CORRECTION OF COLLAPSED NASAL ALAE—A Simple Surgical Procedure

Collapse of the nasal alae against the septum brings about a serious obstruction to the airway. Collapse may be overlooked on routine examination because the speculum may prevent it.In most cases alar collapse can be corrected by a simple surgical procedure, herein described, which can be readily done at the same time as operation on the caudal portion of the septum.     

Correction of collapsed nasal alae; a simple surgical procedure

Collapse of the nasal alae against the septum brings about a serious obstruction to the airway. Collapse may be overlooked on routine examination because the speculum may prevent it. In most cases alar collapse can be corrected by a simple surgical procedure, herein described, which can be readily done at the same time as operation on the caudal portion of the septum.     

The Terminal Classic in the Maya Lowlands: Collapse, Transition, and Transformation

The Terminal Classic in the Maya Lowlands: Collapse, Transition, and Transformation. Arthur A. Demarest, Prudence M. Rice, and Don S. Rice, eds. Boulder: University Press of Colorado, 2004. 676 pp.     

Effects of ammonium concentration on Cs-137 fixation rate in soil suspensions

Collapse of interlayer spaces of soil clay minerals can by caused by ammonium cation in concentrations as low as 10(-3) mol/l. The collapse leads to substantial decrease in the soil ability to fix 137Cs. This effect is reversible and the soil fixation ability recovers after the ammonium concentration decrease.     

Changing U.S. Urban Neighborhoods: Patterns, Postmodern Analysis, and Policy Relevance

Left Behind in Rosedale: Race Relations and the Collapse of Community Institutions. Scott Cummings. Boulder, CO: Westview Press, 1998. 223 pp.
The Unknown City: The Lives of Poor and Working-Class Young Adults. Michelle Fine and Lois Weis. Boston, MA: Beacon Press, 1998. 328 pp.
The Anthropology of Lower Income Urban Enclaves: The Case of East Harlem. Judith Freidenberg. ed. New York: New York Academy of Sciences, 1995. 286 pp.     

Disruption of the cytoskeleton during Semaphorin 3A induced growth cone collapse correlates with differences in actin organization and associated binding proteins

Repulsive guidance cues induce growth cone collapse or collapse and retraction. Collapse results from disruption and loss of the actin cytoskeleton. Actin‐rich regions of growth cones contain binding proteins that influence filament organization, such as Arp2/3, cortactin, and fascin, but little is known about the role that these proteins play in collapse. Here, we show that Semaphorin 3A (Sema 3A), which is repulsive to mouse dorsal root ganglion neurons, has unequal effects on actin binding proteins and their associated filaments. The immunofluorescence staining intensity of Arp‐2 and cortactin decreases relative to total protein; whereas in unextracted growth cones fascin increases. Fascin and myosin IIB staining redistribute and show increased overlap. The degree of actin filament loss during collapse correlates with filament superstructures detected by rotary shadow electron microscopy. Collapse results in the loss of branched f‐actin meshworks, while actin bundles are partially retained to varying degrees. Taken together with the known affects of Sema 3A on actin, this suggests a model for collapse that follows a sequence; depolymerization of actin meshworks followed by partial depolymerization of fascin associated actin bundles and their movement to the neurite to complete collapse. The relocated fascin associated actin bundles may provide the substrate for actomyosin contractions that produce retraction. © 2009 Wiley Periodicals, Inc. Develop Neurobiol 2009     

Dorsal Root Ganglion Neurons React to Semaphorin 3A Application through a Biphasic Response that Requires Multiple Myosin II Isoforms

Growth cone responses to guidance cues provide the basis for neuronal pathfinding. Although many cues have been identified, less is known about how signals are translated into the cytoskeletal rearrangements that steer directional changes during pathfinding. Here we show that the response of dorsal root ganglion (DRG) neurons to Semaphorin 3A gradients can be divided into two steps: growth cone collapse and retraction. Collapse is inhibited by overexpression of myosin IIA or growth on high substrate-bound laminin-1. Inhibition of collapse also prevents retractions; however collapse can occur without retraction. Inhibition of myosin II activity with blebbistatin or by using neurons from myosin IIB knockouts inhibits retraction. Collapse is associated with movement of myosin IIA from the growth cone to the neurite. Myosin IIB redistributes from a broad distribution to the rear of the growth cone and neck of the connecting neurite. High substrate-bound laminin-1 prevents or reverses these changes. This suggests a model for the Sema 3A response that involves loss of growth cone myosin IIA to facilitate actin meshwork instability and collapse, followed by myosin IIB concentration at the rear of the cone and neck region where it associates with actin bundles to drive retraction.     

