Spatially correlated fluorescence/AFM of individual nanosized particles and biomolecules.

Individual fluorescent polystyrene nanospheres (<10-100-nm diameter) and individual fluorescently labeled DNA molecules were dispersed on mica and analyzed using time-resolved fluorescence spectroscopy and atomic force microscopy (AFM). Spatial correlation of the fluorescence and AFM measurements was accomplished by (1) positioning a single fluorescent particle into the near diffraction-limited confocal excitation region of the optical microscope, (2) recording the time-resolved fluorescence emission, and (3) measuring the intensity of the excitation laser light scattered from the apex of an AFM probe tip and the AFM topography as a function of the lateral position of the tip relative to the sample substrate. The latter measurements resulted in concurrent high-resolution (approximately 10-20 nm laterally) images of the laser excitation profile of the confocal microscope and the topography of the sample. Superposition of these optical and topographical images enabled unambiguous identification of the sample topography residing within the excitation region of the optical microscope, facilitating the identification and structural characterization of the nanoparticle(s) or biomolecule(s) responsible for the fluorescence signal observed in step 2. These measurements also provided the lateral position of the particles relative to the laser excitation profile and the surrounding topography with nanometer-scale precision and the relationship between the spectroscopic and structural properties of the particles. Extension of these methods to the study of other types of nanostructured materials is discussed.

Platelet activation in Alzheimer disease.

BACKGROUND: In light of recent reports of diminished platelet serotonin concentration and increased plasma serotonin levels in patients with Alzheimer disease (AD), we hypothesized that a state of heightened platelet activation might be present in AD. OBJECTIVE: To compare baseline activation of unstimulated platelets in patients with AD with that in control subjects. PATIENTS AND METHODS: Flow cytometry was used to measure platelet activation in 91 patients with probable AD and 40 age-matched control subjects. Groups were compared for percentage of circulating platelet aggregates, expression of CD62p, formation of leukocyte-platelet complexes, and presence of circulating platelet microparticles, controlling for effects of demographic, clinical, physiological, and logistical factors. RESULTS: Multiple analysis of covariance on ranked data revealed a 39.5% increase in percentage of platelet aggregates (P=.0001), a 59.3% increase in expression of CD62p (P=.001), and a 53.3% increase in leukocyte-platelet complexes (P=.0001) in the group with AD but no differences in the number of platelet microparticles, overall platelet count, plasma fibrinogen level, or plasma platelet factor 3. Activation was weakly correlated with sex, but was independent of age, severity of disease, duration of disease, depression, agitation, and family history of dementia. CONCLUSIONS: Platelets of patients with AD exhibit greater unstimulated activation than those of controls. Potential causes of such activation include possible stimulation of platelets by damaged cerebral endothelial cells or platelet activation induced by membrane abnormalities previously reported to be present in platelets of patients with AD. In light of recent evidence that platelets are the principal source of both amyloid precursor protein and beta-amyloid peptide in human blood, it is possible that AD platelet activation may reflect or even contribute to the pathogenesis of the disease.

Platelet microparticles and calcium homeostasis in acute coronary ischemias.

UNLABELLED: Elevation of free cytoplasmic calcium is the common pathway of platelet activation, leading to shape change, shedding of platelet microparticles (PMP), aggregation, and secretion of internal granules, including expression of CD62p on the surface. Platelet activation is well documented in unstable angina (UA) and acute myocardial infarction (MI). We investigated the following markers of platelet activation in 55 patients undergoing coronary angiography for suspected CAD: free cytoplasmic calcium, [Ca2+]cyt, PMP, CD62p expression, and platelet/leukocyte (P/L) interaction. [Ca2+]cyt was measured by Fluo-3 and the other measurements were by flow cytometry. Patients were classified into three groups: unstable angina (UA, n = 11), recent myocardial infarction (MI, n = 11), and patient controls (CTL, n = 33). Blood was drawn before infusion of heparin through femoral lines at the time of catheterizaton for assays. ( RESULTS: (1) PMP values were significantly higher in both UA and MI than in CTL, P < 0.05. There was no difference between UA and MI. (2) P/L interaction was significantly elevated only in UA, P < 0.05. (3) CD62p expression on free platelets did not differ significantly between any of the three groups. (4) The resting [Ca2+]cyt, thrombin-induced Ca2+ influx, and release of Ca2+ from internal stores were all significantly higher in platelets from the combined patient group (UA + MI) than in the patient control group, P < 0.001 CONCLUSIONS: Results on calcium hemostasis and PMP were significantly different in patients with acute coronary syndromes than those with stable angina or no coronary ischemia; this may reflect underlying pathophysiology of acute coronary ischemia. P/L interaction was higher only in the UA group, suggesting a role of leukocytes in UA.

