Imagining and constraining ferrovolcanic eruptions and landscapes through large-scale experiments.

Ferrovolcanism, yet to be directly observed, is the most exotic and poorly understood predicted manifestation of planetary volcanism. Large-scale experiments carried out at the Syracuse Lava Project offer insight into the emplacement dynamics of metallic flows as well as coeval metallic and silicate flows. Here, we find that, under the same environmental conditions, higher-density/lower-viscosity metallic lava moves ten times faster than lower-density/higher-viscosity silicate lava. The overall morphology of the silicate flow is not significantly affected by the co-emplacement of a metallic flow. Rather, the metallic flow is largely decoupled from the silicate flow, occurring mainly in braided channels underneath the silicate flow and as low-relief breakouts from the silicate flow front. Turbulent interactions at the metallic-silicate flow interface result in mingling of the two liquids, preserved as erosional surfaces and sharp contacts. The results have important implications for the interpretation of possible ferrovolcanic landscapes across our solar system.

Clinical outcomes of proximal row carpectomy versus four-corner arthrodesis for post-traumatic wrist arthropathy: a systematic review.

We conducted a systematic review of studies reporting clinical outcomes after proximal row carpectomy or to four-corner arthrodesis for scaphoid non-union advanced collapse or scapholunate advanced collapse arthritis. Seven studies (Levels I-III; 240 patients, 242 wrists) were evaluated. Significantly different post-operative values were as follows for four-corner arthrodesis versus proximal row carpectomy groups: wrist extension, 39 (SD 11º) versus 43 (SD 11º); wrist flexion, 32 (SD 10º) versus 36 (SD 11º); flexion-extension arc, 62 (SD 14º) versus 75 (SD 10º); radial deviation, 14 (SD 5º) versus 10 (SD 5º); hand grip strength as a percentage of contralateral side, 74% (SD 13) versus 67% (SD 16); overall complication rate, 29% versus 14%. The most common post-operative complications were non-union (grouped incidence, 7%) after four-corner arthrodesis and synovitis and clinically significant oedema (3.1%) after proximal row carpectomy. Radial deviation and post-operative hand grip strength (as a percentage of the contralateral side) were significantly better after four-corner arthrodesis. Four-corner arthrodesis gave significantly greater post-operative radial deviation and grip strength as a percentage of the opposite side. Wrist flexion, extension, and the flexion-extension arc were better after proximal row carpectomy, which also had a lower overall complication rate.

Production of chick germline chimeras from fluorescence-activated cell-sorted gonocytes.

Modification of the chicken germline has been difficult, because it has been challenging to fractionate sufficient numbers of primordial germ cells for manipulation and implantation into developing embryos. A technique to enrich cell suspensions for primordial germ cells, using fluorescence-activated cell sorting (FACS), has recently been developed. The objective of the current study was to demonstrate that the FACS-enriched early embryonic gonocytes could fully participate in development of the germline. Therefore, cells were disassociated from stage 27 gonads, incubated with mouse anti-stage-specific embryonic antigen-1, which was detected with goat-antimouse IgM-fluorescein isothiocyanate, and the fluorescently labeled cells were sorted from the unlabeled cells using FACS. The isolated gonocyte population was injected into the blastoderm of unincubated stage X embryos, the germinal crescent of 3-d embryos, and into the circulation of stage 17 embryos that were pretreated with busulfan. Barred Plymouth Rock gonocytes were implanted exclusively into recipient White Leghorn embryos, and White Leghorn gonocytes were implanted exclusively into Barred Plymouth Rock recipient embryos. Embryos were cultured until hatch, and male putative chimeras were reared to sexual maturity. Germline chimerism was evaluated by observing feather color of the progeny. All injection methods resulted in germline chimeras demonstrating that FACS-sorted gonocytes can fully participate in development. Moreover, it was demonstrated that gonocytes isolated from stage 27 embryonic gonads can be introduced into embryos at an earlier stage of development, and the introduced gonocytes can fully participate in germline development.

Mechanisms involved in metalloid transport and tolerance acquisition.

