The UV filter benzophenone 3, alters early follicular assembly in rat whole ovary cultures.

Our goal was to study the effect of BP3 (benzophenone 3) in the follicular assembly and the potential involvement of Foxl2 pathway using whole ovary cultures. Ovaries were collected from Wistar rats at birth, treated in vitro with vehicle (0.01% DMSO), BP3 (5.8 nM, 276 nM, 576 nM and 876 nM) or ESR2 inhibitor (0.1 nM), and cultured for 7 days. Nest breakdown, follicular assembly and the expression of several regulators of these processes (p27, Foxl2, Sox9, Bmp2, Cyp19 and Fst) were evaluated. In vitro exposure to BP3 (5.8 nM) decreased the population of total oocytes, the number of nests per ovary and early primary follicles population. In addition, BP3 (5.8 nM) induced overexpression of Foxl2 mRNA levels through ESR2 but increased Fst mRNA levels independently from ESR2 or Foxl2. We also observed that the number of p27-positive oocytes was decreased after BP3 (5.8 nM). On the other hand, exposure to BP3-276 increased total oocytes, the number of nests per ovary and decreased primary follicles. In addition, BP3-276 induced no changes of Foxl2 mRNA levels through ESR2 but increased Fst mRNA levels independently from ESR2 or Foxl2. In conclusion, our study clearly shows that exposure to BP3 is to perturb the early events of germ cell development as showed here in whole ovary cultures.

Correction to: The effect of acute vs chronic magnesium supplementation on exercise and recovery on resistance exercise, blood pressure and total peripheral resistance on normotensive adults.

The original article [1] contains an error whereby the datum value of '17.7%' in both the Abstract and the first line of the Bench press sub-section of the Results section is incorrect.

Effect of magnesium supplementation on blood pressure: a meta-analysis.

To date, there has been inconclusive evidence regarding the effect of magnesium supplements on blood pressure (BP). This meta-analysis was conducted to assess the effect of magnesium supplementation on BP and to establish the characteristics of trials showing the largest effect size. Primary outcome measures were systolic blood pressure (SBP) and diastolic blood pressure (DBP) at the end of the follow-up period. One hundred and forty-one papers were identified, of which 22 trials with 23 sets of data (n=1173), with 3 to 24 weeks of follow-up met the inclusion criteria, with a supplemented elemental magnesium range of 120-973 mg (mean dose 410 mg). 95% confidence intervals (CI) were calculated using DerSimonian and Laird's random-effects model, with effect size calculated using Hedges G. Combining all data, an overall effect of 0.36 and 0.32 for DBP and SBP, respectively, was observed (95% CI 0.27-0.44 for DBP and 0.23-0.41 for SBP), with a greater effect being seen for the intervention in crossover trials (DBP 0.47, SBP 0.51). Effect size increased in line with increased dosage. Although not all individual trials showed significance in BP reduction, combining all trials did show a decrease in SBP of 3-4 mm Hg and DBP of 2-3 mm Hg, which further increased with crossover designed trials and intake >370 mg/day. To conclude, magnesium supplementation appears to achieve a small but clinically significant reduction in BP, an effect worthy of future prospective large randomised trials using solid methodology.

Collagen remodelling in the guinea-pig uterine cervix at term is associated with a decrease in progesterone receptor expression.

In human and guinea-pig parturition, progesterone withdrawal and estrogen action are not mediated by changes in their circulating levels. Instead, these events might be promoted by changes in the responsiveness of the uterus and cervix to progesterone and estrogen via changes in their receptors. In this study, the guinea-pig model was used to investigate whether high levels of progesterone and estrogen at term are associated with regional changes in PR and ERalpha levels in uterus and cervix. PR and ERalpha profiles were established in both subepithelium and the muscular layer of the cervix and the lower uterine horns during pregnancy, parturition and postpartum; while collagen remodelling was measured in the subepithelium. Our data showed that collagen remodelling involved in cervical ripening is temporally and spatially associated with a decrease in PR, whereas high expression of ERalpha is observed. This association was found in the subepithelium of the cervical tissue but not in the same region of the uterus. The muscular region of the cervix and uterus also present a transiently decreased expression of PR while ERalpha levels remain high. Thus, the present results indicate that, before parturition, diminished responsiveness of the cervix to progesterone might be caused by a decrease in PR levels and that this may be the mechanism of functional progesterone withdrawal. The guinea-pig was further validated as an animal model for human parturition studies.

A new stain for identification of avian leukocytes.

Differential staining of avian leukocytes was achieved within 6 min following brief fixation in a methanolic solution of C.I. acid red 360 followed by immersion in a mixture containing C.I. basic blue 41, C.I. basic blue 141, and C.I. acid red 52. Heterophils contained black angular and punctate granules. Eosinophils contained bright purple granules. Lymphocytes displayed red nuclei and blue cytoplasm. Monocytes contained red-brown nuclei and lavender cytoplasm. Basophils showed red-orange granules. Thrombocytes stained deep purple. Compared to traditional panoptic stains like Wright's or Giemsa's, the new staining method provides brighter colors, more precise details of cellular structures, and shorter staining time. Significantly, it facilitates identification of avian leukocyte species based on differences in color as well as differences in size and shape.

