Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 75
Filter
1.
Physiol Int ; 2021 Apr 08.
Article in English | MEDLINE | ID: mdl-33835941

ABSTRACT

Aging is a multifactorial process, which is considered as a decline over time. It is increasingly clear that there is a gender difference in aging and in the prevalence of age-related diseases as well. We aimed to examine the effects of the aging process in the colonic tissue of female Wistar rats aged 10 weeks (young) and 13 months (middle-aged) at an early stage, according to three main symptoms associated with aging: a decrease in the efficacy of the proteasome and muscle function and an increase in oxidative stress. The aging process was found to cause a significant decrease in ubiquitin C-terminal hydrolase ligase (UCHL-1) and a significant increase in 3-nitrotyrosine (3-NT), total glutathione (GSH), calcium (Ca2+), calcitonin gene-related peptide (CGRP) and superoxide dismutase (SOD) activity in middle-aged animals. In summary, it is suggested that the reduced activity of the proteasomal degradation system may be the result of the diminished expression of the UCHL-1 enzyme and the decreased levels of ubiquitin; furthermore, we found some key targets which may help to better understand the fundamental aging process.

3.
J Comp Pathol ; 171: 38-52, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31540624

ABSTRACT

Psittacines (e.g. parrots, macaws and cockatoos) are common companion animals that are also kept in zoos and private breeding collections. Despite this popularity, long-term, comprehensive studies of diagnostic data from captive psittacines are rare. This study was conducted to assess trends in disease prevalence and to describe causes of morbidity and mortality in psittacines submitted for post-mortem examination to the veterinary hospital and diagnostic laboratory at the University of Guelph, Ontario, Canada. Post-mortem reports of 1,850 psittacines from 1998 to 2017 were assessed and included 110 species from 45 genera. Birds were often diagnosed with infectious disease processes (n = 823; 44.5%), including viral (n = 428; 23.1%), bacterial (n = 284; 15.4%) and fungal (n = 161; 8.7%). Non-infectious disease processes (n = 1,076; 58.2%) were most commonly degenerative (n = 465; 25.1%), metabolic (n = 392; 21.2%) or haemodynamic (n = 270; 14.6%). Exploratory statistical analyses, used to guide further research, revealed significant correlations and associations among disease processes and genera, age categories and sex. This 19-year retrospective study is the first to be conducted in Canada for psittacine birds and provides a broad overview of disease prevalence that can be used as a baseline to inform other studies addressing common and uncommon diseases affecting these birds in the future.


Subject(s)
Bird Diseases/epidemiology , Infections/veterinary , Psittaciformes , Animals , Bird Diseases/diagnosis , Infections/diagnosis , Infections/epidemiology , Ontario/epidemiology , Prevalence , Retrospective Studies
4.
Homo ; 68(5): 398-409, 2017 Oct.
Article in English | MEDLINE | ID: mdl-29066093

ABSTRACT

Abdominal fat accumulation is a major risk factor for cardiometabolic morbidity and mortality. The purpose of the study is to assess the possibility of developing accurate estimation equations based on body measurements to determine total abdominal (TFA), subcutaneous (SFA) and visceral fat area (VFA). Hungarian volunteers (n=198) aged between 20 and 81 years were enrolled in the study, which was conducted between July and November 2014. All persons underwent anthropometric measurements and computer tomographic (CT) scanning. Sex-specific multiple linear regression analyses were conducted in a subgroup of 98 participants to generate estimation models, then Bland-Altman's analyses were applied in the cross-validation group to compare their predictive efficiency. The variables best predicting VFA were hip circumference, calf circumference and waist-to-hip ratio (WHR) for males (R2=0.713; SEE=5602.1mm2) and sagittal abdominal diameter (SAD), WHR, thigh circumference and triceps skinfold for females (R2=0.845; SEE=3835.6mm2). The SFA prediction equation included SAD, thigh circumference and abdominal skinfold for males (R2=0.848; SEE=4124.1mm2), body mass index and thigh circumference for females (R2=0.861; SEE=5049.7mm2). Prediction accuracy was the highest in the case of TFA: hip circumference and WHR for males (R2=0.910; SEE=5637.2mm2), SAD, thigh circumference and abdominal skinfold for females (R2=0.915; SEE=6197.5mm2) were used in the equations. The results suggested that deviations in the predictions were independent of the amount of adipose tissue. Estimation of abdominal fat depots based on anthropometric traits could provide a cheap, reliable method in epidemiologic research and public health screening to evaluate the risk of cardiometabolic events.


