Neutrality, cross-immunity and subtype dominance in avian influenza viruses

Avian influenza viruses (AIVs) are considered a threat for their potential to seed human influenza pandemics. Despite their acknowledged importance, there are significant unknowns regarding AIV transmission dynamics in their natural hosts, wild birds. Of particular interest is the difference in subtype dynamics between human and bird populations-in human populations, typically only two or three subtypes cocirculate, while avian populations are capable of simultaneously hosting a multitude of subtypes. One species in particular-ruddy turnstones (Arenaria interpres)--has been found to harbour a very wide range of AIV subtypes, which could make them a key player in the spread of new subtypes in wild bird populations. Very little is known about the mechanisms that drive subtype dynamics in this species, and here we address this gap in our knowledge. Taking advantage of two independent sources of data collected from ruddy turnstones in Delaware Bay, USA, we examine patterns of subtype diversity and dominance at this site. We compare these patterns to those produced by a stochastic, multi-strain transmission model to investigate possible mechanisms that are parsimonious with the observed subtype dynamics. We find, in agreement with earlier experimental work, that subtype differences are unnecessary to replicate the observed dynamics, and that neutrality alone is sufficient. We also evaluate the role of subtype cross-immunity and find that it is not necessary to generate patterns consistent with observations. This work offers new insights into the mechanisms behind subtype diversity and dominance in a species that has the potential to be a key player in AIV dynamics in wild bird populations.

Dissecting a wildlife disease hotspot: the impact of multiple host species, environmental transmission and seasonality in migration, breeding and mortality

Avian influenza viruses (AIVs) have been implicated in all human influenza pandemics in recent history. Despite this, surprisingly little is known about the mechanisms underlying the maintenance and spread of these viruses in their natural bird reservoirs. Surveillance has identified an AIV 'hotspot' in shorebirds at Delaware Bay, in which prevalence is estimated to exceed other monitored sites by an order of magnitude. To better understand the factors that create an AIV hotspot, we developed and parametrized a mechanistic transmission model to study the simultaneous epizootiological impacts of multi-species transmission, seasonal breeding, host migration and mixed transmission routes. We scrutinized our model to examine the potential for an AIV hotspot to serve as a 'gateway' for the spread of novel viruses into North America. Our findings identify the conditions under which a novel influenza virus, if introduced into the system, could successfully invade and proliferate.

The consequences of climate change at an avian influenza 'hotspot'

Avian influenza viruses (AIVs) pose significant danger to human health. A key step in managing this threat is understanding the maintenance of AIVs in wild birds, their natural reservoir. Ruddy turnstones (Arenaria interpres) are an atypical bird species in this regard, annually experiencing high AIV prevalence in only one location-Delaware Bay, USA, during their spring migration. While there, they congregate on beaches, attracted by the super-abundance of horseshoe crab eggs. A relationship between ruddy turnstone and horseshoe crab (Limulus polyphemus) population sizes has been established, with a declining horseshoe crab population linked to a corresponding drop in ruddy turnstone population sizes. The effect of this interaction on AIV prevalence in ruddy turnstones has also been addressed. Here, we employ a transmission model to investigate how the interaction between these two species is likely to be altered by climate change. We explore the consequences of this modified interaction on both ruddy turnstone population size and AIV prevalence and show that, if climate change leads to a large enough mismatch in species phenology, AIV prevalence in ruddy turnstones will increase even as their population size decreases.

Imiquimod cream 5% for recalcitrant cutaneous warts in immunosuppressed individuals

BACKGROUND

Viral warts may cause significant morbidity in individuals unable to mount an adequate T-helper 1 cell-mediated immune response to human papillomavirus. Imiquimod is a potent inducer of antiviral cytokine activity which has shown significant efficacy in the treatment of genital warts. Similar efficacy in cutaneous warts is not yet established.

OBJECTIVES

To assess the response of persistent cutaneous warts to 5% imiquimod cream in immunosuppressed individuals.

METHODS

Fifteen immunosuppressed patients with warts on the hands and/or feet present for more than 18 months, which had failed to respond to a minimum of 12 weeks of topical salicylic acid and four cycles of cryotherapy, were recruited. Imiquimod 5% cream was applied in an open label, right vs. left comparison study for 24 weeks (three times weekly for 8 weeks, daily for 8 weeks, then daily with occlusion for 8 weeks).

RESULTS

Twelve (80%) patients completed the study protocol. Benefit was seen in five patients [36% in the intent-to-treat analysis (14 patients)], including more than 30% clearance of warts in three patients and reduction in overall size of warts in two further cases. Local skin reactions occurred in four (29%) patients and were usually mild. A transient rise in creatinine (11-29% above baseline) was measured in three renal transplant recipients, but we did not consider that this was related to imiquimod exposure.

