Optical Density Units Research Articles

Detection of high level of enterotoxin of Clostridum perfingens types C and D in small ruminants in Nigeria

Isolates of Clostridium perfringens from small ruminants in different ecological zones in Nigeria were been investigated to determine the enterotoxin levels in live animals (goats/sheep). A total of 342 fecal samples were collected for the study and out of this number 91 isolates were lecithinase positive. The 91 isolates were characterized into types C and D using the enzyme-linked immunosorbent assay (ELISA). The enterotoxin levels were observed after extensive laboratory analysis using reference strains ATCC 8504D and NCTC 3180C as control. The ELISA method was able to detect as low as 0.1 μg/ml of enterotoxin corrected optical density (OD) at 405 nm, although the values were found to fluctuate with the dilution coefficient. The value of 0.4 OD units was used to estimate the enterotoxin levels of the isolates, and mean value of 0.66 OD units for C. perfringens type D, while the mean value of 0.94 OD units for C. perfringens type C were obtained. It was observed that the sampled animals have high levels of C. perfringen types C and D, which are responsible for causing enterotoxaemia, especially the type D strains. It was also observed that animals having high levels of enterotoxins could move about without showing the signs of illness until found dead or exhibiting the acute form of the disease, enterotoxaemia. This showed the level of tolerant of animals, the West African Dwarf goats and sheep reared in these zones.

A case of ocular myasthenia gravis and Miller-Fisher syndrome

A40-year-old Chinese man with myasthenia gravis presented to the emergency department with worsening of ocular symptoms and the authors were asked for an opinion. He first presented 7 years ago with diplopia and ptosis that were responsive to edrophonium. His acetylcholine receptor antibody titre was elevated at 0.8 optical density unit (ODU) (laboratory reference <0.43 ODU), although repetitive nerve stimulation study did not produce a significant motor potential decrement. He improved with regular pyridostigmine (40 mg three times a day) but there was still mild ptosis and limited abduction of his left eye. His condition did not change in the last few years. For the current presentation, he had progressive deterioration of ocular movements over 1 week. Physical examination showed complete ophthalmoplegia bilaterally, partial ptosis of the left eye and absent pupillary light reflex in the right. Intravenous edrophonium 10 mg produced minimal improvement in right eye abduction. On further questioning, he also complained of numbness of his extremities, difficulties in fine hand functions, and unsteadiness while walking. He recalled a flu-like illness 2 weeks before the neurological symptoms. All his tendon reflexes were unobtainable and he had an ataxic gait. There was no demonstrable limb or facial weakness. Cerebrospinal fluid analysis showed increased protein concentration at 1.33 g/litre (reference range 0.12–0.6 g/litre) with total cell count of <1×106/litre. Anti-GQ1b antibody level was elevated at 43 enzyme immunoassay (EIA) Units (reference range <10 EIA). Nerve conduction studies only showed marginal reduction of F-wave persistence in the upper limbs. Magnetic resonance imaging of his brain revealed no abnormalities. Miller-Fisher syndrome (MFS) was diagnosed. He was treated with three sessions of plasmapheresis. His symptoms started to improve over the next week and he subsequently made a full clinical recovery. Moreover, he was completely free from his myasthenia gravis-related ophthalmoplegia in the following 2 months. Pyridostigmine was later recommenced when his baseline symptoms returned.

Use of Gradient Plates To Study Combined Effects of Temperature, pH, and NaCl Concentration on Growth of Monascus ruber van Tieghem, an Ascomycetes Fungus Isolated from Green Table Olives

