Ad-lib Water Research Articles

Impact of Rehydration Following Systemic Dehydration on Vocal Fold Gene Expression.

Biological data on the beneficial effects of vocal fold rehydration are lacking. This study aimed to examine the effects of acute systemic dehydration on vocal fold gene expression and determine whether rehydration would reverse these changes. Male New Zealand White rabbits (N = 24, n = 8/group) provided the animal model. Systemic dehydration was induced by 5 days of water volume restriction. Rehydration was provided by ad-lib water for 3 days following dehydration. Euhydrated rabbits were used as the control group. Vocal fold tissue was dissected. Seventeen genes were selected based on physiological function and role in supporting vocal fold structure, oxidative stress, hemodynamics, and extracellular matrix turnover. Relative gene expression was assessed by RT-qPCR. Rehydration following systemic dehydration can modulate gene expression, with expression patterns suggesting that rehydration reverses dehydration-induced changes in over half of the tested genes. CLIC5 (chloride intracellular channel 5) and EFEMP1 (EGF containing fibulin extracellular matrix protein 1) genes were significantly upregulated in the dehydration group compared with the euhydrated control. A1BG (alpha-1B-glycoprotein) and IL1RAP (interleukin 1 receptor accessory protein) were downregulated by rehydration compared with the dehydration group. This study provides molecular evidence for a transcriptional response to rehydration following acute systemic dehydration in the vocal folds. These data are the first to study gene expression following realistic dehydration and rehydration paradigms and provide biological data to support clinical recommendations to increase water intake after acute dehydration. NA Laryngoscope, 133:3499-3505, 2023.

Forced swimming stress increases natatory activity of lead-exposed mice.

Recent evidence points to the relationship between lead toxicity and the function of the hypothalamic-pituitary-adrenal axis, which suggests that lead exposure could influence how an individual cope with stress. Here we test this hypothesis by investigating the behavioral effects of lead exposure in mice during the forced swimming test (FST), a parading in which animals are exposed to a stressful situation and environment. Swiss mice received either 180ppm or 540ppm of lead acetate (Pb) in their ad-lib water supply for 60-90days, starting at postnatal day 30. Control (Ctrl) mice drank tap water. At the end of the exposure period, mice were submitted to a 5-min session of FST or to an open-field session of the same duration. Data from naïve animals showed that corticosterone levels were higher for animals tested in the FST compared to animals tested in the open-field. Blood-lead levels (BLL) in Pb-exposed mice ranged from 14.3 to 106.9µg/dL. No differences were observed in spontaneous locomotion between Ctrl and Pb-exposed groups in the open-field. However, in the FST, Pb-treated mice displayed higher swimming activity than Ctrl ones and this effect was observed even for animals with BLL higher than 20µg/dL. Furthermore, significant differences in brain glutathione levels, used as an indicator of led toxicity, were only observed for BLL higher than 40µg/dL. Overall, these findings suggest that swimming activity in the FST is a good indicator of lead toxicity and confirm our prediction that lead toxicity influences behavioral responses associated to stress.

Potential for Use of Erythritol as a Socially Transferrable Ingested Insecticide for Ants (Hymenoptera: Formicidae).

Ants are significant structural and agricultural pests, generating a need for human-safe and effective insecticides for ant control. Erythritol, a sugar alcohol used in many commercial food products, reduces survival in diverse insect taxa including fruit flies, termites, and mosquitos. Erythritol also decreases longevity in red imported fire ants; however, its effects on other ant species and its ability to be transferred to naïve colony members at toxic doses have not been explored. Here, we show that erythritol decreases survival in Tetramorium immigrans Santschi (Hymenoptera: Formicidae) in a concentration-dependent manner. Access to ad-libitum water reduced the toxic effects of erythritol, but worker mortality was still increased over controls with ad-lib water. Foraging T. immigrans workers transferred erythritol at lethal levels to nest mates that had not directly ingested erythritol. Similar patterns of mortality following erythritol ingestion were observed in Formica glacialis Wheeler (Hymenoptera: Formicidae), Camponotus subarbatus Emery (Hymenoptera: Formicidae), and Camponotus chromaiodes Bolton (Hymenoptera: Formicidae). These findings suggest that erythritol may be a highly effective insecticide for several genera of ants. Erythritol's potential effectiveness in social insect control is augmented by its spread at lethal levels through ant colonies via social transfer (trophallaxis) between workers.

