Inhibition of vascular endothelial growth factor-induced retinal neovascularization by retinoic acid in experimental retinopathy of prematurity

Vascular endothelial growth factor (VEGF) has an important role in the pathogenesis of retinopathy of prematurity (ROP) and inhibition of VEGF expression in the neovascular phase might prevent destructive neovascularization in ROP. It is suggested that retinoids exert a highly potent antiangiogenic activity by inhibiting VEGF expression. The aim of this study was to demonstrate the preventive effect of retinoic acid (RA) on the VEGF-induced retinal neovascularization in a rat model of ROP. Wistar albino rats were placed into incubators at birth and exposed to an atmosphere alternating between 50 % and 10 % O(2) every 24 hours. After 14 days, the animals were removed to room air and received either an intraperitoneal injection of RA (5 mg/kg/day) (n=9) or saline (n=4) daily for six days, and sacrificed at 21 days. Other rats (n=4) were raised in room air and served as age-matched controls. The globe of each eye was cut through the cornea and embedded in paraffin. Serial sections were stained with hematoxylin-eosin for quantification of neovascular nuclei. The avidin-biotin peroxidase method was performed for evaluation of VEGF expression. The average number of neovascular nuclei was significantly lower in the control group compared to that in the ROP groups. In addition, it significantly decreased in the RA-treated ROP group compared to that of the saline-administrated ROP group. VEGF immunostaining was overall negative in room air-exposed rats. The VEGF immunostaining score significantly decreased in the RA-treated ROP group compared to that in the saline-administered ROP group. RA treatment might be beneficial in preventing neovascularization resulting from oxygen-induced retinopathy by downregulation of VEGF expression.     

Evaluating the effect of silver nanoparticles on testes of adult albino rats (histological,immunohistochemical and biochemical study)

Silver nanoparticles (AgNPs) are widely used in medicine, however, they have toxic impacts on different organs. AgNPs distribution to the testes was reported, so, we aimed to study the effect of intraperitoneal injection of AgNPs, at different concentrations and different time durations, on adult rat testes. Sixty healthy adult male Wistar albino rats were divided into three groups; control group (Group I) and two experimental groups (Groups II & III), each of which were subdivided into two subgroups. Rats in group II were exposed for 7 days to low and high doses of AgNPs, respectively. Rats in group III were exposed for 28 days to low and high doses of AgNPs, respectively. Testicular sections were stained with H&E, Toluidine blue, Immunohistochemical staining for Ki-67 and CD68 and Electron microscope examination were performed. Serum testosterone level and Quantitative Real-Time PCR for spermatogenesis genes were measured. Group IIa & IIb showed thickened capsule studded with nanoparticles, congested blood vessels, disorganized seminiferous tubules (Sts) and detached germinal epithelium. Group IIIa & IIIb showed marked reduction in the germinal epithelium, and shrunken Sts with the absence of sperms in most of them, which was more evident with higher doses of AgNPs. Significant decrease in cell proliferation and increase in interstitial tissue macrophages were more detected in groups II & III than in the control group. Decreased serum testosterone and decreased expression levels of spermatogenesis genes in groups IIa, IIb & IIIa, IIIb than in the control group were observed. In conclusion: intraperitoneal injection of AgNPs adversely affected the structure of adult rat testes. The tissue damage was more manifested with increased dose and duration of exposure.     

Reloading of rat soleus after hindlimb unloading and serum insulin-like growth factor 1

The aim of this study was to elucidate the effects of 14- day hindlimb suspension (HS) and subsqquent reloading (3 or 7 days) on the m. soleus mass, muscle fiber cross-sectional area (CSA), soleus fiber properties and serum IGF-1 in rats. Rats were hindlimb suspended for 14 days or kept as controls (C, n = 7). Soleus muscles were isolated after HS (HS, n = 7) or after reambulation for either three (R3, n = 5) or seven days (R7, n = 6). Frozen serial sections of m. soleus were stained by primary monoclonal antibodies against MHCI. For measurement of concentration IGF-1 in the blood serum, test-system for IFA DSL-10-2800 Non-Extraction IGF-1 ELISA was used. Muscle mass was significantly reduced in HS (-35 %) but subsequently increased with reloading in R3 (-10 % to C) and was recovered to control values in R7 (+5 % to C). Fiber CSA was significantly reduced (-43 %) in HS and was greater in R7 than in HS and slightly greater than in R3. 14 days of HS resulted in a mean maximal tension reduced by 35 %. After 7 days of subsequent reloading the mean maximal specific tension was still low (-33 % to C) and didn't differ from HS level. The level in blood IGF-1 has obviously decreased during 14-day unloading by 48 %, remained at the same level in R3, and increased 10 fold in R7.     

