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Biomedical subjects

D G Hanson

Publications and source records attributed to D G Hanson.

At least 73 records · Page 4Linked to original sources
PubMed1987

Videostroboscopy of the canine larynx: the effects of asymmetric laryngeal tension.

The effects of simulated paralysis of the peripheral laryngeal nerves on patterns of vocal cord vibrations were studied. Videostroboscopy was used in seven anesthetized mongrel dogs to record laryngeal vibrations during direct electrical stimulation of the recurrent and superior laryngeal nerves under conditions of constant airflow. Stroboscopic images obtained from both supraglottic and subglottic aspects were analyzed frame-by-frame. Results indicated that simulated paralysis of the recurrent laryngeal nerve or combined paralysis of the recurrent and superior laryngeal nerves produced a diminished mucosal wave bilaterally, with loss of the two-mass system of vibration and diminished lateral excursion of the normal cord. In contrast, simulated paralysis of the superior laryngeal nerve was characterized by an abnormally exaggerated vertical movement of the paralyzed cord in relation to the normal cord and a horizontal shifting of the glottis from the paralyzed to the normal side during each vibratory cycle. Clinical implications are discussed and the literature reviewed.

Animals↗
PubMed1987

Major complications following tracheoesophageal puncture for voice rehabilitation.

The successful use of the tracheoesophageal voice prosthesis for speech rehabilitation of the total laryngectomy patient has lead to common application of this device. Although the creation of a tracheoesophageal fistula is a simple procedure, it is not without complications. A review of 104 patients who underwent this procedure indicated a complication rate of 25%. Complications were related primarily to the fistula and included migration and progressive enlargement of the puncture, persistent or recurring infection of the fistula site, aspiration pneumonia, and death. Other problems included aspiration of the prosthesis, vertebral osteomyelitis, and tracheal stomal and esophageal stenosis. Many of these patients required hospitalization, intravenous antibiotics, and major surgical procedures to treat these complications. Guidelines for early identification and management of these problems as well as methods to prevent complications are discussed.

Adult↗
PubMed1987

Irradiated mice lose the capacity to 'process' fed antigen for systemic tolerance of delayed-type hypersensitivity.

'Intestinal antigen processing' is a function of the gastro-intestinal tract whereby shortly after an animal has been fed an immunogenic protein antigen, such as ovalbumin (OVA), a tolerogenic form of the protein is generated and can be detected in the circulation. The effect of damage to the intestinal epithelium on the processing of OVA has been examined in lethally irradiated mice. Irradiated animals were fed 25 mg OVA and their serum collected 1 h later. When this serum was transferred intraperitoneally into naive recipient mice, this did not induce the typical suppression of systemic delayed-type hypersensitivity. Results were similar when the serum donors were at 2 days after irradiation, with crypt hypoplasia, and at 5 days after irradiation when there was reactive crypt hyperplasia. However reconstitution of donors with normal spleen cells immediately after irradiation restored their capacity to generate a tolerogenic form of the antigen. Immunoreactive OVA was detected by ELISA in both tolerizing and non-tolerizing sera, and the immunological properties of these sera were not related to serum levels of OVA after feeding. Thus subtle immunochemical alterations in the nature of a protein antigen are likely to be more important than the quantity of absorbed antigen, in influencing systemic cell-mediated immune responses after feeding. The lack of generation of a tolerogenic form of the protein in irradiated mice, unrelated to the pattern of epithelial cell kinetics, and the restoration of this function by normal spleen cells, suggests that lymphoid cells may be involved in the phenomenon of antigen processing.

Animals↗
PubMed1987

Laryngeal modeling: theoretical, in vitro, in vivo.

Because the larynx is situated anatomically in an area which is difficult to measure and visualize, theoretical, in vitro, and in vivo models are used in laryngeal research. Vocal fold vibration was studied in anesthetized dogs, while electrically stimulating independently the superior and recurrent laryngeal nerves under conditions of constant airflow. Photoglottographic (PGG), electroglottographic (EGG), and subglottic pressure signals were obtained while stroboscopically photographing the larynx. Specific points along PGG, EGG, and subglottic pressure waveforms were correlated with laryngeal events which occurred during vibration. The canine larynx, in an experimentally produced phonatory mode, vibrates in a two mass (upper and lower margin) system and appears comparable to modal human voice production. The recorded glottographic waveforms from experimentally produced phonation in the canine are similar to signals recorded from humans. However, observed differences can be related to anatomic differences.

Animals↗
PubMed1986

Increased permeability to polyethylene glycol 4000 in rabbits with experimental colitis.

