Yeasts associated with nests of the leaf-cutting ant Atta sexdens rubropilosa Forel, 1908.

A total of 137 yeasts associated with the leaf-cutting ant Atta sexdens rubropilosa Forel, 1908 were characterized, being selected 93 for analysis. Twenty four species belonging to seven genera (Candida, Cryptococcus, Rhodotorula, Sporobolomyces, Tremella, Trichosporon, Pichia) were isolated from the different analysed material. The genus Candida was widely distributed, with C. homilentoma, C. colliculosa-like, C. famata and C. colliculosa being the most prevalent. A few isolates did not fit the standard descriptions and probably some of them could be new biotypes or even new species. Three strains of black yeasts were also isolated, and four other were identified as being Candida spp. The effective number of yeast species was higher in newer sponge. The origin, distribution and relative importance of these microorganisms for the ants are discussed.

Canine visceral leishmaniasis: successful chemotherapy induces macrophage antileishmanial activity via the L-arginine nitric oxide pathway.

Following successful chemotherapy in canine visceral leishmaniasis, monocyte-derived macrophages can induce antileishmanial activity via a gamma interferon-dependent mechanism in the presence of autologous lymphocytes. The killing of leishmania correlated with the induction of the NO synthase pathway, because it correlated with the generation of nitrogen derivative production and was abrogated in the presence of NG-monomethyl-L-arginine, a competitive inhibitor of the NO synthase pathway. The level of L-citrulline in serum, which was produced after activation of the NO synthase pathway, was markedly enhanced in dogs receiving successful chemotherapy. Taken together, these data indicate that following successful chemotherapy of visceral leishmaniasis, leishmania parasites are killed by macrophages activated by gamma interferon-producing lymphocytes via an NO-dependent mechanism.

Toxicity of lignans to symbiotic fungus of leaf-cutting ants.

Lignans fromVirola sebifera Aubl.,Virola sp., andOtoba parvifolia (Mkfg.) A. Gentry (Myristicaceae) inhibited the in vitro growth of the fungus cultivated by leaf-cutting ants of the speciesAtta sexdens rubropilosa Forel (Hymenoptera: Formicidae). A comparison of activity among the lignans was obtained.

CD23 and IgE expression during the human immune response to cutaneous leishmaniasis: possible role in monocyte activation.

Leishmania brasiliensis causes cutaneous leishmaniasis (CL) in humans. During this infection, a variety of inflammatory mediators are produced by T cells and monocytes/macrophages. In the present study, we analysed serum IgE levels and their correlation with in situ expression of the low affinity receptor for IgE (Fc epsilon RII/CD23) in patients infected with L. brasiliensis before and following therapy. These analyses were compared to in situ expression of tumour necrosis factor-alpha (TNF alpha), interleukin 3 (IL3), interferon-gamma (IFN gamma) and IL4. Disease-free individuals from the same endemic area sensitized with L. brasiliensis antigens were also included in this work. Our data indicate that during infection, serum levels of IgE and TNF alpha increased and correlated with elevated in situ expression of CD23, IL4 and TNF alpha mRNA. This expression disappeared following successful treatment, but persisted in patients resistant to anti-leishmania therapy. Patients resistant to therapy differed from other cases by a dramatic decrease in their in vivo expression of IFN gamma protein. Analysis of CD23 function in purified human monocytes indicated that this antigen mediates IgE/anti-IgE-dependent TNF alpha production. These data suggest a possible in vivo role of CD23 in acute immune responses in human CL.

[Visual screening in children]. / Rastreio visual em crianças.

The Early Visual Screening (EVS) before verbal communication and, certainly, before one year old, is essential to prevent strabismus and/or amblyopia. We consider the PREFERENTIAL LOOKING (PL) for visual acuity determination and screening of the amblyopia and the PHOTOREFRACTION (VIDEO-REFRACTION: VPR-1) for refractive screening, adequated methods for Early Visual Screening. We suggest that these two technics are used as EVS methods, four times in childhood (newborn, 6-8 weeks, 6-8 months, 18-24 months) performed by an Ophthalmologist at a Pilot Health Center of the National Health Service. The classic methods of visual screening such as: child's reaction to the eye occlusion, pursuit movements, STYCAR balls and miniature toys, Cover test, Hirschberg test, red fundus reflex, anterior segment examination, each of these used according to the child's age, must be performed by an Ophthalmologist. We think they are a positive alternative until we are able to use the PREFERENTIAL LOOKING and VIDEO-REFRACTION in Early Visual Screening. In the kindergarten and primary school the ASTENOPIC complaints due to hipermetropia, minor astigmatism and convergent deficit as well as chronic inflammation of the anterior segment eyelids and anexus, can be related with poor school performance more than with strabismus or myopia.(ABSTRACT TRUNCATED AT 250 WORDS)

