Model systems for learning pediatric flexible bronchoscopy.

Considerable practice is necessary to develop the skills essential to successful and safe performance of flexible bronchoscopy, especially in pediatric patients. We review a number of model systems, both mechanical and living, for learning and maturing bronchoscopic skills. For each of the animal models (canine, feline, leporine, and simian), the relevant anatomy and anesthetic techniques as well as the relative advantages and disadvantages of each model are discussed.

Evaluation of a combination of tiletamine and zolazepam as an anesthetic for ferrets.

A combination of equal parts by weight of tiletamine hyrochloride and zolazepam hydrochloride was evaluated clinically in 12 adult male ferrets. Two dosage levels of 12 mg/kg and 22 mg/kg were evaluated. Both doses produced excellent immobilization, the length of which was dose dependent. However, only the higher dose consistently produced good muscle relaxation. Excessive pain upon infection was not noted nor was residual lameness evident. Electrocardiagraphically, notching of the QRS complex was noted at both doses. Anesthesia with poor analgesia occurred at the lower dose, while ferrets receiving the higher dose showed more variability in the degree of analgesia. It was concluded that this combination administered intramuscularly provided excellent immobilization, variable muscle relaxation and a generally smooth induction and recovery. At the higher dose, analgesia was adequate for minor surgical procedures of short duration.

Immunoreactive protein antigens of Mycoplasma pulmonis in experimentally infected rats.

Mycoplasma pulmonis was cultured in modified Hayflick's medium, washed in 0.25 M NaCl, and solubilized by 2.5% sodium dodecyl sulfate. Protein antigens of M pulmonis separated by polyacrylamide-gel electrophoresis were blotted onto nitrocellulose strips. Specific-pathogen-free rats were inoculated intranasally with M pulmonis. The serum samples of these rats were obtained periodically and used to react with fractionated M pulmonis antigens which were fixed on the nitrocellulose strips. The antigen-antibody reactions were further recognized by 125I-labeled antiglobulin. Detection of immunoreactive antigens was obtained by autoradiography. Antibody response was not detected in serum obtained 7 days after rats were inoculated, and by 14 days, a slight response to several proteins was found. At 28 days after rats were inoculated, many immunoreactive antigens were detected. Generally, antibodies against antigens of moderate to low molecular weight appeared early in the infection, and antibodies against antigens of high molecular weight appeared late. Important immunoreactive antigens thus identified can readily be distinguished from more than 58 different M pulmonis antigens detectable by sodium dodecyl sulfate polyacrylamide-gel electrophoresis. The humoral antibody response was measured by an enzyme-linked immunosorbent assay. The immunoglobulin G antibodies were initially detected at low level at 7 days after rats were inoculated. These humoral antibody responses reached maximum by 28 days. The increase in serum antibody titer corresponded with numbers of immunoreactive antigens detected by immunoradio-binding assay. The information gained by this investigation may improve our understanding of the antigenicity of M pulmonis and the immune response of rats exposed to M pulmonis.

Characterization of a Haemophilus sp. isolated from a rabbit with conjunctivitis.

A case of conjunctivitis in a rabbit caused by a Haemophilus sp. is described. This was the only organism that was isolated in large numbers from the infected eye. The uninfected eye of the same rabbit contained Staphylococcus epidermidis, Corynebacterium kutscheri, Proteus mirabilis and a Neisseria sp. Effects of infection with live Haemophilus sp. isolated from the subject rabbit was studied in the eyes of rabbits and mice. Swabbing live organisms in the normal rabbit eye produced blepharitis within 48 hours. Signs of blepharitis started to disappear after 10 days without treatment. No reaction was noted in the control eye (swabbed with sterile saline) of the rabbit. Swabbing live organisms or sterile saline in the normal mouse eye failed to produce visible lesions up to 4 weeks. Evidence suggests that the Haemophilus sp. was pathogenic for rabbits but not for mice.

Effects of dietary protein and ethanol intake on pregnant beagles fed purified diets.

Maternal weight gain of beagles was approximately 50% lower when ethanol was given twice daily at a dose of 1.8 g/kg body weight with either control protein (17% energy from protein) or low protein (8.5%) diet as compared to isocalorically sucrose-treated animals. Similarly, pup birth weights were about 27% lower from beagles given ethanol with either diet when compared to those from sucrose-treated bitches. Two weeks after beginning ethanol treatment, pregnant bitches fed either diet had higher hematocrit values and lower plasma concentrations of albumin and calcium as compared to sucrose-treated animals. Low dietary protein treatment, rather than ethanol, lowered maternal concentrations of red blood cell folate during pregnancy. As compared to sucrose-treated bitches, ethanol prevented folate levels in red blood cells from returning to the normal range by the 9th wk of pregnancy in animals fed low dietary protein. These data show that ethanol consumption and low dietary protein intake, independently of each other, significantly depress maternal weight gain, pup birth weight and some nutritionally related parameters of the mother.

Rabies induced in a cat by high-egg-passage Flury strain vaccine.

An adult male domestic short-hair cat developed posterior paralysis 22 days after being vaccinated for rabies with a high-egg-passage Flury strain vaccine currently approved for use in cats. A diagnosis of rabies was confirmed by mouse inoculations, and viral typing using a panel of monoclonal antibodies demonstrated that it was vaccine induced.

Choroid plexus, brain and kidney Na+,K+-ATPase: comparative activities in fetal, newborn and young adult rabbits.

We have studied maturation of brain barrier systems in fetal, newborn, juvenile and adult rabbits. We have compared choroid plexus and brain Na+,K+-ATPase levels in each age group, as well as serum and CSF Na+ concentration as a measure of the ability of the choroid plexus to generate a gradient from blood to CSF. The choroid plexus appears functionally mature at all ages studied, both in ability to produce a Na+ gradient and in ATPase levels. In contrast, brain ATPase levels rose markedly with age. Kidney ATPase measured for comparison showed a pattern similar to brain.

Failure of signs of physical dependence to develop in hamsters after prolonged consumption of large doses of ethanol.

Male Golden Hamsters drank large amounts of ethanol with food and water freely available, when ethanol was presented in water at concentrations of 10-40% (w/v). Although the hamsters consumed an average of 13.8 g/kg/day of ethanol for 3 months, no withdrawal signs were observed during 4 days without ethanol, nor were withdrawal signs observed during withdrawal after 4 more months of ethanol consumption. Although the Golden Hamster consumes large amounts of ethanol without the need for food or water deprivation, the Golden Hamsters may have limited usefulness as a model of physical dependence.