CONCLUSIONS

This is the first controlled study to assess therapeutic efficacy of topical 5% imiquimod cream in persistent warts associated with immunosuppression. It provides preliminary evidence that topical imiquimod may benefit a subgroup of immunosuppressed patients with recalcitrant cutaneous warts.

Lack of mutations within ST7 gene in tumour-derived cell lines and primary epithelial tumours

ST7 is a candidate tumour suppressor gene at human chromosome locus 7q31.1. We have performed mutational analysis of ST7 in a wide-range of cell lines and primary epithelial cancers and detected only one missense change in a breast cancer cell line. Other mutations previously found in cell lines and primary tumours were not evident in our analysis. These results imply that another tumour suppressor gene at this locus may be more important than ST7 in carcinogenesis.

Reinforcement by orally delivered methadone, cocaine, and methadone-cocaine combinations in rhesus monkeys: are the combinations better reinforcers?

RATIONALE

Polydrug abuse is a problem that has been infrequently examined. In the present study, drug self-administration procedures were used to investigate the reinforcing effects of drug combinations.

OBJECTIVES

To determine the absolute and relative response rates maintained by orally delivered methadone, cocaine, and their combinations under sequential and concurrent access. Choice between drug combinations containing different concentrations of cocaine was also determined.

METHODS

Oral intake of methadone, cocaine, and their combinations was studied with rhesus monkeys during daily 3-h sessions. Lip contact (the operant response) was reinforced by delivery of liquid contingent upon completion of a fixed-ratio schedule. In one series, the drugs and drug combinations were studied sequentially with the water vehicle concurrently available. In the next series, the drugs and drug combinations were concurrently available. In the third series, pairs of drug combinations containing different concentrations of cocaine were also concurrently available.

RESULTS

Methadone, cocaine and their combinations functioned as reinforcers. Under sequential access, response rates for the drug combinations and the component drugs were often similar. However, under concurrent access, response rates for the drug combinations were greater than response rates for the component drugs at the highest FR size for each condition. Also, drug combinations containing higher cocaine concentrations were preferred to combinations containing lower cocaine concentrations.

CONCLUSIONS

Combinations of methadone and cocaine have relatively greater reinforcing effects than the component drugs, and these greater reinforcing effects are better detected with concurrent measures than with sequential measures.

Sertraline in children and adolescents with social anxiety disorder: an open trial

OBJECTIVE

The aim of this open-label study was to assess the therapeutic benefits, response pattern, and safety of sertraline in children with social anxiety disorder.

METHOD

Fourteen outpatient subjects with a primary Axis I diagnosis of social anxiety disorder were treated in an 8-week open trial of sertraline. Diagnostic and primary outcome measures included the Anxiety Disorders Interview Schedule for Children, Clinical Global Impressions scale (CGI), Social Phobia and Anxiety Inventory for Children, and a standardized behavioral avoidance test.

RESULTS

As measured by the CGI (Improvement subscale), 36% (5/14) of subjects were classified as treatment responders and 29% (4/14) as partial responders by the end of the 8-week trial. A significant clinical response appeared by week 6. Self-report and behavioral measures showed significant clinical improvement into normal range across all domains measured. The mean dose of sertraline was 123.21+/-37.29 mg per day. Sertraline was generally well tolerated.

CONCLUSION

In open treatment, sertraline resulted in significant improvement in symptoms of childhood social anxiety disorder. Absolute response rates varied depending on rating scales used. Findings from this study are sufficiently strong to warrant a future multisite, randomized, double-blind, placebo-controlled trial of sertraline for treatment of childhood social anxiety disorder.

Species- and brain region-specific dopamine transporters: immunological and glycosylation characteristics

Dopamine transporters (DATs) from the caudate nucleus of four species (rat, mouse, dog, and human) and four regions of rat brain (striatum, nucleus accumbens, prefrontal cortex, and midbrain) were photoaffinity labeled and analyzed by immunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis for cross-reactivity to four epitope-specific rat antipeptide antibodies. Each of these antibodies varied in its efficiency at recognizing DAT. The DATs from the rat brain regions exhibited the same degree of recognition by each of the four sera, a result compatible with these proteins being the product of a single gene. The DATs from the different species were recognized by all four sera but with different efficiencies, possibly relating to amino acid sequence differences within the immunizing epitope. All of the photolabeled, immunoprecipitated DATs migrated with a molecular mass of approximately 80 kDa, and no lower molecular mass forms were found. The DATs from all species and brain regions tested were shown by enzymatic deglycosylation to contain N-linked carbohydrates and sialic acids in amounts comparable with rat striatal DATs. The finding that no photolabeled DAT forms < 80 kDa were isolated from membranes indicates that partially or incompletely glycosylated forms are not present, even in the midbrain cell bodies where immature forms might be expected to be found. These findings verify the utility of these anti-rat antibodies as biochemical tools for studying DATs from other species and extend our knowledge of biochemical characteristics of DATs from these species and brain regions.

