Lot-to-lot variability of antibiotic medium 3 used for testing susceptibility of Candida isolates to amphotericin B.

We have previously shown that use of antibiotic medium 3 in the microdilution variant of the M27-T test method permits detection of amphotericin B-resistant Candida isolates. As this medium is not standardized and our initial work used only a single lot of antibiotic medium 3, we studied the lot-to-lot variability of three commercial lots of antibiotic medium 3 obtained from two sources. The MICs obtained with the new lots were lower than those of with the original lot, but the new lots still consistently separated putatively resistant and putatively susceptible isolates and this permits proposal of possible breakpoints for this assay system.     

Activity of liposomal nystatin against disseminated Aspergillus fumigatus infection in neutropenic mice.

The purpose of this study was to examine the activity of liposomal nystatin against a disseminated Aspergillus fumigatus infection in neutropenic mice. Mice were made neutropenic with 5-fluorouracil and were administered the antifungal drug intravenously for 5 consecutive days beginning 24 h following infection. Liposomal nystatin, at doses as low as 2 mg/kg of body weight/day, protected neutropenic mice against Aspergillus-induced death in a statistically significant manner at the 50-day time point compared to either the no-treatment, the saline, or the empty-liposome group. This protection was approximately the same as that for free nystatin, a positive control. Histopathological results showed that liposomal nystatin cleared the lungs, spleen, pancreas, kidney, and liver of Aspergillus and that there was no organ damage at the day 5 time point, which was after only three doses of liposomal nystatin. Based on these results in mice, it is probable that liposomal nystatin will be effective against Aspergillus infection in humans.     

In Vitro Synergy of Caspofungin and Amphotericin B against Aspergillus and Fusarium spp.

We investigated the in vitro interaction of caspofungin and amphotericin B for clinical isolates of Aspergillus and FUSARIUM: Synergy tests were performed using the checkerboard method and following the NCCLS M38-P guidelines in Antibiotic Medium 3 broth supplemented to 2% glucose. Antagonism was not observed for any of the isolates tested. Caspofungin and amphotericin B were synergistic or synergistic to additive for at least half of the isolates.     

Blind-ending tubules and branching patterns of the rat ductuli efferentes

The ductuli efferentes of Sprague-Dawley rats were studied by microdissection and microscopic evaluation to document the presence of blindending tubules (ductuli aberrantes) and to describe morphological and ultrastructural differences between normally open ductules and blind-ending tubules. The branching patterns of the ductuli efferentes varied considerably between animals. A majority of the animals studied had either six or seven ductuli connected to the rete testis, with some animals having as few as four or as many as eight. Pairs of ductules began merging in the conus vasculosa, ultimately forming a single terminal duct within the capsule of the initial segment epididymidis. In a majority of animals, the junctions were unequally matched and located at various positions within the conus. Blind-ending tubules, found in 60% of the animals, were surrounded by thick connective tissue, and had a smaller diameter (78.7 ± 1.4 μm) than normal ductules in the conus vasculosa (119.5 ± 2.1 μm) or the terminus (102.2 ± 1.5 μm). The lumina of blind-ending tubules were contracted and did not contain sperm. Nonciliated cells in the epithelium of blind-ending tubules contained fewer PAS-positive granules and electron-dense bodies (lysosomes) than nonciliated cells in normal ductules. Consideration of these characteristics will prevent blind-ending tubules from being mistaken for pathological changes in efferent ductules.     

Comparison of the action of the stereoisomers of the psychostimulant 4-methylaminorex (4-MAX) on midbrain dopamine cells in the rat: An extracellular single unit study

In this study, we examined and characterized the action of the stereoisomers of 2-amino-4-methyl-Δ²-5-phenyl-oxazoline (4-methylaminorex, 4-MAX) on spontaneously active dopamine (DA) neurons in the substantia nigra pars compacta (SNC or A9) and ventral tegmental area (VTA or A10) in anesthetized male rats. This was accomplished using the technique of extracellular single unit recording. The intravenous (i.v.) administration of the stereoisomers of 4-MAX (0.1?6.4 mg/kg) produced a dosedependent suppression of the basal firing rate of A10 DA cells with the following rank order of potency: trans 4S,5S > cis 4R,5S ≈? cis 4S,5R ? trans 4S,5S 4-MAX. The rank order of potency of the isomers of 4-MAX to suppress the firing of A9 DA cells was trans 4S,5S = cis 4R,5S = cis 4S,5R ? trans 4R,5R. The trans 4S,5S isomer was 5-fold more potent in suppressing DA cell firing in the A10 compared to the A9 area. The suppressant action of the isomers on A9 and A10 DA cells was reversed by the i.v. administration of haloperidol and the D₂/D₃ receptor antagonists (?)-sulpiride and (?)-eticlopride but not by the D₁ receptor antagonists SCH 23390 and SCH 39166. In addition, the suppressant action of the trans 4S,5S isomer on A10 DA cells was not antagonized or reversed by the i.v. administration of the receptor antagonists granisetron (5-HT₃), ritanserin (5-HT_{2A, C}), idazoxan (α₂), phentolamine (peripheral α₁), (±)-pindolol (5-HT_{1A, B}β) or prazosin (α1). The pretreatment of animals with either α-methyl-p-tyrosine (AMPT) or reserpine, but not p-chlorophenylalanine (PCPA), (±)-fluoxetine or tomoxetine, significantly attenuated the suppression of A10 DA cell firing produced by trans 4S,5S 4-MAX. Overall, our results suggest that the suppressant action of 4-MAX on midbrain DA cell firing may be mediated by the release of DA, which subsequently interacts with D₂/D₃ receptors. © 1995 Wiley-Liss, Inc.     

Wedge and subselective pulmonary angiography in pulmonary hypertension secondary to venous obstruction

Pulmonary wedge or subselective angiography provided key diagnostic information in two cases of pulmonary hypertension secondary to pulmonary venous obstruction. Whereas conventional pulmonary angiograms and ventilation-perfusion lung scans were interpreted as showing embolism, plain radiographs demonstrated Kerley B lines, suggesting venous obstruction. Subselective or wedge angiography of nonopacified arteries verified their anatomical patency and also revealed venous stenoses, collaterals, and atrophy indicative of obstruction.     

Neurofibromas: location by scanning with Tc-99m DTPA. Work in progress

The accumulation of technetium-99m diethylenetriamine pentaacetic acid (Tc-99m DTPA) in benign soft-tissue neurofibromatosis tumors is reported. In a series of 16 patients with clinical stigmata of neurofibromatosis, 28 sites of abnormal soft-tissue localization of the isotope observed scintigraphically were documented to be sites of soft-tissue tumor by clinical and/or radiographic (predominantly computed tomographic) correlations. The smallest lesion detected was a 1.5-cm subcutaneous neurofibroma. Normal physiologic nonrenal distribution of the Tc-99m DTPA was established by scintigraphic imaging of a control population.     

Parent behavioral training to modify child noncompliance: Effects on untreated siblings

The purpose of the present study was twofold: (a) to examine changes in parent behavior toward an untreated sibling after parent behavioral training to modify a target child's noncompliance and (b) to examine changes in the untreated sibling's behavior. Eight clinic- referred children and their mothers served as the subjects. Parent training consisted of the use of a standardized clinic program to modify child noncompliance. The outcome measure was home observations of the parent and untreated child's interactions. The results indicated significant changes in both the parent's behavior and the untreated sibling's noncompliance.