborn , Cattle , Colony Count, Microbial/veterinary , Escherichia coli/chemistry , Escherichia coli Infections/microbiology , Feces/microbiology , Female , Longitudinal Studies , Male , Milk/chemistry , Regression Analysis
4.
J Hepatol ; 61(1): 75-81, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24607626

ABSTRACT

BACKGROUND & AIMS: Subtle inter-patient genetic variation and environmental factors combine to determine disease progression in non-alcoholic fatty liver disease (NAFLD). Carriage of the PNPLA3 rs738409 c.444C >G minor allele (encoding the I148M variant) has been robustly associated with advanced NAFLD. Although most hepatocellular carcinoma (HCC) is related to chronic viral hepatitis or alcoholic liver disease, the incidence of NAFLD-related HCC is increasing. We examined whether rs738409 C >G was associated with HCC-risk in patients with NAFLD. METHODS: PNPLA3 rs738409 genotype was determined by allelic discrimination in 100 European Caucasians with NAFLD-related HCC and 275 controls with histologically characterised NAFLD. RESULTS: Genotype frequencies were significantly different between NAFLD-HCC cases (CC=28, CG=43, GG=29) and NAFLD-controls (CC=125, CG=117, GG=33) (p=0.0001). In multivariate analysis adjusted for age, gender, diabetes, BMI, and presence of cirrhosis, carriage of each copy of the rs738409 minor (G) allele conferred an additive risk for HCC (adjusted OR 2.26 [95% CI 1.23-4.14], p=0.0082), with GG homozygotes exhibiting a 5-fold [1.47-17.29], p=0.01 increased risk over CC. When compared to the UK general population (1958 British Birth Cohort, n=1476), the risk-effect was more pronounced (GC vs. CC: unadjusted OR 2.52 [1.55-4.10], p=0.0002; GG vs. CC: OR 12.19 [6.89-21.58], p<0.0001). CONCLUSIONS: Carriage of the PNPLA3 rs738409 C >G polymorphism is not only associated with greater risk of progressive steatohepatitis and fibrosis but also of HCC. If validated, these findings suggest that PNPLA3 genotyping has the potential to contribute to multi-factorial patient-risk stratification, identifying those to whom HCC surveillance may be targeted.


Subject(s)
Carcinoma, Hepatocellular/etiology , Carcinoma, Hepatocellular/genetics , Lipase/genetics , Liver Neoplasms/etiology , Liver Neoplasms/genetics , Membrane Proteins/genetics , Non-alcoholic Fatty Liver Disease/complications , Non-alcoholic Fatty Liver Disease/genetics , Polymorphism, Single Nucleotide , Adult , Aged , Case-Control Studies , Cohort Studies , Disease Progression , Female , Gene Frequency , Genetic Association Studies , Homozygote , Humans , Male , Middle Aged , Non-alcoholic Fatty Liver Disease/pathology , Risk Factors , White People/genetics
5.
Res Vet Sci ; 94(3): 419-24, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23360687

ABSTRACT

Enteric bacteria with resistance to third and fourth generation cephalosporin antibiotics, especially Escherichia coli bearing the blaCTX-M gene, have been detected in a wide range of food producing animals. However, commercial vaccines for these organisms are not currently available. An autogenous vaccine was prepared from E. coli bearing the blaCTX-M-14 gene and evaluated as a potential control measure to reduce shedding and dissemination of these organisms in cattle. Calves (n=30) received either an autogenous vaccine prepared from E. coli serotype O33 bearing the blaCTX-M-14 gene or a placebo by intramuscular injection on three separate occasions. Two weeks after the final vaccination, all calves were challenged by oral gavage with the O33 CTX-M-14 strain of E. coli (1×10(10) CFU). Faeces, intestinal mucosa and blood samples were taken for enumeration of total and CTX-M-14 E. coli and for assessment of the humoral immune response. The cumulative number of total E. coli excreted at 7 days post-challenge was significantly (p=0.006) lower in the vaccinated group than the placebo group. However, there was no significant difference in the shedding of either CTX-M-14 E. coli or total E. coli between vaccinated and placebo calves throughout the study period. The systemic immune response to E. coli O33 antigen was tested by ELISA and was significantly higher (p<0.001) in vaccinated than placebo calves. However, there was no significant difference in the mucosal immune response. These findings do not support the use of autogenous vaccination for the control of CTX-M-14 E. coli in calves.


