Aislamiento de levaduras del género Cryptococcus de excretas de palomas / Isolation of yeast of the genus Cryptococcus in pigeonïs faeces

La criptococosis es una micosis oportunista causada por una levadura encapsulada, Cryptococcus neoformans. El microorganismo ha sido aislado en las excretas y nidos de palomas, ya que éstos son ricos en sustancias orgánicas, con humedad relativa que favorece el crecimiento de las levaduras. En nuestro medio se ha observado que los centros hospitalarios se encuentran frecuentemente "habitados" por palomas, constituyendo una probable fuente de infección para los pacientes hospitalizados, que pueden estar inmunosuprimidos, bien sea por la patología de base que presenten, la administración de drogas inmunosupresoras, antibioticoterapia u otros tratamientos. Si a estos pacientes inmunocomprometidos se le añade otro factor de riesgo, como puede ser la inhalación de esporas de hongos oportunistas, representaría un problema de salud pública

Incidencia y tipos de hongos (mohos y levaduras) y levaduras osmotolerantes en mieles venezolanas / Incidence and types of fungal (molds and yeast) and osmotolerant yeast in Venezuelan honeys

Este estudio tiene por objetivos conocer la cantidad de hongos (mohos y levaduras), y de levaduras osmotolerantes en mieles nacionales, y las repercusiones de ello sobre su estabilidad e inocuidad; así como probar la utilidad de estos recuentos como indicadores de la calidad sanitaria y la comercial. Se analizaron 62 muestras de mieles. Los recuentos de mohos y levaduras se hicieron según el método de la ICMSF (1978), y los de levaduras osmotolerantes, según el método de la APHA (1984), con incubación de 5 días. Las levaduras se identificaron por los métodos de fermentación y asimilación de Wickerham, y los mohos por morfología macro y microscópica. La detección de alteraciones se llevó a cabo después de almacenar las mieles entre 25-30 C, por 1 año. La investigación de Aflatoxinas se hizo por cromatografía de capa fina. Se encontró buena correlación entre mieles con bajos recuentos de hongos (82,3 por ciento ) con valores iguales ó inferiores a 100 ufc/g), humedad inferior a 20 por ciento , y menor incidencia de otros contaminantes. Entre las especies de mohos identificadas, son potencialmente toxigénicas las de los géneros Penicillium y Aspergillus (A flavus, A. niger, A. versicolor). La investigación de Aflatoxina en la miel con A. flavus resultó negativa. De las muestras alteradas, 70 por ciento tenían recuentos elevados de levaduras. Se concluye que los recuentos de mohos y levaduras son buenos indicadores de la calidad higiénica, y los de levaduras osmotolerantes lo son de la calidad comercial del producto , por tanto, se sugiere incluir en la Norma COVENIN 2191-84:a)Los recuentos de hongos, según el siguiente plan de muestreo: Mohos (ufc/g): n=5, c=2, m=10, M=100. Levaduras (ufc/g): n=5,c=2,m=10, M=100. b) Las determinaciones de levaduras osmotolerantes, interpretadas según lo establecido por Lochhead (1933) Por último , se hacen recomendaciones de higiene a objeto de minimizar las contaminaciones durante la producción y comercialización, a fín de obtener un producto inocuo que satisfaga las expectativas de los consumidores

Tiña inflamatoria en el cuero cabelludo a trichophyton tonsurans / Inflammatory tinea in the scalp of the left parietal region a trichophyton tonsurans