The effect of temperature, pH, and sodium chloride concentration on the growth of the Ascomycetes fungus Monascus ruber van Tieghem, the main spoilage microorganism during storage of table olives, was studied by using the gradient plate technique. Gradients of NaCl (3 to 9%, wt/vol) at right angles to gradients of pH (2 to 6.8) were prepared for the plates, which were incubated at 25, 30, and 35 degrees C. Visible fungal growth, expressed in optical density units, was recorded by image analysis and graphically presented in the form of three-dimensional grids. Results obtained from the plates indicated that the fungus was salt and acid tolerant, being able to grow at NaCl concentrations of up to 9% (wt/vol) and pH values of as low as 2.2, depending on the incubation temperature. The inhibitory effect of NaCl increased as the pH decreased progressively at 25 and 30 degrees C but not at 35 degrees C. Growth was better at 30 and 25 degrees C as judged by the larger extent of the plates covered by mycelium compared with that at 35 degrees C, where no growth was observed at pHs below 3.7. Differentiation between vegetative (imperfect-stage) and reproductive (perfect-stage) growth was evident on all plates, providing useful information about the effect of environmental conditions on the form of fungal growth. When the growth/no-growth surface model was obtained by applying linear logistic regression, it was found that all factors (pH, NaCl, and temperature) and their interactions were significant. Plots of growth/no-growth interfaces for P values of 0.1, 0.5, and 0.9 described the results satisfactorily at 25 and 35 degrees C, whereas at 35 degrees C the model predicted lower minimum pH values for growth in the range of 7 to 10% NaCl than those observed on the plates. Overall, it is suggested that the fungus cannot be inhibited by any combination of pH and NaCl within the limits of the brine environment, so further processing is required to ensure product stability in the market.

Endobronchial Gene Transfer of Soluble Type I Interleukin-1 Receptor Ameliorates Lung Graft Ischemia-Reperfusion Injury

Soluble type I interleukin-1 receptor is a competitive inhibitor of interleukin-1 and may reduce its proinflammatory actions. The objective of this experiment was to demonstrate that endobronchial gene transfer of soluble type I interleukin-1 receptor IgG to donor lung grafts reduces posttransplant ischemia-reperfusion injury. All experiments utilized an orthotopic left lung isograft transplant model. Donors were divided into three groups (n = 6 each) for endobronchial transfection: group I received 2 x 10(7) plaque-forming units of adenovirus encoding soluble type I interleukin-1 receptor IgG; group II received 2 x 10(7) plaque-forming units of nonfunctional control adenovirus encoding beta-galactosidase; and group III received 0.1 mL of saline. Left lungs were harvested 24 hours after transfection and stored for 18 hours before transplantation. Graft function was assessed 24 hours after reperfusion using three measurements: isolated graft oxygenation, wet-to-dry lung weight ratio, and tissue myeloperoxidase activity. Transgene expression of soluble type I interleukin-1 receptor IgG was also evaluated using enzyme-linked immunosorbent assay and immunohistochemistry. Isolated graft arterial oxygenation was significantly improved in group I compared with groups II and III (281.8 +/- 134.8 versus 115.7 +/- 121.5 and 88.0 +/- 58.9 mm Hg, p = 0.0197 and p = 0.0081, respectively). Myeloperoxidase activity was also significantly reduced in group I compared with groups II and III (0.083 +/- 0.044 versus 0.155 +/- 0.043 and 0.212 +/- 0.079 optical density units per minute per milligram protein, p = 0.0485 and p = 0.0016, respectively). Expression of soluble type I interleukin-1 receptor IgG was detected only in lungs from group I. Endobronchial gene transfer of soluble type I interleukin-1 receptor IgG to donor lung grafts subjected to prolonged cold ischemia ameliorates ischemia-reperfusion injury by improving graft oxygenation and reducing lung edema and neutrophil sequestration.

Morphologically normal sperm have significantly greater total-RNA content than abnormal sperm

