Salmon hatchery strays can demographically boost wild populations at the cost of diversity: quantitative genetic modelling of Alaska pink salmon.

Hatcheries are vital to many salmon fisheries, with inherent risks and rewards. While hatcheries can increase the returns of adult fish, the demographic and evolutionary consequences for natural populations interacting with hatchery fish on spawning grounds remain unclear. This study examined the impacts of stray hatchery-origin pink salmon on natural population productivity and resilience. We explored temporal assortative mating dynamics using a quantitative genetic model that assumed the only difference between hatchery- and natural-origin adults was their return timing to natural spawning grounds. This model was parameterized with empirical data from an intensive multi-generational study of hatchery-wild interactions in the world's largest pink salmon fisheries enhancement program located in Prince William Sound, Alaska. Across scenarios of increasing hatchery fish presence on spawning grounds, our findings underscore a trade-off between demographic enhancement and preservation of natural population diversity. While enhancement bolstered natural population sizes towards local carrying capacities, hatchery introgression reduced variation in adult return timing by up to 20%. Results indicated that hatchery-origin alleles can rapidly assimilate into natural populations, despite the reduced fitness of hatchery fish attributable to phenotypic mismatches. These findings elucidate the potential for long-term demographic and evolutionary consequences arising from specific hatchery-wild interactions, emphasizing the need for management strategies that balance demographic enhancement with the conservation of natural diversity.

A Covalent and Modular Synthesis of Homo- and Hetero[n]rotaxanes.

Incorporation of 2,5-dihydroxyterephthalate as a covalent scaffold in the axis of a 30-membered all-carbon macrocycle provides access to a modular series of rotaxanes. Installment of tethered alkynes or azides onto the terephthalic phenolic hydroxyl functionalities, which are situated at opposite sides of the macrocycle, gives versatile prerotaxane building blocks. The corresponding [2]rotaxanes are obtained by introduction of bulky stoppering ("capping") units at the tethers and subsequent cleavage of the covalent ring/thread ester linkages. Extension of this strategy via coupling of two prerotaxanes bearing complementary linker functionalities (i.e., azide and alkyne) and follow-up attachment of stopper groups provide efficient access to [n]rotaxanes. The applicability and modular nature of this novel approach were demonstrated by the synthesis of a series of [2]-, [3]-, and [4]rotaxanes. Furthermore, it is shown that the prerotaxanes allow late-stage functionalization of the ring fragment introducing further structural diversity.

Local adaptation of phenology revealed in outcrosses between spawning segments of a salmonid population.

Local adaptation has been demonstrated in spatially or temporally distant animal populations but seldom in proximate populations. To address the scale of local adaptation in Pacific salmon (Oncorhynchus spp.), two generations of hybrids between temporally separated spawning segments were made in a population of pink salmon (O. gorbuscha) and compared with controls to evaluate the genetic architecture underlying adult migration time and to test for declines in marine survival that resulted from outbreeding depression. Bayesian mixed-effects models revealed that adult migration times in hybrid lines were intermediate to those of controls and that additive sources of genetic variation were significant, thereby indicating that local adaptation has acted on additive genetic variation in shaping this trait. Similarly, a line cross analysis revealed that an additive model best described the genetic architecture of adult migration time. In contrast, marine survival was generally similar between control and hybrid lines, which suggested that the effect of outbreeding upon marine survival was minimal at such a fine scale of genetic divergence. The implications of these results are that (a) local adaptation can facilitate genetic divergence of life history traits between proximate subpopulations; (b) artificial relaxation of natural barriers to gene flow can cause maladaptive shifts in life history traits; and (c) wild populations may harbour fine-scale adaptive variation that supports productivity and sustainability.

Signals of large scale climate drivers, hatchery enhancement, and marine factors in Yukon River Chinook salmon survival revealed with a Bayesian life history model.

