How reproductive isolation is related to divergent natural selection is a central question in speciation. Here, we focus on several ecologically specialized taxa or ‘call types’ of red crossbills (Loxia curvirostra complex), one of the few groups of birds providing much evidence for ecological speciation. Call types differ in bill sizes and feeding capabilities, and also differ in vocalizations, such that contact calls provide information on crossbill phenotype. We found that two call types of red crossbills were more likely to approach playbacks of their own call type than those of heterotypics, and that their propensity to approach heterotypics decreased with increasing divergence in bill size. Although call similarity also decreased with increasing divergence in bill size, comparisons of responses to familiar versus unfamiliar call types indicate that the decrease in the propensity to approach heterotypics with increasing divergence in bill size was a learned response, and not a by-product of calls diverging pleiotropically as bill size diverged. Because crossbills choose mates while in flocks, assortative flocking could lead indirectly to assortative mating as a by-product. These patterns of association therefore provide a mechanism by which increasing divergent selection can lead to increasing reproductive isolation.
Loxia curvirostra; Pacific Northwest; playbacks; public information; reproductive isolation
Musculoskeletal symptoms are common adverse effects of statins, yet little is known about the prevalence of musculoskeletal pain and statin use in the general population.
We conducted a cross sectional study of the National Health and Nutrition Examination Survey (NHANES) 1999–2004. We estimated the prevalence of self-reported musculoskeletal pain according to statin use and calculated prevalence ratio estimates of musculoskeletal pain obtained from adjusted multiple logistic regression modeling.
Among 5,170 participants without arthritis, the unadjusted prevalence of musculoskeletal pain was significantly higher for statin users reporting pain in any region (23% among statin users, 95%CI: 19–27% compared to 18% among those not using statins, 95%CI: 17–20%; p=0.02) and in the lower extremities (12% among statin users, 95%CI: 8–16% compared to 8% among those not using statins, 95%CI: 7–9%; p=0.02). Conversely, among 3,058 participants with arthritis, statin use was not associated with higher musculoskeletal pain in any region. After controlling for confounders, among those without arthritis, statin use was associated with a significantly higher prevalence of musculoskeletal pain in any region, the lower back, and the lower extremities (adjusted prevalence ratios: 1.33 [1.06, 1.67]; 1.47 [1.02, 2.13]; 1.59 [1.12, 2.22], respectively). Among participants with arthritis, no association was observed between musculoskeletal pain and statin use on adjusted analyses.
In this population-based study, statin use was associated with a higher prevalence of musculoskeletal pain, particularly in the lower extremities, among individuals without arthritis. Evidence that statin use was associated with musculoskeletal pain among those with arthritis was lacking.
Statins; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Musculoskeletal Diseases; Arthritis
This study retrospectively evaluated long-term outcomes of 18 cats diagnosed with small intestinal adenocarcinoma, based on surgical versus non-surgical treatment and the presence or absence of metastasis at the time of surgery. Ten cats had surgery and histopathologic confirmation of adenocarcinoma and 8 cats did not have surgery but had cytologic diagnosis of adenocarcinoma. Median survival of cats with adenocarcinoma that underwent surgical excision was 365 days and 22 days for those with suspected adenocarcinoma that did not undergo surgery (P = 0.019). Median survival of cats was 843 days for those without evidence of metastatic disease at the time of surgery and 358 days for those that had (P = 0.25). In conclusion, surgical excision is beneficial in the treatment of small intestinal adenocarcinoma in the cat, including those patients with metastasis, and may result in a significantly longer survival time compared with patients which do not have their mass surgically excised.