Subject(s)
Autovaccines/therapeutic use , Cattle Diseases/prevention & control , Escherichia coli Infections/veterinary , Escherichia coli Vaccines/therapeutic use , Animals , Bacterial Shedding , Cattle , Cattle Diseases/immunology , Cattle Diseases/microbiology , Cephalosporin Resistance/genetics , Escherichia coli/genetics , Escherichia coli Infections/immunology , Escherichia coli Infections/microbiology , Escherichia coli Infections/prevention & control , Feces/microbiology , Plasmids/genetics
6.
J Oncol ; 2011: 215985, 2011.
Article in English | MEDLINE | ID: mdl-21547248

ABSTRACT

Aim. To examine interaction between history of cancer in first-degree relatives and tobacco smoking in index patients of pancreatic adenocarcinoma. Methods. We carried out a case-control involving 113 patients with pancreatic adenocarcinoma and 110 controls over a 12-month period at the Freeman Hospital, Newcastle upon Tyne, UK. They were all administered a detailed tobacco exposure questionnaire and a family history questionnaire. We calculated cumulative tobacco exposure and risk for pancreas cancer. Results. Both smokers (OR 3.01 (95% CI: 1.73 to 5.24)) and those with a family history of malignancy (OR 1.98 (95% CI: 1.15-3.38)) were more likely to develop pancreatic cancer. Having more than one first-degree relative with cancer did not significantly further increase the risk of pancreatic cancer. Amongst pancreatic cancer cases, cumulative tobacco exposure was significantly decreased (P = .032) in the group of smokers (current and ex-smokers) who had a family history of malignancy [mean (SD): 30.00 (24.77) pack-years versus 44.69 (28.47) pack-years with no such history]. Conclusions. Individuals with a family history of malignancy are at an increased risk of pancreatic cancer. Furthermore, individuals with a family history of malignancy and who smoke appear to require a lesser degree of tobacco exposure for the development of pancreatic cancer.

7.
Br J Surg ; 95(1): 22-32, 2008 Jan.
Article in English | MEDLINE | ID: mdl-18076020

ABSTRACT

BACKGROUND: The strongest risk factors for pancreatic adenocarcinoma are tobacco smoking and increasing age. However, only a few smokers or elderly individuals develop the disease and genetic factors are also likely to be important. METHODS: The literature on genetic factors modifying susceptibility to cancer was reviewed, with particular regard to the interindividual variation that exists in the development of pancreatic adenocarcinoma. RESULTS: Tobacco-derived carcinogen-metabolizing enzyme gene variants have been the main area of study in stratifying the risk of sporadic pancreatic cancer. Inconsistent results have emerged from the few molecular epidemiological studies performed. CONCLUSION: There is great scope for further investigation of critical pathways and unidentified genetic influences may be revealed. This may eventually allow the identification of individuals at high risk who might be targeted for screening.


