Biomedical subjects

F W Edens

Publications and source records attributed to F W Edens.

At least 55 records · Page 3Linked to original sources

PubMed1988

Pharmacological evaluation of central adrenergic involvement in chlordecone-induced hypothermia.

Adrenergic involvement in the hypothermia produced by systemically administered chlordecone (CLD) was evaluated in the rat using intracisternal pretreatment with 6-hydroxydopamine (6-OHDA), alpha-adrenergic receptor antagonists (phenoxybenzamine and phentolamine) and beta-adrenergic antagonists (propranolol and atenolol). The effect of intraperitoneal administration of 75 mg/kg of chlordecone on colonic temperature (Tcol) in male Fischer-344 rats was measured 7 days after administration of 6-OHDA and 30 min following pretreatment with the receptor antagonists. Prior depletion of catecholamines in brain with 250 micrograms of 6-OHDA administered intracerebrally attenuated hypothermia induced by chlordecone, without affecting basal Tcol. Phenoxybenzamine (10 or 20 micrograms) and phentolamine (5 or 10 micrograms) also reduced the hypothermic response to chlordecone. The beta-adrenergic receptor antagonists propranolol (50 or 100 micrograms) and atenolol (10 or 20 micrograms) did not attenuate chlordecone-induced hypothermia. These data suggest that the hypothermia induced by chlordecone is a result of alterations in central alpha-adrenergic functions, possibly involved with the sympathetic control of vasomotor tone.

Animals↗

PubMed1988

Subclinical ammonia toxicity in steers: effects on blood metabolite and regulatory hormone concentrations.

The effects of subclinical NH3 toxicity on circulating and regulatory hormone concentrations were investigated in seven Hereford steers. Ammonium chloride (NH4Cl) was infused via a right jugular vein catheter at a rate of 12 mumol NH4Cl.kg BW-1.min-1 for 240 min. This was preceded (PRE) and followed (POST) by saline infusions of 120 and 180 min, respectively. Blood samples were taken at 20-min intervals via a left jugular vein catheter. Metabolite and hormone concentrations during NH4Cl and POST periods were compared to PRE values using the Student's t-test procedure. Plasma NH3 was elevated rapidly (P less than .001) and peaked at 503 micrograms/dl 220 min into NH4Cl infusion. Plasma urea-N and glucose increased (P less than .001) 39 and 12%, respectively, during NH4Cl infusion and remained elevated 180 min POST. Whole blood L-lactate concentrations peaked (P less than .05) at 18% above PRE between 160 and 240 min into the NH4Cl infusion and gradually returned to PRE values, whereas pyruvate levels were not altered (P greater than .10). Plasma nonesterified fatty acids peaked (P less than .001) at 94% above PRE levels 40 min into NH4Cl infusion, thereafter declining to PRE concentrations. Whole blood acetoacetate and beta-hydroxybutyrate concentrations were not altered (P greater than .10) by NH4Cl administration. Plasma insulin concentration decreased (P less than .05) 26 to 46% during NH4Cl infusion and increased (P less than .05) 89 to 122% during POST. Plasma glucagon levels were not altered by NH4Cl infusion, so molar insulin:glucagon ratio changes resembled those of insulin. Plasma epinephrine, norepinephrine and dopamine did not vary (P greater than .10) with treatment. These results support the hypothesis that the hyperglycemia observed during hyperammonemia may result from an under-utilization of glucose by insulin-sensitive tissues.

Ammonia↗

PubMed1987

Chlordecone-induced effects on thermoregulatory processes in the rat.

To investigate the mechanism(s) involved in chlordecone (CLD)-induced hypothermia, we examined colonic (Tcol) and tail skin (Tsk) temperatures, preferred ambient temperature (Ta), evaporative water loss, and metabolic rate following CLD exposure in the rat. Single ip dosages (0, 50, and 75 mg/kg) in corn oil were administered to Fischer-344 rats. At a Ta of 22.5 degrees C, Tcol was reduced by 50 and 75 mg/kg as early as 0.5 hr, and this effect persisted for 4 hr after dosing. Tcol was increased 24 hr after both CLD dosages. Tsk was elevated 2, 3, 4, and 6 hr after 75 mg/kg and 2 hr after 50 mg/kg. At Ta of 30.5 degrees C, Tcol was decreased at early exposure times after both dosages and was increased 3, 4, and 6 hr after 75 mg/kg. At 10.0 degrees C, an enhanced hypothermia was observed 1-6 hr following 50 and 75 mg/kg CLD. The preferred Ta was significantly decreased by approximately equal to 2.8 degrees C following CLD exposure while activity within the temperature gradient was unchanged. At 25.0 degrees C, evaporative water loss was decreased while metabolic rate was not affected by CLD administration. To study the enhanced hypothermia at 10.0 degrees C, metabolic rate was measured continuously for 2 hr following 75 mg/kg CLD and found to be significantly different from controls. The intensified hypothermia in the cold may be due to the inability of the CLD-treated rat to stimulate metabolic thermogenesis in response to cold in addition to the loss of body heat following cutaneous vasodilation. These data suggest that CLD-induced hypothermia at a neutral Ta is associated with cutaneous vasodilation and not with a decreased metabolic rate or increased evaporative water loss.

