Peripartum Ca and P homeostasis in multiparous sows fed adequate or excess dietary Ca.

The recent increased prevalence of uterine prolapses in sows around parturition has led to inferences that the prolapses may be associated with hypocalcemia. However, limited data are available to support that hypocalcemia occurs in sows. Hypocalcemia in dairy cows is associated with feeding excess dietary Ca during late gestation. The excess Ca is assumed to suppress homeostatic mechanisms critical to maintain serum Ca concentrations as the Ca demand increases during the early stages of lactation. In this experiment, sows were fed diets with excess Ca during late gestation and early lactation to assess the potential development of hypocalcemia in the peripartum period. Twelve crossbred (Large White × Landrace) multiparous gestating sows were fed a control diet (CON), 0.65% Ca to 0.38% standardized total tract digestible P (STTD P) and 0.67% Ca to 0.38% STTD P in gestation and lactation diets, respectively) or a high Ca diet (HCa, 1.75% Ca to 0.46% STTD P and 1.75% Ca to 0.45% STTD P in gestation and lactation diets, respectively). The diets were fed from gestation day 86 þ ± 1 until the end of lactation (27 þ ± 2 days period). On day 112 of gestation, indwelling venous catheters were placed in each sow. Blood samples were collected at 15-min intervals within four designated times (0700, 1000, 1300 and 1700 h) on gestation day 113 and lactation days 1, 3 and 5. Venous blood pH, gases (pO2, pCO2 and HCO3-), electrolytes (K+, Na+ and Cl-), ionized Ca (iCa), metabolites (glucose and lactate), plasma total Ca (tCa), and P were analyzed. Overall, sows fed HCa diet had greater (P < 0.001) concentrations of blood iCa and plasma tCa than sows fed CON diets. No clinical signs of Ca metabolism disorders were observed. Unexpectedly, concentrations of plasma P in sows fed HCa diets were lower (P < 0.001) than in sows fed CON diets. Plasma P tended to decrease (P = 0.057) as day of lactation increased. Differences between dietary treatments for blood pH, gases, electrolytes and metabolites were not detected (P > 0.05). No evidence for hypocalcemia was detected in peripartum sows fed CON or HCa diets. These data imply that excess Ca in late gestation diets did not result in hypocalcemia during the peripartum period. Future experiments should focus on factors other than hypocalcemia to identify causes of uterine prolapses in sows.

Effects of cytomegalovirus infection in human neural precursor cells depend on their differentiation state.

Cytomegalovirus (CMV) is the most common cause of congenital infection in developed countries and a major cause of neurological disability in children. Although CMV can affect multiple organs, the most important sequelae of intrauterine infection are related to lesions of the central nervous system. However, little is known about the pathogenesis and the cellular events responsible for neuronal damage in infants with congenital infection. Some studies have demonstrated that neural precursor cells (NPCs) show the greatest susceptibility to CMV infection in the developing brain. We sought to establish an in vitro model of CMV infection of the developing brain in order to analyze the cellular events associated with invasion by this virus. To this end, we employed two cell lines as a permanent source of NPC, avoiding the continuous use of human fetal tissue, the human SK-N-MC neuroblastoma cell line, and an immortalized cell line of human fetal neural origin, hNS-1. We also investigated the effect of the differentiation stage in relation to the susceptibility of these cell lines by comparing the neuroblastoma cell line with the multipotent cell line hNS-1. We found that the effects of the virus were more severe in the neuroblastoma cell line. Additionally, we induced hNS-1 to differentiate and evaluated the effect of CMV in these differentiated cells. Like SK-N-MC cells, hNS-1-differentiated cells were also susceptible to infection. Viability of differentiated hNS-1 cells decreased after CMV infection in contrast to undifferentiated cells. In addition, differentiated hNS-1 cells showed an extensive cytopathic effect whereas the effect was scarce in undifferentiated cells. We describe some of the effects of CMV in neural stem cells, and our observations suggest that the degree of differentiation is important in the acquisition of susceptibility.

Low-level subchronic arsenic exposure from prenatal developmental stages to adult life results in an impaired glucose homeostasis.

