Ultrastructure of Babesia equi trophozoites isolated in Minas Gerais, Brazil

A transmission electron microscope study was carried out on Babesia equi obtained from a splenectomized horse, from the municipality of Santa Luzia, Minas Gerais, Brazil. The isolate was inoculated into two splenectomized foals (1.05 x 10(10) parasitized erythrocytes by B. equi). Trophozoites have a single membrane in direct contact with the cytoplasm of the red blood cells, a prominent nucleus, well-developed rough and smooth endoplasmic reticulum, numerous free ribosomes and small food vacuoles. B. equi trophozoites have a cytostome and a long tubular feeding structure in direct contact with the blood plasma.

Eimerid coccidia from capybaras (Hydrochoerus hydrochaeris) in southern Bahia, Brazil

Two eimerid coccidia are reported in a capybara (Hydrochoerus hydrochaeris) population kept in captivity in the south of Bahia, northeastern Brazil (14º 47' 57.89"S and 39º 10' 10.58" W). Oocysts of Eimeria ichiloensis are subspheroidal to ellipsoidal, 26.2 x 21.7mm with bi-layered wall, the outer yellow and sculptured and the inner, dark and smooth. Residuum is absent, but usually 2-3 polar granules are present. Sporocysts are ovoid, 12.0 x 7.6mm. Stieda body and sporocyst residuum are present. Oocysts of Eimeria trinidadensis are subspheroidal to ellipsoidal, 22.2 x 19.6mm with bi-layered wall, the outer yellow and smooth, and the inner dark and smooth. Residuum is absent, but one polar granule is present. Sporocysts are ovoid, 11.0 x 6.9mm. Stieda body and sporocyst residuum are present. Based on these descriptions and previous ones it can be concluded that these coccidea species are widely dispersed in capybaras in South America.

Effect of different surface roughnesses on a turbulent boundary layer

The classical treatment of rough wall turbulent boundary layers consists in determining the effect the roughness has on the mean velocity profile. This effect is usually described in terms of the roughness function delta U+. The general implication is that different roughness geometries with the same delta U+ will have similar turbulence characteristics, at least at a sufficient distance from the roughness elements. Measurements over two different surface geometries (a mesh roughness and spanwise circular rods regularly spaced in the streamwise direction) with nominally the same delta U+ indicate significant differences in the Reynolds stresses, especially those involving the wall-normal velocity fluctuation, over the outer region. The differences are such that the Reynolds stress anisotropy is smaller over the mesh roughness than the rod roughness. The Reynolds stress anisotropy is largest for a smooth wall. The small-scale anisotropy and interniittency exhibit much smaller differences when the Taylor microscale Reynolds number and the Kolmogorov-normalized mean shear are nominally the same. There is nonetheless evidence that the small-scale structure over the three-dimensional mesh roughness conforms more closely with isotropy than that over the rod-roughened and smooth walls.

Pulmonary emphysema induced by passive smoking: an experimental study in rats

We describe a short time model for inducing experimental emphysema in rats by chronic tobacco smoke inhalation. Three groups of male Wistar rats (6 months old) were studied: controls (N = 8), rats intoxicated for 45 days (s-45, N = 7) or for 90 days (s-90, N = 8). The exposed animals were intoxicated 3 times a day (10 cigarettes per exposure period), 5 days a week. Pulmonary damage was assessed by means of functional tests and quantitative pathological examination of the airways and lung parenchyma. The s-45 and s-90 animals were similar in terms of functional residual capacity (FRC) corrected for body weight (FRC/kg) but both groups of smoking rats exhibited significantly higher FRC/kg values than the controls (s-45 = 6.33; s-90 = 6.46; controls = 3.78; P<0.05). When the two groups of smoking rats were pooled together and compared to controls, they showed decreased lung elastance (1.6 vs 2.19; P = 0.046) and increased mean linear intercept (Lm) (85.14 vs 66.44; P = 0.025). The s-90 animals presented higher inflammation and muscular hypertrophy at the level of the axial bronchus than the controls (P<0.05). When smoking groups were pooled and compared to controls, they presented significantly higher inflammation at the lateral level (P = 0.028), as well as airway secretory hyperplasia (P = 0.024) and smooth muscle hypertrophy (P = 0.005) at the axial level. Due to its simplicity, low cost and short duration, this technique may be a useful model to obtain new information about airspace remodeling due to chronic tobacco consumption