Animals↗

PubMed1987

Effect of cage density and rank in peck order on brain regional monoamines in adult male Coturnix coturnix japonica.

1. In adult male Coturnix coturnix japonica neither norepinephrine (NE) nor serotonin (5HT) in various brain regions were affected by caging density (174 cm2-8/cage; 348 cm2-4/cage; 696 cm2-2/cage). Dopamine (DA) in diencephalon was elevated in high density cages. 2. Peck order rank was assigned on the basis of feather distribution on head, neck and back and lesions on head and back. 3. Upper strata peck order rank was associated with significantly lower levels of brain regional NE and DA compared to lower strata peck order rank. 4. Peck order rank did not affect brain regional 5HT. 5. The results indicate significant individual behavioral-neuroendocrine interaction leading to reproductive dysfunction.

Animals↗

PubMed1987

Effect of caponization on central nervous system monoamines in the Japanese quail.

Depletion of brain regional norepinephrine (NE), dopamine (DA) after alpha methyl-paratyrosine (AMT), and serotonin (5HT) were measured in intact and caponized adult male Japanese quail (Coturnix coturnix japonica). Telencephalon, diencephalon, and cerebellum DA was depleted by AMT treatment, but brain stem was not affected. AMT-induced depletion of NE was greatest in telencephalon, diencephalon, and brain stem of capons. Neither caponization nor AMT affected brain regional 5HT. The results from this work indicate that caponization will affect catecholamine dynamics in brain regions other than the hypothalamus.

Animals↗

PubMed1987

Manifestations of social stress in grouped Japanese quail.

Physiological manifestations of social stress in stable and unstable (resident and visitor) pairs of adult male Japanese quail (Coturnix coturnix japonica) were compared after 7, 14, 21 and 28 days of regrouping. Unstable pairs had reduced body and relative testes (mg/100 g) weights. Plasma cholesterol was increased significantly in unstable pairs, and adrenal cholesterol was reduced significantly by daily regrouping of unstable pairs. Twelve consecutive days of ACTH treatment (2, 4 or 8 IU/100 g body wt given intramuscularly) to birds in stable pairs induced a decrease in body and relative testes weights. The results were similar to those found in birds subjected to daily regrouping.

Adrenal Glands↗

PubMed1987

Agonistic behavior and neurochemistry in grouped Japanese quail.

Aggressive behavior and whole brain neurochemistry were measured in stable and unstable pairs of male Coturnix coturnix japonica. Aggressive pecking peaked on day 5 of the daily regrouping regime and returned to a basal level on day 14. Aggressive behavior was associated with increased brain norepinephrine (NE), dopamine (DA), and acetylcholinesterase (AChE) in unstable pairs. Habituation (12-15 days) and DA response to daily regrouping and inanition were inversely related in unstable and stable pairs respectively. Normal whole brain NE increases were attenuated in unstable pairs.

Acetylcholinesterase↗

PubMed1987

The posthatch physiology of the turkey poult--I. Growth and development.

Daily body, heart, liver, spleen, pancreas and bursa of Fabricius weights of developing turkey poults were measured. Neither organ nor body weight was affected by sex of the poults during the first 10 days posthatch. Decreases in growth were apparent between days 3 and 6 or 7 and 9 posthatch and coincided with peaks in early mortality.

Aging↗

PubMed1987

The posthatch physiology of the turkey poult--II. Hematology.

Packed cell volume, total leukocytes, total erythrocytes, hemoglobin, mean cell volume and mean corpuscular hemoglobin concentration of the poult were analyzed daily for the first 10 days posthatch. Sexually dimorphic effects on hematological parameters were not apparent, but there was a sex X day interaction for all parameters except hemoglobin indicating that males were slower to develop/respond to critical stimuli. The study revealed a latency in production of erythrocytes and leukocytes in posthatch males and females which coincided temporally with early poult mortality.