Subject(s)
Carcinoma, Pancreatic Ductal/genetics , Genetic Predisposition to Disease/genetics , Pancreatic Neoplasms/genetics , Carcinogens/analysis , DNA Repair , Environment , Humans , Life Style , Pedigree , Prospective Studies , Risk Factors , Smoking/adverse effects
8.
Curr Pharm Des ; 13(32): 3292-300, 2007.
Article in English | MEDLINE | ID: mdl-18045181

ABSTRACT

Present treatment options for hepatocellular cancer (HCC) are limited to those individuals with good liver function and early stage disease. Unfortunately this includes only a minority of patients, few of which are actually cured of their cancer. Over the last 15-20 years biotechnology has made a very significant impact on medical research, to the extent that we know very much more about the regulation of normal cell growth and death, as well as the mechanisms underlying its disruption in disease processes. This knowledge has and is being rapidly exploited by academic and pharmaceutical organisations, often in collaboration. The result is the development, testing and steady introduction of therapies that target specific abnormalities in cancer cells. Although the safety and effectiveness of the majority of these agents has yet to be established in cirrhotic patients with HCC, we are hopeful that we will shortly see an increase in effective treatment options available for clinical use this disease. This review focuses on aberrant cancer proteins and pathways relevant to HCC, as well as the novel therapies or strategies targeting them, that are currently in the development or testing stages.


Subject(s)
Carcinoma, Hepatocellular/therapy , Liver Neoplasms/therapy , Carcinoma, Hepatocellular/etiology , Carcinoma, Hepatocellular/pathology , Cyclin-Dependent Kinases/antagonists & inhibitors , Cyclin-Dependent Kinases/metabolism , Cyclins/metabolism , DNA Damage/drug effects , Drug Delivery Systems , Humans , Liver Cirrhosis/complications , Liver Neoplasms/etiology , Liver Neoplasms/pathology , MAP Kinase Signaling System/drug effects , Phosphatidylinositol 3-Kinases/physiology , Proteasome Endopeptidase Complex/metabolism , Proteomics , Proto-Oncogene Proteins/metabolism , Receptor Protein-Tyrosine Kinases/metabolism , Retinoblastoma Protein/metabolism , Signal Transduction , Tumor Suppressor Protein p53/physiology
9.
Urology ; 66(5): 1110, 2005 Nov.
Article in English | MEDLINE | ID: mdl-16286148

ABSTRACT

Renal collecting duct carcinoma is a rare form of renal cancer known to present in a variety of ways that are often similar to presentations of renal cell carcinoma or transitional cell carcinoma. Little information is available concerning the use of cytology and fluorescence in situ hybridization (FISH) in the diagnosis of collecting duct carcinoma. The available literature contains cases with atypical cytology, but no collecting duct carcinoma cases with abnormal FISH results have been reported. We report a case of renal collecting duct carcinoma presenting with atypical cytology and abnormal FISH results.


Subject(s)
Carcinoma, Renal Cell/pathology , In Situ Hybridization, Fluorescence , Kidney Neoplasms/pathology , Adult , Female , Humans
10.
Science ; 294(5551): 2563-6, 2001 Dec 21.
Article in English | MEDLINE | ID: mdl-11752579

ABSTRACT

Kruppel-like factor 6 (KLF6) is a zinc finger transcription factor of unknown function. Here, we show that the KLF6 gene is mutated in a subset of human prostate cancer. Loss-of-heterozygosity analysis revealed that one KLF6 allele is deleted in 77% (17 of 22) of primary prostate tumors. Sequence analysis of the retained KLF6 allele revealed mutations in 71% of these tumors. Functional studies confirm that whereas wild-type KLF6 up-regulates p21 (WAF1/CIP1) in a p53-independent manner and significantly reduces cell proliferation, tumor-derived KLF6 mutants do not. Our data suggest that KLF6 is a tumor suppressor gene involved in human prostate cancer.