Introduction: Previous studies have demonstrated the presence of ribonucleic acid (RNA) in mature, ejaculated sperm and that sperm with poor motility have significantly more RNA than good motility sperm. However, no studies have investigated the relationship between RNA content and sperm morphology. Therefore, the study objective was to determine the relationship between total RNA content and sperm morphology. Methods: Sperm samples were separated by density centrifugation (Promotor, CERES Fertility, San Diego, CA) into morphologically normal and abnormal populations. Sperm morphology scores were determined by strict criteria. Total RNA was extracted from sperm via the Roche (Indianapolis, IN, USA) RNA isolation kit. Total RNA (μg of RNA per million sperm cells) recovered per sperm population from each ejaculate was determined by spectrophotometer and calculated as follows: (absorbance at 260 nm)×(conversion factor)×(dilution factor). The conversion factor for RNA is 0.04 μg/μl per optical density unit at 260 nm. Total RNA purity was calculated as the absorbance at 260 nm divided by the absorbance at 280 nm. Data were analyzed by Student's t-test. Results: A total of 179 semen specimens from different men underwent RNA extraction and analysis as described. All samples had absorbance readings between 0.1 and 1.0 at 260 nm and were determined to be accurate. Total RNA purity estimates for all samples were within the acceptable ratio of 1.7 and 1.9. RNA content in morphologically normal sperm (2.83±0.14 μg/10 6 cells) was significantly higher ( P<0.05) than the amount found in morphologically abnormal sperm (2.26±0.23 μg/10 6 cells). Conclusions: Ribonucleic acid content is significantly lower in morphologically abnormal sperm. Morphologically abnormal sperm may have impaired transcriptional and, or translational pathways thus negatively impacting cell function.

Differences in atrial versus ventricular remodeling in dogs with ventricular tachypacing-induced congestive heart failure.

Congestive heart failure (CHF) causes arrhythmogenic remodeling in both atria and ventricles, but differences between atrial and ventricular remodeling in CHF have not been well characterized. We examined atrial and ventricular tissues from dogs with CHF induced by ventricular tachypacing (220-240/min) for 0 (control) or 24 h, or 1, 2 or 5 weeks. Histopathology was used to assess apoptosis, fibrosis, white blood cell infiltration and cell death, ELISA to measure angiotensin-II concentration and Western blot to evaluate protein expression. Ventricular tachypacing-induced CHF was associated with substantially more fibrosis in left atrium (maximum 10 +/- 1% at 5 weeks) than in left ventricle (0.4 +/- 0.1% at 5 weeks, P < 0.01 versus left atrium). Tissue angiotensin-II concentration increased to steady state in atrial tissue at 24 h but increased more slowly in left ventricle, with a maximum that was significantly higher in atrium than ventricle. Ventricular tachypacing caused tissue apoptosis, inflammatory cell infiltration and cell death, with maximum changes in left atrium being faster, transient and larger than in left ventricle. Mitogen activated protein kinase activation was rapid (within 24 h) in left atrium, but smaller and slower (p38, c-Jun N-terminal kinase) or non-significant (extracellular signal-related kinase) in left ventricle. The 25-kDa activated form of transforming growth factor-beta1, a particularly important profibrotic mediator in atrium, increased significantly in left atrium, from 2.6 +/- 0.6 (control) to 9.2 +/- 1.7 (24 h) and 8.1 +/- 1.8 optical density units (1 week), but was not significantly changed in ventricle. There are qualitative and quantitative differences in atrial versus ventricular remodeling in experimental ventricular tachypacing-induced CHF, with potentially important consequences for understanding underlying mechanisms and developing new therapeutic approaches.

Statistical evaluation of mathematical models for microbial growth

The aim of this study was to evaluate the suitability of several mathematical functions for describing microbial growth curves. The nonlinear functions used were: three-phase linear, logistic, Gompertz, Von Bertalanffy, Richards, Morgan, Weibull, France and Baranyi. Two data sets were used, one comprising 21 growth curves of different bacterial and fungal species in which growth was expressed as optical density units, and one comprising 34 curves of colony forming units counted on plates of Yersinia enterocolitica grown under different conditions of pH, temperature and CO 2 (time-constant conditions for each culture). For both sets, curves were selected to provide a wide variety of shapes with different growth rates and lag times. Statistical criteria used to evaluate model performance were analysis of residuals (residual distribution, bias factor and serial correlation) and goodness-of-fit (residual mean square, accuracy factor, extra residual variance F-test, and Akaike's information criterion). The models showing the best overall performance were the Baranyi, three-phase linear, Richards and Weibull models. The goodness-of-fit attained with other models can be considered acceptable, but not as good as that reached with the best four models. Overall, the Baranyi model showed the best behaviour for the growth curves studied according to a variety of criteria. The Richards model was the best-fitting optical density data, whereas the three-phase linear showed some limitations when fitting these curves, despite its consistent performance when fitting plate counts. Our results indicate that the common use of the Gompertz model to describe microbial growth should be reconsidered critically, as the Baranyi, three-phase linear, Richards and Weibull models showed a significantly superior ability to fit experimental data than the extensively used Gompertz.