Danazol for paroxysmal nocturnal hemoglobinuria.

Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal stem-cell disorder in which blood cells lack complement inhibiting membrane proteins, and become susceptible to complement-mediated injury, leading to chronic intravascular hemolysis and pancytopenia. Glucocorticoids have been a mainstay of therapy. For patients refractory to glucocorticoids and requiring blood transfusions, an alternative therapy is needed. We studied danazol therapy in 5 patients refractory to other treatments. Four of the 5 benefited, showing rise in hematocrit and eventual cessation of transfusion requirements. Remissions lasted > or =2 years in 3 and 10 years in 1 patient. Danazol was well-tolerated without serious side effects. Danazol appears to be a good alternative treatment in PNH.

Activated platelet aggregates in thrombotic thromboctyopenic purpura: decrease with plasma infusions and normalization in remission.

Circulating activated platelet aggregates (aPA) were assayed by flow cytometry employing mAb alpha-CD62p in eight patients with thrombotic thrombocytopenic purpura (TTP). Elevation of aPA was observed in all patients in active stages of TTP; aPA normalized in remission. Plasma infusions with plasmapheresis decreased aPA in responding patients. The rise and fall of aPA preceded relapses and improvements, respectively. These changes were seen prior to the traditional indicators, LDH, haematocrit, and platelet count. Incubation of plasma from TTP patients with normal whole blood induced formation of aPA; this effect was significantly greater than that of plasmas from ITP patient controls (P < 0.01), suggesting the presence of an aPA-promoting factor in TTP plasma. Parallel experiments using a platelet aggregometer failed to detect effect of TTP plasma on normal blood. In summary, aPA appear to be a marker of disease activity, rising with relapse, falling with plasma therapy, and normalizing in remission. The flow cytometric assay of aPA is more sensitive than aggregometry in detecting the putative aPA-promoting factor in TTP.

Danazol relieves refractory pruritus associated with myeloproliferative disorders and other diseases.

Severe pruritus is frequently associated with myeloproliferative and other systemic illnesses, and often fails to respond to conventional measures. We used danazol (Danocrine), a synthetic attenuated androgen, in the treatment of severe pruritus refractory to conventional therapy. Eight patients had myeloproliferative disorders (MPD), seven had autoimmune disorders, and seven had skin diseases. Danazol at 400-800 mg/day was administered, and previous medications were tapered off. When itching was controlled with danazol alone, the dosage was reduced or discontinued, and resumed if itching recurred. Clinical responses were graded, and side effects were monitored. Overall, in 12 of 22 patients refractory to other measures, itching was controlled with danazol alone. In 10 patients itching returned when danazol was discontinued or dosage was continued for up to 5 years in responders. No serious side effects were observed. Our experience indicates that danazol is a good alternative for patients with severe pruritus associated with myeloproliferative and other systemic disorders.

Hemangioma vegetante intravascular / Vegetating intravascular haemangioma

Comunicamos un caso de Hemangioma Vegetante intravascular (H:V:I:)(Pseudoangiosarcoma de Masson)(P:A:M:) en el musculo de una mujer de 62 años sin lesion vascular prvia(forma primaria),pudiendo obtener la imagen clinica.Volvemos a resaltar el diagnostico diferencial con el angiosarcoma en su aspecto histologico.Preferimos los terminos de H:V:I: o P:A:M: y coincidimos en que la histogenesis corresponde a una forma peculiar de recanalizacion de un trombo (preceso reactivo y no neoplasico).

Hemangioma vegetante intravascular / Vegetating intravascular haemangioma

Comunicamos un caso de Hemangioma Vegetante intravascular (H:V:I:)(Pseudoangiosarcoma de Masson)(P:A:M:) en el musculo de una mujer de 62 años sin lesion vascular prvia(forma primaria),pudiendo obtener la imagen clinica.Volvemos a resaltar el diagnostico diferencial con el angiosarcoma en su aspecto histologico.Preferimos los terminos de H:V:I: o P:A:M: y coincidimos en que la histogenesis corresponde a una forma peculiar de recanalizacion de un trombo (preceso reactivo y no neoplasico).AU

Compromiso oral en dos casos de lepra lepromatosa / Oral compromise in two cases of lepromatous leprosy

