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Biomedical subjects

J C Johnson

Publications and source records attributed to J C Johnson.

At least 163 records · Page 9Linked to original sources
PubMed1979

Aberrant jugular bulb presenting as a middle ear mass.

Case reports of 3 patients seen with a bluish mass behind the tympanic membrane are presented. The initial diagnosis was probable glomus tumor. In 1 patient, middle ear exploration confirmed the presence of a high-lying jugular bulb. In the other 2, venography demonstrated that the jugular bulb projected superiorly into the middle ear cavity. In all 3, polytomography demonstrated a dehiscence of the bony septum which normally separates the jugular bulb from the hypotympanum. When a bony dehiscence is seen in the absence of destructive changes, a diagnosis of aberrant jugular bulb is strongly suggested.

Adult↗
PubMed1978

Normal pressure hydrocephalus, parkinsonism, and primary empty sella--coincidence or cause-effect?

The triad of normal-pressure hydrocephalus, parkinsonism, and primary empty sella appeared in a 70-year-old woman. There was dramatic resolution of the extrapyramidal signs and symptoms on treatment with levodopa-carbidopa and ventriculojugular shunt. The syndrome may be the result of several mechanisms, but an alteration of cerebrospinal fluid (CSF) pressure dynamics may be the sole etiology for this triad.

Aged↗
PubMed1978

Comparison of analysis techniques for electromyographic data.

Electromyography has been effectively employed to estimate the stress encountered by muscles in performing a variety of functions in the static environment. Such analysis provides the basis for modification of a man-machine system in order to optimize the performances of individual tasks by reducing muscle stress. Myriad analysis methods have been proposed and employed to convert raw electromyographic data into numerical indices of stress and, more specifically, muscle work. However, the type of analysis technique applied to the data can significantly affect the outcome of the experiment. In this study, four methods of analysis are employed to simultaneously process electromyographic data from the flexor muscles of the forearm. The methods of analysis include: 1) integrated EMG (three separate time constants), 2) root mean square voltage, 3) peak height discrimination (three level), and 4) turns counting (two methods). Mechanical stress input as applied to the arm of the subjects includes static load and vibration. The results of the study indicate the comparative sensitivity of each of the techniques to changes in EMG resulting from changes in static and dynamic load on the muscle.

Electromyography↗
PubMed1977

Esophageal intramural pseudodiverticulosis.

Three cases of esophageal intramural pseudodiverticulosis (EIP) are described and the literature reviewed. We conclude that EIP is an inflammatory disease of unknown etiology characterized by dilatation of the esophageal submucosal glandular elements. The classic radiographic picture which is that of collar-button-shaped outpouchings projecting in a perpendicular fashion from the luminal surface is mainly related to dilatation in the glandular ductal system. It is usually diagnosed in the sixth and seventh decades, but all ages may be affected. Dysphagia is a very common but not universal symptom of the disease process. Approximately one third of these patients have diabetes mellitus. Strictures of the esophagus are frequently seen, and varying degrees of esophagitis may be manifest endoscopically. Esophageal motility disturbances are common and may be severe. Candida infestation with and without tissue invasion has been seen in a number of patients and should be searched for in all cases of EIP.

Candida albicans↗
PubMed1976

New evidence for inferoposterior myocardial infarction on surface potential maps.

Extensive body surface potential recording was performed in 22 patients 2 to 4 weeks after an acute inferoposterior myocardial infarction. Serial isometric projection maps were viewed millisecond by millisecond throughout ventricular excitation, and a second series of maps were examined after removal of the expected range of normal potential distribution. Three major findings outside the normal range appeared: (1) In 6 patients, an early zone of abnormal positivity developed in the left anterior chest at xiphoid level between 15 and 30 msec after onset of the QRS complex; (2) in 13 other patients, a large zone of positivity developed high on the left anterior chest (subclavicular region) between 30 and 60 msec after QRS onset; and (3) in 8 patients the long-lasting rim of negativity about the lower chest was strictly abnormal compared with the expected range. Thus, in 19 of 22 patients the potential map expression was outside the normal range, whereas only eight standard electrocardiograms revealed persistent Q waves with a duration greater than 30 msec. We believe the mid and late activation changes are related to ischemically induced alterations in the temporal sequence of ventricular excitation, not easily appreciated by conventional means of recording but obvious with the departure map technique.

Action Potentials↗
PubMed1976

Visual loss and perioptic vascular malformations in the eye and orbit.

Three patients with monocular visual symptoms had intraocular vascular malformations, presumably congenital, in the affected eye. Special radiographic techniques (magnification of the orbit with subtraction of overlying bone during carotid arteriography) were necessary to demonstrate the orbital perioptic vascular malformations that were responsible for the visual symptoms.

Adult↗
PubMed1976

Peroneal spastic flatfoot syndrome.

Tarsal coalitions are not the sole cause of peroneal spastic flatfoot, and any irritative lesion in the peritalar area can induce protective contraction of any or all of the muscles bridging the peritalar joints. True muscular peroneal spasm has been shown to be present on a clinical basis in this entity where tarsal coalitions are not present. Neoplasm should be included in the differential diagnosis of the rigid flatfoot deformity.

Adolescent↗