Síndrome respiratorio agudo grave. El laboratorio de salud pública frente a una emergencia global / Severe acute respiratory syndrome: the public health laboratory in a global emergency

By the end of year 2002 there was an outbreak of atypical pneumonia in Southeast Asia which soon spread to other continents. This new severe acute respiratory syndrome (SARS) was produced by a novel coronavirus. Due to the severity of the situation and risk of introduction of this pathology in our country, the need to arrange specific laboratory diagnostic tests arose. Classic techniques, such as the electron microscopy and molecular biology test such as retrotranscription followed by the polymerase chain reaction (RT-PCR) were implemented. The araldit included cells infected with bovine coronavirus which allowed the viral particles to be visualized easily but it took more time in comparison with the negative staining of free particles from viral cultures. RT-PCR was able to detect RNA of isolated viruses from cases in Hong Kong and Germany.

A fines del año 2002 se inicia un brote de neumonía atípica en el Sudeste asiático el cual se extiende posteriormente a otros continentes. El nuevo síndrome respiratorio agudo grave (SARS) era producido por un coronavirus novedoso. Debido a la gravedad de la situación y al riesgo de introducción de esta patología en Argentina, se implementaron técnicas de diagnóstico clásicas como la microscopía electrónica, y moleculares como una reacción de retrotranscripción seguida de una reacción en cadena de la polimerasa (RT-PCR). La inclusiónen araldita de células infectadas con un coronavirus bovino permitió visualizar más fácilmente las partículas virales, pero requirió más tiempo en comparación con la coloración negativa de partículas libres de cultivos virales.La RT-PCR implementada fue capaz de detectar ARN de cepas de casos de Hong Kong y de Alemania.

Síndrome respiratorio agudo grave. El laboratorio de salud pública frente a una emergencia global / Severe acute respiratory syndrome: the public health laboratory in a global emergency

By the end of year 2002 there was an outbreak of atypical pneumonia in Southeast Asia which soon spread to other continents. This new severe acute respiratory syndrome (SARS) was produced by a novel coronavirus. Due to the severity of the situation and risk of introduction of this pathology in our country, the need to arrange specific laboratory diagnostic tests arose. Classic techniques, such as the electron microscopy and molecular biology test such as retrotranscription followed by the polymerase chain reaction (RT-PCR) were implemented. The araldit included cells infected with bovine coronavirus which allowed the viral particles to be visualized easily but it took more time in comparison with the negative staining of free particles from viral cultures. RT-PCR was able to detect RNA of isolated viruses from cases in Hong Kong and Germany. (AU)

A fines del año 2002 se inicia un brote de neumonía atípica en el Sudeste asiático el cual se extiende posteriormente a otros continentes. El nuevo síndrome respiratorio agudo grave (SARS) era producido por un coronavirus novedoso. Debido a la gravedad de la situación y al riesgo de introducción de esta patología en Argentina, se implementaron técnicas de diagnóstico clásicas como la microscopía electrónica, y moleculares como una reacción de retrotranscripción seguida de una reacción en cadena de la polimerasa (RT-PCR). La inclusiónen araldita de células infectadas con un coronavirus bovino permitió visualizar más fácilmente las partículas virales, pero requirió más tiempo en comparación con la coloración negativa de partículas libres de cultivos virales.La RT-PCR implementada fue capaz de detectar ARN de cepas de casos de Hong Kong y de Alemania. (AU)

Cyclospora cayatanensis en pacientes con SIDA y diarrea crónica / Cyclospora cayetanensis in patients with AIDS and chronic diarrhea

Cyclospora spp. is a protozoan parasite responsible for significant gastrointestinal disease in patients infected with the human immunodeficiency virus. We report the clinical features of two patients with chronic diarrhea and intestinal cyclosporosis caused by Cyclospora cayetanensis. The average value for CD4 count in these patients was lower than or equal to 100 cells/mm3. The oocysts were detected in smears from stool samples stained with modified acid-fast or safranin technique. Light microscopy revealed parasites in the enterocytes and these parasites were associated with villous atrophy. Cyclospora cayetanensis infection might be an important cause of diarrhea in patients with AIDS in Argentina.

