Systems biology could help us harness useful microbes.
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Allergy and Immunology↗
Biomedical subjects
Douglas Young
Publications and source records attributed to Douglas Young.
The development and impact of tuberculosis vaccines.
Vaccination is expected to make a major contribution to the goal of eliminating tuberculosis worldwide by 2050. But developing a new effective vaccine will require innovation in scientific research, a proactive approach to clinical trials of new vaccine candidates, and application of vaccines as part of an integrated approach to disease control.
Animals↗
Identification of previously unrecognized antiestrogenic chemicals using a novel virtual screening approach.
The physiological roles of estrogen in sexual differentiation and development, female and male reproductive processes, and bone health are complex and diverse. Numerous natural and synthetic chemical compounds, commonly known as endocrine disrupting chemicals (EDCs), have been shown to alter the physiological effects of estrogen in humans and wildlife. As such, these EDCs may cause unanticipated and even undesirable effects. Large-scale in vitro and in vivo screening of chemicals to assess their estrogenic activity would demand a prodigious investment of time, labor, and money and would require animal testing on an unprecedented scale. Approaches in silico are increasingly recognized as playing a vital role in screening and prioritizing chemicals to extend limited resources available for experimental testing. Here, we evaluated a multistep procedure that is suitable for in silico (virtual) screening of large chemical databases to identify compounds exhibiting estrogenic activity. This procedure incorporates Shape Signatures, a novel computational tool that rapidly compares molecules on the basis of similarity in shape, polarity, and other bio-relevant properties. Using 4-hydroxy tamoxifen (4-OH TAM) and diethylstilbestrol (DES) as input queries, we employed this scheme to search a sample database of approximately 200,000 commercially available organic chemicals for matches (hits). Of the eight compounds identified computationally as potentially (anti)estrogenic, biological evaluation confirmed two as heretofore unknown estrogen antagonists. Subsequent radioligand binding assays confirmed that two of these three compounds exhibit antiestrogenic activities comparable to 4-OH TAM. Molecular modeling studies of these ligands docked inside the binding pocket of estrogen receptor alpha (ERalpha) elucidated key ligand-receptor interactions that corroborate these experimental findings. The present study demonstrates the utility of our computational scheme for this and related applications in drug discovery, predictive toxicology, and virtual screening.
Binding, Competitive↗
Cattle husbandry in Ethiopia is a predominant factor affecting the pathology of bovine tuberculosis and gamma interferon responses to mycobacterial antigens.
Bovine tuberculosis is a major economic problem and a potential public health risk. Improved diagnostics like the gamma interferon (IFN-gamma) test with ESAT6 and/or CFP10 could contribute to the control program. We assessed IFN-gamma responses in zebu (Ethiopian Arsi breed) and Holstein cattle kept indoors or in a pasture to tuberculin purified protein derivative (PPD) and an ESAT6-CFP10 protein cocktail. Furthermore, the intensity and distribution of pathology of bovine tuberculosis were compared between the two breeds. Our data demonstrated significantly (all P < 0.02) higher IFN-gamma responses to avian PPD, bovine PPD, and the ESAT6-CFP10 protein cocktail in Holstein than in zebu cattle, while lesion severities in infected animals and tuberculin skin test responses did not differ significantly (P > 0.05) between the two breeds. Holstein cattle that were kept indoors produced significantly (all P < 0.01) higher IFN-gamma levels in response to avian PPD, bovine PPD, and the ESAT6-CFP10 protein cocktail than did Holstein cattle kept in a pasture. Moreover, lesion severity was significantly higher in Holstein cattle kept indoors (P = 0.001) than in those kept in the pasture. Lesions were localized predominantly in the digestive tract in cattle kept in a pasture, while they were localized in the respiratory tract in cattle kept indoors. In conclusion, in Holstein cattle, husbandry was a dominant factor influencing the severity of tuberculosis lesions and IFN-gamma responses to mycobacterial antigens compared to breed. A difference in the cellular immune response between zebu and Holstein cattle was observed, while tuberculosis lesion severities were identical in the two breeds, when both were kept in a pasture.
Animal Husbandry↗
A multicenter, open-label study to evaluate satisfaction and menopausal quality of life in women using transdermal estradiol/norethindrone acetate therapy for the management of menopausal signs and symptoms.