Subject(s)
Abdominal Fat/anatomy & histology , Adiposity , Anthropometry/methods , Abdominal Fat/diagnostic imaging , Adult , Aged , Aged, 80 and over , Biostatistics , Female , Humans , Male , Middle Aged , Obesity, Abdominal/diagnostic imaging , Obesity, Abdominal/pathology , Risk Factors , Tomography, X-Ray Computed , Waist-Hip Ratio , Young Adult
7.
Epidemiol Infect ; 142(7): 1411-21, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24029072

ABSTRACT

In Ontario, Canada, the number of Salmonella Enteritidis (SE) cases increased over the years 2005-2010. A population-based case-control study was undertaken from January to August 2011 for the purpose of identifying risk factors for acquiring illness due to SE within Ontario. A total of 199 cases and 241 controls were enrolled. After adjustment for confounders, consuming any poultry meat [adjusted odds ratio (aOR) 2·24, 95% confidence interval (CI) 1·31-3·83], processed chicken (aOR 3·32, 95% CI 1·26-8·76) and not washing hands following handling of raw eggs (OR 2·82, 95% CI 1·48-5·37) were significantly associated with SE infection. The population attributable fraction was 46% for any poultry meat consumption and 10% for processed chicken. Poultry meat continues to be identified as a risk factor for SE illness. Control of SE at source, as well as proper food handling practices, are required to reduce the number of SE cases.


Subject(s)
Community-Acquired Infections/epidemiology , Salmonella Infections/epidemiology , Salmonella enteritidis/isolation & purification , Adolescent , Adult , Animals , Case-Control Studies , Chickens , Child , Child, Preschool , Community-Acquired Infections/microbiology , Eggs/microbiology , Feeding Behavior , Female , Hand Disinfection , Humans , Infant , Male , Meat/microbiology , Middle Aged , Multivariate Analysis , Odds Ratio , Ontario/epidemiology , Risk Factors , Salmonella Infections/microbiology , Surveys and Questionnaires , Young Adult
9.
Vox Sang ; 104(1): 46-54, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22827736

ABSTRACT

BACKGROUND AND OBJECTIVES: G-CSF-mobilized peripheral blood stem cells have long replaced marrow as the major source for allogeneic transplants. Conclusive evidence questioning the long-term safety of G-CSF for donors has not been provided, but the cumulative number of followed donors remains insufficient to rule out rare adverse events. A long-term active follow-up study of G-CSF-mobilized healthy volunteer donors was therefore performed. PATIENTS AND METHODS: Two hundred and three successive donors were evaluated pre-apheresis, subjected to G-CSF-mobilization/apheresis, and actively followed for 5 years by the same physicians and laboratories. Follow-up laboratory work included standard biochemical/haematological tests and T-cell phenotyping. RESULTS: Donor epidemiology was typical for reported stem cell donor cohorts. Acute adverse effects of G-CSF and apheresis were mild and transient, consistent with the previous reports. Mean circulating CD34(+) cells after nine doses of G-CSF were 124 per µl. Other biochemical/haematological parameters were also altered, consistent with G-CSF treatment. Spleen enlargement was modest. At first follow-up, all clinical and laboratory parameters had normalized. Leucocyte/lymphocyte counts and CD4/CD8 ratios were the same as during premobilization work-up and remained unchanged throughout. A single severe but likely unrelated adverse event, a case of papillary thyroid carcinoma, was reported. CONCLUSION: The studies add an observation time of almost 500 donor years to the growing body of evidence of the long-term safety of G-CSF for allogeneic donor stem cell mobilization.


Subject(s)
Blood Component Removal/methods , Blood Safety , Granulocyte Colony-Stimulating Factor/metabolism , Hematopoietic Stem Cell Mobilization/methods , Adult , Antigens, CD34/biosynthesis , CD4-Positive T-Lymphocytes/cytology , CD8-Positive T-Lymphocytes/cytology , Female , Filgrastim , Follow-Up Studies , Granulocyte Colony-Stimulating Factor/pharmacology , Humans , Longitudinal Studies , Lymphocyte Count , Male , Phenotype , Prospective Studies , Recombinant Proteins/pharmacology , Stem Cells/cytology , T-Lymphocytes/cytology , Tissue Donors , Transplantation, Homologous/methods
10.
Thromb Haemost ; 103(2): 450-60, 2010 Feb.
Article in English | MEDLINE | ID: mdl-20024490