Increased expression of basic fibroblast growth factor in hyperoxic-injured mouse lung

Basic fibroblast growth factor (bFGF) is a mitogenic polypeptide for a wide variety of cell types and has been immunolocalized in the rodent and human lung. We investigated the mRNA and protein expression of bFGF in hyperoxic-injured adult mouse lungs using northern blot analysis and immunohistochemistry. Mece (6–8weeks) were continuously exposed to 80% osygen up to 4 days. Levels of bFGF mRNA were increased from room air control on days 3 and 4 of hyperoxia. mRNA levels of acidic fibroblast growth factor (aFGF), fibronectin, and transin/stromelysin were also examined in this injury model. Similar to bFGF, the fibronectin and transin/stromelysin mRNA levels were increased after 3 days of hyperoxia. In contrast, the aFGF mRNA levels were gradually reduced on each day of hyperoxia. A rabbit polyclonal anti-bFGF antibody was used to determine the distribution and levels of expression in the hyperoxic-injured lungs. The room air control and day 1 hyperoxic-exposed lungs exhibited staining for bFGF in the basement membranes of the blood vessels, airways, and alveoli. Patchy but intense alveolar staining was prominent on day 4 of hyperoxia. The bFGF immunoreactivity of blood vessels and airways unaffected by the hyperoxia exposure. These results suggest that bFGF may play a role in the alveolar response to hyperoxic-induced injury by virtye of the altered mRNA levels and protein distribution in this injury model.     

Morphological and functional changes in the retina after chronic oxygen-induced retinopathy

The mouse model of oxygen-induced retinopathy (OIR) has been widely used for studies of retinopathy of prematurity (ROP). This disorder, characterized by abnormal vascularization of the retina, tends to occur in low birth weight neonates after exposure to high supplemental oxygen. Currently, the incidence of ROP is increasing because of increased survival of these infants due to medical progress. However, little is known about changes in the chronic phase after ROP. Therefore, in this study, we examined morphological and functional changes in the retina using a chronic OIR model. Both the a- and b-waves in the OIR model recovered in a time-dependent manner at 4 weeks (w), 6 w, and 8 w, but the oscillatory potential (OP) amplitudes remained depressed following a return to normoxic conditions. Furthermore, decrease in the thicknesses of the inner plexiform layer (IPL) and inner nuclear layer (INL) at postnatal day (P) 17, 4 w, and 8 w and hyperpermeability of blood vessels were observed in conjunction with the decrease in the expression of claudin-5 and occludin at 8 w. The chronic OIR model revealed the following: (1) a decrease in OP amplitudes, (2) morphological abnormalities in the retinal cells (limited to the IPL and INL) and blood vessels, and (3) an increase in retinal vascular permeability via the impairment of the tight junction proteins. These findings suggest that the experimental animal model used in this study is suitable for elucidating the pathogenesis of ROP and may lead to the development of potential therapeutic agents for ROP treatment.     

N-acetylcysteine inhibits hypoxic pulmonary hypertension most effectively in the initial phase of chronic hypoxia

