Nasal air temperature and airflow during respiration in numerical simulation based on multislice computed tomography scan.

Background: Adequate nasal air-conditioning is of greatest importance. Because detailed processes of nasal air-conditioning still are not completely understood, numerical simulations of intranasal temperature distribution and airflow patterns during inspiration and expiration were performed.

Methods: A three-dimensional model of the human nose based on computed tomography scans was reconstructed.

Persistence of zinc-binding bacterial superantigens at the surface of antigen-presenting cells contributes to the extreme potency of these superantigens as T-cell activators.

Bacterial superantigen intoxication causes massive overactivation of T cells, which can result in potentially lethal toxic shock. Superantigens fall into two groups: superantigens such as staphylococcal enterotoxin B (SEB) that contain a single generic binding site for major histocompatibility complex class II (MHC-II) and more potent superantigens such as SEA with a second, zinc-dependent MHC-II binding site that enables them to cross-link adjacent MHC-II molecules. We found that although all superantigens bound rapidly to the surface of human B cells, zinc-binding superantigens largely remained at the cell surface for at least 40 h.

Numerical simulation of airflow patterns and air temperature distribution during inspiration in a nose model with septal perforation.

Background: The most typical symptoms of patients with nasal septal perforation (SP) are crusting and recurrent nosebleed. The objective of the study was to determine the influence of SP on intranasal temperature profile and airflow patterns during inspiration by means of numerical simulation.

Methods: Two realistic bilateral models of the human nose with and without SP were reconstructed based on computed tomography (CT).

Numerical simulation of air temperature and airflow patterns in the human nose during expiration.

Recovery of heat and water during expiration is an important but not yet fully understood function of the nose. The presented study investigated cooling of the expiratory air for heat recovery within the human nose applying numerical simulation. A numerical simulation in a bilateral three-dimensional model of the human nose based on computed tomography was employed.

A numerical simulation of intranasal air temperature during inspiration.

Objectives/hypothesis: In vivo measurements of the intranasal air temperature are feasible. The present study was designed to reproduce temperature distributions within the human nasal cavity by means of numerical simulation.

Study Design: Numerical simulation.

[Non-invasive, multi detector row (MDR) CT based computational fluid dynamics (CFD) analysis of hemodynamics in infrarenal abdominal aortic aneurysm (AAA) before and after endovascular repair].

Purpose: Simulation, description and analysis of dynamic pressure in infrarenal abdominal aortic aneurysms (AAA) before and after endovascular repair.

Materials And Methods: During March 1996 and May 2001, 13 patients with AAA underwent endovascular treatment. The MDR-CT scans of these patients were used for the non-invasive analysis of the hemodynamics in the aorta with CFD software before and after endovascular repair.

Latent phenoloxidase activity and N-terminal amino acid sequence of hemocyanin from Bathynomus giganteus, a primitive crustacean.

N-terminal amino acid sequences for the two hemocyanin subunits from the deep-sea crustacean Bathynomus giganteus have been determined by Edman degradation, providing the first sequence information for a hemocyanin from an isopod. In addition, purified hemocyanin from B. giganteus exhibited phenoloxidase activity in the presence of sodium dodecyl sulfate.

[Precision in standardized Iso-C-Arm based navigated boring of the proximal femur].

C-arm navigation is a new tool in computer assisted surgery. The aim of this study is to evaluate the accuracy of Iso-C-arm based drill holes in the proximal femur. In nine artificial proximal femura, two holes with an angle of 135 degrees and 100 degrees in relation to the shaft axis were drilled in the direction of the femoral head.

High-affinity, protective antibodies to the binding domain of botulinum neurotoxin type A.

Monoclonal antibodies (MAbs) were prepared against the putative binding domain of botulinum neurotoxin A (BoNT/A), a nontoxic 50-kDa fragment. Initially, all fusion products were screened against the holotoxin BoNT/A and against the binding fragment, BoNT/A H(C). Eleven neutralizing hybridomas were cloned, and their specific binding to BoNT/A H(C) was demonstrated by surface plasmon resonance, with dissociation constants ranging from 0.

Characterization of the UDP-glucuronosyltransferases involved in the glucuronidation of an antithrombotic thioxyloside in rat and humans.

To investigate the glucuronidation on the hydroxyl group of carbohydrate-containing drugs, the in vitro formation of glucuronides on the thioxyloside ring of the antithrombotic drug, LF 4.0212, was followed in rat and human liver microsomes and with recombinant UDP-glucuronosyltransferases (UGT). The reaction revealed a marked regioselectivity in rat and humans.