Nociceptive pathways with first-order neurons located in the trigeminal ganglion (TG) provide sensory innervation to the head, and are responsible for a number of common chronic pain conditions, including migraines, temporomandibular disorders and trigeminal neuralgias. Many of those conditions are associated with inflammation. Yet, the mechanisms of chronic inflammatory pain remain poorly understood. Our previous studies show that the neurotrophin brain-derived neurotrophic factor (BDNF) is expressed by adult rat TG neurons, and released from cultured newborn rat TG neurons by electrical stimulation and calcitonin gene-related peptide (CGRP), a well-established mediator of trigeminal inflammatory pain. These data suggest that BDNF plays a role in activity-dependent plasticity at first-order trigeminal synapses, including functional changes that take place in trigeminal nociceptive pathways during chronic inflammation. The present study was designed to determine the effects of peripheral inflammation, using tooth pulp inflammation as a model, on regulation of BDNF expression in TG neurons of juvenile rats and mice. Cavities were prepared in right-side maxillary first and second molars of 4-week-old animals, and left open to oral microflora. BDNF expression in right TG was compared with contralateral TG of the same animal, and with right TG of sham-operated controls, 7 and 28 days after cavity preparation. Our ELISA data indicate that exposing the tooth pulp for 28 days, with confirmed inflammation, leads to a significant upregulation of BDNF in the TG ipsilateral to the affected teeth. Double-immunohistochemistry with antibodies against BDNF combined with one of nociceptor markers, CGRP or TRPV1, revealed that BDNF is significantly upregulated in TRPV1-immunoreactive (IR) neurons in both rats and mice, and CGRP-IR neurons in mice, but not rats. Overall, the inflammation-induced upregulation of BDNF is stronger in mice compared to rats. Thus, mouse TG provides a suitable model to study molecular mechanisms of inflammation-dependent regulation of BDNF expression in vivo.
CGRP; ELISA; Mouse; Nociceptor; Rat; TRPV1
We conducted a multi-center phase II trial of gemcitabine (G), carboplatin (C), dexamethasone (D), and rituximab (R) in order to examine its safety and efficacy as an outpatient salvage regimen for lymphoma. Fifty-one patients received 2–4 21-day cycles of G (1000mg/m2, days 1 and 8), C (AUC=5, day 1), D (40mg daily days 1–4), and R (375mg/m2, day 8 for CD20 positive disease) and were evaluable for response. Characteristics included: median age 58y (19–79y), stage III/IV 88%, elevated LDH 33%, median prior therapies 2, prior stem cell transplant 12%, chemoresistant 62%, median prior remission duration 2.5 months. The overall and complete response rates were 67% (95% confidence interval [CI], 54–80%) and 31% (95% CI 19–44%), respectively, with activity seen in a broad variety of histologies. Responses occurred in 16 of 17 (94%, 95% CI 83–100%) transplant eligible patients and 15 of 28 (54%, 95% CI 34–71%) with chemoresistant disease. The median CD34 yield in patients attempting peripheral blood stem cell (PBSC) collection following this regimen was 10.9 × 106 CD34+ cells/kg (range, 5.0 – 24.1 × 106). Hematologic toxicity was common but febrile neutropenia (2.5%) and grade 4 non-hematologic adverse events (n=2) were rare with no treatment-related deaths. GCD(R) is a safe and effective outpatient regimen for relapsed lymphoma and successfully mobilizes PBSC.
The Culex pipiens complex in Asia includes a temperate subspecies, Culex pipiens pallens, of uncertain taxonomic status. The shape of the male genitalia suggests it is a hybrid between Cx. pipiens and Cx. quinquefasciatus. We studied populations of Cx. p. pallens in Japan, Korea, and China and compared them to local populations of Cx. quinquefasciatus and Cx. p. pipiens. We examined variation in a nuclear intron in the acetylcholinesterase-2 gene [ACE] and eight microsatellite loci. We found a distinct microsatellite signature for Cx. p. pallens indicating restricted gene flow between Eastern and Western populations of Cx. pipiens, supporting the existence of two subspecies. Furthermore, a multilocus genotype analysis revealed current hybridization between Cx. p. pallens and Cx. quinquefasciatus in southern Japan, Republic of Korea, and China but not in Hokkaido, in northern Japan. Surprisingly, however, we found that the sex-linked ACE locus in chromosome I has introgressed asymmetrically through the males such that all male Cx. p. pallens have a copy of the Cx. quinquefasciatus ACE locus. This result highlights some of the potential consequences of hybridization between local and introduced species to disease transmission worldwide.