ABSTRACT

We investigated the protective effect of ischaemic preconditioning (IP) on the maintenance of coronary patency using on-line measurements of coronary pressures and blood flow in a closed-chest reperfused acute myocardial infarction (MI) model in pigs. Catheter-based 90-min occlusion followed by 60-min reperfusion of the left anterior descending coronary artery (LAD) was performed in anesthetised pigs (MI group). IP was applied (IP group) through two cycles of 5-min occlusion and 5-min reperfusion of the LAD before MI induction. Coronary patency was determined by measurements of coronary wedge pressure, collateral fractional flow reserve (FFRcoll), collateral pressure index (CPI) and absolute coronary blood flow (CBF). Inducible and constitutive nitric oxide synthase (iNOS/cNOS) activities and expressions were determined in the myocardium. Plasma levels of myeloperoxidase (MPO, index of activated leukocytes) and mean platelet volume (MPV, index of activated platelets) were measured. IP resulted in significantly lower levels of MPO (0.52 +/- 0.19 vs. 1.05 +/- 0.24 U/l, p<0.001) and MPV (9.1 +/- 0.6 vs. 9.6 +/- 1.0 fl, p=0.04), higher FFRcoll (0.17 +/- 0.05 vs. 0.04 +/- 0.05, p<0.001), CPI (0.13 +/- 0.05 vs. 0.02 +/- 0.05, p<0.001) and CBF (70.7 +/- 4.2 vs. 50.8 +/- 4.8 m/min, p<0.001) post-reperfusion as compared with the MI group. IP resulted in significantly higher cNOS activity and eNOS expression. Significant negative correlation was found between MPO and measures of coronary patency (FFRcoll, CPI and CBF) and cNOS activity. Moreover, cNOS activity correlated significantly with FFRcoll, CPI and CBF. In conclusion, IP attenuates the release of MPO and platelet activation, thereby contributing to the maintenance of vessel patency at microvascular level after reperfusion of the infarct-related artery.


Subject(s)
Blood Flow Velocity , Blood Pressure , Coronary Circulation/physiology , Ischemic Preconditioning, Myocardial/methods , Animals , Microcirculation , Myocardial Infarction/etiology , Myocardial Infarction/physiopathology , Peroxidase/blood , Platelet Activation , Swine , Vascular Patency
11.
Acta Neurochir (Wien) ; 150(3): 265-71, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18288441

ABSTRACT

The effects of the non-peptide vasopressin V(2) receptor antagonist 5-dimethylamino-1-[4-(2-methylbenzoylamino)benzoyl]-2,3,4,5-tetrahydro-1H-benzazepine hydrochloride (OPC-31260) on the cerebral oedema induced by general cerebral hypoxia were studied in rats. The general cerebral hypoxia was produced by bilateral common carotid ligation in Sprague-Dawley rats of the CFY strain. By 6 h after the ligation, half of the rats had died, but the survival rate was significantly higher following OPC-31260 administration. Electron microscopic examinations revealed typical ischaemic changes after the carotid ligation. The carotid ligation increased the brain contents of water and Na(+) and enhanced the plasma vasopressin level. The increased brain water and Na(+) accumulation was prevented by OPC-31260 administration, but the plasma vasopressin level was further enhanced by OPC-31260. These results demonstrate the important role of vasopressin in the development of the disturbances in brain water and electrolyte balance in response to general cerebral hypoxia. The carotid ligation-induced cerebral oedema was significantly reduced following oral OPC-31260 administration. The protective mechanism exerted by OPC-31260 stems from its influence on the renal vasopressin V(2) receptors. These observations might suggest an effective approach to the treatment of global hypoxia-induced cerebral oedema in humans.


