Lectin binding by macroglial and microglial cells in the brains of young normal and myelin-deficient (md) mutant rats

To distinguish macroglia (oligodendrocytes and astrocytes) frommicroglia in the brain, ‘markers’ that have beenused in previous studies include carbonic anhydrase II (CAII)immunoreactivity for macroglia, and Ricinusand Bandeiraea(BS-I)lectins for microglia. However, in rats <1 week of age, manycells stained intensely with both anti-CAII and the labelledBS-I lectin. If some of the BS-I+/CAII+ cells were macroglia,and not microglia, BS-I should no longer be regarded as specificfor microglia. To confirm or rule out that possibility, lectinhistochemistry and double immunofluorescence staining were performedin tissue from the brains of normal young rats and from themicroglial cell-enriched brains of myelin-deficient mutant rats.BS-I+/ CAII+ cells were found and examined. The BS-I +/CAII-cellsresembled macrophages and microglia and did, indeed, differin sizes and shapes from the BS-I+/+cells. The BS-I+/CAII+ cellsappeared to represent CAII+ putative oligodendrocyte precursorsdescribed previously. Although less obvious, a lectin-bindingstructure was also observed in astrocytes. Lectins may cross-reactwith macroglial glycoproteins. For example, a glycoprotein foundin o ligodendrocytes and myelin, the myelin-associated glycoprotein(MAG), is related to the Ig superfamily and cell adhesion molecules.Therefore, it is cautioned that lectins and antibodies againstmembers of the latter families of proteins should be used ascell-type specific markers only if other parameters are alsoexamined. astrocytes carbonic anhydrase lectins microglia oligodendrocytes     

Lipid class analysis of the central nervous system of myelin-deficient Wistar rats

Brains and spinal cords of myelin-deficient (md) and littermate control rats were analyzed serially for myelin lipids during the period from 13 to 32 days of age. The glycolipids of md rat brains were severely reduced and remained so during the period of study; brain cholesterol and phospholipids increased moderately but never reached the values for control brains. Deficiency of all three lipid classes was marked in the spinal cord and did not change with age. Among the glycolipids of md rats, deficiency was more severe in cerebrosides than sulfatides. The pronounced reduction of cerebrosides in the early stages of myelination suggests that abnormal synthesis of these glycolipids may be the most important biochemical anomaly responsible for myelin deficiency.--Csiza, C.K. Lipid class analysis of the central nervous system of myelin-deficient Wistar rats.     

Molecular dynamics (MD) in homocysteine nanosystems - computer simulation

Excessive of homocysteine in the human body is recently considered as a factor increasing the risk of the cardiovascular system diseases. The nanosystem composed of finite number of homocysteine molecules (n=20, 50 and 80) have been studied by MD technique. Several physical quantities of homocysteine nanosystem have been calculated as a function of temperature and a number of molecules in homocysteine cluster. The total dipole moment autocorrelation function and dielectric loss of the cluster have been also obtained.     

Myelin instability and oligodendrocyte metabolism in myelin-deficient mutant mice

During the active phase of myelination in myelin-deficient mutant mice (mld), myelin basic protein (MBP) synthesis is defective and the myelin lamellae are uncompacted. In these mutants, we found a fast metabolism of the myelin-associated glycoprotein (MAG) and of sulfatides, and the presence of cholesterol esters and a degradation product of MAG, dMAG, indicating that mld myelin was unstable. The increased synthesis of MAG and Wolfgram protein, two proteins present in uncompacted myelin sheath and paranodal loops, was demonstrated by high levels of messengers. Simultaneously, we found an accumulation of inclusion bodies, vacuoles, and rough endoplasmic reticulum in mld oligodendrocytes. This material was heavily immunostained for MAG. Furthermore, the developmental change between the two molecular forms of MAG (p72MAG/p67MAG) was delayed in mld mice. In 85-d-old mld mice, the MBP content increased and myelin lamellae became better compacted. In these mutants, dMAG was absent and MAG mRNAs were found in normal amounts. Furthermore, the fine structure of mld oligodendrocytes was normal and the MAG immunostaining was similar to age-matched controls. These results support a functional role for MBP in maintaining the metabolic stability and the compact structure of myelin. Furthermore, in the absence of MBP and myelin compaction, the regulation of the synthesis of at least two membrane proteins related to myelin cannot proceed.     