Cyclospora cayatanensis en pacientes con SIDA y diarrea crónica / Cyclospora cayetanensis in patients with AIDS and chronic diarrhea

Cyclospora spp. is a protozoan parasite responsible for significant gastrointestinal disease in patients infected with the human immunodeficiency virus. We report the clinical features of two patients with chronic diarrhea and intestinal cyclosporosis caused by Cyclospora cayetanensis. The average value for CD4 count in these patients was lower than or equal to 100 cells/mm3. The oocysts were detected in smears from stool samples stained with modified acid-fast or safranin technique. Light microscopy revealed parasites in the enterocytes and these parasites were associated with villous atrophy. Cyclospora cayetanensis infection might be an important cause of diarrhea in patients with AIDS in Argentina. (AU)

Queratitis inflamatoria por acanthamoeba spp. análisis estructural por microscopía electrónica de transmisión / Infectious keratitis by acanthamoeba spp. amoeba structure. analysis using transmission electronics microscope

Se presenta el caso de una un paciente de 36 años, cuyo motivo de consulta fue visión borrosa y dolor ocular severo de 5 semanas de evolución, en ojo izquierdo. La paciente tenia como hábito el uso de lentes de contacto blandas con higiene inadecuada. Fue sometida a exámenes bacteriológicos y virológicos con resultados negativos. Para el presente estudio se extrajo material obtenido a través de una biopsia de córnea. Se realizó observación microscópica en fresco y con colorantes permanentes. Por medio de cultivos xénicos, se obtuvo trofozoitos y quistes de Acanthamoeba spp: Las colonias fueron observadas con microscopía óptica en fresco y con contraste de fases. Por MET (microscopía electrónica de transmisión) se analizó la ultraestructura de la ameba.

Isosporosis and unizoite tissue cysts in patients with acquired immunodeficiency syndrome.

Isospora belli, a coccidian parasite in humans, has been described as causing chronic diarrhea and acalculous cholecystitis in patients with the acquired immunodeficiency syndrome (AIDS). Diagnosis can be made at the tissue level in the epithelium of the small bowel and by fecal examination. Disseminated extraintestinal forms are uncommon. We studied 118 adult patients with AIDS and chronic diarrhea using stool analysis and endoscopy with duodenal biopsy specimen collection. These samples were processed by routine histology and transmission electron microscopy. Isosporosis was diagnosed in 8 cases. In 2 of them, unizoite tissue cysts were present in the lamina propria, with negative results in stool materials. The cysts were located within a large parasitophorous vacuole. There were no structural means of differentiating the species level of Isospora based on morphology using light or electron microscopy. We believe further work should be done to determine if unizoite tissue cysts are part of the cycle of I belli or of other species of Isospora that could be pathogenic in immunocompromised hosts.

Properties of two multisubstate Cl- channels from human syncytiotrophoblast reconstituted on planar lipid bilayers.

We describe the first successful reconstitution of placental ionic channels on planar lipid bilayers. An apical plasma membrane-enriched vesicle fraction from human syncytiotrophoblast at term was prepared by following isotonic agitation, differential centrifugation, and Mg2+-induced selective precipitation of nonapical membranes, and its purity was assessed by biochemical and morphological marker analysis. We have already reported that, unlike previous patch-clamp studies, nonselective cation channels were incorporated in most cases, a result consistent with the higher permeability for cations as compared with Cl- and with the low apical membrane potential difference at term revealed by fluorescent probe partition studies, and microelectrode techniques. In this paper, we report that Cl--selective channels were incorporated in 4% of successful reconstitutions (14 out of 353) and that their analysis revealed two types of activity. One of them was consistent with a voltage-dependent, 100-pS channel while the other was consistent with the lateral association of 47-pS conductive units, giving rise to multibarrelled, DIDS-sensitive channels of variable conductance (300 to 650 pS). The latter displayed a very complex behavior which included cooperative gating of conductive units, long-lived substates, voltage-dependent entry into an apparent inactivated state, and flickering activity. The role of the reported Cl- channels in transplacental ion transport and/or syncytium homeostasis remains to be determined.