Little information is available regarding colonic permeability to macromolecules in health or disease states. In vivo permeability of rabbit colon to [14C]polyethylene glycol 4000 (14C-PEG) was examined in the presence of immune complex-mediated experimental colitis and compared with that of partially treated (control) and normal rabbits. Permeability was assessed by urinary 14C-PEG excretion after intrarectal administration of 0.1 mM solution of 14C-PEG (1 ml/kg, 7.5 X 10(6) cpm/ml). Experimental colitis greatly increased colonic permeability (p less than 0.001 in two-way analysis of variance) compared with control and normal groups (2.06% +/- 0.19%, 0.14% +/- 0.04%, and 0.01% +/- 0.004%, respectively, of rectally administered counts). Gel diffusion chromatography showed that absorbed 14C-PEG was excreted into urine unchanged, demonstrating its applicability as an inert, nonmetabolizable macromolecular probe. Urinary clearance after mesenteric vein administration of 14C-PEG was similar in normal animals and animals with colitis, implicating colonic absorption as the source of the group differences. Postmortem histology confirmed the acute colitis lesions in the experimental group. These findings support the hypothesis that nonspecific colonic inflammation is associated with significant alterations of mucosal permeability.

Animals↗
PubMed1986

Transfer of protein antigens into milk after intravenous injection into lactating mice.

We investigated the transfer of bovine serum 125I-albumin (125I-BSA), bovine 125I-gamma-globulin (125I-BGG), 125I-ovalbumin (125I-OVA), and 125I-beta-lactoglobulin (125I-BLG) from the blood into the milk of lactating mice. Equal amounts (by weight) of the radiolabeled proteins were injected intravenously into mice 1 wk postpartum. Total radioactivity, trichloroacetic acid-precipitable radioactivity, and specifically immunoprecipitable radioactivity were measured in serum, mammary gland homogenate, and milk. Clearance of immunoreactive OVA (iOVA) and iBLG from the circulation was more rapid than iBSA and iBGG. The radioactivity in mammary tissue associated with BSA and BGG was greater than 70% immunoprecipitable throughout the 4-h test interval; 125I-OVA and 125I-BLG were less than 12% precipitable 1 and 4 h after injection. In milk obtained at 4 h, there was an approximately 10-fold greater accumulation of iBSA or iBGG than of iOVA or iBLG. These experiments demonstrate that protein antigens differ in their ability to transfer from maternal circulation into milk. The transfer into milk appeared to be in proportion to persistence of the antigens in the maternal circulation.

Animals↗
PubMed1985

Facial nerve evoked potentials.

Evoked potentials representing both intracranial and extracranial activity have been recorded from the canine scalp after retrograde stimulation of peripheral facial nerve branches. A negative electrode at the vertex and a positive electrode at the ipsilateral mastoid (grounded at the contralateral mastoid) show a monophasic negative stylomastoid evoked potential that appears to be generated from the facial nerve trunk at the stylomastoid foramen. When the positive electrode is moved from the mastoid to the posterior scalp (overlying the foramen magnum), a similar potential with a latency 1.5 msec greater is obtained. This brain stem evoked potential is generated from fibers in the vicinity of the root entry zone and the initial trajectory into the brain stem. A potential of similar latency but greater magnitude is recorded with the positive electrode in the cerebrospinal fluid of the posterior fossa.

Animals↗
PubMed1985

Transcutaneous Teflon injection of the paralyzed vocal cord: a new technique.

Because of anatomical deformity, trismus, or for other reasons, it may on occasion be impossible to visualize a larynx by the usual laryngoscopy methods. Such difficulties in patients who have paralytic dysphonia may also make it impossible to effect improved vocal cord closure by the usual techniques of Teflon injection. We have applied a new technique, detailed in this report, to these problem cases. Following topical anesthesia of the nose, nasopharynx, and larynx, 1% Xylocaine is injected over the cricothyroid membrane. A flexible or telescopic laryngoscope connected to a television camera is introduced through the nose or oral cavity, respectively. A 16-gauge spinal needle is introduced into the subglottic tracheal lumen via the cricothyroid membrane and directed into the undersurface of the paralyzed vocal cord under indirect visual control. Teflon is then injected, monitored via the television image. Our early experience with this simple technique indicates that voice improvement is comparable to that expected using conventional transoral laryngoscopic techniques.

Aged↗
PubMed1984

Cinegraphic observations of laryngeal function in Parkinson's disease.

Thirty-two unselected male patients with Parkinson's disease were examined by telescopic cinelaryngoscopy. Correlation of vocal abnormality and general neurologic symptoms with the laryngoscopic examination leads to the conclusion that the phonatory abnormalities noted in Parkinson's disease are related to rigidity in the phonatory posture of the larynx. The described dysfunctions correlated with the symmetry of trunk and limb rigidity in 100% of the patients.

