An unusual foreign body obstructing endotracheal tube connector.
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Airway Obstruction↗
Biomedical subjects
B Roy
Publications and source records attributed to B Roy.
Deduced amino acid sequence of 2S storage protein from Brassica species and their conserved structural features.
2S seed storage albumin coding regions from five Brassica species, namely Brassica campestris, B. oleracea, B. nigra, B. juncea, and B. carinata have been cloned by PCR amplification of genomic DNA using oligonucleotide primers and their nucleotide sequences have been determined. These sequences showed more than 85% homology amongst themselves and considerable homology with some other crucifer 2S protein coding sequences. The deduced amino acid sequences showed more homology due to some inconsequential mutations in codons without changing the amino acids. Computer analysis of the protein sequences for possible secondary structure revealed a high degree of conservation of hydrophilic and hydrophobic domains and the invariant positions of cysteine residues. Unrooted phylogenic tree based on the coding region of 2S albumin from different Brassica species cloned by us and published sequences from other Cruciferae indicated that these genes originated before the evolutionary divergence of different Brassica species and were conserved due to some stringent structural and functional features required for seed metabolism.
Amino Acid Sequence↗
Activation function 2 (AF-2) of retinoic acid receptor and 9-cis retinoic acid receptor: presence of a conserved autonomous constitutive activating domain and influence of the nature of the response element on AF-2 activity.
A motif essential for the transcriptional activation function 2 (AF-2) present in the E region of retinoic acid receptor (RAR) alpha and 9-cis retinoic acid receptor (RXR) alpha has been characterized as an amphipathic alpha-helix whose main features are conserved between transcriptionally active members of the nuclear receptor superfamily. This conserved motif, which can activate autonomously in the absence of ligand in animal and yeast cells, can be swapped between nuclear receptors without affecting the ligand dependency for activation of transcription, thus indicating that a ligand-dependent conformational change is necessary to reveal the AF-2 activation potential within the E region of the nuclear receptor. Interestingly, we show that the precise nature of the direct repeat response element to which RAR/RXR heterodimers are bound can affect the activity of the AF-2s of the heterodimeric partners, as well as the relative efficiency with which all-trans and 9-cis retinoic acids activate the RAR partner.
Amino Acid Sequence↗
Erp61 is GRP58, a stress-inducible luminal endoplasmic reticulum protein, but is devoid of phosphatidylinositide-specific phospholipase C activity.
Using antibody raised against putative Form I phosphatidylinositide-specific phospholipase C (PI-PLC) and direct amino acid sequencing of the protein recognized by this antibody, we have shown that the antibody reacts with luminal endoplasmic reticulum (ER) proteins, including ERp61. ERp61 possesses a COOH-terminal QEDL sequence that acts as an ER retention signal. Additional experiments have shown, however, that PI-PLC activity is separable from ERp61 and that rat or murine ERp61 expressed in COS cells failed to produce an increase in PI-PLC activity in the COS cells. Finally, we have identified ERp61 as GRP58, a 58-kDa protein inducible by glycosylation block and treatment with the Ca2+ ionophore, A23187.
Amino Acid Sequence↗
Transactivation of the human p53 tumor suppressor gene by c-Myc/Max contributes to elevated mutant p53 expression in some tumors.
Elevated levels of mutant forms of the p53 tumor suppressor are a hallmark of many transformed cells. Multiple mechanisms such as increased stability of the protein and increased transcription of the gene can account for elevated p53 expression. Recent findings indicate that c-Myc/Max heterodimers can bind to an essential CA(C/T)GTG-containing site in the p53 promoter and elevate its expression. We have addressed the possibility that elevated mutant p53 expression is due to deregulated c-Myc expression. Here we demonstrate that the human p53 promoter is transactivated by high c-Myc expression and repressed by high Max expression. In examining the relative levels of c-Myc and p53 in human Burkitt's lymphomas and other B-lymphoid lines, we found that there is a correlation between the levels of c-Myc protein and p53 mRNA expression. In particular, cells that express very low levels of c-Myc protein also express low levels of p53 mRNA, while cells that express high levels of c-Myc tend to express high levels of p53 mRNA. To determine whether the p53 gene can be a target for c-Myc in vivo, we assayed the effects of antisense c-myc RNA on the levels of endogenous p53 mRNA. The results indicate that the presence of antisense c-myc RNA leads to a reduction in the levels of c-Myc protein, p53 mRNA, and expression from the p53 promoter. Taken together, our findings support a direct role for c-Myc in elevating expression of the mutant p53 gene in some tumors.
