Typing clinical and animal environment Aspergillus fumigatus gliotoxin producer strains isolated from Brazil by PCR-RFLP markers.

UNLABELLED: Aspergillus fumigatus, a well-known human and animal pathogen causing aspergillosis, has been historically identified by morphological and microscopic features. However, recent studies have shown that species identification on the basis of morphology alone is problematic. The aim of this work was to confirm the taxonomic state at specie level of a set of clinical (human and animal) and animal environment A. fumigatus strains identified by morphological criteria applying a PCR-RFLP assay by an in silico and in situ analysis with three restriction enzymes. The A. fumigatus gliotoxin-producing ability was also determined. Previous to the in situ PCR-RFLP analysis, an in silico assay with BccI, MspI and Sau3AI restriction enzymes was carried out. After that, these enzymes were used for in situ assay. All A. fumigatus strains isolated from corn silage, human aspergillosis and bovine mastitis and high per cent of the strains isolated from cereals, animal feedstuff and sorghum silage were able to produce high gliotoxin levels. Also, all these strains identified by morphological criteria as A. fumigatus, regardless of its isolation source, had band patterns according to A. fumigatus sensu stricto by PCR-RFLP markers. SIGNIFICANCE AND IMPACT OF THE STUDY: Aspergillus fumigatus is a well-known human and animal pathogen causing aspergillosis. In this study, clinical (human and animal) and animal environment strains were able to produce high gliotoxin levels and had band profiles according to A. fumigatus sensu stricto by PCR-RFLP markers. The results obtained here suggest that strains involved in human and animal aspergillosis could come from the animal environment in which A. fumigatus is frequently found. Its presence in animal environments could affect animal health and productivity; in addition, there are risks of contamination for rural workers during handling and storage of animal feedstuffs.

A mechanistic study of the photooxidation of A2E, a component of human retinal lipofuscin.

A major constituent of human retinal lipofuscin is A2E (2-[2,6-dimethyl-8-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E,7E-octatetraenyl]-1-(2-hydroxyethyl)-4-[4-methyl-6(2,6,6-trimethyl-1-cyclohexen-1-yl)-1E,3E,5E,7E-hexatrienyl]-pyridinium). Light transmitted by the lens is absorbed by A2E and the processes initiated by this absorption has been implicated in several maculopothies. The purpose of this study was to evaluate the dominant photochemical mechanisms involved in these reactions, whether through free radical or singlet oxygen intermediacy. The photodestruction of A2E occurs faster in water vs. chloroform and hydrogenated vs. perdeuterated methanol. Both results suggest a free radical mechanism. Product distributions indicate sequential oxygen addition rather than the addition of two oxygen atoms which would be expected if singlet oxygen was an intermediate. Finally, EPR trapping studies lead to the detection of superoxide as the primary intermediate in the photochemical reactions. It is concluded that if singlet oxygen is involved in these photochemical processes it is of minor importance.

Effect of viewed color on hand-grip strength.

Published reports on the effects of viewed color on physical strength are compromised by failure to specify each of the three dimensions of the color stimuli used. The present study investigated the relationship between color and grip strength by independently measuring the effects of the three dimensions of color. 80 students with normal color vision were tested for hand-grip strength while viewing color-stimuli sets which differed only in hue, saturation, or lightness. A two-way analysis of variance with two repeated measures showed no significant difference in hand-grip strength with changes in any dimension of color. Formal equivalence testing indicated that these results were not due to low statistical power but rather to an actual similarity in grip strength across different viewing conditions. The findings give clear support to those studies that have found no relationship between viewed color and strength.

Electroejaculation versus vibratory stimulation in spinal cord injured men: sperm quality and patient preference.

PURPOSE: We compared semen quality and patient preference between penile vibratory stimulation and electroejaculation in spinal cord injured men. MATERIALS AND METHODS: We treated 11 spinal cord injured men with penile vibratory stimulation and electroejaculation in random order. End points examined were semen analysis, sperm functional assessment, and patient pain scores (1 to 10) and preferred procedure. Differences between the procedures were determined with the paired Student t test. RESULTS: There was no difference in antegrade sperm count but penile vibratory stimulation specimens had greater motility (26.0 versus 10.7%), viability (25.2 versus 9.7%) and motile sperm count (185.0 x 10(6) versus 97.0 x 10(6)). The retrograde sperm count was greater (but not significant) in electroejaculation patients. The total (antegrade plus retrograde) and motile sperm counts were not different. There was no difference in immunobead test (all negative), cervical mucus penetration or sperm penetration assay, although the percent hamster egg penetration approached significance (53.7% for penile vibratory stimulation versus 22.1% for electroejaculation, p = 0.06). There was no difference in the peak blood pressures and no complications were noted. Pain scores were significantly greater for electroejaculation compared to penile vibratory stimulation (5.2 versus 1.7, respectively). All patients preferred penile vibratory stimulation. CONCLUSIONS: There was a slight advantage in sperm quality and a high patient preference in favor of penile vibratory stimulation. Penile vibratory stimulation should be attempted first to induce ejaculation in spinal cord injured men, with electroejaculation reserved for failures.