Subject(s)
Genes, Tumor Suppressor , Mutation , Prostatic Neoplasms/genetics , Proto-Oncogene Proteins , Trans-Activators/genetics , Alleles , Amino Acid Substitution , Animals , Cell Division , Cell Line , Chromosome Mapping , Chromosomes, Human, Pair 10/genetics , Cyclin-Dependent Kinase Inhibitor p21 , Cyclins/genetics , Cyclins/metabolism , Genetic Heterogeneity , Humans , Kruppel-Like Factor 6 , Kruppel-Like Transcription Factors , Loss of Heterozygosity , Male , Mice , Microsatellite Repeats , Mutation, Missense , Proliferating Cell Nuclear Antigen/metabolism , Promoter Regions, Genetic , Trans-Activators/chemistry , Trans-Activators/physiology , Transcriptional Activation , Tumor Cells, Cultured , Up-Regulation , Zinc Fingers
11.
Vet Rec ; 149(15): 449-52, 2001 Oct 13.
Article in English | MEDLINE | ID: mdl-11688747

ABSTRACT

A high basal plasma or serum insulin concentration is commonly accepted as an indicator of Cushing's disease in horses. The results of the combined dexamethasone suppression test and thyrotropin-releasing hormone stimulation test were compared with the basal insulin concentrations and insulin response tests of eight hyperinsulinaemic and insulin-resistant ponies with clinical histories of chronic or recurrent laminitis that were suspected of having Cushing's disease. Seven of the eight ponies had normal responses to the combined test indicating that basal insulin concentrations are not a specific indicator of the disease.


Subject(s)
Cushing Syndrome/veterinary , Horse Diseases/blood , Insulin/blood , Animals , Cushing Syndrome/blood , Cushing Syndrome/diagnosis , Dexamethasone , Female , Glucocorticoids , Horse Diseases/diagnosis , Horses , Hydrocortisone/blood , Male , Thyrotropin-Releasing Hormone
12.
J Hepatol ; 32(3): 465-72, 2000 Mar.
Article in English | MEDLINE | ID: mdl-10735617

ABSTRACT

BACKGROUND/AIMS: The signal cascades involved in the activation of hepatic stellate cells (HSC) are largely unknown. Factors initiating activation include tumour necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, endothelin, and oxidative stress. In other cell types some of these have been reported to stimulate p38 mitogen-activated protein (MAP) kinase and c-Jun N-terminal kinase (JNK). We have therefore investigated the role of these kinases in HSC activation. METHODS: HSC were isolated from male Wistar rats. Quiescent experiments were performed on day 2 HSC and transformed experiments on day 15 passage 1 HSC. Kinase activities were determined by immunoprecipitation and phosphorylation of specific substrate proteins and alpha-smooth muscle actin (SMA) expression by immunoblotting. RESULTS: The constitutive activity of p38 MAP kinase was higher in transformed versus quiescent cells. In quiescent cells TNFalpha stimulated p38 MAP kinase and JNK activities 12- and 4-fold respectively and this was halved by 2-mercaptoethanol, an indirect antioxidant. Endothelin-1 activated both kinases in quiescent cells via the endothelin-B receptor, while TGFbeta had no effect. Both 2-mercaptoethanol and a p38 inhibitor (SB202190) inhibited alpha-SMA expression by day 5 cells. CONCLUSIONS: The activation of p38 MAP kinase and JNK by TNFalpha and endothelin, together with the inhibition of this activation by 2-mercaptoethanol, provides indirect evidence supporting their role in HSC transformation. Direct evidence for a role for p38 MAP kinase is provided by the observations that its constitutive activity is higher in transformed versus quiescent cells and that its inhibitor reduces HSC activation in culture as assessed by alpha-SMA expression.


Subject(s)
Calcium-Calmodulin-Dependent Protein Kinases/physiology , Liver/physiology , Mitogen-Activated Protein Kinases/physiology , Actins/metabolism , Animals , Calcium-Calmodulin-Dependent Protein Kinases/antagonists & inhibitors , Cell Line, Transformed , Cells, Cultured , Endothelin-1/pharmacology , Enzyme Inhibitors/pharmacology , Imidazoles/pharmacology , JNK Mitogen-Activated Protein Kinases , Liver/cytology , Liver/enzymology , Male , Mercaptoethanol/pharmacology , Muscle, Smooth/metabolism , Pyridines/pharmacology , Rats , Rats, Wistar , Tumor Necrosis Factor-alpha/pharmacology , p38 Mitogen-Activated Protein Kinases
13.
Hepatology ; 31(1): 95-100, 2000 Jan.
Article in English | MEDLINE | ID: mdl-10613733