Subject(s)
Antidiuretic Hormone Receptor Antagonists , Benzazepines/pharmacology , Brain Edema/drug therapy , Brain Edema/physiopathology , Brain Ischemia/complications , Brain Ischemia/physiopathology , Animals , Benzazepines/therapeutic use , Body Water/drug effects , Body Water/metabolism , Brain/drug effects , Brain/metabolism , Brain/pathology , Brain Edema/etiology , Brain Ischemia/pathology , Disease Models, Animal , Kidney/drug effects , Kidney/metabolism , Male , Microscopy, Electron, Transmission , Rats , Receptors, Vasopressin/metabolism , Sodium/metabolism , Survival Rate , Treatment Outcome , Vasopressins/metabolism , Water-Electrolyte Balance/drug effects , Water-Electrolyte Balance/physiology
12.
Br J Pharmacol ; 153(5): 983-91, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18157165

ABSTRACT

BACKGROUND AND PURPOSE: Leukotriene B(4) (LTB(4)), formed by the sequential actions of the 5-lipoxygenase (5-LO) and leukotriene A(4) hydrolase (LTA(4)H), is a pro-inflammatory mediator implicated in the pathogenesis of inflammatory bowel disease. However, inhibitors of 5-LO have not proved to be consistent in their therapeutic efficacy in colitis. Another approach to inhibiting LTB(4) synthesis is through the use of inhibitors of LTA(4)H, such as the novel, potent and selective compound, JNJ 26993135. EXPERIMENTAL APPROACH: The effect of oral administration of JNJ 26993135 has been evaluated in a rat model of colitis provoked by colonic instillation of trinitrobenzenesulphonic acid (TNBS). The extent and severity of the macroscopic inflammatory response, the colonic levels of myeloperoxidase (MPO) and LTB(4) and of the pro-inflammatory cytokines, tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) were measured. KEY RESULTS: Oral administration of JNJ 26993135 (5, 15 and 30 mg kg(-1), twice a day) dose-dependently reduced both the extent and intensity of the colonic inflammatory damage observed 3 days after TNBS challenge. JNJ 26993135 also dose-dependently reduced the elevated colonic levels of LTB(4), as well as the inflammatory biomarkers, MPO, IL-6 and TNF-alpha. This dosing regimen was supported by the pharmacokinetic profile of JNJ 26993135, along with the demonstration of the inhibition of ex vivo production of LTB(4) in whole blood following oral administration. CONCLUSIONS AND IMPLICATIONS: These results with JNJ 26993135 in the rat TNBS model support the role of LTB(4) in colitis and the potential value of targeting LTA(4)H for the treatment of inflammatory bowel diseases.


Subject(s)
Benzothiazoles/pharmacology , Colitis/drug therapy , Enzyme Inhibitors/pharmacology , Epoxide Hydrolases/antagonists & inhibitors , Inflammation/drug therapy , Piperidines/pharmacology , Administration, Oral , Animals , Benzothiazoles/administration & dosage , Benzothiazoles/pharmacokinetics , Colitis/chemically induced , Colitis/physiopathology , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Delivery Systems , Enzyme Inhibitors/administration & dosage , Enzyme Inhibitors/pharmacokinetics , Inflammation/etiology , Interleukin-6/metabolism , Male , Peroxidase/drug effects , Peroxidase/metabolism , Piperidines/administration & dosage , Piperidines/pharmacokinetics , Rats , Rats, Wistar , Severity of Illness Index , Trinitrobenzenesulfonic Acid , Tumor Necrosis Factor-alpha/drug effects , Tumor Necrosis Factor-alpha/metabolism
13.
Surg Endosc ; 21(6): 1020-2, 2007 Jun.
Article in English | MEDLINE | ID: mdl-17332958

ABSTRACT

BACKGROUND: Intraoperative cholangiography (IOC) during laparoscopic cholecystectomy (LC) is used to assess the anatomy of the biliary tree and to detect any stones contained within it. Intraoperative cholangiography may be performed either routinely or more selectively in cases where there is a high suspicion of choledocholithiasis or for those patients whose anatomy appears unclear at operation [8]. In cases where significant inflammation is present, the cystic duct may be short, thickened, or dilated and thus difficult to manipulate to obtain a satisfactory IOC. METHODS: We describe a safe, simple, reliable technique to control the "difficult" cystic duct during IOC with a vascular vessel loop instead of a surgical clip to obtain good control and avoiding extravasation of dye during IOC. The feasibility, safety, and results of this technique are described. RESULTS: During a 1-year period, this technique has been used in 10 patients, and it was successful in all attempted cases, with a good quality IOC obtained on the first attempt. The cystic duct was then occluded in all cases using a Vicryl "0" endoloop. One patient had a common bile duct stone and this patient received postoperative endoscopic retrograde pancreatography (ERCP). All patients were discharged home with no complications. In cases where a short, thickened, or dilated cystic duct was present, ductal control during IOC was easily obtained using a vascular vessel loop. CONCLUSIONS: This is a safe, reliable, less traumatic, readily available, and inexpensive method that provides a secure way of handling the "difficult" cystic duct.


