The role of ecotype-environment interactions in intraspecific trophic niche partitioning subsequent to stocking

Worldwide, stocking of fish represents a valuable tool for conservation and maintenance of species exploited by recreational fishing. Releases of hatchery-reared fish are more and more recognized to have numerous demographic, ecological, and genetic impacts on wild populations. However, consequences on intraspecific trophic relationships have rarely been investigated. In this study, we assessed the impacts of supplementation stocking and resulting introgressive hybridization on the trophic niches occupied by stocked, local, and hybrid lake trout (Salvelinus namaycush) within populations of piscivorous and planktivorous ecotypes stocked from a wild piscivorous source population. We compared trophic niches using stable isotope analysis (δ¹³ C and δ¹⁵ N) and trophic position among the three genetic origins. Putative genetic effects were tested with phenotype-genotype association of "life history" ecological traits (body size, growth rate, condition index, and trophic niche) and genotypes (RADseq SNP markers) using redundant discriminant analysis (RDA). Results showed that sympatry resulting from the stocking of contrasting ecotypes is a risk factor for niche partitioning. Planktivorous populations are more susceptible to niche partitioning, by competitive exclusion of the local fish from a littoral niche to an alternative pelagic/profundal niche. Observed niche partitioning is probably a manifestation of competitive interactions between ecotypes. Our results emphasize that ecotypic variation should be considered for more efficient management and conservation practices and in order to mitigate negative impact of supplementation stocking.

Genetic architecture and maternal contributions of early-life survival in lake trout Salvelinus namaycush

The influences of additive, non-additive and maternal effects on early survival (uneyed embryo survival, eyed embryo survival, alevin survival and overall survival to first feeding) were quantified in lake trout Salvelinus namaycush using a 7 × 7 full-factorial breeding design. Maternal effects followed by non-additive genetic effects explained around one third of the phenotypic variance of the survival traits. Although the amount of additive genetic effects were low (<1%), suggesting a limited potential of the traits to respond to new selection pressures, how maternal and non-additive genetic effects may respond to selection under certain circumstances are discussed.

Gut dendritic cell activation links an altered colonic microbiome to mucosal and systemic T-cell activation in untreated HIV-1 infection

HIV-1-associated disruption of intestinal homeostasis is a major factor contributing to chronic immune activation and inflammation. Dendritic cells (DCs) are crucial in maintaining intestinal homeostasis, but the impact of HIV-1 infection on intestinal DC number and function has not been extensively studied. We compared the frequency and activation/maturation status of colonic myeloid DC (mDC) subsets (CD1c(+) and CD1c(neg)) and plasmacytoid DCs in untreated HIV-1-infected subjects with uninfected controls. Colonic mDCs in HIV-1-infected subjects had increased CD40 but decreased CD83 expression, and CD40 expression on CD1c(+) mDCs positively correlated with mucosal HIV-1 viral load, with mucosal and systemic cytokine production, and with frequencies of activated colon and blood T cells. Percentage of CD83(+)CD1c(+) mDCs negatively correlated with frequencies of interferon-γ-producing colon CD4(+) and CD8(+) T cells. CD40 expression on CD1c(+) mDCs positively associated with abundance of high prevalence mucosal Prevotella copri and Prevotella stercorea but negatively associated with a number of low prevalence mucosal species, including Rumminococcus bromii. CD1c(+) mDC cytokine production was greater in response to in vitro stimulation with Prevotella species relative to R. bromii. These findings suggest that, during HIV infection, colonic mDCs become activated upon exposure to mucosal pathobiont bacteria leading to mucosal and systemic immune activation.

Predictability of multispecies competitive interactions in three populations of Atlantic salmon Salmo salar

Juvenile Atlantic salmon Salmo salar from three allopatric populations (LaHave, Sebago and Saint-Jean) were placed into artificial streams with combinations of four non-native salmonids: brown trout Salmo trutta, rainbow trout Oncorhynchus mykiss, Chinook salmon Oncorhynchus tshawytscha and coho salmon Oncorhynchus kisutch. Non-additive effects, as evidenced by lower performance than predicted from weighted summed two-species competition trials, were detected for S. salar fork length (LF ) and mass, but not for survival, condition factor or riffle use. These data support emerging theory on niche overlap and species richness as factors that can lead to non-additive competition effects.

An altered intestinal mucosal microbiome in HIV-1 infection is associated with mucosal and systemic immune activation and endotoxemia

Human immunodeficiency virus-1 (HIV-1) infection disrupts the intestinal immune system, leading to microbial translocation and systemic immune activation. We investigated the impact of HIV-1 infection on the intestinal microbiome and its association with mucosal T-cell and dendritic cell (DC) frequency and activation, as well as with levels of systemic T-cell activation, inflammation, and microbial translocation. Bacterial 16S ribosomal DNA sequencing was performed on colon biopsies and fecal samples from subjects with chronic, untreated HIV-1 infection and uninfected control subjects. Colon biopsies of HIV-1-infected subjects had increased abundances of Proteobacteria and decreased abundances of Firmicutes compared with uninfected donors. Furthermore at the genus level, a significant increase in Prevotella and decrease in Bacteroides was observed in HIV-1-infected subjects, indicating a disruption in the Bacteroidetes bacterial community structure. This HIV-1-associated increase in Prevotella abundance was associated with increased numbers of activated colonic T cells and myeloid DCs. Principal coordinates analysis demonstrated an HIV-1-related change in the microbiome that was associated with increased mucosal cellular immune activation, microbial translocation, and blood T-cell activation. These observations suggest that an important relationship exists between altered mucosal bacterial communities and intestinal inflammation during chronic HIV-1 infection.

Synthesis and structural study of precursors of novel methylsilanediols by IR and Raman spectroscopies, single-crystal X-ray diffraction and DFT calculations

On the way towards the development of a synthetic route aimed at obtaining new methylsilanediol derivatives with an aminocarbonyl group in β to silicon (which may have a potential biological interest), we have synthesized, isolated and purified five diphenylic possible precursors, namely chloromethyl(methyl)diphenylsilane, 2-{[methyl(diphenyl)silyl]methyl}-1H-isoindole-1,3(2H)-dione, N-[(methyl(diphenyl) silanyl)-methyl]-benzamide, N-[(methyl(diphenyl)silyl)-methyl]-acetamide and N-[(methyl(diphenyl)silyl)-methyl]-formamide. The conformational landscape of the five species in this study are explored by means of DFT calculations at the B3LYP/6-311++G(∗∗) level. The theoretical molecular structures predicted are confirmed by the reproduction of their respective IR and Raman spectral profiles, that are completely assigned. Some evidence in the vibrational spectra points to the occurrence of conformational mixtures in the samples. Further, single-crystal X-ray diffraction has allowed the elucidation of the crystalline structure of 2-{[methyl(diphenyl)silyl]methyl}-1H-isoindole-1,3(2H)-dione.