Molecular dynamics (MD) simulations of VIP and PACAP27

Vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase‐activating polypeptide‐27 (PACAP27) are members of the secretin‐glucagon family containing 28 and 27 residues, respectively. NMR spectroscopy studies suggest that the N‐terminus exhibit consecutive β‐turns whereas the central and C‐terminal parts of the VIP molecule have been characterized as being two α‐helices. In contrast, similar studies carried out on PACAP suggest that the shortest active peptide segment PACAP27 in the presence of trifluoroethanol (TFE) exhibits a disordered N‐terminal domain followed by a α‐helix expanding residues 9–26 with a discontinuity between residues 20 and 21. In the present study, a series of MD trajectories of VIP and PACAP27 were carried out using two different implicit models of the solvent: the Generalized Born that use an effective Born radii described by Onufriev, Bashford, and Case (GB^OBC) and the Hawkins, Cramer, and Truhlar approximation (GB^HCT) and two different force fields: AMBER ff99 and a modified version of the latter described by Sorin and Pande (Biophys J 2005, 88, 2472‐2493), ff99SP. Comparison of the structures obtained from the MD trajectories and those derived from the NMR studies in the literature indicates that the GB^OBC method is more efficient in the exploration of the conformational space and presents a higher agreement with the experimental structure of VIP and PACAP27 in TFE. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 391–400, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com     

Water transport in human aquaporin-4: molecular dynamics (MD) simulations

Aquaporin-4 (AQP4) is the predominant water channel in the central nervous system, where it has been reported to be involved in many pathophysiological roles including water transport. In this paper, the AQP4 tetramer was modeled from its PDB structure file, embedded in a palmitoyl-oleoyl-phosphatidyl-choline (POPC) lipid bilayer, solvated in water, then minimized and equilibrated by means of molecular dynamics simulations. Analysis of the equilibrated structure showed that the central pore along the fourfold axis of the tetramers is formed with hydrophobic amino acid residues. In particular, Phe-195, Leu-191 and Leu-75, form the narrowest part of the pore. Therefore water molecules are not expected to transport through the central pore, which was confirmed by MD simulations. Each monomer of the AQP4 tetramers forms a channel whose walls consist mostly of hydrophilic residues. There are eight water molecules in single file observed in each of the four channels, transporting through the selectivity filter containing Arg-216, His-201, Phe-77, Ala-210, and the two conserved Asn-Pro-Ala (NPA) motifs containing Asn-213 and Asn-97. By using Brownian dynamics fluctuation–dissipation-theorem (BD-FDT), the overall free-energy profile was obtained for water transporting through AQP4 for the first time, which gives a complete map of the entire channel of water permeation.     

One-Sided Tests in Clinical Trials with Multiple Endpoints

Treatment comparisons in clinical trials often involve several endpoints. For example, one might wish to demonstrate that a new treatment is superior to the current standard for some components of the multivariate response vector and is not inferior, modulo biologically unimportant difference to the standard treatment for all other components. We introduce a new approach to multiple-endpoint testing that incorporates the essential univariate and multivariate features of the treatment effects. This approach is compared with existing methods in a simulation study and applied to data on rheumatoid arthritis patients receiving one of two treatments.     

