Altered drug metabolism in parasitic diseases

While the immune system represents the main line of host defence against parasite infections, mixed function oxidase (MFO) systems (Box 1) offer the main line of defence against drugs and other biologically active substances. But, as this review shows, many parasites can exert a profound effect on the host MFO system by altering the microsomal drug-metabolizing enzymes and electron transport carriers such as cytochrome P-450. This can markedly affect the host's ability to metabolize biologically active compounds, often with adverse physiological, pharmacological and toxicological consequences. In mammals, drug metabolism occurs predominantly in the liver, and to a lesser extent in the spleen, lungs, kidneys, intestine and cerebral tissues. Thus those parasites that occupy sites in these tissues - such as amoebae, Fasciola, schistosomes and malaria - tend to be those with greatest effects on the host's ability to metabolize drugs. The effects can modify the host response to substances unrelated to the infection, and to drugs which may be administered under a chemotherapeutic regime.     

Effect of anthelmintics and phenothiazines on adenosine 5'-triphosphatases of filarial parasite Setaria cervi

S. cervi showed particulate bound Ca2+ ATPase and Na+,K(+)-ATPase activities while Mg2+ ATPase was detected in traces. ATPase of S. cervi was also differentiated from the nonspecific p-nitrophenyl phosphatase activity. Female parasite and microfilariae exhibited higher Ca2+ ATPase and Na+,K(+)-ATPase activities than the male adults and the enzyme Na+,K(+)-ATPase was mainly concentrated in the gastrointestinal tract of the filarial parasite. Na+,K(+)-ATPase of the filariid was ouabain-sensitive while Ca2(+)-ATPase activity was regulated by concentration of Ca2+ ions and inhibited by EGTA. Phenothiazines, viz. trifluoperazine, promethazine and chlorpromazine caused significant inhibition of Ca2+ ATPase and Na+,K(+)-ATPase. Diethylcarbamazine was a potent inhibitor of these ATPases. Mebendazole, levamisole and centperazine also caused significant inhibition of the ATPases indicating this enzyme system as a common target for the action of anthelmintic drugs.     

Molecular characterization and expression analysis of two crucial MAPKs- jnk1 and erk1 as cellular signal transducers in Labeo rohita in response to PAMPs stimulation and pathogenic invasion

Mitogen-activated protein kinases (MAPKs) are crucial Ser/Thr protein kinases that play important roles in innate immunity by converting extracellular stimuli into a wide range of cellular responses, including the production of cytokines. In this study, two MAPK genes, jnk1 and erk1, were cloned and characterized in rohu (Labeo rohita), a commercially important freshwater fish species in the Indian subcontinent. In healthy rohu, both jnk1 and erk1 gene expressions were highest in the spleen as compared to gill, liver, blood and kidney tissues. In vitro stimulation of the L. rohita gill (LRG) cell line with γ-D-glutamyl-meso-diaminopimelic acid, muramyl dipeptide and polyinosinic: polycytidylic acid (poly I:C) resulted in significantly enhanced expressions of jnk1 and erk1 genes. In the in vivo experiments, jnk1 and erk1 gene expressions were also enhanced in lipopolysaccharides and poly I:C-treatment. Infection of rohu fingerlings with Aeromonas hydrophila and Bacillus subtilis revealed significantly enhanced expressions of the jnk1 and erk1 genes in all of the tested organs/tissues. Together these results imply the important role of jnk1 and erk1 genes in fish during pathogenic invasion and diseases.     

Sequencing of the Dutch Elm Disease Fungus Genome Using the Roche/454 GS-FLX Titanium System in a Comparison of Multiple Genomics Core Facilities

As part of the DNA Sequencing Research Group of the Association of Biomolecular Resource Facilities, we have tested the reproducibility of the Roche/454 GS-FLX Titanium System at five core facilities. Experience with the Roche/454 system ranged from <10 to >340 sequencing runs performed. All participating sites were supplied with an aliquot of a common DNA preparation and were requested to conduct sequencing at a common loading condition. The evaluation of sequencing yield and accuracy metrics was assessed at a single site. The study was conducted using a laboratory strain of the Dutch elm disease fungus Ophiostoma novo-ulmi strain H327, an ascomycete, vegetatively haploid fungus with an estimated genome size of 30–50 Mb. We show that the Titanium System is reproducible, with some variation detected in loading conditions, sequencing yield, and homopolymer length accuracy. We demonstrate that reads shorter than the theoretical minimum length are of lower overall quality and not simply truncated reads. The O. novo-ulmi H327 genome assembly is 31.8 Mb and is comprised of eight chromosome-length linear scaffolds, a circular mitochondrial conti of 66.4 kb, and a putative 4.2-kb linear plasmid. We estimate that the nuclear genome encodes 8613 protein coding genes, and the mitochondrion encodes 15 genes and 26 tRNAs.     