ABSTRACT

Platelet-derived growth factor (PDGF) is the most potent mitogen for hepatic stellate cells (HSCs) in vitro. The aim of this study was to investigate the role of the lipid-derived second messenger phosphatidic acid (PA) in mediating this effect and, in particular, to determine its interaction with the extracellular signal-regulated kinase (ERK) cascade. HSCs were isolated from rat livers. PA production was determined by lipid extraction and thin-layer chromatography (TLC) after prelabeling cells with [(3)H]myristate. ERK activity was measured by an in vitro kinase assay after immunoprecipitation. Mitogenic concentrations of PDGF, but not those of the relatively less potent mitogen, transforming growth factor alpha (TGF-alpha), stimulated the sustained production of PA from HSCs. Exogenous PA stimulated HSC proliferation and a sustained increase in ERK activity, and proliferation was completely blocked by the inhibition of ERK activation with PD98059. The stimulation of ERK by PDGF was of a similar magnitude but more sustained than that caused by TGF-alpha. These results suggest that the potent mitogenic effect of PDGF in HSCs may be caused, in part, by the generation of PA and subsequently by a more sustained activation of ERK than occurs with less potent mitogens that do not induce the production of this lipid second messenger.


Subject(s)
Cell Division , Liver/cytology , Phosphatidic Acids/physiology , Platelet-Derived Growth Factor/pharmacology , Animals , Diglycerides/biosynthesis , Enzyme Activation , Male , Mitogen-Activated Protein Kinase 1/metabolism , Phosphatidic Acids/biosynthesis , Phosphatidic Acids/pharmacology , Rats , Rats, Wistar , Second Messenger Systems , Transforming Growth Factor alpha/pharmacology
14.
Liver Transpl Surg ; 4(5): 404-9, 1998 Sep.
Article in English | MEDLINE | ID: mdl-9724478

ABSTRACT

Osteoporosis is common in patients with chronic cholestatic liver disease, and atraumatic spinal fracture is a recognized complication after orthotopic liver transplantation. Bisphosphonates are potent inhibitors of osteoclast bone resorption and have been successfully used to treat postmenopausal osteoporosis. We examined whether preoperative bone mineral density can predict the risk of fracture after orthotopic liver transplantation and whether intravenous bisphosphonate can prevent fractures in high-risk patients. Beginning in February 1993, standard bone mineral density measurements of the lumbar spine were performed as part of routine pretransplantation assessment. On the basis of a preliminary analysis from January 1995, patients with a lumbar spine bone mineral density of <0.84 g/cm2, or <84% of the predicted value (age/sex), were treated with intravenous bisphosphonate (pamidronate disodium) every 3 months before and for 9 months after liver transplantation. Bone mineral density measurements were available in 90 of 136 consecutive first transplants performed in our unit from February 1993 to September 1996. Before the use of pamidronate, 7 patients sustained symptomatic vertebral fractures. Their mean spine bone mineral density was lower than in the 38 patients with no clinical evidence of fracture (81.8% +/- 12.3% v 94.2% +/- 10.2%; P = .006). Since the introduction of pamidronate, no symptomatic vertebral fractures have occurred. Of 29 surviving patients with bone mineral density <0.84 g/cm2 before transplantation, 38% who did not receive treatment with pamidronate suffered spontaneous fracture, whereas 0 of 13 who received treatment suffered such a complication. A low lumbar spine bone mineral density is associated with a high risk of symptomatic vertebral fracture after liver transplantation. These results suggest that this risk is considerably reduced by the administration of intravenous bisphosphonate before and after transplantation.


