Human Brain Lectin: A Soluble Lectin That Binds Actin

A biotinylated probe was used for detection of endogenous ligands of a human brain lectin on blotted human brain soluble proteins. Of the various proteins from brain extract resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, five reacted with the biotinylated probe. After elimination of saccharidic moieties by periodic treatment of the same extract, a single band with Mr approximately 43,000 was recognized by the lectin. This band was identified as actin using an anti-actin antibody. These results were confirmed by binding of biotinylated lectin to purified actin.     

Cancer immunomics using autoantibody signatures for biomarker discovery

The increased incidence of autoantibodies in malignancies has been described since the 1970s. Thus the ability to determine molecular fingerprinting of autoantibodies (antibody signatures) may provide useful clinical diagnostic and prognostic information. This review describes the use of several proteomics approaches for the identification of antigens recognized by these autoantibodies. Serological proteome analysis combines separation of tumor cell proteins on two-dimensional gel electrophoresis gels, Western blotting with sera of patients and healthy subjects, and identification of the detected antigens by MS. Alternatively multiple affinity protein profiling combines isolation of the antigens recognized by patient antibodies by two-dimensional immunoaffinity chromatography and identification by MS/MS. The use and limitations of reverse phase protein microarrays for testing patient serum containing autoantibodies are also considered. Lastly the most important difficulty of any proteomically identified autoantibody signature is validation in patient cohorts or clinical samples.     

Sarco/endoplasmic reticulum Ca2+ATPase type 3 isoforms (SERCA3b and SERCA3f): distinct roles in cell adhesion and ER stress

Sarco/endoplasmic reticulum Ca(2+)ATPases (SERCAs) pump free Ca(2+) from the cytosol into the endoplasmic reticulum. The human SERCA3 family counts six members named SERCA3a to 3f. However, the exact role of these different isoforms in cellular physiology remains undetermined. In this study, we compared some physiological consequences of SERCA3b and SERCA3f overexpression in HEK-293 cells. We observed that overexpression of SERCA3b affected cell adhesion capacity associated with a major disorganization of F-actin and a decrease in focal adhesion. Furthermore, we found that SERCA3f overexpression resulted in an increase in endoplasmic reticulum stress markers (including processing of X-box-binding protein-1 (XBP-1) mRNA and expression of chaperone glucose-regulated protein 78 (GRP78)). This was associated with the activation of caspase cascade and a higher spontaneous cell death. In conclusion, these data point for the first time to distinct physiological roles of SERCA3 isoforms in cell functions.     

Changes in secondary structures and acidic side chains of melibiose permease upon cosubstrates binding

Infrared difference spectroscopy analysis of the purified melibiose permease of Escherichia coli reconstituted into liposomes was carried out as a function of the presence of the two symporter substrates (Na(+), melibiose) in either H(2)O or in D(2)O media. Essentially, the data first show that addition of Na(+) induces appearance of peaks assigned to changes in the environment and/or orientation of alpha-helical domains of purified melibiose permease. Likewise, melibiose addition in the presence of Na(+) produces peaks corresponding to additional changes of alpha-helix environment or tilt. In addition to these changes, a pair of peaks (1599 (+) cm(-1)/1576 (-) cm(-1)) appearing in the Na(+)-induced difference spectrum is assigned to the antisymmetric stretching of COO(-) groups, since they show practically no shift upon H/D exchange. It is proposed that these acidic groups participate in Na(+) co-ordination. A corresponding pair of peaks, again fairly insensitive to H/D substitution (1591 (-) cm(-1)/1567 (+) cm(-1)), appear in the melibiose-induced difference spectra, and may again be assigned to COO(-) groups. The latter carboxyl groups may correspond to part or all of the acidic residues interacting with Lys or Arg in the resting state that become free upon melibiose binding.     

Oligoclonal β-galactoside-specific γ immunoglobulins allow the immunocytochemical detection of cellular antigenic determinants expressed in mouse brain after surgical injury

Histological brain sections were probed with human oligoclonal lectin-like IgGs (L-IgG) purified from normal serum. In intact brain, antigenic determinants for these IgG were restricted to some blood vessel endothelial cells. By contrast, during the inflammatory reaction following a surgical injury, these determinants were detected at the cell surface of different cell types, within and near the lesion site. The cells reacting with L-IgG consisted of endothelial cell, mature astrocytes, activated microglial and ependymal cells.     

