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Biomedical subjects

M Callahan

Publications and source records attributed to M Callahan.

At least 37 records · Page 2Linked to original sources
PubMed1990

Physiological and behavioral responses of gray wolves (Canis lupus) to immobilization with tiletamine and zolazepam.

We conducted a series of experiments to examine the efficacy of Telazol (TEL) for immobilization of captive gray wolves (Canis lupus). Ten wolves were immobilized with either 5 or 10 mg/kg TEL. There was no difference in induction time (6.5 +/- 0.8 versus 5.8 +/- 1.2 min; P = 0.63) between the two doses, but the time to initial arousal was longer for the higher dose (P = 0.0008). Wolves were again immobilized with 10 mg/kg TEL and upon initial arousal were given additional doses of either 5.0 mg/kg TEL or 2.5 mg/kg ketamine (KET) to maintain immobilization. Wolves given boosters of TEL had longer second recovery times than wolves given KET (P = 0.01). There were no differences in induction times or arousal times for wolves immobilized with TEL that had been reconstituted with sterile water and stored at 20 C for 30 days (P greater than or equal to 0.11) or 60 days (P greater than or equal to 0.27) when compared to immobilization times using fresh solution. Induction times for wolves given TEL reconstituted with water and propylene glycol and stored for 60 days at -9 C were longer (P less than 0.05) than such times for wolves given standard TEL, but time to initial arousal was unchanged (P greater than or equal to 0.44). There were no differences in heart rates (P = 0.36), blood pressures (P = 0.32), respiratory rates (P = 0.91), and rectal temperatures (P = 0.62) between the two TEL doses. Telazol was shown to be an effective and safe immobilizing agent for gray wolves.

Animals↗
PubMed1990

Physiological responses of red foxes (Vulpes vulpes) to surgery.

Radio transmitters were surgically implanted into the abdomens of red foxes (Vulpes vulpes). Blood samples were taken before, immediately after, and 8 hr after surgery and analyzed for hormonal, biochemical, electrolyte and hematologic changes. Samples were taken at the same times from control foxes. Adrenocorticotropin increased after surgery (P less than 0.05), but returned to pre-surgery values after 8 hr. Cortisol increased and remained elevated in the surgery group relative to pre-surgery values or to control values (P less than 0.05); Triiodothyronine and thyroxine both decreased from post-surgery values 8 hr later (P less than 0.05). Creatine kinase, total bilirubin and aspartate aminotransferase increased after 8 hr in both surgery and control groups (P less than 0.05). Carbon dioxide increased under anesthesia in both groups, but returned to initial values after 8 hr (P less than 0.05). The white blood cell count increased after 8 hr only in the surgery group (P less than 0.05). There were no differences between the groups for any value obtained from the initial blood sample. These data indicate that abdominal surgery results in prolonged adrenocortical activity and decreased thyroid hormone levels, but otherwise has minimal systemic effects in red foxes.

Adrenocorticotropic Hormone↗
PubMed1989

Physiological response of gray wolves to butorphanol-xylazine immobilization and antagonism by naloxone and yohimbine.

Captive gray wolves (Canis lupus) were immobilized (loss of consciousness) with 2.0 mg/kg xylazine hydrochloride (XYL) and 0.4 mg/kg butorphanol tartrate (BUT) administered intramuscularly. Induction time was 11.8 +/- 0.8 min (mean +/- SE). Immobilization resulted in bradycardia, respiratory depression, and normotension. Fifteen min after induction, six wolves were given either 0.05 mg/kg naloxone hydrochloride (NAL) and 0.125 or 0.250 mg/kg yohimbine hydrochloride (YOH), or an equal volume of saline (control) intravenously. Antagonism resulted in shortened recovery times compared to control animals (P less than 0.03); there was no difference in recovery times between the YOH doses (P greater than 0.05). Antagonism caused increases in heart rate (HR) and respiratory rate (RR), but no changes in MABP. Eight other wolves were similarly immobilized, but given only NAL. This resulted in partial antagonism with the animals appearing to be sedated with XYL only. Three wolves given only 0.4 mg/kg BUT assumed a state described as "apathetic sedation." Three other wolves sedated with only 2.0 mg/kg XYL showed a profound sedation characterized by recumbency, bradycardia and shallow, but regular, respiration. This study demonstrated that (1) BUT and XYL together, but not separately, can completely immobilize wolves, (2) this combination can be rapidly antagonized by NAL and YOH, and (3) there appeared to be no adverse cardiopulmonary reactions to any of the drugs used.

Animals↗
PubMed1988

Use of xylazine sedation with yohimbine antagonism in captive gray wolves.

Captive gray wolves (Canis lupus) were given 2.2 mg/kg xylazine hydrochloride intramuscularly resulting in profound sedation in 9.1 +/- 0.6 min (mean +/- SE). Heart rate was 42.0 +/- 1.0 beats per minute and respiratory rate was 20.1 +/- 1.6 respirations per minute during sedation. A variety of manipulations could be performed on sedated animals in relative safety. Thirty min after xylazine administration, the animals were given either 0.15 mg/kg yohimbine hydrochloride or 5% dextrose solution intravenously causing recovery in 5.3 +/- 1.0 and 97.1 +/- 14.0 min, respectively (P less than 0.001).