Impaired plasmacytoid dendritic cell maturation and differential chemotaxis in chronic hepatitis C virus: associations with antiviral treatment outcomes

BACKGROUND

Dendritic cell (DC) defects may contribute to chronicity in hepatitis C virus (HCV) infection and determine response to PEG-interferon and ribavirin therapy via poor T cell stimulation. Studies to date have produced inconsistent results regarding DC maturation and function: no large study has examined DCs before and after therapy.

AIMS

We examined if DC defects in maturation and chemotaxis are present by comparing therapeutic responders to non-responders.

METHODS

We analysed peripheral DCs of 64 HCV genotype 1-infected patients from the Virahep-C study 2 weeks before and 24 weeks after therapy. We used flow cytometry to enumerate plasmacytoid DC (pDC) and myeloid DCs (mDC) and quantify expression of chemokine receptors and maturation markers. Chemotaxis was measured with an in vitro assay.

RESULTS

Pre-treatment frequencies of pDCs and mDCs were significantly lower in HCV patients than controls and successful therapy normalised pDCs. Levels of CXCR3 and CXCR4 on pDCs were higher at baseline compared to normal controls and decreased with therapy. Pre-therapy levels of co-stimulatory marker CD40 and the maturation marker CD83 were higher in pDCs of patients chronically infected with HCV compared to normal patients, and levels of both markers dropped significantly with therapy in the SVR+ group only. Other maturation markers (CD86 and CCR7) were not elevated suggesting a partially activated phenotype. Baseline chemotaxis of pDCs to CXCL12 and CXCL10 predicted failure of antiviral response and correlated with the histological activity index inflammation score.

CONCLUSIONS

Plasmacytoid DC defects exist in chronic HCV and successful antiviral therapy normalises many phenotypic and functional abnormalities.

Configurational and conformational classification of pyranose sugars

Automated cluster analysis is used to examine the conformation and configuration of pyranose sugars. Previous findings on this issue are confirmed, importantly from an analysis that requires no prior knowledge of the significant factors determining the conformational classification. The findings on the conformations adopted in the crystalline solid state are found to be different to existing quantum chemical calculations performed for D-glucose in the gas phase, but consistent with empirically determined conformations in the solution state. The use of this clustering analysis in studying chirality in the determined structures is discussed, as is the ability of this type of method to examine higher dimensions within the metric multi-dimensional scaling formalism.

Mitochondrial DNA identification of game and harvested freshwater fish species

The use of DNA in forensics has grown rapidly for human applications along with the concomitant development of bioinformatics and demographic databases to help fully realize the potential of this molecular information. Similar techniques are also used routinely in many wildlife cases, such as species identification in food products, poaching and the illegal trade of endangered species. The use of molecular techniques in forensic cases related to wildlife and the development of associated databases has, however, mainly focused on large mammals with the exception of a few high-profile species. There is a need to develop similar databases for aquatic species for fisheries enforcement, given the large number of exploited and endangered fish species, the intensity of exploitation, and challenges in identifying species and their derived products. We sequenced a 500bp fragment of the mitochondrial cytochrome b gene from representative individuals from 26 harvested fish taxa from Ontario, Canada, focusing on species that support major commercial and recreational fisheries. Ontario provides a unique model system for the development of a fish species database, as the province contains an evolutionarily diverse array of freshwater fish families representing more than one third of all freshwater fish in Canada. Inter- and intraspecific sequence comparisons using phylogenetic analysis and a BLAST search algorithm provided rigorous statistical metrics for species identification. This methodology and these data will aid in fisheries enforcement, providing a tool to easily and accurately identify fish species in enforcement investigations that would have otherwise been difficult or impossible to pursue.

Shared decision making and the experience of partnership in primary care

PURPOSE

Communication has been researched either as a set of behaviors or as a facet of the patient-physician relationship, often leading to conflicting results. To determine the relationship between these perspectives, we examined shared decision making (SDM) and the subjective experience of partnership for patients and physicians in primary care.

METHODS

From a convenience sample of experienced primary care physicians in 3 clinics, we recruited a stratified sample of 18 English- or Spanish-speaking patients. Direct observation of visits was followed by videotape-triggered stimulated recall sessions with patients and physicians. We coded decision moments for objective evidence of SDM, using a structured instrument. We classified patients' and physicians' subjective experience of partnership as positive or negative by a consensus analysis of stimulated recall sessions. We combined results from these 2 analyses to generate 4 archetypes of engagements and used grounded theory to identify themes associated with each archetype.

RESULTS

The 18 visits yielded 125 decisions, 62 (50%) of which demonstrated SDM. Eighty-two decisions were discussed in stimulated recall and available for combined analysis, resulting in 4 archetypes of engagement in decision making: full engagement (SDM present, subjective experience positive)--22%; simulated engagement (SDM present, subjective experience negative)--38%; assumed engagement (SDM absent, subjective experience positive)--21%; and nonengagement (SDM absent, subjective experience negative)--19%. Thematic analysis revealed that both relationship factors (eg, trust, power) and communication behavior influenced subjective experience of partnership.

CONCLUSIONS

Combining direct observation and assessment of the subjective experience of partnership suggests that communication behavior does not ensure an experience of collaboration, and a positive subjective experience of partnership does not reflect full communication. Attempts to enhance patient-physician partnership must attend to both effective communication style and affective relationship dynamics.

Physician notification of their diabetes patients' limited health literacy. A randomized, controlled trial

BACKGROUND

Many patients with chronic disease have limited health literacy (HL). Because physicians have difficulty identifying these patients, some experts recommend instituting screening programs in clinical settings. It is unclear if notifying physicians of patients' limited HL improves care processes or outcomes.

