Human papillomavirus infection and cervical disease in human immunodeficiency virus-1-infected women

OBJECTIVE: To report on the natural history of high-risk human papillomavirus (HPV) infection and cervical disease in human immunodeficiency virus (HIV)-1-infected women living in Cape Town, South Africa. METHODS: This was a prospective study of 400 untreated, HIV-1-infected women who underwent high-risk HPV DNA testing, cytology, colposcopy, histology, and CD4 count testing every 6 months for 36 months. Human immunodeficiency virus viral loads and HPV type distribution were determined at entry and after 18 months. RESULTS: Sixty-eight percent of the women were high-risk HPV DNA positive at entry, 35% had a cytologic diagnosis of low-grade squamous intraepithelial lesion (LSIL), and 13% had high-grade squamous intraepithelial lesion (HSIL). There were no cancers. Abnormal cytology and high-risk HPV positivity were strongly correlated with low CD4 counts and high HIV viral loads. The most prevalent types of HPV were HPV-16, -52, -53, -35, and -18. Incident high-risk HPV infection occurred in 22%, and of those infected with high-risk HPV, 94% of infections persisted over an 18-month period, and 6% cleared their infections. Cytologic progression to SIL from normal/atypical squamous cells of undetermined significance cytology occurred in 17% of cases, but only 4% of cases of LSIL progressed to HSIL. CONCLUSION: There is a high level of high-risk HPV infection in HIV-1 infected women, but progression to HSIL over 36 months occurred in the minority of cases. We recommend an initial colposcopy for an abnormal test, and if no high-grade lesion is identified, triennial screening would be appropriate. Human papillomavirus type 16 was the commonest, and HPV-18 was the fifth commonest, suggesting that vaccination against these two types would have a significant effect. LEVEL OF EVIDENCE: II.     

Impact of body mass index on IVF and ICSI outcome: a retrospective study

A group of 140 women with a body mass index (BMI) < or = 24 kg/m(2) undergoing 291 cycles was compared with a group of 138 women with a BMI >24 kg/m(2) in 291 cycles, with respect to duration of ovarian stimulation and dose of gonadotrophin, number of oocytes collected, cleavage and implantation rate, clinical pregnancy, miscarriage and delivery rates. Patients with a BMI > 24 kg/m(2) demonstrated a significant decrease in the number of follicles after stimulation (P = 0.01), a comparative increase in the number ampoules of gonadotrophin used (P = 0.03) and a lower number of eggs collected (P = 0.05). The mean number of embryos on days 1, 2 and 3 was significantly lower in the group with BMI > 24 kg/m(2) (P < 0.001). No significant difference was found in clinical pregnancy and miscarriage rates between the two groups. In spite of the lower response in women with BMI > 24 kg/m(2), the delivery rate per retrieval was not different (24.6 versus 24.8%). These results indicate a lower stimulation response in women with elevated BMI, but no adverse effect on IVF outcome. In relation to wellbeing, however, it is recommended that patients with a high BMI reduce their weight before IVF treatment.     

LCPT once‐daily extended‐release tacrolimus tablets versus twice‐daily capsules: a pooled analysis of two phase 3 trials in important de novo and stable kidney transplant recipient subgroups

African‐American and elderly kidney transplant recipients (KTR) have increased risk for poor clinical outcomes post‐transplant. Management of immunosuppression may be challenging in these patients and contribute to worse outcomes. A novel once‐daily formulation of tacrolimus (LCPT) has demonstrated noninferiority, similar safety, improved bioavailability, a consistent concentration time profile, and less peak and peak‐trough fluctuations vs. tacrolimus twice‐daily (Tac BID). This pooled analysis of two phase 3 randomized, controlled trials, including 861 (LCPT N = 428; Tac BID N = 433; 38% of patients were stable KTR, and 62% were de novo KTR) patients, examined the efficacy of LCPT in KTR subgroups (blacks, females, and age ≥65). Overall, treatment failure [death, graft failure, centrally read biopsy‐proven acute rejection (BPAR), or lost to follow‐up] at 12 months was as follows: LCPT: 11.9%, BID Tac: 13.4% [?1.48% (?5.95%, 2.99%)]. BPAR rates were as follows: LCPT: 8.2%, Tac BID: 9.5% [?1.29% (?5.14%, 2.55%)]. Numerically, fewer treatment failure events with LCPT were found in the majority of subgroups, with significantly less treatment failure associated with LCPT among black KTR [?13.82% (?27.22%, ?0.31%)] and KTR ≥65 [?13.46% (?25.27%, ?0.78%)]. This pooled analysis suggests numerically lower efficacy failure rates associated with LCPT among high‐risk subgroups, in particular black KTR and KTR ≥65 years old.     

