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Biomedical subjects

M Lang

Publications and source records attributed to M Lang.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

Nicotine-induced airway smooth muscle contraction: neural mechanisms involving the airway epithelium. Functional and histologic studies in vitro.

To assess the mechanism of and the role of the epithelium in nicotine-induced bronchoconstriction in vitro, we performed a combined functional and histologic study. Functional study: We suspended tracheal strips or rings from 16 ferrets (1124 +/- 561 g, mean +/- SD) in organ baths. Alternate tracheal strips had their epithelium removed. Dose-response curves to acetylcholine (ACh) and nicotine were established for pairs of tissues with and without epithelium, each pair receiving only one dose of nicotine. Nicotine induced brief muscle contractions not exceeding 25% of the ACh-induced maximum. Contractions were blocked by hexamethonium and 10(-7) M atropine and were abolished or inhibited strongly by tetrodotoxin (TTX), suggesting the involvement of nicotinic neuronal and muscarinic smooth muscle receptors. Removal of the epithelium strongly inhibited contractions at concentrations of nicotine greater than 3 x 10(-5) M which completely removed any dose-response effect. ACh-induced contractions were unchanged, demonstrating smooth muscle integrity. We suggest that the removal of the epithelium attenuates nicotine-induced bronchoconstriction through the removal of nerves running in or close to the epithelium. Histologic study: In tracheae from 15 ferrets (8 male, 7 female), mean weight (+/- SD) 1288 (+/- 470) g, we examined 4 techniques of epithelium removal: (1) gentle scraping with a scalpel blade moved backwards (away from the cutting edge), (2) moving a Q-tip through the unopened tracheal tube without lateral pressure, and (3, 4) stroking the mucosa of opened tracheal segments with a Q-tip, exerting (3) light or (4) moderate pressure. All methods were equally (97%-100%) efficient in removing the epithelium but differed in the amount of damage caused to the basement membrane and/or submucosal tissue. Method (2) caused less damage to the basement membrane than the other methods but still removed almost one-third of it. The study showed that complete removal of the epithelium is at the expense of the submucosa and that a given result of "epithelium removal" is also attributable to removal of the neighboring subepithelial structures.

Acetylcholine↗
PubMedDate not supplied

Anesthesia in a patient with acute respiratory insufficiency due to relapsing polychondritis.

We report on a male patient with advanced relapsing polychondritis (RP), who was hospitalized for an ophthalmologic intervention. He had to undergo a tracheostomy with general anesthesia due to respiratory decompensation. RP is a rare systemic, inflammatory, and destructive disease of the cartilaginous structures leading to multiple functional disorders in the affected organs. Involvement of the tracheobronchial tract may cause severe respiratory problems and even life-threatening respiratory insufficiency. Treatment consists of corticoids, chemotherapy, antirheumatics, and surgical intervention. Anesthesiologic management requires careful preoperative evaluation of vital organ functions, in particular respiration, so that the anesthetic approach can be tailored to the individual needs of each patient.

Acute Disease↗
PubMedDate not supplied

[Diagnostic and prognostic value of the EEG in the immediate aftermath of cranial trauma].

The authors studied the EGGs of 262 cases of post-traumatic coma and drew the following conclusions: 1. If the EEG shows sleep activity immediately after cranial trauma, the prognosis is generally good. 2. The existence of electrical reactivity to sensory stimulation is a favourable sign and examination of the symmetry of reactions often demonstrates a focal lesion which is not otherwise apparent. However, the absence of localizing signs in the EEG does not necessarily preclude the existence of an intracranial focal lesion; nor do signs of focalization necessarily confirm the existence of a lesion. 3. In equivocal cases, the echo-EG and arteriography should be contemplated. 4. Focal irritative abnormalities in an elderly patient suggest a very poor prognosis. 5. A recording which implies mtabolic disorder should prompt the immediate search for the causal disturbance. If correction of the metabolic disturbance is not followed by rapid improvement of the EEG, the prognosis is very unfavourable. 6. A focal lesion associated with the coma will affect the prognosis but surgical correction of the lesional effects may also get rid of the disturbances of consciousness.

Adolescent↗