Understanding how species might respond to climate change involves disentangling the influence of co-occurring environmental factors on population dynamics, and is especially problematic for migratory species like Pacific salmon that move between ecosystems. To date, debate surrounding the causes of recent declines in Yukon River Chinook salmon (Oncorhynchus tshawytscha) abundance has centered on whether factors in freshwater or marine environments control variation in survival, and how these populations at the northern extremity of the species range will respond to climate change. To estimate the effect of factors in marine and freshwater environments on Chinook salmon survival, we constructed a stage-structured assessment model that incorporates the best available data, estimates incidental marine bycatch mortality in trawl fisheries, and uses Bayesian model selection methods to quantify support for alternative hypotheses. Models fitted to two index populations of Yukon River Chinook salmon indicate that processes in the nearshore and marine environments are the most important determinants of survival. Specifically, survival declines when ice leaves the Yukon River later in the spring, increases with wintertime temperature in the Bering Sea, and declines with the abundance of globally enhanced salmon species consistent with competition at sea. In addition, we found support for density-dependent survival limitations in freshwater but not marine portions of the life cycle, increasing average survival with ocean age, and age-specific selectivity of bycatch mortality in the Bering Sea. This study underscores the utility of flexible estimation models capable of fitting multiple data types and evaluating mortality from both natural and anthropogenic sources in multiple habitats. Overall, these analyses suggest that mortality at sea is the primary driver of population dynamics, yet under warming climate Chinook salmon populations at the northern extent of the species' range may be expected to fare better than southern populations, but are influenced by foreign salmon production.

Benefits and risks of diversification for individual fishers.

Individuals relying on natural resource extraction for their livelihood face high income variability driven by a mix of environmental, biological, management, and economic factors. Key to managing these industries is identifying how regulatory actions and individual behavior affect income variability, financial risk, and, by extension, the economic stability and the sustainable use of natural resources. In commercial fisheries, communities and vessels fishing a greater diversity of species have less revenue variability than those fishing fewer species. However, it is unclear whether these benefits extend to the actions of individual fishers and how year-to-year changes in diversification affect revenue and revenue variability. Here, we evaluate two axes by which fishers in Alaska can diversify fishing activities. We show that, despite increasing specialization over the last 30 years, fishing a set of permits with higher species diversity reduces individual revenue variability, and fishing an additional permit is associated with higher revenue and lower variability. However, increasing species diversity within the constraints of existing permits has a fishery-dependent effect on revenue and is usually (87% probability) associated with increased revenue uncertainty the following year. Our results demonstrate that the most effective option for individuals to decrease revenue variability is to participate in additional or more diverse fisheries. However, this option is expensive, often limited by regulations such as catch share programs, and consequently unavailable to many individuals. With increasing climatic variability, it will be particularly important that individuals relying on natural resources for their livelihood have effective strategies to reduce financial risk.

Population Trend and Elasticities of Vital Rates for Steller Sea Lions (Eumetopias jubatus) in the Eastern Gulf of Alaska: A New Life-History Table Analysis.

Steller sea lion (Eumetopias jubatus) numbers are beginning to recover across most of the western distinct population segment following catastrophic declines that began in the 1970s and ended around the turn of the century. This study makes use of contemporary vital rate estimates from a trend-site rookery in the eastern Gulf of Alaska (a sub-region of the western population) in a matrix population model to estimate the trend and strength of the recovery across this region between 2003 and 2013. The modeled population trend was projected into the future based on observed variation in vital rates and a prospective elasticity analysis was conducted to determine future trends and which vital rates pose the greatest threats to recovery. The modeled population grew at a mean rate of 3.5% per yr between 2003 and 2013 and was correlated with census count data from the local rookery and throughout the eastern Gulf of Alaska. If recent vital rate estimates continue with little change, the eastern Gulf of Alaska population could be fully recovered to pre-decline levels within 23 years. With density dependent growth, the population would need another 45 years to fully recover. Elasticity analysis showed that, as expected, population growth rate (λ) was most sensitive to changes in adult survival, less sensitive to changes in juvenile survival, and least sensitive to changes in fecundity. A population decline could be expected with only a 6% decrease in adult survival, whereas a 32% decrease in fecundity would be necessary to bring about a population decline. These results have important implications for population management and suggest current research priorities should be shifted to a greater emphasis on survival rates and causes of mortality.