Animals↗
The glucose-regulated proteins (GRP78 and GRP94): functions, gene regulation, and applications.
The knowledge of GRPs as molecular chaperones is rapidly evolving. It is anticipated that the GRPs will make special contributions in the areas of basic cell biology, biotechnology, and cancer biology. In particular, they may play a role as the prototype of a class of genes that are regulated by signal transduction pathways originating in the ER and traveling to the nucleus. GRP78 and GRP94 function as molecular chaperones and can bind to malfolded proteins and unassembled complexes. They are induced in response to stress, but once the stress is removed the GRPs are posttranscriptionally modified into biologically inactive forms. The promoters of the grp genes are highly conserved, with several CCAAT-like motifs and GC-rich regions. The high level of redundancy that exists in the mammalian grp promoters may act to ensure that the expression of the genes, both of which are single copy, is unlikely to be significantly lowered in the event of mutation. These genes are thought to be controlled by several transcription factors whose complex interactions with the grp promoters allow variable patterns of grp induction. The promoters of the grp genes constitutively express their gene products, and their promoter activities can be further enhanced in cellular environments of low glucose or oxygen. The grp78 promoter is known to retain its strong activity in differentiated and undifferentiated tissues. These features make it an attractive alternative to viral promoters for use in gene therapy. Gene therapy may also be useful in treating cancer in some cases, especially solid tumors. In these instances, GRP levels are already likely to be quite high. These high levels of GRPs may inhibit the efficacy of several anti-cancer treatments. Suppression of GRP induction, perhaps by anti-sense or ribozyme technology, may prove to be useful in conjunction with anti-cancer drugs to treat tumors.
Animals↗
The Kansas Specific Health Plan.
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Cost-Benefit Analysis↗
Effect of drafting on heart rate in cross-country skiing.
The purpose of this study was to compare the heart rate responses during cross-country skiing as a leading skier, as well as in a drafting situation, 2 m behind the leader. Six male cross-country ski racers, paired for VO2max skied a 2-km course (two loops of 1 km) using the skating techniques at a fixed speed (5.6 m.s-1) on two different occasions, once as a leading skier, the other as a drafter. A recovery period of 30 min was allowed between the two trials. Heart rates (HR) were monitored every 5 s during all performances. Capillary blood lactate concentrations were taken before and at 5 min posttrial. Results revealed that HR were significantly lower (154 vs 163 beats.min-1) when skiing behind another skier as opposed to leading. Lactate concentrations were not significantly different between the two trials. Results also revealed that projected frontal areas appeared to influence the effects of drafting such that the HR differences between the leading and the drafting situations were larger for smaller skiers drafting behind larger skiers. These results showed that skiing behind another skier in a ski race would be very advantageous when the situation is encountered and that coaches should use the drafting situation in training so that athletes can practice this energy-saving strategy.
Adult↗
Biological inactivation of adhering Listeria monocytogenes by listeriaphages and a quaternary ammonium compound.
The use of listeriaphages as a means of disinfecting contaminated stainless-steel and polypropylene surfaces was investigated. Surfaces artificially contaminated with L. monocytogenes 10401 and 8427 were sanitized with suspensions of listeriaphages (H387, H387-A, and 2671), all belonging to the Siphoviridae family. Phage suspensions at concentrations of up to 3.5 x 10(8) PFU/ml were at least as efficient as a 20 ppm solution of a quaternary ammonium compound (QUATAL) in reducing L. monocytogenes populations. A synergistic activity was observed when two or more phages were used in combination and when phages were suspended in QUATAL. The biological activity of the three phages was not affected by QUATAL concentrations of 50 ppm and a contact time of 4 h.
Bacterial Adhesion↗
Rapid selection of donor myoblast clones for muscular dystrophy therapy using cell surface expression of NCAM.
