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Biomedical subjects

E J Morgan

Publications and source records attributed to E J Morgan.

At least 37 records · Page 2Linked to original sources
PubMed1978

The obesity-hypoventilation syndrome.

The triad of obesity, hypoventilation and inordinate hypersomnolence characterizes the obesity-hypoventilation syndrome. The reasons for daytime hypoventilation appear related to decreased chemical drives to breathe combined with the added physical impediment of extreme obesity. When the physiology of sleep was investigated in patients with this syndrome, intermittent nocturnal obstructive apneas were documented that produced blood gas abnormalities, arrhythmias and serious elevations of both pulmonary and systemic pressures. The obstructive apneas are due to intermittent loss of muscle tone of the tongue resulting in its prolapse against the posterior pharynx. The special importance of the obesity-hypoventilation syndrome lies in its being an example of a disorder of sleep and breathing that can appear in widely different clinical settings. Therapeutic measures include weight loss, progestational agents or permanent tracheostomy.

Apnea↗
PubMed1976

Abnormalities of lung function in hay fever.

Twenty subjects with symptoms of hay fever were studied to see whether abnormalities could be detected in the function of small airways. The investigations included dynamic compliance at varying respiratory frequencies, closing capacity, residual volume, transfer factor, and maximal expiratory flow-volume curves. The tests were repeated in the winter when symptoms had resolved. Frequency dependence of compliance was found in eight subjects with symptoms (40%), closing capacities being abnormal in only two instances. Conventional pulmonary function tests, including expiratory flow rates at mid vital capacity, were within the predicted range of all subjects. When tests were repeated in the winter, frequency dependence of compliance was no longer present in subjects whose symptoms had resolved. The study suggests that reversible small airway abnormalities are present in a significant proportion of subjects with symptoms of hay fever and that such abnormalities are best detected by the measurement of dynamic compliance at varying respiratory frequencies.

Adolescent↗
PubMed1975

Paradoxical Effect of Actinomycin D: Regulation of Synthesis of Wound RNase at Translation in Turnip Tissue.

Cutting of tissue sections induces RNase (EC 2.7.7.16) activity (phase I) in white turnip (Brassica rapa L. var. rapa) which peaks in 4 or 7 hours and then declines rapidly (phase II). The increase is inhibited by cycloheximide; also RNase from tissue bathed in 99.8% D(2)O during phase I underwent a large increase in buoyant density, indicating that the increased activity is due to de novo synthesis. Actinomycin D inhibited induction of RNase only if given within the initial 45 minutes after cutting. When it was applied after 45 minutes, it caused enhancement (super-induction) of RNase activity for over 24 hours. The half-time for degradation of RNase during phase I in the presence of cycloheximide and phase II in the presence and absence of cycloheximide is the same, indicating that the decline in RNase activity is due to cessation of synthesis. Also the rate of degradation of RNase remains the same during superinduction, thus indicating that actinomycin D superinduction is due to maintenance of synthesis of RNase rather than inhibition of its rate of degradation. Consistent with this is the fact that actinomycin D superinduction of RNase is inhibited by cycloheximide. The evidence is consistent with the hypothesis that messenger RNA for RNase is long-lived and the decline in RNase is due to transscription of a regulator gene coding for a specific repressor protein during phase I which inhibits RNase synthesis at the level of translation. Superinduction of RNase activity by actinomycin D is explicable in terms of (a) inhibition of synthesis of the mRNA coding for a repressor protein that inhibits translation of RNase-specific mRNA, or, (b) differential stability of mRNAs in presence of actinomycin D, and competition among mRNAs for factors rate-limiting to translation, thus favoring synthesis of proteins coded by long-lived messengers.

Journal Article↗