Effects of chromium supplementation on physiology, feed intake, and insulin related metabolism in growing pigs subjected to heat stress

Improving insulin sensitivity may reduce impacts of heat stress (HS) in pigs by facilitating heat dissipation. Chromium (Cr) has been reported to improve insulin sensitivity in pigs. Therefore, the aim of this experiment was to investigate whether Cr supplementation can mitigate HS in growing pigs. Thirty-six gilts were randomly assigned to 2 diets containing 0 (control) or 400 ppb Cr. After 14 d the supplemented pigs were allocated to either 8 d thermoneutral (20°C constant; TN) or cyclic HS (35°C, 0900 h to 1700 h) conditions and continued their respective diet (n = 9 per group). Growth performance was recorded during the 14-d supplementation period. The physiological responses to HS were monitored by measuring respiration rate, rectal temperature, blood gas chemistry, and feed intake during thermal exposure. Kinetics of plasma glucose, insulin and NEFA were studied by intravenous glucose tolerance test (IVGTT) on d 8 of thermal treatment. Results showed Cr alleviated the HS-increased rectal temperature (P < 0.05) and respiration rate (P < 0.01) at 1300 h and 1600 h during thermal exposure. However, Cr did not mitigate the reduction in average daily feed intake which was reduced by 35% during HS or the HS-induced respiratory alkalosis. Chromium tended to increase average daily gain (0.86 vs. 0.95 kg, P = 0.070) during the 14-d supplementation under TN conditions before thermal exposure, which might be associated with the potential of Cr in improving overall insulin sensitivity, as evidenced by a reduced insulin resistance index calculated by Homeostatic Model Assessment (HOMA-IR; 0.65 vs. 0.51, P = 0.013) and a tendency of reduced fasting plasma insulin concentration (1.97 vs. 1.67 μU/mL, P = 0.094). Heat stress decreased the acute insulin releasing rate (P = 0.012) and consequently slowed glucose clearance rate (P = 0.035) during IVGTT. Besides, HS enlarged the values of area under the curve of NEFA during IVGTT (P < 0.01), indicating a reduced lipid mobilization. In conclusion, HS reduced insulin response to IVGTT. Chromium supplementation exhibited a potential in improving insulin sensitivity and mitigating HS symptoms in growing pigs.

Selenium and vitamin E together improve intestinal epithelial barrier function and alleviate oxidative stress in heat-stressed pigs

What is the central question of this study? Oxidative stress may play a role in compromising intestinal epithelial barrier integrity in pigs subjected to heat stress, but it is unknown whether an increase of dietary antioxidants (selenium and vitamin E) could alleviate gut leakiness in heat-stressed pigs. What is the main finding and its importance? Levels of dietary selenium (1.0 p.p.m.) and vitamin E (200 IU kg(-1) ) greater than those usually recommended for pigs reduced intestinal leakiness caused by heat stress. This finding suggests that oxidative stress plays a role in compromising intestinal epithelial barrier integrity in heat-stressed pigs and also provides a nutritional strategy for mitigating these effects. Heat stress compromises the intestinal epithelial barrier integrity of mammals through mechanisms that may include oxidative stress. Our objective was to test whether dietary supplementation with antioxidants, selenium (Se) and vitamin E (VE), protects intestinal epithelial barrier integrity in heat-stressed pigs. Female growing pigs (n = 48) were randomly assigned to four diets containing from 0.2 p.p.m. Se and 17 IU kg(-1) VE (control, National Research Council recommended) to 1.0 p.p.m. Se and 200 IU kg(-1) VE for 14 days. Six pigs from each dietary treatment were then exposed to either thermoneutral (20°C) or heat-stress conditions (35°C 09.00-17.00 h and 28°C overnight) for 2 days. Transepithelial electrical resistance and fluorescein isothiocyanate-dextran (4 kDa; FD4) permeability were measured in isolated jejunum and ileum using Ussing chambers. Rectal temperature, respiratory rate and intestinal HSP70 mRNA abundance increased (all P < 0.001), and respiratory alkalosis occurred, suggesting that pigs were heat stressed. Heat stress also increased FD4 permeability and decreased transepithelial electrical resistance (both P < 0.01). These changes were associated with changes indicative of oxidative stress, a decreased glutathione peroxidase (GPX) activity and an increased glutathione disulfide (GSSG)-to-glutathione (GSH) ratio (both P < 0.05). With increasing dosage of Se and VE, GPX-2 mRNA (P = 0.003) and GPX activity (P = 0.049) increased linearly, the GSSG:GSH ratio decreased linearly (P = 0.037), and the impacts of heat stress on intestinal barrier function were reduced (P < 0.05 for both transepithelial electrical resistance and FD4 permeability). In conclusion, in pigs an increase of dietary Se and VE mitigated the impacts of heat stress on intestinal barrier integrity, associated with a reduction in oxidative stress.