Animal Husbandry↗
PubMed1987

Granulocytic sarcoma presenting as pulmonary nodules and lymphadenopathy.

A patient presented with anterior and posterior cervical lymphadenopathy as well as widespread intrapulmonary nodules. Histologic sections of both lymph node and lung revealed dense infiltration by sheets of cells which were cytochemically positive for chloroacetate esterase and myeloperoxidase, thus suggesting a diagnosis of granulocytic sarcoma. The patient was initially treated with daily hydroxyurea. After 6 weeks, when progression of the disease was apparent, hydroxyurea was discontinued and the patient was placed on mithramycin, an agent reported to induce differentiation of myeloid precursor cells both in vitro and in vivo. On this latter agent, a dramatic response has been noted with a decrease in the pulmonary symptoms, and a marked reduction in the size of the lymph nodes and lung nodules. The authors report this case because it represents a rare presentation of an uncommon disease and because of the striking improvement that followed the initiation of a novel therapeutic modality.

Aged↗
PubMed1987

Cardiovascular and behavioral responses of gray wolves to ketamine-xylazine immobilization and antagonism by yohimbine.

Adult wolves (Canis lupus) were immobilized with 6.6 mg/kg ketamine hydrochloride (KET) and 2.2 mg/kg xylazine hydrochloride (XYL) administered intramuscularly. Induction time was 4.6 +/- 0.3 min (mean +/- SE). Immobilization resulted in significant bradycardia and hypertension (P less than 0.05). Twenty min after induction, the wolves were given 0.05-0.60 mg/kg yohimbine hydrochloride (YOH). Yohimbine given intravenously produced dose-related increases in heart rate (HR) with doses greater than 0.15 mg/kg resulting in extreme tachycardia (greater than 300 bpm). All doses of YOH caused a temporary decrease in mean arterial blood pressure (MABP) with some individual animals manifesting profound hypotension (less than 30 torr) at doses greater than 0.15 mg/kg. Increasing the dose of YOH above 0.15 mg/kg did not significantly decrease either arousal or ambulation times. Administering YOH at 40 or 60 min after induction resulted in decreased arousal and ambulation times. Stimulation by weighing and taking repeated blood samples during anesthesia did not shorten arousal times. We recommend that wolves immobilized with XYL-KET be antagonized with doses of YOH less than 0.15 mg/kg.

Animals↗
PubMed1985

The PDGF-inducible 'competence genes': intracellular mediators of the mitogenic response.

We have described a new gene family within mammalian cells. Transcription of this gene family is coordinately induced when BALB/c-3T3 cells are exposed to platelet-derived growth factor. At least two cellular proto-oncogenes (c-myc and c-fos) are members of this gene family, which we term 'competence'. At least one competence gene, c-myc, functions as an intracellular mediator of the mitogenic response to PDGF. Expression of the competence gene family may be a central component of the mitogenic response in fibroblasts, lymphocytes and regenerating liver.

Animals↗
PubMed1985

Sheep consumption: a possible source of spongiform encephalopathy in humans.

A fatal spongiform encephalopathy of sheep and goats (scrapie) shares many characteristics with Creutzfeldt-Jakob disease (CJD), a similar dementing illness of humans. To investigate the possibility that CJD is acquired by ingestion of contaminated sheep products, we collected information on production, slaughtering practices, and marketing of sheep in Pennsylvania. The study revealed that sheep were usually marketed before central nervous system signs of scrapie are expected to appear; breeds known to be susceptible to the disease were the most common breeds raised in the area; sheep were imported from other states including those with a high frequency of scrapie; use of veterinary services on the sheep farms investigated and, hence, opportunities to detect the disease were limited; sheep producers in the area knew little about scrapie despite the fact that the disease has been reported in the area, and animal organs including sheep organs were sometimes included in processed food. Therefore, it was concluded that in Pennsylvania there are some 'weak links' through which scrapie-infected animals could contaminate human food, and that consumption of these foods could perhaps account for spongiform encephalopathy in humans. The weak links observed are probably not unique to Pennsylvania.

Abattoirs↗
PubMed1983

L-glutamine D-fructose-6-P aminotransferase regulation by glucose-6-P and UDP-N-acetylglucosamine.

L-Glutamine D-Fructose-6-P aminotransferase regulates hexosamine synthesis. An affinity purified human fibroblast aminotransferase and specific radioisotope assays developed by us were used to show an independent inhibition of the aminotransferase by Glucose-6-P. More interestingly, at concentration of UDP-N-Acetylglucosamine and glucose-6-P where either sugar has no independent inhibitory effect, there is an allosteric and significant inhibition of the aminotransferase.

Allosteric Regulation↗