Subject(s)
Cholangiography/methods , Cholecystectomy, Laparoscopic/methods , Cystic Duct/surgery , Digestive System Diseases/surgery , Adult , Aged , Feasibility Studies , Female , Humans , Intraoperative Care , Male , Middle Aged
14.
AIDS Care ; 18(8): 952-60, 2006 Nov.
Article in English | MEDLINE | ID: mdl-17012085

ABSTRACT

HIV-disclosure among childbearing women remains poorly understood, particularly in sub-Saharan Africa. This paper chronicles disclosure experiences of 31 women attending prevention of mother-to-child HIV transmission services in Johannesburg. Data collection entailed repeat in-depth interviews over a nine-month period. Virtually all women (93.5%) had told at least one person (usually a partner), most voluntarily and within a week of the test result. Secondary disclosure was most likely with female family members, through indirect means and involuntary. Confidentiality breach by primary targets likely contributed to the observed high rates of involuntary secondary disclosure and negative secondary disclosure experiences. For most mothers, voluntary disclosure was driven by the desire to ensure adequate infant care and avoid vertical HIV transmission. The impact of disclosure was not always clear-cut. While most primary disclosure experiences were ultimately constructive, secondary disclosure more likely led to rejection, stigmatization and the withholding of financial support. Our data illustrate the influence of social contextual factors on disclosure patterns and impact. For these mothers, socio-cultural norms, the current media and political environment surrounding HIV/AIDS, household composition and social networks and childbearing status shaped disclosure experiences; sometimes constraining disclosure circumstances and sometimes creating a safe space to disclose. Programmatic implications are also discussed.


Subject(s)
HIV Seropositivity/psychology , Infectious Disease Transmission, Vertical/statistics & numerical data , Mothers/psychology , Pregnancy Complications, Infectious/etiology , Truth Disclosure , Adaptation, Psychological , Adult , Female , HIV Seropositivity/transmission , Humans , Pilot Projects , Pregnancy , Self Disclosure , Socioeconomic Factors , South Africa
15.
Neuroscience ; 141(4): 1919-24, 2006 Sep 15.
Article in English | MEDLINE | ID: mdl-16814932

ABSTRACT

Effects of chronic estrogen treatment on the survival rate of newly integrated interneurons were studied in the olfactory bulb of adult (250-300 g) female rats. Ovariectomized rats received 17-beta estradiol dissolved in sesame oil (i.p., 100 microg/100 g body weight [b.w.]) during six consecutive days, and on day 6 they were also injected with the mitotic marker 5-bromo-2-deoxyuridine (BrdU, i.p., 50 mg/kg b.w.) in every 2 hours during 8 hours. After 21 days of survival animals were killed and the density of BrdU-immunoreactive cells was analyzed in the granule cell and glomerular layer both in the main and accessory olfactory bulb. A significant decrease was found in the density of BrdU-labeled cells in both layers examined in the accessory olfactory bulb of ovariectomized and estradiol-treated rats when compared with those of ovariectomized and vehicle-treated animals. In the main olfactory bulb, in contrast, no difference was observed in the density of BrdU-immunoreactive cells in either of the two layers. Our results suggest that cells destined to the glomerular and granule cell layers react in the same way to chronic estrogen treatment, and the effect of estradiol is region specific, at least, within the olfactory bulb. 17-Beta estradiol reduces the density of newly generated cells in the accessory olfactory bulb, an area involved in the perception of pheromones, thus having a role in regulating sexual behavior, while the rate of integration and survival of newly born cells in the first relay station of the main olfactory pathway, i.e. the main olfactory bulb, remains unchanged.