Use of blends of bioabsorbable poly(L-lactic acid)/poly(hydroxybutyrate- co-hydroxyvalerate) as surfaces for Vero cell culture

Vero cells, a cell line established from the kidney of the African green monkey (Cercopithecus aethiops), were cultured in F-10 Ham medium supplemented with 10% fetal calf serum at 37°C on membranes of poly(L-lactic acid) (PLLA), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) and their blends in different proportions (100/0, 60/40, 50/50, 40/60, and 0/100). The present study evaluated morphology of cells grown on different polymeric substrates after 24 h of culture by scanning electron microscopy. Cell adhesion was also analyzed after 2 h of inoculation. For cell growth evaluation, the cells were maintained in culture for 48, 120, 240, and 360 h. For cytochemical study, the cells were cultured for 120 or 240 h, fixed, processed for histological analysis, and stained with Toluidine blue, pH 4.0, and Xylidine ponceau, pH 2.5. Our results showed that cell adhesion was better when 60/40 and 50/50 blends were used although cells were able to grow and proliferate on all blends tested. When using PLLA/PHBV (50/50) slightly flattened cells were observed on porous and smooth areas. PLLA/PHBV (40/60) blends presented flattened cells on smooth areas. PLLA/PHBV (0/100), which presented no pores, also supported spreading cells interconnected by thin filaments. Histological sections showed that cells grew as a confluent monolayer on different substrates. Cytochemical analysis showed basophilic cells, indicating a large amount of RNA and proteins. Hence, we detected changes in cell morphology induced by alterations in blend proportions. This suggests that the cells changed their differentiation pattern when on various PLLA/PHBV blend surfaces.

Soil compaction and eucalyptus growth in response to forwarder traffic intensity and load

During timber exploitation in forest stands harvesting machines pass repeatedly along the same track and can cause soil compaction, which leads to soil erosion and restricted tree root growth. The level of soil compaction depends on the number of passes and weight of the wood load. This paper aimed to evaluate soil compaction and eucalyptus growth as affected by the number of passes and wood load of a forwarder. The study was carried out in Santa Maria de Itabira county, Minas Gerais State - Brazil, on a seven-year-old eucalyptus stand planted on an Oxisol. The trees were felled by chainsaw and manually removed. Plots of 144 m² (four rows 12 m long in a 3 x 2 m spacing) were then marked off for the conduction of two trials. The first tested the traffic intensity of a forwarder which weighed 11,900 kg and carried 12 m³ wood (density of 480 kg m-3) and passed 2, 4, and 8 times along the same track. In the second trial, the forwarder carried loads of 4, 8, and 12 m³ of wood, and the machine was driven four times along the same track. In each plot, the passes affected four rows. Eucalyptus was planted in 30 x 30 x 30 cm holes on the compacted tracks. The soil in the area is clayey (470 clay and 440 g kg-1 sand content) and at depths of 0-5 cm and 5-10 cm, respectively, soil organic carbon was 406 and 272 g kg-1 and the moisture content during the trial 248 and 249 g kg-1. These layers were assessed for soil bulk density and water-stable aggregates. The infiltration rate was measured by a cylinder infiltrometer. After 441 days the measurements were repeated, with additional analyses of: soil organic carbon, total nitrogen, N-NH4+, N-NO3-, porosity, and penetration resistance. Tree height, stem diameter, and stem dry matter were measured. Forwarder traffic increased soil compaction, resistance to penetration and microporosity while it reduced the geometric mean diameter, total porosity, macroporosity and infiltration rate. Stem dry matter yield and tree height were not affected by soil compaction. Two passes of the forwarder were enough to cause the disturbances at the highest levels. The compaction effects were still persistent 441 days after forwarder traffic.

