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Biomedical subjects

C M Lang

Publications and source records attributed to C M Lang.

At least 19 recordsLinked to original sources
PubMed1992

Antinociceptive properties of tiletamine-zolazepam improved by addition of xylazine or butorphanol.

A combination of tiletamine HCl and zolazepam HCl is frequently used as an anesthetic, but little is known about the antinociceptive properties of tiletamine-zolazepam. The antinociceptive properties of tiletamine-zolazepam alone or combined with xylazine or butorphanol were determined in the adult male rate using the tail-flick test. Changes in tail-flick latency were determined at 15, 45, and 75 min after IP drug administration of sterile water, sodium pentobarbital, morphine, tiletamine-zolazepam, xylazine, butorphanol, and tiletamine-zolazepam plus xylazine or butorphanol. Tail-flick latency approximated 100% maximum possible effect (MPE) at 15-75 min postinjection in morphine-treated rats. Tiletamine-zolazepam, xylazine, and butorphanol alone, at any dose utilized, produced less than 50% MPE. However, the combination of tiletamine-zolazepam with butorphanol or xylazine increased tail-flick latency approximately three times greater than tiletamine-zolazepam alone. These results demonstrate that: a) consonant with earlier findings, analgesia and anesthesia are independent states; b) tiletamine-zolazepam is not an effective combination with respect to analgesia; but c) in concert with appropriate drugs, it can exhibit potent antinociceptive properties.

Analgesics↗
PubMed1990

Cystitis, urolithiasis and cystic calculi in ageing guineapigs.

Nineteen cases of cystitis were diagnosed at necropsy and/or by histology in a group of 170 (96 females, 74 males) guineapigs (11.2%). Seventeen of the 19 cases (89.4%) were females. The mean age of guineapigs with cystitis was 34.7 months, which was higher than the mean age of 24 months of the 170 members of the study group. In addition, 6 cases of urolithiasis and cystic calculi in 5 females and one male were also found in the 170 guineapigs (3.5%). The mean age of the 6 cases was 30 months, which was also higher than the mean age of the 170 animals. The study suggests that aged female guineapigs were much more predisposed to cystitis and urolithiasis or cystic calculi than male and young guineapigs. The cause may be related to infection with Escherichia coli and Staphylococcus sp, cystic calculi, diabetes mellitus and female guineapig urogenital anatomy and function.

Aging↗
PubMed1990

An evaluation of three intravenous anesthetic regimens in New Zealand rabbits.

Intravenous anesthetics can be readily administered to rabbits through the marginal ear vein. In this study, three intravenous anesthetic protocols were evaluated in New Zealand White rabbits. The three anesthetic regimens were: (a) pentobarbital (40 mg/kg); (b) ketamine-xylazine (25-5 mg/kg); (c) midazolam-xylazine-alfentanil (1-1-0.1 mg/kg). The anesthetics were injected slowly over defined time intervals. Reactions to noxious stimuli were determined before and after administration of the anesthetics. Additionally, the effects of the anesthetic agents on the rabbit's cardiopulmonary system were evaluated. Rabbits anesthetized with midazolam-xylazine-alfentanil did not have a pedal withdrawal or ear pinch reflex throughout the testing period. The ketamine-xylazine combination produced a shorter duration of non-responsiveness to noxious stimuli. Rabbits anesthetized with pentobarbital had the greatest variability in response to noxious stimuli. Apnea occurred in at least one rabbit in each group. A side effect unique to the midazolam-xylazine-alfentanil group was the occurrence of opisthotonus or seizure activity during or shortly after the administration of alfentanil. Hypotension, hypercapnia and respiratory acidosis were characteristic of the cardiopulmonary effects of the anesthetics. When choosing an anesthetic regimen for rabbits, intravenous infusion should be considered as an option. Advantages include ease of administration, possibility of redosing as required, and minimal requirements for equipment. Disadvantages of intravenous anesthetic infusion in rabbits include potential for lethal overdose and metabolic alterations after administration.

Alfentanil↗
PubMed1990

Effect of in-house transport on murine plasma corticosterone concentration and blood lymphocyte populations.