HYBRIDIZATION; GENETIC INTROGRESSION; SPECIATION; INVASIVE SPECIES; DISEASE VECTORS; ASIA; SEX-LINKED
This study will test the uptake and effectiveness of a flexible package of smoking cessation support provided primarily by the practice nurse (PN) and tailored to meet the needs of a diversity of patients.
This study is a cluster randomised trial, with practices allocated to one of three groups 1) Quit with Practice Nurse 2) Quitline referral 3) GP usual care. PNs from practices randomised to the intervention group will receive a training course in smoking cessation followed by access to mentoring. GPs from practices randomised to the Quitline referral group will receive information about the study and the process of written referral and GPs in the usual care group will receive information about the study. Eligible patients are those aged 18 and over presenting to their GP who are daily or weekly smokers and who are able to give informed consent. Patients on low incomes in all three groups will be able to access free nicotine patches.
Primary outcomes are sustained abstinence and point prevalence abstinence at the three month and 12 month follow-up points; and incremental cost effectiveness ratios at 12 months. Process evaluation on the reach and acceptability of the intervention approached will be collected through Computer Assisted Telephone Interviews (CATI) with patients and semi-structured interviews with PNs and GPs.
The primary analysis will be by intention to treat. Cessation outcomes will be compared between the three arms at three months and 12 month follow-up using multiple logistic regression. The incremental cost effectiveness ratios will be estimated for the 12 month quit rate for the intervention groups compared to usual care and to each other. Analysis of qualitative data on process outcomes will be based on thematic analysis.
High quality evidence on effectiveness of practice nurse interventions is needed to inform health policy on development of practice nurse roles. If effective, flexible support from the PN in partnership with the GP and the Quitline could become the preferred model for providing smoking cessation advice in Australian general practice.
Calorie restriction (CR) delays the development of age-associated disease and increases lifespan in rodents, but the effects in humans remain uncertain.
Determine the effect of 6 months of CR with or without exercise on cardiovascular disease (CVD) risk factors and estimated 10-year CVD risk in healthy non-obese men and women.
Thirty-six individuals were randomized to one of three groups for 6 months: Control, 100% of energy requirements; CR, 25% calorie restriction; CR+EX, 12.5% CR + 12.5% increase in energy expenditure via aerobic exercise. CVD risk factors were assessed at baseline, 3 and 6 months.
After 6 months, CR and CR+EX lost approximately 10% of body weight. CR significantly reduced triacylglycerol (-31 ± 15 mg/dL) and factor VIIc (-10.7 ± 2.3%). Similarly CR+EX reduced triacylglycerol (-22 ± 8 mg/dL) and additionally reduced LDL-C (-16.0 ± 5.1 mg/dL) and DBP (-4.0 ± 2.1 mmHg). In contrast, both triacylglycerol (24 ± 14 mg/dL) and factor VIIc (7.9 ± 2.3%) were increased in the control group. HDL-cholesterol was increased in all groups while hsCRP was lower in the Controls vs. CR+EX. Estimated 10-year CVD risk significantly declined from baseline by 29% in CR (P< 0.001) and 38% in the CR+EX (P<0.001) while remaining unchanged in the Control group.