OBJECTIVE

To determine whether notifying physicians of their patients' limited HL affects physician behavior, physician satisfaction, or patient self-efficacy.

DESIGN

We screened all patients for limited HL and randomized physicians to be notified if their patients had limited HL skills.

PARTICIPANTS

Sixty-three primary care physicians affiliated with a public hospital and 182 diabetic patients with limited HL.

MEASUREMENTS

After their visit, physicians reported their management strategies, satisfaction, perceived effectiveness, and attitudes toward HL screening. We also assessed patients' self-efficacy, feelings regarding HL screening's usefulness, and glycemic control.

RESULTS

Intervention physicians were more likely than control physicians to use management strategies recommended for patients with limited HL (OR 3.2, P=.04). However, intervention physicians felt less satisfied with their visits (81% vs 93%, P=.01) and marginally less effective (38% vs 53%, P=.10). Intervention and control patients' post-visit self-efficacy scores were similar (12.6 vs 12.9, P=.6). Sixty-four percent of intervention physicians and 96% of patients felt HL screening was useful.

CONCLUSIONS

Physicians are responsive to receiving notification of their patients' limited HL, and patients support the potential utility of HL screening. However, instituting screening programs without specific training and/or system-wide support for physicians and patients is unlikely to be a powerful tool in improving diabetes outcomes.

Physician notification of their diabetes patients' limited health literacy. A randomized, controlled trial

BACKGROUND

Many patients with chronic disease have limited health literacy (HL). Because physicians have difficulty identifying these patients, some experts recommend instituting screening programs in clinical settings. It is unclear if notifying physicians of patients' limited HL improves care processes or outcomes.

OBJECTIVE

To determine whether notifying physicians of their patients' limited HL affects physician behavior, physician satisfaction, or patient self-efficacy.

DESIGN

We screened all patients for limited HL and randomized physicians to be notified if their patients had limited HL skills.

PARTICIPANTS

Sixty-three primary care physicians affiliated with a public hospital and 182 diabetic patients with limited HL.

MEASUREMENTS

After their visit, physicians reported their management strategies, satisfaction, perceived effectiveness, and attitudes toward HL screening. We also assessed patients' self-efficacy, feelings regarding HL screening's usefulness, and glycemic control.

RESULTS

Intervention physicians were more likely than control physicians to use management strategies recommended for patients with limited HL (OR 3.2, P=.04). However, intervention physicians felt less satisfied with their visits (81% vs 93%, P=.01) and marginally less effective (38% vs 53%, P=.10). Intervention and control patients' post-visit self-efficacy scores were similar (12.6 vs 12.9, P=.6). Sixty-four percent of intervention physicians and 96% of patients felt HL screening was useful.

CONCLUSIONS

Physicians are responsive to receiving notification of their patients' limited HL, and patients support the potential utility of HL screening. However, instituting screening programs without specific training and/or system-wide support for physicians and patients is unlikely to be a powerful tool in improving diabetes outcomes.

Discordance between frequency of human immunodeficiency virus type 1 (HIV-1)-specific gamma interferon-producing CD4(+) T cells and HIV-1-specific lymphoproliferation in HIV-1-infected subjects with active viral replication

One hallmark of uncontrolled, chronic human immunodeficiency virus type 1 (HIV-1) infection is the absence of strong HIV-1-specific, CD4(+) T-cell-proliferative responses, yet the mechanism underlying this T helper (Th)-cell defect remains controversial. To better understand the impact of HIV-1 replication on Th-cell function, we compared the frequency of CD4(+) Th-cell responses based on production of gamma interferon to lymphoproliferative responses directed against HIV-1 proteins in HIV-1-infected subjects with active in vivo viral replication versus those on suppressed highly active antiretroviral therapy (HAART). No statistically significant differences in the frequencies of cytokine-secreting, HIV-1-specific CD4(+) T cells between the donor groups were found, despite differences in viral load and treatment status. However, HIV-1-specific lymphoproliferative responses were significantly greater in the subjects with HAART suppression than in subjects with active viral replication. Similar levels of HIV-1 RNA were measured in T-cell cultures stimulated with HIV-1 antigens regardless of donor in vivo viral loads, but only HIV-1-specific CD4(+) T cells from subjects with HAART suppression proliferated in vitro, suggesting that HIV-1 replication in vitro does not preclude HIV-1-specific lymphoproliferation. This study demonstrates a discordance between the frequency and proliferative capacity of HIV-1-specific CD4(+) T cells in subjects with ongoing in vivo viral replication and suggests that in vivo HIV-1 replication contributes to the observed defect in HIV-1-specific CD4(+) T-cell proliferation.

Crystal engineering in the gem-alkynol family: the key role of water in the structure of 2,3,5,6-tetrabromo-trans-1,4-diethynyl-cyclohexa-2,5-diene-1,4-diol dihydrate determined by X-ray and neutron diffraction at 150 K

The structure of the title compound has been determined using low-temperature (150 K) single-crystal X-ray and neutron diffraction data. Crystals adopt the uncommon space group P4(2)/ncm and display a complex set of intermolecular interactions in which the water molecules play the crucial role: the water O-atom [O2(w)] accepts two hydrogen bonds and both water H atoms act as bifurcated donors. A set of O--H...O hydrogen bonds is formed around the 4(2) axis comprising (a) a cyclic tetrameric synthon involving four donor-H from two water molecules and two O(hydroxy) acceptors from two parent molecules, and (b) short discrete O(hydroxy)--H...O2(w) hydrogen bonds which link these tetramers along the c axis. Four Br...Br interactions [3.708 (1) A] form cyclic Br(4) tetramers around the 4 axis and are linked to the O--H...O system via O2(w)--H...Br bonds with H...Br = 2.995 (2) A. Finally, the O--H...O system is further linked to the parent molecules via C identical with C...H...O2(w) bonds of 2.354 (3) A. The supramolecular structure of the title hydrate is compared with that of the non-hydrated parent molecule, which also forms cyclic O--H...O bonded tetrameric synthons, and with its (non-hydrated) tetrachloro analogue, which forms cyclic tetrameric Cl(4) synthons [Madhavi, Desiraju et al. (2000b). Acta Cryst. B56, 1063--1070].

