The effect of cryogenic storage on human erythrocyte membrane proteins as determined by polyacrylamide-gel electrophoresis

A study was conducted to determine the effects of freezing on the major membrane proteins of isolated human erythrocyte membranes. Membranes in low or normal ionic strength medium were frozen at slow or fast freezing rates. The membrane protein composition and elution of proteins from the membranes were studied utilizing polyacrylamide-gel electrophoresis in a sodium dodecyl sulfate or an acetic acid-urea-phenol solvent system. Neither a change in the composition of the membrane proteins nor any elution of membrane protein during freezing and thawing was observed. The data indicate that any human erythrocyte membrane damage during freezing and thawing was not related to a change in major membrane protein composition. Human red cell membranes were stable at ?80 or ?196 °C in the absence of a cryoprotective agent.     

Wave-Processing of Long-Scale Information by Neuronal Chains

Investigation of mechanisms of information handling in neural assemblies involved in computational and cognitive tasks is a challenging problem. Synergetic cooperation of neurons in time domain, through synchronization of firing of multiple spatially distant neurons, has been widely spread as the main paradigm. Complementary, the brain may also employ information coding and processing in spatial dimension. Then, the result of computation depends also on the spatial distribution of long-scale information. The latter bi-dimensional alternative is notably less explored in the literature. Here, we propose and theoretically illustrate a concept of spatiotemporal representation and processing of long-scale information in laminar neural structures. We argue that relevant information may be hidden in self-sustained traveling waves of neuronal activity and then their nonlinear interaction yields efficient wave-processing of spatiotemporal information. Using as a testbed a chain of FitzHugh-Nagumo neurons, we show that the wave-processing can be achieved by incorporating into the single-neuron dynamics an additional voltage-gated membrane current. This local mechanism provides a chain of such neurons with new emergent network properties. In particular, nonlinear waves as a carrier of long-scale information exhibit a variety of functionally different regimes of interaction: from complete or asymmetric annihilation to transparent crossing. Thus neuronal chains can work as computational units performing different operations over spatiotemporal information. Exploiting complexity resonance these composite units can discard stimuli of too high or too low frequencies, while selectively compress those in the natural frequency range. We also show how neuronal chains can contextually interpret raw wave information. The same stimulus can be processed differently or identically according to the context set by a periodic wave train injected at the opposite end of the chain.     

Evaluation of five elements in lenses and aqueous humour of experimental rabbits after induced opacity

We evaluated the presence of Ca, Na, K, Cu and Zn in the lenses and aqueous humour of rabbits treated with an Nd:YAG laser to induce opacity of the crystalline. The mean concentrations of the elements found in control lenses were: Ca: 15.8+/-5.2 mg/kg; Na: 1.2+/-0.6 g/kg; K: 10.3+/-3.3 g/kg; Cu: 0.19+/-0.06 mg/kg; Zn: 20.6+/-3.0 mg/kg. With the exception of K and Zn, the values found in the lenses of treated eyes (Ca: 135+/-24 mg/kg; Na: 4.3+/-1.5 g/kg; K: 10.1 +/- 3.2 g/kg; Cu: 0.47+/-0.17 mg/kg; Zn: 21.8+/-4.2 mg/kg) were significantly higher than in the controls. On the other hand, the concentrations found in the aqueous humour of treated eyes (Ca: 21.7+/-4.5 mg/l; Na: 0.66+/-0.21 g/l; K: 0.29+/-0.10 g/l; Cu: 0.035+/-0.009 mg/l; Zn: 0.079+/-0.01 mg/l) were significantly lower than those of the controls. The greatest difference was observed for Na (-68.6%) and Cu (-52.7%), followed by Ca and Zn (-35.0% and -35.2%, respectively). A positive correlation was found between Ca and Na in treated lenses (r2 = 0.9226, p < 0.0001) whereas inverse correlations were found for both Ca (r2 = 0.9788, p<0.0001) and Na (r2 = 0.9491, p<0.0001) between the concentrations found in the lenses and in the aqueous humour of treated eyes.     

The Arrival of Siberian Ancestry Connecting the Eastern Baltic to Uralic Speakers further East

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Salivary duct carcinoma of the parotid gland: report of a rare case with a comparative study of aspiration cytology and histomorphology

BACKGROUND: Salivary duct carcinomas affecting primarily the parotid gland are extremely rare (0.2-2% of all salivary gland tumors). These carcinomas are considered to be of high grade malignancy, with mortality in up to 70% of cases. They usually affect elderly males and less often young adults. Despite the fact that the histomorphologic characteristics of this tumor are always necessary for its classification, several authors have reported that the cytopathologic approach, using fine needle aspiration (FNA) cytology, can establish the final diagnosis. The aim of this paper is to present a rare case of salivary duct carcinoma of the parotid gland with no typical microscopic findings that was diagnosed by FNA cytology through a combination of techniques on biopsy material. CASE: A 56-year-old male presented with a right parotid mass measuring 6 cm in diameter. The mass appeared to expand subcutaneously and infiltrate the skin of the neck region. Biopsy material from both the mass and skin was obtained using FNA and processed with conventional, cell block and liquid-based cytology techniques. A core biopsy was also performed on the mass for histologic evaluation. CONCLUSION: The findings were consistent with a salivary duct carcinoma of the parotid gland and were confirmed by the histologic report. FNA cytology combined with such techniques as liquid-based cytology provides the potential for the final diagnosis. Liquid-based cytology can improve the cellular morphology of the material and allows immunocytochemistry and other diagnostic techniques. The application of such techniques is significantly restricted by conventional processing; thus, combining liquid-based cytology with other techniques expands the boundaries of cytology as a diagnostic test.     

