Identification and quantification of nuisance odors at a trash transfer station.

The objective of this study was to evaluate the effectiveness of a modified Odor Profile Method (OPM) at a trash transfer station (TTS). An updated Landfill Odor Wheel was used to define odor character and distinguish among odor sources. The Flavor Profile Analysis (FPA) intensity scale was used to rank the relative intensity of the various odor characters defined by the odor wheel and to understand how each odor profile changed off site. Finally, the odor wheel was used to select the appropriate chemical analysis to identify the odorants causing the odors identified by the human panelists. The OPM was demonstrated as an effective tool for characterizing and distinguishing odor sources at a TTS. Municipal solid waste (MSW) odors were characterized as rancid, sulfur, and fragrant; rancid odors were dominant in the odor profile on-site, while sulfur odors dominated off-site. Targeted chemical analysis was used to identify odorants potentially responsible for odors at the site. Methyl mercaptan (rotten vegetable) and hydrogen sulfide (rotten egg) were identified as the odorants most likely to be responsible for the sulfur odors at the site. Acetaldehyde (sweet, fruity), acetic acid (vinegar), and butyric acid (rancid) were identified as the odorants mostly likely to be causing the rancid and sour odors. Terpenes/pine odors were observed near the greenwaste pile. Results confirm that the OPM, together with properly selected chemical analyses, can be a useful tool for identifying and quantifying the sources of odors.

Veterinary antibiotics used in animal agriculture as NDMA precursors.

The formation of carcinogenic N-nitrosodimethylamine (NDMA) during chloramination at drinking water treatment plants has raised concerns as more plants have switched from chlorine to chloramine disinfection. In this study, a source of NDMA precursors that has yet to be investigated was examined. Veterinary antibiotics are used in large quantities at animal agricultural operations. They may contaminate drinking water sources and may not be removed during wastewater and drinking water treatment. Ten antibiotics used in animal agriculture were shown to produce NDMA or N-nitrosodiethylamine (NDEA) during chloramination. Molar conversions ranged from 0.04 to 4.9 percent, with antibiotics containing more than one dimethylamine (DMA) functional group forming significantly more NDMA. The highest formation for most of the compounds was seen near pH 8.4, in a range of pH 6 to 11 that was investigated. The effect of chlorine-to-ammonia ratio (Cl2/NH3), temperature, and hold time varied for each chemical, suggesting that the effects of these parameters were compound-specific.

The levo enantiomer of amphetamine increases memory consolidation and gene expression in the hippocampus without producing locomotor stimulation.

Dextro-amphetamine enhances memory and other cognitive functions in animals and humans. The use of d-amphetamine as a memory enhancer, however, is limited by a robust stimulatory side-effect profile caused by release of dopamine. The levo enantiomer of amphetamine has been shown to be considerably less effective as a dopamine releaser and less potent in producing the stimulatory effects characteristic of d-amphetamine. In order to determine whether l-amphetamine and the structurally related compound, l-methamphetamine, retain cognitive-enhancing effects despite their lack of stimulatory activity, we administered the compounds to rats prior to activity monitoring experiments, and in different animals, immediately after training on inhibitory avoidance and object recognition tasks. Results demonstrated that l-amphetamine and l-methamphetamine did not increase locomotion and stereotypies beyond control levels, but did produce significant memory enhancement. In addition, l-amphetamine and l-methamphetamine alleviated scopolamine-induced amnesia in the inhibitory avoidance task. In all cases, these compounds produced an effect comparable to that of d-amphetamine, but required only one quarter of the d-amphetamine dose to produce the same effect size. We also found that l-amphetamine modulates learning-induced changes in hippocampal Arc/Arg3.1 protein synthesis that correlate with memory consolidation. These results suggest that l-amphetamine and l-methamphetamine are potent memory enhancers in rats and may ultimately be useful for treating memory disorders in humans.