Migration of the proton in the strong O—H...O hydrogen bond in urea–phosphoric acid (1/1)

The structure of urea–phosphoric acid is reported at a large number of temperatures in the range 150–335 K from neutron diffraction data collected using a novel multiple single-crystal data collection method. The work focuses on the behaviour of the H atom involved in the short strong O—H...O hydrogen bond in this material. The position of this atom is shown to vary significantly, by around 0.035  Å, as a function of temperature, becoming effectively centred at the highest temperatures studied. This result, only accessible due to the accurate determination of H-atom parameters by neutron diffraction, has implications for the potential governing the hydrogen bond.

Identification and antigenicity of broadly cross-reactive and conserved human immunodeficiency virus type 1-derived helper T-lymphocyte epitopes

Human immunodeficiency virus (HIV)-specific helper T lymphocytes (HTL) play a key role in the immune control of HIV type 1 (HIV-1) infection, and as such are an important target of potential HIV-1 vaccines. In order to identify HTL epitopes in HIV-1 that might serve as vaccine targets, conserved HIV-1-derived peptides bearing an HLA-DR binding supermotif were tested for binding to a panel of the most representative HLA-DR molecules. Eleven highly cross-reactive binding peptides were identified: three in Gag and eight in Pol. Lymphoproliferative responses to this panel of peptides, as well as to the HIV-1 p24 and p66 proteins, were evaluated with a cohort of 31 HIV-1-infected patients. All 11 peptides were recognized by peripheral blood mononuclear cells from multiple HIV-infected donors. Many of the responsive HIV-infected subjects showed recognition of multiple peptides, indicating that HIV-1-specific T-helper responses may be broadly directed in certain individuals. A strong association existed between recognition of the parental recombinant HIV-1 protein and the corresponding HTL peptides, suggesting that these peptides represent epitopes that are processed and presented during the course of HIV-1 infection. Lastly, responses to the supermotif peptides were mediated by CD4(+) T cells and were restricted by major histocompatibility complex class II molecules. The epitopes described herein are potentially important components of HIV-1 therapeutic and prophylactic vaccines.

Whole recombinant yeast vaccine activates dendritic cells and elicits protective cell-mediated immunity

There is currently a need for vaccines that stimulate cell-mediated immunity-particularly that mediated by CD8+ cytotoxic T lymphocytes (CTLs)-against viral and tumor antigens. The optimal induction of cell-mediated immunity requires the presentation of antigens by specialized cells of the immune system called dendritic cells (DCs). DCs are unique in their ability to process exogenous antigens via the major histocompatibility complex (MHC) class I pathway as well as in their ability to activate naive, antigen-specific CD8+ and CD4+ T cells. Vaccine strategies that target or activate DCs in order to elicit potent CTL-mediated immunity are the subject of intense research. We report here that whole recombinant Saccharomyces cerevisiae yeast expressing tumor or HIV-1 antigens potently induced antigen-specific, CTL responses, including those mediating tumor protection, in vaccinated animals. Interactions between yeast and DCs led to DC maturation, IL-12 production and the efficient priming of MHC class I- and class II-restricted, antigen-specific T-cell responses. Yeast exerted a strong adjuvant effect, augmenting DC presentation of exogenous whole-protein antigen to MHC class I- and class II-restricted T cells. Recombinant yeast represent a novel vaccine strategy for the induction of broad-based cellular immune responses.

Holarctic phylogeography of Arctic charr (Salvelinus alpinus L.) inferred from mitochondrial DNA sequences

This study evaluated mitochondrial DNA (mtDNA) sequence variation in a 552-bp fragment of the control region of Arctic charr (Salvelinus alpinus) by analyzing 159 individuals from 83 populations throughout the entire range of the complex. A total of 89 (16.1%) nucleotide positions were polymorphic, and these defined 63 haplotypes. Phylogenetic analyses supported the monophyly of the complex and assigned the observed haplotypes to five geographic regions that may be associated with different glacial refugia. Most notably, a formerly defined major evolutionary lineage (S. a. erythrinus) ranging from North America across the Arctic archipelago to the Eurasian continent has now been partitioned into the Arctic group and the newly identified Siberian group. The Beringian group, formed entirely by specimens assigned to S. malma (Dolly Varden), encompassed the area formerly assigned to S. a. taranetzi. The latter, due to a unique haplotype, became the basal member of the Arctic group. Overall, the S. alpinus complex reflects divergent evolutionary groups coupled with shallow intergroup differentiation, also indicated by an analysis of molecular variance that attributed 73.7% (P < 0.001) of the total genetic variance among groups. Time estimates, based on sequence divergence, suggest a separation of the major phylogeographic groups during early to mid-Pleistocene. In contrast, colonization of most of today's range started relatively recently, most likely late Pleistocene during the last retreat of ice sheets some 10,000-20,000 years ago. This time scale obviously is too shallow for detecting significant variation on a smaller scale using mtDNA markers. However, other studies using nuclear microsatellite DNA variation strongly suggested ongoing evolution within groups by revealing strong population-genetic substructuring and restricted gene flow among populations. Thus, Arctic charr could serve as a model organism to investigate the linkage between historical and contemporary components of phylogeographic structuring in fish, and, with a global perspective of the distribution of genetic variation as a framework, meaningful comparisons of charr studies at a smaller geographic scale will now be possible.

Delivery of liposome-encapsulated HIV type 1 proteins to human dendritic cells for stimulation of HIV type 1-specific memory cytotoxic T lymphocyte responses

An important aspect of vaccine development involves delivery of antigens to antigen-presenting cells for the induction of potent antigen-specific T lymphocyte responses. We investigated the effect of a cationic liposome, lipofectin, on delivery of whole proteins to human dendritic cells (DCs) derived from blood mononuclear cells by culture in interleukin 4 and granulocyte-monocyte colony-stimulating factor for stimulation of human immunodeficiency virus type 1 (HIV-1)-specific memory cytotoxic T lymphocyte (CTL) responses. Delivery of HIV-1 Gag, Pol, and Env proteins to DCs by lipofectin stimulated greater anti-HIV-1 memory CTL responses in cells from HIV-1-infected subjects than those induced by DCs loaded with protein alone. The CTLs were CD8+ and HLA class I restricted. Antigen presentation was enhanced by chloroquine, but blocked by brefeldin A and peptide aldehyde inhibitors of proteasomes, indicating that the classic MHC class I cytosolic pathway was used for processing and presentation of HIV-1 protein by the DCs. Stimulation of anti-HIV-1 CTLs by this safe, inexpensive, and broadly applicable approach may be used in DC-based therapies for HIV-1 infection.