A rat monoclonal antibody that catalyses the hydrolysis of a nitrophenyl-beta-lactam

We report the first example of a monoclonal antibody-catalysed hydrolysis of a beta-lactam where the antibodies were generated by a simple transition-state analogue. A rat monoclonal antibody (1/91c/4d/26) generated by using an acyclic 4-nitrophenylphosphate immunogen catalysed the hydrolysis of corresponding 4-nitrophenyl carbonates but, more importantly, also catalysed the hydrolysis of N-(4-nitrophenyl)-azetidinone at pH 8 with k(cat)=8.7 x 10(-6)s(-1) and K(M)=35 microM. This is the first example of a rat monoclonal catalytic antibody.     

Interstitial ATP level and degradation in control and postmyocardial infarcted rats

With the aim of estimating interstitial levels and the breakdownprocess of ATP, cardiac microdialysis was performed in the leftventricular wall of in situ control and postinfarcted as well as ofisolated, Langendorff-perfused rat hearts. With the use of abioluminescence technique for dialysate ATP measurement, the baselineinterstitial fluid ATP concentration in in situ hearts was estimated tobe 38 ± 8 nM. Regional ischemia induced an early peakincrease in interstitial fluid ATP to 373 ± 73 nM thatcorrelates with the maximal incidence of ventricular arrhythmias.During continuous infusion of individual adenine nucleotides (50 µMATP, ADP, or AMP), the dialysate samples were analyzed for adenine nucleotides, nucleosides, and bases using HPLC with ultraviolet detection. The patterns of catabolites were consistent with the majorpathway of metabolism, that is, sequential dephosphorylation catalyzedby a chain of separate ecto-nucleotidases. In in situ postinfarctedhearts as well as in perfused hearts, a reduced catabolism rate ofextracellular adenine nucleotides was observed. In conclusion, in insitu rat hearts, ATP can be released in substantial amounts in theinterstitium where it readily undergoes enzymatic degradation.Dephosphorylation occurs sequentially and faster in in situ controlhearts than in in situ postinfarcted or in perfused hearts.

     

Facile and Efficient Preparation of Tri-component Fluorescent Glycopolymers via RAFT-controlled Polymerization

Synthetic glycopolymers are instrumental and versatile tools used in various biochemical and biomedical research fields. An example of a facile and efficient synthesis of well-controlled fluorescent statistical glycopolymers using reversible addition-fragmentation chain-transfer (RAFT)-based polymerization is demonstrated. The synthesis starts with the preparation of β-galactose-containing glycomonomer 2-lactobionamidoethyl methacrylamide obtained by reaction of lactobionolactone and N-(2-aminoethyl) methacrylamide (AEMA). 2-Gluconamidoethyl methacrylamide (GAEMA) is used as a structural analog lacking a terminal β-galactoside. The following RAFT-mediated copolymerization reaction involves three different monomers: N-(2-hydroxyethyl) acrylamide as spacer, AEMA as target for further fluorescence labeling, and the glycomonomers. Tolerant of aqueous systems, the RAFT agent used in the reaction is (4-cyanopentanoic acid)-4-dithiobenzoate. Low dispersities (≤1.32), predictable copolymer compositions, and high reproducibility of the polymerizations were observed among the products. Fluorescent polymers are obtained by modifying the glycopolymers with carboxyfluorescein succinimidyl ester targeting the primary amine functional groups on AEMA. Lectin-binding specificities of the resulting glycopolymers are verified by testing with corresponding agarose beads coated with specific glycoepitope recognizing lectins. Because of the ease of the synthesis, the tight control of the product compositions and the good reproducibility of the reaction, this protocol can be translated towards preparation of other RAFT-based glycopolymers with specific structures and compositions, as desired.     

Bcr/Abl interferes with the Fanconi anemia/BRCA pathway: implications in the chromosomal instability of chronic myeloid leukemia cells

Chronic myeloid leukemia (CML) is a malignant clonal disorder of the hematopoietic system caused by the expression of the BCR/ABL fusion oncogene. Although it is well known that CML cells are genetically unstable, the mechanisms accounting for this genomic instability are still poorly understood. Because the Fanconi anemia (FA) pathway is believed to control several mechanisms of DNA repair, we investigated whether this pathway was disrupted in CML cells. Our data show that CML cells have a defective capacity to generate FANCD2 nuclear foci, either in dividing cells or after DNA damage. Similarly, human cord blood CD34(+) cells transduced with BCR/ABL retroviral vectors showed impaired FANCD2 foci formation, whereas FANCD2 monoubiquitination in these cells was unaffected. Soon after the transduction of CD34(+) cells with BCR/ABL retroviral vectors a high proportion of cells with supernumerary centrosomes was observed. Similarly, BCR/ABL induced a high proportion of chromosomal abnormalities, while mediated a cell survival advantage after exposure to DNA cross-linking agents. Significantly, both the impaired formation of FANCD2 nuclear foci, and also the predisposition of BCR/ABL cells to develop centrosomal and chromosomal aberrations were reverted by the ectopic expression of BRCA1. Taken together, our data show for the first time a disruption of the FA/BRCA pathway in BCR/ABL cells, suggesting that this defective pathway should play an important role in the genomic instability of CML by the co-occurrence of centrosomal amplification and DNA repair deficiencies.