AIM: This multicenter, open-label, single-arm study evaluated subject satisfaction and improvements in menopausal quality of life among menopausal women using the CombiPatch transdermal system consisting of 17beta-estradiol 0.05 mg plus norethindrone acetate 0.14 mg in a matrix patch formulation. METHODS: The 193 postmenopausal women between the ages of 45 and 65 years who comprised the modified intent-to-treat population (at least one patch and one efficacy assessment) were required to have reported at least five daily moderate-to-severe hot flashes and episodes of nocturnal sweating upon study entry for at least 1 month and applied one patch twice a week for 12 weeks. At weeks 0, 6, and 12, the women completed the Menopause-Specific Quality of Life (MENQOL) Questionnaire and, as a secondary study outcome, reported the scale of their application site discomfort. During weeks 1-12, they also kept diary records of number and severity of hot flashes and four other menopausal symptoms. Skin tolerance and adherence of the transdermal system were evaluated at weeks 6 and 12 by qualified evaluators. At week 6 and the end of the study, both subjects and physicians rated their satisfaction with the system. RESULTS: Among women in the modified intent-to-treat population, transdermal 17beta-estradiol plus norethindrone acetate significantly reduced the mean daily number of moderate-to-severe hot flashes experienced by women from 4.1 at week 1 to 0.6 at week 12 (p < 0.0001). The mean ratings of headache severity, insomnia, and vaginal irritation/dryness also improved significantly by week 6 and were maintained at week 12. At week 12, 92.4% of the subjects and 97.3% of the physicians reported that they were 'satisfied' or 'very satisfied' with the transdermal hormone delivery system. CONCLUSIONS: The results of this study compare favorably with previous placebo-controlled studies of transdermal hormone therapy in managing menopausal signs and symptoms. Furthermore, quality of life was significantly improved by the transdermal hormone therapy system, and both subjects and physicians reported high levels of satisfaction.
Administration, Cutaneous↗
Criminal recidivism in three models of mandatory drug treatment.
Although research has generally been supportive of compulsory treatment programs for drug abusers, findings remain mixed, and few studies have assessed the impacts of different coercive program elements. This study compared criminal recidivism outcomes of 350 clients mandated to the same long-term residential treatment facilities from three different legal sources. On several measures of recidivism, including long-term re-arrest rates that controlled for time at risk, clients mandated from two highly structured programs were found to recidivate at less than half the rate of comparison group clients. This group effect was upheld in multivariate models that controlled for pre-treatment differences and other factors related to recidivism. Combined with results of a previous retention study involving these clients, the findings provide support for the use of structured protocols for informing clients in mandatory programs about legal contingencies of participation and enforcing contingencies through frequent contact between legal agents and treatment staff.
Adult↗
Organ specificity, colonization and clearance dynamics in vivo following oral challenges with the murine pathogen Citrobacter rodentium.
Citrobacter rodentium belongs to a family of human and animal enteric pathogens that includes the clinically significant enterohaemorrhagic Escherichia coli (EHEC) and enteropathogenic E. coli (EPEC). These pathogens use attaching and effacing (A/E) lesions to colonize the host gastrointestinal tract. In this study we have used bioluminescence imaging (BLI) to investigate the organ specificity, dynamics of colonization and clearance of mice by C. rodentium in situ and in real time. The bioluminescent C. rodentium derivative, strain ICC180, expresses the luxCDABE operon from the entemopathogenic nematode symbiont Photorhabdus luminescens and light levels accurately reflect bacterial numbers both in vitro and in vivo. We have demonstrated that primary colonization of the mouse by C. rodentium takes place within the caecum, specifically within the specialized patch of lymphoid tissue known as the caecal patch. Following colonization of the caecum C. rodentium established a colonic infection. Clearance of C. rodentium ICC180 parallels the colonization dynamics, i.e. the caecum was first to be cleared followed by the colon. A bioluminescent eae (encoding the outer membrane adhesin intimin) C. rodentium mutant failed to establish long-term colonization, although low levels of bacteria could be recovered for up to 3 days post challenge from the caecum.
Adhesins, Bacterial↗
The 19-kDa Mycobacterium tuberculosis protein induces macrophage apoptosis through Toll-like receptor-2.
Macrophages infected with Mycobacterium tuberculosis undergo increased rates of apoptosis. Important objectives are to define the microbial factors that cause apoptosis, the mechanisms involved and the impact on infection. The 19-kDa M. tuberculosis glycolipoprotein (p19) is both cell wall-associated and secreted and is a candidate virulence factor. We investigated the potential of recombinant, His-tagged p19 lacking the secretion/acylation signal to induce macrophage apoptosis. The TUNEL assay and annexin V binding to membrane phosphatidylserine were used to measure apoptosis. The results show that p19 does act to induce apoptosis in differentiated THP-1 cells and monocyte-derived macrophages and that this effect is both dose- and time-dependent. Furthermore, this effect of p19 is Toll-like receptor (TLR)-2-mediated because preincubation of either THP-1 cells or TLR-2-expressing CHO cells with anti-TLR-2 mAb inhibited apoptosis induced by p19. Apoptosis of macrophages in response to p19 was found to be caspase-8 dependent and caspase-9 independent consistent with a transmembrane pathway signaling cell death through TLR-2. The viability of M. tuberculosis in cells undergoing apoptosis induced by p19 was significantly reduced suggesting the possibility that this may favor containment of infection. Although native p19 is a mycobacterial glycolipoprotein, based upon the use of recombinant p19 where the acylation signal had been removed, we conclude that it is the polypeptide component of p19 that is responsible for signaling through TLR-2 and that the lipid moiety is not required.
Animals↗
Conquistadors and Mycobacterium bovis.
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History, 16th Century↗
Prospects for molecular epidemiology of leprosy.