We evaluated how low-level (3 ppm) subchronic inorganic arsenic (iAs) exposure from prenatal developmental stages until adult life affects glucose homeostasis. Biochemical parameters of glucose and lipid metabolism, pancreatic insulin and glycosylated haemoglobin were determined in 4-month-old female offspring of adult Wistar rats. Pancreatic histology was also performed. Statistical comparisons between control and iAs-treated groups were performed by unpaired two-tailed Student's t-test. Statistical significance was set at p<0.05. We found that iAs treatment resulted in an impaired glucose tolerance test, suggestive of impaired glucose metabolism. This group was found to have hyperglycaemia and high levels of HOMA-IR, glycosylated haemoglobin, cholesterol and pancreatic insulin compared to control rats. However, plasma insulin, triglycerides and high-density lipoprotein cholesterol were not different from control rats. Moreover, ß-cell damage found in iAs-treated rats consisted of cells with a nucleus with dense chromatin and predominance of eosinophilic cytoplasm, as well as changes in the pancreatic vasculature. The current study provided evidence that subchronic iAs exposure at 3 ppm from prenatal developmental stages to adult life resulted in damage to pancreatic ß cells, affected insulin secretion and demonstrated altered glucose homeostasis, thus supporting a causal association between iAs exposure and diabetes.

Abnormal eating attitudes in Mexican female students: a study of prevalence and sociodemographic-clinical associated factors.

The objective of the study was to determine the prevalence of abnormal eating attitudes (AEA) in Mexican high school and university students in the city of San Luis Potosí, Mexico. By means of a transversal study with a weighted, random and multistage sampling process, we analyzed a representative sample of female students (N= 2006). The instrument was the Eating Disorder Inventory-2 (EDI-2), validated in Mexican population and a questionnaire of sociodemographic data. The prevalence of AEA was 12.6% and its frequency was significantly higher in high school than in university students. AEA cases were uniformly distributed among public and private institutions and a highly significant relationship between substances consumption and AEA was observed. A logistic regression model for AEA was obtained. Therefore, a profile of highly AEA was built based on sociodemographic data and a solid instrument validated in Mexican population, which can be employed as a screening and secondary prevention tool to design public health programs.

Decreased nitric oxide markers and morphological changes in the brain of arsenic-exposed rats.

Epidemiological studies demonstrate an association between chronic consumption of arsenic contaminated water and cognitive deficits, especially when the exposure takes place during childhood. This study documents structural changes and nitrergic deficits in the striatum of adult female Wistar rats exposed to arsenic in drinking water (3 ppm, approximately 0.4 mg/kg per day) from gestation, throughout lactation and development until the age of 4 months. Kainic acid injected animals (10mg/kg, i.p.) were also analyzed as positive controls of neural cell damage. Morphological characteristics of cells, fiber tracts and axons were analyzed by means of light microscopy as well as immunoreactivity to neuronal nitric oxide synthase (nNOS). As nitrergic markers, nitrite/nitrate concentrations, nNOS levels and expression of nNOS-mRNA were quantified in striatal tissue. Reactive oxygen species (ROS) and lipid peroxidation (LPx) were determined as oxidative stress markers. Arsenic exposure resulted in moderate to severe alterations of thickness, organization, surrounding space and shape of fiber tracts and axons, while cell bodies remained healthy. These anomalies were not accompanied by ROS and/or LPx increases. By contrast, except the expression of nNOS-mRNA, all nitrergic markers including striatal nNOS immunoreactivity presented a significant decrease. These results indicate that arsenic targets the central nitrergic system and disturbs brain structural organization at low exposure levels.

Effect of arsenic on regulatory T cells.

INTRODUCTION: Arsenic (As) affects the function and survival of lymphocytes, and some arsenic compounds exert a relevant antineoplastic effect. We have explored the effect of As on T regulatory cells. RESULTS AND DISCUSSION: In vitro experiments with peripheral blood mononuclear cells from healthy subjects showed that low concentrations of As tended to increase the number of natural T regulatory (nTreg) lymphocytes, whereas concentrations >5.0 muM had an opposite effect. Furthermore, rats exposed to As showed redistribution of nTreg cells, and As administration to rats with experimental allergic encephalomyelitis increased the levels of nTreg cells in spleen and diminished the severity of this condition. On the other hand, in 47 apparently healthy subjects chronically exposed to As, we found significant inverse correlation between urinary As levels and the number and function of nTreg lymphocytes. Although most of these individuals showed enhanced levels of apoptotic lymphocytes in peripheral blood, with a diminution of mitochondrial membrane potential, no significant correlation between these parameters and urinary As was detected. CONCLUSION: Our data indicate that As seems to have a relevant and complex effect on nTreg cells.

