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Biomedical subjects

R F Taylor

Publications and source records attributed to R F Taylor.

At least 55 records · Page 3Linked to original sources
PubMed1986

Methods of euthanasia in poultry and food-producing animals.

This article summarizes the methods of euthanasia in poultry and food-producing animals and details some of the advantages and disadvantages of specific methods. Specific recommendations are made for each type of animal, with alternative methods for special circumstances. Reasons are given for recommending methods that are not "first-choice methods" of the AVMA Panel on Euthanasia. Detailed descriptions are included for selected methods of euthanasia.

Amides↗
PubMed1986

Effect of nicotine and acetylcholine on crustacean muscle membrane potential.

We have investigated the effect of nicotine and acetylcholine on the resting membrane potential of the crayfish extensor muscle in order to determine whether crustacean muscle can be activated by cholinergic compounds. Intracellular recordings from individual deep extensor abdominal muscle cells were made using standard glass microelectrode techniques. The resting membrane potential was measured before and after treatment with glutamate, nicotine, and acetylcholine. Glutamate, which is a known activator of crayfish muscle, was used to determine whether the muscle cell preparation was viable and capable of responding to any of the test substances. Our results confirm that application of glutamate is associated with a depolarization of the muscle membrane. However, muscle cells showed no depolarization after treatment with nicotine (50 microM) or acetylcholine (66 microM). These results argue against the notion that increases in muscle tension may be responsible for the increased receptor organ discharge observed in the presence of nicotine. Rather, it supports the hypothesis that nicotine is acting directly on the mechanoreceptor membrane to change its sensitivity.

Acetylcholine↗
PubMed1985

Disease patterns in the Detroit Zoo: a study of the avian population from 1973 through 1983.

A retrospective study was conducted to evaluate disease patterns in birds at the Detroit Zoo from 1973 through 1983. Data were derived from the zoo's medical and animal census records; the mean (+/- SD) population of birds during the study period was 469 +/- 42. Overall annual morbidity rates were 12.5% to 21.5%, with spring months having the highest morbidity rates. Annual mortality rates were 3.1% to 15.2%; 23.9% of the deaths were caused by microbial agents (particularly Erysipelothrix rhusiopathiae, hemolytic Escherichia coli, Salmonella spp, Aeromonas spp and Proteus spp), 15.4% by trauma, and 42.5% by nondetermined causes. The mute swan (Cygnus olor), mallard duck (Anas platyrhynchos), common gallinule (Gallinula chloropus), common rhea (Rhea americana), and red-billed hornbill (Tockus erythrorhynchus) were the 5 species most frequently affected of the 1,032 deaths from 1973 through 1983. The most frequently isolated parasites were Microtetramere spp, coccidian species, Diplotriaena spp, and Trichomonia spp.

Animals↗
PubMed1985

Disease patterns in the Detroit Zoo: a study of reptilian and amphibian populations from 1973 through 1983.

A retrospective study was conducted to determine disease patterns in reptilian and amphibian populations at the Detroit Zoo from 1973 through 1983. In the reptilian population (mean +/- SD = 285.2 +/- 28), overall annual mortality rates were 1% to 40%. Mortality rates were highest in the fall months (20%) and lowest in the winter months (6%). The most frequently affected reptiles were iguana (Iguana iguana), reticulated python (Python reticulatus), rattlesnakes (Crotalus spp), common boa (Constrictor constrictor), and lizards (various genera of suborder Lacertilia). Of the 1,300 reptilian deaths from 1973 through 1983, 36.6% were caused by microbial agents, 12% by parasites, 11.6% by trauma, and 9.3% by nutritional deficiencies. The main microbial organisms that caused death were Aeromonas spp, Salmonella spp, Pseudomonas spp, Proteus spp, and Edwardsiella spp. The main parasites that caused death were Entamoeba spp and lungworms. Among amphibians, frogs and toads were the most frequently affected, and starvation and trauma were the most frequent causes of death.

Amphibians↗
PubMed1985

Disease patterns in the Detroit Zoo: a study of the mammalian population from 1973 through 1983.

A retrospective study was conducted to evaluate disease patterns in the mammals at the Detroit Zoo from 1973 through 1983. The reindeer (Rangifer tarandus), common eland (Taurotragus oryx), rednecked Wallaby (Protemnodon rufogrisea), sitatunga (Tragelaphus spekii), and kangaroo (Macropus spp)- were the most frequently affected mammalian species. Parasitic agents (80% of which were internal parasites) caused morbidity in 60.2% of the mammals evaluated (n = 2,475) and microbial agents caused morbidity in 20.8% of the animals. Strongyloides spp, Trichostrongylus spp, coccidian species, Diphyllobothrium spp, and Trichuris spp were the internal parasites most frequently found. Overall annual mortality rate was 14% to 34%, with microbiological agents causing the highest mortality (26.5%). Pasteurella spp, beta-hemolytic Streptococcus spp, pathogenic Escherichia coli, Corynebacterium spp, and Klebsiella pneumoniae were the most frequent microbial causes of death. Cause of mortality could not be determined in 21.5% of the animals evaluated. The percentage of animals successfully treated increased from 1973 through 1983. Generally, however, the percentage of successfully treated animals was low (21% to 39%).