Toxic metalloids such as arsenic and antimony have always been an integral part of the natural environment. To survive in such a hostile habitat, it is crucial to develop strategies to exclude toxic substances from the cell and to acquire tolerance. Cells remove metalloids from the cytosol either by active efflux or by sequestration in an internal organelle. Controlling the influx appears to be another way of maintaining a low intracellular metalloid content. Inside the cell, the metalloid can be reduced to a form that is recognised by the expulsion system(s). In addition, metalloid complexation and compartmentalisation contributes to enhanced cellular tolerance. Finally, the presence of metalloids activates transcription of various cellular defence genes. Metalloid-containing drugs are currently used to treat protozoan infections and promyelocytic leukaemia. Since metalloid resistance hampers efficient treatment, interest in identifying the mechanisms involved in tolerance acquisition has arisen. The possibility of using genetic approaches has made the yeast Saccharomyces cerevisiae a compelling model system to investigate the basis of metalloid tolerance at a molecular level. This review describes the recent progress made in elucidating the mechanisms involved in metalloid transport and tolerance in yeast and other organisms.

Yap1 overproduction restores arsenite resistance to the ABC transporter deficient mutant ycf1 by activating ACR3 expression.

Ycf1 and Acr3 are transporters that have been previously shown to protect Saccharomyces cerevisiae cells from the toxic effects of arsenite. Ycf1 and Acr3 are positively regulated by distinct, but related bZIP transcriptional activators, Yap1 and Yap8, respectively. In this study, we show that overexpression of Yap1 complemented the arsenite hypersensitivity of the ycf1 null mutant, but only if the ACR3 gene is functional. We further show that the expression of either an ACR3-lacZ promoter fusion reporter or the endogenous ACR3 gene was stimulated by the overproduction of Yap1 upon exposure to arsenite. These data suggest that Yap1 confers arsenite resistance to the ycf1 null mutant by activating expression of the Yap8-dependent target gene, ACR3. Our data also show Yap8-dependent ACR3-lacZ expression was greatly stimulated by arsenite in a dose-dependent manner in the parental strain. However, overproduction of Yap1 in the parental strain severely limited dose-dependent activation of the reporter by arsenite. We conclude that Yap1 may compete with Yap8 for binding to the ACR3 promoter, but is unable to act as a potent activator.

The glycerol channel Fps1p mediates the uptake of arsenite and antimonite in Saccharomyces cerevisiae.

The Saccharomyces cerevisiae FPS1 gene encodes a glycerol channel protein involved in osmoregulation. We present evidence that Fps1p mediates influx of the trivalent metalloids arsenite and antimonite in yeast. Deletion of FPS1 improves tolerance to arsenite and potassium antimonyl tartrate. Under high osmolarity conditions, when the Fps1p channel is closed, wild-type cells show the same degree of As(III) and Sb(III) tolerance as the fps1Delta mutant. Additional deletion of FPS1 in mutants defective in arsenite and antimonite detoxification partially suppresses their hypersensitivity to metalloid salts. Cells expressing a constitutively open form of the Fps1p channel are highly sensitive to both arsenite and antimonite. We also show by direct transport assays that arsenite uptake is mediated by Fps1p. Yeast cells appear to control the Fps1p-mediated pathway of metalloid uptake, as expression of the FPS1 gene is repressed upon As(III) and Sb(III) addition. To our knowledge, this is the first report describing a eukaryotic uptake mechanism for arsenite and antimonite and its involvement in metalloid tolerance.

Western blotting versus ELISA detection of stress proteins induced in the blue mussel Mytilus edulis exposed to cadmium and tributyltin.

Stress proteins of the Hsp70 family induced in the blue mussel Mytilus edulis exposed in the laboratory to increased concentrations of cadmium (Cd) or tributhyltin (TBT) were analysed using Western blotting and/or ELISA tests. Statistical evaluation of results indicated that increased concentrations of Hsp70 were detected by means of the ELISA tests as compared with control organisms in extracts from the gills of mussels exposed to both Cd or TBT (p = 0.022). Results of analysis by means of Western blotting showed no differences in the levels of Hsp70 in the extracts (p = 0.151). It was concluded that the ELISA test allowed a more sensitive detection of Hsp70 than did Western blotting.