Perivascular plasmacytosis: a light-microscopic and immunohistochemical study of 93 bone marrow biopsies.

In bone marrow biopsies from 13 hematologically normal persons and from 80 patients with a variety of disorders, we found perivascular plasmacytosis. In all instances except the one case of multiple myeloma, plasma cells were polyclonal and normal in morphology. This was especially pronounced in patients with HIV infection, and in individuals following chemotherapy. In the same patients, sinusoids were also prominent, and appeared dilated. In biopsy sections, small endothelial-lined vessels appeared to arise from attenuation of the sinusoidal lumen. After a short segment of only endothelial-lined vessels, perivascular plasmacytosis appeared. When smooth muscle cells began to line the endothelium, plasma cells virtually disappeared. The biological significance of this finding is unknown. Possibly, the close proximity of plasma cells to endothelial cells early in the development of blood vessels could facilitate entry of immunoglobulins into the blood.

Chronic hypoxia modulates diaphragm function in the developing rat.

We studied the effect of chronic hypoxia on contractile properties and neuromuscular transmission in the developing rat diaphragm. We hypothesized that chronic hypoxia delays maturation of neuromuscular transmission. Phrenic nerve hemidiaphragm preparations were harvested from 3- to 26-day-old rats and littermates raised in 9.5% oxygen. Specific force, contraction time, and one-half relaxation time were measured. Each diaphragm was stimulated directly or via its nerve with 1-s trains at 10-100 Hz. Contraction time and one-half relaxation time decreased with advancing age in both groups, with a greater rate of decrease in hypoxic diaphragms. Specific force was lower for hypoxic diaphragms compared with controls. Diaphragms from the 3- to 10-day-old control and hypoxic groups generated less force in response to stimulation at frequencies >40 Hz but did so to a greater degree with nerve stimulation. Nerve stimulation of diaphragms from 11- to 18-day-old hypoxic rats showed a greater decrease in force with increasing frequency compared with age-matched controls. Diaphragms from 19- to 26-day-old rats showed no difference between the hypoxic and control groups. We conclude that chronic hypoxia leads to diaphragms that generate lower specific force as well as to a delayed maturation of mechanisms involved in neuromuscular transmission.

Relaxin has a minor role in rat mammary gland growth and differentiation during pregnancy.

Growth and differentiation of mammary gland is associated with numerous hormones and a variety of cell-cell, cell-matrix interactions. This study addressed the role of relaxin (Rlx) on these processes. Morphologic and biochemical changes that occur throughout the second half of pregnancy are reported. Temporal patterns and spatial distributions of markers useful to evaluate proliferation, secretion, and collagen remodeling were established. To evaluate the role of Rlx, an ablation/replacement animal model was used. Considering Rlx secretion pattern, two periods were selected: d 11 through d 13, and d 20 through d 23. In the stroma, the extracellular compartment showed changes associated with the lack of Rlx. Collagen remodeling within the lobuloalveolar structure, measured by a significant increase in collagen birefringence, decreased at d 12, d 21, and d 22. Parenchymal structures were less sensitive to the absence of Rlx than stroma. Epithelial cell proliferation was lower in Rlx-deficient rats only at d 12, and alpha-lactalbumin expression decreased at d 21 and d 22. Both lobuloalveolar diameter and percentage of area occupied by these structures showed no changes. In the absence of Rlx, some of the studied markers showed statistically significant differences in scattered days; these do not make clear trends. No differences were found on d 23 on any of the studied parameters suggesting that compensatory mechanisms might be activated to overcome the effects of the absence of Rlx. Unlike the critical role of Rlx either in uterine cervix dilation or in nipple development during rat pregnancy, Rlx had a minor role in growth and differentiation of rat mammary gland.

Sex-dependent components of the analgesia produced by athletic competition.

Competing in various athletic events (track meet, basketball game, or fencing match) can produce analgesia to cold pressor stimuli in male and female college athletes compared with baseline assessments. This competition-induced analgesia has been attributed to the stress associated with competition, which has components related to both physical exercise and the cognitive aspects of competing. This study evaluated the analgesic effect of exercise-related stress, and that caused by the cognitively stressful components of competing independent of exercise. Cold pressor pain ratings were assessed after competition in a track meet and after treadmill exercise or sedentary video game competition in both athletes and nonathletes. As expected, competing in athletics resulted in a decrease in cold pressor ratings in both male and female athletes. Independent of athletic status, treadmill running induced analgesia in women, but not in males, whereas sedentary video game competition produced analgesia in men, but not in women. These findings suggest that different components of the competitive athletic experience might be responsible for the analgesic effects in a sex-dependent manner.