Aging↗

PubMed1987

Effect of prefeeding on physiological parameters associated with turkey poult mortality.

A commercially available antibiotic and nutrient solution was prefed by gavage into the crops of newly hatched poults, which were then brooded under standard conditions of continuous lighting, 35-C temperatures, and ad libitum feed. Treated poults exhibited higher feed consumption, hematocrits, and total red blood cells during the week following the prefeeding regime. Prefeeding partially ameliorated the typically low hematological parameters that have been associated previously with early poult mortality. The results of this study suggest that prefeeding an antibiotic and nutrient solution significantly improves the welfare of poults during the 1st week after hatching.

Animals↗

PubMed1987

Direct administration of chlordecone into Japanese quail eggs has persistent effects on conditioned behavior of adults.

Chlordecone (0.1 to 10 mg) or corn oil vehicle was injected into Japanese quail eggs on day 1 of incubation. Higher doses (0.5-10 mg per egg) produced tremor and ataxia at hatching and dose-related decreases in hatchability and survivability. Doses lower than 0.25 mg per egg had no effects. Gonad weights were not affected at 12 weeks of age. A second study examined the effect of injecting 0.5 mg of chlordecone into the egg on day 1, 3, 7 or 14 of incubation. Chlordecone-induced tremor was present at hatching regardless of the day of injection. Significant decreases in hatchability and increases in embryonic mortality were seen when chlordecone was injected on day 1 of incubation. Survivability to 5 weeks of age was decreased in birds receiving chlordecone on day 1 or 3 of incubation. At 75 to 84 days of age, egg production was decreased only in birds injected on day 1 of incubation. The offspring from these studies were mated and the hatchability and reproductive capability of these birds was studied at 75 to 84 days of age and found to be not significantly affected. In a third study, birds exposed to 0.5 mg of chlordecone or vehicle on day 1 of incubation were trained as adults in a food reinforced operant task. Exposure to chlordecone affected performance during the first 3 of 15 days of a match-to-sample task. The baseline response rate of these animals on a food reinforced random interval 60 sec schedule was then determined. During the last two weeks of asymptotic performance, chlordecone-exposed birds had a significantly lower rate of responding than controls. These data indicate that in ovo exposure to chlordecone can have significant long-term effects on conditioned behavior and egg production, particularly if exposure occurs on day 1 of incubation.

Animals↗

PubMed1985

Hatch weight selection: effect on post-hatch growth in the Japanese quail (Coturnix coturnix japonica).

The post-hatch growth of Japanese quail, weight selected at hatch, was investigated. The quail were grouped according to hatch weight as follows: Group I, 5.5-6.2 g; Group II, 6.3-7.0 g; and Group III, 7.1-7.6 g. Group III quail were 25 and 12% heavier at hatching than Group I and II quails, respectively, and reached a mature body weight which was 38 and 12% heavier than Group I and II quails, respectively. Gompertz growth parameters were not different in any of the groups. Feed and water consumption (g/kg body weight) rates were not significantly different among the three groups.

Aging↗

PubMed1985

Assessment of the male reproductive system in the preweanling rat following Mn3O4 exposure.

Long-Evans rat pups were dosed orally from birth to 21 d with particulate Mn3O4 to obtain a daily dose of 0, 71, or 214 micrograms Mn/body weight . d. Assessments of the hypothalamic, pituitary, or testicular functions were determined by measuring the endogenous or stimulated serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and/or testosterone (T) at 21 or 28 d of age. Body, testes, and seminal vesicles weight and tissue concentrations of Mn were also evaluated. Only slight Mn treatment effects were seen in body and testes weights. No effects were seen either on unstimulated or stimulated FSH or LH serum concentrations. Although no Mn treatment effects were seen on endogenous or 2 h human chorionic gonadotropin (hCG) stimulate serum T concentrations, there was a reduction in the serum T following 7 d of hCG stimulation. The hypothalamic Mn concentrations in animals with these reproductive effects were three times those where alterations in the dopaminergic pathway have been reported. However, no indication of hypothalamic or pituitary malfunction was found. These results suggest that the site of Mn damage that causes depression of sustained serum T concentration is in the testicular Leydig cell.

Administration, Oral↗

PubMed1985

Effects of chronic high-level manganese exposure on male behavior in the Japanese quail (Coturnix coturnix japonica).