A longitudinal study of Steller sea lion natality rates in the Gulf of Alaska with comparisons to census data.

Steller sea lion (Eumetopias jubatus) numbers in the Western Distinct Population Segment are beginning to recover following the dramatic decline that began in the 1970s and ended around the turn of the century. Low female reproductive rates (natality) may have contributed to the decline and remain an issue of concern for this population. During the 2000s we found high natality among Steller sea lions in the Gulf of Alaska indicating a healthy population. This study extends these previous estimates over an additional three years and tests for interannual variations and long-term trends. We further examine the proportions of pups to adult females observed on the rookery and nearby haulouts during the birthing season to assess whether census data can be used to estimate natality. Open robust design multistate models were built and tested using Program MARK to estimate survival, resighting, and state transition probabilities in addition to other parameters dependent on whether or not a female gave birth in the previous year. Natality was estimated at 70% with some evidence of interannual variation but a long-term increasing or decreasing trend was not supported by the data. Bootstrap and regression comparisons of census data with natality estimates revealed no correlation between the two methods suggesting that census data are not an appropriate proxy for natality in this species. Longitudinal studies of individual animals are an appropriate method for estimating vital rates in species with variable detection over time such as the Steller sea lion. This work indicates that natality remains high in this region and is consistent with a population in recovery.

Drawbacks of complex models in frequentist and Bayesian approaches to natural-resource management.

Previous studies have shown that, for managing harvest of natural resources, overly complex models perform poorly. Decision-analytic approaches treat uncertainly differently from the maximum-likelihood approaches these studies employed. By simulation using a simple fisheries model, I show that decision-analytic approaches to managing harvest also can suffer from using overly complex models. Managers using simpler models can outperform managers using more complex models, even if the more complex models are correct and even if their use allows the incorporation of additional relevant information. Decision-analytic approaches outperformed maximum-likelihood approaches in my simulations, even when Bayesian priors were uninformative.

Effects of health information in youth on adult physical activity: 20-year study results from the Amsterdam growth and health longitudinal study.

In the Amsterdam Growth and Health Longitudinal Study (AGAHLS), a group of apparently healthy males and females (n = 200) were interviewed about their physical activities on eight separate occasions over a period of 20 years between 13 and 33 years of age (multi-measured group: MM). Information about their health was given based on their personally measured lifestyle (activity, diet, smoking) and biological risk characteristics for chronic diseases (medical check-ups). A comparable group of boys and girls (n = 200) was only measured on two occasions (bi-measured group: BM): at 13 and 33 years. Physical activity was estimated with a structured interview. Total physical activity and sports activity were estimated in three intensity levels (light, moderate, and heavy). It was hypothesized that the eight repeated medical check-ups with health information in the MM group would result in a healthier lifestyle with respect to the determinants and levels of habitual physical activity compared to the BM group. Contrary to the hypothesis, males and females in the BM group showed a significantly higher increase or a lower decrease in physical activities compared to the MM group. This negative effect on the physical activity pattern at 33 years in the MM group may have been caused by more underreporting of physical activities than in the BM group. In conclusion, there does not appear to be a significant effect of long-term (multi-measured) health information with medical check-ups during adolescence and young adulthood on level of physical activity in males and females at 33 years of age.

[Azithromycin combined with pyrimethamine in the treatment of neurotoxoplasmosis, in an AIDS patient]. / Azitromicina in associazione a pirimetamina nel trattamento della neurotoxoplasmosi, in un paziente con AIDS.