The effect of in-house transport on plasma corticosterone concentration and blood lymphocyte populations of laboratory mice was investigated. Mice were transported within a research facility at 0900 hours in a pattern designed to simulate that commonly used by investigators prior to experimental manipulation. Plasma corticosterone concentration and WBC count were determined at 0.25, 2, 4, 8, 12, and 24 hours after transport. A significant (P less than 0.05) increase in plasma corticosterone concentration was seen in mice immediately after transport. The normal circadian rhythm of plasma corticosterone concentration was altered for the subsequent 24-hour period. Corresponding significant (P less than 0.05) decreases in total WBC numbers, lymphocyte count, and thymus gland weight were observed. The decrease in total blood lymphocyte numbers at 4 hours was reflected in B- and T-lymphocyte populations. The subsequent acute increase in plasma corticosterone concentration was associated with alterations in the cellular components of the immune system. Results of the study indicated that routine in-house transport of laboratory mice should be considered a stressful stimulus.

Animals↗
PubMed1989

Spontaneous reproductive tract leiomyomas in aged guinea-pigs.

Seven of 83 female guinea-pigs were found to have reproductive tract leiomyomas at necropsy. Sixty-three of these guinea-pigs also had cystic rete ovarii. Eleven separate leiomyomas were identified, the most common site of formation being the uterine body or horn. The tumours contained histological evidence of smooth muscle, abundant fibrous connective tissue and occasional foci of fibrocartilage and bone. Mitotic figures were identified in only one tumour. The mean age of guinea-pigs with leiomyomas was 47.6 months, and the mean age of the study population was 33.1 months. Two other reproductive tract tumours identified in the 83 guinea-pigs were an ovarian teratoma and a cavernous haemangioma. These data indicate that leiomyomas are the most common reproductive tract tumour in this colony of aged female guinea-pigs and that they are frequently seen in conjunction with cystic rete ovarii.

Aging↗
PubMed1989

Effectiveness of skin absorption of tincture of I in blocking radioiodine from the human thyroid gland.

Topical application of tincture of iodine (I) was found to be effective in blocking the thyroid uptake of orally administered 131I in humans. Abdominal skin application of tincture of I resulted in an approximately 82% reduction in the uptake of 131I by the thyroid gland. The effectiveness varied among individuals and may have depended on the quantity applied and on the application site. In each study group, elevated levels of serum I were observed.

Administration, Cutaneous↗
PubMed1989

Effect of cage population density on plasma corticosterone and peripheral lymphocyte populations of laboratory mice.

The effect of different population densities of mice per cage on plasma corticosterone, peripheral lymphocytes and specific lymphocyte subpopulations was investigated. The animals were housed in groups of 2, 4 or 8 mice per cage and the blood samples were taken from each animal of these groups on days one, 7 and 14. A significant elevation (P less than 0.05) in plasma corticosterone concentration was observed in the group of 8 mice per cage on days one and 7 as compared with those of 2 or 4 mice per cage. The number of peripheral lymphocytes was significantly decreased in the groups of 2 (P less than 0.01) and 8 (P less than 0.05) mice per cage as compared with the group of 4 mice per cage on day one. A significantly decreased number of lymphocytes (P less than 0.01) in the group of 8 mice per cage continued to day 7. There were no significant differences in specific lymphocyte subpopulations observed among these groups. The results of this study suggest that a population density of 4 mice per cage induced minimal stress compared to that induced by the population densities of 2 or 8 mice per cage. Since stress is known to induce alteration in a variety of biological functions, the population density of mice per cage should be considered in the interpretation of research data.

Animals↗
PubMed1989

Use of cage space by guineapigs.

Cage space requirements for laboratory animals have been established by Government Regulation and Recommendations. In order to test the adequacy of these space allocations, the use of cage floor area by breeding groups of guineapigs was studied. A computer-coupled video tracking system capable of imaging in low light intensity as well as total darkness was used to determine the average per cent occupancy by guineapigs in all portions of a cage over 12-h light and dark cycles. Simultaneous time synchronized slow motion video recordings permitted an analysis of activity to be coordinated with cage use data. Results of the study revealed that breeding groups of guineapigs utilize the periphery of the cage almost to the total exclusion of the centre of the cage. Approximately 75-85% of all occupancy in both the day and evening hours occurred in 47% of the cage floor area located along the periphery. Analysis of video recordings revealed that the animals remained active throughout the day and night with no prolonged period of quiescence that could be associated with sleep. Results of this study suggest that while guidelines for housing guineapigs based on area allocation per animal can be formulated and are easy to administer, they cannot be supported by the behavioural characteristics of these animals or careful quantitation of their pattern of cage space utilization.

