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B Healy

Publications and source records attributed to B Healy.

At least 37 records · Page 2Linked to original sources

Bradycardia induced from stimulation of the left versus right central nucleus of the amygdala.

Studies have demonstrated that the predominant effect of stimulation of the central nucleus of the amygdala is one of heart rate deceleration. Anatomical studies have shown that projections from the central nucleus to the cardioinhibitory neurons in the medulla are ipsilateral and that projections of the left or right vagal efferents to the heart innervate different nodal points. The results of this study suggest that stimulation of the central nucleus of the amygdala from either the left or right hemisphere produced similar increases in heart period. These results are discussed in terms of the effects of the localization of epileptic foci in the temporal lobes on the cardiovascular system.

Amygdala↗

The effect of amygdaloid kindling on heart period and heart period variability.

Two studies were conducted on rats to assess the effects of amygdaloid kindling on baseline measures of heart period and heart period variance. The results indicate that seizure activity was associated with increased vagal influence on heart period marked by sinus bradycardia and decreased beat-to-beat variability. The resultant bradycardia was enhanced following each seizure and persisted for at least a one-week period of time. The results are discussed in terms of the role of vagal tone in influencing abnormal cardiac patterns which could result in sudden unexplained death in some epileptic patients.

Amygdala↗

Cloning, expression, and characterization of the lon gene of Erwinia amylovora: evidence for a heat shock response.

The gene encoding the Lon protease of Erwinia amylovora has been cloned by complementation of an Escherichia coli lon mutant. Analysis of the determined nucleotide sequence of the lon gene revealed extensive homology to the nucleotide sequences of cloned lon genes from E. coli, Myxococcus xanthus, and Bacillus brevis. The predicted amino acid sequence of the E. amylovora Lon protease was 94, 59, and 54% identical to the predicted amino acid sequences of the Lon proteases of E. coli, M. xanthus, and B. brevis, respectively. The -10 and -35 promoter regions of the cloned lon gene had extensive homology to the respective consensus sequences of E. coli heat shock promoters. Promoter mapping of the lon gene located the start site 7 bases downstream of the -10 region. Cloning of the lon promoter upstream of a cat reporter gene demonstrated that expression of the E. amylovora lon gene was inducible by a heat shock. This is the first demonstration of a heat shock-regulated gene in E. amylovora. Site-directed mutagenesis of the -10 region of the lon promoter confirmed that the heat shock expression of the E. amylovora lon gene may be mediated by a sigma 32-like factor. Insertional inactivation of the E. amylovora chromosomal lon gene confirmed that the lon gene was not essential for either vegetative growth or infection of apple seedlings. E. amylovora lon mutants had increased sensitivity to UV irradiation and elevated levels of extracellular polysaccharide, suggesting comparable roles for the Lon proteases in both E. amylovora and E. coli.

ATP-Dependent Proteases↗

Functional recovery of noncemented total hip arthroplasty.

Eighteen patients with unilateral hip disease had noncemented total hip arthroplasty. Clinical follow-up data were complete to five years postsurgery. Gait analysis was done preoperatively, at three and six months, and at one and two years. Force plate data showed continued weakness of the operated hip in all patients at two years postsurgery. Preoperative dynamic electromyograms (EMGs) were abnormal in eight patients and showed two patterns. Stance loss seen in three patients was characterized by absence of activity of the gluteus medius and upper and lower gluteus maximus muscles. In five patients, continuous activity occurred in the tensor fascia lata, rectus femoris, and adductor longus muscles during the entire gait cycle. Postoperatively, all abnormal EMGs returned to normal. Four patients with a normal preoperative EMG developed abnormal EMG patterns postoperatively, demonstrating either a prolonged stance or stance loss pattern. All four of these hips have been revised. Although gait characteristics return to normal by two years postsurgery, weakness of the hip persists. This weakness jeopardizes the implant fixation interface. This study supports the prohibition of activities that cause high impact loading of total hip arthroplasties and suggests that a prolonged exercise program be employed postoperatively.

Adult↗

On gene patenting.

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Biotechnology↗