Lack of viral escape and defective in vivo activation of human immunodeficiency virus type 1-specific cytotoxic T lymphocytes in rapidly progressive infection

Human immunodeficiency virus type 1 (HIV-1)-specific immune responses over the course of rapidly progressive infection are not well defined. Detailed longitudinal analyses of neutralizing antibodies, lymphocyte proliferation, in vivo-activated and memory cytotoxic T-lymphocyte (CTL) responses, and viral sequence variation were performed on a patient who presented with acute HIV-1 infection, developed an AIDS-defining illness 13 months later, and died 45 months after presentation. Neutralizing-antibody responses remained weak throughout, and no HIV-1-specific lymphocyte proliferative responses were seen even early in the disease course. Strong in vivo-activated CTL directed against Env and Pol epitopes were present at the time of the initial drop in viremia but were quickly lost. Memory CTL against Env and Pol epitopes were detected throughout the course of infection; however, these CTL were not activated in vivo. Despite an initially narrow CTL response, new epitopes were not targeted as the disease progressed. Viral sequencing showed the emergence of variants within the two targeted CTL epitopes; however, viral variants within the immunodominant Env epitope were well recognized by CTL, and there was no evidence of viral escape from immune system detection within this epitope. These data demonstrate a narrowly directed, static CTL response in a patient with rapidly progressive disease. We also show that disease progression can occur in the presence of persistent memory CTL recognition of autologous epitopes and in the absence of detectable escape from CTL responses, consistent with an in vivo defect in activation of CTL.

Frequent detection of escape from cytotoxic T-lymphocyte recognition in perinatal human immunodeficiency virus (HIV) type 1 transmission: the ariel project for the prevention of transmission of HIV from mother to infant

Host immunologic factors, including human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL), are thought to contribute to the control of HIV type 1 (HIV-1) replication and thus delay disease progression in infected individuals. Host immunologic factors are also likely to influence perinatal transmission of HIV-1 from infected mother to infant. In this study, the potential role of CTL in modulating HIV-1 transmission from mother to infant was examined in 11 HIV-1-infected mothers, 3 of whom transmitted virus to their offspring. Frequencies of HIV-1-specific human leukocyte antigen class I-restricted CTL responses and viral epitope amino acid sequence variation were determined in the mothers and their infected infants. Maternal HIV-1-specific CTL clones were derived from each of the HIV-1-infected pregnant women. Amino acid substitutions within the targeted CTL epitopes were more frequently identified in transmitting mothers than in nontransmitting mothers, and immune escape from CTL recognition was detected in all three transmitting mothers but in only one of eight nontransmitting mothers. The majority of viral sequences obtained from the HIV-1-infected infant blood samples were susceptible to maternal CTL. These findings demonstrate that epitope amino acid sequence variation and escape from CTL recognition occur more frequently in mothers that transmit HIV-1 to their infants than in those who do not. However, the transmitted virus can be a CTL susceptible form, suggesting inadequate in vivo immune control.

HIV-1-specific CTL responses primed in vitro by blood-derived dendritic cells and Th1-biasing cytokines

Vaccine strategies designed to elicit strong cell-mediated immune responses to HIV Ags are likely to lead to protective immunity against HIV infection. Dendritic cells (DC) are the most potent APCs capable of priming both MHC class I- and II-restricted, Ag-specific T cell responses. Utilizing a system in which cultured DC from HIV-seronegative donors were used as APC to present HIV-1 Ags to autologous T cells in vitro, the strength and specificity of primary HIV-specific CTL responses generated to exogenous HIV-1 Nef protein as well as intracellularly expressed nef transgene product were investigated. DC expressing the nef gene were able to stimulate Nef-specific CTL, with T cells from several donors recognizing more than one epitope restricted by a single HLA molecule. Primary Nef-specific CTL responses were also generated in vitro using DC pulsed with Nef protein. T cells primed with Nef-expressing DC (via protein or transgene) were able to lyse MHC class I-matched target cells pulsed with defined Nef epitope peptides as well as newly identified peptide epitopes. The addition of Th1-biasing cytokines IL-12 or IFN-alpha, during priming with Nef-expressing DC, enhanced the Nef-specific CTL responses generated using either Ag-loading approach. These results suggest that this in vitro vaccine model may be useful in identifying immunogenic epitopes as vaccine targets and in evaluating the effects of cytokines and other adjuvants on Ag-specific T cell induction. Successful approaches may provide information important to the development of prophylactic HIV vaccines and are envisioned to be readily translated into clinical DC-based therapeutic vaccines for HIV-1.

Autologous human monocyte-derived dendritic cells genetically modified to express melanoma antigens elicit primary cytotoxic T cell responses in vitro: enhancement by cotransfection of genes encoding the Th1-biasing cytokines IL-12 and IFN-alpha

DNA-based immunization strategies designed to elicit cellular antitumor immunity offer an attractive alternative to protein- or peptide-based approaches. In the present study we have evaluated the feasibility of DNA vaccination for the induction of CTL reactivity to five different melanoma Ags in vitro. Cultured, monocyte-derived dendritic cells (DC) were transiently transfected with plasmid DNA encoding human MART-1/Melan-A, pMel-17/gp100, tyrosinase, MAGE-1, or MAGE-3 by particle bombardment and used to stimulate autologous PBMC responder T cells. CTL reactivity to these previously identified melanoma Ags was reproducibly generated after two or three stimulations with genetically modified DC. Co-ordinate transfection of two melanoma Ag cDNAs into DC promoted CTL responders capable of recognizing epitopes from both gene products. Coinsertion of genes encoding the Th1-biasing cytokines IL-12 or IFN-alpha consistently enhanced the magnitude of the resulting Ag-specific CTL reactivity. Importantly, DC transfected with a single melanoma Ag cDNA were capable of stimulating Ag-specific CTL reactivity restricted by multiple host MHC alleles, some of which had not been previously identified. These results support the inherent strengths of gene-based vaccine approaches that do not require prior knowledge of responder MHC haplotypes or of relevant MHC-restricted peptide epitopes. Given previous observations of in situ tumor HLA allele-loss variants, DC gene vaccine strategies may elicit a greater diversity of host therapeutic immunity, thereby enhancing the clinical utility and success of such approaches.

