Aspergillus pancarditis following bone marrow transplantation for chronic myelogenous leukemia

A 34-year-old man with chronic myelogenous leukemia developed hemoptysis, pain in the left side of the chest, and a systolic heart murmur eight weeks following an allogeneic bone marrow transplant. His clinical status deteriorated, and he died ten weeks after transplantation. Autopsy revealed unsuspected disseminated aspergillosis, including the unusual finding of Aspergillus pancarditis and pericarditis. Cardiac aspergillosis is a uniformly lethal disease in immunocompromised persons and must be aggressively diagnosed following early symptoms.     

Effect of calcium antagonist drugs on calcium currents in mammalian skeletal muscle fibers

The calcium channel-inhibiting drugs diltiazem, verapamil and nitrendipine represent three general classes of organic calcium antagonists. In the present study, the effect of these drugs on calcium currents (ICa++) in rabbit sternomastoid muscle fibers was examined. ICa++ were recorded at room temperature using a vaseline gap voltage clamp. ICa++ measured had similar kinetics to those reported in rat skeletal muscle, were partially blocked by 0.5 mM CdCI2 and could be reduced by substitution of Mg++ for Ca++. Diltiazem reversibly blocked ICa++ in a concentration-dependent manner with the 50% inhibitory concentration (IC50) being 63 microM. Verapamil was slightly more potent with approximately 50% block of ICa++ occurring at 10 microM. In contrast, nitrendipine at concentrations from 1 to 10 microM had no blocking action on ICa++, even after 20 min of exposure. Thus, although Ca++ channels in mammalian skeletal muscle fibers are readily blocked by cadmium, diltiazem and verapamil, these channels appear to be insensitive to the dihydropyridine compound nitrendipine.     

Human microsporidial infections.

Microsporidia are obligate intracellular spore-forming protozoal parasites belonging to the phylum Microspora. Their host range is extensive, including most invertebrates and all classes of vertebrates. More than 100 microsporidial genera and almost 1,000 species have now been identified. Five genera (Enterocytozoon spp., Encephalitozoon spp., Septata spp., Pleistophora sp., and Nosema spp.) and unclassified microsporidia (referred to by the collective term Microsporidium) have been associated with human disease, which appears to manifest primarily in immunocompromised persons. The clinical manifestations of microsporidiosis are diverse and include intestinal, pulmonary, ocular, muscular, and renal disease. Among persons not infected with human immunodeficiency virus, ten cases of microsporidiosis have been documented. In human immunodeficiency virus-infected patients, on the other hand, over 400 cases of microsporidiosis have been identified, the majority attributed to Enterocytozoon bieneusi, an important cause of chronic diarrhea and wasting. Diagnosis of microsporidiosis currently depends on morphological demonstration of the organisms themselves. Initial detection of microsporidia by light microscopic examination of tissue sections and of more readily obtainable specimens such as stool, duodenal aspirates, urine, sputum, nasal discharge, bronchoalveolar lavage fluid, and conjunctival smears is now becoming routine practice. Definitive species identification is made by using the specific fluorescein-tagged antibody (immunofluorescence) technique or electron microscopy. Treatment options are limited, but symptomatic improvement of Enterocytozoon bieneusi infection may be achieved with the anthelmintic-antiprotozoal drug albendazole. Preliminary observations suggest that Septata intestinalis and Encephalitozoon infections may be cured with albendazole. Progress is being made with respect to in vitro propagation of microsporidia, which is crucial for developing antimicrosporidial drugs. Furthermore, molecular techniques are being developed for diagnostic purposes, taxonomic classification, and analysis of phylogenetic relationships of microsporidia.     

A high percentage yield of tyrosine hydroxylase-positive cells from rat E14 mesencephalic cell culture.

In the ventral mesencephalon of the E14 rat fetus, 90% of the dopaminergic, tyrosine hydroxylase positive (TH+) cells are localized in 1.0 mm3 of tissue. This same ventral mesencephalic region also contains 90% of the dopamine content of the E14 ventral brainstem (2.2 +/- 0.3 nmol/mg protein). When cells were prepared for culturing from this localized area, and plated at a density of 2.5 x 10(5) cells/cm2, 17-21% of the cells were TH+, at 4 and 12 h, and at 1, 5, 7 and 10 days after plating. The percentage of TH+ cells was also 17-21% when examined at 4 h, 12 h or 5 days after plating at densities ranging from 7.8 x 10(3) to 2.5 x 10(5) cells/cm2. However, cell survival at a density of less than 6.2 x 10(4) cells/cm2 was poor after 5 days in culture. Based on the degree of neurite elongation and complexity, cell maturation appeared to be complete at 5 days in culture (DIV5), and appeared to be maintained at this level up to DIV10. By DIV14, neurite retraction was evident, and the cells were more rounded. These signs may indicate the inception of senescence in the cultures. A benztropine-sensitive, concentration-dependent dopamine uptake mechanism was demonstrated in the cultures at DIV7, and DA could be released from preloaded cells using 50 mM K+. Five morphological subtypes of TH+ cells were identified in the cultures. This primary culture of the ventral mesencephalic, dopaminergic area, with a high percentage of TH+ cells, is suitable for use in acute biochemical and cellular studies, between DIV 5 and DIV10.     

Matrix Vesicles Promote Mineralization in a Gelatin Gel

Extracellular matrix vesicles (MVs) are associated with initial calcification in a variety of tissues, but the mechanisms by which they promote mineralization are not certain. In this study, MVs isolated from fourth passage rat growth plate chondrocyte cultures were included within a gelatin gel into which calcium and phosphate ions diffused from opposite ends. In this gel, apatite formation occurs by 3.5 days in the absence of mineralization promoters, allowing measurement of the ability of different factors to ``nucleate' apatite before this time or to assess the effects of molecules which modulate the rate and extent of mineral deposition. Mineral ion accumulation and crystal type are assayed at 5 days. In this study, MV protein content in the central band of a 10% gelatin gel was varied by including 100 μl of a Tris-buffered solution containing 0–300 μg/ml MV protein. There was a concentration-dependent increase in mineral accretion. Whereas 10 μg MV protein in the gel did not significantly promote apatite formation as compared with vesicle-free gels, 20 and 30 μg MV protein in the gel did promote apatite deposition. Inclusion of 10 mM β-glycerophosphate in the gels, along with MVs, did not significantly increase apatite formation despite the demonstrable alkaline phosphatase activity of the MVs. In contrast, MVs at all concentrations significantly increased apatite accumulation when proteoglycan aggregates or ATP, inhibitors of apatite formation and proliferation, were included in the gel. Slight increases in calcium, but not phosphate accumulation, were also noted when an ionophore was included with the MVs to facilitate Ca ion transport into the vesicles. FT-IR analysis of the mineral formed in the vesicle-containing gels revealed the presence of a bone-like apatite. These data suggest that MVs facilitate mineralization by providing enzymes that modify inhibitory factors in the extracellular matrix, as well as by providing a protected environment in which mineral ions can accumulate. Received: 28 January 1996 / Accepted: 9 August 1996