We report one case of successful treatment of cerebral toxoplasmosis in acquired immunodeficiency syndrome (AIDS) with azithromycin combined with pyrimethamine. Toxoplasmic encephalitis had been diagnosed on the basis of multiple lesions exhibiting ring like contrast enhancement on double contrast Computed Tomographic (CT) scan of the brain. Thereby our patient had been treated with pyrimethamine 25 mg/die, after an attack dose of 100 mg in the first day, and clindamycin 2400 mg/die, because of sulfa-drug allergy, but clindamycin had to be discontinued because of rash development. At this point azithromycin, at a dose of 1000 mg/die for 21 days and 1500 mg a week for the following 50 days of follow-up, was added to pyrimethamine. Follow-up CT scan after 20 days of treatment (10 with clindamycin+pyrimethamine and 10 with azithromycin+pyrimethamine) revealed partial resolution of the brain lesions and subsequently (after 50 and 80 days of treatment) complete resolution.

Use of furazolidone for the treatment of microsporidiosis due to Enterocytozoon bieneusi in patients with AIDS.

The efficacy of furazolidone for treatment of intestinal microsporidiosis due to Enterocytozoon bieneusi was studied in three patients with AIDS. All patients had chronic diarrhoea and weight loss. Mean CD4 cell count was 34.6/mm3. A course of furazolidone (100 mg orally four times a day) was given for 20 days. The drug was well tolerated and neither side effects nor alterations in the laboratory parameters were noted. Diarrhoea ceased within a mean of 12 days of starting treatment and clearance of microsporidian shedding in stool was observed. In one of the patients, however, symptomatic microsporidiosis recurred. Therefore furazolidone seems to have a transient but significant effect on intestinal infection due to Enterocytozoon bieneusi.

Combined antineoplastic and antiretroviral therapy for patients with Hodgkin's disease and human immunodeficiency virus infection. A prospective study of 17 patients. The Italian Cooperative Group on AIDS and Tumors (GICAT).

BACKGROUND: The optimal therapeutic approach for patients with Hodgkin's disease (HD) and human immunodeficiency virus (HIV) infection is unknown. In an attempt to improve the results obtained with standard chemotherapy and to decrease the occurrence of opportunistic infections (OI) during chemotherapy and follow-up observed in a previous experience, the authors designed a prospective combined antineoplastic and antiretroviral approach. METHODS: Between March 1989 and March 1992, 17 consecutive previously untreated patients (median age, 30 years) with HD and HIV infection were enrolled. They had Stage III and IV or Stage I and II disease with adverse prognostic factors. The median CD4+ cell count was 184/microliters. Patients were stratified in two groups and treated accordingly. Group A was made up of patients with an Eastern Cooperative Oncology Group (ECOG) performance status (PS) of less than 3 and without OI. These patients received epirubicin 70 mg/m2 intravenously on day 1, bleomycin 10 mg/m2 IV on day 1, and vinblastine 6 mg/m2 IV on day 1 (regimen EBV). Group B was made up of patients with PS of 3 or greater or previous OI who had received a 50% reduced dose of epirubicin and vinblastine and a full dose of bleomycin. Courses were repeated every 21 days for six cycles. Zidovudine was given at the dose of 500 mg/day from the beginning of chemotherapy in Group B and after the third cycle in Group A. RESULTS: Overall, 14 of 17 (82%) patients had an objective response and 9 of 17 (53%) achieved a complete remission (CR) of disease for a median duration of 20 months. Toxicity was moderate with Grade 3-4 leukopenia in eight patients and Grade 3 thrombocytopenia in one patient. Thirteen of 17 patients received zidovudine as planned with a median duration of 9 months. Only one patient had OI during or after chemotherapy (median follow-up, 11 months). No worsening of HIV markers during the combined therapy was seen, with the median CD4+ cell count before and after therapy being 184/microliters and 203/microliters, respectively. The median survival time was 11 months, with an actuarial survival rate of 48% at 36 months. The median survival time for the nine patients with CR has not been reached at the time of this analysis. CONCLUSIONS: These results revealed the feasibility and the activity of the combination of EBV regimen and zidovudine. Objective response rate seems similar to those previously observed in patients receiving standard chemotherapy, but only one patient had OI, and this compares favorably with the 16 OI observed in 28 patients treated with standard chemotherapy (6% versus 57%) in the authors' previous experience. Thus, it seems that the addition of antiretroviral therapy to the EBV regimen decreased the occurrence of OI during chemotherapy or follow-up.