Se publican 4 casos de acrodermatitis continua de Hallopeau,algunos de ellos seguidos durante mas de 20 años.Consideramos que la imagen histopatologica(pustula espongiforme)no autoriza a incluirla dentro de la psoriasis ya que son mas los puntos que las separan que los unen. Ellos son: manifestaciones cutaneas dolorosas,antecedentes,compromiso casi exclusivo de la extremidad distal del pulgar dejando en brotes sucesivos atrofia cutanea y esclerosis de tejidos blandos,afectacion temprana de la uña que puede conducir a la perdida de la lamina ungueal,respeto por la region central de palmas y plantas,compromiso oseo hasta severa mutilacion. No presenta lesiones tipicas de psoriasis vulgar en otros sitios,ni antecedentes familiares de ella ni HLA,B13,B17 yBW37

Compromiso oral en dos casos de lepra lepromatosa / Oral compromise in two cases of lepromatous leprosy

Se publican 4 casos de acrodermatitis continua de Hallopeau,algunos de ellos seguidos durante mas de 20 años.Consideramos que la imagen histopatologica(pustula espongiforme)no autoriza a incluirla dentro de la psoriasis ya que son mas los puntos que las separan que los unen. Ellos son: manifestaciones cutaneas dolorosas,antecedentes,compromiso casi exclusivo de la extremidad distal del pulgar dejando en brotes sucesivos atrofia cutanea y esclerosis de tejidos blandos,afectacion temprana de la uña que puede conducir a la perdida de la lamina ungueal,respeto por la region central de palmas y plantas,compromiso oseo hasta severa mutilacion. No presenta lesiones tipicas de psoriasis vulgar en otros sitios,ni antecedentes familiares de ella ni HLA,B13,B17 yBW37

Prurigo biopsiante / Biopsy prurigo

Comunicamos 5 casos de PB,4 con un fondo depresivo-ansiedad y 1 que corresponde a los denominados DOC. Hacemos hincapie en lo frecuente de esta patologia y la dificultad que le ocasiona al dermatologo o al clinico general su manejo. No se debe enviar al especialista en salud mental estos casos hasat no efectuar una relacion medico-paciente adecuada y comenzar a medicarlos sin temor. El diagnostico es sencillo y las terapeuticas farmacologicas son de mucho menor riesgo que las que habitualmente usamos para otras enfermedades. Ejemplo:corticoides,citostaticos,antimicoticos sistemicos entre otros. Finalmente con el complemento del psioquiatra en un porcentaje de casos se aliviara el sufrimiento cronico que ocasiona el PB

Perniosis: Estudio clinico e histologico de 5 casos / Perniosis: Histological and Clinical study of 5 cases

Incluimos en este trabajo 5 casos de perniosis(2 superficiales,2 profundas,1 mixta)observados durante el invierno de 1990 en nuestro servicio. Clinicamente se presentaron como maculas o pequenias placas dolorosas de coloracion rojo-violacea localizada en miembros inferiores(4 casos) y cara (1 caso). La histologia revelo la tipica angeitis linfocitaria con edema de la pared vascular. Referimos otras variantes histologicas y consideramos sus principales diagnosticos diferenciales

Prurigo biopsiante / Biopsy prurigo

Comunicamos 5 casos de PB,4 con un fondo depresivo-ansiedad y 1 que corresponde a los denominados DOC. Hacemos hincapie en lo frecuente de esta patologia y la dificultad que le ocasiona al dermatologo o al clinico general su manejo. No se debe enviar al especialista en salud mental estos casos hasat no efectuar una relacion medico-paciente adecuada y comenzar a medicarlos sin temor. El diagnostico es sencillo y las terapeuticas farmacologicas son de mucho menor riesgo que las que habitualmente usamos para otras enfermedades. Ejemplo:corticoides,citostaticos,antimicoticos sistemicos entre otros. Finalmente con el complemento del psioquiatra en un porcentaje de casos se aliviara el sufrimiento cronico que ocasiona el PB

Perniosis: Estudio clinico e histologico de 5 casos / Perniosis: Histological and Clinical study of 5 cases

Incluimos en este trabajo 5 casos de perniosis(2 superficiales,2 profundas,1 mixta)observados durante el invierno de 1990 en nuestro servicio. Clinicamente se presentaron como maculas o pequenias placas dolorosas de coloracion rojo-violacea localizada en miembros inferiores(4 casos) y cara (1 caso). La histologia revelo la tipica angeitis linfocitaria con edema de la pared vascular. Referimos otras variantes histologicas y consideramos sus principales diagnosticos diferenciales