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Biomedical subjects

G R Holt

Publications and source records attributed to G R Holt.

At least 109 records · Page 6Linked to original sources
PubMed1977

Parotid fistula and tympanic neurectomy.

Parotid fistula is most commonly a posttraumatic situation. In posttraumatic cases, spontaneous closure of the fistula is the general rule. Conservative approaches to the occurrence of a parotid fistula are eliminating oral intake by the patient and applying a pressure dressing while maintaining nutrition by the intravenous route. Anticholinergic drugs decrease the production of saliva and thus would appear to be beneficial. When a parotid fistula does not heal under these conditions, then more aggressive treatment is indicated. Treatment should be based on whether the fistula is ductal or glandular in origin. Several methods of treatment have been advocated in the past. Low dose radiotherapy has been mentioned by some authorities as the treatment of choice for parotid fistula. This was used in one of our patients without response. Excision of the fistulous tract with ligation of the parotid duct has been advocated by some authorities. Tympanic neurectomy appears to be a satisfactory method of dealing with selected parotid duct fistulas, and glandular fistulas are best treated by tympanic neurectomy. Suppression of parasympathetic activity by the use of tympanic neurectomy has been said on some occasions to be transient (for example, Frey's syndrome). In dealing with parotid fistulas it would not appear to matter whether the effects are transient or permanent. The suppression of activity by tympanic neurectomy lasts long enough to allow for healing of the fistulous tract and relief of symptoms.

Adult↗
PubMed1977

Recurrent laryngeal nerve injury following thyroid operations.

Preoperative and postoperative laryngoscopy should be performed with thyroid operations. A prospective study of 121 thyroid operations from June 1970 to December 1974 was analyzed. There was a 4.2 per cent recurrent laryngeal nerve injury incidence in 217 nerves at risk, four of nine injuries being permanent. Of 217 superior laryngeal nerves at risk, 1.4% were injured, one of three permanently. Previous thyroid operations may place the laryngeal nerves at a greater risk. Transient edema of the laryngeal nerve in 13.4% of the patients was believed due to endotracheal intubation. There seemed to be no difference in the incidence of injury whether the nerves were seen or palpated. It is recommended that indirect laryngoscopy be performed in the course of evaluating thyroid disorders.

Humans↗
PubMed1976

Vertigo.

Vertigo, with or without nystagmus, may accompany many diseases. Most causes are transient and benign. A systematic approach saves valuable time. Nonrotational dizziness must be distinguished from true vertigo in which a sensation of motion is involved. Careful evaluation of nystagmus is essential, as is a complete cardiovascular examination. Meniere's syndrome, while common, is overdiagnosed.

Brain Diseases↗
PubMedDate not supplied

The fate of fresh, layered, nonsutured and sutured, autogenous cartilage in the rabbit model.

OBJECTIVE: To compare the thickness, area, and volume of sutured and nonsutured multilayered cartilage grafts in a rabbit population. DESIGN: Autogenous rabbit cartilage grafts were harvested, layered, and placed in the contralateral auricle. Half the grafts were sutured; the other half were nonsutured. Graft thickness, area, and volume were measured before implantation, after 90 days in vivo, and after explantation. RESULTS: The area and volume of the cartilage grafts increased during the 90-day period. Histologically, this was caused by increased fibrous tissue around the cartilage grafts. Minimal cartilage resorption was observed. No differences were noted between sutured and nonsutured grafts. CONCLUSIONS: Autogenous, fresh, uncrushed, layered nonsutured or sutured cartilage grafts are well tolerated. Statistically significant increases in the area and volume of autogenous, fresh, uncrushed, layered cartilage grafts occurred primarily because of fibrous tissue formation at the margins of the layered grafts. Suturing had no effect on the postoperative volume retention of these layered grafts. This information will be helpful to the facial plastic surgeon when using fresh-layered autogenous cartilage grafts during cosmetic or reconstructive procedures. Arch Facial Plast Surg. 2000;2:256-259

Animals↗
PubMedDate not supplied

Assessment of tympanometry abnormalities of the tympanic membrane.

