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Biomedical subjects

C Bailey

Publications and source records attributed to C Bailey.

At least 37 records · Page 2Linked to original sources

Shallow versus deep endotracheal suctioning in young rabbits: pathologic effects on the tracheobronchial wall.

The traditional technique for endotracheal suctioning of intubated neonates consists of inserting a catheter until resistance is met, withdrawing slightly, and applying suction. The extent of tissue damage caused by the traditional (deep) technique v that caused by an alternative shallow technique was studied with an animal model. Six 3-week-old rabbits were anesthetized, intubated, and suctioned every 15 minutes for six hours by neonatal intensive care unit nurses who were unaware of the study purpose. Three rabbits were suctioned by means of the deep technique, whereas the other three received shallow suctioning achieved by inserting the catheter no further than a premeasured distance. Light microscopy showed significantly increased necrosis and inflammation following deep suctioning. Electron microscopy revealed greater loss of cilia and increased mucus with the deep technique. To confirm our initial assumption that the deep technique is still used extensively by neonatal intensive care units throughout the country, a mail survey was conducted. Of the 405 (43%) neonatal intensive care unit physicians who responded, 82% reported frequent or exclusive use of the deep technique for routine suctioning. In this study, the fact that deep suctioning results in significantly more tracheobronchial pathology than does a shallow, premeasured technique is shown. It is recommended that nurseries change their current practice and adopt the shallow technique for routine suctioning of intubated neonates.

Animals

A new polymorphic marker of the T-cell antigen receptor alpha chain genes in man.

The restriction fragment length polymorphism of the unrearranged T-cell antigen receptor (Tcr) alpha chain gene was investigated. Taq I digests, when probed with a Tcr alpha chain cDNA probe, revealed polymorphic bands of 7.0, 2.0, and 1.4 kb, due to variations around the C alpha gene, and the V gene cluster. Family studies confirmed the segregation of these polymorphic bands as allelic markers. These polymorphisms provide a new marker for the analysis of genetic variation of the Tcr alpha chain, and the influence of variation of the Tcr genes on the immune response.

Alleles

Intermittent exposure of rats to 2450 MHz microwaves at 2.5 mW cm2: behavioral and physiological effects.

Long-Evans male adult rats were intermittently exposed for 14 weeks to continuous wave (CW) 2450-MHz microwaves at an average power density of 2.5 mW/cm2. The mean specific absorption rate was 0.70 W/kg (+/- 0.02 SEM). The rats were exposed 7 h/day, 7 days/week in a radiation chamber with a monopole above ground, while housed in Plexiglas cages. Weekly measures of body mass and food intake did not indicate statistically significant effects of microwave irradiation. Assessments of threshold for electric-footshock detection revealed a significant difference between microwave and sham-exposed animals. Assessments of cholinesterase and sulfhydryl groups in blood and 17-ketosteroids in urine did not distinguish the two groups of rats. Behavioral measures made at the end of the 14-week exposure included an open-field test, shuttlebox avoidance performance, and schedule-controlled lever-pressing for food pellets. Statistically significant differences between microwave- and sham-exposed rats were observed for these measures. Examination of adrenal tissue, plasma electrolytes, and organ masses after 14 weeks of exposure revealed no difference between the two groups of rats.

17-Ketosteroids

Relationship between childhood hyperactivity and accident proneness.

Previous research suggested that hyperactive children are especially susceptible to accidents. Two questions remain: is the relationship peculiar to hyperactivity in childhood or for behaviorally disturbed children in general and does the relationship hold for females as well as for males? To answer these questions 189 patients at a child psychiatric clinic were rated on a scale which included measures of hyperactivity and accident proneness. The hyperactive patients were more likely to be described as accident prone than nonhyperactive patients. The relationship between childhood hyperactivity and accident proneness is confirmed and is specific. The relationship holds for both boys and girls.

Accident Proneness

Breaking the ice.

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Burnout, Professional

Determination of proenkephalin products in brain tissue by high-performance liquid chromatography and a modified bioassay procedure.

A method is described for the separation of proenkephalin products using gradient high-performance liquid chromatography preceded by Sep-Pak chromatography. Samples can be assayed simply by use of a modified mouse vas deferens bioassay which is sufficiently sensitive for most applications. The preliminary Sep-Pak chromatography method excludes alpha-neoendorphin and the dynorphins and thus provides a suitable procedure for separation of prodynorphin and proenkephalin products.

Animals

Ontogenesis of proenkephalin products in rat striatum and the inhibitory effects of low-level lead exposure.

Certain developmental abnormalities have been associated with environmental exposure to lead and our previous studies have indicated that the endogenous opioid system is disrupted by this metal. In connection with this we report the ontogeny of proenkephalin products in the rat striatum determined by combined HPLC and bioassay and the effects of low-level lead exposure on this ontogeny. The development of Met-enkephalin levels was dissimilar from that of the other proenkephalin products, Met-enkephalyl-Arg6-Phe7, Met-enkephalyl-Arg6-Gly7-Leu8 and Leu-enkephalin. The ratios of Met-enkephalin containing peptides to Leu-enkephalin was less than the 6:1 ratio predicted from the proenkephalin structure. Lead (administered in the maternal drinking water, from conception to weaning at 100, 300 and 1000 ppm) caused a dose-related depression of the levels of proenkephalin products in rat striatum at 10, 21 and 30 days after birth. The most pronounced effects were observed at 10 days and the most persistent effects were seen with Met-enkephalin. Peak blood lead levels were below 45 micrograms/100 ml in the 100 and 300 ppm lead-dosed groups and in all lead-dosed groups at 10 days after birth. It is suggested that lead may have inhibitory effects on proenkephalin-processing enzymes.

Animals

Radiation myelitis following craniospinal irradiation with concurrent actinomycin-D therapy.

Two patients are presented who developed radiation myelitis as a complication of treatment for medulloblastoma. These patients had been entered onto a pilot study to evaluate the therapeutic efficacy of combined treatment with radiation therapy and actinomycin-D (AMD). AMD is a known radiation enhancer in all tissues but the nervous system. Both of these patients received a full course of cranio-spinal irradiation plus AMD 15 mcg/kg for the first five days of therapy. One patient developed myelitis at 4 months, and the other at 12 months after treatment. Both patients are surviving three years posttreatment without any evidence of recurrent disease. The myelitis in one patient has improved, and it is stable in the other patient. It is concluded that AMD enhances the effect of radiation therapy on the central nervous system. This has never been reported but is important to note now, since radiation enhancers are included in multimodal treatment regimens for a variety of malifnant conditions. Reduction of radiation dose may be necessary when large volumes of the nervous system are treated.

Adolescent

Systolic time intervals in monitoring for anthracycline cardiomyopathy in pediatric patients.

Systolic time intervals are of value in measuring left ventricular function. The ratio of the pre-ejection period to the left ventricular ejection time (PEP/LVET) was determined serially in 60 children with cancer receiving anthracycline drugs. Measurements were examined for their predictive value in determining incipient anthracycline cardiomyopathy. An increase in the PEP/LVET ratio was not followed by clinical failure in the majority of patients. Of two patients who developed presumed anthracycline cardiomyopathy, only one demonstrated an increase in the ratio prior to going into heart failure. The value of the PEP/LVET ratio in children for predicting anthracycline cardiomyopathy appears limited, based on the results of this study.

Adolescent