Serotonin regulates synaptic connections in the dentate molecular layer of adult rats via 5-HT1a receptors: evidence for a glial mechanism

The present study sought to verify effects of 5-HT on synaptic density at the ultrastructural level, to determine whether the 5-HT1a receptor is important for the maintenance of synaptic connections and to obtain evidence implicating S100 beta in the apparent neurotrophic actions of 5-HT. Reduction of hippocampal 5-HT with para-chloroamphetamine (PCA) resulted in a significant decline in the synaptic density of the dentate molecular layer. Reduction of norepinephrine with DSP-4 produced a slight decrease in the number of molecular layer synapses, but this difference was not statistically different from control values. 5-HT1a antagonist treatment resulted in a decline in synaptic density comparable to that observed following PCA treatment. These observations suggest that 5-HT functions to maintain synaptic connections in the dentate molecular layer via a 5-HT1a mechanism. To determine whether the change in synaptic density was due to the action of 5-HT on neuronal receptors or astrocytic receptors, a monoclonal antibody against S100 beta was infused into the lateral ventricle for seven days. Controls received infusions of normal goat serum. Half of the rats from the anti-S100 beta and control groups also received daily injections of NAN-190. Anti-S100 beta infusion resulted in a significant (p < 0.01) decrease in synapses compared to serum controls. Concomitant NAN-190 administration did not enhance synapse loss in the anti-S100 beta group. The results of this study suggest that the maintenance of synaptic connections in the dentate molecular layer is influenced by S100 beta levels that are controlled by 5-HT stimulation of astrocytic 5-HT1a receptors.

Effects of neonatal serotonin depletion on the development of rat dentate granule cells

The appearance of serotonergic (5-HT) neurons and projections early in central nervous system (CNS) development has resulted in the hypothesis that 5-HT is an important factor in neuronal differentiation and synaptogenesis. Studies of the effects of 5-HT on the development of molluscan and mammalian neurons in vitro support this hypothesis, but mammalian in vivo studies have produced equivocal results. The present study reinvestigated the role of 5-HT in CNS development using the dentate granule cell as a model. Dentate granule cells were chosen for this study of the effects of 5-HT depletion on neuronal development because they are generated in the early postnatal period. Thus, 5-HT depletion could be effected by the treatment of rat pups with either parachloroamphetamine (PCA) or 5,7-dihydroxytryptamine (5,7-DHT) thereby avoiding problems inherent in maternal treatment paradigms. The morphology of Neurobiotin-filled granule cells was studied on P14, P21, P60 and P120 (P0 = day of birth). The parameters measured were total dendritic length, number of dendritic segments and dendritic spine density (number of spines/50 microns dendritic length). Granule cells from vehicle-treated controls were similar to those previously reported in studies of normal granule cell development in all respects. In particular, the decrease in dendritic spine density from P14 to P120 observed in Golgi preparations was verified in our population of intracellularly filled granule cells. Transient depletion of 5-HT by neonatal PCA treatment resulted in a decrease dendritic length that was not statistically different from control values. However, dendritic spine density was reduced by about 27% at all ages studied. 5,7-DHT treatment produces a permanent, severe depletion of 5-HT. Spine densities in granule cells from 5,7-DHT-treated pups were also about 38% lower than controls. Total dendritic length in cells from 5,7-DHT-treated rats was reduced to a degree comparable to that observed in PCA-treated pups. The number of granule cell dendritic segments was also less than that observed in control and PCA-treated rats but this difference was not statistically significant. These observations suggest that reduction of 5-HT in the early postnatal period can result in changes in the morphology of dentate granule cells, particularly at the level of the synapse as reflected by the permanent reduction in synaptic spine density. The comparison of results from cases with permanent and transient reduction of 5-HT indicates that the developmental influence of 5-HT is most important during the first three postnatal weeks.

5-HT1a receptors mediate the neurotrophic effect of serotonin on developing dentate granule cells

We have previously reported that neonatal (P3) serotonin (5-HT) depletion results in a significant decrease in the number of dendritic spines per 50 microns of dendritic length on dentate granule cells. This effect is specific and permanent. Neither total dendritic length nor the number of dendritic segments is affected by 5-HT depletion. The area dentata contains a dense 5-HT1a receptor population that is present in the at birth. Therefore, 5-HT1a receptors represented a likely candidate for the mediation of the effects of 5-HT on developing granule cells. The present study used the drugs buspirone and NAN-190, which have been shown to be an agonist and antagonist respectively at postsynaptic 5-HT1a receptors in vivo, to test the idea that neurotrophic actions of 5-HT result from 5-HT1a receptor stimulation. Following 5-HT depletion with PCA, pups received daily injections of buspirone (1.0 mg/kg) from P5 to P14. Granule cell morphology was then studied using intracellular filling with Neurobiotin on P14, P21 and P60. Buspirone treatment prevented the loss of dendritic spines previously shown to follow 5-HT depletion with PCA. No other morphological parameters were significantly changed by buspirone treatment. Naive pups received daily injections of NAN-190 from P3 to P14. One group received 1.0 mg/kg while a second group received 3.5 mg/kg. Both doses of NAN-190 resulted in dendritic spine loss comparable to that obtained with neonatal PCA treatment. This loss was permanent suggesting that the first two postnatal weeks may represent a critical period for the action of 5-HT on developing granule cells. Significant, dose-dependent changes in total dendritic length and number of dendritic segments reminiscent of the effects of norepinephrine depletion were also observed in NAN-190-treated rats. We suspect that this change is the result of the action NAN-190 at alpha receptors and is therefore distinct from the specific effect of 5-HT on the number of dendritic spines. The NAN-190 experiment also shows that the loss of dendritic spines is a function of decreased stimulation of 5-HT1a receptors and not the loss of 5-HT terminal membrane.

