Critical behavior of nanoparticle-containing binary liquid mixtures.

Simultaneous measurements of small-angle neutron scattering and dynamic light scattering have been performed on a binary mixture of partially miscible liquids, 2,6-dimethylpyridine and water. At critical composition the temperature dependence of the correlation length of fluctuations in composition is strongly affected by the addition of nanoparticles of a triblock copolymer polyethylene oxide-polypropylene oxide-polyethylene oxide. A crossover between Ising-type critical behavior and mean-field critical behavior is observed when the correlation length is equal to the size of the nanoparticles.

Self-assembled polymeric chelate nanoparticles as potential theranostic agents.

Improvements in cancer diagnostics and therapy have recently attracted the interest of many different branches of science. This study presents one of the new possible approaches in the diagnostics and therapy of cancer by using polymeric chelates as carriers. Graft copolymers with a backbone containing 8-hydroxyquinoline-5-sulfonic acid chelating groups and poly(ethylene oxide) hydrophilic grafts are synthesized and characterized. The polymers assemble and form particles after the addition of a biometal cation, such as iron or copper. The obtained nanoparticles exhibit a hydrodynamic diameter of around 25 nm and a stability of at least several hours, which are counted as essential parameters for biomedical purposes. To prove their biodegradability, a model degradation with deferoxamine is performed and, together with high radiolabeling efficiency with copper-64, their possible use for nuclear medicine purposes is demonstrated.

Scintillation SE detector for variable pressure scanning electron microscopes.

We present results obtained with a new scintillation detector of secondary electrons for the variable pressure scanning electron microscope. A detector design is based on the positioning of a single crystal scintillator within a scintillator chamber separated from the specimen chamber by two apertures. This solution enables us to decrease the pressure to several Pa in the scintillator chamber while the pressure in the specimen chamber reaches values of about 1000 Pa (7.5 Torr). Due to decreased pressure, we can apply a potential of the order of several kV to the scintillator, which is necessary for the detection of secondary electrons. Simultaneously, the two apertures at appropriate potentials of the order of several hundreds of volts create an electrostatic lens that allows electrons to pass from the specimen chamber to the scintillator chamber. Results indicate a promising utilization of this detector for a wide range of specimen observations.

Performance assessment of the fecal leukocyte test for inpatients.

Traditionally, fecal leukocyte testing detects large bowel inflammation or disruption, conditions that allow leukocytes into the stool. However, test usefulness with inpatients is unclear. Two hundred five inpatients who had undergone one to three tests were identified, and their FLT results were compared to their gastrointestinal disease diagnoses at time of discharge. A specificity of 92% for detecting intact colonic mucosae in inpatients was found.

Application of a heated electrospray interface for on-line connection of the AAS detector with HPLC for detection of organotin and organolead compounds.

A heated electrospray interface that affords high sensitivity and long-term signal stability for AAS detection of metal-containing analytes in organic or organic-water solvents after HPLC separation is described. The vitreous body of the electrospray interface is externally heated above the boiling point of the solvent and quartz furnace AAS is used for detection. Interface working conditions were optimized with a full experimental design for the detection of tin- (tetramethyl-, tetraethyl-, tetrabutyl-, and tetrapentyltin, tributyltin chloride, dibutyltin dichloride, and butyltin trichloride) and lead- (tetraethyl- and tetraphenyllead) containing compounds in the column eluate. The heated electrospray interface enables use of a wide range of flow rates - from 50 to 1000 micro L min(-1). The measurement sensitivity and detection limit achieved were compared with those obtained by use of the thermospray interface and post-column conversion of the organotin compounds to gaseous hydrides. The detection limits for the low-molecular weight species of the homologous series (2.8+/-0.1 ng (140+/-5 ng mL(-1)) for tetramethyltin and 3.1+/-0.2 ng (155+/-10 ng mL(-1)) for tetraethyltin) were obtained approximately one order of magnitude lower than those obtained by use of the thermospray interface. With this HPLC-ES-QFAAS system the tributyltin content of BCR reference material 477, mussel tissue, was analyzed. This system was also applied to analysis of tetraethyllead in gasoline samples.

Chronic rhinocerebral mucormycosis.