Evolution epidemiologique et bacteriologique des meningites purulentes au CHu de Treichville de 1980 a 2004

INTRODUCTION :Notre etude a ete realisee a partir de S895souches de germes responsables de meningites purulentes au cours des examens cytobacteriologiques du LCR; provenant des malades atteints de meningites bacteriennes et hospitalises dans les differents services du CHUT que sont: le SMIT; la pediatrie et les autres services (PPH; Medecine interne)Les objectifs sont de deux types:OBJECTIF GENERAL: c'est l'etude du visage epidemiologique et bacteriologique des meningites bacteriennes depuis l'introduction de la vaccination anti-meningococcique et anti-Hib.OBJECTIFS SPECIFIQUES qui sont:-d'identifier les bacteries responsables de meningites bacteriennes au cours de ces 25 ans-de decrire la repartition epidemiologique de ces bacteries-de decrire le comportement de ces bacteries vis-a-vis des antibiotiquesMETHODOLOGIE: Il s'agit d'une etude historique a visee descriptive et analytique portant sur des theses et des publications sur les meningites bacteriennes diagnostiquees du 1er Janvier 1980 au 31 Decembre 2004 au C.H.U. de Treichville.RESULTATS : Il ressort de notre etude:- le pneumocoque occupe la premiere place des etiologies des meningites bacteriennes avec une frequence de 41;54pour cent devant les germes tiquetes autres germes; l'Hi; et le meningocoque.-Age; Les adultes sont les plus touches avec 54;84pour cent. Tous les germes etant concernes sauf 1'Hi-Une emergence de meningocoque B et l'apparition de meningocoque W135-Une baisse de la frequence des meningites a Hi-Seul le pneumocoque subit une influence saisonniere (saison seche)-La sensibilite des principaux germes vis-a-vis des antibiotiques utilises dans I traitement des meningites purulentes baisse d'annee en annee pour l'ampicilline et le chloramphenicol; est conservee pour le cefotaxime et les cephalosporines de 3eme generation.CONCLUSION: Le visage epidemiologique et bacteriologique des meningites a change surtout en ce qui concerne les meningites a meningocoque.Nous notons une baisse de la frequence des meningites a Hi. Aussi recommandons nous une vaccination antimeningococcique de masse appropriee et l'introduction du vaccin anti-Hib dans la PEV

Additional evidence for an association between the dopamine D4 receptor (D4DR) exon III seven-repeat allele and substance abuse in opioid dependent subjects: relationship of treatment retention to genotype and personality.

The long form of the dopamine D4 receptor (D4DR) exon III repeat polymorphism has been linked in some but not all studies to impulsive, extravagant and novelty-seeking personality traits that are prominent in affiliated behaviours such as attention deficit disorder and substance abuse. In particular, we have reported previously an increased frequency of the long seven-repeat D4DR exon III allele in a group of 141 opioiddependent subjects compared to 110 control subjects. In order to further substantiate the role of D4DR in contributing to heroin addiction we have genotyped an additional, smaller cohort of opioid-dependent subjects. In this new group of 57 opioid-dependent subjects compared to an expanded group of 143 control subjects a significant difference was observed in overall genotype frequency (p=0.04). An excess of the seven-repeat allele of the D4DR receptor gene was also observed compared to control subjects (p=0.06). The frequency of the seven-repeat allele is 15.8% in the heroin addict population vs. 8.1% in the control group, conferring a relative risk of 2.07 (95% CI: 0.98-4.38). An association between two polymorphisms considered together (D4DR and dopamine D3 receptor) and treatment retention was observed (p=0.02). In a subgroup of 38 opioid-dependent subjects, who were successfully administered the TPQ, higher Harm Avoidance (p< 0.001) and Novelty Seeking (NS3; extravagant vs. reserved, p< 0.001) scores were found. In contrast to some previous reports, no relationship was apparent between TPQ scores and treatment retention in this small group of opioid-dependent subjects.

Theoretical considerations on cell ensembles.

Structure-function interdependency must apply at the supracellular level as well as at cellular and molecular levels. The overall structure and the intercellular geometry of the multicellular erythroblastic island, although strongly dependent upon molecular interactions (which determine or modulate recognition, adhesion, and the like), also carry consequences at a more general physical-chemical level. These relate to such factors as local concentrations and gradients, the nature of the forces and the phase-state of the material in the intercellular region, the generalized intercellular transport processes (diffusional, osmotic, electrokinetic, hydrodynamic, etc.), and the dynamic coupling of flows. Such "other-level" phenomena must play a significant role, and therefore must be taken into account, in formulating a comprehensive picture of the ways in which the microenvironment acts in the management and control of the processes of hematopoietic differentiation and development.