[Postural deficiency syndrome. Its importance in ophthalmology]. / Le syndrome de déficience posturale. Son intérêt en ophtalmologie.

The Postural Deficiency Syndrome (P.D.S.) is a clinical situation always accompanied by an alteration of the ocular and postural equilibrium and by a defect of proprioceptive and visual information. The P.D.S. patients may present an important ophthalmological symptomatology which the classical semiological methods are not able to identify. To study properly these patients it was indispensable to introduce new methods of ophthalmological exploration. Among these new methods, the A.A. point out specially the directional scotometry and the linear directional coordinometry, found out and introduced by them. All these methods have allowed to detect in P.D.S. patients, troubles of directional visual information and typical disturbances of the tonic convergence. As a result of their investigation, the A.A. also describe a new therapy to the P.D.S. This therapy may complement the effects of somatoanalysis and reprogramming, always essential in the treatment of this situation. This new therapy is based on the introduction of a special correction, by means of prismatic lenses of low power, prescribed according to the rules that the A.A. also disclosed. The prismatic correction, appearing to be extremely effective, is well accepted by the great majority of the patients. The investigation work performed by the A.A. gives a new dimension to ophthalmology in the field of diagnosis, prophylaxis, treatment and rehabilitation of different situations of disability and incapacity.

Renal cortical necrosis following Bothrops jararaca and B. jararacussu snake bite.

Out of 22 patients admitted to the Intensive Care Unit of the Hospital das Clínicas, Federal University of Minas Gerais, with acute renal failure following Bothrops snake bite, 7 had renal cortical necrosis. This complication was suspected when the oligoanuric phase ranged from 21 to 28 days or when the patient, in spite of having a polyuric phase, maintained elevated blood levels of urea and creatinine after the interruption of the dialysis program, and was confirmed by a kidney biopsy. Three patients died and in two of them renal cortical necrosis was found at necropsy. Four patients were discharged from the hospital and follow-up was possible in two of them who showed recovery of renal function. Vasospasm, direct nephrotoxicity of Bothrops venom and/or disseminated intravascular coagulation leading to vascular occlusion and renal ischemia are the proposed pathogenetic mechanisms to explain renal cortical necrosis following Bothrops snake bite.

Hypokalemic respiratory muscle paralysis following Strongyloides stercoralis hyperinfection: a case report.

Strongyloides stercoralis hyperinfection in a malnourished 6-year-old boy was characterized by severe diarrhea, dehydration and marked hypokalemia, followed by acute respiratory failure due to respiratory muscle paralysis, and cardiac arrest. He was resuscitated and maintained with positive pressure ventilation and intravenous infusion of potassium and gluco-saline solution. These measures produced recovery from the respiratory muscle paralysis. Stool examination revealed eggs and numerous larvae of S. stercoralis, and thiabendazole was initiated. He continued to have severe diarrhea and again developed marked hypokalemia with respiratory muscle paralysis, abdominal distention, and cardiac arrhythmias with cardiac arrest episodes. In spite of fluid and electrolyte replacement the patient died.

Afibrinogenemia following snake bite (Crotalus durissus terrificus).

Following the bite of Crotalus durissus terrificus, an 11-year-old boy developed afibrinogenemia and high output acute renal failure. His platelet count remained within normal limits. He was treated with epsilon aminocaproic acid and whole fresh blood transfusion, with full recovery from afibrinogenemia 40 hours after the beginning of these measures and 75 hours after the snake bite. No hemorrhagic disturbances were present. The acute renal failure was treated conservatively, and the patient recovered 12 days after the snake bite and discharged from hospital with no sequelae.