Novel Linker Variants of Antileishmanial/Antitubercular 7-Substituted 2-Nitroimidazooxazines Offer Enhanced Solubility

Antitubercular 7-substituted 2-nitroimidazo[2,1-b][1,3]oxazines were previously shown to exhibit potent antileishmanial and antitrypanosomal activities, culminating in a new clinical investigational drug for visceral leishmaniasis (DNDI-0690). To offset development risks, we continued to seek further leads with divergent candidate profiles, especially analogues possessing greater aqueous solubility. Starting from an efficacious monoaryl derivative, replacement of the side chain ether linkage by novel amine, amide, and urea functionality was first explored; the former substitution was well-tolerated in vitro and in vivo but elicited marginal alterations to solubility (except through a less stable benzylamine), whereas the latter groups resulted in significant solubility improvements (up to 53-fold) but an antileishmanial potency reduction of at least 10-fold. Ultimately, we discovered that O-carbamate 66 offered a more optimal balance of increased solubility, suitable metabolic stability, excellent oral bioavailability (100%), and strong in vivo efficacy in a visceral leishmaniasis mouse model (97% parasite load reduction at 25 mg/kg).     

INAUGURAL ARTICLE by a Recently Elected Academy Member:Crystal structure and stability of gyrase–fluoroquinolone cleaved complexes from Mycobacterium tuberculosis

