Reliability and validity of the Biodex system 3 pro isokinetic dynamometer velocity,torque and position measurements

This study quantitatively assessed the mechanical reliability and validity of position, torque and velocity measurements of the Biodex System 3 isokinetic dynamometer. Trial-to-trial and day-to-day reliability were assessed during three trials on two separate days. To assess instrument validity, measurement of each variable using the Biodex System 3 dynamometer was compared to a criterion measure of position, torque and velocity. Position was assessed at 5° increments across the available range of motion of the dynamometer. Torque measures were assessed isometrically by hanging six different calibrated weights from the lever arm. Velocity was assessed (30°/s to 500°/s) across a 70° arc of motion by manually accelerating the weighted lever arm. With the exception of a systematic decrease in velocity at speeds of 300°/s and higher, the Biodex System 3 performed with acceptable mechanical reliability and validity on all variables tested.DisclosureThe Biodex dynamometer used for this investigation was donated to the laboratory by Biodex Medical Systems. The authors have no commercial or proprietary interest in this device.     

Synthesis of melanin-like pigments by Sporothrix schenckii in vitro and during mammalian infection

Melanin has been implicated in the pathogenesis of several important human fungal pathogens. Existing data suggest that the conidia of the dimorphic fungal pathogen Sporothrix schenckii produce melanin or melanin-like compounds; in this study we aimed to confirm this suggestion and to demonstrate in vitro and in vivo production of melanin by yeast cells. S. schenckii grown on Mycosel agar produced visibly pigmented conidia, although yeast cells grown in brain heart infusion and minimal medium broth appeared to be nonpigmented macroscopically. However, treatment of both conidia and yeast cells with proteolytic enzymes, denaturant, and concentrated hot acid yielded dark particles similar in shape and size to the corresponding propagules, which were stable free radicals consistent with identification as melanins. Melanin particles extracted from S. schenckii yeast cells were used to produce a panel of murine monoclonal antibodies (MAbs) which labeled pigmented conidia, yeast cells, and the isolated particles. Tissue from hamster testicles infected with S. schenckii contained fungal cells that were labeled by melanin-binding MAbs, and digestion of infected hamster tissue yielded dark particles that were also reactive. Additionally, sera from humans with sporotrichosis contained antibodies that bound melanin particles. These findings indicate that S. schenckii conidia and yeast cells can produce melanin or melanin-like compounds in vitro and that yeast cells can synthesize pigment in vivo. Since melanin is an important virulence factor in other pathogenic fungi, this pigment may have a similar role in the pathogenesis of sporotrichosis.     

Loss-of-function mutations in caspase recruitment domain-containing protein 14 (CARD14) are associated with a severe variant of atopic dermatitis

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Mutations in raised Drosophila melanogaster affect experience-dependent aspects of sexual behavior in both sexes

Many aspects of the reproductive behavior of Drosophila melanogaster are modified dramatically by experience and age. Males' courtship of immature males and fertilized females decreases over time. Females' receptivity to copulation, and the behaviors that females perform and elicit, are affected by their age and sexual experience. We show that mutations in a raised stock affect all of these age- and experience-dependent aspects of male and female sexual behavior. Experience has no effect on raised males' courtship of immature males and has opposite effects on raised and wild-type males' courtship of fertilized females. In comparison to controls, raised females become sexually mature at an earlier age, and sexually mature raised virgin females copulate more quickly. Following mating, raised females elicit more courtship and remate faster and more frequently than control females.     

Use of HeLa cell guanine nucleotides by Chlamydia psittaci.

Exogenous guanine was found to be incorporated into the nucleic acids of Chlamydia psittaci when the parasite was grown in HeLa cells containing hypoxanthine guanine phosphoribosyltransferase (EC 2.4.2.8) activity but not when the parasite was grown in transferase-deficient HeLa cells. No evidence for a chlamydia-specific transferase activity was found in either transferase-containing or transferase-deficient infected HeLa cells. It is concluded that C. psittaci is incapable of metabolizing guanine, but that the parasite can use host-generated guanine nucleotides as precursors for nucleic acid synthesis.     