Se trata de un paciente pre-escolar, masculino, de 4 años de edad, quien es llevado a consulta de triaje del Hopital "J.M. de los Ríos", por presentar lesión tumoral en el cuero cabelludo de 2 semanas de evolución, de un tamaño aproximadamente de 2 cms. de diámetro, localizada en la region parietal izquierda, con abundates pústulas en su superficie. Se le practicaron estudios micrológicos en el Instituto Nacional de Higiene, encontrándoce el examen miroscópico del pelo parasitismo endotrix (cadenas de esporas dentro del cabello), en el cultivo se aisló Trichophytons tonsurans, además Estafilococo aureus del metrial de las pústulas. De acuerdo con el resultado del estudio micrológico, la lesion tumoral correspondía a un tinea capatis inflamatoria (Kerion Celsi), secundariamente infectado por agente bacteriano, la cual respondió satisfactoriamente al tratamiento antimicótico y antibioticoterapia por via oral. Se consideró importante la publicación de este caso por lo infrecuente de agente etiológico (Trichophytons tonurans) y además por la enseñaza que deja en cuanto a la orientación diagnóstica que debe hacerse en este tipo de lesiones tumorales en el cuero cabelludo, que muchas ocasiones son confundidas con abscesos bacterianos y/o miasis, se les practica se drenaje correspondiente originando entonces complicaciones futuras como alopecia cicatrizal permanente

Alteration of blood-brain-CSF barrier in experimental meningeal carcinomatosis. A morphologic and adriamycin-penetration study.

An experimental model of meningeal carcinomatosis has been produced by subarachnoid inoculation of B16 melanoma cells into C57BL mice. Injection of 10(3) viable cells was sufficient to cause 100% tumor incidence and death within a median survival time of 17 days. The tumor infiltrated diffusely the meninges of the brain and spinal cord and filled the ventricular system. Electron microscopic study of the leptomeningeal tumor revealed newly formed microvessels with fenestrated endothelium. The integrity of the blood-brain barrier was studied by the extravasation of the Evans blue and the Horseradish peroxidase tracers. Barrier disruption became evident from the seventh day on, using Evans blue. Electron microscopy study showed peroxidase activity in the luminal and abluminal sides of the meningeal microvessels, and within the tight junctions. Similar findings were noted in cortical capillaries adjacent to the meningeal tumor. Brain concentrations of Adriamycin (ADR) following administration of an intravenous dose of either 10 mg/kg or 50 mg/kg were measured on days 0 to 14 after tumor inoculation. A significant increase in mean +/- SEM content of whole brain ADR was observed only with the 50 mg/kg dose in days 7 to 14 (0.69 +/- 0.02 micrograms/g wet tissue weight) as compared to tumor-free controls (0.43 +/- 0.01, p less than 0.05). Our study suggests that barrier alteration in meningeal carcinomatosis allows extravasation of tracer solutes. Still, in order to achieve a significant increase in a water soluble drug penetration through the disrupted barrier, a high-dose drug regimen is required.

Evidence that central nicotinic-acetylcholine receptors are involved in the modulation of basal and stress-induced adrenocortical responses.

We investigated the involvement of central nervous system nicotinic-acetylcholine receptors in the secretory activity of the hypothalamic-hypophyseal-adrenal axis. Antiacetylcholine receptor antibodies derived from rabbits immunized with purified Torpedo-acetylcholine receptor or from myasthenia gravis patients were injected intracerebroventricularly into adult male rats for 5 consecutive days. Treatment with both preparations caused increased basal corticosterone concentrations, inhibition of the corticosterone response to ether stress, and neurological signs and motor dysfunctions. The adrenocortical response in experimental autoimmune myasthenia gravis Lewis rats with high circulating antiacetylcholine receptor antibodies was also tested. These rats exhibited a marked increase in basal corticosterone concentrations and a normal response to ether stress. The results showed that antinicotinic-acetylcholine receptor antibodies, either circulating or intraventricularly administered, can modulate both basal and stress-induced adrenocortical secretion.

Experimental allergic encephalomyelitis: passive transfer of resistance during lactation.

Pregnant rats challenged with encephalitogenic antigen in complete Freund's adjuvant (CFA) during pregnancy, transferred a resistance to induction of experimental allergic encephalomyelitis (EAE) in encephalitogenic challenged offspring. The resistance to induction of EAE was transferred during the whole lactation period, until weaning, and not during pregnancy. Through the milk, anti-myelin basic protein antibodies were transferred to the newborn animals. The degree of protection against EAE decayed with age and was not influenced by EAE occurrence in the mothers. In addition, the course of EAE in the rats was not affected by pregnancy. We believe that such transfer of resistance and antibodies may serve as a model for the study of milk-transmitted maternal immunocompetent factors, as well as a model for the mechanisms involved in the resistance of EAE.