White lichenoid lesions of the buccal mucosa in patients with HIV infection.

We report on eight patients who developed white lichenoid lesions of the buccal mucosa during the course of human immunodeficiency virus infection. In five patients the lesions appeared after the administration of zidovudine, in two after the intake of both zidovudine and ketoconazole, and in one after ketoconazole. In the majority of cases, lesions presented as bilateral reticular keratosis or atrophic changes of the buccal mucosa. Three patients manifested lichenoid atrophic changes of the dorsum of the tongue. The histopathologic features were hyperkeratosis, epithelial atrophy, basal cell liquefaction, and the presence in the lamina propria of either a patchy or diffuse lymphocytic infiltrate. All specimens tested negative for Epstein-Barr virus and human papillomavirus. Our study suggests that lichenoid lesions of the buccal mucosa, similar to what has been described as lichenoid drug reactions or idiopathic lichen planus, can be observed during human immunodeficiency virus infection and that administration of zidovudine and ketoconazole should be considered as a possible cause.

[Isosporiasis and sarcocystosis. The current findings]. / Isosporiasi e sarcocistosi. Acquisizioni attuali.

A review on infections by Isospora belli and Sarcocystis spp. both in healthy and in AIDS patients is done on the basis of literature and personal data. In this view a special focus is made on isospora belli infection in AIDS because of its high recurrence after successful attack therapy. Consequently the most recent protocols for maintenance and attack therapy in these patients are reported. At the end, concerning ultrastructural pathology, the features of some Isospora belli developing stages are described by means of electron microscopy on duodenal biopsy specimens from a patient.

Hairy leukoplakia with involvement of the buccal mucosa.

Oral hairy leukoplakia occurs mainly on the tongue of human immunodeficiency virus (HIV)-infected persons. An HIV-infected patient with hairy leukoplakia involving the tongue and buccal mucosa was studied by light and electron microscopic methods, in situ hybridization, and polymerase chain reaction. Our findings indicate that hairy leukoplakia may involve the buccal mucosa and should be considered in the differential diagnosis of white oral lesions in HIV-positive patients. Epstein-Barr virus particles were found in the epithelial cells of both buccal and tongue mucosa.

[Proctocolitis caused by Schistosoma mansoni in AIDS. A clinical and immunohistochemical study of a case]. / Proctocolite da Schistosoma mansoni in AIDS. Studio clinico ed immunoistochimico di un caso.

An imported case of intestinal schistosomiasis in AIDS is analysed by the relationships between immune response, diagnostic methods, pathogenetic mechanisms. The inconclusiveness of negative results from both serology and stool parasitology is remarked whereas the efficacy of associated histological, histochemical and immunohistochemical methods is emphasized in order to get better data on aetiological diagnosis and on cell types and size of reactive granulomas. In the case studied, negative serology, absent fecal egg excretion and uneffective granulomatous response with scarcity of T and B lymphocytes have been documented by means of the above methods.

In vitro infection with HIV enables human CD4+ T cell clones to induce noncognate contact-dependent polyclonal B cell activation.

