BID: a novel BH3 domain-only death agonist

The BCL-2 family of proteins consists of both antagonists (e.g., BCL-2) and agonists (e.g., BAX) that regulate apoptosis and compete through dimerization. The BH1 and BH2 domains of BCL-2 are required to heterodimerize with BAX and to repress cell death; conversely, the BH3 domain of BAX is required to heterodimerize with BCL-2 and to promote cell death. To extend this pathway, we used interactive cloning to identify Bid, which encodes a novel death agonist that heterodimerizes with either agonists (BAX) or antagonists (BCL-2). BID possesses only the BH3 domain, lacks a carboxy-terminal signal-anchor segment, and is found in both cytosolic and membrane locations. BID counters the protective effect of BCL-2. Moreover, expression of BID, without another death stimulus, induces ICE-like proteases and apoptosis. Mutagenesis revealed that an intact BH3 domain of BID was required to bind the BH1 domain of either BCL-2 or BAX. A BH3 mutant of BID that still heterodimerized with BCL-2 failed to promote apoptosis, dissociating these activities. In contrast, the only BID BH3 mutant that retained death promoting activity interacted with BAX, but not BCL-2. This BH3-only molecule supports BH3 as a death domain and favors a model in which BID represents a death ligand for the membrane-bound receptor BAX.     

Predictive modelling of the 3-D structure of interleukin-13

Several atomic structures are now available for the family ofhelical cytokines, which includes growth hormone as well asmany of the interleukins. Using structural information fromfive members of this family, two alternative models of interleukin(IL)-13 are proposed. IL-13 has biological properties similarto those of IL-4 and, like the other interleukins, is a potentiallyimportant pharmaceutical target. The model of IL-13 is discussedand compared with the known interleukin structures.     

Routine use of ultrasound 24 hours before laparoscopic cholecystectomy can predict the need for intraoperative cholangiogram: results of a 12-month prospective audit

Progressive supranuclear palsy (PSP) is a progressive degenerative extrapyramidal disease that often masquerades as Parkinson's disease (PD). Similar to PD, dysphagia frequently complicates the course of PSP. Because there is only one published report characterizing dysphagia in PSP, we reviewed the neurologic features and dynamic videofluoroscopic swallowing function study results in 10 dysphagic PSP patients. Abnormalities during multiple stages of ingestion were recorded in each patient. Uncoordinated lingual movements, absent velar retraction or elevation, impaired posterior lingual displacement, and copious pharyngeal secretions were noted in all patients. Tongue-assisted mastication, noncohesive lingual transfer, excessive oral bolus lingual leakage to the pharynx prior to active transfer, vallecular bolus retention, abnormal epiglottic positioning, and hiatal hernias were noted in at least half of the cohort. Although ingestion abnormalities in PSP are similar to those previously reported in PD, the number of studied patients and observed differences were too few to clearly differentiate the two diseases.     

Late cytomegalovirus disease in marrow transplantation is predicted by virus load in plasma

Late occurrence of cytomegalovirus (CMV) disease after day 100 after bone marrow transplantation has become an increasing problem; whether a quantitative measurement of CMV DNA in plasma by polymerase chain reaction (P-PCR) could be predictive of such disease was investigated. In a prospective study, 117 subjects undergoing allogeneic marrow transplantation were followed for 120 days with weekly CMV blood cultures, with day 35 bronchoalveolar lavage CMV cultures, with weekly CMV P-PCR, and with clinical follow-up for an additional 1-2 years. Despite preemptive ganciclovir, CMV disease occurred in 9% of subjects, with a median time of onset of 176 days. Quantitative CMV P-PCR was associated with the late development of CMV disease (P = .01). Of 43 subjects with positive P-PCR results, 23% developed CMV disease, but no disease occurred in the 74 subjects with negative P-PCR (P < .001), despite the fact that 22% had CMV isolated from lung lavage fluid and 32% had CMV isolated from blood.     

The cement mantle in the Exeter impaction allografting technique. A cause for concern

The postoperative radiographs of 35 patients who underwent impaction allografting of the proximal femur were reviewed. Of Gruen zones that could be clearly visualized, 39.9% contained areas where cement was absent. Even when an adequate mantle was present, cement voids were commonly seen. These cement mantle deficiencies were confirmed in a series of cadaveric impaction allografting procedures. They appear to be a consequence, at least in part, of an inadequate differential between trial and actual component sizes. Additionally, 4 patients were identified with significant component migration secondary to radiographically visible cement mantle fractures within the first 6 months of surgery. It is concluded that the surgical technique requires modification to ensure a more consistent cement mantle and clinical result.     

The human SHIP gene is differentially expressed in cell lineages of the bone marrow and blood

The macrophage colony-stimulating factor receptor and several other hematopoietic growth factor receptors induce the tyrosine phosphorylation of a 145- to 150-kD protein in murine cells. We have previously cloned a cDNA for the murine 150-kD protein, SHIP, and found that it encodes a unique signaling intermediate that binds the SHC PTB domain through at least one tyrosine phosphorylated (NPXY) site in the carboxyl-terminal region. SHIP also contains several potential SH3 domain-binding sites, an SH2 domain for binding other tyrosine phosphorylated proteins, and an enzymatic activity that removes the phosphate from the 5 position of phosphatidylinositol 3,4,5-phosphate or from inositol 1,3,4,5-phosphate. SHIP has a negative effect on cell growth and therefore loss or modification may have profound effects on hematopoietic cell development. In this study, we have cloned a cDNA for human SHIP and examined mRNA and protein expression of SHIP and related species in bone marrow and blood cells. Flow cytometry indicates that at least 74% of immature CD34+ cells express SHIP cross-reacting protein species, whereas within the more mature population of CD33+ cells, only 10% of cells have similar expression. The majority of T cells react positively with the anti-SHIP antibodies, but significantly fewer B cells are positive. Immunoblotting detects up to seven different cross-reacting SHIP species, with peripheral blood mononuclear cells exhibiting primarily a 100-kD protein and a CD34+ acute myeloblastic leukemia expressing mainly 130-kD and 145-kD forms of SHIP. Overall, these results indicate that there is an enormous diversity in the size of SHIP or SHIP-related mRNA and protein species. Furthermore, the expression of these protein species changes according to both the developmental stage and differentiated lineage of the mature blood cell.     

Determination of glycyrrhizin and glycyrrhetinic acid in traditional Chinese medicinal preparations by capillary electrophoresis

A simple, rapid, accurate and reproducible capillary electrophoretic method was developed for the assay of glycyrrhizin and glycyrrhetinic acid in traditional Chinese medicinal preparations. The buffer solution used in this method was acetonitrile and 0.02 M sodium dihydrogen-phosphate solution adjusted to pH 7.5 with 0.05 M sodium hydroxide. The linear calibration range was 0.04-2.00 mg/ml (r = 0.9988) for glycyrrhizin and 0.007-0.35 mg/ml (r = 0.9985) for glycyrrhetinic acid and recoveries were 98.1-101.3% for glycyrrhizin and 98.5-101.4% for glycyrrhetinic acid. The relative standard deviations were 1.02% (n = 6) for glycyrrhizin and 0.91% (n = 6) for glycyrrhetinic acid. The content of these two acids in Glycyrrhizae Radix and Glycyrrhizae Radix-containing Chinese medicinal preparations was successfully determined within 10 min.