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Biomedical subjects

D G Hanson

Publications and source records attributed to D G Hanson.

103 records · Page 6Linked to original sources
PubMedDate not supplied

Evoked responses from peripheral stimulation of the facial nerve.

Evoked responses to electrical stimulation of the facial nerve were recorded in dogs with vertex electrodes placed both inside and outside the skull. Three waveforms were recorded. The first two waveforms appeared to be related to electrical activity carried by antidromic propagation within fibers of the facial nerve. The third waveform appeared to be caused by the muscular response that occurred as a result of orthograde conduction in the nerve. The effects of changing the stimulation site, voltage, duration, and frequency were recorded. It appears that, by means of far-field techniques, it is possible to reliably record evoked responses that reflect antigrade conduction via fibers of the facial nerve.

Animals↗
PubMedDate not supplied

Laryngeal configuration associated with glottography.

This report describes a method for testing and confirming the relationship of glottography to the vibratory movements of the vocal folds. According to this method, vocal fold movement is monitored by photoglottography (PGG) and electroglottography (EGG) as photographs are taken using a 80-microsecond flash provided by a laryngostroboscope. The flash is recorded as an impulse on the PGG waveform, indicating the location on the glottographic signals of the corresponding single frame photograph. We then present a test case, in which various vocal fold configurations are documented, demonstrating that the timing of glottal events can be correlated to glottographic signals by this method.

Adult↗
PubMedDate not supplied

Plasma immunoreactive-trypsin(ogen) levels during development.

We previously showed that the uptake of intact trypsin from the intestine of suckling animals was greater than that of weaned animals. To extend these studies, we measured plasma cationic immunoreactive-trypsin(ogen) in human subjects aged 3 days to 43 years. In agreement with the observation of other investigators, we found that the concentration of cationic immunoreactive-trypsin(ogen) was significantly increased in 3-day-old infants compared with other age groups. None of the cationic immunoreactive-trypsin in adult samples was bound to alpha 1-antitrypsin, whereas 28% of cationic immunoreactive-trypsin in infant samples was bound to alpha 1-anti-trypsin.

Adolescent↗
PubMedDate not supplied

Genetic sensorineural deafness in adults.

Progressive genetic sensorineural hearing loss is a common problem in adults which is frequently incorrectly diagnosed or escapes diagnosis as to etiology altogether. If the hearing problem becomes manifest in the twilight of the patient's life it is often identified with the nondescriptive term "presbycusis." In all patients with sensorineural hearing loss, extrinsic (environmental) causes should be ruled out after which intrinsic or genetic etiology should strongly be considered, recognizing that extrinsic factors can be superimposed. A group of young adults was studied and diagnosed as having genetic progressive hearing loss. Polytomography ruled out the theoretical possibility of chochlear otosclerosis. The diagnosis of this disorder tests most heavily on the history and audiometric configuration which is characteristically flat or basin shaped with fairly good discrimination. Of further diagnostic significance was the fact that some patients, early in the course of their difficulty, presented with a predominantly low- or high-frequency loss which, over time, assumed a flat audiometric shape. The most important pathological finding from human temporal bone studies was atrophy of the stria vascularis.

Adult↗
PubMedDate not supplied

Improving grant applications for research in communicative disorders.

In making research funding appropriations, Congress considers, in part, the percentage of applications which are approved, but cannot be funded with the existing budget. The Communicative Disorders Program will have difficulty justifying increased Congressional appropriation without an increase in the number of approved grant applications. Investigators in otolaryngology and other fields of communicative disorders are urged to submit innovative proposals of high scientific quality to be considered for funding. The National Institutes of Health (NIH) review process is explained and suggestions for improving a potential grantee's application are made.

Communication↗
PubMedDate not supplied

Vocal fold paresis in Shy-Drager syndrome.

Twelve patients with Shy-Drager syndrome (SDS) presenting symptoms of multiple nervous system atrophy and orthostatic hypotension were examined for laryngeal movement disorders and vocal impairment in speech. Vocal fold abductor paresis was found in 11 patients and was bilateral in 10. Speech task performance was recorded in SDS patients, Parkinson patients and age- and sex-matched controls. Trained listeners with inter-rated reliability greater than or equal to .85 judged each recording on 20 attributes while blind to speaker identity. SDS patients had a breathy and strained voice quality, reduced loudness, monopitch and monoloudness, imprecise consonants, variations in rate and rate-slowing, suggesting a flaccid type of dysarthria. In comparison with Parkinson patients, SDS patients had excess vocal hoarseness, intermittent glottal fry and a slow and deliberate speaking rate. Orthostatic hypotension, laryngeal stridor, hoarseness, intermittent glottal fry and slow speech rate were found to be discriminating symptoms of SDS.