Selective route of doxorubicin administration improves outcome in experimental malignant epidural cord compression.

Epidural spinal cord compression was produced in adult Fischer rats by injection of 10(6) viable cells of malignant fibrous histiocytoma anterior to the T-13 vertebral body. Using a tracer dye, it was demonstrated that a portion of the inoculum was always present in the anterior epidural space at the time of inoculation. Paraplegia and incontinence occurred consistently on Days 14 to 27 (median, 23 +/- 3.0). By sequential computed tomographic scans, the growth of the paravertebral tumor was documented and its volume was calculated. A single dose of cisplatin (i.p., 6 mg/kg) or doxorubicin (DXR, i.v. jugular, 6 mg/kg) was administered on Day 1. On Day 18, tumor volume was significantly reduced by DXR (P less than 0.001) and cisplatin (P less than 0.01), but paraplegia continued to occur as in the untreated rats. Comparison of treatment outcome with DXR administered via the jugular vs. the tail vein revealed that both were equally effective in retarding the growth of the paravertebral tumor, and both caused a similar transient leukopenia. However, only the tail DXR brought about a significant delay in the onset of paraplegia (P less than 0.004) and significantly increased the survival (P less than 0.001). It is suggested that the lack of efficacy of systemic chemotherapy for tumors located in the epidural space is probably related to inadequate drug exposure. The improved outcome with tail DXR infusion may be explained by the regional spinal venous perfusion, which allows an increase in the local drug concentration during its first passage through the epidural venous plexus.

Waterborne outbreak of Campylobacter enteritis.

A report is given on an outbreak of enteritis which occurred in July 1982 in a kibbutz near Jerusalem. About 150 of the 512 inhabitants were affected. Campylobacter jejuni was isolated from ten out of 42 stool samples examined toward the end of the outbreak. No other enteric pathogen was found. Strong circumstantial evidence indicated an association between the outbreak and the use of water from an unprotected reservoir, but no bacteriological confirmation was obtained.

Effect of intracerebroventricular injection of nicotinic acetylcholine receptor antibodies on ACTH, corticosterone and prolactin secretion in the male rat.

The aim of the present study was to investigate the involvement of CNS nicotinic receptors for acetylcholine in the secretory activity of the hypothalamo-hypophyseal-adrenal axis and prolactin (PRL). Adult male rats received a daily intraventricular injection of partially purified nicotinic acetylcholine receptor antibodies (anti-AChR) obtained from a female patient with myasthenia gravis, for 5 consecutive days. Control animals were treated similarly with immunoglobulins obtained from a healthy woman. Blood samples were withdrawn either under basal conditions or following ether stress. Treatment with anti-AChR increased basal ACTH and corticosterone (CS) levels (by approximately two-fold) but completely inhibited the responses of these hormones and PRL to ether stress. In control animals, normal basal and stress-induced responses of ACTH, CS and PRL were observed. This study demonstrated the importance for nicotinic acetylcholine receptors in the mediation of basal and stress-induced adrenocortical activity as well as for the mediation of PRL secretion in response to stress.

Alpha-fetoprotein suppresses experimental allergic encephalomyelitis.

Experimental allergic encephalomyelitis (EAE), induced in guinea pigs by immunization with myelin basic protein (MBP) or whole CNS homogenate was successfully treated, as well as partially prevented, by daily administration of fetal alpha-fetoprotein (alpha FP). alpha FP which is produced in high quantities during pregnancy can inhibit both the cell-mediated immune response to MBP and the binding of MBP antibody to the antigen in vitro. It has a non-specific immunosuppressive effect on both the cellular and humoral responses. It is suggested that the ability of alpha FP to suppress an experimental autoimmune disease, as presented in this model of EAE, indicates that clinical remissions of human autoimmune disease during pregnancy may be attributed to the effect of this natural substance.