Exposure to chronic hypoxia results in hypoxic pulmonary hypertension (HPH). In rats HPH develops during the first two weeks of exposure to hypoxia, then it stabilizes and does not increase in severity. We hypothesize that free radical injury to pulmonary vascular wall is an important mechanism in the early days of the hypoxic exposure. Thus antioxidant treatment just before and at the beginning of hypoxia should be more effective in reducing HPH than antioxidant therapy of developed pulmonary hypertension. We studied adult male rats exposed for 4 weeks to isobaric hypoxia (F(iO2) = 0.1) and treated with the antioxidant, N-acetylcysteine (NAC, 20 g/l in drinking water). NAC was given "early" (7 days before and the first 7 days of hypoxia) or "late" (last two weeks of hypoxic exposure). These experimental groups were compared with normoxic controls and untreated hypoxic rats (3-4 weeks hypoxia). All animals kept in hypoxia had significantly higher mean pulmonary arterial blood pressure (PAP) than normoxic animals. PAP was significantly lower in hypoxic animals with early (27.1 +/- 0.9 mmHg) than late NAC treatment (30.5 +/- 1.0 mmHg, P < 0.05; hypoxic without NAC 32.6 +/- 1.2 mmHg, normoxic controls 14.9 +/- 0.7 mmHg). Early but not late NAC treatment inhibited hypoxia-induced increase in right ventricle weight and muscularization of distal pulmonary arteries assessed by quantitative histology. We conclude that release of free oxygen radicals in early phases of exposure to hypoxia induces injury to pulmonary vessels that contributes to their structural remodeling and development of HPH.     

Effects of hyperoxia on postnatal intestinal development

Fetuses develop in a marked hypoxic environment in utero. Premature infants often require high concentrations of oxygen to survive and develop in an environment that would be considered an oxygen stress for the fetus. Postnatal hyperoxia alters organ development, but there is minimal research regarding the role of hyperoxia in intestinal development. We attempted to determine whether postnatal hyperoxia exposure alters intestinal growth and function by using a reliable, objective and sensitive set of methods to study region-specific postnatal intestinal maturation. Rat pups born naturally were placed in continual exposure to room air (normoxia) or 85% oxygen (hyperoxia) immediately after birth. Pups were sacrificed at 1 and 2 weeks of age. Intestines were removed and fixed in formalin. Average mucosal, submucosal, and muscularis thicknesses were measured on hematoxylin and eosin stained sections. Immunohistochemistry was performed using antibodies against NOS II. The staining intensity was determined and quantified for site-specific regions of intestinal sections. No differences in mucosal thickness, submucosal thickness, or muscularis thickness were measured in the duodenum, jejunum or colon at any age. At two weeks of age, the thickness of the ileal mucosa was significantly greater in the group reared in 85% oxygen, and the group exposed to room air demonstrated significantly greater NOS II protein concentration than the hyperoxia group within the distal villus, proximal villus/crypts, submucosa, and muscularis in the distal small intestine.     

Overexpression of Extracellular Superoxide Dismutase Protects against Brain Injury Induced by Chronic Hypoxia

Extracellular superoxide dismutase (EC-SOD) is an isoform of SOD normally found both intra- and extra-cellularly and accounting for most SOD activity in blood vessels. Here we explored the role of EC-SOD in protecting against brain damage induced by chronic hypoxia. EC-SOD Transgenic mice, were exposed to hypoxia (FiO2.1%) for 10 days (H-KI) and compared to transgenic animals housed in room air (RA-KI), wild type animals exposed to hypoxia (H-WT or wild type mice housed in room air (RA-WT). Overall brain metabolism evaluated by positron emission tomography (PET) showed that H-WT mice had significantly higher uptake of ¹⁸FDG in the brain particularly the hippocampus, hypothalamus, and cerebellum. H-KI mice had comparable uptake to the RA-KI and RA-WT groups. To investigate the functional state of the hippocampus, electrophysiological techniques in ex vivo hippocampal slices were performed and showed that H-KI had normal synaptic plasticity, whereas H-WT were severely affected. Markers of oxidative stress, GFAP, IBA1, MIF, and pAMPK showed similar values in the H-KI and RA-WT groups, but were significantly increased in the H-WT group. Caspase-3 assay and histopathological studies showed significant apoptosis/cell damage in the H-WT group, but no significant difference in the H-KI group compared to the RA groups. The data suggest that EC-SOD has potential prophylactic and therapeutic roles in diseases with compromised brain oxygenation.     