Systematic disruption of 456 ORFs in the yeast Saccharomyces cerevisiae.

In the framework of the European Network for Functional Analysis (EUROFAN), five packages of 96 ORFs from chromosomes III, IV, VII, XIII, XIV and XV were subjected to systematic deletions in an isogenic derivative of strain S288c. Deletions were constructed in diploid and haploid strains. Two questionable ORFs overlapping with larger ORFs and seven TY ORFs were discarded. A total of 456 heterozygous and 385 homozygous deletant diploids were obtained. Sixty-nine deletions, 25 of which had never been published before, were lethal in haploid strains and 30 caused slow cellular growth.

[Compensatory mechanisms of food transmission and lower respiratory tract protection after classical and extended supraglottic laryngectomies. Computerized topokinetic analysis of roentgen-cinematographic images]. / Mechanizmy kompensacyjne przewodzenia pokarmów i ochrony dolnych dróg oddechowych po klasycznych i poszerzonych laryngektomiach nadglosniowych. Komputerowa analiza topokinetyczna obrazów rentgenokinematograficznych.

Studies were performed on 22 patients, aged from 17 to 78 years, in whom, owing to laryngeal cancers, partly classical or extended supraglottic laryngectomy was carried out. The evaluation involving the pharyngeal deglutition course was accomplished by resorting to computerized topokinetic analysis of the roentgen-cinematographic images. The completed observation revealed good mobility of the anatomical structures participating in deglutition, small volume and number of glossolaryngeal recesses. There were few patients in whom the contrast medium passed to the trachea. Better passage of food as well as protection of lower respiratory tract were associated with the improvement of parameters facilitating the deglutition.

Functional characterization of the S. cerevisiae genome by gene deletion and parallel analysis.

The functions of many open reading frames (ORFs) identified in genome-sequencing projects are unknown. New, whole-genome approaches are required to systematically determine their function. A total of 6925 Saccharomyces cerevisiae strains were constructed, by a high-throughput strategy, each with a precise deletion of one of 2026 ORFs (more than one-third of the ORFs in the genome). Of the deleted ORFs, 17 percent were essential for viability in rich medium. The phenotypes of more than 500 deletion strains were assayed in parallel. Of the deletion strains, 40 percent showed quantitative growth defects in either rich or minimal medium.

[Mechanisms smoothing deglutition disorders after oral cancer surgery]. / Mechanizmy lagodzace zaburzenia polykania po wycieciu nowotworu jamy ustnej.

Compensatory treatment for oropharyngeal dysphagia includes postural changes and reducing the risk of aspiration. Some of compensatory maneuvers are introduced spontaneously by the ill at first weeks after oral cavity tumour resection. On the basis of roentgenotelevision examination of deglutition in 82 patients we detected mechanisms with intention to minimize swallowing disturbances. Variability of their occurrence and differences in their efficiency should be emphasized, as well as essential synchronization of laryngeal closure with emptying of pharynx and opening upper oesophageal sphincter for swallowing efficiency. The valuation of compensatory maneuvers introduced spontaneously by the ill was defined as an important part of swallowing rehabilitation.

Mass-murdering: deletion of twenty-three ORFs from Saccharomyces cerevisiae chromosome XI reveals five genes essential for growth and three genes conferring detectable mutant phenotype.

In the frame of the European Network for Functional Analysis (EUROFAN), two regions from chromosome XI covering 54kb have been subjected to 'mass-murder'. Ten deletions covering 23 novel open reading frames (ORFs) were constructed in haploid and diploid strains. Six deletions were lethal in haploid strains. One deletion caused slow germination of spores and slow cellular growth, and another one was associated with both cellular growth thermosensitivity and poor growth on glycerol. These two defects were assigned to two different genes. All mutant phenotypes were complemented by a single gene, enabling us to identify five genes essential for vegetative growth, three genes with detectable phenotype and 15 dispensable genes under standard physiological conditions.