Osmotic fragility model for red cell populations.

A model that predicts the osmotic fragility curve of a red cell population is developed by relating the critical osmotic pressure to the size distribution of the cells, determined by resistive pulse spectroscopy. Two of the parameters involved, namely the normalized osmotic volume correction, B, and the swelling index, k, are previously determined from the experimental average properties of the population. From these values the critical volume of the cell is obtained, and is shown to be 6-12% larger than the first spherical volume, obtained from an independent experiment. A new parameter, n, a measure of the surface area distribution of the cells, is incorporated through a simple function that relates the critical volume to the size of the cells, and is theoretically shown to be linked to parameters k and B. The model is used to fit and interpret fragility data obtained in this laboratory for normal and sickle cell samples. From the values of n obtained for normal samples, the model predicts an essentially constant surface-to-volume ratio within an individual's cell population. For sickle cell samples, instead, the value of index n is negative, thereby supporting an increase in excess surface area as cell size decreases. Both findings are in agreement with direct observations reported in the literature. It is concluded that this set of parameters may be used to develop an index classification of blood disorders.

Membrane and cytoplasmic resistivity properties of normal and sickle red blood cells.

The cytoplasmic resistivities and membrane breakdown potentials of normal (AA), sickle-cell-trait (AS), as sickle (SS) red blood cells have been measured by the biophysical methodology of resistive pulse spectroscopy over a range of osmolalities. At isotonicity, the average membrane breakdown potentials are virtually identical for the three types of cells occurring at about 1150 V/cm. Average isotonic cytoplasmic resistivities are somewhat higher for the SS cells (166.7 +/- 7.49 ohm-cm) compared to the AA (147.6 +/- 1.98 ohm-cm) or AS cells (148.7 +/- 1.79 ohm-cm). As medium osmolality is varied, the differences in resistive properties become enlarged, especially at very low and very high osmolalities. At high osmolalities, both types of sickle cells show a large increase in internal resistivity compared to the normals; at low osmolality, the SS samples exhibit a distinctly different membrane breakdown characteristic, decreasing in this parameter, whereas the other two groups increase. Of the 15 SS samples tested, three displayed much higher cytoplasmic resistivities at isotonicity: 218.2 +/- 5.25 ohm-cm, compared to an average of 153.5 +/- 3.46 ohm-cm for the other 12. The relationship between these high resistivities and the subfraction of irreversibly sickled cells in the sample is discussed.

Alternative interpretation for the osmotic response of human erythrocytes.

In a recent publication, Heubusch et al. (J Cell. Physiol, 122:266-272, 1985) reported changes of erythrocyte volume measured by the Coulter counter technique over a wide range of osmolalities (160 to 3000 m0sm). Their results showed a partially hindered, nonlinear response, in contrast to classical observations made over more restricted osmolality ranges, using other methods. The authors suggested the underlying cause of this behavior to be a mechanical resistance of the membrane cytoskeleton. In this paper, we wish to offer a different interpretation of their results on erythrocyte osmotic behavior, based on similar experiments carried out in our laboratory, and supported by previous analyses from the literature. In particular, it is shown that the shape-factor correction to the electronic sizing measurement can correctly account for the observed deviations from linearity in the hypotonic range. In contrast, increased chemical nonideality and eventual hemolysis are the likely factors responsible for the behavior in the hypertonic range.

Deformability and other rheological interactions of red blood cells in electronic cell sizing.