Decreasing intraocular pressure significantly improves retinal vessel density,cytoarchitecture and visual function in rodent oxygen induced retinopathy

We attempted to explore a noninvasive, easily applicable and economically affordable therapy for retinopathy of prematurity(ROP). Rat pups were raised in 80% oxygen from postnatal day 7 to P12, and returned to room air. Travoprost eye drops were administered twice a day for 7 days, to reduce intraocular pressure(IOP) by about 20%. Immunohistochemical staining was performed to visualize vessel endothelial cells, to analyze retinal neurons and cytoarchitecture. Behavioral experiments were carried out to test visual acuity and contrast sensitivity. At the end of the 7-day treatment, the number of vessels extending to the vitreous body was significantly reduced and retinal vessel density increased. This improvement was maintained to the end of the12 th week. In the central retina of the model group, the horizontal cells were completely wiped out, the outer plexiform layer was undetectable, and the rod bipolar cell dendrites sprouted into the outer nuclear layer. The treatment partially reverted these architectural changes. Most importantly, behavioral experiments revealed significantly improved visual acuity and contrast sensitivity in the treated group. Therefore, reducing IOP could potentially serve as a safe and economical measure to treat ROP.     

N-acetylcysteine increases the frequency of bone marrow pro-B/pre-B cells, but does not reverse cigarette smoking-induced loss of this subset

Background

We previously showed that mice exposed to cigarette smoke for three weeks exhibit loss of bone marrow B cells at the Pro-B-to-pre-B cell transition, but the reason for this is unclear. The antioxidant N-acetylcysteine (NAC), a glutathione precursor, has been used as a chemopreventive agent to reduce adverse effects of cigarette smoke exposure on lung function. Here we determined whether smoke exposure impairs B cell development by inducing cell cycle arrest or apoptosis, and whether NAC treatment prevents smoking-induced loss of developing B cells.

Methodology/Principal Findings

Groups of normal mice were either exposed to filtered room air or cigarette smoke with or without concomitant NAC treatment for 5 days/week for three weeks. Bone marrow B cell developmental subsets were enumerated, and sorted pro-B (B220⁺CD43⁺) and pre-B (B220⁺CD43⁻) cell fractions were analyzed for cell cycle status and the percentage of apoptotic cells. We find that, compared to sham controls, smoke-exposed mice have ∼60% fewer pro-B/pre-B cells, regardless of NAC treatment. Interestingly, NAC-treated mice show a 21–38% increase in total bone marrow cellularity and lymphocyte frequency and about a 2-fold increase in the pro-B/pre-B cell subset, compared to sham-treated controls. No significant smoking- or NAC-dependent differences were detected in frequency of apoptotic cells or the percentage cells in the G1, S, or G2 phases of the cycle.

Conclusions/Significance

The failure of NAC treatment to prevent smoking-induced loss of bone marrow pre-B cells suggests that oxidative stress is not directly responsible for this loss. The unexpected expansion of the pro-B/pre-B cell subset in response to NAC treatment suggests oxidative stress normally contributes to cell loss at this developmental stage, and also reveals a potential side effect of therapeutic administration of NAC to prevent smoking-induced loss of lung function.     

Preparing Serial Sections of Mature Corn and Wheat Kernels

Methods are described for preparing serial sections of paraffin-embedded mature corn and wheat kernels. Prior to embedding corn kernels are killed and fixed in formalin-aceto-alcohol (FAA), then steeped 5 days in 50% glycerol. After embedding by a special procedure, a thin slice is cut from one side of the kernel and the first few cell layers removed. The exposed surface is submerged in 20% glacial acetic acid in 60% ethanol for 2 or 8 days depending on the surface exposed, 2 days in air at 100% relative humidity at room temperature, and 2 days in air at 100% relative humidity at 8°C, successively. Wheat kernels, fixed in formalin-aceto-alcohol and embedded by the regular paraffin procedure, are similarly trimmed to expose a surface which is submerged in 20% glacial acetic acid in 60% ethanol for 2 days, 2 days in air at 100% relative humidity at room temperature and 2 days in air at 100% relative humidity at 8°C, successively. The corn and wheat kernels prepared by these methods give good serial sections when cut as thin as 14μ. The application of these methods to other seeds and caryopses is suggested.     

Carotid chemoreceptors, systemic blood pressure, and chronic episodic hypoxia mimicking sleep apnea.