Disruption and basic phenotypic analysis of 18 novel genes from the yeast Saccharomyces cerevisiae.

In the frame of the European Network for Functional Analysis (EUROFAN) we have deleted 18 yeast open reading frames (ORFs) from chromosomes II, X and XIV using the short flanking homology-PCR strategy. Two diploid strains were used: FY1679 and CEN.PK2. The deletion kanMX6 cassettes with long flanking homology and the cognate gene clones have also been constructed. Heterozygous diploid deletant strains have been sporulated. Tetrad analysis revealed that all the ORFs studied were non-essential. However, four deletant strains exhibited phenotypes. The YBL025w delta strain showed extremely slow cellular growth under all conditions tested. The YJL204c delta strain grew slower than wild-type at 30 degrees C and 37 degrees C, was cold-sensitive, and the homozygous diploids did not sporulate. The YNL213c delta strain did not grow on glycerol and had lost mitochondrial DNA. The deletion of YNL215w caused slower growth on all media but the defect was more pronounced on glucose-minimal and glycerol-rich media than on glucose-rich medium. All deletion mutants were complemented by the corresponding plasmid borne cognate gene. The YJL204w, YNL213c and YNL215w ORFs do not bear significant homology to proteins of known function. YBL025w has recently been identified as RRN10, a gene that encodes an RNA polymerase I-specific transcription initiator factor. The deletion of the remaining fourteen ORFs did not reveal any mutant phenotype in our basic growth tests.

[The course of the oropharyngeal stage of deglutition in physiological condition. Computer topokinetic analysis of videofluoroscopic images]. / Przebieg fazy gardlowej aktu polykania w warunkach fizjologicznych. Komputerowa analiza topokinetyczna obrazów rentgenokinematograficznych.

The performed analysis covers the physiology of the pharyngeal phase of deglutition in 11 patients aged 45-65 years. The studies were carried out with the aid of roentgenocinematographic examinations (RTGC) and after preparing an adequate computer program, a computer topokinetic analysis was accomplished (CTA). The measurement of parameters established in CTA make it possible to obtain the image of the pathway passed by the anatomical structures, the dynamics, the shape and the relative distances of two anatomical structures, with the duration of the deglutition act being taken into consideration. The use of RTGC images in CTA allows for better understanding of the mechanism acting in the pharyngeal phase of deglutition act in physiological conditions.

[Disorders of the pharyngeal stage of deglutition after classical and extended supraglottic laryngectomies. Computerized tomographic analysis of x-ray images]. / Zaburzenia fazy gardlowej aktu polykania po laryngektomiach nadglosniowych klasycznych i poszerzonych. Komputerowa analiza topokinetyczna obrazów rentgenokinematograficznych.

In 20 patients with laryngeal cancers, of both sexes and aged from 17 to 76 years, a partly classical or extended supraglottic laryngectomy was performed. The accomplished roentgenocinematographic analysis dealt with the disorders of the pharyngeal phase of deglutition act (RTGC). Next, by selecting characteristic schemas of frames for individual phases of deglutition, a computerized topokinetic analysis was carried out (CTA). The deglutition disorders were estimated in relation to the spared anatomical structures, formation of glosso-laryngeal recesses after this type of operations as well as leakage of contrast medium into the trachea.

The Saccharomyces cerevisiae ACR3 gene encodes a putative membrane protein involved in arsenite transport.

The cluster of three genes, ACR1, ACR2, and ACR3, previously was shown to confer arsenical resistance in Saccharomyces cerevisiae. The overexpression of ACR3 induced high level arsenite resistance. The presence of ACR3 together with ACR2 on a multicopy plasmid was conducive to increased arsenate resistance. The function of ACR3 gene has now been investigated. Amino acid sequence analysis of Acr3p showed that this hypothetical protein has hydrophobic character with 10 putative transmembrane spans and is probably located in yeast plasma membrane. We constructed the acr3 null mutation. The resulting disruptants were 5-fold more sensitive to arsenate and arsenite than wild-type cells. The acr3 disruptants showed wild-type sensitivity to antimony, tellurite, cadmium, and phenylarsine oxide. The mechanism of arsenical resistance was assayed by transport experiments using radioactive arsenite. We did not observe any significant differences in the accumulation of 76AsO33- in wild-type cells, acr1 and acr3 disruptants. However, the high dosage of ACR3 gene resulted in loss of arsenite uptake. These results suggest that arsenite resistance in yeast is mediated by an arsenite transporter (Acr3p).