Performance characteristics of the immunoglobulin G-capture BED-enzyme immunoassay, an assay to detect recent human immunodeficiency virus type 1 seroconversion.

Recently, we developed an immunoglobulin G (IgG)-capture BED-enzyme immunoassay (BED-CEIA) to identify recent human immunodeficiency virus (HIV) type 1 (HIV-1) seroconversion for use in incidence estimates. We have established an algorithm for its use; developed quality control reagents to monitor the assay; and evaluated its performance for interrun, intrarun, and operator variability. Analysis of 144 individual plates, which involved multiple plate lots and several operators over more than a year, indicated that the coefficients of variation (CVs) were between 10 and 15% for raw optical density (OD) values in the dynamic range between 0.5 and 2.0 OD units; the CVs decreased to 5 to 10% when the OD was normalized (OD-n; OD-n = specimen OD/calibrator OD). The intrarun CVs were generally in the range of 5 to 10% for specimens with ODs <0.5 and less than 5% for specimens with ODs >0.5. The level of concordance between multiple plate lots (n = 6) and multiple operators (n = 7) was quite high (R(2) > 0.9). Comparison of the results of the initial and the confirmatory tests with specimens with OD-n values </=1.5 demonstrated a high degree of correlation (R(2) = 0.92); 566 (92%) of 615 of specimens tested in the two modes retained the same classification (recent or long-term infection). The values for those specimens with changed classifications (n = 49) were close to the cutoff (OD-n = 1.0), as expected. The twofold difference in the HIV IgG contents between the controls and the calibrator reagents was exploited to monitor individual plate runs by using a control plot, which was incorporated into the spreadsheet for data entry and run monitoring. This information provides baseline data for the successful transfer of BED-CEIA to other laboratories and the use of BED-CEIA for the detection of recent HIV seroconversion and the calculation of incidence estimates worldwide.

Cytomegalovirus, Epstein-Barr virus and risk of breast cancer before age 40 years: a case-control study.

We investigated whether there is an association between cytomegalovirus (CMV) and Epstein–Barr virus (EBV) IgG levels and risk of breast cancer before age 40 years. CMV and EBV IgG levels were measured in stored plasma from 208 women with breast cancer and 169 controls who participated in the Australian Breast Cancer Family Study (ABCFS), a population-based case–control study. CMV and EBV IgG values were measured in units of optical density (OD). Cases and controls did not differ in seropositivity for CMV (59 and 57% respectively; P=0.8) or EBV (97 and 96% respectively; P=0.7). In seropositive women, mean IgG values were higher in cases than controls for CMV (1.20 vs 0.98 OD, P=0.005) but not for EBV (2.65 vs 2.57 OD, P=0.5). The adjusted odds ratios per OD unit were 1.46 (95% CI 1.06–2.03) for CMV IgG and 1.11 (0.93–1.33) for EBV IgG. The higher mean CMV IgG levels found in women with breast cancer could be the result of a more recent infection with CMV, and may mean that late exposure to CMV is a risk factor for breast cancer.

Expression of the 60 kDa and 71 kDa heat shock proteins and presence of antibodies against the 71 kDa heat shock protein in pediatric patients with immune thrombocytopenic purpura.