Overlapping epitopes in human immunodeficiency virus type 1 gp120 presented by HLA A, B, and C molecules: effects of viral variation on cytotoxic T-lymphocyte recognition

Human immunodeficiency virus (HIV)-specific cytotoxic T lymphocytes (CTL) are thought to exert immunologic selection pressure in infected persons, yet few data regarding the effects of this constraint on viral sequence variation in vivo, particularly in the highly variable Env protein, are available. In this study, CD8+ HIV type 1 (HIV-1) envelope-specific CTL clones specific for gp120 were isolated from peripheral blood mononuclear cells of four HIV-infected individuals, all of which recognized the same 25-amino-acid (aa) peptide (aa 371 to 395), which is partially contained in the CD4-binding domain of HIV-1 gp120. Fine mapping studies revealed that two of the clones optimally recognized the 9-aa sequence 375 to 383 (SFNCGGEFF), while the two other clones optimally recognized the epitope contained in the overlapping 9-aa sequence 376 to 384 (FNCGGEFFY). Lysis of target cells by the two clones recognizing aa 375 to 383 was restricted by HLA B15 and Cw4, respectively, whereas both clones recognizing aa 376 to 384 were restricted by HLA A29. Sequence variation, relative to the IIIB strain sequence used to identify CTL clones, was observed in autologous viruses in the epitope-containing region in all four subjects. However, poorly recognized autologous sequence variants were predominantly seen for the A29-restricted clones, whereas the clones specific for SFNCGGEFF continued to recognize the predominant autologous sequences. These results suggest that the HLA profile of an individual may not only be important in determining the specificity of CTL recognition but may also affect the ability to recognize virus variants and suppress escape from CTL recognition. These results also identify overlapping viral CTL epitopes which can be presented by HLA A, B, and C molecules.

Time-of-flight Laue fiber diffraction studies of perdeuterated DNA

The diffractometer SXD at the Rutherford Appleton Laboratory ISIS pulsed neutron source has been used to record high resolution time-of-flight Laue fiber diffraction data from DNA. These experiments, which are the first of their kind, were undertaken using fibers of DNA in the A conformation and prepared using deuterated DNA in order to minimise incoherent background scattering. These studies complement previous experiments on instrument D19 at the Institut Laue Langevin using monochromatic neutrons. Sample preparation involved drawing large numbers of these deuterated DNA fibers and mounting them in a parallel array. The strategy of data collection is discussed in terms of camera design, sample environment and data collection. The methods used to correct the recorded time-of-flight data and map it into the final reciprocal space fiber diffraction dataset are also discussed. Difference Fourier maps showing the distribution of water around A-DNA calculated on the basis of these data are compared with results obtained using data recorded from hydrogenated A-DNA on D19. Since the methods used for sample preparation, data collection and data processing are fundamentally different for the monochromatic and Laue techniques, the results of these experiments also afford a valuable opportunity to independently test the data reduction and analysis techniques used in the two methods.

DNA hydration studied by neutron fiber diffraction

The development of neutron high angle fiber diffraction to investigate the location of water around the deoxyribonucleic acid (DNA) double-helix is described. The power of the technique is illustrated by its application to the D and A conformations of DNA using the single crystal diffractometer, D19, at the Institut Laue-Langevin. Grenoble and the time of flight diffractometer, SXD, at the Rutherford Appleton ISIS Spallation Neutron Source. These studies show the existence of bound water closely associated with the DNA. The patterns of hydration in these two DNA conformations are quite distinct and are compared to those observed in X-ray single crystal studies of two-stranded oligodeoxynucleotides. Information on the location of water around the DNA double-helix from the neutron fiber diffraction studies is combined with that on the location of alkali metal cations from complementary X-ray high angle fiber diffraction studies at the Daresbury Laboratory SRS using synchrotron radiation. These analyses emphasize the importance of viewing DNA, water and ions as a single system with specific interactions between the three components and provide a basis for understanding the effect of changes in the concentration of water and ions in inducing conformational transitions in the DNA double-helix.

Hydrogen-Atom Ordering in Lead Hydrogen Arsenate Monitored by Neutron Time-of-Flight Laue Diffraction using Single-Frame Methods

The ordering of the hydrogen atom in a single crystal of lead hydrogen arsenate in the temperature range 320 to 80 K is described. The details of the ordering at small temperature steps are determined from single frames of data collected using the neutron time-of-flight Laue method. The constrained refinements obtained from these data yield lower precision than full data sets but allow the ordering to be characterized rapidly and reliably. This is the first example of the use of this single-frame method of monitoring such phase transitions. The approach used here with neutrons, stimulated in part by synchrotron Laue diffraction, will be of interest for all time-resolved experiments with synchrotron radiation or neutrons.

Ex vivo expansion of CD4 lymphocytes from human immunodeficiency virus type 1-infected persons in the presence of combination antiretroviral agents

Expansion of CD4 lymphocytes from human immunodeficiency virus type 1 (HIV-1)-infected persons ex vivo has been limited by enhanced virus replication and cell death. The successful expansion of functional CD4 lymphocytes from HIV-1-infected persons has now been accomplished using a bispecific monoclonal antibody to CD3 and CD8 in combination with three antiretroviral agents. CD4 lymphocytes were polyclonally expanded by a factor of 10(3)-10(7) during 4-8 weeks in culture. Supernatants from most cultures were persistently HIV-1 p24 antigen-negative by day 14 and remained negative despite removal of antiretroviral agents at day 28. In such cultures, HIV-1 could not be recovered by cocultivation, and amounts of HIV-1 DNA declined or remained stable at low levels, eventually becoming undetectable in 2 cases. This approach establishes the feasibility of CD4 lymphocyte expansion in persons with HIV disease and may be useful for immune-based or gene therapies.

Transient reduction in hippocampal serotonergic innervation after neonatal parachloroamphetamine treatment

This study examined the effects of parachloroamphetamine on neonatal forebrain serotonergic (5-HT) innervation. Rat pups were treated with PCA on P3 and P4. Significant reductions in 5-HT content were observed in the hippocampal formation, frontal cortex and entorhinal cortex on P5 and P7. By P14, neocortical 5-HT had returned to normal levels while hippocampal 5-HT values remained less than control. Hippocampal 5-HT content reached normal range by P21. High affinity 5-HT uptake in hippocampal synaptosomal preparations was similarly reduced on P5 and P7 suggesting that 5-HT terminals were being lesioned by PCA. 5-HT uptake recovered significantly by P14 perhaps reflecting the extraordinary plasticity of the 5-HT projections in the neonate. However, in contrast to the complete restoration of hippocampal 5-HT content, 5-HT uptake values remained significantly less than control. No change in 5-HT content was observed in either the hypothalamus or midbrain raphe at any age studied. Thus, the rapid onset of effects, regional selectivity and transient reduction of 5-HT levels recommend the use of PCA in studies of the role of 5-HT in hippocampal development.