Micropropagation of a recalcitrant male asparagus clone (MD 22-8)

TheAsparagus officinalis male asparagus clone MD 22–8 (Howard Scott) is highly prized by asparagus breeders but has been very difficult to micropropagate due to its slow growth rate and reluctance to initiate roots. Shoot tips cultured on indole-3-acetic acid or indole-3-propionic acid, at concentrations of 1.53 and 1.44 M respectively, resulted in levels of root initiation and elongation equal to or better than those of a female asparagus clone. These culture conditions also improved the rates of shoot initiation and elongation. Root initiation and elongation were further increased by culture conditions that provided enhanced gas exchange.Abbreviations BA 6-benzyladenine - IAA 3-indoleacetic acid - IPA indolepropionic acid - NAA -naphthaleneacetic acid - 2,4-d 2,4-dichlorophenoxyacetic acid - 2,4,5-T 2,4,5-trichlorophenox-yacetic acid - PPF photosynthetic photon flux - MS Murashige & Skoog     

Alterations in the accumulation patterns of polyamines in brains of myelin-deficient mice

Quaking mutants and jimpy mutants of mice have known deficiencies of myelination of the central nervous system, as well as lesser involvement of the peripheral nervous system. Both mutants also have altered polyamine synthesis and accumulation, particularly in the hindbrain and spinal column. The ratio of spermidine/spermine, which generally is higher in tissues with high rates of biosynthetic activity, was significantly lower in the mutants as compared to their normal siblings. In quaking mutants, 5 months of age, the spermidine concentration of hindbrain and spinal column was 60% that of controls. In contrast, the decreased spermidine/spermine ratio in jimpy mutants resulted from a marked increase in the spermine concentration in both forebrain and hindbrain. Alterations in the spermidine/spermine ratio could lead to reductions in the biosynthetic potential of the brain during development.     

Transmission Assessment Surveys (TAS) to Define Endpoints for Lymphatic Filariasis Mass Drug Administration: A Multicenter Evaluation

Background

Lymphatic filariasis (LF) is targeted for global elimination through treatment of entire at-risk populations with repeated annual mass drug administration (MDA). Essential for program success is defining and confirming the appropriate endpoint for MDA when transmission is presumed to have reached a level low enough that it cannot be sustained even in the absence of drug intervention. Guidelines advanced by WHO call for a transmission assessment survey (TAS) to determine if MDA can be stopped within an LF evaluation unit (EU) after at least five effective rounds of annual treatment. To test the value and practicality of these guidelines, a multicenter operational research trial was undertaken in 11 countries covering various geographic and epidemiological settings.

Methodology

The TAS was conducted twice in each EU with TAS-1 and TAS-2 approximately 24 months apart. Lot quality assurance sampling (LQAS) formed the basis of the TAS survey design but specific EU characteristics defined the survey site (school or community), eligible population (6–7 year olds or 1^st–2^nd graders), survey type (systematic or cluster-sampling), target sample size, and critical cutoff (a statistically powered threshold below which transmission is expected to be no longer sustainable). The primary diagnostic tools were the immunochromatographic (ICT) test for W. bancrofti EUs and the BmR1 test (Brugia Rapid or PanLF) for Brugia spp. EUs.

Principal Findings/Conclusions

In 10 of 11 EUs, the number of TAS-1 positive cases was below the critical cutoff, indicating that MDA could be stopped. The same results were found in the follow-up TAS-2, therefore, confirming the previous decision outcome. Sample sizes were highly sex and age-representative and closely matched the target value after factoring in estimates of non-participation. The TAS was determined to be a practical and effective evaluation tool for stopping MDA although its validity for longer-term post-MDA surveillance requires further investigation.     

A comparison between two prokaryotic potassium channels (KirBac1.1 and KcsA) in a molecular dynamics (MD) simulation study

The two potassium ion channels KirBac1.1 and KcsA are compared in a Molecular Dynamics (MD) simulation study. The location and motion of the potassium ions observed in the simulations are compared to those in the X-ray structures and previous simulations. In our simulations several of the crystallography resolved ion sites in KirBac1.1 are occupied by ions. In addition to this, two in KirBac1.1 unresolved sites where occupied by ions at sites that are in close correspondence to sites found in KcsA. There is every reason to believe that the conserved alignment of the selectivity filter in the potassium ion channel family corresponds to a very similar mechanism for ion transport across the filter. The gate residues, Phe146 in KirBac1.1 and Ala111 in KcsA acted in the simulations as effective barriers which never were passed by ions nor water molecules.     

