Biomedical subjects
Publications and source records attributed to L Jacobs.
A case of ectopic lacrimal gland within the orbit causing progressive exophthalmos and visual loss is presented. The orbital mass, identified by computerized axial transverse tomography, had characteristics which were different from other orbital tumors identified to date by this technique.
Analysis of 25 patients who fulfilled clinical and radiographic criteria for the diagnosis of "normal pressure" hydrocephalus (NPH) demonstrated (1) a significant relationship between presence of motor signs with good outcome and absence of motor signs with poor outcome following ventricular shunting, (2) symptoms and signs of parkinsonism in 40% of patients in whom the diagnosis of NPH was made, and (3) no reliable relationship between radiographic measurements or cisternogram appearance and outcome following shunting. The clinical picture is the most important factor in selection of NPH patients for surgery.
The effects of eyelid closure on oculomotor function was examined in 11 patients with palatal myoclonus. In eight patients, eyelid closure induced gross rhythmic vertical or almost oscillatory movements of the globes, which were synchronous with the rhythmic beat of the palatal myoclonus. The rhythmic vertical ocular movements induced by eyelid closure replaced calorically induced or spontaneous horizontal nystagmus present when the lids were open. Vertical ocular motions persisted during some stages of slow-wave sleep and reappeared during each stage of rapid eye movement. The physiologic basis of the palato-ocular synchrony may be similar to the eyelid closure, vertical eye movements, and palatal myoclonus that occurs in monkeys on stimulation of the central tegmental fasciculus.
Inhalation of histamine diphosphate aerosol (1.6 per cent, 10 breaths) produced a 218 +/- 54.6 per cent (mean +/- SE) increase in airway resistance in 16 normal subjects with colds compared with a 30.5 +/- 5.5 per cent increase in 11 healthy control subjects (P less than 0.01). There was no significant difference in mean baseline airway resistance between the two groups. Inhalation of saline produced no significant change in airway resistance in either group. Isoproterenol hydrochloride (0.5 per cent, 1 breath) or atropine sulfate aerosol (0.2 per cent, 20 breaths) each reversed and prevented the increase in airway resistance by histamine, indicating that the bronchoconstriction was caused by smooth muscle contraction and that post-ganglionic, cholinergic pathways were involved in the mechanism. In 6 subjects with colds, citric acid aerosol (10 per cent, 5 breaths) caused bronchoconstriction that lasted up to 30 sec after inhalation, a significantly greater effect than that observed in control subjects or in the same subjects after recovery (P less than 0.05). Prior inhalation of atropine aerosol (0.2 per cent, 20 breaths) prevented the bronchoconstriction after citric acid aerosol in all 6 subjects. The threshold concentration of citric acid that produced cough in 7 subjects with colds was significantly lower than that in control subjects or in the 7 subjects after recovery (P less than 0.05), suggesting that the exaggerated cholinergic response was due to a decreased threshold for stimulation of the rapidly adapting sensory receptors in the airways. We have provided evidence that respiratory viral infections that produce airway epithelial damage temporarily cause these subjects to develop more bronchoconstriction after inhaling smaller doses of histamine than do healthy subjects. The fact that atropine prevents this response and that the threshold to cough is temporarily decreased is compatible with our hypothesis that airway epithelial damage by infection exposes and, thus, "sensitizes" the rapidly adapting airway receptors to inhaled irritants, causing increased bronchoconstriction via a vagal reflex. Damage to the airway epithelium may occur as a result of mechanical factors, inhaled chemicals, and pollutants, such as ozone, infections, or perhaps as a result of the action of materials released endogenously (e.g., from mast cells, white blood cells, or platelets). "Sensitization" of rapidly adapting sensory receptors in the airways may be an important factor in asthma and in other diseases of airways.
One hundred eleven patients with supratentorial cerebrovascular disease were studied by computerized axial tomography (CT scanning). With one exception, every patient who had a normal scan 48 hours after the onset of symptoms was ultimately diagnosed as having had transient ischemic attack, although in nearly one-third, the clinical diagnoses at the time of the scan was infarction. A normal CT scan, therefore, augurs a good outcome of supratentorial cerebrovascular disease. Ninety-eight percent of the patients with infarction had abnormal scans, with areas of decreased density in a vascular distribution. Pitfalls in the diagnosis of infarction were (1) initially normal CT scans that changed to abnormal after 48 hours, and (2) mass effect of infarction leading to misdiagnosis of brain tumor. Serial studies eliminated both pitfalls. Intracerebral hemorrhages had a distinctive high density appearance. In 43 percent of patients whose scans showed hemorrhage, the clinical diagnosis was thrombosis. Many did not have symptoms, signs, or outcome of cerebral hemorrhage, and the diagnosis would not have been suspect were it not for the CT scan.
One hundred thirty-five normal volunteers were examined by computerized tomography (CT) and their ventricular size was measured by planimetry. A pattern of change in ventricular size from the first through the ninth decades was discerned and quantified. A gradually progressive increase in ventricular size from the first through sixth decades was followed by a dramatic increase in the eighth and ninth. The range of normal ventricular size was relatively more wide in the eighth and ninth decades than in the first seven; thus, abnormalities of ventricular size may be more easily identified in younger than older subjects. These data are more valuable than those from pneumoencephalography or autopsy studies because CT is not subject to the artifact inherent in those procedures.
Seventy-nine autopsy correlations of CT scans showed (1) excellent correlations in normal brains, but the size of the lateral ventricles consistently larger during life than after death; (2) a distinctive pattern differentiating obstructive from nonobstructive hydrocephalus; (3) infarctions appearing as areas of decreased densities of parenchyma in vascular distributions; (4) distinctive high density appearances of hemorrhages that differentiated them from infarctions and, in general, all other pathologic processes; (5) supratentorial, intraventricular, and posterior fossa tumors appearing as masses that displaced, distorted, collapsed, and enlarged normal spaces and structures such as ventricles and pineal gland; (6) 11 false-negative CT scans in some cases of brain stem infarction, brain stem hemorrhage, and small metastasis; and (7) an overall accuracy of 86.2 percent of CT scanning in correctly identifying pathology of the brain.
Twenty patients with normal pressure hydrocephalus were examined by computerized axial transverse tomographic (CT) scanning and the results were compared with pneumoencephalographic findings and clinical responses to ventricular shunting. The CT scan revealed significant cortical atrophy, not demonstrated by pneumoencephalogram in seven patients. The cortical atrophy was confirmed by autopsy in one case. This examination also revealed greatly enlarged ventricles (25 to 40 per cent of intracranial volume) in eight patients up to 4 years after ventricular shunting. There was no relationship between the presence or absence of cortical atrophy, or the postoperative ventricular size, and the clinical responses to ventricular shunting. Current concepts of normal pressure hydrocephalus must be revised in view of these findings.
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