Animals↗
PubMed1989

An evaluation of intra-cage ventilation in three animal caging systems.

Although temperature and relative humidity have been quantitated and their effects on research data studied, few studies have measured the air turnover rates at cage level. We evaluated the air distribution and air turnover rates in unoccupied shoe-box mouse cages, filter-top covered cages and shoe-box mouse cages housed in a flexible film isolator by using discontinuous gas chromatography/mass spectrometry and smoke. Results showed that air turnover was most rapid in the unoccupied shoe-box mouse cage and slowest in the filter-top covered cage. Placing mice in the filter-top covered cage did not significantly improve the air turnover rate. Although filter-top covered cages reduce cage-to-cage transmission of disease, the poor airflow observed within these cages could lead to a buildup of gaseous pollutants that may adversely affect the animal's health.

Air Conditioning↗
PubMed1988

Cilia-associated respiratory (CAR) bacillus infection of obese mice.

Cilia-associated respiratory (CAR) bacillus was identified in respiratory tract lesions of obese mice dying of chronic respiratory disease. Neither Mycoplasma pulmonis nor pathogenic bacteria were isolated from cultures of the lesions at necropsy, but there was serologic and histologic evidence of respiratory virus infection. Cranial-ventral areas of lung were firm and demarcated from unaffected lung at gross examination, and representative tissue sank in water. Microscopically, there was suppurative bronchopneumonia with extensive peribronchiole lymphocyte and plasma cell proliferation. The affected bronchiole epithelium was covered with a sheet of slightly basophilic, filamentous, gram negative bacteria. Bronchioles with lesser amounts of lymphocyte accumulations contained lesser amounts of filamentous bacteria. Bronchioles without filamentous bacteria lining the respiratory epithelium lacked peribronchiole lymphocyte accumulations. There was a high correlation between CAR bacillus-positive serology and the identification of diagnostic histologic lesions. CAR bacillus was readily stained using immunohistochemical methods, and the ultrastructural features were similar to that described in rat infections.

Animals↗
PubMed1988

Hazards of urethane (ethyl carbamate): a review of the literature.

Urethane (ethyl carbamate) is used alone or in combination with other drugs to produce anaesthesia in laboratory animals. Although originally studied as a potential phytocide, urethane demonstrated antineoplastic properties when administered to rats with the Walker rat carcinoma 256. Subsequent trials in humans led to its use as a chemotherapeutic agent for various leukaemias. Mice develop pulmonary adenomas earlier in life and at a higher incidence following urethane administration. Urethane's carcinogenic influence is greater in neonatal mice; it also has a transplacental influence in mice. In rats, urethane increases the incidence of pulmonary adenomas, Zymbal Gland tumours, and a variety of other neoplasms. Urethane is absorbed sufficiently from the skin of laboratory animals to produce a transient narcosis. The carcinogenic effect appears to be due to an undefined oncogenic intermediate formed in the blood. Considering the properties urethane demonstrates in animals, the safety of its use by laboratory personnel is in question. However, if appropriate guidelines are followed, urethane should continue to be a useful anaesthetic agent for laboratory animals.

Adenoma↗
PubMed1988

An evaluation of three anaesthetic regimes in the gray short-tailed opossum (Monodelphis domestica).

The effect of several anaesthetic agents on the gray short-tailed opossum (Monodelphis domestica) was investigated. Pentobarbitone sodium at a dose of 50 mg/kg sedated the animals but did not produce analgesia or anaesthesia. A combination of ketamine hydrochloride and xylazine at 40 mg/kg and 5 mg/kg, respectively, sedated the animals, but anaesthetic levels were not attained. Halothane was most effective in producing anaesthesia in Monodelphis domestica. Hypothermia was a major side effect with all three anaesthetic regimes.