Effects of traffic control on the soil physical quality and the cultivation of sugarcane

The cultivation of sugarcane with intensive use of machinery, especially for harvest, induces soil compaction, affecting the crop development. The control of agricultural traffic is an alternative of management in the sector, with a view to preserve the soil physical quality, resulting in increased sugarcane root growth, productivity and technological quality. The objective of this study was to evaluate the physical quality of an Oxisol with and without control traffic and the resulting effects on sugarcane root development, productivity and technological quality. The following managements were tested: no traffic control (NTC), traffic control consisting of an adjustment of the track width of the tractor and sugarcane trailer (TC1) and traffic control consisting of an adjustment of the track width of the tractor and trailer and use of an autopilot (TC2). Soil samples were collected (layers 0.00-0.10; 0.10-0.20 and 0.20-0.30 m) in the plant rows, inter-row center and seedbed region, 0.30 m away from the plant row. The productivity was measured with a specific weighing scale. The technological variables of sugarcane were measured in each plot. Soil cores were collected to analyze the root system. In TC2, the soil bulk density and compaction degree were lowest and total porosity and macroporosity highest in the plant row. Soil penetration resistance in the plant row, was less than 2 MPa in TC1 and TC2. Soil aggregation and total organic carbon did not differ between the management systems. The root surface and volume were increased in TC1 and TC2, with higher productivity and sugar yield than under NTC. The sugarcane variables did not differ between the managements. The soil physical quality in the plant row was preserved under management TC1 and TC2, with an improved root development and increases of 18.72 and 20.29 % in productivity and sugar yield, respectively.

Soil compaction by machine traffic and least limiting water range related to soybean yield

The research aimed to evaluate machine traffic effect on soil compaction and the least limiting water range related to soybean cultivar yields, during two years, in a Haplustox soil. The six treatments were related to tractor (11 Mg weight) passes by the same place: T0, no compaction; and T1*, 1; T1, 1; T2, 2; T4, 4 and T6, 6. In the treatment T1*, the compaction occurred when soil was dried, in 2003/2004, and with a 4 Mg tractor in 2004/2005. Soybean yield was evaluated in relation to soil compaction during two agricultural years in completely randomized design (compaction levels); however, in the second year, there was a factorial scheme (compaction levels, with and without irrigation), with four replicates represented by 9 m² plots. In the first year, soybean [Glycine max (L.) Merr.] cultivar IAC Foscarim 31 was cultivated without irrigation; and in the second year, IAC Foscarim 31 and MG/BR 46 (Conquista) cultivars were cultivated with and without irrigation. Machine traffic causes compaction and reduces soybean yield for soil penetration resistance between 1.64 to 2.35 MPa, and bulk density between 1.50 to 1.53 Mg m-3. Soil bulk density from which soybean cultivar yields decrease is lower than the critical one reached at least limiting water range (LLWR =/ 0).

Aerosol particle size distributions at a traffic exposed site and an urban background location in Oporto, Portugal

Aerosol size distributions from 6 to 700 nm were measured simultaneously at an urban background site and a roadside station in Oporto. The particle number concentration was higher at the traffic exposed site, where up to 90% of the size spectrum was dominated by the nucleation mode. Larger aerosol mode diameters were observed in the urban background site possibly due to the coagulation processes or uptake of gases during transport. Factor analysis has shown that road traffic and the neighbour stationary sources localised upwind affect the urban area thought intra-regional pollutant transport.

Soil penetration resistance in a rhodic eutrudox affected by machinery traffic and soil water content

Soil compaction caused by machinery traffic reduces crop yields. This study aimed to evaluate the effects of intensive traffic, and the soil water content, on the soil penetration resistance (PR) of a Rhodic Eutrudox (Distroferric Red Latosol, Brazilian Classification), managed under no-tillage (NT). The experiment consisted of six treatments: NT with recent chiseling, NT without additional compaction, and NT with additional compaction by 4, 8, 10 and 20 passes of a harvester with a weight of 100 kN (70 kN on the front axle). Undisturbed soil samples were collected at 5.5-10.5 cm and 13.5-18.5 cm depth to quantify the soil bulk density (BD). The PR was assessed in four periods, using an impact penetrometer, inserted in the soil to a depth of 46 cm. The effect of traffic intensities on the PR was small when this variable was assessed with the soil in the plastic consistency. Differences in PR among treatments increased as the soil water content decreased. The increase in the values of PR and BD was higher in the first passes, but the increase in the number of traffics resulted in deeper soil compaction. The machinery traffic effects on PR are better characterized in the friable soil consistency.