Evaluation of Intraperitoneal and Incisional Bupivacaine or Levobupivacaine for Postoperative Analgesia in Ovariohysterectomized Dogs

Background: Ovariohysterectomy (OHE) is the most commonly performed elective surgical procedure in companion animals. OHE offers benefits of control of population and decreased risk of potentially life-threatening diseases such as mammarian tumours and pyometra. Traditional OHE intervention causes inflammation and pain due to trauma during organ manipulation. The purpose of this study was to compare the effect of intraperitoneal and incisional administration of bupivacaine (BP) or levobupivacaine (LP) on postoperative analgesia in dogs undergoing the OHE procedure.Materials, Methods & Results: A total of 24 mix-breed bitches aged between 1 - 3 years and weighed 19 - 20 kg were used in this study. The animals were divided into three groups as control (n = 8), BP (n = 8) and LP group (n = 8). The animals were kept under surveillance at the hospitalisation unit of the animal hospital for one day before the elective OHE. The dogs were fasted for 12 h before the surgery, with adlib water consumption. Atropine sulphate 0.045 mg/kg was administered subcutaneously approximately 30 min before general anaesthesia. Midazolam (0.3 mg/kg) was intravenously injected into all dogs for pre-anaesthetic medication. After sedation, anaesthesia was induced with propofol (4 mg/kg, IV) and then the dogs were orotracheally intubated using cuffed endotracheal tubes. General anaesthesia was maintained by administration of 2% isoflurane. The ventral abdomen was prepared aseptically for OHE following the general anaesthesia. All animals were operated on by the same surgeon. During surgery, sprayed bupivacaine 0.5% (4.4 mg/kg) with an equal volume of saline in BP group, levobupivacaine 0.5% (4.4 mg/kg) with an equal volume of saline in LP were then applied over the ovaries, uterine broad ligaments and cervix uteri. After removal of the uterine body, either LP or BP was sprayed to left and right, or cranial and caudal parts of the abdominal cavity. Finally, the incision line was sprayed before closing the skin. The control group received only sprayed saline. The pain evaluation was carried out with modified Melbourne pain scoring scale. To determine cortisol concentrations, blood samples were taken before anaesthesia induction (baseline) and postoperative 0, 0.5, 1, 2, 4, 6, 12 and 24 h. Postoperative pain scores were higher in the control group than BP and LP groups following surgery at 30 min, 1st, 4th, and 6th h. In all groups, cortisol levels increased postoperatively, whereas they decreased more rapidly in BP and LP groups. There was a steady increase at postoperative 0 min, 30 min, 1st, 2nd, 4th and 6th h in the control group and at postoperative 0 min, 30 min and 1 h in BP and LP groups (P < 0.05).Discussion: Intraperitoneal and incisional bupivacaine shows significantly superior postoperative pain management benefits after the closure of skin, compared to untreated dogs and it is also superior to lidocaine treatment at 0.5 h following the visual analogy pain assessment system. In the present study, the observation of lower pain scores in BP group at 0.5, 1, 4 and 6 h as compared to the control group was similar to findings of other studies. LP group also showed decreased pain scores at above-mentioned h without any significant difference. However, only in LP group, pain scores at 24 h were lower than postoperative pain scores. In conclusion, it is suggested that sprayed intraperitoneal and incisional BP and LP are very effective for preventing postoperative pain ovariohysterectomized dogs.

Toxicology studies of a chemical mixture of 25 groundwater contaminants: hepatic and renal assessment, response to carbon tetrachloride challenge, and influence of treatment-induced water restriction.

Because groundwater contamination is an important environmental concern, we examined the hepatic and renal effects of repeated exposure to a mixture of 25 chemicals frequently found in groundwater near hazardous-waste disposal sites and the effect of such exposure on carbon tetrachloride (CCI4) toxicity. Adult male F-344 rats received ad libitum deionized water and feed (Ad Lib Water) or ad libitum 10% MIX (referring to 10% of a technically achievable stock mixture) and feed for 14 d. Because exposure to the 25-chemical mixture via the drinking water resulted in decreased water and feed consumption, restricted deionized water and feed controls (Restricted Water) were included. On d 14, rats were gavaged with 0, 0.0375, 0.05, 0.075 or 0.15 ml CCl4/kg, and hepatic and renal toxicity assessed 24 h later. Little or no hepatic and renal toxicity was observed in rats exposed to 10% MIX alone. No hepatic or renal lesions occurred that could be attributed to 10% MIX alone. Slight but statistically significant alterations, of uncertain biological significance, resulted from the water treatments: 10% MIX increased alanine aminotransferase, urea nitrogen (BUN), and BUN/creatinine ratio; Restricted Water increased 5'-nucleotidase and decreased alkaline phosphatase. Relative kidney weight was increased by both 10% MIX and Restricted Water. CCI4 resulted in significant dosage-dependent hepatotoxicity in all three water treatment groups but had little or no effect on renal indicators of toxicity. Relative to Ad Lib Water, significantly greater hepatotoxicity occurred in both 10% MIX and Restricted Water rats. The response to CCI4 in the Restricted Water rats was similar to that of 10% MIX rats, indicating that a substantial portion of the effect of 10% MIX on CCI4 hepatotoxicity is due to decreased water and feed intake.