Sources and accumulation rates of organic carbon in an equatorial peat bog (Burundi, East Africa) during the Holocene: carbon isotope constraints

The relationship between organic carbon accumulation rates and ¹³C/¹²C ratios of total organic carbon (TOC) was investigated in an highland peat bog core (Ru-3) from Equatorial Africa. This core yielded a sequence spanning the last 14 kyr and was analysed with a 100–300 yr resolution for TOC-δ¹³C values. The Holocene section shows contrasted TOC accumulation regimes and TOC δ¹³C varying between −28.5 and −19.5‰ with a few very short ‘isotopic excursions' (dated at ca. 9.3, 7.5, 4.2 ka B.P.). The organic carbon accumulation rates range from 2 to 20 mg C cm⁻² yr⁻¹. They increase when TOC becomes more depleted in ¹³C, notably between 12 and 9.8 ka B.P., 8.5 and 7.8 ka B.P. and after 1.6 ka B.P. Periods of restricted carbon storage correspond to heavier TOC accumulation at 9.3, and between 7.5 and 1.6 ka B.P. At the study site, the δ-variations can be related to variable C4-plant inputs, and possibly, to changes in the fractionation between CO₂ and the organic carbon in C3 vascular plants. The Ru-3 record indicates restricted carbon storage during the periods of increased contribution from C4 plants and/or of decreased fractionation between CO₂ and organic carbon in C3 plants. Changes in TOC-δ¹³C values in core Ru-3 seem to match fluctuations of East Equatorial African lakes. High lake stands correspond to low δ¹³C intervals and vice versa. This points to indirect climatic forcing of δ¹³C changes in intertropical peats.     

Characterization of calcium liberation from a human platelet membrane fraction

Calcium efflux and EGTA-induced calcium release from an internal platelet membrane fraction have been studied after the oxalate-supported calcium uptake had reached steady state. Increasing external calcium concentrations stimulate the calcium efflux velocity, with an apparent half-maximal stimulation at about 5 μM outside calcium concentration and a maximal velocity of calcium efflux of $\text{4.66 ± 2.32}\text{nmol}\text{·}\text{min}{}^{\mathrm{?1}}\text{·}\text{mg}{}^{\mathrm{?1}}$. Moreover, the ratio of the liberated calcium on the loaded calcium seems to be independent of the increasing external calcium concentration. Increasing the calculated internal calcium concentration by varying the oxalate potassium concentration from 10 mM to 1 mM results in an increase of the liberated calcium from the membrane vesicles from 7.4% to 63%, respectively, without changing the calcium efflux velocity. Similar conclusions can be drawn from the observation of results from the calcium efflux and EGTA-induced calcium release methods. Moreover, calcium pump reversal does not seem to be responsible for the calcium efflux or calcium release. All these different points added to the previously described regulation of calcium efflux by the catalytic subunit of cAMP protein kinase suggest us that the mechanism of calcium liberation by the platelet membranes is different from the calcium uptake.     

Axonal Transport Reversal of Acetylcholinesterase Molecular Forms in Transected Nerve

Reversal of anterograde rapid axonal transport of four molecular forms of acetylcholinesterase (AChE) was studied in chick sciatic nerve during the 24-h period following a nerve transection. Reversal of AChE activity started ～1 h after nerve transection, and all the forms of the enzyme, except the monomeric ones, showed reversal of transport. The quantity of enzyme activity reversed 24 h after transection was twofold greater than that normally conveyed by retrograde transport. We observed no leakage of the enzyme at the site of the nerve transection and no reversal of AChE activity transport in the distal segment of the severed nerve, a result indicating that the material carried by retrograde axonal transport cannot be reversed by axotomy. Thus, a nerve transection induces both quantitative and qualitative changes in the retrograde axonal transport, which could serve as a signal of distal injury to the cell body. The velocity of reverse transport, measured within 6 h after transection, was found to be 213 mm/day, a value close to that of retrograde transport (200 mm/day). This suggests that the reversal taking place in severed sciatic nerve is similar to the anterograde-to-retrograde conversion process normally occurring at the nerve endings.     

Traitement par ultrasons focalisés du cancer localisé de la prostate: Résultats carcinologiques et pronostic sexuel

Introduction

Since 1999, a therapeutic device using High Intensity Focused Ultrasound (HIFU) technology has been marketed in Europe for the treatment of localized prostate cancer. Clinical and technical development was designed to provide a minimally invasive alternative for these patients. The purpose of this study was to evaluate the efficacy of HIFU therapy for localized prostate cancer and its impact on sexual function.