Identifying the principal protective antigenic determinants of type A botulinum neurotoxin.

The neurotoxins from Clostridium botulinum (BoNT serotypes A-G) exert their lethal effect by preventing the release of acetylcholine at the neuromuscular junction. As with tetanus toxin, immunization with a non-toxic fragment, the 50 kDa C-terminal portion of BoNT/A (Hc; residues 861-1296), protects mice against lethal challenges with the intact toxin. To locate the neutralizing epitopes, several protective monoclonal antibodies (mAbs) against BoNT/A-Hc were isolated and cloned.

Arginine 52 and histidine 54 located in a conserved amino-terminal hydrophobic region (LX2-R52-G-H54-X3-V-L) are important amino acids for the functional and structural integrity of the human liver UDP-glucuronosyltransferase UGT1*6.

The hepatic UDP-glucuronosyltransferase UGT1*6 is actively involved in the glucuronidation of short and planar phenols in humans. Based on the irreversible inhibition of the enzyme on chemical modification by 2,3-butanedione and diethyl pyrocarbonate, the roles of His54 and Arg52 were investigated by oligonucleotide site-directed mutagenesis. These amino acids belong to a consensus sequence LX2-R52-G-H54-X3-V-L located in a conserved hydrophobic region of the variable amino-terminal domain of UGT.

In vitro fusion of endocytic vesicles: effects of reagents that alter endosomal pH.

Ricin, a plant toxin that binds to galactose-terminated glycoproteins and glycolipids on the cell surface, is internalized into endosomes before reaching the cytosol where it exerts its toxic activity. Fusion of early endosomes containing ricin or transferrin was demonstrated by using postnuclear supernatant fractions from K-562 cells. For both ligands, fusion depended on time, temperature, and ATP and was blocked by preincubation with N-ethylmaleimide.

Characterization of 3'-azido-3'-deoxythymidine inhibition of ricin and Pseudomonas exotoxin A toxicity in CHO and Vero cells.

Ricin (RIC), modeccin (MOD), Pseudomonas exotoxin A (PE), and diphtheria toxin (DT) are protein toxins that enter cells by receptor-mediated endocytosis. After intracellular transport and membrane translocation to the cytosol, these toxins inhibit protein synthesis by enzymatically removing a specific adenine residue from ribosomal RNA (RIC, MOD), or by ADP-ribosylation of elongation factor-2 (PE, DT). Recently, Thompson and Pace (1992) reported that AZT (3'-azido-3'-deoxythymidine) inhibited RIC toxicity in Vero cells, and this inhibition was not due to a block of RIC enzymatic activity.

Enzymatic conversion of proteins to glycoproteins.

The enzymatic transfer of the oligosaccharide moiety from an oligosaccharide-lipid to denatured forms of three secretory proteins--ovalbumin, alpha-lactalbumin, and ribonuclease A--has been demonstrated utilizing a membrane fraction from hen oviduct. Based on a survey of 10 proteins denatured by sulfitolysis, the presence of the tripeptide sequence -Asn-X-Thr-Ser- (X represents a variable amino acid) appears to be necessary but not sufficient for the protein to serve as acceptor in vitro. The results of this investigation also suggest that unfolding of the polypeptide chain is required in order to expose sites for carbohydrate attachment.

A lipid-linked oligosaccharide intermediate in glycoprotein synthesis. Characterization of [Man-14C]glycoproteins labeled from [Man-14C]oligosaccharide-lipid and GDP-[14C]Man.

Endogenous proteins of cell-free preparations of hen oviduct labeled from GDP-[14C]Man or from [Man-14C]oligosaccharide-lipid have been compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Under the conditions tested, a polypeptide chain of molecular weight about 25,000 was the principle acceptor for the oligosaccharide moiety of exogenous [Man-14C]oligosaccharide-lipid. The product labeled by [Man-14C]oligosaccharide-lipid appeared identical with one of three glycoproteins formed when GDP-[14C]Man was incubated with a crude membrane fraction.

The characterization of mannan of Micrococcus lysodeikticus as an acidic lipopolysaccharide.

Ghosts of Micrococcus lysodeikticus contain a mannan that is not removed by intensive washing procedures. Purified mannan, isolated by extraction of whole cells with hot, aqueous phenol, binds to membranes in vitro. Mannan also binds to DEAE-cellulose and migrates toward the anode in neutral and sodium dodecyl sulfate disc gel electrophoresis.