The effect of L-arginine on guinea-pig and rabbit airway smooth muscle function in vitro

We have investigated the effects of L-arginine, D-arginine and L-lysine on airway smooth muscle responsiveness to spasmogens in vitro. Both L-arginine and D-arginine (100 mM) significantly reduced the contractile potency and maximal contractile response to histamine but not to methacholine or potassium chloride in guinea-pig epithelium-denuded isolated trachea. Similarly, the contractile response to histamine was significantly reduced by L-arginine (100 mM) in rabbit epithelium-denuded isolated bronchus. The amino acid L-lysine (100 mM) failed to significantly alter the contractile potency of histamine in guinea-pig isolated trachea (P>0.05). In guinea-pig isolated trachea precontracted with histamine, both L-arginine and D-arginine produced a concentration-dependent relaxation which was not significantly altered by epithelium removal or by the presence of the nitric oxide synthase inhibitor, NG-nitro L-arginine methyl ester (L-NAME; 50 µM). Thus, at very high concentrations, arginine exhibit a non-competitive antagonism of histamine-induced contraction of isolated airway preparations that was independent of the generation of nitric oxide and was not dependent on charge. These observations confirm previous studies of cutaneous permeability responses and of contractile responses of guinea-pig isolated ileal smooth muscle. Taken together, the data suggest that high concentrations of arginine can exert an anti-histamine effect.

alpha-Smooth muscle actin and proliferating cell nuclear antigen expression in focal segmental glomerulosclerosis: functional and structural parameters of renal disease progression

The aim of the present study was to investigate the expression of alpha-smooth muscle actin (alpha-SM-actin) and proliferating cell nuclear antigen (PCNA) in renal cortex from patients with focal segmental glomerulosclerosis (FSGS) and their correlations with parameters of renal disease progression. We analyzed renal biopsies from 41 patients with idiopathic FSGS and from 14 control individuals. The alpha-SM-actin immunoreaction was evaluated using a score that reflected the changes in the extent and intensity of staining in the glomerular or cortical area. The PCNA reaction was quantified by counting the labeled cells of the glomeruli or renal cortex. The results, reported as median ± percentile (25th; 75th), showed that the alpha-SM-actin scores in the glomeruli and tubulointerstitium from the renal cortex were 2.0 (2.0; 4.0) and 3.0 (3.0; 4.0), respectively, in patients with FSGS, and 0.5 (0.0; 1.0) and 0.0 (0.0; 0.5) in the controls. The number of PCNA-positive cells per glomerulus and graded field of tubulointerstitium from the renal cortex was 0.2 (0.0; 0.4) and 1.1 (0.3; 2.2), respectively, for patients with FSGS, and 0.0 (0.0; 0.5) and 0.0 (0.0; 0.0) for controls. The present data showed an increase of alpha-SM-actin and PCNA expression in glomeruli and renal cortex from FSGS patients. The extent of immunoreaction for alpha-SM-actin in the tubulointerstitial area was correlated with the intensity of proteinuria. However, there was no correlation between the kidney expression of these proteins and the reciprocal of plasma creatinine level or renal fibrosis. These findings suggest that the immunohistochemical alterations may be reversible.