Subject(s)
Bromodeoxyuridine/metabolism , Estrogens/pharmacology , Neurons/drug effects , Olfactory Bulb/cytology , Analysis of Variance , Animals , Cell Count/methods , Female , Immunohistochemistry/methods , Neurons/metabolism , Olfactory Bulb/drug effects , Ovariectomy/methods , Rats , Rats, Wistar , Time Factors
16.
AIDS Care ; 17(4): 466-70, 2005 May.
Article in English | MEDLINE | ID: mdl-16036232

ABSTRACT

In 2002, more than 280,000 HIV-exposed babies were born in South Africa. According to international PMTCT guidelines, these children require follow-up to 12 months of age. Worldwide, the high loss to follow-up rates experienced by PMTCT programs precludes them from identifying and managing HIV-infected children. Socio-economic factors have been identified as potential contributors to poor follow-up. A small descriptive study to examine socio-economic circumstances of women attending the Coronation Women and Children's Hospital PMTCT program was undertaken. Cross-sectional data from 176 women, interviewed at their infants' 12-month visit, was collected using a semi-structured questionnaire. Socio-economic factors such as poverty, geographical relocation and a lack of paternal support may affect the capacity of families to comply with the PMTCT follow-up program. Fifty-seven percent of mothers were unemployed, 25% of fathers did not support their children and only 58% of children remained resident in Johannesburg at the 12-month visit. The lack of follow-up of HIV-infected children denies them access to adequate medical care. Understanding the socio-economic factors that affect the ability of communities to comply with PMTCT programs will assist resource-poor countries in devising strategies to achieve follow-up of HIV-exposed infants.


Subject(s)
Child Health Services/statistics & numerical data , HIV Infections/epidemiology , Health Services Accessibility/statistics & numerical data , Patient Compliance , HIV Infections/therapy , Humans , Infant , Parents , Residence Characteristics , Social Support , Socioeconomic Factors , South Africa/epidemiology
17.
Health Care Women Int ; 26(5): 387-97, 2005 May.
Article in English | MEDLINE | ID: mdl-16020005

ABSTRACT

Mother-to-child transmission (MTCT) is the most common source of HIV infection in children. One topic that has received virtually no attention in MTCT-related research and programming is the psychosocial consequences among parents and families of receiving a definitive diagnosis of infant HIV status. This study explored experiences of HIV-infected mothers in Johannesburg, South Africa, regarding infant testing and diagnosis. Data collection entailed a key informant workshop and repeat interviews with a convenience sample of 31 HIV-infected mothers. While early testing was desirable, diagnosis had both beneficial and detrimental psychosocial effects, especially in instances of serodiscordance. Programmatic implications are discussed.


Subject(s)
Attitude to Health , HIV Infections/diagnosis , Infectious Disease Transmission, Vertical/prevention & control , Mothers , Pregnancy Complications, Infectious/diagnosis , Pregnancy Complications, Infectious/virology , Adult , Cultural Characteristics , Family Relations , Female , HIV Infections/psychology , HIV Infections/transmission , Humans , Infant Care/methods , Infant Welfare , Infant, Newborn , Maternal Welfare , Mothers/education , Mothers/psychology , Pregnancy , Pregnancy Complications, Infectious/prevention & control , Pregnancy Complications, Infectious/psychology , Social Support , South Africa , Surveys and Questionnaires
18.
Gene Ther ; 12(13): 1023-32, 2005 Jul.
Article in English | MEDLINE | ID: mdl-15815703

ABSTRACT

An objective of designing molecular vehicles exhibiting virus-like transgene delivery capabilities but with low toxicity and immunogenicity continues to drive synthetic vector development. As no single step within the gene delivery pathway represents the critical limiting barrier for all vector types under all circumstances, improvements in synthetic vehicle design may be aided by quantitative analysis of the contributions of each step to the overall delivery process. To our knowledge, however, synthetic and viral gene delivery methods have not yet been explicitly compared in terms of these delivery pathway steps in a quantitative manner. As a first address of this challenge, we compare here quantitative parameters characterizing intracellular gene delivery steps for an E1/E3-deleted adenoviral vector and three polyethylenimine (PEI)-based vector formulations, as well as the liposomal transfection reagent Lipofectamine and naked DNA; the cargo is a plasmid encoding the beta-galactosidase gene under a CMV promoter, and the cell host is the C3A human hepatocellular carcinoma line. The parameters were determined by applying a previously validated mathematical model to transient time-course measurements of plasmid uptake and trafficking (from whole-cell and isolated nuclei lysates, by real-time quantitative PCR), and gene expression levels, enabling discovery of those for which the adenoviral vector manifested superiority. Parameter-sensitivity analysis permitted identification of processes most critically rate-limiting for each vector. We find that the adenoviral vector advantage in delivery appears to reside partially in its import to the nuclear compartment, but that its vast superiority in transgene expression arises predominantly in our situation from postdelivery events: on the basis of per-nuclear plasmid, expression efficiency from adenovirus is superior by orders of magnitude over the PEI vectors. We find that a chemical modification of a PEI-based vector, which substantially improves its performance, appears to do so by enhancing certain trafficking rate parameters, such as binding and uptake, endosomal escape, and binding to nuclear import machinery, but leaves endosomal escape as a barrier over which transgene delivery could be most sensitively increased further for this polymer.