Based on combined favorable changes in lipid and blood pressure, caloric restriction with or without exercise that induces weight loss favorably reduces risk for CVD even in already healthy non-obese individuals.
caloric restriction; exercise; cardiovascular risk factors; nutritional intervention; weight loss; aging
Cardiovascular disease is the major cause of premature death of Indigenous Australians, and despite evidence that cardiac rehabilitation (CR) and secondary prevention can reduce recurrent disease and deaths, CR uptake is suboptimal. The National Health and Medical Research Council (NHMRC) guidelines Strengthening Cardiac Rehabilitation and Secondary Prevention for Aboriginal and Torres Strait Islander peoples, published in 2005, provide checklists for services to assist them to reduce the service gap for Indigenous people. This study describes health professionals' awareness, implementation, and perspectives of barriers to implementation of these guidelines based on semi-structured interviews conducted between November 2007 and June 2008 with health professionals involved in CR within mainstream health services in Western Australia (WA). Twenty-four health professionals from 17 services (10 rural, 7 metropolitan) listed in the WA Directory of CR services were interviewed.
The majority of respondents reported that they were unfamiliar with the NHMRC guidelines and as a consequence implementation of the recommendations was minimal and inconsistently applied. Respondents reported that they provided few in-patient CR-related services to Indigenous patients, services upon discharge were erratic, and they had few Indigenous-specific resources for patients. Issues relating to workforce, cultural competence, and service linkages emerged as having most impact on design and delivery of CR services for Indigenous people in WA.
This study has demonstrated limited awareness and poor implementation in WA of the recommendations of the NHMRC Strengthening Cardiac Rehabilitation and Secondary Prevention for Aboriginal and Torres Strait Islander Peoples: A Guide for Health Professionals. The disproportionate burden of CVD morbidity and mortality among Indigenous Australians mandates urgent attention to this problem and alternative approaches to CR delivery. Dedicated resources and alternative approaches to CR delivery for Indigenous Australians are needed.
This study investigates the roles of Fer-CIP4 homology (FCH)-Bin/amphiphysin/Rvs (F-BAR) and SH2 domains of Fes protein tyrosine kinase in regulating its activation and signaling downstream of the high-affinity immunoglobulin G (IgE) receptor (FcɛRI) in mast cells. Homology modeling of the Fes F-BAR domain revealed conservation of some basic residues implicated in phosphoinositide binding (R113/K114). The Fes F-BAR can bind phosphoinositides and induce tubulation of liposomes in vitro. Mutation of R113/K114 to uncharged residues (RK/QQ) caused a significant reduction in phosphoinositide binding in vitro and a more diffuse cytoplasmic localization in transfected COS-7 cells. RBL-2H3 mast cells expressing full-length Fes carrying the RK/QQ mutation show defects in FcɛRI-induced Fes tyrosine phosphorylation and degranulation compared to cells expressing wild-type Fes. This correlated with reduced localization to Lyn kinase-containing membrane fractions for the RK/QQ mutant compared to wild-type Fes in mast cells. The Fes SH2 domain also contributes to Fes signaling in mast cells, via interactions with the phosphorylated FcɛRI β chain and the actin regulatory protein HS1. We show that Fes phosphorylates C-terminal tyrosine residues in HS1 implicated in actin stabilization. Thus, coordinated actions of the F-BAR and SH2 domains of Fes allow for coupling to FcɛRI signaling and potential regulation the actin reorganization in mast cells.
Submarine hydrothermal vents are model systems for the Archaean Earth environment, and some sites maintain conditions that may have favored the formation and evolution of cellular life. Vents are typified by rapid fluctuations in temperature and redox potential that impose a strong selective pressure on resident microbial communities. Nautilia profundicola strain Am-H is a moderately thermophilic, deeply-branching Epsilonproteobacterium found free-living at hydrothermal vents and is a member of the microbial mass on the dorsal surface of vent polychaete, Alvinella pompejana. Analysis of the 1.7-Mbp genome of N. profundicola uncovered adaptations to the vent environment—some unique and some shared with other Epsilonproteobacterial genomes. The major findings included: (1) a diverse suite of hydrogenases coupled to a relatively simple electron transport chain, (2) numerous stress response systems, (3) a novel predicted nitrate assimilation pathway with hydroxylamine as a key intermediate, and (4) a gene (rgy) encoding the hallmark protein for hyperthermophilic growth, reverse gyrase. Additional experiments indicated that expression of rgy in strain Am-H was induced over 100-fold with a 20°C increase above the optimal growth temperature of this bacterium and that closely related rgy genes are present and expressed in bacterial communities residing in geographically distinct thermophilic environments. N. profundicola, therefore, is a model Epsilonproteobacterium that contains all the genes necessary for life in the extreme conditions widely believed to reflect those in the Archaean biosphere—anaerobic, sulfur, H2- and CO2-rich, with fluctuating redox potentials and temperatures. In addition, reverse gyrase appears to be an important and common adaptation for mesophiles and moderate thermophiles that inhabit ecological niches characterized by rapid and frequent temperature fluctuations and, as such, can no longer be considered a unique feature of hyperthermophiles.