Effects of non-right-handedness on risk for sudden death associated with coronary artery disease

The hypothesis that non-right-handedness is associated with sudden cardiac death was tested based on evidence that sympathetic imbalance may contribute to ventricular arrhythmogenesis and evidence that left-handers may have a shorter lifespan than right-handers. The study included 26 patients with coronary artery disease (CAD), a history of ventricular tachycardia-ventricular fibrillation (VT-VF), and implanted defibrillators, and 26 patients with CAD and no history of serious arrhythmias who were matched for age, sex, and New York Heart Association functional class. Patients with any history of neurologic disorders were excluded. Left-handers either wrote with the left hand or were converted from left- to right-handedness in childhood. Non-right-handers used the left hand for writing, drawing, or throwing. Handedness rates in patients with VT-VF and case-control subjects were compared with published norms in the general population to take expected rates into account. The rates of left-handedness (6 of 26 or 23.1%) and non-right-handedness (9 of 26 or 34.6%) in patients with VT-VF were significantly higher (p < 0.003 and p < 0.0001, 2-tailed, respectively) than those of similarly aged adults in the general population (left-handedness, 5%; non-right-handedness, 10.2%). The rates of left-handedness (2 of 26 or 7.7%) and non-right-handedness (4 of 26 or 15.4%) observed in the case-control group correspond closely to the expected values for that group (left-handedness, 1.3 of 26 or 5%; non-right-handedness, 2.65 of 26 or 10.2%) derived from the general population rates and were not significantly different from them.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of heat inactivation and freezing on fatty acid composition of plasma and red blood cells

The effect of heat inactivation and freezing on fatty acid composition of plasma and red blood cells was investigated. Analysis was completed at baseline; after freezing; after incubation; after incubation and subsequent freezing; after incubation, freezing and a second incubation; and after freezing and subsequent incubation. There were changes in fatty acid levels observed in all groups with the phospholipid fractions showing the greatest changes. Those bloods that had been incubated, frozen and incubated again, and those which had been frozen initially followed by incubation showed the greatest change when compared to baseline samples. Even though there were changes in fatty acid levels seen in all groups, the changes were small except in those two groups. Treatment of blood with either of those two treatment regimens changes the fatty acid values so that they do not accurately reflect the composition of fatty acids in the blood.

Loss of heterozygosity involving the APC and MCC genetic loci occurs in the majority of human esophageal cancers

The tumor suppressor gene APC was recently identified, and the cDNA was cloned from chromosome 5q21. Point mutations affecting APC are seen in the hereditary syndrome familial adenomatous polyposis, and point mutations in APC and a closely linked gene, MCC, as well as loss of heterozygosity involving chromosome 5q have been reported in sporadic colon cancer. To our knowledge, loss of heterozygosity involving APC or MCC or both has not yet been described in any other human cancer besides lung cancer. We used the polymerase chain reaction and DNA content flow cytometric nuclear sorting to examine 30 primary human esophageal cancers for loss of heterozygosity of APC or MCC or both. Loss of one allele was detected in 77% of 26 informative cases. These data suggest that loss of heterozygosity of regions on 5q including the APC and MCC genetic loci is involved in the development and/or progression of most human esophageal cancers. They imply that inactivation of APC, MCC, and/or a linked gene on chromosome 5q plays a role in the pathogenesis of some cancers of the upper gastrointestinal tract, as well as in colon cancer and familial adenomatous polyposis.