Subject(s)
Adenoviridae/genetics , Genetic Therapy/methods , Genetic Vectors/administration & dosage , Liver/metabolism , Models, Genetic , Polyethyleneimine , Cell Line , Gene Expression , Genetic Vectors/metabolism , Green Fluorescent Proteins/genetics , Humans , Liposomes , Plasmids , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and Specificity , Transfection/methods , Transgenes
19.
Mol Ther ; 4(5): 438-46, 2001 Nov.
Article in English | MEDLINE | ID: mdl-11708880

ABSTRACT

As intracellular gene delivery pathways are highly complex combinations of multiple potentially rate-limiting cellular and molecular processes, approaches to the design of synthetic delivery vectors focusing on any single barrier individually will likely be suboptimal. We offer here an "integrative systems" approach to vector characterization and design, combining quantitative experiment and computational modeling studies of vector uptake and trafficking kinetics. This model is validated using data for delivery of a green fluorescent protein (GFP)-encoding plasmid by means of Lipofectamine, permitting specification of model parameter values. The model is then used to make a priori predictions on the effect of polymer length in polyplex vectors, with additional parameter values determined from previous independent experimental studies of plasmid release. Comparison with data on GFP expression via these polyplex vectors shows that the model successfully predicts an experimentally observed biphasic dependence of expression efficiency on polymer length and quantifies the contributions of competing effects yielding the optimal intermediate polymer length. Finally, we use the model to predict potential effects of incorporating nuclear localization sequences in these kinds of synthetic vectors, and find that the degree of benefit from these will depend on the values of other key system properties including the vector unpackaging rate constant. Thus, we demonstrate the usefulness of a bioengineering, integrative-systems modeling approach to improved vector design and analysis.


Subject(s)
Evaluation Studies as Topic , Genetic Therapy/methods , Genetic Vectors/administration & dosage , Genetic Vectors/chemical synthesis , Biological Transport , Cation Exchange Resins/pharmacology , Cell Line , Computer Simulation , Gene Transfer Techniques , Genetic Vectors/genetics , Green Fluorescent Proteins , Humans , Kinetics , Lipids/pharmacology , Luminescent Proteins/analysis , Luminescent Proteins/genetics , Male , Nuclear Localization Signals , Plasmids/administration & dosage , Plasmids/chemical synthesis , Plasmids/genetics , Reproducibility of Results , Tumor Cells, Cultured
20.
AIDS Care ; 13(3): 351-65, 2001 Jun.
Article in English | MEDLINE | ID: mdl-11397337

ABSTRACT

This paper describes coping mechanisms used by commercial sex workers (CSWs) and their partners in confronting the threat of HIV. Data are part of a study exploring sexuality and HIV-related issues among members of the Durban commercial sex industry. Participants were 100 female CSWs, 25 male trucker driver clients and ten male personal partners. Data were collected using semi-structured questionnaires, focus group discussions and in-depth interviews. Analysis revealed high HIV-awareness and high prevalence of risky sexual behaviour. While they were acutely aware of the sex industry's potential role in HIV spread, study participants chose to remain sexually involved and engage in high risk sexual practices with both professional and personal partners. Men and women adopted several strategies to cope with the possibility of HIV infection: (1) denial of risk, (2) fatalism, (3) economic rationalization, (4) partner categorization through selective condom use, (5) purposeful ignorance of HIV status, and (6) abnegation of responsibility for practising safe sex. Among the most significant findings is the difference in study participants' handling of HIV risk and employing coping mechanisms in personal versus professional sexual situations. The implications of these coping strategies for HIV education, message development and intervention in the commercial sex industry and in general are discussed.


Subject(s)
Adaptation, Psychological , HIV Infections/psychology , Sex Work/psychology , Adult , Female , Focus Groups , HIV Infections/prevention & control , HIV Infections/transmission , Health Knowledge, Attitudes, Practice , Humans , Male , Risk-Taking , Sex Factors , Sexual Partners/psychology , South Africa
SELECTION OF CITATIONS
SEARCH DETAIL
...