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Biomedical subjects

C W Qualls

Publications and source records attributed to C W Qualls.

At least 37 records · Page 2Linked to original sources
PubMed1996

Environmental, age, and sex effects on cotton rat (Sigmodon hispidus) hematology.

We determined the effects of sex, age, and environment (inbred, captive-wild, and wild animals) on selected blood parameters of the cotton rat (Sigmodon hispidus) in central Oklahoma (USA) from 1990 to 1994. Male and female cotton rats had similar blood profiles. Age-related differences were confined to differential white blood cell counts where adults possessed greater numbers of neutrophils and lower numbers of lymphocytes compared to juveniles. Environment had a strong influence on many hematological parameters. Hematocrit, hemoglobin concentration, RBC count, and eosinophil number were generally greater for wild stocks compared to inbred animals, and differences were more pronounced for adults than juveniles.

Aging↗
PubMed1996

Effects of feeding Artemisia filifolia and Helenium flexuosum on rabbit cytochrome P450 isozymes.

Six groups of 4 rabbits each were treated as follows: Control; phenobarbital (PB); 3-methylcholanthrene (3MC); proadifen hydrochloride (SKF-525A); Artemisia filifolia and Helenium flexuosum. Prototype P450 inducers (PB and 3MC) increased basal hepatic cytochrome P450 content by 2-3 fold whereas the P450 inhibitor (SKF-525A) had no effect on basal cytochrome P450 content. PB-induction of hepatic microsomes significantly increased the rate of dealkylation of long alkyl chain alkoxyresorufin ethers, benzyloxyresorufin and pentoxyresorufin 47-fold and 17-fold, respectively, but had little or no effect on short alkyl chains. 3MC-induction of microsomes increased dealkylation of all alkoxyresorufin ethers tested, preferentially dealkylating ethers with short alkyl chain in the order: methoxy > ethoxy > propoxy. Artemisia filifolia or Helenium flexuosum had no effect on basal hepatic cytochrome P450 content. However, microsomal dealkylation activity of short alkyl chain alkoxyresorufin ethers (methoxy, ethoxy and propoxy) was inhibited approximately 50%. When these plants are eaten for several days, they may inhibit biotransformation processes in herbivores through the same isoenzymes induced by 3MC.

Animal Feed↗
PubMed1996

The influence of ionophores on the duration of xylazine-ketamine anestheisa and the hepatic cytochrome P-450 content of broiler chickens.

This study examined the effects of feeding monensin, lasalocid or salinomycin (at 1x and 2x therapeutic levels for 20 d) on the duration of xylazine+ketamine sleep time and the hepatic cytochrome P-450 content in broiler chickens of different age groups (3- and 6-w-old). The 3-w-old birds fed 120 ppm salinomycin had a reduced xylazine+ketamine sleep time as compared to control (no drug). The 6-w birds had a sleep time similar to the controls. Associated with ionophore feeding was a trend toward P-450 induction when compared to controls. Increased P-450 content was statistically significant in the 3-w birds fed 90 ppm lasalocid and in the 6-w birds fed 200 ppm monensin. Ionophore administration above recommended levels gave conflicting results for duration of xylazine+ketamine sleep time and hepatic cytochrome P-450 levels. The isozymes of cytochrome P-450 responsible for xylazine and ketamine metabolism may be different from those induced by the ionophores. There was no significant age-related difference in ionophore effects on cytochrome P-450 content.

Analysis of Variance↗
PubMed1995

Mercury toxicosis caused by ingestion of a blistering compound in a horse.

Mercury toxicosis by ingestion was diagnosed in a 3-year-old Quarter Horse mare with a history of anorexia and signs of abdominal discomfort. Ten and 9 days prior to admission, an inorganic mercuric blistering agent has been applied for topical treatment of dorsal metacarpal disease. At referral, signs of depression, dependent edema, pollakiuria, nonproductive cough, and oral ulceration were noticed. Laboratory data were consistent with renal dysfunction. Mercury content of blood and urine was high, confirming the diagnosis. The horse responded to intensive care, consisting primarily of IV fluid treatment, and mercury-chelating agents. However, acute laminitis developed, and the owners elected to euthanatize the horse 18 days after mercury exposure. Necropsy findings included renal tubulonephrosis and ulcerative colitis and enteritis. Mercury concentration was highest in kidney and liver tissues. The potential for mercury toxicosis in horses currently exists, and although the prognosis is grave, some horses may recover with appropriate treatment and long-term supportive medical care.

Administration, Topical↗
PubMed1995

Protective effects of glucose-6-phosphate and NADP against alpha-chaconine-induced developmental toxicity in Xenopus embryos.