The effects of arsenic exposure on the nervous system.

Arsenic (As) is a common environmental contaminant widely distributed around the world. Human exposure to this metalloid comes from well water and contaminated soil, from fish and other sea organisms rich in methylated arsenic species, and from occupational exposure. It has been reported that human arsenic exposure causes several health problems such as cancer, liver damage, dermatosis, and nervous system disturbances such as polyneuropathy, EEG abnormalities and, in extreme cases, hallucinations, disorientation and agitation. Although there is evidence that arsenic exposure has a toxic effect on the nervous system there are few studies that address this issue. The purpose of this review is to describe what is presently known about the effects of arsenic compounds on the nervous system in humans and rodents and to discuss its possible mechanisms of action.

Methylmercury increases glutamate extracellular levels in frontal cortex of awake rats.

A current hypothesis about methylmercury (MeHg) neurotoxicity proposes that neuronal damage is due to excitotoxicity following glutamate uptake alterations in the astrocyte. By sampling from a microdialysis probe implanted in the frontal cortex of adult Wistar rats, we measured the effects of acute exposure to either 10 or 100 microM MeHg through the microdialysis probe, on glutamate extracellular levels in 15 awake animals. After baseline measurements, the perfusion of MeHg during 90 min induced immediate and significant elevations in extracellular glutamate at 10 microM (9.8-fold, P<.001) and at 100 microM (2.4-fold, P=.001). This in vivo demonstration of increments of extracellular glutamate supports the hypothesis that dysfunction of glutamate neurotransmission plays a key role in MeHg-induced neural damage.

Behavioral effects of exposure to endosulfan and methyl parathion in adult rats.

Endosulfan (ES) and methyl parathion (MP) are widely used in Latin America, and simultaneous exposure to both products is documented. This exposure may have effects on the nervous system because their targets include the GABAergic and cholinergic systems, which are main modulators of neuronal excitability in the cortex and hippocampus. We tested whether low-level, repeated exposure of adult rats to commercial formulations containing ES and MP disrupts spatial learning in the water maze. Five groups of eight animals received subcutaneously appropriate dilutions of the commercial formulations to yield the following treatments during 10 days: saline, 25 mg/kg ES, 2 mg/kg MP (MP(2)), 25 mg/kg ES plus 1 mg/kg MP (ES+MP(1)) and 25 mg/kg ES plus 2 mg/kg MP (ES+MP(2)). In addition, markers of neurological function, renal and hepatic damage were explored as potential consequences of exposure. In the absence of overt toxicity, the groups exposed to the ES plus MP showed significantly longer escape latencies, higher number of failures to reach the platform and more time in the periphery of the tank than the control and single-exposed groups. This finding shows that commercial formulations of ES and MP have marginal effects when administered individually but can produce behavioral alterations when given in combination.

Emergency off-pump coronary artery bypass grafting for acute left main coronary artery dissection.

We report the case of a 55-year-old woman with multiple comorbid conditions in whom acute left main coronary artery dissection occurred during attempted percutaneous transluminal coronary angioplasty. After the dissection, the patient underwent emergency off-pump coronary revascularization of the left anterior descending coronary artery and ramus intermedius with use of the left internal thoracic artery and a saphenous vein graft, respectively The procedure was successful. The risks and benefits of avoiding the extracorporeal circuit in this case of catheterization laboratory salvage are discussed herein, along with some of the concerns about anesthesia that contributed to our decision to perform the operation off-pump.

Effect of gender on outcomes of beating heart operations.