Will an Unsupervised Self-Testing Strategy for HIV Work in Health Care Workers of South Africa? A Cross Sectional Pilot Feasibility Study

Background

In South Africa, stigma, discrimination, social visibility and fear of loss of confidentiality impede health facility-based HIV testing. With 50% of adults having ever tested for HIV in their lifetime, private, alternative testing options are urgently needed. Non-invasive, oral self-tests offer a potential for a confidential, unsupervised HIV self-testing option, but global data are limited.

Methods

A pilot cross-sectional study was conducted from January to June 2012 in health care workers based at the University of Cape Town, South Africa. An innovative, unsupervised, self-testing strategy was evaluated for feasibility; defined as completion of self-testing process (i.e., self test conduct, interpretation and linkage). An oral point-of-care HIV test, an Internet and paper-based self-test HIV applications, and mobile phones were synergized to create an unsupervised strategy. Self-tests were additionally confirmed with rapid tests on site and laboratory tests. Of 270 health care workers (18 years and above, of unknown HIV status approached), 251 consented for participation.

Findings

Overall, about 91% participants rated a positive experience with the strategy. Of 251 participants, 126 evaluated the Internet and 125 the paper-based application successfully; completion rate of 99.2%. All sero-positives were linked to treatment (completion rate:100% (95% CI, 66.0–100). About half of sero-negatives were offered counselling on mobile phones; completion rate: 44.6% (95% CI, 38.0–51.0). A majority of participants (78.1%) were females, aged 18–24 years (61.4%). Nine participants were found sero-positive after confirmatory tests (prevalence 3.6% 95% CI, 1.8–6.9). Six of nine positive self-tests were accurately interpreted; sensitivity: 66.7% (95% CI, 30.9–91.0); specificity:100% (95% CI, 98.1–100).

Interpretation

Our unsupervised self-testing strategy was feasible to operationalize in health care workers in South Africa. Linkages were successfully operationalized with mobile phones in all sero-positives and about half of the sero-negatives sought post-test counselling. Controlled trials and implementation research studies are needed before a scale-up is considered.     

Are Treponema pallidum Specific Rapid and Point-of-Care Tests for Syphilis Accurate Enough for Screening in Resource Limited Settings? Evidence from a Meta-Analysis

Background

Rapid and point-of-care (POC) tests for syphilis are an invaluable screening tool, yet inadequate evaluation of their diagnostic accuracy against best reference standards limits their widespread global uptake. To fill this gap, a systematic review and meta-analysis was conducted to evaluate the sensitivity and specificity of rapid and POC tests in blood and serum samples against Treponema pallidum (TP) specific reference standards.

Methods

Five electronic databases (1980–2012) were searched, data was extracted from 33 articles, and Bayesian hierarchical models were fit.

Results

In serum samples, against a TP specific reference standard point estimates with 95% credible intervals (CrI) for the sensitivities of popular tests were: i) Determine, 90.04% (80.45, 95.21), ii) SD Bioline, 87.06% (75.67, 94.50), iii) VisiTect, 85.13% (72.83, 92.57), and iv) Syphicheck, 74.48% (56.85, 88.44), while specificities were: i) Syphicheck, 99.14% (96.37, 100), ii) Visitect, 96.45% (91.92, 99.29), iii) SD Bioline, 95.85% (89.89, 99.53), and iv) Determine, 94.15% (89.26, 97.66). In whole blood samples, sensitivities were: i) Determine, 86.32% (77.26, 91.70), ii) SD Bioline, 84.50% (78.81, 92.61), iii) Syphicheck, 74.47% (63.94, 82.13), and iv) VisiTect, 74.26% (53.62, 83.68), while specificities were: i) Syphicheck, 99.58% (98.91, 99.96), ii) VisiTect, 99.43% (98.22, 99.98), iii) SD Bioline, 97.95%(92.54, 99.33), and iv) Determine, 95.85% (92.42, 97.74).