Rhinocerebral mucormycosis is a well-described fulminant fungal infection that typically presents acutely in patients with diabetic ketoacidosis or immunosuppression. Chronic presentations of rhinocerebral mucormycosis have also been described. In the chronic infection, the disease course is indolent and slowly progressive, often occurring over weeks to months. The authors report 2 cases of chronic rhinocerebral mucormycosis (CRM) treated at their institution and review 16 other cases reported in the English-language literature. In these cases, the median time from symptom onset to diagnosis was 7 months. The most common presenting features of CRM are ophthalmologic and include ptosis, proptosis, visual loss, and ophthalmoplegia. CRM occurs predominantly in patients with diabetes and ketoacidosis. The incidence of internal carotid artery and cavernous sinus thrombosis is higher in CRM patients than in those with the acute disease, although the overall survival rate for CRM patients is 83%. CRM is clinically distinct from chronic Entomophthorales infection.

Cytomegalovirus keratitis in acquired immunodeficiency syndrome.

A man with acquired immunodeficiency syndrome developed a generalized rash and bilateral dendritic epithelial keratitis without retinitis. Cytologic examination of superficial corneal scrapings showed many megalosyncytial giant cells that were highly characteristic of cytomegalovirus (CMV) infection. Viral cultures yielded CMV from 2 separate specimens obtained by corneal epithelial debridement from both eyes. The slightly elevated, opaque, branching, nonulcerative epitheliopathy recurred after corneal scrapings and persisted despite oral and topical antiviral therapy. Stromal keratouveitis subsequently developed. This case report confirms that CMV can produce corneal involvement and suggests that CMV keratitis may be an emergent complication of acquired immunodeficiency syndrome.

Cutaneous lesions due to Pleurophoma (Phoma) complex.

We report a case of striking and disfiguring facial mycosis due to an organism belonging to the Pleurophoma complex of Coelomycetes. This condition was likely acquired through repeated contact with infected soil and exacerbated by prolonged applications of topical corticosteroid preparations. Antifungal drug susceptibility testing was used to direct a therapeutic choice in this unusual infection.

Dematiaceous fungi are an increasing cause of human disease.

The dematiaceous fungi appear to be an increasing cause of human disease. At The Methodist Hospital, in Houston, Texas, five cases of serious disease caused by these fungi occurred between 1987 and 1992. Cerebral abscesses with Xylohypha bantiana followed treatment for lymphoma. An infection of the lower extremity with Exophiala jeanselmei var. castellanii followed cardiac surgery. Peritoneal growth of Alternaria tenuissima was a complication of peritoneal dialysis. Cerebral abscesses with Dactylaria gallopava occurred in a liver transplantation patient. A traumatic ankle wound contaminated with dirt led to an infection with Phialophora repens. All patients except the last were immunocompromised at the time of the infection; diabetics and patients on steroids may be at particular risk.

Pulmonary and disseminated infection due to Mycobacterium kansasii: a decade of experience.

Fifty-five patients with Mycobacterium kansasii isolates (47 pulmonary and eight disseminated) were identified at a large Texas hospital from 1975 to 1985. The mean age of patients was 60 years, and there was a slight male predominance. Isolation of M. kansasii usually represented disease. The great majority of patients with pulmonary infection due to M. kansasii had underlying pulmonary diseases, and 70% had nonpulmonary predisposing factors. M. kansasii pulmonary disease clinically and radiographically resembled pulmonary tuberculosis. Disseminated M. kansasii infection occurred in severely immunocompromised patients, who frequently had pulmonary predispositions as well. Disseminated infection most of ten involved the lung, reticuloendothelial system, bone, joint, and skin and presented with signs and symptoms related to these organs. Despite only moderate in vitro susceptibility of M. kansasii to routine antituberculous drugs, most patients responded to rifampin-containing regimens. The prognosis of patients with M. kansasii disease was determined primarily by their underlying diseases.

Genital white piedra: epidemiology, microbiology, and therapy.

The epidemiology of genital white piedra was investigated in 166 young men with a variety of genital complaints. Trichosporon beigelii was isolated from sixty-six (40%) of the cultured scrotal hairs. Infection was more common among black patients--54% of those examined, compared to 16% of white patients and 30% of "others" (p less than 0.001). There was no relationship between infection and foreign travel. White piedra was also found in young women, but less frequently than in young men (14% vs 40%, respectively). Transmission rarely occurred from person to person. Occasionally multiple body sites were simultaneously infected. A relationship may exist between T. beigelii and Corynebacterium concurrently infecting genital hair shafts. Eradication of infection was extremely difficult, despite in vitro sensitivity to antifungal agents. Spontaneous remissions occurred, however, in some patients.