Male Japanese quail were chronically exposed to 5000 ppm manganese (Mn) as particulate manganese oxide (Mn3O4) in their diet from hatching to 75 days of age. No decrements in growth or in other indices of general toxicity were noted. There were significant (P less than .05) age-related increases in general locomotor activity in the control group, although no significant (.05 less than P less than .10) increases were seen in the Mn-treated group. Both control and Mn-treated groups had significant (P less than .05) age-related increases in aggressive behavior with an overall significant (P less than .05) treatment-related depression. Serum testosterone concentration was only slightly depressed (.05 less than P less than .01) in the 75 day-old, Mn-treated quail. Both the control and Mn-treated quail had higher liver Mn concentrations than previously reported in rodents. Both control and Mn-exposed quail accumulated 5 to 10 times more Mn in their livers than similarly treated rodents. This study indicated that the Japanese quail was less sensitive to particulate Mn3O4 exposure than rodents treated comparably.

Aggression↗

PubMed1985

Magnesium, calcium, and phosphorus content of shells from hatching and nonhatching turkey eggs.

Shells of hatching and nonhatching Large White turkey eggs were examined for magnesium, calcium, and phosphorus content. Eggshells containing embryos that hatched contained significantly (P less than .05) more magnesium than shells from nonhatching eggs. No differences were seen in their calcium content. Eggshells from pipped eggs contained significantly (P less than .05) more phosphorus than shells from eggs that were not pipped or those that hatched. Calcium and magnesium in turkey eggshells declined as time in lay increased. Injections of exogenous magnesium both at setting and transfer significantly (P less than .05) depressed hatchability, whereas exogenous calcium injected at transfer significantly (P less than .05) improved hatchability. Injections of exogenous calcium at the time of setting significantly (P less than .05) depressed hatchability. It was concluded that the mineral content of turkey eggshells may influence embryo physiology and hatchability.

Animals↗

PubMed1985

Whole brain acetylcholinesterase activity in lead-exposed Japanese quail.

A study was conducted in which male and female Japanese quail were fed dietary lead as lead acetate from hatch through 12 weeks of age. Lead was added to the diet at 0, 1, 10, 100, and 1000 mg/kg feed. Significant reductions in whole brain acetylcholinesterase (AChE) activity were found at all treatment levels. Additionally, a sexual dimorphism in brain weight and AChE activity was found. Breeding males had heavier brain weights and lower AChE activity than females. Brain weight was not affected by lead treatment. However, females exhibited a greater lead-induced decrease in AChE activity.

Acetylcholinesterase↗

PubMed1983

Influence of age on the temperature response of chickens to Escherichia coli and Salmonella typhimurium endotoxins.

An experiment was conducted to investigate the influence of age on the temperature responses of chickens given bacterial endotoxins. Broiler cockerels 1 to 8 weeks of age received a single intravenous injection of either distilled water (controls), Escherichia coli 0127:B8, or Salmonella typhimurium endotoxins. Rectal temperatures were recorded before and after injection, the birds were placed in an environmental chamber preheated to 33 C, and thereafter rectal temperatures were taken every 30 min for 180 min. In one-week-old chicks, a significant temperature loss was found 30 min after E. coli treatment, and this was followed 60 min later by a significant increase in rectal temperature. The E. coli and S. typhimurium treatments caused a .4 and .5 C increase, respectively, in 2-week-old chicks. Birds aged 3 to 8 weeks developed fevers with maximum changes in rectal temperatures ranging from .3 to 1.6 C. Seven- and eight-week-old chicks developed the highest and most persistent fevers. The febrile response of 5 to 8 week-old chicks was of longer duration than that of younger chicks. It was concluded that the febrile response following endotoxin administration is affected by age.

Age Factors↗

PubMed1983

Grouping in Japanese quail. 1. Agonistic behavior during feeding.

Agonistic behavior in male Japanese quail, shown by aggressive pecking after feed restriction, was potentiated in unstable groups (a visitor bird moved to a new cage containing an unfamiliar resident each 24-hr period) but not in stable (a pair that was never changed once the birds were placed in cages) groups. The resident quail were more aggressive than either visitors or individuals of the stable groups. Ambivalent behavior (behavior characterized by an aggressive action followed immediately by a submissive posture) during feeding competition was observed in both the unstable and stable groupings. The ambivalent behavior appeared to be a conditioned response and was probably a result of the motivation to feed after a period of feed deprivation. During the experimental period the stable pairs of quail gained 28% of their initial body weight, but the resident and visitor quail, which were in the unstable grouping, gained only 15 and 13%, respectively. The differences in percentage weight gain were significant. Paired testes weights of the resident and visitor quail were significantly less than those of the stable birds.

Aggression↗