Efficient autoproteolytic processing of the MHV-A59 3C-like proteinase from the flanking hydrophobic domains requires membranes

The replicase gene of the coronavirus MHV-A59 encodes a serine-like proteinase similar to the 3C proteinases of picornaviruses. This proteinase domain is flanked on both sides by hydrophobic, potentially membrane-spanning, regions. Cell-free expression of a plasmid encoding only the 3C-like proteinase (3CLpro) resulted in the synthesis of a 29-kDa protein that was specifically recognized by an antibody directed against the carboxy-terminal region of the proteinase. A protein of identical mobility was detected in MHV-A59-infected cell lysates. In vitro expression of a plasmid encoding the 3CLpro and portions of the two flanking hydrophobic regions resulted in inefficient processing of the 29-kDa protein. However, the efficiency of this processing event was enhanced by the addition of canine pancreatic microsomes to the translation reaction, or removal of one of the flanking hydrophobic domains. Proteolysis was inhibited in the presence of N-ethylmaleimide (NEM) or by mutagenesis of the catalytic cysteine residue of the proteinase, indicating that the 3CLpro is responsible for its autoproteolytic cleavage from the flanking domains. Microsomal membranes were unable to enhance the trans processing of a precursor containing the inactive proteinase domain and both hydrophobic regions by a recombinant 3CLpro expressed from Escherichia coli. Membrane association assays demonstrated that the 29-kDa 3CLpro was present in the soluble fraction of the reticulocyte lysates, while polypeptides containing the hydrophobic domains associated with the membrane pelletes. With the help of a viral epitope tag, we identified a 22-kDa membrane-associated polypeptide as the proteolytic product containing the amino-terminal hydrophobic domain.     

Effects of cytosolic Ca2+ on the Ca2+ content of the sarcoplasmic reticulum in saponin-permeabilized rat ventricular trabeculae

After a brief presentation of the development of free walking interpreted as learning dynamical equilibrium, the problem of sensory integration in the process of walking development is discussed. A critical review of the role of vision in the development of posturo-locomotor task is presented, along with recent test results on the development of the vestibular system. A final section presents the development of head stabilization and coordination as a necessary means to assist sensory integration. It is suggested that if sensory information is necessary to enhance posturo-locomotor skills, a good mastery of walking is in turn necessary to increase the efficiency of sensory integration.     

Time-frequency analysis using the matching pursuit algorithm applied to seizures originating from the mesial temporal lobe

A Spanish-language questionnaire designed for measuring the impact of asthma on quality of life in adults was developed. It was derived, by the application of a rigorous translation protocol, from a previously validated, English-language Asthma Quality of Life (AQL) questionnaire which had been developed in Australia. The aim of this study was to evaluate the psychometric properties of the Spanish AQL questionnaire using a cross-sectional and longitudinal design. Two hundred ninety-four clinically stable subjects with asthma (168 women, mean baseline forced expiratory volume in 1 sec [FEV1] = 85% predicted), aged 17-70, attended for the initial baseline assessment. All subjects completed the AQL questionnaire and a full history and physical examination were performed. The clinical assessment of severity was based on the classification recommended by the Global Initiative on Asthma (GINA). One week after the initial assessment subjects completed the AQL questionnaire for a second time. Six months later, subjects were assessed clinically and completed all the assessment measures at baseline. Principal components analysis of the AQL questionnaire responses at the baseline visit revealed a structure that was almost identical to that seen in the original English-language questionnaire. The questionnaire was shown to be internally consistent (Cronbach's alpha 0.91 for total score and 0.80-0.86 for the four subscales) and repeatable (intraclass correlation coefficient 0.91 for the total scale and 0.78-0.92 for the subscales). The finding of expected strong correlations with the subject's global assessment of severity (p = 0.70) and dyspnea (p = 0.63), a weak inverse correlation with FEV1 (p = -0.17), and good discrimination among the four GINA severity categories (F3,291 = 37.16, p < 0.0001) supports the construct validity of the questionnaire. AQL scores increased with age (p = 0.31) and were higher in women (p < 0.005). The AQL was responsive to both improvement (mean change 1.02, p < 0.0001) and deterioration (mean change -1.13, p < 0.001) in the severity of asthma over a 6-month period. This disease-specific, Spanish-language AQL questionnaire was shown to have sound psychometric properties which make it suitable for use in cross-sectional or longitudinal studies where it is appropriate to assess the impact of asthma on the quality of life of individual patients.     

Growth factor involvement in progression of prostate cancer

Understanding how the regulation of growth factor pathways alters during prostate cancer (PC) progression may enable researchers to develop targeted therapeutic strategies for advanced disease. PC progression involves the shifting of cells from androgen-dependent growth to an androgen-independent state, sometimes with the loss or mutation of the androgen receptors in PC cells. Both autocrine and paracrine pathways are up-regulated in androgen-independent tumors and may replace androgens as primary growth stimulatory factors in cancer progression. Our discussion focuses on growth factor families that maintain homeostasis between epithelial and stromal cells in the normal prostate and that undergo changes as PC progresses, often making stromal cells redundant. These growth factors include fibroblast growth factor, insulin-like growth factors, epidermal growth factor, transforming growth factor alpha, retinoic acid, vitamin D3, and the transforming growth factor beta families. We review their role in normal prostate development and in cancer progression, using evidence from clinical specimens and models of PC cell growth.     

High-dose chemotherapy with autologous hematopoietic progenitor-cell support as part of combined modality therapy in patients with inflammatory breast cancer

PURPOSE: To evaluate the feasibility of high-dose chemotherapy (HDC) with autologous hematopoietic progenitor-cell support (AHPCS) as part of combined modality therapy (CMT) in patients with inflammatory breast cancer (IBC). PATIENTS AND METHODS: From April 1993 to March 1997, 30 patients with IBC were treated at our program. Twenty-three patients received neoadjuvant chemotherapy (NAC) before HDC; 18 patients also received adjuvant chemotherapy following surgery, but before HDC. All patients received HDC with high-dose cyclophosphamide, cisplatin, and carmustine (BCNU) with AHPCS. Every patient underwent surgery either before (27 patients) or after (three patients) HDC. Patients received radiotherapy after HDC in addition to tamoxifen if their tumors were estrogen receptor-positive. RESULTS: Thirteen patients experienced grade 3 or 4 nonhematologic noninfectious toxicities. In 12 patients (40%), this represented drug-induced lung injury, which in all cases responded to a 10-week course of corticosteroids. The only treatment-related death was secondary to hemolytic-uremic syndrome (HUS). Another patient suffered grade 4 CNS toxicity, which was completely reversible. All patients engrafted promptly. Eight patients relapsed, five of whom had a poor pathologic response to NAC. Relapses were local (five patients), local plus systemic (one), or systemic only (two). Median follow-up time from diagnosis and HDC is 23.5 (range, 7 to 49) and 19 (range, 4 to 44) months, respectively. Twenty-one patients (70%; 95% confidence interval [CI], 51% to 86%) remain alive and free of disease 4 to 44 months after HDC. Median disease-free survival (DFS) and overall survival have not yet been reached. CONCLUSION: HDC as part of CMT is feasible in patients with IBC. The toxicity of this treatment program is significant, but tolerable. Despite the short follow-up duration, the promising DFS observed in this group of patients warrants randomized studies that include a HDC-containing arm in patients with IBC.