Infección por Enterocytozoon bieneusi en un paciente con SIDA y diarrea crónica / Enerocytozoon bieneusi in a patient with AIDS and chronic diarrhea

Expone el caso clínico de un paciente de 37 años, de sexo masculino, con serología positiva para el VIH-1 y diarrea crónica, en el cual se identificó el Enterocytozoon bieneusi a través de las técnicas recomendadas para su diagnóstico. Enumera las especies identificadas de microsporidias asociadas a patologías en humanos, tanto intestinales como extraintestinales. El caso presentado constituiría la primera identificación fidedigna de una microsporidia en la Argentina por lo que se recomienda buscar estos patógenos a través de las técnicas de diagnóstico recomendadas en pacientes con SIDA y diarrea crónica o compromiso de la vía biliar en forma de colangitis

Infección por Enterocytozoon bieneusi en un paciente con SIDA y diarrea crónica / Enerocytozoon bieneusi in a patient with AIDS and chronic diarrhea

Expone el caso clínico de un paciente de 37 años, de sexo masculino, con serología positiva para el VIH-1 y diarrea crónica, en el cual se identificó el Enterocytozoon bieneusi a través de las técnicas recomendadas para su diagnóstico. Enumera las especies identificadas de microsporidias asociadas a patologías en humanos, tanto intestinales como extraintestinales. El caso presentado constituiría la primera identificación fidedigna de una microsporidia en la Argentina por lo que se recomienda buscar estos patógenos a través de las técnicas de diagnóstico recomendadas en pacientes con SIDA y diarrea crónica o compromiso de la vía biliar en forma de colangitis

Specific solute effects on Staphylococcus aureus cells subjected to reduced water activity.

The behaviour of Staphylococcus aureus cells subjected to lowered water activity (aw) by the addition of various solutes was examined by transmission electron microscopy. Solutes included sodium chloride, sucrose, propylene glycol, butylene glycol and various polyethylene glycols. Changes in other physical properties of the liquid growth medium brought about by the solutes were estimated theoretically. They did not correlate with the bacterial biological response. The inhibitory effects of sucrose and sodium chloride against S. aureus were primarily ascribed to their water activity-lowering abilities, showing no significant specific solute effects. However, the other solutes examined showed specific antibacterial activity against S. aureus which may be compatible with cell wall attack.

Submicroscopical changes in Klebsiella pneumoniae cells treated with concentrated sucrose and polyethylene glycol 400 solutions.

This study reports the extent and character of plasmolysis and other morphological changes as shown by electron microscopy in a strain of Klebsiella pneumoniae and with sucrose or polyethylene glycol 400 (PEG-400) as the plasmolysing agent at a water activity of 0.935. Both solutes produced severe plasmolysis in K. pneumoniae cells; PEG-400 also caused some cell wall collapse and finger like extrusions to emerge from the bacterial cell.

In vitro antibacterial activity of concentrated polyethylene glycol 400 solutions.

It was found that concentrated polyethylene glycol 400 (PEG 400) solutions have significant antibacterial activity against various pathogenic bacteria, including Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus. This effect might be attributed to two effects: lowering of water activity and, superimposed on this, the specific action of PEG-400 molecules on bacterial cells. Phase-contrast microscopic observations of cells placed in contact with PEG 400 revealed clumping and morphological changes of bacterial cells. The larger changes in appearance were evidenced by the species which were more rapidly killed by PEG 400. The results obtained suggested that concentrated PEG 400 solutions may have a potential value in medicine as a topical antibacterial agent. The feasibility of this application is the subject of present investigation.