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DNA, Bacterial↗
Chronic bacterial infections: living with unwanted guests.
Some bacterial pathogens can establish life-long chronic infections in their hosts. Persistence is normally established after an acute infection period involving activation of both the innate and acquired immune systems. Bacteria have evolved specific pathogenic mechanisms and harbor sets of genes that contribute to the establishment of a persistent lifestyle that leads to chronic infection. Persistent bacterial infection may involve occupation of a particular tissue type or organ or modification of the intracellular environment within eukaryotic cells. Bacteria appear to adapt their immediate environment to favor survival and may hijack essential immunoregulatory mechanisms designed to minimize immune pathology or the inappropriate activation of immune effectors.
Animals↗
Characterization of mycobacterial protein glycosyltransferase activity using synthetic peptide acceptors in a cell-free assay.
Synthetic peptides derived from a 45-kDa glycoprotein antigen of Mycobacterium tuberculosis were shown to function as glycosyltransferase acceptors for mannose residues in a mannosyltransferase cell-free assay. The mannosyltransferase activity was localized within both isolated membranes and a P60 cell wall fraction prepared from the rapidly growing mycobacterial strain, Mycobacterium smegmatis. Incorporation of radiolabel from GDP-[(14)C]mannose was inhibited by the addition of amphomycin, indicating that the glycosyl donor for the peptide acceptors was a member of the mycobacterial polyprenol-P-mannose (PPM) family of activated glycosyl donors. Furthermore, a direct demonstration of transfer from the in situ generated PP[(14)C]Ms was also demonstrated. It was also found that the enzyme activity was sensitive to changes in overall peptide length and amino acid composition. Because glycoproteins are present on the mycobacterial cell surface and are available for interaction with host cells during infection, protein glycosyltransferases may provide novel drug targets. The development of a cell-free mannosyltransferase assay will now facilitate the cloning and biochemical characterisation of the relevant enzymes from M. tuberculosis.
Amino Acid Sequence↗
Patient satisfaction with alosetron for the treatment of women with diarrhea-predominant irritable bowel syndrome.
OBJECTIVE: The efficacy and tolerability of alosetron in women with diarrhea-predominant irritable bowel syndrome (IBS) have been established in double-blind, placebo-controlled trials. However, the degree to which alosetron fulfills the needs of those suffering from IBS has not been thoroughly examined from the patient's perspective. This randomized, double-blind, placebo-controlled study conducted in women with diarrhea-predominant IBS evaluated patients' overall satisfaction with treatment as well as their satisfaction with respect to several specific medication attributes. METHODS: Patients randomized to receive either alosetron 1 mg b.id. (n = 532) or placebo (n = 269) were administered a questionnaire on which they rated on 7-point Likert scales their prestudy IBS treatment (at the screening visit) or study medication (on wk 12 or final study visit) with respect to overall satisfaction and 11 specific medication attributes. RESULTS: Whereas approximately 10% of patients were satisfied or very satisfied overall with prestudy IBS medication, 69% of patients were satisfied or very satisfied overall with alosetron and 46% with placebo (p < 0.001) at the end of 12 wk of therapy. The majority of alosetron-treated patients (61-87%) were satisfied or very satisfied with each of 11 specific medication attributes (p < 0.001 vs placebo for each attribute). Favorable satisfaction ratings for alosetron were assigned to the five medication attributes that patients considered to be most important, including relief of urgency (68% alosetron vs 41% placebo), speed of relief (71% vs 40%), time to return to normal activities (75% vs 49%), relief of abdominal pain (62% vs 44%), and prevention of return of urgency (68% vs 42%). CONCLUSIONS: Women with diarrhea-predominant IBS are satisfied with alosetron 1 mg b.i.d. treatment overall and also with respect to specific attributes of IBS medication they consider most important.
Adult↗
Practical protocols for the prevention of dental disease in community settings for people with special needs: the protocols.
People with special needs have more dental disease and more missing teeth than the general population. They also have reduced access to oral health diagnostic, preventive, interceptive and treatment services. If services are available, they can be complicated and costly. It is critical to prevent dental diseases in these individuals. This article presents a set of practical protocols for preventing dental disease in people with special needs. These protocols are designed to be used in community settings outside of a dental office.
Anti-Infective Agents, Local↗
The use of topical fluoride to prevent or reverse dental caries.
Topical fluoride has been the main stay of caries prevention for many decades. There are several mechanisms which make it beneficial including inhibiting demineralization, enhancing remineralization, and inhibiting bacterial growth. Topical fluoride is available in many different forms. The concentrations of various fluoride preparations range from 225 parts per million (ppm) fluoride in over-the-counter oral rinses to 22,600 ppm in the fluoride varnishes. The clinician must decide which type of topical preparation is best suited for their patient. Patients with high caries risk may benefit from prescription strength fluorides (along with the other chemical and dietary therapies described in this issue of Special Care in Dentistry). The application of fluoride varnish is an excellent topical form for those patients who have access to dental care and for whom it is difficult to comply with the use of other topical forms.
Cariostatic Agents↗