Isolation of three contiguous genes, ACR1, ACR2 and ACR3, involved in resistance to arsenic compounds in the yeast Saccharomyces cerevisiae.

A 4.2 kb region from Saccharomyces cerevisiae chromosome XVI was isolated as a yeast fragment conferring resistance to 7 mM-sodium arsenite (NaAsO2), when put on a multicopy plasmid. Homology searches revealed a cluster of three new open reading frames named ACR1, ACR2 and ACR3. The hypothetical product of the ACR1 gene is similar to the transcriptional regulatory proteins, encoded by YAP1, and YAP2 genes from S. cerevisiae. Disruption of the ACR1 gene conduces to an arsenite and arsenate hypersensitivity phenotype. The ACR2 gene is indispensable for arsenate but not for arsenite resistance. The hypothetical product of the ACR3 gene shows high similarity to the hypothetical membrane protein encoded by Bacillus subtilis ORF1 of the skin element and weak similarity to the ArsB membrane protein of the Staphylococcus aureus arsenical-resistance operon. Overexpression of the ACR3 gene confers an arsenite- but not an arsenate-resistance phenotype. The presence of ACR3 together with ACR2 on a multicopy plasmid expands the resistance phenotype into arsenate. These findings suggest that all three novel genes: ACR1, ACR2 and ACR3 are involved in the arsenical-resistance phenomenon in S. cerevisiae.

Characterization of 8-(N-methylisopropyl)amino-N6-(5'-endohydroxy- endonorbornyl)-9-methyladenine (WRC-0571), a highly potent and selective, non-xanthine antagonist of A1 adenosine receptors.

Previous studies in our laboratory identified N6-endonorbornyl-9-methyladenine (N-0861) as a highly selective (100-fold) A1-adenosine receptor antagonist (KB = 500 nM). However, its moderate potency limits the degree of A1-receptor blockade that can be achieved by systemically administered N-0861. Structure activity studies were undertaken to invent a compound that had greater affinity for the A1-adenosine receptors than N-0861. C8-N-methylisopropylamino-N6-5'-endohydroxy-N-0861 (WRC-0571) inhibited [3H]-N6-cyclohexyladenosine (CHA) binding to guinea pig A1-receptors with a Ki value of 1.1 nM. WRC-0571 was 200-fold less potent at inhibiting [3H]-5'-N-ethylcarboxamidoadenosine binding to bovine A2a receptors (Ki = 234 nM). WRC-0571 also inhibited the binding of radioligands to cloned human A1, A2a and A3 adenosine receptors with affinities of 1.7, 105 and 7940 nM, respectively. Thus in human adenosine receptors, WRC-0571 is 62-fold selective for the A1 vs. A2a and 4670-fold selective for the A1 vs. A3 receptors; WRC-0571 is therefore the most A1 vs. A3 selective compound yet described. In guinea pig isolated atria, WRC-0571 antagonized the A1-mediated negative inotropic responses to 5'-N-ethylcarboxamidoadenosine (NECA) with a KB of 3.4 nM. WRC-0571 was more than 2500-fold less potent at antagonizing NECA-induced A2b-mediated relaxation in guinea pig aorta. In anesthetized rats WRC-0571 antagonized adenosine-induced bradycardia at concentrations as low as 1 nmol/kg but failed to antagonize A2-mediated hindquarter vasodilation at concentrations up to 10,000 nmol/kg. WRC-0571 is orally active at concentrations as low as 0.3 mumol/kg. WRC-0571 is therefore a highly potent, highly selective antagonist of A1-adenosine receptors both in vitro and in vivo.