Light/Dark cycle modulates food to water intake ratios in rats

Ad lib water intake of rats displays two prominent features: Water intake is temporally and quantitatively associated with food intake, and water intake is noctunal. Physiological mechanisms linking water and food intake suggest that the rhythmicity in water intake may be at least partially driven by a rhythmicity in food intake. The present study examined whether the daily rhythm of rats modulates the association of food and water intake. Rats were housed under light/dark cycles and continuously monitored for temporal and quantitative patterns of ad lib food and water intake. The results indicate that the water/food ratio is much lower for meals consumed in the light phase than in the dark phase. The above results suggest a rhythmic modulation of the mechanisms linking food and water intake. We suggest that much of the complex rhythm of drinking stems from several interacting factors. 1) Food intake is nocturnal. 2) Food intake induces water intake by physiological mechanisms. 3) The amount of water intake induced by food intake is influenced by rhythmic factors.

Lesions of the MPO or AV3V: Influences on fluid intake

Electrolytic lesions in the MPO of rats had no significant effects on ad lib food and water intake, but impaired the drinking response to 1 M NaCl. Large MPO lesions also produced a persistent increase in plasma osmolality. In Experiment 2, we depleted neurons from the MPO of rats by iontophoretic application of the neurotoxin kainic acid (KA) which destroys nerve cell bodies without damage to fibers of passage. KA-induced neuron depletion in the MPO of rats significantly reduced the drinking response to 1.0 M saline, to 30% PG, and to 30 μg/kg isoproterenol. Ad lib water intake and drinking responses to food or water deprivation, to low concentrations (0.5 M) of hypertonic saline, to low concentrations (10% or 20%) of PG, and to systemic administration of 1.5 mg/kg angiotensin II were within the normal range. In Experiment 3, rats with electrolytic lesions that were strictly confined to the tissue immediately surrounding the wall of the anteroventral portion of the third ventricle (AV3V), without invading the MPO displayed normal ad lib food and water intake and plasma osmolality as well as drinking responses to water deprivation, hypertonic saline (0.5 or 1.0 M), angiotensin II (1.5 mg/kg) and isoproterenol (30 μg/kg).

Area postrema lesions increase drinking to angiotensin and extracellular dehydration

The area postrema (AP) is a circumventricular organ of the caudal medulla oblongata. This structure lacks a blood brain barrier and contains high concentrations of angiotensin II (AII) receptors. Because AII is a participant in the arousal of thirst, we have examined the effect of AP lesions upon drinking in response to exogenous AII and in response to various thirst challenges. We have found that rats with AP lesions (APL) drink more water than control rats in response to isoproterenol and polyethylene glycol. Rats with AP lesions also drank two times as much water as controls in response to subcutaneous injection of exogenous AII. Ad lib water intakes of APL and control rats were not different. Furthermore, drinking in response to 21 hr water deprivation or cell dehydration did not differ for APL and control rats. Our results suggest that AP lesions selectively enhance extracellular thirst, especially the component of that thirst mediated by AII.

Variations in the strength of conditioned taste aversion in rats as a function of time of inducement

In an experiment to determine the optimal time of day for the establishment of taste-aversion learning, 24 male albino rats were divided into four equal groups. Following 14 days of ad-lib water and food, Group 1 animals were water deprived beginning at 4 a.m. on Day 15. Group 2 was also introduced to water deprivation on Day 15 beginning at 10 a.m.; likewise, Group 3 began at 4 p.m. and Group 4 started at 10 p.m. After 24 h of deprivation, the taste cues (1.5 grains of saccharin in 600 cc of tap water) were made available to each group at 4 a.m., 10 a.m., 4 p.m., or 10 p.m., respectively. After allowing the animals to drink the taste cue for 1 h, the drinking tubes were removed, and, subsequent to a 30-min interval, each animal was injected with cyclophosphamide, an illness-inducing drug. The subjects were then given 4 days to recover from the ensuing illness with water available ad lib. Upon recovery, the animals in each group were again water deprived for 24 h using the same times as on Day 15. The next day, all groups were tested for aversions at 4 a.m., 10 a.m., 4 p.m., or 10 p.m., respectively, by giving each animal in each group access for 1 h to two bottles: one filled with tap water and the other filled with the taste cue. Results indicated that aversions were strongest for the 4 p.m. animals and weakest for the 10 p.m. group. The 4 a.m. and 10 a.m. animals fell between the other two groups in terms of aversion strength.