The red blood cell apparent-size spectrum, obtained using resistive pulse spectroscopy (RPS) with typical electrical response times, is characterized by a bimodality, which in turn is quantified by a bimodality index. The magnitude of the index reflects the nonuniformity in distribution of particle trajectories within the orifice, itself a function of cell deformability. In measurements of mixed populations of glutaraldehyde-fixed and native cells, the index is found to be linearly dependent on the fraction of deformable cells. The index, previously known to be a function of flow rate, is now found to be a function of the electric field strength within the orifice as well. Furthermore a previously reported time-dependent loss of bimodality, for the uncounted cells remaining in a counting-vial suspension, appears to be a function of the electric field strength far outside the orifice. The relationship between the pressure drop across the orifice and the average linear fluid velocity through the orifice has been measured, and it is concluded that the flow within the orifice is non-turbulent, at all but the highest flow rates. The non-turbulent flow condition, coupled with the short resident time within the orifice, implies that the observed selection of different trajectories (as a function of cell deformability) must take place well in front of the orifice.

Time-evolution of erythrocyte physico-chemical properties in blood stored at different temperatures.

Several interrelated biophysical and biochemical properties of erythrocytes and plasma from whole blood stored at 4 degrees C, and 37 degrees C with CPD preservative were determined over a 21-day period. Changes in red cell volume, deformability and osmotic fragility (all measured by resistive pulse spectroscopy) showed some surprising fine structure that correlated well with dynamic variations in extracellular species, especially sodium, potassium and lactate dehydrogenase. Several features of these data suggest the existence of three distinct stages of cell condition, apparently not recognized previously. Changes are interpreted primarily in terms of membrane behavior, and implications for storage monitoring are discussed.

Measurement of biophysical properties of red blood cells by resistive pulse spectroscopy: volume, shape, surface area, and deformability.

This paper presents a simple, new approach to the determination of size, shape, surface area, and deformability information for cells, notably red blood cells. The results are obtained by combining experimental measurements from resistive pulse spectroscopy (an extension of electronic cell-sizing methodology) with theoretical calculations for model cell systems. Assuming constancy of surface area and approximating red cell shapes by both prolate and oblate ellipsoids of revolution, values are determined for cell shape factor and volume under a variety of conditions. For red blood cells under low-stress conditions, shape factor, volume, and surface area results are found to be consistent with those available from the literature, when the oblate model is used. The applicability of this approach for determination of red cell properties under altered conditions is demonstrated by results for cell volume, at varying osmotic pressure and mechanical shear (tensile) stress. By quantitating the change in cell shape with stress, a new numerical scale for measuring cell deformability is also obtained, and data are presented on its variation for red cells at different osmolalities, over the range of 140 to 500 mOsm.

Temperature effects on osmotic fragility, and the erythrocyte membrane.

Results are reported on the temperature-dependence of intact-cell surface area, isotonic volume, hemolytic volume, and ghost steady-state surface area and volume, using several techniques of resistive pulse spectroscopy. Temperature was found not to alter the intact cell surface area permanently: the area remains constant at 130 +/- 1 micron 2, at temperatures ranging from 0 to 40 degrees C. Temperature does alter the steady-state volume of the cells, with a colder temperature inducing swelling by about 0.29 micron 3/deg. C. Such a temperature-induced volume change is sufficient to explain only approximately half of the fragility differences which result from temperature changes. The remainder was found to result from higher temperatures enabling a substantial transient increase in surface area of intact cells (up to at least 14% of 40 degrees C), with a corresponding increase in the cell's hemolytic volume (up to 21%). The hemolytic volume apparently increases linearly with temperature, since steady-state ghost volumes are found to increase linearly with the temperature at which the ghosts were produced. In the steady state (at high temperature), the membranes of electrically-impermeable resealed ghosts can remain extended by more than 10%, compared with membranes of the corresponding unhemolyzed, intact red cells.

Erythrocyte and ghost cytoplasmic resistivity and voltage-dependent apparent size.

Particle resistivity is explicitly included in the equations relating volume to voltage pulse, in electronic cell sizing or resistive pulse spectroscopy (RPS). It has long been known that in high electric fields cell resistivity decreases as the membrane undergoes dielectric breakdown. At sufficiently high electric field strengths, well past dielectric breakdown, the red cell membrane becomes electrically transparent, or nearly so, and apparent cell size becomes essentially a function of the cytoplasmic resistivity. Electronic cell sizing is traditionally carried out at low electric field strengths, and corrections made for the influence of cell shape by use of the Laplace equation. We find the Laplace solution to be still applicable at very high electric field strengths for purposes of calculating specific cytoplasmic resistivity from RPS measurements. Our value for discocytes, 220 omega X cm, is in good agreement with published results obtained by other researchers using other techniques. We have also applied these same procedures to determine the time course of voltage-dependent resistivity changes in ghosts and intact spherocytes, during the first 5 min after suspension in hypotonic medium. We believe these to be the first explicit calculations of particle specific resistivity from post-dielectric-breakdown apparent size, using traditional electronic sizing techniques.