We have described a rat model that responds to repetitive episodic hypoxia (12-s infusions of nitrogen into daytime sleeping chambers every 30 s, 7 h/day for 35 days) with an increase in diurnal systemic blood pressure. We hypothesized that afferent information from the peripheral chemoreceptors may be necessary to produce diurnal blood pressure elevation in this hypoxia model. Carotid body denervation (CBD) was accomplished by severing both carotid sinus nerves in two groups of male Wistar rats (250-375 g). Group 4 CBD rats were subjected to intermittent hypoxia for 35 days (3-5% nadir ambient O2) as described above, whereas group 5 CBD rats remained unhandled in their usual cages. Additional sham-operated controls included group 2 sham-"hypoxia" rats, which were housed in chambers identical to the hypoxia rats but supplied with compressed air instead of nitrogen, group 1 (not denervated) rats, which remained unhandled in their usual cages, and group 3 sham-operated rats, which were subjected to 35 days of intermittent hypoxia identical to group 4 CBD rats. Femoral arterial baseline and end-of-study blood pressures were measured in conscious rats. The group 3 rats exposed to episodic hypoxia displayed a 13-mmHg increase in mean blood pressure, whereas the other groups showed no significant change from baseline. Left ventricular hypertrophy was evident in all rats exposed to episodic hypoxia, but right ventricular hypertrophy was evident only in the group 4 rats. All CBD rats developed increased hematocrit and hemoglobin, while the group 3 rats (non-CBD, episodic hypoxia) did not. The baroreceptor reflex at baseline was not depressed in the CBD rats.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pulmonary protective effects of hyberbaric oxygen and N-acetylcysteine treatment in necrotizing pancreatitis

The purpose of this study is to analyze the protective effect of combining N-acetylcysteine (NAC) and hyberbaric oxygen (HBO) treatment in the lung tissue during acute pancreatitis. Sixty Sprague-Dawley male rats were randomly divided into five groups; Group I; Control group (n=12), Group II; pancreatitis group (n=12), Group III; pancreatitis + NAC treatment group (n=12), Group IV; pancreatitis + HBO treatment group (n=12), Group V; pancreatitis + HBO + NAC treatment group (n=12). HBO was applied postoperatively for 5 days, twice a day at 2.5 fold absolute atmospheric pressure for 90 min. Lung tissue was obtained for measuring malondialdehyde (MDA), superoxide dismutase (Cu/Zn-SOD) and glutathione peroxidase (GSH-Px) levels along with histopathological tissue examinations. This study showed that all three treated groups (HBO alone, NAC alone and combined HBO+NAC treatment) had pulmonary protective effects during acute necrotizing pancreatitis.     

Hyperbaric oxygen treatment attenuates cytokine induction after massive hemorrhage

We investigated the effect of hyperbaric oxygen treatment (HBO) on cytokine induction after hemorrhage, because hypoxia induces cytokines in vitro. Chronically cannulated conscious rats were subjected to 40 ml/kg of hemorrhage and resuscitated with the shed blood and twice the volume of saline either under room air (room air group) or under 100% oxygen at 3 atmospheres absolute (hyperbaric group). Rats exposed to HBO with no hemorrhage served as controls. Time course changes in plasma endotoxin level, arterial ketone body ratio (AKBR), serum tumor necrosis factor (TNF), interleukin-6 (IL-6), and their hepatic mRNA were detected in the three groups. Plasma endotoxin levels increased significantly after hemorrhage, and there were no significant differences between the room air group and the hyperbaric group. In the room air group, AKBR dropped rapidly after hemorrhage and became minimal at hour 1, which was associated with significant increases in TNF-alpha and IL-6 at both mRNA and circulating levels. HBO significantly attenuated decreases in AKBR after hemorrhage with a significant reduction of mortality and cytokine induction. These results indicate that HBO attenuated the cytokine induction after hemorrhage by improving liver ischemia, and they suggest that tissue hypoxia may be responsible, at least in part, for cytokine induction after massive hemorrhage.     

Acute severe carbon monoxide exposure in the rat: effects of hyperglycemia and hypoglycemia on mortality, recovery, and neurologic deficit.