Expanded Damage Function of Stratospheric Ozone Depletion to Cover Major Endpoints Regarding Life Cycle Impact Assessment (12 pp)

Background Stratospheric ozone depletion is one of the important environmental issues for LCIA. The National LCA Project of Japan has developed a framework of LCIA since 1998, which tackles the issue employing an endpoint approach. Although the basic components were available in 2000, it was required that the target endpoints should be expanded in particular. Objective This study aimed at expanding the scope of damage function of ozone depletion in the LCIA framework of LIME. Damage function gives potential and quantitative damage for each endpoint per unit emission of ODS. Methods Marginal damage due to the unit emission of ODS was calculated for 13 substances for which quantitative information was available as follows: (1) the increase of UVB radiation at the earth's surface per unit emission of ODS was estimated, (2) the increase of potential damage per unit increase of UVB radiation was estimated, (3) the increase of potential damage per unit emission of ODS was determined by connecting the two relationships, and (4) correcting by the atmospheric lifetime of ODS, so that the damage function was then obtained. For other ODSs regulated by the Montreal Protocol, their damage functions were estimated by multiplying the ratio of ODP compared to the corresponding reference substance by the damage function of this reference substance. Results and Discussion The damage function of ozone depletion included the following endpoints: skin cancer and cataract for human health, crop production and timber production for social assets, and terrestrial NPP and aquatic NPP for primary productivity. And damage factors for each safeguard subject were also obtained. Conclusion The damage function of ozone depletion could cover all ODSs regulated by the Montreal Protocol and also cover important endpoints. Uncertainty of damage function is also an important point to be elucidated. Preliminary studies of uncertainty analysis have begun for the damage function of ozone depletion. However, further analysis is required to comprehensively evaluate the uncertainty of the damage function. - Abbreviations: BCC-Basal Cell Carcinoma; CFC-Chlorofluorocarbon; DALY-Disability Adjusted Life Years; DF-Damage Factor; DI-Damage Indicator; EESC-Equivalent Effective Stratospheric Chlorine; HBFC-Hydrobromofluorocarbon; HCFC-Hydrochlorofluorocarbon; LCA-Life Cycle Assessment; LCIA-Life Cycle Impact Assessment; LIME-Life-cycle Impact assessment Method based on Endpoint modeling; MM-malignant melanoma; NPP-Net Primary Production; ODP-Ozone Depletion Potential; ODS-Ozone Depleting Substance; SCC-Squamous Cell Carcinoma; TCL-Tropospheric Chlorine Loading; UVB-Ultraviolet B; YLD-Years of Life Disabled; YLL-Years of Life Lost.     

Aspergillus rhinitis in Wistar (Crl:(WI)BR) rats

In two separate 24 month studies on the carcinogenic effect of single cadmium chloride injections in male Wistar (CRl:(WI)BR) rats, a total of 22% (129/597) of animals studied histologically were found to have chronic suppurative rhinitis caused by Aspergillus fumigatus. The diagnosis was based on characteristic conidial heads present in the sections, and positive methenamine-Grocott (GMS) staining of septate hyphae with dichotomous branching at angles of 45 degrees. Fungal hyphae balls, surrounded by a wall of neutrophilic granulocytes, were found in areas of the naso- and maxilloturbinates and occasionally caused complete blockage of the nasal passages. The underlying tissue showed an inflammatory response. In sections from 32 of the 129 cases (25% of the cases), epithelial necrosis and hemorrhage were indicative of fungal tissue invasion, but without dissemination to other organs. The infection rate was unaffected by the cadmium treatment or the location of rats in different cages. Positive antibody titers to Sendai and sialodacryoadenitis viruses suggested that transient inflammation of the upper respiratory tract rendered the mucosa susceptible to the fungal infection. The infection appeared to be sustained by growth around foreign bodies (hairs and plant material). Although focal squamous cell metaplasia of the respiratory epithelium with hyperplasia and hyperkeratosis occurred more frequently in rats with Aspergillus rhinitis, the incidence of tumors of the nasal cavities was not affected.