Extreme environments, such as deep-sea hydrothermal vents, found 2,500 meters below the ocean surface, support large macrofaunal communities via microbially mediated carbon fixation processes using chemicals (chemoautotrophy) rather than light (photoautotrophy). The genome of one such model chemoautotrophic microbe, N. profundicola, was sequenced and described in this work. N. profundicola, distantly related to the pathogenic Helicobacter and Campylobacter species, contains a number of genes and pathways predicted to be important in DNA repair, environmental sensing, and metabolism, which are novel to either its subdivision or to all microbes. The genes and deduced metabolic pathways include several hydrogen uptake and release systems as well as a novel predicted nitrogen assimilation pathway. One gene involved in DNA repair, reverse gyrase, was thought to be a hallmark protein in hyperthermophiles, which are microbes that grow above 80°C. We found this gene to be highly expressed at 65°C, over 20°C above the optimal growth temperature of this organism. Therefore, the genome of this model deep-sea hydrothermal vent chemoautotroph may reflect what is required for life in an extreme environment, hypothesized to be similar to early earth conditions.
Campylobacter jejuni, the commonest cause of bacterial diarrhoea worldwide, can also induce colonic inflammation. To understand how a previously identified heat stable component contributes to pro-inflammatory responses we used microarray and real-time quantitative PCR to investigate the transcriptional response to a boiled cell extract of Campylobacter jejuni NCTC 11168.
RNA was extracted from the human colonocyte line HCA-7 (clone 29) after incubation for 6 hours with Campylobacter jejuni boiled cell extract and was used to probe the Affymetrix Human Genome U133A array. Genes differentially affected by Campylobacter jejuni boiled cell extract were identified using the Significance Score algorithm of the Bioconductor software suite and further analyzed using the Ingenuity Pathway Analysis program. The chemokines CCL20, CXCL3, CXCL2, Interleukin 8, CXCL1 and CXCL6 comprised 6 of the 10 most highly up-regulated genes, all with Significance Scores ≥ 10. Members of the Tumor Necrosis Factor α/Nuclear Factor-κB super-family were also significantly up-regulated and involved in the most significantly regulated signalling pathways (Death receptor, Interleukin 6, Interleukin 10, Toll like receptor, Peroxisome Proliferator Activated Receptor-γ and apoptosis). Ingenuity Pathway Analysis also identified the most affected functional gene networks such as cell movement, gene expression and cell death. In contrast, down-regulated genes were predominantly concerned with structural and metabolic functions.
A boiled cell extract of Campylobacter jejuni has components that can directly switch the phenotype of colonic epithelial cells from one of resting metabolism to a pro-inflammatory one, particularly characterized by increased expression of genes for leukocyte chemoattractant molecules.
Radiation dermatitis is a common side effect of radiation therapy (RT). In severe cases, RT must be interrupted until the skin heals, which can compromise treatment. The purpose of the study was to compare an anionic polar phospholipid (APP)-based cream and an aloe vera-based gel to determine their effectiveness in preventing and treating radiation dermatitis.
Patients and methods
Forty-five pediatric patients (median age, 11 years) with various diagnoses who received at least 23.4 Gy participated. APP cream and aloe vera gel were symmetrically applied within the irradiated field after each treatment. Three measures were collected before, during and after completion of treatment: subject's skin comfort, dermatologic assessment, and common toxicity criteria (CTC).