Mycobacterium tuberculosis (Mtb) infects one-third of the world’s population and in 2013 accounted for 1.5 million deaths. Fluoroquinolone antibacterials, which target DNA gyrase, are critical agents used to halt the progression from multidrug-resistant tuberculosis to extensively resistant disease; however, fluoroquinolone resistance is emerging and new ways to bypass resistance are required. To better explain known differences in fluoroquinolone action, the crystal structures of the WT Mtb DNA gyrase cleavage core and a fluoroquinolone-sensitized mutant were determined in complex with DNA and five fluoroquinolones. The structures, ranging from 2.4- to 2.6-Å resolution, show that the intrinsically low susceptibility of Mtb to fluoroquinolones correlates with a reduction in contacts to the water shell of an associated magnesium ion, which bridges fluoroquinolone–gyrase interactions. Surprisingly, the structural data revealed few differences in fluoroquinolone–enzyme contacts from drugs that have very different activities against Mtb. By contrast, a stability assay using purified components showed a clear relationship between ternary complex reversibility and inhibitory activities reported with cultured cells. Collectively, our data indicate that the stability of fluoroquinolone/DNA interactions is a major determinant of fluoroquinolone activity and that moieties that have been appended to the C7 position of different quinolone scaffolds do not take advantage of specific contacts that might be made with the enzyme. These concepts point to new approaches for developing quinolone-class compounds that have increased potency against Mtb and the ability to overcome resistance.The causative agent of tuberculosis (TB), Mycobacterium tuberculosis (Mtb), is one of the most important pathogens of humans, second only to the HIV in the number of deaths caused annually (1). Mtb is estimated to latently infect one-third of the world’s population (2), thereby also creating a huge reservoir for future disease. Particularly problematic are cases of multidrug-resistant (MDR)-TB, which is defined as resistance to two primary anti-TB drugs, rifampicin and isoniazid. MDR-TB now represents 3.5% of new TB cases; of these, 9% are classified as extensively drug-resistant (XDR)-TB (1), which is defined as MDR-TB with additional resistance to any fluoroquinolone and one injectable second-line drug (3). TB isolates are also being recovered that are totally drug-resistant (3–5). Thus, controlling TB, in particular drug-resistant TB, is a major health problem.Fluoroquinolones are one of the most successful classes of drugs against bacterial pathogens, accounting for 24% of the $10 billion antibiotic market (6). Fluoroquinolones are also currently receiving considerable attention in the treatment of TB, with two new C8-methoxy derivatives, moxifloxacin and gatifloxacin, currently under evaluation as promising first-line therapeutics (7–10). These compounds have been used to restrict the development of XDR-TB from MDR-TB; however, emerging resistance threatens both first-line and second-line use (11). The widespread testing of fluoroquinolones against TB has revealed considerable variation in efficacy of different drug variants against Mtb. For example, ciprofloxacin is only marginally active, and its early use with Mtb was halted in favor of ofloxacin and levofloxacin (7). These two agents are now proving to be less effective than moxifloxacin and gatifloxacin (7, 10); however, the newest two compounds also exhibit some nonideality. For example, gatifloxacin can elicit side effects such as hypo/hyperglycemia (12), whereas moxifloxacin has potential cardiovascular risks (13). Although recent clinical trials that have included fluoroquinolones as part of an alternative drug regimen have faltered (14), there are prospects for other nonfluoroquinolone molecules to make an impact on the treatment of MDR- and XDR-TB (15, 16). Moreover, a promising recent trial that uses moxifloxacin as part of a three-drug regimen together with pretomanid and pyrazinamide reports superior bactericidal activity against TB and MDR-TB versus current regimens (17). These new data make it clear that new quinolone-class agents, which are also capable of circumventing known resistance mutations, might be useful therapeutic agents in the treatment of TB.Progress is presently being made toward developing new fluoroquinolone derivatives. For example, a methoxy group at fluoroquinolone position C8 (Fig. 1A) increases activity against mycobacteria, particularly resistant mutants (18–20). Indeed, moxifloxacin, along with a more active C8-methyl derivative, retains high inhibitory activity against purified Mtb gyrase even when the enzyme contains commonly acquired fluoroquinolone-resistance substitutions [as described in the accompanying paper by Aldred et al. (21)]. In another example, quinazolinediones (diones) have been shown to have an ability to bypass existing resistance within mycobacteria and other bacterial species (20, 22–24). Thus, there still exist opportunities to design more effective quinolone-class molecules for treatment of TB.Open in a separate windowFig. 1.DNA cleavage by Mtb gyrase induced by fluoroquinolones. (A) Fluoroquinolones tested in this study. The constant quinolone core of each drug is highlighted in orange, numbered as shown around C8-Me-moxifloxacin. (B) DNA cleavage assays with full-length Mtb gyrase, using WT (upper gels) and a GyrA A90S (lower gels) sensitizing mutant. Each fluoroquinolone is titrated against a constant amount of protein (125 nM) and supercoiled (SC) plasmid DNA substrate (12.5 nM). The “no protein” control shows the supercoiled substrate DNA, along with a nicked (N) and linear (L) control lanes. Each gel is representative of triplicate data. (C) Graphical analysis of data in B. The relative amount of DNA cleavage is plotted as an increase in linear product (obtained by densitometry) compared with the zero drug control as a function of drug concentration. (Left) WT. (Right) A90S. Data points and error bars represent the mean and SD of triplicate data, respectively.DNA gyrase is a heterotetrameric (GyrA₂GyrB₂) enzyme that transiently catalyzes dsDNA breaks as it negatively supercoils DNA. Fluoroquinolones prevent the resealing of the ds breaks that normally follows DNA strand passage (25), generating persistent, covalent enzyme–DNA adducts called cleaved complexes. Cleaved-complex formation, which is reversible, blocks bacterial growth; at elevated fluoroquinolone concentrations, release of DNA breaks from the complexes leads to chromosome fragmentation and cell death (26). Although numerous crystallographic studies have defined the primary binding site of fluoroquinolones against gyrase (and against topoisomerase IV, a gyrase paralog) (27–30), there has been debate as to whether fluoroquinolones use a magnesium ion to bridge their interaction with the enzyme (28, 29). Resolving this question is important, because the intrinsic resistance of certain species of gyrase to quinolones (e.g., Mtb) has been proposed to result from natural sequence variation that leads to the loss of a magnesium-ion “bridge” formed between the drug and enzyme (31–33). At the same time, there currently exists no clear chemical explanation as to why certain fluoroquinolone derivatives act with different efficacies against Mtb gyrase.To better understand such questions, we carried out a structural and biochemical analysis of Mtb gyrase in the presence of a panel of four different, clinically used fluoroquinolones (ciprofloxacin, levofloxacin, gatifloxacin, and moxifloxacin) and one new fluoroquinolone derivative (C8-Me-moxifloxacin). X-ray crystallography revealed that Mtb gyrase indeed makes an intrinsically low number of interactions with a magnesium ion that accompanies fluoroquinolone binding, and that the introduction of a drug-sensitizing mutation (GyrA A90S) restores interactions seen in nonresistant gyrase homologs. In vitro, we find that C8-Me-moxifloxacin and moxifloxacin are most effective at promoting cleaved complex formation and inhibiting DNA supercoiling by Mtb gyrase, followed by gatifloxacin, and then ciprofloxacin and levofloxacin; however, crystal structures of the DNA-binding-and-cleavage core of Mtb gyrase with both DNA and drug surprisingly failed to reveal any substantial differences in the contacts formed between the protein and different drugs. Further biochemical investigations using an assay that monitors the stability of preformed cleaved complexes largely corroborated the rank order of inhibition seen in DNA cleavage experiments and moreover resulted in drug efficacy trends that closely accord with clinical effectiveness. Collectively, our data explain why Mtb gyrase is naturally quinolone-resistant and show that the relative activities of existing panels of anti-TB quinolone therapeutics are heavily influenced by base-stacking interactions and have yet to take advantage of direct gyrase contacts to maximize therapeutic potential.     