Subject(s)
Diphosphonates/administration & dosage , Liver Transplantation/adverse effects , Osteoporosis/prevention & control , Absorptiometry, Photon , Adult , Aged , Bone Density , Female , Follow-Up Studies , Fractures, Spontaneous/etiology , Fractures, Spontaneous/metabolism , Fractures, Spontaneous/prevention & control , Humans , Infusions, Intravenous , Liver Failure/surgery , Lumbar Vertebrae/injuries , Lumbar Vertebrae/metabolism , Male , Middle Aged , Osteoporosis/complications , Osteoporosis/metabolism , Pamidronate , Retrospective Studies , Spinal Fractures/etiology , Spinal Fractures/metabolism , Spinal Fractures/prevention & control , Treatment Outcome
15.
J Hepatol ; 25(5): 677-83, 1996 Nov.
Article in English | MEDLINE | ID: mdl-8938545

ABSTRACT

BACKGROUND/AIMS: There is now overwhelming evidence that hepatic stellate cells are the principal cells involved in hepatic fibrogenesis. In several different forms of liver injury it has been demonstrated that they proliferate and undergo phenotypic transformation (activation) into matrix-producing, myofibroblast-like cells in response to necroinflammation, mediated in part, by Kupffer cell-derived factors. In alcoholic liver disease, however, the observation that fibrosis can occur in the absence of alcoholic hepatitis has cast doubt on necroinflammation being an absolute pre-requisite for alcohol-related hepatic stellate cells proliferation/activation and subsequent fibrogenesis. METHODS: Evidence for hepatic stellate cells activation has been sought in liver biopsies from 38 well-documented alcoholic patients with no evidence of alcoholic hepatitis or cirrhosis and eight normal controls. Activated hepatic stellate cells were identified immunohistochemically using a specific monoclonal antibody to detect cytoplasmic alpha smooth muscle actin (alpha-SMA), which is not present in quiescent cells. Kupffer cells were detected with the monoclonal antibody KP1 and collagen was stained using Sirius red. Immunoreactive cells and the amount of fibrosis were quantified, using a Kontron Vidas Image Analyser. Steatosis was graded from 0 (none-few hepatocytes containing fat) to 3 (> 2/3 hepatocyte containing fat). RESULTS: Biopsies from alcoholic patients contained significantly greater numbers of activated hepatic stellate cells (alpha-SMA+ve) than control biopsies (average cell counts: 84 +/- 11/mm2 versus 23 +/- 5/mm2, p < 0.0001). There was no correlation between numbers of activated hepatic stellate cells and either numbers of Kupffer cells or amount of fibrosis. There was, however, a significant correlation between hepatic stellate cells activation and steatosis (grade 0, 15 +/- 7 cells/unit area (n = 4), grade 1, 56 +/- 16 (n = 13), grade 2, 85 +/- 20 (n = 9), grade 3, 137 +/- 19 (n = 12); p = 0.002, ANOVA). CONCLUSIONS: These results suggest that neither necroinflammation nor an increase in Kupffer cells is an absolute prerequisite for hepatic stellate cells proliferation/activation and subsequent fibrogenesis in alcoholic liver disease. The correlation between alcohol-induced hepatic stellate cells activation and severity of steatosis is likely to reflect that both are attributable in part to the metabolic consequences of ethanol metabolism, namely increased concentrations of acetaldehyde and lipid peroxidation.