Effects of lipopolysaccharide on low- and high-density cultured rabbit vascular smooth muscle cells: differential modulation of nitric oxide release, ERK1/ERK2 MAP kinase activity, protein tyrosine phosphatase activity, and DNA synthesis

Previous studies have shown that exogenously generated nitric oxide (NO) inhibits smooth muscle cell proliferation. In the present study, we stimulated rabbit vascular smooth muscle cells (RVSMC) with E. coli lipopolysaccharide (LPS), a known inducer of NO synthase transcription, and established a connection between endogenous NO, phosphorylation/dephosphorylation-mediated signaling pathways, and DNA synthesis. Non-confluent RVSMC were cultured with 0, 5, 10, or 100 ng/ml of the endotoxin. NO release was increased by 86.6% (maximum effect) in low-density cell cultures stimulated with 10 ng/ml LPS as compared to non-stimulated controls. Conversely, LPS (5 to 100 ng/ml) did not lead to enhanced NO production in multilayered (high density) RVSMC. DNA synthesis measured by thymidine incorporation showed that LPS was mitogenic only to non-confluent RVSMC; furthermore, the effect was prevented statistically by aminoguanidine (AG), a potent inhibitor of the inducible NO synthase, and oxyhemoglobin, an NO scavenger. Finally, there was a cell density-dependent LPS effect on protein tyrosine phosphatase (PTP) and ERK1/ERK2 mitogen-activated protein (MAP) kinase activities. Short-term transient stimulation of ERK1/ERK2 MAP kinases was maximal at 12 min in non-confluent RVSMC and was prevented by preincubation with AG, whereas PTP activities were inhibited in these cells after 24-h LPS stimulation. Conversely, no significant LPS-mediated changes in kinase or phosphatase activities were observed in high-density cells. LPS-induced NO generation by RVSMC may switch on a cell density-dependent proliferative signaling cascade, which involves the participation of PTP and the ERK1/ERK2 MAP kinases.

Sleep disorders, sleepiness and traffic safety: a public health menace

Sleep disorders are not uncommon and have been widely reported throughout the world. They have a profound impact on industrialized 24-h societies. Consequences of these problems include impaired social and recreational activities, increased human errors, loss of productivity, and elevated risk of accidents. Conditions such as acute and chronic insomnia, sleep loss, excessive sleepiness, shift-work, jet lag, narcolepsy, and sleep apnea warrant public health attention, since residual sleepiness during the day may affect performance of daily activities such as driving a car. Benzodiazepine hypnotics and zopiclone promote sleep, both having residual effects the following day including sleepiness and reduced alertness. In contrast, the non-benzodiazepine hypnotics zolpidem and zaleplon have no significant next-day residual effects when taken as recommended. Research on the effects of wakefulness-promoting drugs on driving ability is limited. Countermeasures for excessive daytime sleepiness have a limited effect. There is a need for a social awareness program to educate the public about the potential consequences of various sleep disorders such as narcolepsy, sleep apnea, shift-work-related sleep loss, and excessive daytime sleepiness in order to reduce the number of sleep-related traffic accidents.

Structural properties of lipid reconstructs and lipid composition of normotensive and hypertensive rat vascular smooth muscle cell membranes

Multiple cell membrane alterations have been reported to be the cause of various forms of hypertension. The present study focuses on the lipid portion of the membranes, characterizing the microviscosity of membranes reconstituted with lipids extracted from the aorta and mesenteric arteries of spontaneously hypertensive (SHR) and normotensive control rat strains (WKY and NWR). Membrane-incorporated phospholipid spin labels were used to monitor the bilayer structure at different depths. The packing of lipids extracted from both aorta and mesenteric arteries of normotensive and hypertensive rats was similar. Lipid extract analysis showed similar phospholipid composition for all membranes. However, cholesterol content was lower in SHR arteries than in normotensive animal arteries. These findings contrast with the fact that the SHR aorta is hyporeactive while the SHR mesenteric artery is hyperreactive to vasopressor agents when compared to the vessels of normotensive animal strains. Hence, factors other than microviscosity of bulk lipids contribute to the vascular smooth muscle reactivity and hypertension of SHR. The excess cholesterol in the arteries of normotensive animal strains apparently is not dissolved in bulk lipids and is not directly related to vascular reactivity since it is present in both the aorta and mesenteric arteries. The lower cholesterol concentrations in SHR arteries may in fact result from metabolic differences due to the hypertensive state or to genes that co-segregate with those that determine hypertension during the process of strain selection.