Loss of heterozygosity affecting the p53, Rb, and mcc/apc tumor suppressor gene loci in dysplastic and cancerous ulcerative colitis

Allelic deletions of tumor suppressor genes have been observed frequently in a variety of human tumors. These losses are believed to contribute to the development of human cancer. Three of the most frequently deleted chromosomal loci contain the tumor suppressor genes p53, retinoblastoma (Rb), and mcc/apc. In order to detect loss of heterozygosity (LOH) within these genes in dysplastic and cancerous ulcerative colitis, we used an application of the polymerase chain reaction. LOH affecting p53 was observed in 8 of 17 (47%) of heterozygous patients, while LOH of Rb and the mcc/apc locus was observed in 9 of 27 (33%) and 13 of 39 (33%) of heterozygotes, respectively. Among 35 patients heterozygous at 2 or more loci, LOH of p53, Rb, and/or mcc/apc was observed in 18 (51%). LOH was more common in left-sided neoplasms. These data suggest that allelic deletion of p53, Rb, mcc, and/or apc is involved in the pathogenesis and/or progression of at least a subset of colonic dysplasias and carcinomas occurring in the setting of ulcerative colitis.

Near-hanging injury: two case studies and an overview

Near-hanging injuries result in respiratory, cardiac, neurologic, metabolic, and psychiatric problems. A patient surviving an attempted hanging can arrive at the emergency department in a comatose state, as documented in case 1, or in a conscious but disoriented state, as in case 2. Severe neurologic deficits are often reversible in cases of near-hanging. Regardless of initial findings, aggressive treatment of near-hanging victims should be initiated.

Nucleotide sequence of the 26 S mRNA of the virulent Trinidad donkey strain of Venezuelan equine encephalitis virus and deduced sequence of the encoded structural proteins

A cDNA clone containing all of the 26 S mRNA coding region of the RNA genome of Venezuelan equine encephalitis (VEE) virus, virulent strain Trinidad donkey (TRD), has been constructed and sequenced. The nucleotide and deduced amino acid sequences of the 26 S RNA of VEE virus conform to the general organization of the alphavirus subgenomic mRNA. Excluding the poly(A) tail, the VEE 26 S RNA is 3913 nucleotides long with a protein coding region of 3762 nucleotides. Codon usage in the translated region is nonrandom and correlates well with that reported for Sindbis (SIN), Semliki Forest (SF), and Ross River (RR) alphaviruses. Highly conserved sequences of 19 to 22 nucleotides representing putative replicase recognition sites occur at the 26 S RNA junction region of the 42 S genomic RNA and at the 3' terminus immediately preceding the poly(A) tail. The conserved sequence at the 26 S/42 S junction region of VEE virus differs from that of other alphaviruses in that an ochre termination codon (UAA) is substituted for a GGU (Gly) codon present in the other viruses. The 5' and 3' noncoding regions (30 and 121 nucleotides, respectively) of the VEE 26 S RNA are shorter than has been reported for several other alphaviruses. The approximate transmembrane domains of the VEE E1 and E2 envelope glycoproteins have been identified. VEE E1 contains a single asparagine-linked glycosylation site, whereas E2 has three such sites, all of which are apparently glycosylated. The deduced amino acid sequence of the VEE polyprotein shows an overall homology of 44 to 46% with the precursor polyproteins of SIN, SF, and RR viruses. VEE virus capsid, E1, and E2 structural proteins show 43 to 46%, 50 to 53%, and 36 to 41% homology, respectively, with the cognate proteins of SIN, SF, and RR viruses.

Coincident plasmids and antimicrobial resistance in marine bacteria isolated from polluted and unpolluted Atlantic Ocean samples

Sewage effluent and outfall confluence samples were collected at the Barceloneta Regional Treatment Plant in Barceloneta, Puerto Rico; outfall confluence samples at Ocean City, Md., were also collected. Samples from uncontaminated open ocean areas served as clean-water controls. Bacteria were enriched in marine broth 2216 amended with 1 microgram of one of a set of chemicals selected for study per ml: nitrobenzene, dibutyl phthalate, m-cresol, o-cresol, 4-nitroaniline, bis(tributyltin) oxide, and quinone. MICs of the chemicals were determined individually for all isolates. Bacterial isolates were evaluated for resistance to nine different antibiotics and for the presence of plasmid DNA. Treated sewage was found to contain large numbers of bacteria simultaneously possessing antibiotic resistance, chemical resistance, and multiple bands of plasmid DNA. Bacteria resistant to penicillin, erythromycin, nalidixic acid, ampicillin, m-cresol, quinone, and bis(tributyltin) oxide were detected in nearly all samples, but only sewage outfall confluence samples yielded bacterial isolates that were resistant to streptomycin. Bacteria resistant to a combination of antibiotics, including kanamycin, chloramphenicol, gentamicin, and tetracycline, were isolated only from sewage effluent samples. It is concluded that bacterial isolates derived from toxic chemical wastes more frequently contain plasmid DNA and demonstrate antimicrobial resistance than do bacterial isolates from domestic sewage-impacted waters or from uncontaminated open ocean sites.