Subject(s)
Fatty Liver, Alcoholic/pathology , Liver Cirrhosis, Alcoholic/pathology , Liver/pathology , Transformation, Genetic , Analysis of Variance , Biopsy , Cell Count , Disease Progression , Hepatitis/pathology , Humans , Kupffer Cells/pathology , Liver Diseases, Alcoholic/pathology
16.
Arch Biochem Biophys ; 321(1): 199-208, 1995 Aug 01.
Article in English | MEDLINE | ID: mdl-7639521

ABSTRACT

The cytosolic form of NADP+:isocitrate dehydrogenase, a primary source of the NADPH required for de novo fatty acid synthesis in lactating bovine mammary gland, was studied to determine possible mechanisms of regulation by fatty acyl-coenzyme A (CoA). The reduction of NADP+ by the enzyme is inhibited by palmitoyl-CoA. In steady-state experiments, when added enzyme is used to start the reaction, analyses of velocity versus palmitoyl-CoA concentration as a binding isotherm, following the assumptions of Wyman's theory of thermodynamic linkage, suggested that binding of palmitoyl-CoA produced two different inhibitory effects on the enzyme. This analysis suggested inhibition first through binding to sites with an average dissociation constant of 3.3 microM, then by binding to sites with an average dissociation constant of 294 microM. When the enzyme is preincubated with palmitoyl-CoA there is an induction of a significant lag-burst reaction rate (hysteretic kinetics). Preincubation of the enzyme with its substrate, metal-isocitrate complex, nearly abolished the lag time and decreased the degree of inhibition. Changes in lag time and percentage inhibition as a function of concentration of palmitoyl-CoA followed patterns, similar to those observed in steady-state reactions, where the enzyme is not preincubated. Examination of the effect of acyl chain length at 300 microM demonstrated that only long-chain CoA's with carbon numbers > 14 have pronounced effects on kinetics. CoA alone has little or no effect, while stearoyl-CoA completely inhibited the enzyme. Other C18 acyl groups produced varying effects depending on the degree of unsaturation and cis-trans isomerism. NADP+:Isocitrate dehydrogenases, from other sources including that from Escherichia coli, do not show such sensitivity to acyl chain character under these conditions. Concentration ranges observed for these transitions are compatible with physiological conditions. This suggests that complexes of acyl-CoA's and NADP+:isocitrate dehydrogenase, in tissue rich in the cytoplasmic form of the enzyme, could be related to cytoplasmic events in the synthesis and secretion of lipid and possibly protein, since palmitoyl-CoA is known to promote secretory processes through acylation reactions which lead to vesicle fusion.


Subject(s)
Acyl Coenzyme A/pharmacology , Isocitrate Dehydrogenase/metabolism , Lactation , Mammary Glands, Animal/enzymology , Animals , Cattle , Female , Kinetics , Mathematics , Palmitoyl Coenzyme A/pharmacology , Structure-Activity Relationship
17.
Biochem Biophys Res Commun ; 182(1): 367-71, 1992 Jan 15.
Article in English | MEDLINE | ID: mdl-1731794

ABSTRACT

During growth on succinate, Acinetobacter calcoaceticus contains two forms of the enzyme isocitrate dehydrogenase. Addition of acetate to a lag-phase culture grown on succinate causes a dramatic increase in activity of form II of isocitrate dehydrogenase and in isocitrate lyase. Form II of isocitrate dehydrogenase may be responsible for the partition of isocitrate between the TCA cycle and the glyoxylate by-pass. This report describes the phosphorylation of the enzyme isocitrate lyase from A. calcoaceticus. This phosphorylation may be a regulatory mechanism for the glyoxylate by-pass.


Subject(s)
Acinetobacter calcoaceticus/enzymology , Isocitrate Lyase/metabolism , Acinetobacter calcoaceticus/growth & development , Autoradiography , Blotting, Western , Isocitrate Dehydrogenase/metabolism , Isocitrate Lyase/isolation & purification , Isoenzymes/metabolism , Phosphates/metabolism , Phosphorus Radioisotopes , Phosphorylation
18.
J Bacteriol ; 173(21): 6844-8, 1991 Nov.
Article in English | MEDLINE | ID: mdl-1938889