BACKGROUND: A worse outcome has been observed in women undergoing coronary artery bypass grafting (CABG) compared with men. We sought to determine whether this gender difference would be applicable in off-pump coronary artery bypass (OPCAB) procedures. METHODS: We compared outcomes among 187 consecutive patients undergoing OPCAB over a 12-month period by a single surgeon (J.H.L.). This study included 61 women and 126 men, representing 91% of all isolated CABG operations during the same time. RESULTS: The demographics were as follows: Women (n = 61) were older than men (n = 126) (67.5 versus 64.6 years; p = 0.05). They had a greater prevalence of congestive heart failure (28% versus 17%; p = 0.005), and were more frequently on intravenous nitroglycerin preoperatively (49% versus 32%; p = 0.05). Overall mortality was 1.6% (3 of 187). In-hospital complications were as follows: deaths 3.3% in women and 0.9% in men (p = 0.25); major bleeding 0% in women and 3.2% in men (p = 0.30); stroke 1.5% in women and 0% in men (p = NS). Mediastinitis or renal failure was not noted in either group. Extubation times (6.6 versus 6.1 hours; p = 0.001), surgical intensive care unit length of stay (43 hours versus 37 hours; p = 0.013), and postoperative length of stay (6.4 days versus 5.8 days; p = 0.014) were all significantly longer in women compared with men. When OPCAB women were compared with a matched cohort of women undergoing CABG, length of stay was similar, whereas OPCAB men realized a 13% reduction in length of stay compared with men undergoing conventional CABG (p = 0.002). CONCLUSIONS: Women presenting for OPCAB are older and have greater comorbidities than men. The elimination of cardiopulmonary bypass did not improve the recovery time of women, a finding that was strikingly different from the effect seen in men. These compelling results suggest that biochemical, hormonal, or pharmacokinetic factors in women may neutralize the anticipated beneficial effect of avoiding cardiopulmonary bypass.

In vivo hydroxyl radical formation after quinolinic acid infusion into rat corpus striatum.

We studied the effect of an acute infusion of quinolinic acid (QUIN) on in vivo hydroxyl radical (.OH) formation in the striatum of awake rats. Using the microdialysis technique, the generation of.OH was assessed through electrochemical detection of the salicylate hydroxylation product 2,3-dihydroxybenzoic acid (2,3-DHBA). The .OH extracellular levels increased up to 30 times over basal levels after QUIN infusion (240 nmol/microl), returning to the baseline 2 h later. This response was attenuated, but not abolished, by pretreatment with the NMDA receptor antagonist MK-801 (10 mg/kg, i.p.) 60 min before QUIN infusion. The mitochondrial toxin 3-nitropropionic acid (3-NPA, 500 nmol/microl) had stronger effects than QUIN on .OH generation, as well as on other markers of oxidative stress explored as potential consequences of .OH increased levels. These results support the hypothesis that early .OH generation contributes to the pattern of toxicity elicited by QUIN. The partial protection by MK-801 suggests that QUIN neurotoxicity is not completely explained through NMDA receptor overactivation, but it may also involve intrinsic QUIN oxidative properties.

The effects of sodium arsenite exposure on behavioral parameters in the rat.

Arsenic is a metalloid widely present in the environment. It is found in well water, soil, and air, and is also released from mining residues and industrial debris, among other anthropogenic sources. It has been previously reported that the content of catecholamines in striatum, hippocampus, and other cerebral regions changes in mice and rats exposed to arsenic. Few studies have examined behavioral alterations after intoxication with arsenic, and both increased and decreased locomotor activity, as well as learning deficits, have been described. In order to characterize the behavioral alterations induced by arsenic exposure, we exposed adult male Sprague-Dawley rats to 5, 10, and 20 mg/kg of arsenic by intragastric route for 2 or 4 weeks. Exposed rats showed reduced locomotor activity, which returned to control levels at the end of the intoxication period. We also found an increase in the number of errors in an egocentric task, alterations in monoamine content in midbrain and cortex, and increases in arsenic brain concentration, which were related to time of the exposure but not dose. These results indicate that short-term arsenic exposure induces neural and behavioral changes that may reflect a neurotoxic effect, and that these alterations are correlated to dose, time of exposure, and experimental conditions.

Effect of gender on fast-track recovery after coronary artery bypass graft surgery.

OBJECTIVE: To examine the effects of gender on time to extubation after coronary artery bypass graft (CABG) surgery and intensive care unit and hospital length of stay. DESIGN: Retrospective study comparing outcomes as related to gender. SETTING: Tertiary care university teaching hospital. PARTICIPANTS: Consecutive patients (n = 561; 376 men, 185 women) undergoing CABG surgery between January 1995 and December 1997. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Early extubation was possible in 74% of men versus 64% of women (p = 0.03); length of stay was < or =5 days in 60% of men versus 48% of women (p = 0.008); overall postoperative length of stay was 5.7 days for men versus 6.5 days for women (p = 0.003); morbidity and mortality were not significantly different between groups. CONCLUSION: Women undergoing CABG surgery with a standardized fast-track protocol have longer intubation times, intensive care unit length of stay, and hospital length of stay than their male counterparts.