Significant differences in specific variables favoring APP cream use were noted in some patients including skin comfort variables, dry (p = 0.002), soft (p = 0.057), feels good (p = 0.002), rough (p = 0.065), smooth (p = 0.012) and dermatologic variables, dryness (p = 0.013), erythema (p = 0.002) and peely (p = 0.008). Grouped CTC scores were supportive of APP cream (p = 0.004). In comparing the first and last assessments, two dermatologic variables, dryness (p = 0.035) and peely (p = 0.016), favored APP cream.
APP cream is more effective than aloe vera-based gel for prevention and treatment of radiation dermatitis.
Mutations in the RP1gene account for 6% to 10% of autosomal dominant retinitis pigmentosa (adRP). Previous studies have shown that the RP1gene is expressed specifically in photoreceptor cells. So far, little is known about the RP1 protein or how mutations in RP1lead to photoreceptor cell death. The goal of this study was to identify the RP1 protein and investigate its location in photoreceptor cells.
A combination of RT-PCR and rapid amplification of cDNA ends (RACE) was used to isolate the full-length mouse Rp1cDNA. Antibodies against different regions of the predicted mouse Rp1 protein were generated. Western blot analyses were used to identify the RP1/Rp1 proteins. The subcel-lular location of RP1 in human and mouse retinas was determined by immunostaining retinal sections.
The full-length mouse Rp1cDNA is 6944 bp, encoding a predicted protein of 2095 amino acids. Rp1 was found to be a soluble protein of approximately 240 kDa, consistent with predictions based on the cDNA sequence. Immunofluores-cence analyses revealed that both the human RP1 and mouse Rp1 proteins are specifically localized in the connecting cilia of rod and cone photoreceptors.
The presence of RP1/Rp1 in connecting cilia suggests that it may participate in transport of proteins between the inner and outer segments of photoreceptors or in maintenance of cilial structure. This study forms the basis for further investigation of the function of RP1 in retina and the mechanism by which mutations in RP1lead to photoreceptor cell death.(Invest Ophthalmol Vis Sci. 2002;43:22–2032)
Sclerosing epithelioid fibrosarcoma (SEF) has distinctive morphology and occurs mainly in deep soft tissue of adult extremities. Approximately 59 cases of SEF have been reported, with only 12 previously described in head and neck locations. Lesions involving the oral and maxillofacial region (OMFR) and intraosseous examples are rare. We present five cases of OMFRSEF. The OMF Pathology Department Registry was searched for cases coded from 1990 to the present as “SEF,” “fibrosarcoma not otherwise specified” or “neoplasm of uncertain histiogenesis.” Inclusion required OMFR location, an abundantly sclerotic sarcoma with epithelioid features, and lack of other phenotype by immunohistochemistry. Five cases of SEF included 3 males and 2 females. The age of the patients were: 19, 22, 35, 47 and 47 years. Tumor location included the infra-temporal fossa, buccal mucosa (recurrence extending into bone), anterior mandible (intraosseous primary, focally extending into soft tissue), and left parotid and submandibular gland (with metaplastic bone) regions. Tumor sizes ranged from 1.0 to 5.7 cm, median 3.5 cm. Histologically, the tumors were well delineated and multinodular, separated by fibrous septae. The spindled to primarily epithelioid tumor cells formed moderately cellular sheets and cords of irregularly contoured medium to large, round to oval, occasionally overlapping nuclei, indistinct nucleoli, wispy eosinophilic (retracting) cytoplasm, and distinctive cytoplasmic borders, embedded in osteoid-like stroma. Hemangiopericytoid (HPC-like) vessels were observed. Despite numerous apoptotic cells, mitoses were generally low; necrosis was present in two cases. Three tumors were graded as 2/3 and two 1/3. Immunohistochemically, the tumor cells were positive for vimentin, 1 case focally for CD34, whereas all cases were negative for S100 protein, keratins, EMA, desmin, and SMA. Wide or radical excision was performed with no adjuvant therapy. Follow-up revealed that 4 cases recurred at a range of 12–120 months. One case had no recurrent/residual disease at 3 months. Metastatic disease was present in 2 cases, to chest wall and lumbar/thoracic spine at 12 and 21 months, respectively. One patient died of disease complications at 15 months. OMFRSEF occur in adults in various locations, but with a common propensity to involve bone; there is recurrent potential and morbidity with higher grade lesions. The differential diagnosis for these tumors in this site includes sclerosing carcinoma, Ewing/PNET, osteosarcoma, osteoblastoma, and benign and malignant myoepithelial salivary gland tumors. The collagen, focal spindle cell features, HPC-like vasculature, and weak focal CD34 reactivity in one case might have raised a possible relationship between OMFRSEF and low grade malignant solitary fibrous tumor, but the intraosseous propensity, epithelioid features and relative lack of CD34 make this a distinctive entity.