Detection of bromodeoxyuridine in formalin-fixed tissue. DNA denaturation following microwave or enzymatic digestion pretreatment is required.

The present study was designed to assess the influence of antigen retrieval and/or DNA denaturation on the quantitative estimation of bromodeoxyuridine (BrdU) in formalin-fixed paraffin-embedded tissue. Specimens of small intestine from rats injected with BrdU were routinely fixed and embedded in paraffin. For antigen retrieval, sections were pretreated with microwave irradiation or enzymatically (pepsin or trypsin). Acid hydrolysis was used as a DNA denaturation method. Immunostaining of BrdU-labeled cells was performed. The best results, regarding tissue morphology and immunostaining, were obtained with microwave pretreatment followed by acid hydrolysis. Enzymatic pretreatment resulted in damage of tissue morphology and/or high background staining. Microwave alone, without DNA denaturation, resulted in a lower percentage of BrdU positive cells. The significance of validation studies is emphasized when the level of positivity for a prognostic marker, such as BrdU, is assessed.

Estrogen and progesterone modulation of eosinophilic infiltration of the rat uterine cervix.

Ripening of the rat cervix involves widespread collagenolysis that follows an eosinophilic leukocyte infiltration. The hormonal control of these events is not well understood. The aims of this study were to investigate the mechanism through which progesterone (P) and 17beta-estradiol (E(2)) modulate eosinophilic invasion and to determine if this event is protein synthesis mediated. Cervical eosinophilic invasion was measured in intact rats during the second half of pregnancy and compared with values from ovariectomized (O) pseudopregnant (PSP) rats treated with P and E(2) in doses that mimicked the levels of pregnancy. Other O-PSP rats were treated with an E(2) antagonist (tamoxifen) and the antiprogestin RU-486. To study the role of protein synthesis in eosinophilic invasion of the cervix, rats were treated with actinomycin-D (an inhibitor of mRNA synthesis), and animals were sacrificed on D21 or D22 to evaluate eosinophilic invasion. Rats treated with E(2) showed high levels of infiltration and tamoxifen blocked this E(2) effect. On the other hand, P antagonized the stimulatory effects of E(2) on eosinophilic invasion, however when the P and E(2) treated rats were injected with RU-486 the inhibitory effect of P was reversed. In intact pregnant rats a sharp rise in eosinophilic infiltration was detected on D23, 20 h after the fall of serum P. Finally, E(2) treated rats injected with actinomycin-D had no invasion of eosinophils. In conclusion, the estrogen-triggered eosinophil invasion is affected by the classic estrogen receptor antagonist tamoxifen and by the mRNA synthesis blocker actinomycin-D suggesting a genomic action of E(2). Furthermore, the estrogen effect is blocked by P and this inhibition is reversed by RU-486.

Elliptocytes and tailed poikilocytes correlate with severity of iron-deficiency anemia.

This study examines the relationships between abnormal RBC morphology, RBC indices measured with an automated hematology analyzer, serum iron studies, and severity of anemia in patients with findings indicative of iron-deficiency anemia. Counts and morphologic classification of 1,000 RBCs from each of 22 patients were performed, and correlations were determined between parameters. The Student t test was used to determine the level of significance for correlations between parameters. Several significant relationships were found. As the percentage of elliptocytes increased, hemoglobin concentration, hematocrit, RBC concentration, and mean corpuscular hemoglobin level decreased (r = .48, .44, .40, and .49, respectively; P < .05). As the percentage of tailed poikilocytes increased, hemoglobin concentration, hematocrit, and RBC concentration decreased (r = .70, .77, and .71, respectively; P < .01) and RBC distribution width increased (r = .73; P < .01). Of significance, serum ferritin levels, long considered the best single indicator of iron deficiency, showed no correlation with the morphologic abnormalities assessed, severity of anemia, or any of the analyzer-generated indices. Our results indicate that microscopic evaluation of RBC morphology remains an important tool for the pathologist to evaluate the severity of anemia in patients with iron deficiency.

Impact of medical student preceptorship on ED patient throughput time.

A prospective, consecutive study was performed to determine if medical student supervision in the emergency department (ED) changes patient throughput time (ie, the time from triage to discharge). The mean patient throughput time on days when medical students were present in the ED (group 1) was compared to the mean patient throughput time on days when medical students were absent from the ED (group 2). Throughput time was measured in minutes. The mean throughput times of the two groups were compared by the two tailed t test (P < .05). The study had a power of 90% (beta = .10) to detect a throughput time difference of 20 minutes. The two groups were also compared for mean daily acuity (as gauged by mean daily number of patient admissions) and mean daily patient census. The differences in mean daily throughput times (group 1, 145.2 min v group II, 150.6 min; P = .40), mean daily census (group 1, 28.1 patients v group 2, 28.1 patients; P = .75), and mean daily admissions (group 1, 10.4 patients v group 2, 10.7 patients; P = .74) were all insignificant. Precepting medical students in this ED did not significantly change patient throughput times.