Backbone-driven collapse in unfolded protein chains

Collapse of unfolded protein chains is an early event in folding. It affects structural properties of intrinsically disordered proteins, which take a considerable fraction of the human proteome. Collapse is generally believed to be driven by hydrophobic forces imposed by the presence of nonpolar amino acid side chains. Contributions from backbone hydrogen bonds to protein folding and stability, however, are controversial. To date, the experimental dissection of side-chain and backbone contributions has not yet been achieved because both types of interactions are integral parts of protein structure. Here, we realized this goal by applying mutagenesis and chemical modification on a set of disordered peptides and proteins. We measured the protein dimensions and kinetics of intra-chain diffusion of modified polypeptides at the level of individual molecules using fluorescence correlation spectroscopy, thereby avoiding artifacts commonly caused by aggregation of unfolded protein material in bulk. We found no contributions from side chains to collapse but, instead, identified backbone interactions as a source sufficient to form globules of native-like dimensions. The presence of backbone hydrogen bonds decreased polypeptide water solubility dramatically and accelerated the nanosecond kinetics of loop closure, in agreement with recent predictions from computer simulation. The presence of side chains, instead, slowed loop closure and modulated the dimensions of intrinsically disordered domains. It appeared that the transient formation of backbone interactions facilitates the diffusive search for productive conformations at the early stage of folding and within intrinsically disordered proteins.     

Predicting the location of the non-local contacts in α-synuclein

In this paper, the Sequential Collapse Model (SCM) for protein folding pathways is applied to investigate the location of the non-local contacts in the intrinsically disordered state of α-synuclein, a protein implicated in the onset and spreading of several serious neurodegenerative diseases. The model relies on the entropic cost of forming protein loops due to self-crowding effects, and the protein sequence to determine contact location and stability. It is found that the model predicts the existence of several possible non-local contacts, and the location of the non-local contacts is consistent with existing experimental evidence. The bearing of these findings on the pathogenic mechanism and its regulation is discussed.     

Generation of the electrochemical potential of Na+ by the Na+-motive NADH oxidase in inverted membrane vesicles of Vibrio alginolyticus

Inverted membrane vesicles prepared from Vibrio alginolyticus generated a membrane potential (positive inside) and accumulated Na+ by the oxidation of NADH. Generation of the membrane potential required Na+ and was inhibited by 2-heptyl-4-hydroxyquinoline N-oxide, a specific inhibitor of the Na+-dependent NADH oxidase. Collapse of the membrane potential by valinomycin stimulated the uptake of Na+. In contrast, accumulation of H+ was not detected under all the conditions tested. These results suggest that only Na+ is translocated by the Na+-dependent NADH oxidase of V. alginolyticus.     

The Present-Day Usage of Pneumothorax in the Treatment of Pulmonary Tuberculosis

The patient with tuberculosis must heal himself. Collapse measures help in the healing process by making the environment of the tubercle bacilli in the lungs more intolerant of multiplication and spread. The usage of pneumothorax has decreased; ten years ago it was used for over 50 per cent of patients, now for less than 10 per cent. This reduction in usage is not a condemnation of the procedure but an index of the more judicious application of the treatment as adjuvant to other accepted forms of therapy. Pneumothorax, because it is so versatile and flexible, lends itself most effectively to combination with other collapse procedures. Its use for well selected purposes is still indicated, but in much more narrow limits than previously applied.     

蜂群衰竭失调病(CCD)致病因子分析及我国的应对措施

2006年冬到2007年春,"蜂群衰竭失调"(简称CCD)病席卷了美国等世界上许多国家,造成这些国家蜂群数量锐减并引发严重的农作物授粉危机。为了尽快控制病情,CCD研究小组展开大范围的调查和研究。结果表明病原体、杀虫剂、转基因作物及气候暖化等都可能是蜂群衰竭失调的原因之一;最新研究显示,以色列急性麻痹病病毒很可能是主要的致病因子,但最终病因仍未确定。文章综述国外CCD研究进展,并论述我国相应的应对措施。     

Isolation from chick somites of a glycoprotein fraction that causes collapse of dorsal root ganglion growth cones

The segmented pattern of peripheral spinal nerves in higher vertebrates is generated by interactions between nerve cells and somites. Neural crest cells, motor axons, and sensory axons grow exclusively through anterior-half sclerotome. In chick embryos, posterior cells bind the lectins peanut agglutinin (PNA) and Jacalin. When liposomes containing somite extracts are applied to cultures of chick sensory neurons, growth cones collapse abruptly, recovering within 4 hr of liposome removal. Collapse activity is eliminated by immobilized PNA, and SDS-PAGE demonstrates two major components (48K and 55K), which are absent from anterior-half sclerotome. Rabbit polyclonal antibodies against these components recognize only posterior cells and may also be used to eliminate collapse activity. We suggest that spinal nerve segmentation is produced by inhibitory interactions between these components and growth cones.     

Detection of honey bee (Apis mellifera) viruses with an oligonucleotide microarray

In recent years, declines in honey bee (Apis mellifera L.) colonies have been observed to varying degrees worldwide with the worst losses in the USA being termed Colony Collapse Disorder (CCD). Pathogen load and the prevalence of honey bee viruses have been implicated in these losses and many diseased hives have multiple viruses present. We have designed and tested an oligonucleotide microarray which enables the simultaneous detection of nine honey bee viruses: Acute bee paralysis virus, Black queen cell virus, Chronic bee paralysis virus, Deformed wing virus, Kashmir bee virus, Sacbrood virus, Israel acute paralysis virus, Varroa destructor virus 1 and Slow paralysis virus. The microarray can be used to robustly diagnose nine viruses in one test.     