Material and Methods

HIFU technology is based on a convergent beam of high intensity ultrasound that creates a sudden and sharp increase in temperature (85°C to 100°C) in the tissues at the focal point. This leads to a precise lesion in the tissue, adjustable from 19 to 24 mm in height and 2 mm in diameter. Successive displacements of the focal point are computer-driven, allowing treatment of a defined volume. All patients were treated with the ABLATHERM® device (EDAP SA, France); they were treated using the device prototypes between 1993 to 1999 and then with the marketed machine. The treatment procedure was improved from 2000 onwards with the combination of transurethral resection of the prostate (TURP) in order to reduce post-treatment catheter time. A nerve-sparing procedure was also tested in 2002. The selected population included 120 patients considered to be potentially curable with clinical stage T1–T2 prostate cancer and an initial PSA < 10 ng/ml (group 1). A larger group of 167 patients with an initial PSA < 30 ng/ml was also considered (group 2). All patients were not candidates for surgery due to their age or comorbidities. In the two groups, clinical failure was defined by the need for administration of an adjuvant prostate cancer treatment (hormone deprivation or external radiation). Disease progression, or biochemical failure, was strictly defined as any evidence of residual cancer on follow-up biopsies (regardless of the PSA level), or 3 successive increases of the PSA level (with negative follow-up biopsies), with a velocity > 0.75 ng/ml/year. Disease-free survival rates were calculated using the Kaplan-Meier method. Survival rates were compared using the log-rank test. The impact of HIFU treatment on sexual function was assessed by a questionnaire in 70 patients who underwent standard HIFU treatment and in 28 patients in whom a nerve-sparing procedure was performed.

Results

Patient baseline characteristics (± SD) were, in group 1 and group 2 respectively: mean age: 71.2 (± 5.34) years and 71.8 (± 5.11) years; clinical stage: T1 for 61 patients and T2 for 59 patients in group 1, and T1 for 77 patients, T2 for 85 patients and T3 for 5 patients in group 2; mean initial PSA level: 5.67 (± 2.47) ng/ml and 9.30 (± 6.01) ng/ml; Gleason score: 2–6 for 77 patients and 7–10 for 43 patients in group 1, and 2–6 for 98 patients, 7 for 44 patients, and 8–10 for 25 patients in group 2; mean prostate volume: 33.6 (± 16.5) ml and 34.4 (± 16.7) ml, respectively. Mean follow-up was 27 months (range: 3–96 months) in group 1, and 23 months (range: 3–90 months) in group 2. In group 1, a residual cancer was diagnosed in 17 patients, but only 6 patients needed adjuvant treatment due to a significant rise of the PSA level (hormone deprivation: n=2, external radiation: n=4), leading to a clinical success rate of 95%. Similarly, in group 2, 36 patients presented with positive follow-up biopsies, and 21 of them required adjuvant treatment (hormone deprivation: n=10, external radiation: n=11), leading to a clinical success rate of 87.5%. The disease-free survival rates (previously defined on the combined biopsy and PSA criteria) were 76.9% and 66% in group 1 and 2, respectively. In addition, the disease-free survival rate in group 2 was stratified according to the initial prognosis risk level: 85% in low-risk patients (i.e. patients with clinical stage T1–T2a and PSA < 10 ng/ml and Gleason score < 7), 67.5% in intermediate-risk patients (i.e. clinical stage T2b or PSA 10–20 ng/ml or Gleason score = 7), and 42% in high-risk patients (i.e. clinical stage T2c or PSA > 20 ng/ml or Gleason score > 7). In the overall population, 70 patients had normal sexual function prior to HIFU treatment; 25 patients (36%) still had erections allowing sexual intercourse with penetration after treatment. A nerve-sparing procedure was also performed in 28 potent patients: 43% of these patients had persistent erections allowing sexual intercourse with penetration after treatment, indicating that this nerve-sparing procedure still needs to be improved.

Conclusion

The efficacy results observed after HIFU treatment are similar to those observed after other non-surgical treatments for prostate cancer. After complete HIFU treatment of the gland, more than 1/3 of patients still reported erections allowing sexual intercourse with penetration; these results must be interpreted for an elderly population (mean age: 72 years). A nerve-sparing procedure is currently being perfected and tested.