In previous studies a metabolic activation system (MAS) composed of Aroclor 1254-induced rat liver microsomes led to an apparent reduction of potato glycoalkaloid developmental toxicity in the frog embryo teratogenesis assay-Xenopus (FETAX). The reasons for this reduction were investigated in this study. The effect of the exogenous MAS on glycoalkaloid developmental toxicity was examined in two experiments in which a concentration series of alpha-chaconine was tested with a MAS with and without a reduced nicotinamide adenine dinucleotide (NADPH) generator system consisting of NADPH, oxidized nicotinamide adenine dinucleotide (NADP), glucose-6-phosphate (G6P) and glucose-6-phosphate dehydrogenase. The NADPH generator system and each of its individual components were tested at a single high concentration of alpha-chaconine to evaluate their potential effects on toxicity. The findings indicated that the protective effect of the MAS was not the result of detoxification by microsomal enzyme systems, but was caused by two components of the NADPH generator system, namely NADP and G6P. G6P was more protective of alpha-chaconine-induced toxicity than NADP at the concentrations tested. Thus, FETAX with a MAS must be performed with appropriate controls that take into account the possible interactions with individual components of the system.

Animals↗
PubMed1995

Hematological effects of 1,3,5-trinitrobenzene (TNB) in rats in vivo and in vitro.

We studied the hematological effects of single and repeated exposure to 1,3,5-trinitrobenzene (TNB) in rats. Male F-344 rats were gavaged with TNB at 35.5 and 71 mg/kg in corn oil. Blood was collected 5 h and 24 h after a single oral dose or 24 h after daily oral doses for 4 or 10 d in four different set of experiments. A dose-dependent methemoglobinemia was present only in blood collected 5 h after a single dose. A highly significant dose-dependent anemia with reduced red cells, hemoglobin, and hemotocrit was present in rats receiving TNB for 4 or 10 d. A dose-dependent decrease in serum triglycerides was present in rats receiving TNB for 10 d. There was no hemolysis when rat erythrocytes were incubated with TNB (in vitro) for 9 h. Spectral changes of hemoglobin recorded during the incubation with TNB confirm methemoglobin formation and progressive denaturation of hemoglobin-forming hemichromes. The significance of methemoglobin and hemichrome formation is discussed, and a probable hypothesis for the hemolytic anemia is suggested.

Anemia, Hemolytic↗
PubMed1995

Sensitivity of selected immunological, hematological, and reproductive parameters in the cotton rat (Sigmodon hispidus) to subchronic lead exposure.

The effect of lead exposure on cellular immunity, hematology, and reproductive and body condition in mature cotton rats (Sigmodon hispidus) was examined. Two groups of 36 cotton rats each were exposed to 0, 100, or 1,000 ppm lead in drinking water for either 7 or 13 weeks, between 31 August and 2 December 1990. Specific and non-specific cell-mediated immunity was assessed by measuring splenocyte proliferative responses to polyclonal mitogens (Concanavalin A and Pokeweed mitogen), in vivo 24-hr delayed-type hypersensitivity, metabolic activity of peritoneal macrophages, spleen mass and cellularity, and immune organ development. General physiological condition was assessed from hematological, morphological, and reproductive measures. Immune function was sensitive to lead exposure based on depressed proliferative responses of cultured splenocytes, smaller popliteal lymph nodes, and larger spleens among cotton rats receiving 1,000 ppm lead. Spleen mass was reduced in cotton rats receiving 100 ppm lead. Total leukocytes, lymphocytes, neutrophils, eosinophils, total splenocyte yield, packed cell volume, hemoglobin, and mean corpuscular hemoglobin were sensitive to lead exposure. Effects of lead exposure on general condition and reproductive parameters included reduced mass of liver, seminal vesicles, and epididymes in males following a 7-week exposure. Histopathologic changes reflected lead toxicity and included altered renal proximal tubular epithelium, renal intranuclear inclusions, and in some cases, lowered numbers of sperm and developing follicles. In general, lesions were more pronounced with increased lead concentration and longer exposure.

Adrenal Glands↗
PubMed1994

Cellular immune responses of nutritionally stressed juvenile cotton rats (Sigmodon hispidus) during acute benzene exposure.

Wild juvenile cotton rats (Sigmodon hispidus) were used in this study to examine the effects of exposure to cyclophosphamide (CY) or differing levels of benzene on selected measures of cellular immunity following dietary protein restriction. Benzene caused marginal immunotoxicity as indicated by suppressed splenocyte proliferation and total circulating neutrophils. Cyclophosphamide and also crude protein restriction induced severe immune lesions manifested as thymus and spleen atrophy, depressed delayed hypersensitivity response, reduced proliferative capacity of splenocytes, and reduced numbers of total leukocytes, lymphocytes, and splenocytes. Although severe immune modulation resulted from the individual effects of CY exposure and dietary protein restriction, there was little statistically significant toxicant-diet interaction.