Animal Diseases↗
PubMed1985

Static lung compliance during the development of the bullfrog, Rana catesbeiana.

The static compliance of excised lungs was measured during the metamorphic development of the bullfrog, Rana catesbeiana. Absolute static compliance of excised lungs increased with developmental stage from 0.02(+/- 0.01 SD) ml/cm H2O at Taylor-Kollros (TK) stage III to 34.67(+/- 15.00 SD) ml/cm H2O for adults. When static lung compliance was standardized by dividing by the lung volume at 4 cm H2O transmural pressure (approximately maximal capacity), lung compliance was relatively constant during early development and increased at the onset of metamorphic climax (TK stage XX). Although the absolute lung compliances of developing tadpoles are small, the volume-specific compliances are three to four times greater than those of some mammals. The compliance-independent index of hysteresis also increased during development from 0.0008(+/- 0.0006 SD) cm at TK stage V to 1.36(+/- 1.21 SD) cm for adults suggesting increases in pulmonary structural complexity and/or an increase in the production and secretion of a pulmonary surfactant-like substance. These developmental changes in pulmonary compliance and hysteresis mirror the increasing utility of the lung for gas exchange during the metamorphosis of the bullfrog.

Animals↗
PubMed1985

Chemosensitivity of crayfish slowly adapting stretch receptors to nicotine.

It has recently been demonstrated that slowly adapting stretch receptors (SASRs) in the airways of the dog respond directly to nicotine (Federation Proc. 43: 318, 1984). The purpose of the present experiment was to investigate this chemical effect on an isolated stretch receptor. The crayfish muscle receptor organ was chosen, since crayfish muscle is reported to be insensitive to nicotine or acetylcholine and therefore permits the testing of any direct chemical effect of nicotine on the muscle stretch receptors. The tail was removed and pinned out in a tissue bath, and a stretch receptor organ was surgically isolated. Single-unit SASR extracellular nerve recordings were made while simultaneously measuring tension in the tail. Drugs were prepared in Van Harreveld's solution and administered into the bath kept at 18 degrees C. When resting muscle tension was essentially reduced to zero by cutting both ends of the receptor organ muscle, nicotine (0.07 microM) added to the bath increased receptor activity fourfold. This response was abolished by treatment with hexamethonium (690 microM). In a second group of animals in which the muscle was left intact, nicotine was shown to significantly increase receptor sensitivity to step changes in muscle tension. Once again hexamethonium blocked the response to nicotine. These results demonstrate that the sensitivity of mechanoreceptor can be altered by chemical interaction with nicotinic receptors, which dramatically alter sensory receptor activity.

Animals↗
PubMed1985

The role of neutrophil membrane glycoprotein GP-150 in neutrophil adherence to endothelium in vitro.

We have previously described two patients with a congenital defect in neutrophil function characterized by an inability to form pus. The patients' neutrophils lack a membrane glycoprotein of mol wt 150,000 daltons (GP-150) on analysis by SDS-PAGE. This glycoprotein is part of a membrane antigen complex recognized by the murine monoclonal antibody (MoAb) 60.3. Addition of MoAb 60.3 to normal neutrophils produces defects in chemotaxis and phagocytosis in vitro similar to those observed in the patients. Since neutrophil adherence to vascular endothelium is prerequisite to neutrophil emigration in vivo, we examined the interaction of the patients' neutrophils and normal neutrophils treated with MoAb 60.3 with cultured endothelium. Adherence was determined as the percentage of 51Cr-labeled purified peripheral blood neutrophils which remained adherent to plastic wells or endothelial monolayers after a 45-minute incubation at 37 degrees C. The percentage of neutrophils from patient 1 remaining adherent to uncoated, fibronectin-coated, or laminin-coated plastic was similar to that observed in normal neutrophils (55% to 84% adherence with normal neutrophils v 73% to 78% adherence with the patient's neutrophils and 63% to 82% adherence with MoAb 60.3-treated normal neutrophils). The adherence of the neutrophils from patient 1 and MoAb 60.3-treated normal neutrophils to human or bovine endothelium in serum-free medium was also not significantly different from that observed in normal neutrophils (less than 10% adherence with normal, MoAb 60.3-treated, and patient neutrophils). In medium containing 10% autologous or heterologous human plasma, however, the adherence of neutrophils from patient 1 or MoAb 60.3-treated normal neutrophils to endothelial monolayers was significantly reduced (35% +/- 7% of normal neutrophils in seven experiments). Although phorbol myristate acetate (PMA) (10 ng/mL) and calcium ionophore A23187 (10(-5) mol/L) markedly increased the adherence of normal neutrophils to endothelial monolayers in serum-free medium (40% to 85% adherence), neither agent increased the adherence of the neutrophils from patient 1 or normal neutrophils treated with MoAb 60.3 (less than 5% adherence). The adherence of PMA-activated neutrophils from patient 2 to endothelial monolayers was also markedly decreased when compared with that of normal neutrophils. Postsecretory cell-free supernatants from PMA-activated normal neutrophils failed to augment adherence of neutrophils from patient 1 (less than 5% adherence).(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1984