BackgroundImmune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by platelet destruction resulting from autoantibodies against platelet proteins, particularly platelet glycoprotein IIb/IIIa. Heat shock proteins (Hsp) have been shown to be major antigenic determinants in some autoimmune diseases. Antibodies to Hsps have also been reported to be associated with a number of pathological states.MethodsUsing western blot, we measured the levels of the 60 kDa heat shock protein (Hsp60) and of the inducible 71 kDa member of the Hsp70 family (Hsp71) in lymphocytes and the presence of antibodies against these hsps in plasma of 29 pediatric patients with ITP before the treatment and in 6 other patients before and after treatment.ResultsInterestingly only one out of 29 patients showed detectable Hsp60 in lymphocytes while this heat shock protein was detected in the 30 control children. Hsp71 levels were slightly lower in lymphocytes of patients with ITP than in controls (1567.8 ± 753.2 via 1763.2 ± 641.8 integrated optical density (IOD) units). There was a small increase of Hsp71 after recovery from ITP. The titers of plasma antibodies against Hsp60 and Hsp71 were also examined. Antibodies against Hsp71 were more common in ITP patients (15/29) than in control children (5/30). The titer of anti-Hsp71 was also higher in children patients with ITP. The prevalence of ITP children with antibodies against Hsp71 (51.7%) was as high as those with antibodies against platelet membrane glycoproteins (58.3%).ConclusionsIn summary, pediatric patients with ITP showed no detectable expression of Hsp60 in lymphocytes and a high prevalence of antibody against Hsp71 in plasma. These changes add to our understanding of the pathogenesis of ITP and may be important for the diagnosis, prognosis and treatment of ITP.

Estimation of deoxynivalenol (DON) content by symptom rating and exoantigen content for resistance selection in wheat and triticale

Fusarium head blight (FHB) in wheat and triticale leads to contamination of the grain with the mycotoxin deoxynivalenol (DON) that is harmful to animal and man. A fast, low-cost, and reliable method for quantification of the DON content in the grain is essential for selection. We analysed 113 wheat and 55 triticale genotypes for their symptom development on spikes, Fusarium exoantigen (ExAg) and DON content in the grain after artificial inoculation with a highly aggressive isolate of F. culmorum in three (wheat) and six (triticale) location-by-year combinations. Additionally, in triticale the amount of Fusarium damaged kernels (FDK) was assessed. ExAg content was analysed by a newly developed Fusarium-specific plate-trapped antigen enzyme-linked immunosorbent assay (PTA-ELISA) and DON content by an immunoassay. A moderate disease severity resulted in an ExAg content of 0.87 optical density (OD) units in wheat and 1.02 OD in triticale. DON content ranged from 12.0 to 105.2 mg kg−1 in wheat and from 24.2 to 74.0 mg kg−1 in triticale. Genotypic and genotype-by-environment interaction variances were significant (P < 0.01). Coefficient of phenotypic correlation between DON content analysed by the immunoassay and ExAg content was r = 0.86 for wheat and r = 0.60 for triticale. The highest correlation between DON content and symptom rating was found by FHB rating in wheat (r = 0.77) and by FDK rating in triticale (r = 0.71). In conclusion, selection for reduced FHB symptoms should lead to a correlated selection response in low fungal biomass and low DON content in the grain.

Evaluación comparativa del método inmunoenzimático indirecto en leche para la detección de bovinos infectados con Brucella abortus, en hatos del departamento de Cundinamarca, Colombia

To perform a comparative evaluation of the indirect enzyme-linked immunosorbent assay (iELISA) in milk, for the detection of Brucella abortus in cattle, 1,523 milk samples were taken from individual animals and bulk milk belonging to 200 herds in the province of Cundinamarca, Colombia. All these herds were part of the official programme of monitoring free herds and determining herd prevalence in the province. The samples were submitted simultaneously to the milk ring test and the iELISA. A total of 584 individual and 497 bulk milk samples taken from free herds were considered negative, and served to determine the initial ELISA cut-off point. An optimised determination of the cut-off point involved an operational analysis, using a statistical programme. In the analysis, the total population was considered: 756 individual positive and negative samples, as defined by herd history and previously established serologies. The cut-off point was set at > 0.20 optical density units, which, expressed in percentage positivity, corresponded to 20.5% against the controls, with a sensitivity of 95.3%, a specificity of 95.1%, and a confidence interval of 95%. Indirect confirmation of the state of infection was made with competitive ELISA in the serum of the individual animals considered positive, and an attempt was made to determine bacterial presence by isolation in culture and by reverse transcription-polymerase chain reaction. The results confirm that the indirect ELISA is highly sensitive and specific, provides confirmed results in strict quality-control conditions, and may be used to test a large number of herd or individual samples, thus enhancing the efficiency of surveillance programmes and control campaigns.