Dynamic morphology of calcium-induced interactions between phosphatidylserine vesicles.

Structural changes in phosphatidylserine vesicles exposed to calcium chloride for various times have been observed by means of video-enhanced light microscopy and freeze-fracture electron microscopy. Large flat double-bilayer diaphragms form at the contacts between aggregated vesicles within milliseconds. Bilayers at and outside of diaphragms rupture and allow vesicles to collapse completely by flattening against each other within seconds. Collapse through intermediate states to a stable multilamellar phase is complete within minutes. The Ca-induced attraction energy and the resultant flattening at contacts between vesicles is far beyond that needed to stress bilayers to the point of rupture. Although the destabilizing response to this stress is preferential to the diaphragm region, 40% of adhering pairs rupture outside of the diaphragm region rather than fuse with each other. In this respect the mechanism of fusion between these vesicles may be fundamentally different from the controlled fusion process in cells.     

Isolation of a gene for a regulatory 15-kDa subunit of mitochondrial F1F0-ATPase and construction of mutant yeast lacking the protein

A gene coding for yeast 15-kDa protein, a regulatory factor of mitochondrial F1F0-ATPase, was isolated. The cloned gene was disrupted in vitro and mutant strains that did not contain the 15-kDa protein were constructed by transformation of yeast cells with the disrupted gene. The ATP-synthesizing activity of the mutant mitochondria was the same as that of wild-type cells, suggesting that the 15-kDa protein is not required for mitochondrial oxidative phosphorylation. Collapse of the membrane potential induced ATP-hydrolyzing activity of F1F0-ATPase of the mutant mitochondria but not of normal mitochondria. Activation of the enzyme was also observed during incubation of submitochondrial particles from mutant cells, but not of those from wild-type cells. Thus, it is inferred that the 15-kDa protein supports the action of an intrinsic ATPase inhibitor of the ATP-hydrolyzing activity of the enzyme upon de-energization of mitochondrial membranes.     

Fast folding of a prototypic polypeptide: the immunoglobulin binding domain of streptococcal protein G.

The folding of the small (56 residues) highly stable B1 immunoglobulin binding domain (GB1) of streptococcal protein G has been investigated by quenched-flow deuterium-hydrogen exchange. This system represents a paradigm for the study of protein folding because it exhibits no complicating features superimposed upon the intrinsic properties of the polypeptide chain. Collapse to a semicompact state exhibiting partial order, reflected in protection factors for ND-NH exchange up to 10-fold higher than that expected for a random coil, occurs within the dead time (< or = 1 ms) of the quenched flow apparatus. This is followed by the formation of the fully native state, as monitored by the fractional proton occupancy of 26 backbone amide groups spread throughout the protein, in a single rapid concerted step with a half-life of 5.2 ms at 5 degrees C.     

The Basic Principles of Collapse Therapy

Collapse therapy has a definite objective of resting and healing tuberculous lesions. It should be used, not so much as an independent means, but as a supplement to other established practices in the treatment of tuberculosis.The indications for each measure have changed over the years and are still changing, so that proper treatment can be given only by those having a knowledge of the changing trends, as well as of the disease and principles of treatment. Each case should be handled on its merits and the choice of procedure should depend generally upon the circumstances, such as the skill of the physician carrying it out, the facilities for the care of the patient, and the equipment for working. Above all, it should be recognized that knowledge, experience, and especially wisdom will go far towards achieving good results.     

Numerical simulation of noninvasive blood pressure measurement

In this paper, a simulation model based on the partially pressurized collapsible tube model for reproducing noninvasive blood pressure measurement is presented. The model consists of a collapsible tube, which models the pressurized part of the artery, rigid pipes connected to the collapsible tube, which model proximal and distal region far from the pressurized part, and the Windkessel model, which represents the capacitance and the resistance of the distal part of the circulation. The blood flow is simplified to a one-dimensional system. Collapse and expansion of the tube is represented by the change in the cross-sectional area of the tube considering the force balance acting on the tube membrane in the direction normal to the tube axis. They are solved using the Runge-Kutta method. This simple model can easily reproduce the oscillation of inner fluid and corresponding tube collapse typical for the Korotkoff sounds generated by the cuff pressure. The numerical result is compared with the experiment and shows good agreement.     

Non-Specific dsRNA-Mediated Antiviral Response in the Honey Bee

Honey bees are essential pollinators of numerous agricultural crops. Since 2006, honey bee populations have suffered considerable annual losses that are partially attributed to Colony Collapse Disorder (CCD). CCD is an unexplained phenomenon that correlates with elevated incidence of pathogens, including RNA viruses. Honey bees are eusocial insects that live in colonies of genetically related individuals that work in concert to gather and store nutrients. Their social organization provides numerous benefits, but also facilitates pathogen transmission between individuals. To investigate honey bee antiviral defense mechanisms, we developed an RNA virus infection model and discovered that administration of dsRNA, regardless of sequence, reduced virus infection. Our results suggest that dsRNA, a viral pathogen associated molecular pattern (PAMP), triggers an antiviral response that controls virus infection in honey bees.