Comparison of low- and high-pressure affinity chromatography for the purification of serine and sulfhydryl esterases.

A series of affinity chromatography packings for the purification of serine and sulfhydryl esterases (acetylcholinesterase, alkaline phosphatase, urokinase and papain) have been synthesized using commercially available agarose, glass and acrylate parent matrices. Two ligands were coupled to the matrices by utilizing carbodiimide or reaction with active groups already present on the matrix: the quaternary ammonium compound trimethyl(p-aminophenyl)ammonium chloride and the serine esterase inhibitor analog p-aminobenzamidine. It was found that enzyme purification on the agarose- or acrylate-based packings was most successful, resulting in as much as fifty-fold purification over starting material. The pressure stability of the acrylate packing allowed purification by high-pressure affinity chromatography and decreased purification times as much as six-fold in comparison to agarose columns.

Acetylcholinesterase↗
PubMed1984

Absence of monoclonal-antibody-defined protein complex in boy with abnormal leucocyte function.

An 8-year-old boy with severe recurrent bacterial infections was found to lack the cell-surface multimeric polypeptide complex defined by murine monoclonal antibody 60.3. This complex is expressed on the surface of all normal polymorphonuclear leucocytes (PMN), monocytes, and lymphocytes. Incubation of normal lymphocytes or PMN with antibody 60.3 produced functional abnormalities comparable with those observed in the patient's cells, suggesting that the polypeptide complex plays a significant part in several membrane-dependent leucocyte functions.

Antibodies, Monoclonal↗
PubMed1984

Platelet activation caused by cardiac catheter blood collection, and its prevention.

The study of platelet changes occurring across the coronary circulation is important in the investigation of the platelet's role in ischemic heart disease. It requires blood sampling through cardiac catheters. This could activate platelets and alter the results of tests of platelet activation and reactivity. This study was designed to examine this problem and to devise satisfactory methods for obtaining blood for platelet studies through long catheters. Blood collected through catheters introduced with a guide-wire had a much higher plasma heparin neutralising activity (HNA), platelet factor 4(PF4) and beta-thromboglobulin (beta TG) than peripheral venous blood, and lower platelet count(PC). Blood collected through catheters introduced via a sheath, and kept filled with anticoagulant/antiplatelet solution until blood sampling, gave results similar to peripheral venous blood for the PC, platelet aggregate ratio, platelet fluorescent granule count, and for plasma HNA, PF4 and beta TG. It is concluded that platelets are activated during blood collection through cardiac catheters; however, with appropriate precautions, blood which is satisfactory for platelet studies can be obtained.

Adolescent↗
PubMed1984

Control of hemodynamic adjustments during acute volume expansion in the rabbit.

The influence of reflexes mediated by the carotid sinus, aortic, and vagus nerves on control of blood pressure were investigated in the pentobarbital-anesthetized rabbit during an acute intravascular volume expansion. Blood, kept at 37 degrees C, was gradually infused at 2.5-min intervals until the blood volume of each animal was expanded to 10, 20, 30, and 40% above normal. Responses in sinoaortic-vagally denervated rabbits were compared to intact rabbits. Both intact and denervated animals showed a significant increase in central venous pressure with each 10% addition of blood. Heart rate did fall significantly in the intact group but not in the denervated group. No significant changes were identified in mean arterial pressure (MAP) in either group. In both groups changes in cardiac output were significantly greater than control for 20, 30, and 40% expansion and calculated total peripheral resistance fell in both groups at all levels of expansion when compared to control. The absence of significant changes in MAP within the intact and denervated groups suggests that sinoaortic-vagal reflexes are not affecting control of MAP in response to slow, acute volume expansion in the intact rabbit. On the other hand, since total peripheral resistance fell in both groups, a non-sinoaortic-vagal mechanism appears to be functional. This mechanism may assist in increasing vascular capacitance in order to prevent significant increases in blood pressure.

Animals↗