This study describes an easy 3 step-procedure to prepare rapidly and at low cost, pure myoblast cell cultures from a normal muscle biopsy. Following collagenase and trypsin treatment of the tissue (step 1), dissociated cells were cloned at a density of 10 cells/ml in MCDB 120 medium (0.2 ml/well). Clones that grew were then tested for NCAM cell surface expression by cytofluorometric analysis (CFA) using Coulter CD56-PE monoclonal antibodies (step 2). Only those clones with more than 98% strongly labelled positive cells were expanded (step 3) for further trials in cell transfer therapy for dystrophic patients. Visualization of the pattern of NCAM expression was performed by immunoperoxidase assay, while the potential ability to form myotubes was confirmed by the observation of their formation within a period of 1 to 2 weeks. The 65% of the CD56+ clones in CFA were the same clones that proved to be myogenic with positive immunoperoxidase assay and myotube formation. This method avoids the fastidious and costly approach of cell sorting (whenever available), avoids contamination hazards due to many manipulations of the clones. Moreover this approach leads to a pure myoblast population free of any contaminating fibroblast which could contribute to connective tissue implement already deleterious in dystrophic patients.
Antibodies, Monoclonal↗
c-Myc trans-activates the p53 promoter through a required downstream CACGTG motif.
c-Myc and wild-type p53 have been shown to play important roles in the regulation of cellular proliferation and oncogenic transformation. We have previously shown that the p53 promoter contains a conserved consensus recognition sequence for the basic-helix-loop-helix-containing proteins, identical to the specific binding site for c-Myc/Max heterodimers. Here, we demonstrate that this element, which is required for full promoter activity, is bound by in vitro translated c-Myc/Max heterodimers. Furthermore, we found that in cotransfection assays, c-Myc trans-activates the p53 promoter as well as a hybrid herpes simplex virus-thymidine kinase promoter containing multiple copies of a synthetic p53-derived c-Myc binding site. The p53 promoter deleted of the basic-helix-loop-helix consensus recognition sequence is not trans-activated by c-Myc, thus suggesting that c-Myc trans-activates the p53 promoter through the basic-helix-loop-helix recognition motif. These findings raise the possibility that the p53 gene may be a potential target for trans-activation by c-Myc in vivo.
Animals↗
8-Azidoadenosine and ribonucleotide reductase.
Inhibitors of ribonucleotide reductase are potential antiproliferative agents, since they deplete cells from DNA precursors. Substrate nucleoside analogues, carrying azido groups at the base moiety, are shown to have strong cytostatic properties, as measured by the inhibition of the incorporation of thymidine into DNA. One compound, 8-azidoadenosine, inhibits CDP reduction in cytosolic extracts from cancer cells. The corresponding diphosphate behaves as a substrate for ribonucleotide reductase while the triphosphate is an allosteric effector.
Adenosine↗
Seasonal prevalence of some zoonotic trematode infections in cattle and pigs in the north-east montane zone in India.
Seasonal variations in the prevalence of Fasciola gigantica and Eurytrema pancreaticum in cattle, and Opisthorchis noverca, Artyfechinostomum malayanum, Fasciolopsis buski and Gastrodiscoides hominis in pigs, were studied post-necropsy over a 1 year period in a humid, subtropical north-east hilly region in India. The overall prevalence rate was 53.02% in cattle (n = 960) and 12.92% in pigs (n = 960). Fasciola gigantica and E. pancreaticum occurred throughout the year with peaks during cold winter months. Both species showed a high intensity of infection in winter and a low intensity during summer and autumn. The rate of infection due to A. malayanum, Fasciolopsis buski and G. hominis rose to a peak during June-September and thereafter declined to a low level (November-March). Except for the month of February, O. noverca occurred throughout the year, with the highest rate of infection in late autumn and winter. The abundance of infection due to A. malayanum, Fasciolopsis buski and G. hominis was high during late summer and early autumn. Opisthorchis noverca showed a higher density during late autumn and winter.
Animals↗
Production of manganic chelates by laccase from the lignin-degrading fungus Trametes (Coriolus) versicolor.