Forceps delivery after molar malignancy in a woman with arteriovenous malformation. A case report

BACKGROUND

An arteriovenous (AV) fistula in the female pelvis is a rare finding. This report describes a successful pregnancy after selective embolization of a postmolar vascular malformation.

CASE

At 5 weeks of pregnancy, a 27-year-old, white female, gravida 3, para 0, was discovered on ultrasound examination to have an AV malformation along with a fetal pole. The patient was asymptomatic and had previously received two courses of chemotherapy for a previous nonmetastasized malignant molar pregnancy. Doppler ultrasonography uncovered a vascular malformation extending from the margin of the fetal pole to the margin of the uterus. The pregnancy ended at 8 weeks with a spontaneous abortion. The patient underwent angiography and embolization of extensive right-sided uterine vessels. She resumed normal menstrual periods six weeks after the embolization and became pregnant. The pregnancy concluded in low forceps vaginal delivery of a healthy, female infant at 34 weeks.

CONCLUSION

Vaginal delivery following postmolar pregnancy and a uterine AV malformation may be considered a viable delivery option.

Risk factors for maternal colonization with group B beta-hemolytic streptococci

Colonization with group B beta-hemolytic streptococci (GBS) at any time during pregnancy is an important risk factor for neonatal sepsis. To determine which groups of pregnant women are at high risk for GBS, a retrospective chart review was conducted on 608 pregnant women who had recorded data on prenatal charts and were seen between October 1995 and December 1997 at a family practice-run prenatal clinic. A total of 543 subjects were studied after exclusion of women who had no results of GBS colonization recorded. Demographically, the study population comprised 91.1% white non-Hispanic, 4.8% African-American, 1.5% Asian, and 2.6% white Hispanic women; 28.9% were primiparas, 38.9% unmarried; 60.0% low income; 31.1% smokers, 7.7% with a history of drug or alcohol use; 8.4% with a history of sexually transmitted disease; and 27.2% with fewer than 11 prenatal visits. The mean age was 26.4 years (range, 14 to 42 years). Seventy-six (14.0%) of the study subjects were colonized with GBS. White non-Hispanic women had a GBS colonization prevalence of 13.6%; for all others, prevalence was 18.7%. No statistically significant differences were found in regard to age, weight, number of prenatal visits, income level, marital status, history of drug use, or parity. The GBS colonization rate for smokers was 33.1% versus 16.4% for nonsmokers (P = .012). Maternal colonization of GBS was not found to be associated with any of the risk factors studied, other than smoking. This study identified smoking as a possible risk factor for GBS infection. Routine screening for GBS infection during pregnancy may be beneficial because no strong risk factors for colonization exist.

A review of alternative birthing positions

This article reviews a number of nonevidenced-based studies that have been conducted on the different physical positions of labor and delivery. A review of the literature disclosed that the traditional supine position appeared to be associated with a prolonged second stage of labor and persistence of occiput posterior presentations. However, the supine and left lateral positions are excellent for providing anesthesia and access, although there may be a little added benefit for the parturient's comfort. The sitting, squatting, and hands-and-knees positions offer superior patient participation. The squatting position held for a long time may be physically stressful. The sitting and standing positions are known for occasional excessive hemorrhage and added expense. The hands-and-knees position offers the advantages of the gravitation effect of the upright positions and may be associated with less perineal damage. Overall, there has been no report of any harm to the infant when alternative positions are used.