Vitamin A Levels and Immunity in Humans

In animal studies, vitamin A deficiency induces a shift from type 2 (humoral) to type 1 (cellular) cytokines; there are no similar data for humans. Control of human immunodeficiency virus (HIV) and Mycobacterium tuberculosis infections requires type 1 cytokine (cellular) immunity. These infections and vitamin A deficiency are highly prevalent in Africa. We therefore examined the interactions among serum vitamin A levels, immune parameters, HIV infection status, Mycobacterium bovis BCG vaccine scarring (as an indicator of a type 1 cytokine profile), and clinical findings for 70 hospitalized children in Malawi, Africa. Directly conjugated monoclonal antibodies and flow cytometry were used to assess cell-specific cytokine production by peripheral blood monocytes and lymphocyte subpopulations. The statistical techniques employed included nonparametric statistics and logistic regression analyses. Thirty percent of the participants had severe vitamin A deficiency (<10 μg/dl), 34% had moderate deficiency (10 to <20 μg/dl), and 36% had normal levels (≥20 μg/dl). Vitamin A levels were lower for HIV-positive than for HIV-negative children (median, 10 and 17 μg/dl, respectively). Vitamin A-deficient children (<20 μg/dl) were more likely than non-vitamin A-deficient children to have higher proportions of natural killer (NK) cells (median, 8.3 and 5.2%, respectively) and lower ratios of interleukin-10-producing monocytes to tumor necrosis factor alpha-producing monocytes after induction (median, 1.0 and 2.3, respectively). Vitamin A-deficient children were also more likely than non-vitamin A-deficient children to exhibit respiratory symptoms (47% versus 12%) and visible BCG vaccine scars (83% versus 48%), which are indicative of a type 1 response to vaccination. Vitamin A status did not vary with gender, age, incidence of malaria parasitemia, blood culture positivity, or rates of mortality (6% of vitamin A-deficient children died versus 20% of non-vitamin A-deficient children). Lower vitamin A levels were associated with a relative type 1 cytokine dominance and proportionately more NK cells, both of which may be somewhat beneficial to persons who are exposed to HIV, M. tuberculosis, or other type 1 pathogens.     

Detection of enterovirus 70 with monoclonal antibodies.

To improve the ability to identify enterovirus-70 (EV-70) from patients with acute hemorrhagic conjunctivitis, we developed four monoclonal antibodies (MAbs) to EV-70. We reacted the four MAbs against nine previously characterized strains of EV-70 and heterologous viruses by virus neutralization, indirect immunofluorescence, and enzyme-linked immunosorbent assay (ELISA). Two of the MAbs neutralized all nine strains of EV-70 and none of the other enterovirus types tested. Two of the MAbs gave a positive reaction with all nine strains by indirect immunofluorescence, and three reacted with all nine strains by ELISA. None of the MAbs gave a positive reaction with heterologous viruses, including those associated with eye disease, by indirect immunofluorescence or ELISA. The two neutralizing MAbs failed to give a positive reaction with some of the strains of EV-70 by indirect immunofluorescence and ELISA, yet they neutralized these viruses. By ELISA with a polyclonal serum as capture antibody and a mixture of MAbs as detector antibody, we were able to detect from 10(2.2) to 10(5.8) 50% tissue culture infective doses of virus and to type lyophilized isolates of EV-70 sent from Taiwan from which we could not recover infectious virus. By choosing the appropriate MAb, or mixture of MAbs, we could construct a test which had the type specificity and strain sensitivity needed to type isolates of EV-70.     

Boosting with poxviruses enhances Mycobacterium bovis BCG efficacy against tuberculosis in guinea pigs

Tuberculosis is rising in the developing world due to poor health care, human immunodeficiency virus type 1 infection, and the low protective efficacy of the Mycobacterium bovis BCG vaccine. A new vaccination strategy that could protect adults in the developing world from tuberculosis could have a huge impact on public health. We show that BCG boosted by poxviruses expressing antigen 85A induced unprecedented 100% protection of guinea pigs from high-dose aerosol challenge with Mycobacterium tuberculosis, suggesting a strategy for enhancing and prolonging the efficacy of BCG.     

Interaction of Blastomyces dermatitidis, Sporothrix schenckii, and Histoplasma capsulatum with Acanthamoeba castellanii

Several dimorphic fungi are important human pathogens, but the origin and maintenance of virulence in these organisms is enigmatic, since an interaction with a mammalian host is not a requisite for fungal survival. Recently, Cryptococcus neoformans was shown to interact with macrophages, slime molds, and amoebae in a similar manner, suggesting that fungal pathogenic strategies may arise from environmental interactions with phagocytic microorganisms. In this study, we examined the interactions of three dimorphic fungi with the soil amoeba Acanthameobae castellanii. Yeast forms of Blastomyces dermatitidis, Sporothrix schenckii, and Histoplasma capsulatum were each ingested by amoebae and macrophages, and phagocytosis of yeast cells resulted in amoeba death and fungal growth. H. capsulatum conidia were also cytotoxic to amoebae. For each fungal species, exposure of yeast cells to amoebae resulted in an increase in hyphal cells. Exposure of an avirulent laboratory strain of H. capsulatum to A. castellanii selected for, or induced, a phenotype of H. capsulatum that caused a persistent murine lung infection. These results are consistent with the view that soil amoebae may contribute to the selection and maintenance of certain traits in pathogenic dimorphic fungi that confer on these microbes the capacity for virulence in mammals.