Cost effectiveness of decentralised care model for managing MDR-TB in India

Background

In India, multidrug-resistant tuberculosis (MDR-TB) patients are usually treated in hospitals. Decentralised care model, however, has been suggested as a possible alternative by the World Health Organization (WHO). In the “End TB Strategy”, the WHO highlights, as one of the key targets for 2035, that ‘no TB-affected families should face catastrophic hardship due to the tuberculosis’. Removal of financial barriers to health-care access and mitigation of catastrophic expenditures are therefore considered vital to achieve the universal health coverage (UHC) goal. Since forgoing healthcare due to the financial constraints is a known fact in India, decentralised care as an intervention choice (as against hospital-based care) might enhance equity provided it is an affordable choice. Thus, an economic evaluation was conducted, from the perspective of the national health system in India, to assess the cost-effectiveness of decentralised care compared to centralised care for MDR-TB.

Parental resilience: A neglected construct in resilience research

The substantial focus of resilience research on childhood well‐being has resulted in limited knowledge regarding other aspects of resilience in families, such as that of parents. Informed by literature in childhood and family resilience, in this review, we progress conceptual understanding by focusing on parental resilience. The definition of parental resilience, as the capacity of parents to deliver a competent and quality level of parenting to children despite the presence of risk factors, is offered here as a worthwhile framework through which to explore variables thought to contribute to resilience among parents. A conceptual model is proposed whereby parental psychological well‐being and self‐efficacy, family functioning, and social connectedness are specifically addressed, with each posited as playing an important role in parents’ ability to deliver high‐quality parenting. In addition to these factors, how parents accommodate adversity and find meaning in their everyday lives within their families is hypothesised to be an important process in understanding parental resilience.