Animals↗
PubMed1993

Calcification of the urinary bladder in the wild cotton rat (Sigmodon hispidus).

Calcification of the urinary bladder epithelium was observed in 19 of 30 and 18 of 30 wild cotton rats from control and petrochemical-contaminated sites, respectively. The rats in the two sites did not differ significantly in respect of serum calcium and phosphorus concentrations. The calcification was considered to be dystrophic in nature. An unidentified factor common to both control and petrochemical-contaminated sites was considered to be responsible for this syndrome.

Animals↗
PubMed1993

Spontaneous altered hepatocellular foci (AHF) in captive aged male cotton rats (Sigmodon hispidus).

Spontaneous altered hepatocellular foci (AHF) of basophilic type were observed in adult male cotton rats. The histological features of these foci were similar to those observed in Fischer 344 rats. However, an immunohistochemical technique with antibody to glutathione S-transferase placental form (GST-P) failed to stain these foci. Also normal bile ducts were not immunoreactive for GST-P. The presence of a gall bladder and of non-GST-P immunoreactive liver foci and bile ducts suggests that these cotton rats are phylogenetically closer to mice than rats.

Animals↗
PubMed1993

Cryptosporidiosis in a cotton rat (Sigmodon hispidus).

Cryptosporidiosis, previously unreported in cotton rats (Sigmodon hispidus), was observed in one of nine cotton rats from Pryor, Oklahoma (USA). Infection was confined to the large intestine. Microscopically, numerous cryptosporidians measuring 2 to 3 microns in diameter were intimately associated with the luminal surface of colonic and rectal mucosae. The affected lamina propria of the large intestine was diffusely infiltrated by eosinophils, lymphocytes and macrophages. Ultrastructurally, numerous trophozoites and a single schizont were observed. Microvilli were displaced by the presence of cryptosporidians at the attachment site.

Animals↗
PubMed1993

Effects of hepatic P-450 enzyme inhibitors and inducers on the duration of xylazine + ketamine anesthesia in broiler chickens and mice.

We previously showed that pretreatment with inhibitors of hepatic P-450 microsomal enzymes prolonged xylazine-ketamine anesthesia, which sometimes led to mortality in rats. In this study we determined if similar effects were produced in broiler chickens and mice. A combination of 5 mg xylazine/kg and 15 mg ketamine/kg im was given to broiler chickens 5-6 w of age, and a combination of 10 mg xylazine/kg and 200 mg ketamine/kg ip was given to mice. The loss of righting reflex was used to measure duration of anesthesia. Pretreatment with 100 mg chloramphenicol/kg im, 150 mg cimetidine/kg im, 25 mg SKF-525A/kg im or 40 mg ketoconazole/kg po significantly increased the duration of xylazine + ketamine anesthesia in the chickens. Pretreatment with 40 mg phenobarbital/kg im bid for 3 d, 25 mg 3-methylcholanthrene/kg im sid for 3 d, or 50 mg rifampin/kg im bid for 2 d failed to alter the duration of xylazine + ketamine anesthesia in the broilers. None of the inhibitors tested altered the duration of anesthesia in mice. Some chickens pretreated with inhibitors (cimetidine, ketoconazole, SKF-525A) or inducers (phenobarbital, 3-MC, rifampin) died. This study suggests that hepatic metabolism of xylazine may be similar in the rat and broiler chicken and that the pulmonary metabolism of xylazine and ketamine may be different in chickens and rats.

Anesthesia↗
PubMed1992

Cause-specific mortality of white-tailed deer as influenced by military training activities in southwestern Oklahoma.

Radio-telemetry was used to monitor movements and mortality of 56 white-tailed deer (Odocoileus virginianus) in response to intensive military training activities on West Range (18,000 ha), Fort Sill Military Reservation, Oklahoma. Cause-specific mortality was determined for 22 radio-collared deer, including adults (greater than or equal to 2.0-yr-old), yearlings (0.6-1.9-yr-old), and fawns (less than or equal to 75-day-old age group) from 1987 to 1989. Winter home ranges were largely confined to a 14,411 ha impact area centrally located on West Range. The mean annual mortality rate was 0.50 for adults and yearlings combined. Fifty percent of all adult and yearling mortality was attributed to military training activities, 28% to hunting, 16% to collisions with automobiles, and 6% to unknown causes. The mean monthly mortality rate was 0.61 for neonatal fawns and predation accounted for three of four mortalities. All captured deer in the greater than or equal to 2.6-yr-old, 82% in the 1.6-yr-old, 10% in the 0.6-yr-old, and all deer in the less than 7-day-old age groups were seropositive for bluetongue virus (BTV). Our study strongly suggests that the consequences of military training activities should be considered in the management of white-tailed deer herds on military installations.

Animals↗