Many ligninolytic basidiomycete fungi have been shown to secrete a group of peroxidase isozymes whose sole function appears to be the peroxide-dependent oxidation of manganous [Mn(II)] to manganic [Mn(III)] ions. Manganic chelates and these Mn peroxidases have been implicated as central to the degradation of various natural and synthetic lignins and lignin-containing effluents by white rot (ligninolytic) fungi. Another group of enzymes, the laccases, are commonly secreted by wood-rotting fungi, but are generally regarded as being able to oxidize (and usually polymerize) only phenolic substrates. In this report it is shown that in the presence of appropriate oxidizable phenolic accessory substances or primary substrates, a variety of laccases and peroxidases catalyzing one-electron oxidations can also produce Mn(III) chelates from Mn(II).
Chelating Agents↗
Influence of dermal equivalent maturation on the development of a cultured skin equivalent.
Histologic and immunofluorescence methods were used to analyse the presence of fibronectin, chondroitin-4-sulphate and chondroitin-6-sulphate, type III and IV collagens, laminin, and keratins to assess the maturation level of cultured dermal and skin equivalents. In a first phase, fibroblasts in monolayer culture were compared with dermal equivalents in which fibroblasts are embedded in a type I collagen gel. Different fluorescent patterns were observed depending on the culture system used. A sequential appearance of macromolecules was noticed in dermal equivalents. Fibronectin was first detected after 4 days of culture, whereas chondroitin-4-sulphate and chondroitin-6-sulphate and type III collagen were present after 7 days. In contrast, all three macromolecules were detected at 24 h of culture in fibroblastic monolayer cultures. In a second phase, the quality of our skin equivalents was evaluated according to the seeding time of epidermal cells upon dermal equivalents (1, 4, or 7 days). A satisfactory stratification was obtained when keratinocytes were seeded after 4 and 7 days of dermal equivalent culture. Laminin and fibronectin were detected at the dermo-epidermal junction, but type IV collagen was absent. Various keratins, as detected by the AE1, AE2, and AE3 antibodies, were present in the epidermal layer. Following keratinocyte confluence, a change in the organization pattern of type III collagen in the dermal fraction of the skin equivalent was also noticed. Our comparative results show that seeding of epidermal cells on a more mature dermal equivalent leads to improved differentiation status of the epidermal layer.
Cell Division↗
Propulsive and gliding phases in four cross-country skiing techniques.
The purpose of this study was to compare the relative durations of the propulsive and gliding phases between three skating techniques (1-skate, 2-skate, and offset) and the diagonal stride technique in elite cross-country skiers. Nine skiers of provincial and national level were videotaped with a Panasonic AG 170 camera. The camera speed was set at 30 frames.s-1 and the shutter speed at 1/500 s. The athletes were asked to ski at approximately 80% of their maximal skiing speed on a flat (50 m long) and on an uphill course (35 m long, 5 degrees grade). The relative propulsive phases of the skating techniques were significantly longer than those of the diagonal stride. The relative gliding phases were also longer with the skating techniques. In addition, velocities obtained while skiing with the diagonal stride were about 16% slower than those attained with the skating techniques, principally related to the longer cycle lengths observed with the skating techniques, while cycle rates were quite similar between all four techniques. The results of this study suggest that the longer relative phases of propulsion with the skating techniques may explain the greater speed attained with these techniques in comparison with the diagonal stride.
Gait↗
Purification and properties of the low-molecular-weight alpha-crystallin from normal goat lens: comparison with bovine lens.
Low-molecular-weight alpha-crystallin (alpha L-crystallin) isolated from decapsulated lens of goat (Capra hiscus) has been purified to an apparently homogeneous population. Goat alpha L-crystallin closely resembles its bovine counterpart in size, shape, exposition of sulfhydryl groups, subunit composition and the nature of its UV-absorption profile. Like bovine alpha L-crystallin, dissociated subunits of goat alpha L-crystallin assemble upon reassociation into a particle of almost half the size of the native one. However, subunits of goat alpha L-crystallin are found to contain more aromatic amino acid residues than those of bovine subunits leading to a higher value of extinction coefficient (E1cm1%) at 280 nm for the goat protein.
Amino Acids↗
Human myoblast transplantation: a simple assay for tumorigenicity.
A simple assay for tumorigenicity of myoblasts to be transplanted to Duchenne patients has been developed. The assay is based on culture in a soft agar medium for 2-3 weeks. The tumor cell line forms large cell clusters while the normal myoblasts do not proliferate and remain isolated.
Cell Transformation, Neoplastic↗