Human and animal studies suggest a poorer outcome in the presence of abnormal blood glucose concentration during cerebral hypoxia-ischemia. It is unknown whether this is also the case in acute severe carbon monoxide poisoning. Using Levine-prepared rats, three groups were established and exposed to CO to answer this question: (1) hyperglycemics resulting from the administration of a 50% glucose solution, (2) hypoglycemics resulting from the administration of normal saline, and (3) untreated controls. The rats inhaled 2400 ppm CO for 90 min in the absence of anesthesia. Blood glucose was raised to a mean value of 402 mg/dL just prior to CO exposure in group 1. This resulted in an increased mortality rate (i.e., 54%), and during 4 h of room air recovery an impaired ability to regain body temperature, an increased plasma lactate dehydrogenase activity, and an increased neurologic deficit as compared with group 3. Hypoglycemia, which developed during CO exposure in group 2 (mean minimum glucose after 90 min, 44 mg/dL), resulted in an increased mortality rate (i.e., 46%), and during 4 h of room air recovery an impaired ability to regain body temperature and an increased neurologic deficit as compared with group 3. Blood glucose concentration in the rats in groups 2 and 3 that died during or shortly after CO exposure was significantly depressed relative to the survivors of those groups. Plasma insulin activity was elevated during CO exposure in group 1 as compared with group 3, but fell during recovery; insulin remained low throughout CO exposure and recovery in group 2. The results demonstrate the deleterious effects of both a very high and a very low blood glucose concentration during acute CO exposure.     

Effects of Prenatal and Postnatal Exposure to GSM-Like Radiofrequency on Blood Chemistry and Oxidative Stress in Infant Rabbits, an Experimental Study

We aimed to investigate the potential hazardous effects of prenatal and/or postnatal exposure to 1800 MHz GSM-like radiofrequency radiation (RFR) on the blood chemistry and lipid peroxidation levels of infant rabbits. A total of 72 New Zealand female and male white rabbits aged 1-month were used. Thirty-six female and 36 male were divided into four groups which were composed of nine infants: (i) Group 1 were the sham exposure (control), (ii) Group 2 were exposed to RFR, 15 min daily for 7 days in the prenatal period (between 15th and 22nd days of the gestational period) (prenatal exposure group). (iii) Group 3 were exposed to RFR 15 min/day (14 days for male, whereas 7 days for female) after they reached 1-month of age (postnatal exposure group). (iv) Group 4 were exposed to RFR for 15 min daily during 7 days in the prenatal period (between 15th and 22nd days of the gestational period) and 15 min/day (14 days for male, whereas 7 days for female) after they reached 1-month of age (prenatal and postnatal exposure group). Results showed that serum lipid peroxidation level in both female and male rabbits changed due to the RFR exposure. However, different parameters of the blood biochemistry were affected by exposure in male and female infants. Consequently, the whole-body 1800 MHz GSM-like RFR exposure may lead to oxidative stress and changes on some blood chemistry parameters. Studies on RFR exposure during prenatal and postnatal periods will help to establish international standards for the protection of pregnants and newborns from environmental RFR.     

Ultrastructural Evidence that Chick Primordial Germ Cells Leave the Blood-Vascular System Prior to Migrating to the Gonadal Anlagen

It is known that chick primordial germ cells (PGCs), after separation from the endoderm in early embryonic development, temporarily circulate via the blood-vascular system and eventually migrate to the gonadal anlagen. However, direct evidence that circulating PGCs leave the blood vessels is lacking. The purpose of present study is to describe the ultrastructural features of PGCs as they emerge from the blood vessels. PGCs leaving the blood vessels were first examined with semi-thin sections stained with toluidine blue. Then, some of the sections were re-embedded in Epon 812, and sectioned for electron microscopy. PGCs were observed emerging from the capillaries in the region posterior to the omphalomesenteric arteries of the embryo, between the splanchnic mesoderm and open-gut endoderm, at stages 15–18 (about 2.5 days of incubation). Ultrastructurally, PGCs exhibited the protruding, bulge-like cytoplasmic processes through the endothelial gaps in the capillary walls. Prior to emerging, intravascular PGCs seemed to stick to the endothelium of the blood vessels. Thus, our results offer ultrastructural evidence that the circulating PGCs exit the blood vessels prior to migrating to the gonadal anlagen.     