Optimized serodiagnosis of sheep fascioliasis by Fast-D protein liquid chromatography fractionation of Fasciola hepatica excretory-secretory antigens.

Current methods for the serodiagnosis of sheep fascioliasis show suboptimal sensitivity, specificity, or both. With the aim of developing an improved method, we fractionated native Fasciola hepatica excretory-secretory antigens (ESAs) by size-exclusion FPLC (fast protein liquid chromatography) on a Superdex 75 HR 10/30 column and then tested the serodiagnostic value of the antigens contained in each one of the 4 peaks obtained (peaks I-IV). Serodiagnostic value was assessed using sera from sheep naturally infected with F. hepatica (group A); sera from the individuals of a fluke-free herd (most of which also had other intestinal nematodes, lung nematodes, Moniezia spp., and/or Cysticercus tenuicollis) sera from a fluke-free herd (group B); sera from lambs experimentally infected with 10-40 F. hepatica metacercariae (group C); and sera from uninfected control lambs (group D). Enzyme-linked immunosorbent assay (ELISA) with peak I or II as target antigens (and to a lesser extent with peak III as target) showed reactivity with negative sera, so that it was not possible to establish cutoff values discriminating infected and uninfected animals. In contrast, when peak IV was used as target, a low cutoff value of 0.235 optical density units (mean + 4 SD) discriminated infected and uninfected animals, with 100% sensitivity and 100% specificity. ELISA with peak IV as a target identified infected animals (even animals that had received only 10 metacercariae) within 3-5 wk of infection and subsequently throughout the rest of the 14-wk monitoring period. In Western blotting analysis, again only the antigens contained in peak IV (range 7-40 kDa, under reducing conditions) were specific for diagnosis of infected animals. These results indicate that molecular sieving of F. hepatica ESAs by this procedure is a fast, simple, reproducible way of obtaining antigens useful for serodiagnosis of sheep fascioliasis.

Preeclampsia is associated with increased susceptibility of serum lipids to copper-induced peroxidation in vitro.

Several reports suggest preeclampsia to be associated with oxidative stress. In view of potential experimental artifacts in these studies, we tested the effect of preeclampsia on the oxidizibility of maternal serum lipids, using an optimized ex vivo method. This prospective study included 28 pregnant women with preeclampsia and 28 women matched for maternal and gestational age with normal pregnancies. Venous blood was drawn from the consenting women. Serum levels of lipid peroxidation products and the kinetics of copper-induced oxidation ex vivo were monitored spectroscopically by continuous recording of absorbance at 245 nm. The initial optical density (OD) at 245 nm, attributed to preformed products of lipid peroxidation, was higher in the women with preeclampsia than in the controls (1.26 +/- 0.02 vs. 1.17 +/- 0.02 OD units; p = 0.01). The lag phase preceding oxidation, reflecting resistance of serum lipids to oxidation, was significantly shorter in the preeclampsia group than in the controls (47.4 +/- 2.3 vs. 57.6 +/- 4.0 min; p = 0.027). High levels of serum hydroperoxides and increased susceptibility of serum lipids to copper-induced peroxidation ex vivo indicate preeclampsia to be associated with high oxidative stress. The role of this high oxidizibility in the pathogenesis of preeclampsia has yet to be evaluated.

Efeito antimicrobiano de extrato cítrico sobre Ralstonia solanacearum e Xanthomonas axonopodis pv. manihotis

The widespread application of agrotoxics to control crop diseases has caused human and environmental contamination problems and also a selection of resistant pathogens to these chemical products. Thus, the aim of this work was, by means of citric extract, (Ecolife40 commercial product), to assess the antibacterial activity. The effect of concentrations of 1, 10, 100, 1000 and 5000 ppm of citric extract was carried out on bacteria Ralstonia solanacearum and Xanthomonas axonopodis pv. manihotis through observation of the following parameters: inhibition zone, optical density and colony-forming units. Through the obtained results, it was verified that citric extract showed antibacterial activities. The antibacterial activity was dosis-dependent, and it is more efficient at 5000 ppm.