Aged↗
PubMedDate not supplied

Glottographic measurement of vocal dysfunction. A preliminary report.

Objective measurement of vocal function is important in evaluating phonatory disorders, planning treatment, and documenting the effects of therapy. Glottographic measurement, ie, measures that describe glottal movement, can be performed and analyzed relatively easily, and can be related to the pathophysiology of vocal dysfunction. In our clinic, simultaneous recording of acoustic, photoglottographic and electroglottographic signals is being used in the evaluation of patients with voice disorders associated with neurologic impairments. Our experience with these measures indicates that they may provide detailed information about the vibratory patterns of the vocal folds, which appears to differentiate some phonatory characteristics among patients with differing types of disorders.

Aged↗
PubMedDate not supplied

Photographic studies of the larynx in central laryngeal paresis and paralysis.

Characteristic patterns of laryngeal dysfunction due to central neurologic disease are documented by 16 mm ciné photography. Representative patients are used to describe typical patterns of abnormal laryngeal function which occur in upper motor neuron, extrapyramidal, cerebellar, nuclear and mixed foci of lesions. The pitfall of brief indirect laryngoscopy without visual documentation is emphasized as a factor in misdiagnosis of patients with laryngeal disease of central origin. The value of more careful evaluation of similar patients is emphasized in relation to better understanding of laryngeal function and improved patient care.

Adolescent↗
PubMedDate not supplied

Inhibition of orally-induced immune tolerance in mice by prefeeding an endopeptidase inhibitor.

Intragastric feeding of T-dependent protein antigens to mice induces substantial systemic tolerance in specific antibody and cell-mediated immune responses. To evaluate the role of gastrointestinal digestion in this phenomenon, the trypsin inhibitor aprotinin was fed to adult BDF1 mice prior to tolerogenic feedings of ovalbumin or human gamma globulin. As assessed by measurement of protein-specific antibody responses, aprotinin significantly reduced tolerance induced by feeding carrier protein, but not tolerance induced by parenteral antigen injection. Aprotinin also reduced oral tolerance to ovalbumin as measured by delayed-type hypersensitivity and T cell proliferative responses. However, aprotinin did not alter antibody tolerance to a carrier-associated hapten in the same animals. Feeding of human gamma globulin concomitantly with aprotinin induced specific antibody responses without further immunization, and reduced subsequent tolerance. Aprotinin also increased the level of immunologically detectable ovalbumin found in the serum following antigen feeding. The data support the hypothesis that aprotinin indirectly mediated changes in specific stimuli available to the lymphoid system as a result of alterations in gastrointestinal processing of fed antigens rather than to direct effects of aprotinin upon systemic immune responses.

Administration, Oral↗
PubMedDate not supplied

Endopeptidase inhibition and intestinal antigen processing in mice.

The role of gastrointestinal digestive processes in the systemic availability of ingested protein antigens was examined by feeding the trypsin inhibitor aprotinin intragastrically to mice and measuring uptake of ovalbumin and 14C-polyethylene glycol (MW 4000) from the gastrointestinal tract. Trypsin and chymotrypsin activities in the intestinal lumen were significantly reduced by aprotinin feeding. Aprotinin slowed stomach emptying, but radioimmunoassays for immunoreactive ovalbumin in the serum of mice prefed aprotinin showed 12-fold elevations within 1 hr after ovalbumin feeding. Uptake of a nonmetabolized macromolecular probe, 14C-polyethylene glycol-4000, increased less than two-fold when fed with aprotinin under the same conditions, indicating that the increased uptake of immunoreactive ovalbumin was not due to changes in intestinal permeability. The results show that inhibition of luminal proteolysis caused significant increases in the serum concentration of immunoreactive ovalbumin, indicating that acute inhibition of luminal proteases permits larger quantities of relatively intact protein to interact with mucosal absorptive surfaces. These results support the hypothesis that pancreatic proteases modulate antigen absorption from the lumen in adult animals.

Animals↗