Sclerosing epithelioid fibrosarcoma; Sarcoma; Oral; Maxillofacial
Phosphate enema toxicity was diagnosed in a 7-month-old, castrated male, pygmy goat. On presentation, clinical findings included mild depression, tachycardia, tachypnea, rumen stasis, muscle tremors, hypocalcemia, hypokalemia, hypochloremia, hyperphosphatemia, azotemia, and metabolic acidosis. Fluid diuresis and parenteral antimicrobial therapy resulted in recovery after 3 d of treatment.
Herpes simplex virus (HSV) DNA polymerase (Pol) mutations can confer resistance to all currently available antiherpetic drugs. However, discrimination between mutations responsible for drug resistance and those that are part of viral polymorphism can be difficult with current methodologies. A new system is reported for rapid generation of recombinant HSV type 1 (HSV-1) DNA Pol mutants based on transfection of a set of overlapping viral cosmids and plasmids. With this approach, twenty HSV-1 recombinants with single or dual mutations within the DNA pol gene were successfully generated and subsequently evaluated for their susceptibilities to acyclovir (ACV), foscarnet (FOS), cidofovir (CDV), and adefovir (ADV). Mutations within DNA Pol conserved regions II (A719T and S724N), VI (L778M, D780N, and L782I), and I (F891C) were shown to induce cross-resistance to ACV, FOS, and ADV, with two of these mutations (S724N and L778M) also conferring significant reduction in CDV susceptibility. Mutant F891C was associated with the highest levels of resistance towards ACV and FOS and was strongly impaired in its replication capacity. One mutation (D907V) lying outside of the conserved regions was also associated with this ACV-, FOS-, and ADV-resistant phenotype. Some mutations (K522E and Y577H) within the δ-region C were lethal, whereas others (P561S and V573M) induced no resistance to any of the drugs tested. Recombinants harboring mutations within conserved regions V (N961K) and VII (Y941H) were resistant to ACV but susceptible to FOS. Finally, mutations within conserved region III were associated with various susceptibility profiles. This new system allows a rapid and accurate evaluation of the functional role of various DNA Pol mutations, which should translate into improved management of drug-resistant HSV infections.