Preeclampsia is associated with increased susceptibility of serum lipids to copper-induced peroxidation in vitro

Background. Several reports suggest preeclampsia to be associated with oxidative stress. In view of potential experimental artifacts in these studies, we tested the effect of preeclampsia on the oxidizibility of maternal serum lipids, using an optimized ex vivo method. Methods. This prospective study included 28 pregnant women with preeclampsia and 28 women matched for maternal and gestational age with normal pregnancies. Venous blood was drawn from the consenting women. Serum levels of lipid peroxidation products and the kinetics of copper-induced oxidation ex vivo were monitored spectroscopically by continuous recording of absorbance at 245 nm. Results. The initial optical density (OD) at 245 nm, attributed to preformed products of lipid peroxidation, was higher in the women with preeclampsia than in the controls (1.26 ± 0.02 vs. 1.17 ± 0.02 OD units; p = 0.01). The lag phase preceding oxidation, reflecting resistance of serum lipids to oxidation, was significantly shorter in the preeclampsia group than in the controls (47.4 ± 2.3 vs. 57.6 ± 4.0 min; p = 0.027). Conclusions. High levels of serum hydroperoxides and increased susceptibility of serum lipids to copper-induced peroxidation ex vivo indicate preeclampsia to be associated with high oxidative stress. The role of this high oxidizibility in the pathogenesis of preeclampsia has yet to be evaluated.

Inmunodiagnóstico de las infecciones por Strongyloides stercoralis en Chile utilizando la prueba de ELISA

Strongyloides stercoralis is a world wide distributed small intestinal nematode parasite. In immunocompetent individuals S stercoralis can produce asymptomatic infections or a moderate clinical picture of diarrhea, some cases become chronic. In immunocompromised patients, a disseminated disease may appear, sometimes fatal. In Chile, there is little epidemiological information about S stercoralis infections and appropriate diagnostic techniques are usually not used. To evaluate the yield of an ELISA test for the diagnosis of strongyloidiasis in Chilean patients. Ten serum samples from patients with S stercoralis infections confirmed by a positive stool examination, 66 samples from individuals with other infections by tissue helminthes (24 toxocariasis, 15 trichinellosis, 11 hydatidosis, 12 fascioliasis and 4 cysticercosis), 13 samples from subjects with autoimmune diseases and 49 samples from apparently healthy individuals with a normal eosinophil count, were studied. ELISA antigen was prepared using a filariform larval extract obtained from a murine species of Strongyloides, maintained in laboratory animals. Using 0.33 optical density units as a cut off value, 9 of 10 sera of S stercoralis infected individuals, had a positive ELISA test. No cross reactions were observed with sera of patients with other helminthic infections, autoimmune diseases or in healthy individuals. Thus, specificity, positive and negative predictive values were 100%. The results obtained are similar with those found by other investigators. ELISA test for strongyloidiasis is a useful tool for the diagnosis of clinical cases and for seroepidemiological studies of this nematode infection in Chile.

Regulation of insulin-like growth factor binding protein-6 expression in the reproductive tract throughout the estrous cycle and during the development of the placenta in the ewe.

Insulin-like growth factors (IGF-I and IGF-II) are essential for normal uterine development and have been particularly implicated in fetal and placental growth. A family of six IGF binding proteins enhance or attenuate IGF-stimulated cell proliferation. In this study we have used in situ hybridization to map the distribution of IGFBP-6, one of the lesser known of the IGFBPs, in sections of the uterus collected from cyclic, anestrous, and ovariectomized nonpregnant ewes and from the uterus and placenta of early pregnant (13-55 days) and unilaterally pregnant ewes. In nonpregnant ewes IGFBP-6 mRNA (measured as arbitrary optical density units from autoradiographs) was abundant in the periepithelium and caruncles, with lower levels in the endometrial stroma and myometrium. In most regions IGFBP-6 mRNA showed cyclic variations with concentrations maximal around ovulation and the early luteal phase. In addition, 16 out of 25 ewes expressed IGFBP-6 mRNA in their endometrial glands between estrus and Day 2. Measurements of IGFBP-6 mRNA were high in anestrous ewes (equivalent values to ovulation) but low in ovariectomized ewes (equivalent values to mid to late luteal phase). In pregnant ewes IGFBP-6 mRNA was found in similar regions to those recorded during the cycle. In the periepithelium and caruncular stroma IGFBP-6 mRNA levels were higher during early pregnancy than in the midluteal phase. In the unilateral pregnant ewes there was no difference in IGFBP-6 mRNA measured between pregnant and nonpregnant horns. In conclusion, IGFBP-6 mRNA is differentially regulated during the estrous cycle and pregnancy and may be functionally important in modulating IGF activity in the uterus and placenta by virtue of its strong affinity and ability to regulate IGF-II mediated actions.