Functional characteristics of sperm obtained by electroejaculation.

Sperm obtained by electroejaculation in 32 anejaculatory men were examined for functional characteristics. Raw specimens showed high sperm counts but motility averaged only 11%. Average viability was 10% for antegrade and 5% for retrograde fractions. Bovine cervical mucus penetration was normal (30 mm. or more in 30 minutes) in only 24% of the electroejaculation samples but it was normal in all of the donor samples tested. Processed sperm motility averaged 30% with 71% forward progression. At 20 hours patient samples retained 46% of the original motility, while donor controls retained 81%. In the hamster egg penetration assay patient sperm penetrated 14% of the oocytes while donor sperm penetrated 40%. Therefore, we identified 4 characteristics of sperm obtained by electroejaculation: 1) low viability, 2) poor survival after overnight incubation, 3) moderately impaired cervical mucus penetration and 4) moderately poor fertilizing capability as measured by the hamster egg penetration assay. Poor sperm survival and impaired function may explain the low pregnancy rates from insemination with electroejaculated sperm.

Unfractionated spleen cells but not natural killer (NK) cells from RFM donors prevent the progression of host-versus-graft disease in murine RFM/(T6 x RFM)F1 chimeras.

Host-versus-graft (HVG) syndrome is the fatal allogenic disease which develops in susceptible strains of inbred mice following their perinatal inoculation with related F1 hybrid spleen cells. Deaths are caused by pathogenic immune complexes. It is thought that the antibody components of these complexes are produced by F1 donor B cells stimulated by the allogenic HVG reaction. To complement previous work that showed that lethal disease could be prevented if the HVG response was suppressed, the present studies tested whether or not it could also be prevented by augmenting HVG reactivity with the adoptive transfer of spleen cells syngenic with the host. The data show that unfractionated RFM spleen cells given on Days 13-14 prevented lethal disease in 86% of RFM/(T6 x RFM)F1 chimeras. Successful therapy was associated with the suppression of formation of nephropathic-immune complexes, and with the rejection of F1 donor cells or their gradual replacement by host cells. RFM spleen cells enriched for NK activity by a new improved method not only failed to prevent HVG disease but appeared to exacerbate it. This was also true of spleen cells that had been activated in vitro for 3 days with IL-2, a procedure that greatly enhanced their cytolytic activity against YAC-1 targets. It is suggested that therapy with NK cells failed, even after IL-2 activation, because they had no effect on proliferating and antibody-forming F1 donor cells that had engrafted in large numbers in the lymph nodes of the RFM hosts.

Apparent difference in the roles of spleen and lymph nodes in the pathogenesis of host-versus-graft disease in murine parent/F1 chimeras.

Host-versus-graft (HVG) disease is the often fatal immunodeficiency syndrome that can be induced in susceptible strains of mice by the perinatal inoculation of semiallogenic spleen cells. To determine the distribution and engraftment of the donor cells in the spleens and lymph nodes of RFM hosts, sequential tests were done for the presence of (T6 X RFM)F1 cells marked by their ability to form donor-specific antibodies to horseradish peroxidase (HRP) and by the T6 chromosome. Quantitation of cells with intracytoplasmic antibody that bound HRP (HRPBC) and of metaphases with the T6 marker showed that greater than 90% of donor cells were located in the hyperplastic lymph nodes. The pattern of sequential changes in numbers of HRPBC corresponded with the rise and fall in titers of antibodies to HRP. The marked differences in localization of donor cells suggested that host nodes and spleens played different roles. The lymph nodes became the main sources of donor antibodies and the principal repositories of (T6 X RFM)F1 cells capable of replication. The spleen evidently served as a major site of host resistance to engraftment. This was attributed to the ability of host cells there to inhibit selectively the proliferation of the semiallogenic donor cells. It is also proposed that counts of HRPBC measured the vigor of the HVG reaction in host spleen and lymph nodes, because the appearance of virtually all these antibody-forming cells was the result of the maturational effect of the allogenic reaction on F1 donor B memory cells.