Aged↗
PubMed1983

Manual strangulation injuries of the larynx.

Laryngeal injuries secondary to manual strangulation are seen more often by the forensic pathologist than by the otolaryngologist. Forces sufficient to cause thyroid and cricoid cartilage fractures are usually sufficient to cause acute asphyxia and death. However, due to the static nature of the compressive forces applied in strangulation, fractures of the cartilaginous framework may occur without obvious mucosal disruption or submucosal hematoma formation. If the victim survives the initial assault and the injuries go unrecognized and untreated, delayed life-threatening airway obstruction of long-term vocal dysfunction may result. Computed tomography seems to be an excellent noninvasive technique to evaluate and verify cartilaginous laryngeal fractures and soft-tissue injury. Recognition of the potential for such injuries is the key to management and treatment.

Aged↗
PubMed1983

Technique for long-term feline tracheostomy.

When long-term feline tracheostomy is desired for experimental purposes, a permanent stoma may be established by a modification of the technique described by Miles. Crusting, injury, and obstruction of the stoma are bypassed during healing by an intratracheal tube stent. With the bypass tube in place, the animal breathes humidified air through its nose, and tracheal crusting is minimized. A stout neck dressing prevents scratching and injury to the stoma until it is healed. The technique provides a well-healed, well-tolerated permanent stoma with minimal special animal care.

Animals↗
PubMed1983

Bilateral facial nerve paralysis following arterial embolization for epistaxis.

Risk of carotid artery embolization is usually attributed to inadvertent occlusion of the internal carotid system. This report highlights some recently noted complications associated with occlusion of external carotid branches. A case of bilateral facial paralysis following embolization of the internal maxillary arteries for severe epistaxis is presented. The clinician must recognize that facial paralysis is a real and sometimes inevitable sequela to the ever-increasing practice of arterial embolization in the head and neck.

Arteries↗
PubMed1983

An acoustic analysis of the effects of surgical therapy on voice quality.

An automated computer system was used to measure changes in vocal quality resulting from laryngeal surgery. Five acoustic parameters were computed and seven listeners made judgments on vowel samples recorded before and after surgery from 37 patients. Presurgery and postsurgery changes in the five acoustic measures were compared with the perception of change in vocal harshness. A multiple regression analysis showed that four of the five acoustic measures accounted for a large amount of the variance in the judgment of change of voice quality following surgery. The measures may provide a quick and relatively sensitive method that may be clinically useful in measuring change in vocal quality.

Adult↗
PubMed1982

Pseudomass lesions due to occult trauma of the larynx.

Fracture of the laryngeal skeleton is best diagnosed by computed tomography. Deformity of the laryngeal cartilage may cause signs and symptoms that suggest neoplastic submucosal mass. Symptoms may not develop until years after the original injury. A series is described in which the patients demonstrate the characteristic signs, symptoms, and computed tomographic appearance of old, often forgotten, fractures of the thyroid cartilage. The diagnosis is best made by computed axial tomography of the neck.

Adult↗
PubMed1982

Inhibition of specific immune responses by feeding protein antigens. V. Induction of the tolerant state in the absence of specific suppressor T cells.

The effect of CY pretreatment on the ability of OVA feeding to induce both tolerance and active suppression was examined in mice. CY-pretreated, OVA fed mice were fully unresponsive in both OVA-specific DTH and antibody responses, but, in contrast to untreated OVA-fed mice, did not transfer suppression to normal recipients via splenic lymphocytes. Restoration of Ts activity in CY-pretreated mice was accomplished by reconstitution with normal T cells before antigen feeding, indicating that the CY effect was at the Ts precursor level. In addition, it was found that certain OVA-specific immune parameters (DTH and splenic PFC responses) in recipient mice were susceptible to suppression by transfer of spleen cells from OVA-fed donors, whereas other measures (antigen-induced T cell proliferation and serum antibody titers) were not. The data suggest that CY-sensitive Ts are not necessary for either induction or maintenance of specific tolerance after OVA feeding.

Animals↗
PubMed1979

Binding of ovalbumin to mouse spleen cells with and without carbodiimide.

We studied the binding of ovalbumin (OVA) to mouse spleen cells. In the presence or absence of carbodiimide (ECDI), uptake increased with greater cell numbers, increasing OVA concentration and increasing time up to 60 min. Between 60 and 210 microgram OVA could be coupled with ECDI to 2 X 10(8) cells. In the absence of ECDI, however, OVA uptake was still appreciable, but appeared to be of low avidity as it did not occur in the presence of competing fetal calf serum. These experiments provide a basis for the use of protein coupled to autologous cells in the induction of immunologic tolerance.

Animals↗