Molecular characterization of a new ALK translocation involving moesin (MSN-ALK) in anaplastic large cell lymphoma

The majority of anaplastic large cell lymphomas (ALCL) are associated with chromosomal abnormalities affecting the anaplastic lymphoma kinase (ALK) gene which result in the expression of hybrid ALK fusion proteins in the tumor cells. In most of these tumors, the hybrid gene comprises the 5' region of nucleophosmin (NPM) fused in frame to the 3' portion of ALK, resulting in the expression of the chimeric oncogenic tyrosine kinase NPM-ALK. However, other variant rearrangements have been described in which ALK fuses to a partner other than NPM. Here we have identified the moesin (MSN) gene at Xq11-12 as a new partner of ALK in a case of ALCL which exhibited a distinctive membrane-restricted pattern of ALK labeling. The hybrid MSN-ALK protein had a molecular weight of 125 kd and contained an active tyrosine kinase domain. The unique membrane staining pattern of ALK is presumed to reflect association of moesin with cell membrane proteins. In contrast to other translocations involving the ALK gene, the ALK breakpoint in this case occurred within the exonic sequence coding for the juxtamembrane portion of ALK. Identification of the genomic breakpoint confirmed the in-frame fusion of the whole MSN intron 10 to a 17 bp shorter juxtamembrane exon of ALK. The breakpoint in der(2) chromosome showed a deletion, including 30 bp of ALK and 36 bp of MSN genes. These findings indicate that MSN may act as an alternative fusion partner for activation of ALK in ALCL and provide further evidence that oncogenic activation of ALK may occur at different intracellular locations.     

Increased adipocyte apoptosis in lipoatrophy improves within 48 weeks of switching patient therapy from Stavudine to abacavir or zidovudine

OBJECTIVES: Lipoatrophy is an important manifestation of the lipodystrophy syndrome and is particularly associated with stavudine exposure. Increased apoptosis has been suggested as a possible mechanism of lipoatrophy. We assessed the degree and reversibility of adipocyte apoptosis in patients with lipoatrophy before and 48 weeks after substituting abacavir or zidovudine for stavudine. METHODS: Apoptotic adipocytes were identified using terminal transferase dUTP nick end labeling and quantified using video image analysis. RESULTS: Fat biopsy specimens were obtained from patients before (n = 15) and 48 weeks after (n = 10) switching from stavudine and from 20 HIV-uninfected controls. More apoptotic cells were seen in fat samples from patients with lipoatrophy treated with stavudine than in specimens from controls (P < 0.0001). Forty-eight weeks after switching from stavudine to abacavir or zidovudine, there was a reduction in apoptotic cells per unit area (P = 0.01) and as a proportion of all adipocytes present (P = 0.02) in patient biopsy specimens. Levels of adipocyte apoptosis in the 48-week biopsy specimens were no longer significantly different from those seen in control biopsy specimens (P > 0.1). CONCLUSIONS: Increased apoptosis is present in fat samples from patients with lipoatrophy treated with stavudine. This improves toward normal within 48 weeks of switching from stavudine to abacavir or zidovudine, suggesting a causative role for stavudine in this process.     

New Granada Medium for detection and identification of group B streptococci.

A methotrexate-containing medium for the detection of beta-hemolytic group B streptococci from clinical specimens on the basis of detection of pigment is described. The medium contained peptone, starch, serum, MgSO4, glucose, pyruvate, methotrexate (as pigment enhancer), phosphate-morpholine-propanesulfonic acid buffer, and selective agents. The recovery of beta-hemolytic group B streptococci was comparable to that obtained with selective broth.     

Biocompatibility of NDGA-polymerized collagen fibers. I. Evaluation of cytotoxicity with tendon fibroblasts in vitro

The material properties of tendon type I collagen fibers polymerized with nordihydroguaiaretic acid (NDGA) are equivalent to native tendon, suggesting that NDGA crosslinking may provide a viable approach to stabilizing collagenous materials for repairing ruptured, lacerated, or surgically transected fibrous tissues, such as tendon and ligament (Koob & Hernandez, Biomaterials, in press). Using standard cytotoxicity tests, the present study evaluated the biocompatibility of these fibers with cultured bovine tendon fibroblasts. Primary fibroblasts obtained from calf digital extensor tendons were exposed to NDGA, reaction products generated from the polymerization protocol, and the crosslinked fibers. NDGA was cytotoxic to these cells at concentrations above 100 microM. NDGA oxidation products were similarly cytotoxic. At concentrations below 100 microM, fibroblast viability was not affected by NDGA or its oxidation products. At these lower concentrations, fibroblast proliferation was unaffected compared to controls not exposed to NDGA. Fibers crosslinked with NDGA contained no unreacted NDGA, but they did contain soluble reaction products that were cytotoxic to tendon fibroblasts in both the elution and the direct contact tests. Washing the fibers in 70% ethanol and phosphate-buffered saline eliminated cytotoxicity of the fibers. Ethanol simultaneously sterilized the fibers. Tensile tests established that the ethanol/phosphate buffer wash did not adversely affect the material properties of the fibers. The results of these experiments indicate that NDGA-crosslinked fibers can be rendered nontoxic to tendon fibroblasts and may provide a novel approach for producing biologically based, biocompatible, tendon bioprostheses.     

Rhubarb-based Chinese herbal formulae for hepatic encephalopathy: a systematic review and Meta-analysis

Objective

To evaluate the effectiveness and safety of rhubarb-based Chinese herbal formulae (RCHF), which are widely used to treat hepatic encephalopathy (HE) in China.