Conclusions

Rapid and POC treponemal tests reported sensitivity and specificity estimates comparable to laboratory-based treponemal tests. In resource limited settings, where access to screening is limited and where risk of patients lost to follow up is high, the introduction of these tests has already been shown to improve access to screening and treatment to prevent stillbirths and neonatal mortality due to congenital syphilis. Based on the evidence, it is concluded that rapid and POC tests are useful in resource limited settings with poor access to laboratories or screening for syphilis.     

Informing future cartilage repair strategies: a comparative study of three different human cell types for cartilage tissue engineering

A major clinical need exists for cartilage repair and regeneration. Despite many different strategies having been pursued, the identification of an optimised cell type and of pre-treatment conditions remains a challenge. This study compares the cartilage-like tissue generated by human bone marrow stromal cells (HBMSCs) and human neonatal and adult chondrocytes cultured on three-dimensional (3D) scaffolds under various conditions in vitro and in vivo with the aim of informing future cartilage repair strategies based upon tissue-engineering approaches. After 3 weeks in vitro culture, all three cell types showed cartilage-like tissue formation on 3D poly (lactide-co-glycolide) acid scaffolds only when cultured in chondrogenic medium. After 6 weeks of chondro-induction, neonatal chondrocyte constructs revealed the most cartilage-like tissue formation with a prominent superficial zone-like layer, a middle zone-like structure and the thinnest fibrous capsule. HBMSC constructs had the thickest fibrous capsule formation. Under basal culture conditions, neonatal articular chondrocytes failed to form any tissue, whereas HBMSCs and adult chondrocytes showed thick fibrous capsule formation at 6 weeks. After in vivo implantation, all groups generated more compact tissues compared with in vitro constructs. Pre-culturing in chondrogenic media for 1 week before implantation reduced fibrous tissue formation in all cell constructs at week 3. After 6 weeks, only the adult chondrocyte group pre-cultured in chondrogenic media was able to maintain a more chondrogenic/less fibrocartilaginous phenotype. Thus, pre-culture under chondrogenic conditions is required to maintain a long-term chondrogenic phenotype, with adult chondrocytes being a more promising cell source than HBMSCs for articular cartilage tissue engineering.     

Alterations of the Characteristics of the Circadian Rest‐Activity Rhythm of Cancer In‐Patients

The aim of the present study was to evaluate the characteristics of the circadian rest‐activity rhythm of cancer patients. Thirty‐one in‐patients, consisting of 19 males and 12 females, were randomly selected from the Regional Cancer Center, Pandit Jawaharlal Nehru Medical College, Raipur, India. The rest‐activity rhythm was studied non‐invasively by wrist actigraphy, and compared with 35 age‐matched apparently healthy subjects (22 males and 13 females). All subjects wore an Actiwatch (AW64, Mini Mitter Co. Inc., USA) for at least 4–7 consecutive days. Fifteen‐second epoch length was selected for gathering actigraphy data. In addition, several sleep parameters, such as time in bed, assumed sleep, actual sleep time, actual wake time, sleep efficiency, sleep latency, sleep bouts, wake bouts, and fragmentation index, were also recorded. Data were analyzed using several statistical techniques, such as cosinor rhythmometry, spectral analysis, ANOVA, Duncan's multiple‐range test, and t‐test. Dichotomy index (I<O) and autocorrelation coefficient (r24) were also computed. The results validated a statistically significant circadian rhythm in rest‐activity with a prominent period of 24 h for most cancer patients and control subjects. Results of this study further revealed that cancer patients do experience a drastic alteration in the circadian rest‐activity rhythm parameters. Both the dichotomy index and r24 declined in the group of cancer patients. The occurrence of the peak (acrophase, Ø) of the rest‐activity rhythm was earlier (p<0.001) in cancer patients than age‐ and gender‐matched control subjects. Results of sleep parameters revealed that cancer patients spent longer time in bed, had longer assumed and actual sleep durations, and a greater number of sleep and wake bouts compared to control subjects. Further, nap frequency, total nap duration, average nap, and total nap duration per 1 h awake span were statistically significantly higher in cancer patients than control subjects. In conclusion, the results of the present study document the disruption of the circadian rhythm in rest‐activity of cancer in‐patients, with a dampening of amplitude, lowering of mean level of activity, and phase advancement. These alterations of the circadian rhythm characteristics could be attributed to disease, irrespective of variability due to gender, sites of cancer, and timings of therapies. These results might help in designing patient‐specific chronotherapeutic protocols.