Osmotic hemolysis and fragility. A new model based on membrane disruption, and a potential clinical test.

Red cell osmotic hemolysis has traditionally been defined by the loss of hemoglobin, in response to reduced osmotic pressure, as measured spectroscopically. Previous work from this laboratory using resistive pulse spectroscopy (RPS) has shown that in a mixed population of hemolyzing cells, ghosts can be detected as being more deformable, and hence appearing distinctly smaller, than the remaining intact cells. Other researchers using similar methods have reported detection of ghosts as apparently smaller objects, resulting from their greater sensitivity to dielectric breakdown. We now confirm both of these results, and demonstrate by kinetic studies that changes which occur in the rheological and electrical properties of ghosts are independent phenomena. We include in our analysis the explicit calculation of ghost and intact spherocyte resistivity after dielectric breakdown. The two different characterizations for ghosts are integrated into a proposed model of osmotic hemolysis based on known red blood cell membrane and cytoplasmic properties. This work provides both a theoretical and a practical foundation for RPS-based measures of osmotic fragility, including a potential new clinical test, measures which provides very early detection of the ultimate fate of osmotically stressed red cells.

Biophysical responses of red cell-membrane systems to very low concentrations of inorganic mercury.

Changes in red blood cell size, deformability, and osmotic fragility are indicators of altered condition and/or altered regulatory processes at the whole cell and membrane levels. An agent, such as HgCl2, that brings about specific changes of this kind can therefore serve as a selective probe of such cell condition and regulatory state. Conversely, for a health-threatening agent "active" in this way, the cell-membrane responses serve to clarify the more fundamental bases of its toxicity, as well as to permit identification and characterization of its early and low-level actions on living systems. Taking advantage of recent advances in the technique of "resistive pulse spectroscopy," we present a coordinated study of these three interrelated biophysical properties for the interactions of HgCl2 with human red cells. We thereby are able to extend previous studies of this kind into domains of shorter time (instantaneous exposures), lower level exposures (down to 10(-9) M, well below the level of acute human toxicity), as well as to additional kinds of responses (e.g., "dynamic osmotic hemolysis"). For conditions ranging from 10(-4) to 10(-9) M in HgCl2, for instantaneous to 90-min-incubated exposures, for medium osmolarities from 120 to 300, the matrix of observed cell responses includes relative swelling as well as shrinkage, changes in deformability, and both enhancement of and protection against osmotic hemolysis. Some unexpected short-term effects of time and temperature of storage of blood cell stock samples, with respect to increasing and decreasing osmotic fragility, are also reported. These apparently disparate results are interpreted in terms of mercury interactions with cell and membrane SH groups, and a reasonable rationale is presented for most of the responses in terms of disruption of passive and active Na+-K+, gradient controls, plus interactions with cellular proteins.

Some remarks on red cell shape and on surface and volume relationships.

Red cell (RBC) form is of interest for its own sake and for its role in characterizing physiologically altered and pathological cell types. RBC shape is also identified as one of the three principal factors enabling (and limiting) flow-induced cellular deformability processes. It has become common practice to discuss and analyze RBC form in terms of the ratio of the cell's surface area to its volume, and indeed to use the two concepts interchangeably. The inadequacy of the S/V ratio to serve this purpose is pointed out, a long with the qualitative and quantitative errors that it leads to, with cells of either very small size (as in iron-deficiency anemia) or large size (as in Addison's associated anemia). The substitution of a normalied, dimensionless, relative surface-to-volume function that can accurately quantitate this facet of form is necessary. The relationship between this function and other measures of form and "sphericity" are specified, and some applications of these functions to studies on cell form and deformability are indicated.