Exposure to arsenic and lead and neuropsychological development in Mexican children.

This cross-sectional study examined the effects of chronic exposure to lead (Pb), arsenic (AS) and undernutrition on the neuropsychological development of children. Two populations chronically exposed to either high (41 children) or low (39 children) levels of As and Pb were analyzed using the Wechsler Intelligence Scale for Children, Revised Version, for México (WISC-RM). Geometric means of urinary arsenic (AsU) and lead in blood (PbB) were 62.9+/-0.03 (microgAs/g creatinine) and 8.9+/-0.03 (microg/dl) for the exposed group and 40.2+/-0.03 (microgAs/g creatinine) and 9.7+/-0.02 (microg/dl) for the reference group. The height for age index (HAI) was used as an indicator of chronic malnutrition and sociodemographic information was obtained with a questionnaire. Lead and arsenic were measured by atomic absorption spectrophotometry. Data on full, verbal, and performance intelligence quotients (IQ) scores, long-term memory, linguistic abstraction, attention span, and visuospatial organization were obtained through the WISC-RM. After controlling for significant potential confounders verbal IQ (P<0.01) decreased with increasing concentrations of AsU. The HAI correlated positively with full-scale and performance IQ (P<0.01). Higher levels of AsU were significantly related to poorer performance on WISC-RM factors examining long-term memory and linguistic abstraction, while lower scores in WISC-RM factors measuring attention were obtained at increasing values of PbB. Our results suggest that exposure to As and chronic malnutrition could have an influence on verbal abilities and long-term memory, while Pb exposure could affect the attention process even at low levels.

Effects of arsenite on central monoamines and plasmatic levels of adrenocorticotropic hormone (ACTH) in mice.

We studied the effects of chronic arsenic exposure on brain monoamines and plasma levels of adrenocorticotropic hormone (ACTH) of mice. After weaning, mice received arsenic (0, 20, 40, 60 or 100 ppm) in drinking water over a period of 9 weeks. Monoamine content was quantified in different brain regions, arsenic was quantified in brain tissue and ACTH levels in plasma. Brain arsenic concentrations up to 200 ng/g showed a significant correlation with exposure levels and produced slight modifications in regional monoamine levels. ACTH plasma levels were significantly associated with norepinephrine (NE) concentrations in the medulla and pons, but not with hypothalamic NE levels. ACTH levels were significantly higher in the group exposed to 20 ppm. Dopamine showed significant dose-related decreases in the hypothalamus. These results show that chronic sodium arsenite exposure produces changes in central monoamines, which are not associated on a dose-dependent basis with major alterations in plasma ACTH.

Clinical outcomes and resource usage in 100 consecutive patients after off-pump coronary bypass procedures.

BACKGROUND: Cardiopulmonary bypass initiates a cascade of inflammatory processes that may result in end-organ damage, leading to the increased prevalence of noncardiac complications. Therefore, off-pump coronary artery bypass graft (OP-CAB) procedures have recently been introduced into clinical practice. METHODS: This study was a case-controlled study that compared the outcomes and cost of 100 consecutive OP-CAB procedures with a control group of 100 contemporary matched conventional coronary artery bypass grafting procedures. All operations were performed by a single surgeon (J.H.L. ) and complete revascularization that used off-pump techniques was achieved with the use of innovative exposure techniques to the lateral and posterior wall vessels. RESULTS: An average of 3.1 grafts per patient were performed in the OP-CAB group (range, 1-5). The incidence of conversion to conventional coronary artery bypass grafting was 1%. The overall mortality rate was 2.0%. There were no instances of stroke, renal failure, or sternal infections in the OPCAB group. Thus, the OP-CAB group had a shorter length of stay (6.1+/-2.5 versus 7.1+/-3.3 d; P =.003), with a corresponding reduction in variable direct cost per case of 29% (P<.001). CONCLUSION: Our experience suggests that OP-CAB procedures are feasible for most patients who currently require complete revascularization. It is associated with very a low morbidity rate and may represent the ideal revascularization strategy for patients at high risk for undergoing cardiopulmonary bypass.