Eleven (nine CD4+ and two CD8+) protein purified derivative-specific and eight tetanus toxoid-specific T cell clones (TCC), established from the peripheral blood of healthy persons, were cocultured in vitro with irradiated mononuclear cells from patients infected by HIV in the presence of PHA and polybrene. Two weeks post-HIV exposure, all 17 CD4+, but neither of the two CD8+, TCC exhibited integration of HIV in their genoma, as detected by polymerase chain reaction analysis, and released HIV into their supernatants, as detected by measuring both reverse transcriptase activity and p24 Ag. When co-cultured with either autologous or allogeneic B cells, all CD4+ HIV-infected TCC induced the synthesis of extraordinarily high amounts of IgM, IgG, and IgA. In contrast, their noninfected counterparts could provide helper function for Ig synthesis by autologous B cells only in the presence of the specific Ag (or anti-CD3 antibody), and induced allogeneic B cells to synthesize Ig only upon stimulation with anti-CD3 antibody. The supernatants of HIV-infected TCC failed to stimulate Ig synthesis in B cells. More importantly, when HIV-infected clonal T blasts and B cells were cultured in different chambers separated by a millipore membrane, permeable to molecules but not to cells, Ig synthesis did not occur. The Ig synthesis induced by HIV-infected TCC was also markedly inhibited by the addition in culture of either anti-CD4 or anti-LFA-1 antibody. In contrast, HIV-infected TCC maintained their ability to provide helper function for Ig synthesis in the absence of any stimulus, even after fixation with p-formaldehyde. These data demonstrate that in vitro infection with HIV enables human T cells to stimulate Ig synthesis by B cells by an Ag-nonspecific, MHC-unrestricted, contact-dependent mechanism. This may explain, at least in part, the hypergammaglobulinemia and other phenomena related to polyclonal B cell activation frequently seen in HIV-infected persons.

Morphology and membrane antigens of nonlymphoid accessory cells in oral hairy leukoplakia.

We have investigated the features and distribution of accessory cells (ACs) and the relationship of these cells to each other and to lymphocytes in the epithelium and lamina propria of oral hairy leukoplakia (HL), with the objective of better defining the differentiation and mutual interactions of immune-response cells within HL as a preliminary step to understanding the onset and significance of this lesion during human immunodeficiency virus (HIV) infection. Twenty-four HIV-infected patients with HL, two asymptomatic HIV-positive subjects, and three HIV-negative subjects were studied by immunohistochemistry; five HIV-positive patients with HL and three asymptomatic HIV-positive subjects were studied by electron microscopy. In both the epithelium and the lamina propria of HL, we found cells with the immunohistochemical and ultrastructural features of variably differentiated ACs; differences were found between the epithelium and lamina propria. In the lamina propria, ACs were characterized by dendritic shape, multiple contacts with lymphocytes, expression of CD1a antigen, and ultrastructural features of fully differentiated ACs. Conversely, in the epithelium ACs showed bluntly dendritic shape, low expression of CD1a, absent expression of HLA-DR, constant expression of CD11c and CD14 antigens, only occasional contacts with lymphocytes, and ultrastructural features of variably, but always incompletely, differentiated cells of monocyte-dendritic lineage. Seventy-nanometer wide intracisternal particles, closely resembling A particles described in retroviral infections, were found in the intraepithelial ACs in two patients with HL. The defective differentiation of ACs in the epithelium of HL--possibly influenced by the perturbation of the epithelial microenvironment induced by Epstein-Barr virus, and following the direct HIV infection of these cells--and the exceptional finding of close contacts with lymphocytes suggest that the lesional epithelium of HL may constitute a pathway for the entry of foreign antigens which circumvent monitoring by ACs and can induce immune tolerance. The impairment of the local immune response in HL may contribute to the development of full blown, systemic immunodeficiency.

[Pseudo-Whipple disease caused by atypical mycobacteriosis in AIDS: a clinical and electron microscopic study of 2 cases]. / Pseudo-malattia di Whipple da mycobatteriosi atipica in AIDS: studio clinico ed elettromicroscopico di due casi.

The Authors focus on two cases, studied by electron and light microscopy, of Whipple-like disease caused by atypical mycobacteria in AIDS. Differential characteristics between the cases and classical Whipple's disease are analyzed with regard to the diagnostic and therapeutical peculiarities of Mycobacterium avium-intracellulare infection which accounts for over 80% of atypical mycobacterial infections in AIDS. In this regard the Authors stress the role of histological findings of pale blue striated histiocytes as a marker of Mycobacterium avium-intracellulare infection.