Characterization of transforming growth factors beta1 and 2 in ferrets (Mustela putorius furo).

Unwanted scar tissue after surgical procedures remains a central problem in medicine. Nowhere is this problem more evident than within the pediatric airway, where excess scarring, termed subglottic stenosis, can compromise breathing. Recent advances in molecular biology have focused on ways to decrease scar formation through understanding of the wound repair process. Transforming growth factor beta (TFGbeta) plays a central role in this pathway. Ferrets serve as an ideal model for the pediatric airway, and reproduction of subglottic stenosis in ferrets is possible. However, ferret cytokine profiles have not been established. In this study, we characterized the presence and nucleotide sequence of the TGFbeta1 and 2 genes in ferrets by using total RNA isolated from airways. Amino acid sequence homology between human and ferret was determined to be 96.6% for TGFbeta1 and 99.3% for TGFbeta2. Given the nearly total homology between TGFbetas of ferret and human origin, the ferret may serve as an ideal model for future molecular studies.

Gender differences in the blood volume of conscious Sprague-Dawley rats.

Reference values of blood volume (BV) and plasma volume (PV) of animal species are given as functions of body weight and gender specification generally is not given. Considering the common observation of a decreased hematocrit (Hct) in the females of many species, the BV, the PV, or both must differ between genders. The present study was performed to determine the magnitude of those differences. We measured Hct and PV in 24 female and 23 male Sprague-Dawley rats in their 12th week of life. The rats were surgically prepared with indwelling femoral arterial catheters 4 d prior to the determination of BV. Evan's Blue dye dilution was used to determine PV in conscious, quietly resting animals. BV was calculated as PV/(1-Hct). Mean Hct was 2% lower in female rats than males, and PV (mean +/- 1 standard deviation) was 4.86 +/- 0.54 ml/100 g in females compared with 4.12 +/- 0.32 ml/100 g in males. Calculated BV in female rats was 7.84 +/- 0.70 ml/100 g compared with 6.86 +/- 0.53 ml/100 g in males. When precise estimates of BV or PV are needed for research or dosing purposes, gender differences of 18% for PV and 14% for BV must be considered. In addition, species other than the rat may have similar discrepancies between sexes, and the prudent investigator must determine individual volume assessments of both sexes before assumptions of BV and PV for a species can be made.

Effects of prenatal ethanol exposure and sex on the arginine vasopressin response to hemorrhage in the rat.

AVP synthesis, storage, and osmotically stimulated release are reduced in young adult rats exposed prenatally to ethanol (PE). Whether the reduced release of AVP to the osmotic stimulus is due to impairment of the vasopressin system or specifically to an osmoreceptor-mediated release is not known. The present experiments were done, therefore, to determine whether a hemorrhage-induced AVP response would also be diminished in PE-exposed rats. Pregnant rats were fed either a control liquid diet [no prenatal ethanol (NPE)] or a liquid diet with 35% of the calories from ethanol from days 7-21 of pregnancy. Offspring were weaned at 3 wk of life. At 11 wk of age, femoral arterial catheters were surgically placed, and blood volumes were determined at 12 wk. Three days later, two hemorrhages of 10% of the blood volume were performed with samples taken before and 10 min after the hemorrhages. After a 20% blood loss, plasma AVP was 19% higher in NPE rats than in the PE rats despite no differences in mean arterial blood pressure (MABP). Also, hypothalamic AVP mRNA and pituitary AVP content were reduced in PE rats. Furthermore, confirming an earlier report of sex differences in AVP release, the hemorrhage-induced hormone response was twofold greater in female rats than male rats, regardless of previous ethanol exposure. These studies demonstrate that the AVP response to hemorrhage is reduced in PE rats independently of differences in MABP. The data are compatible with a theory of a reduced number of hemorrhage-responsive vasopressinergic neurons capable of stimulated AVP release in PE rats.

Prenatal exposure to ethanol causes partial diabetes insipidus in adult rats.

Chronic consumption of ethanol in adult rats and humans leads to reduced AVP-producing neurons, and prenatal ethanol (PE) exposure has been reported to cause changes in the morphology of AVP-producing cells in the suprachiasmatic nucleus of young rats. The present studies further characterize the effects of PE exposure on AVP in the young adult rat, its hypothalamic synthesis, pituitary storage, and osmotically stimulated release. Pregnant rats were fed a liquid diet with 35% of the calories from ethanol or a control liquid diet for days 7-22 of pregnancy. Water consumption and urine excretion rate were measured in the offspring at 60-68 days of age. Subsequently, the offspring were infused with 5% NaCl at 0.05 ml.kg(-1).min(-1) with plasma samples taken before and at three 40-min intervals during infusion for measurement of AVP and osmolality. Urine output and water intake were approximately 20% greater in PE-exposed rats than in rats with no PE exposure, and female rats had a greater water intake than males. The relationship between plasma osmolality and AVP in PE-exposed rats was parallel to, but shifted to the right of, the control rats, indicating an increase in osmotic threshold for AVP release. Pituitary AVP was reduced by 13% and hypothalamic AVP mRNA content was reduced by 35% in PE-exposed rats. Our data suggest that PE exposure can cause a permanent condition of a mild partial central diabetes insipidus.

Effects of FiO2 on O2 consumption and cardiovascular and hormonal responses to hemorrhage in the goat.

This study was conducted to determine whether 100% FiO2 during hemorrhage would improve maintenance of mean arterial blood pressure and to assess the cardiovascular, arginine vasopressin, and renin-angiotensin system roles in the response. This also allowed evaluation of FiO2 effects on the baroreceptor control of these hormone systems. Six conscious female goats were hemorrhaged (0.5 mL x kg(-1) x min(-1)) for 30 minutes, while breathing 11%, 21%, or 100% O2. Mean arterial blood pressure was maintained only when the goats breathed 100% O2. FiO2 did not affect O2 consumption or delivery during hemorrhage. Increases in renin and arginine vasopressin were equal or reduced with 100% FiO2 and therefore did not contribute to the improved mean arterial blood pressure maintenance. Inspiration of 100% FiO2 during hemorrhage, therefore, may improve perfusion pressure with no changes in O2 consumption or delivery. Also, 100% FiO2 eliminated the negative correlation between both hormones and right atrial pressure, suggesting altered baroreceptor control of the hormones.