Anesthesia↗
PubMed1988

An evaluation of analgesia associated with the immobility response in laboratory rabbits.

The immobility response (IR) was studied in rabbits to evaluate its analgesic properties and reliability as a method of restraint. The participation of the endogenous opioid system in IR was studied indirectly by evaluating the effects of the narcotic antagonist naloxone on this phenomenon. Twenty-four adult New Zealand White rabbits were subjected to six noxious stimuli while restrained by IR and while restrained under control conditions. Testing on each animal was repeated under both conditions following the administration of naloxone. The noxious stimuli consisted of three levels of electric shock (10 volts, 30 volts, and 50 volts) applied to the shaved forearm, and mechanical pressure applied to the pinna, front toe, and hind toe. Withdrawal and changes in blood pressure, heart rate, and respiration were used as indicators of pain perception. Distress associated with noxious electrical and pressure stimulation was significantly reduced by IR, which suggested that the phenomenon does have a significant analgesic component. However, the rabbits showed wide variability in their susceptibility to IR induction, and even animals which did not withdraw in response to noxious stimulation under IR sometimes exhibited physiological changes suggestive of distress. Therefore, IR should not be considered as a reliable or humane alternative to analgesic/anesthetic drugs for laboratory rabbits. Naloxone had little effect on IR or IR-associated analgesia.

Analgesia↗
PubMed1987

Reproductive failure associated with cystic rete ovarii in guinea pigs.

Cystic ovaries were found at necropsy in 54 of 71 (76%) female guinea pigs between 18 and 60 months of age. Histologic appearance and location of the cysts within the ovary were consistent with cystic rete ovarii. Microscopic appearance of the large ovarian cysts suggested reproductive performance in these guinea pigs should be compromised. Breeding records indicated that fertility was markedly reduced in affected females over fifteen months of age. Cystic endometrial hyperplasia, mucometra, endometritis in appropriate placental tissue, or fibroleiomyomas were seen in 21 of 54 (39%) guinea pigs with cystic ovaries, but in only one of 17 (6%) guinea pigs without cystic ovaries.

Age Factors↗
PubMed1987

The effects of pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam on arterial blood pH, blood gases, mean arterial blood pressure and heart rate in adult male rats.

Although anesthetics are known to cause respiratory and cardiovascular depression in humans, these adverse effects rarely have been investigated in laboratory rodents. This study evaluated the effects of four different injectable drugs, pentobarbital, fentanyl-droperidol (Innovar-Vet), ketamine-xylazine and ketamine-diazepam on the respiratory and cardiovascular systems of rats. Results showed marked acidosis, hypercarbia and hypoxia with high doses of Innovar-Vet, moderate respiratory depression with all dosages of pentobarbital and minimal respiratory depression with ketamine-xylazine and ketamine-diazepam. Innovar-Vet, ketamine-xylazine and pentobarbital caused profound hypotension, particularly at high dosages, while ketamine-diazepam caused the least depression in mean arterial blood pressure of all drugs evaluated. None of the drugs studied produced significant alterations in heart rate. Throughout all dosages investigated, the ketamine-diazepam combination showed the least overall effects on ventilation and perfusion of the four parenteral drug combinations studied.

Analgesics↗
PubMed1987

A comparison of pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam anesthesia in adult male rats.

Proper use of anesthetics is of paramount importance for humane animal care. Current research trends show a greater reliance on rats for laboratory investigations. This study compared several dosages for four different drugs, (pentobarbital, fentanyl-droperidol, ketamine-xylazine and ketamine-diazepam) for use in the laboratory rat. Each drug was evaluated in respect to its onset, duration of effect, recovery, adverse effects and mortality. A quantitative assessment of the depth of anesthesia also was obtained for all dosages of each drug. Results showed that all tested dosages of pentobarbital, ketamine-xylazine and ketamine-diazepam were suitable anesthetics for use in the laboratory rat. Low dosages of fentanyl-droperidol (Innovar-Vet), however, appeared to produce a state known as neuroleptanalgesia as opposed to anesthesia seen with the other agents.

Anesthesia, General↗