Calcium channel blockers in the treatment of hypertension

Physicians need to weigh the efficacy, adverse effects and cost of first-line antihypertensive agents. Calcium channel blockers lower blood pressure, improve coronary blood flow and depress cardiac contractility by relaxing smooth muscle and cardiac muscle. They have beneficial or neutral effects in hypertensive patients with angina, asthma, chronic obstructive pulmonary disease, postural hypotension, peripheral vascular disease, depression, sexual dysfunction, diabetes and hyperlipidemia. The major adverse effect of some calcium channel blockers is that they may worsen congestive heart failure in some patients. Because calcium channel blockers are metabolized in the liver, the dosage must be lowered in the elderly and in patients with hepatic disease. Diltiazem, verapamil and nifedipine represent prototypes of the three classes of calcium channel blockers, each with slightly different effects.

State unit on aging involvement with continuing care retirement community (CCRC) legislation

State units on aging (SUAs) from 29 states with continuing care retirement community (CCRC) legislation were surveyed to (a) assess staff familiarity with CCRC legislation, (b) examine interdepartmental working relationships surrounding such legislation and ask what role(s) ombudspersons are playing in CCRC oversight, (c) determine what role(s) aging units have had in developing legislation, and (d) gain insights regarding legislative impact. Results indicate that SUAs have been active in legislative development but vary greatly in the intensity of their involvement with the implementation and enforcement of CCRC regulation and in their perception of legislative impact.

The pet as an anxiolytic intervention

The effect of a pet on psychological consequences of stress (i.e., state and trait anxiety levels) of college students was examined under three test conditions (i.e., reading aloud, reading quietly, and interacting with a friendly but unknown dog). A repeated-measures analysis of variance with three covariates was used to examine the effect of the treatment on each dependent variable (state and trait anxiety). Reading aloud differed from baseline measure under all treatment conditions (p less than .001). Reading quietly and interacting with the dog were slightly below baseline for variables, with more effect seen by reading quietly than by interacting with the dog. Examination of interactions among variables showed no significant differences. Effects upon state anxiety were significant, while trait anxiety levels remained fairly constant throughout the treatments. Baseline differences in trait anxiety scores indicate a potentially greater benefit for pet owners than nonowners. Selected social network and relationship data related to the role of the pet during anxiety-producing times were also analyzed. While interaction with the pet produced a decrease in anxiety level, pet owners did not report the use of their own pet as a social support (i.e., as confidant) significantly more than did previous owners. Results indicated that interacting with a pet for some individuals does affect both physiological and psychological responses by lowering response levels. However, a parallel effect was also seen by reading quietly. Given the effect of pet interaction upon selected social support indicators of health in well college students, these data suggest the importance of examining this treatment with an "at-risk" group in which it is possible to control for ownership characteristics.

CCRC statutes: the oversight of long-term care service delivery

A 1987 national survey revealed 27 states with continuing care or life care legislation. State oversight staff in 22 states responded to questions concerning characteristics of the regulated continuing care retirement community (CCRC) industry, the regulation of health and human service delivery within CCRCs, and interdepartmental working relationships between oversight agencies and other state units. Discussion focuses on the regulation of long-term care service provision in the CCRC industry.

Lessons from the implementation of CCRC regulation

Oversight staff in 23 of the 30 states with legislation regulating continuing care retirement communities (CCRCs) completed a questionnaire surveying features of implementation experience such as problems encountered with the scope of regulation, the appropriateness of oversight placement, the adequacy of staff and financial resources, the use of discretionary agency authority, and attitudes toward various changes in applicable state law. These findings have relevance for consumers, legislators, lobbyists, and professionals working to make CCRCs a responsible long-term care alternative.

Psychogenic amnesia

Psychogenic amnesia is a psychiatric disorder characterized by sudden loss of memory in the absence of organic lesion or disease. The disorder most frequently occurs in association with a severe stressor, such as a natural disaster or military conflict. To facilitate effective treatment and an accurate prognosis, psychogenic amnesia must be differentiated from amnesia of structural or pharmacologic origin. Treatment may involve supportive psychotherapy, behavioral modification or pharmacotherapy. Prognosis for complete recovery is generally good.

Analysis of conformational parameters in nucleic acid fragments. IV. Intercalating drug complexes of very short chain oligonucleotides

Studies have been made of base-pairing conformational parameters in single crystal structures of very short chain oligonucleotide structures complexed with drug molecules, using data extracted from the Cambridge structural database. The planar portion of the drug has a tendency to intercalate between two bases, utilising strong stacking interactions to stabilise the configuration. The effect of the existence of a formative backbone is seen in the high occurrence of standard base-pairing schemes and a consistent C1'-C1' separation, although the choice of compounds studied does tend to emphasise complementary pairing. In addition to the modulation of the general magnitude which is reduced from that in uncomplexed oligonucleotides, there appears to be some correlation of propeller twist value with the presence of planar groups sandwiching a base-pair. The average twist in such sandwiched pairs is lower than in any other group studied to date.

Analysis of conformational parameters in nucleic acid fragments. III. Very short chain oligonucleotides. The effect of base stacking

Studies have been made of conformational parameters in single crystal structures of very short chain oligonucleotides consisting of strands with lengths in the range 2-3 bases. Using published data extracted from the Cambridge structural database for 20 such structures, a total of 14 base-pairs were found, of which 10 were hetero-pairs and 4 homo-pairs. Subjecting these to analysis to examine hydrogen bond parameters, propeller twist, buckle and C1'-C1' separation revealed an average propeller twist of 11.6 degrees, with no dependence of this parameter on hydrogen bonding details. In addition, an analysis of base stacking showed there to be no correlation between in-plane geometry and degree of inter-plane overlap.

State screening for metabolic disorders in newborns

Most states have mandatory screening programs for congenital and inherited disorders of metabolism. Physicians may be unaware of their state's requirements, and compiled lists of testing requirements are generally unavailable or incomplete. All states test for congenital hypothyroidism and phenylketonuria. Some states require that newborns be tested for up to six other specific congenital and inherited disorders of metabolism. Some states base their decision to test on demographic data, but there is no uniformity in the tests.