Serum immunoglobulin G antibodies to chlamydial heat shock protein 60 but not to human and bacterial homologs are associated with coronary artery disease.

Evidence for an association between Chlamydia pneumoniae infection and coronary artery disease (CAD) has been reported by numerous studies, cross-reactive heat shock protein (Hsp) antibody responses have been causally linked to CAD, and the severity of chlamydial disease pathogenesis correlates with Hsp serology. Our aim was to determine if chlamydial Hsp (cHsp) antibody responses are predictive of CAD. Patients were recruited in a case-control study: 250 cases had angiographically significant CAD (stenosis > or =70%), and 250 controls had normal coronary arteries (stenosis <10%). Serum immunoglobulin G reactivity to Hsp10 and Hsp60 antigens (chlamydial, Escherichia coli, and human), and C pneumoniae whole organisms were measured by ELISA. Univariate analysis confirmed that classical CAD risk factors were predictors of CAD. Univariate analysis showed that cHsp60 (P= 0.001, OR 3.9), cHsp10 (P=0.045, OR 3.8), E coli Hsp60 (P=0.04, OR 1.5) and C pneumoniae (P=0.03, OR 1.8) ELISA optical density (OD) values were significantly different between cases and controls. Multivariate analysis found that only upper-quintile cHsp60 seroreactivity remained a significant predictor of CAD after controlling for classical CAD risk factors and seroreactivity to the other antigens (cHsp60 OD, P=0.005, OR 3.9 per OD unit; cHsp60 quintile, 5 versus 1 to 4; P=0.01, OR 2.1). The presence of elevated anti-cHsp60 immunoglobulin G antibodies, but not anti-human or anti-E coli homologs, was independently associated with CAD. This finding argues against previous suggestions that cross-reactive or autoimmune Hsp60 responses may contribute to disease progression. High anti-cHsp60 antibody response appears to identify the subset of patients with chlamydial infection and significant CAD.

Distribution and quantification of NMDA R1 mRNA and protein in the piglet brainstem and effects of intermittent hypercapnic hypoxia (IHH)

The first aim of this study was to determine the cellular distribution of NR1 in the piglet brainstem. Documentation of NR1 mRNA was by non-radioactive in situ hybridisation (non-RISH) and of NR1 protein by immunohistochemistry. We found that all neurons expressed mRNA but not all had NR1 protein. Application of non-RISH has permitted us, for the first time, to document the cellular localization of NR1 mRNA showing that it was present in the cytoplasm and nucleolus of motor neurons but dispersed throughout the cellular compartments of sensory neurons. NR1 protein on the other hand, was localized to the cytoplasm only. The second aim of this study was to quantify the distribution of NR1 mRNA and protein. Using image analysis software, we used optical density (OD) to quantify the non-RISH signal for mRNA and cellular counting for protein (expressed as % positive). Results show that NR1 expression is greater in motor than sensory nuclei; for mRNA: 0.46±0.04 vs. 0.31±0.02 OD units ( P<0.001), for protein: 75.9±3.1 vs. 58.4±2.5% positive ( P<0.001). The third aim of this study was to determine the effects of intermittent hypercapnic hypoxia (IHH) on NR1 expression. Chronic IHH exposure caused differential changes in mRNA and protein expression. NR1 mRNA expression increased while the number of neurons expressing NR1 protein showed no change. This finding suggests that NMDA pathways are activated by exposure to IHH.