ABSTRACT

Acinetobacter calcoaceticus is capable of growing on acetate or compounds that are metabolized to acetate. During adaptation to growth on acetate, A. calcoaceticus B4 exhibits an increase in NADP(+)-isocitrate dehydrogenase and isocitrate lyase activities. In contrast, during adaptation to growth on acetate, Escherichia coli exhibits a decrease in NADP(+)-isocitrate dehydrogenase activity that is caused by reversible phosphorylation of specific serine residues on this enzyme. Also, in E. coli, isocitrate lyase is believed to be active only in the phosphorylated form. This phosphorylation of isocitrate lyase may regulate entry of isocitrate into the glyoxylate bypass. To understand the relationships between these two isocitrate-metabolizing enzymes and the metabolism of acetate in A. calcoaceticus B4 better, we have purified isocitrate lyase to homogeneity. Physical and kinetic characterization of the enzyme as well as the inhibitor specificity and divalent cation requirement have been examined.


Subject(s)
Acinetobacter calcoaceticus/enzymology , Isocitrate Lyase/isolation & purification , Amino Acid Sequence , Blotting, Western , Electrophoresis, Polyacrylamide Gel , Isocitrate Lyase/antagonists & inhibitors , Isocitrate Lyase/metabolism , Isoelectric Point , Kinetics , Metals/metabolism , Molecular Sequence Data , Molecular Weight
19.
Biochimie ; 71(9-10): 1065-70, 1989.
Article in English | MEDLINE | ID: mdl-2512997

ABSTRACT

Isocitrate lyase from Escherichia coli becomes phosphorylated in vitro by an endogenous kinase when partially purified extracts are incubated with [gamma-32P]ATP. Treatment of isocitrate lyase with histidine modifying reagents, and alkaline hydrolysis of in vitro phosphorylated enzyme indicated the presence of a phosphohistidine residue. Phosphorylation of isocitrate lyase can also occur in vivo, which indicates a possible regulatory significance of this modification. In addition to phosphorylation, isocitrate lyase is capable of incorporating label from both [alpha-32P]ATP and [14C]ATP suggesting that more than one type of covalent modification occurs on this enzyme. This report reviews the studies which have demonstrated the phosphorylation and modification of isocitrate lyase from Escherichia coli.


Subject(s)
Escherichia coli/enzymology , Isocitrate Lyase/metabolism , Oxo-Acid-Lyases/metabolism , Histidine , Phosphorylation
20.
Biochimie ; 71(9-10): 1095-100, 1989.
Article in English | MEDLINE | ID: mdl-2513001

ABSTRACT

In vivo labeling of Escherichia coli JA200 pLC 11-8 resulted in 32P incorporation into enolase as demonstrated by immunoaffinity chromatography and electrophoresis followed by autoradiography. Complete acid hydrolysis, followed by thin layer chromatography was employed for determination of the phosphoamino acid residue. Comparison with phosphoamino acid standards resulted in the identification of a labeled residue corresponding to phosphoserine. In vitro labeling of cell extracts from glucose and acetate grown cells resulted in differential labeling of enolase. When specific radioactivities of in vivo labeled enolase were compared, 7 times more label was incorporated at late log phase in glucose grown cells than in late log acetate grown cells. At stationary phase, only 2.5 times more label was incorporated into glucose compared to acetate. When 32P-labeled enolase from glucose grown cells was subjected to treatment with potato acid phosphatase, dephosphorylation of the enzyme could be observed. Monitoring enzyme activity during the acid phosphatase treatment revealed a 70% decrease for the forward enzyme reaction, and a 3-fold increase, followed by a gradual decrease to almost zero, for the reverse enzyme reaction. Complete reversal of the changes in activity was possible by adding an aliquot of partially purified enolase kinase plus ATP.


Subject(s)
Escherichia coli/enzymology , Acid Phosphatase/pharmacokinetics , Acid Phosphatase/pharmacology , Autoradiography , Blotting, Western , Chromatography, Affinity , Phosphorus Isotopes , Phosphorylation
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