Exposure of pregnant dairy heifer to magnetic fields at 60 Hz and 30 microT

Thirty-two pregnant Holstein heifers weighing 499 +/- 45 kg, at 3.1 +/- .7 months of gestation and 21 +/- 2.0 months of age were confined and exposed to 30 microT magnetic fields (MFs) and a 12 h light/12 h dark light cycle. The heifers were divided into two replicates of 16 animals. Each replicate was divided into two groups of eight animals each, one group the non-exposed and the second, the exposed group. The animals were subjected to the different treatments for 4 weeks. After 4 weeks, the animals switched treatment, the exposed group becoming the non-exposed group and vice versa. Then the treatment continued for 4 more weeks. Catheters were inserted into the jugular vein, and blood samples were collected twice a week to estimate the concentration of progesterone (P4), melatonin (MLT), prolactin (PRL), and insulin-like growth factor 1 (IGF-1). Feed consumption was measured daily. The results indicated that exposure of pregnant heifers to MF similar to those encountered underneath a 735 kV high tension electrical power line for 20 h/day during a period of 4 weeks produces slight effects. This is evidenced by statistically significant higher body weight (1.2%), higher weekly body weight gain (30%), and decreases in the concentration of PRL (15%) and IGF-1 (4%) in blood serum. The absence of abnormal clinical signs and the absolute magnitude of the significant changes detected during MF exposure, make it plausible to preclude any major animal health hazard.     

Survivin expression in tuberous sclerosis complex cells

Tuberous Sclerosis Complex (TSC) is a tumor suppressor gene disorder with mutations of TSC1/TSC2 genes. This leads to the development of hamartomas that most frequently affect central nervous system, kidney, and skin. Angiomyolipomas are abdominal masses made up of muscle vessels and adipose tissues that grow mostly in proximity to kidneys and liver. Bleeding and kidney failure are the major justification for surgery. This study shows that angiomyolipoma-derived human smooth muscle TSC2-/- cells express the apoptosis inhibitor protein survivin when exposed to IGF-1. Survivin expression is also triggered whenever culture conditions perturb normal TSC2-/- cell function, such as the omission of EGF from the growth medium, the supplementation of anti-EGFR, blockade of PI3K and ERK, or inhibition of mTOR. Interestingly, single or simultaneous inhibition of PI3K by LY294002 and ERK by PD98059 does not prevent IGF-1-mediated survivin expression. Apoptogenic Smac/DIABLO, which is constitutively expressed by TSC2-/- A+ cells, is down-regulated by IGF-1 even in the presence of LY294002 and PD98059. These cells release IGF-1 by means of a negative feedback-regulated mechanism that is overrun when they are exposed to antibodies to IGF-1R, which increases the released amount by more than 400%. The autocrine release of IGF-1 may therefore be a powerful mechanism of survival of the tightly packed cells in the thick-walled vessels of TSC angiomyolipoma and in lymphangioleiomyomatosis (LAM) nodules. Future experimental therapies for TSC and LAM may result from the targeted inhibition of survivin, which may enhance sensitivity to TSC2 therapy.     

Tracheal vascular and smooth muscle responses to air temperature and humidity in dogs

Twenty-five dogs were anesthetized, paralyzed, and artificially ventilated. Their cranial tracheal arteries were perfused bilaterally with blood at constant flow, and the perfusion pressures (Patr) were measured. Tracheal smooth muscle function was assessed by recording changes in external diameter (delta Dtr). The perfused segment of the trachea was exposed to air at a constant unidirectional airflow of 25 l/min. Group 1 (n = 6) was exposed to cold dry air, ambient room air, and hot dry and hot humid air, each for 10 min with exposures starting from zero flow. The tracheal vascular responses to all four conditions were small vasodilations (delta Patr from -2 to -6%) followed by recovery or small vasoconstrictions. In group 2 (n = 19), exposures to cold dry and hot humid air were preceded and followed by body-temperature fully humidified air. Cold dry air caused a sustained vasodilation (delta Patr -9.0 +/- 1.1%), and hot humid air usually caused a biphasic response: a vasoconstriction (delta Patr 4.4 +/- 1.0%) followed by a vasodilation (delta Patr -5.7 +/- 1.9%). The warm humid air after cold dry air or hot humid air caused a further vasodilation, which lasted a short time after cold dry air (delta Patr -3.7 +/- 0.4%) but greater than 10 min after hot humid air (delta Patr -13.8 +/- 1.4%). In both groups, all exposures that cooled the trachea (cold dry air, ambient room air, and hot dry air) caused smooth muscle contraction, and hot humid air that warmed the trachea caused relaxation.