The microbicidal activity of sodium lauryl sulfate (SLS) against human immunodeficiency virus type 1 (HIV-1) was studied in cultured cells. Pretreatment of HIV-1NL4-3 with SLS decreased, in a concentration-dependent manner, its infectivity when using 1G5 as target cells. In the absence of a viral pretreatment period or when 1G5 cells were pretreated with SLS, the surfactant-induced inactivation of viral infectivity was less pronounced, especially at concentrations between 375 and 550 μM. SLS had no effect on HIV-1 when the virus was adsorbed to 1G5 cells by a 2-h incubation period. SLS almost completely inhibited the fusion process by decreasing the attachment of HIV-1 to target cells. SLS also inhibited the infectivity of HIV-1-based luciferase reporter viruses pseudotyped with the amphotropic murine leukemia virus envelope (which enters cells in a CD4-, CCR5-, and CXCR4-independent manner), indicating that SLS may inactivate other envelope viruses. In contrast, no effect was seen with vesicular stomatitis virus envelope glycoprotein G (which enters cells through receptor-mediated endocytosis) pretreated with up to 700 μM SLS. SLS also decreased, in a dose-dependent manner, the HIV-1-dependent syncytium formation between 1G5 and J1.1 cells after a 24-h incubation. The reduction of luciferase activity was more pronounced when J1.1 cells (which express HIV-1 proteins on their surface) were pretreated with SLS rather than 1G5 cells. Taken together, our results suggest that SLS could represent a candidate of choice for use in vaginal microbicides to prevent the sexual transmission of HIV and possibly other pathogens causing sexually transmitted diseases.
Clinical resistance of herpes simplex virus (HSV) types 1 and 2 to acyclovir (ACV) is usually caused by the presence of point mutations within the coding region of the viral thymidine kinase (TK) gene. The distinction between viral TK mutations involved in ACV resistance or part of viral polymorphism can be difficult to evaluate with current methodologies based on transfection and homologous recombination. We have developed and validated a new heterologous system based on the expression of the viral TK gene by the protozoan parasite Leishmania, normally devoid of TK activity. The viral TK genes from 5 ACV-susceptible and 13 ACV-resistant clinical HSV isolates and from the reference strains MS2 (type 2) and KOS (type 1) were transfected as part of an episomal expression vector in Leishmania. The susceptibility of TK-recombinant parasites to ganciclovir (GCV), a closely related nucleoside analogue, was evaluated by a simple measurement of the absorbance of Leishmania cultures grown in the presence of the drug. Expression of the TK gene from ACV-susceptible clinical isolates resulted in Leishmania susceptibility to GCV, whereas expression of a TK gene with frameshift mutations or nucleotide substitutions from ACV-resistant isolates gave rise to parasites with high levels of GCV resistance. The expression of the HSV TK gene in Leishmania provides an easy, reliable, and sensitive assay for evaluating HSV susceptibility to nucleoside analogues and for assessing the role of specific viral TK mutations.
The efficacy of sodium lauryl sulfate (SLS), a sulfated anionic chaotropic surfactant, and dextran sulfate (DS), a polysulfated carbohydrate, against herpes simplex virus (HSV) and human immunodeficiency virus (HIV) infections was evaluated in cultured cells and in different murine models of HSV infection. Results showed that both SLS and DS were potent inhibitors of the infectivities of various HSV-1 and HSV-2 strains. Pretreatment of HIV-1 (strain NL4-3) with SLS also reduced its infectivity to 1G5 cells. DS prevented the binding of HSV to cell surface receptors and therefore its entry into cells. Pretreatment of HSV-1 (strain F) with 50 μM SLS resulted in a complete loss of virus infectivity to Vero cells. However, viruses were able to enter into cells and to produce in the nuclei capsid shells devoid of a DNA core. The amount of the glycoprotein D gene produced in these cells remained unchanged compared to controls, suggesting that SLS could interfere with the maturation of the virus. At a higher SLS concentration (100 μM), HSV was highly damaged by SLS pretreatment and only a few viral particles could enter into cells to produce abnormal capsids. Although DS was a more potent inhibitor of HSV infectivity in vitro, it was unable to provide any protection in murine models of HSV infection. However, SLS conferred a complete protection of animals infected cutaneously with pretreated viruses. In addition, skin pretreatment of mice with a polymer formulation containing SLS completely prevented the development of cutaneous lesions. More interestingly, intravaginal pretreatment of mice with SLS in a buffered solution also completely protected against lethal HSV-2 infection. Taken together, our results suggest that SLS could thus represent a candidate of choice as a microbicide to prevent the sexual transmission of HIV, HSV, and possibly other pathogens that cause sexually transmitted diseases.