Isolated abnormalities of the tympanic membrane have been postulated to affect tympanometry. The authors tested 33 abnormal tympanic membranes in 19 patients with tympanosclerosis and/or thin membranes (having no middle or fibrous layer) against a control group of 32 normal ears in 16 age- and sex-matched patients. All selected patients were free of middle ear disease on the basis of normal hearing, normal pneumatic otoscopic findings, and the presence of crossed acoustic reflexes or normal findings at paracentesis. All patients in the control group had normal type A tympanograms, while 20 (61 per cent) of the tympanic membranes in the experimental group produced abnormal tympanograms. Of the 20 abnormal tympanic membranes, 35 per cent were type As, 35 per cent were type Ad, 5 per cent were type B, and 25 per cent were type C. The tympanosclerotic membranes were more likely to have increased stiffness on the tympanogram, such as As, or B, while the thin membranes had an Ad configuration. The greater the extent of the abnormality within the tympanic membrane, the more abnormal was the tympanogram. This study has demonstrated that isolated abnormalities of the tympanic membrane, such a tympanosclerosis and thin membranes, can alter the tympanogram in the absence of middle ear disease, and that the type of tympanogram can be predicted from the nature and extent of the abnormality. Therefore, an abnormal tympanogram may indicate middle ear disease, abnormality of the tympanic membrane, or both. The presence of an acoustic reflex is important in this differentiation.

Acoustic Impedance Tests↗
PubMedDate not supplied

Treatment of chronic otitis media with effusion: results of tympanostomy tubes.

Insertion of tympanostomy tubes to provide prolonged aeration and drainage of the tympanum in cases of chronic secretory otitis media has become the most commonly performed operation in children. To investigate the therapeutic efficacy of current treatments of chronic secretory otitis media, the authors undertook a randomized clinical trial with four treatment arms: myringotomy alone, tympanostomy tubes, adenoidectomy and myringotomy, and the combination of adenoidectomy and tympanostomy tubes. This report describes the preliminary (one-year) outcome in the group of children who were treated with tympanostomy tubes. The observed average differences between the myringotomy and tympanostomy tube groups were small, with the exception of one variable (time to first recurrence). Although the clinical importance of these differences remains to be established, the authors believe they are substantial enough to justify continued use of tympanostomy tubes in the primary surgical therapy of chronic secretory otitis media, when medical therapy and observation indicate the need for drainage to improve hearing or correct anatomic deformities of the tympanum.

Audiometry, Pure-Tone↗
PubMedDate not supplied

Electrical interactions via the extracellular potential near cell bodies.

Ephaptic interactions between a neuron and axons or dendrites passing by its cell body can be, in principle, more significant than ephaptic interactions among axons in a fiber tract. Extracellular action potentials outside axons are small in amplitude and spatially spread out, while they are larger in amplitude and much more spatially confined near cell bodies. We estimated the extracellular potentials associated with an action potential in a cortical pyramidal cell using standard one-dimensional cable theory and volume conductor theory. Their spatial and temporal pattern reveal much about the location and timing of currents in the cell, especially in combination with a known morphology, and simple experiments could resolve questions about spike initiation. From the extracellular potential we compute the ephaptically induced polarization in a nearby passive cable. The magnitude of this induced voltage can be several mV, does not spread electrotonically, and depends only weakly on the passive properties of the cable. We discuss their possible functional relevance.

Action Potentials↗
PubMedDate not supplied

Late recurrence of a frontal sinus cholesteatoma.

The longest recorded recurrence of a frontal sinus cholesteatoma with involvement of the orbit, frontal bone, and floor of the anterior cranial fossa is presented. Radical surgery is required and often craniotomy is necessary. Bony reconstruction of defects should not be undertaken until recurrence has not been present for at least a year. A review of the literature and a discussion of the origin of cholesteatomas is given.

Adult↗
PubMedDate not supplied

Predictive value of tympanometry in middle ear effusion.

The presence of middle ear effusion may be inferred from a tympanogram by the configuration of the pressure compliance curve. Not infrequently, however, effusion is absent at the time of surgery when strongly indicated by preoperative tympanometry. We evaluated this discrepancy by contrasting preoperative tympanograms with the findings at surgery in 462 children, aged 4 to 8 years, with clinical evidence of persistent effusion in 909 ears. Based on these results we can classify tympanograms as to high risk for effusion, intermediate, and low risk. The proportion of ears with effusion was 83%, 47%, and 34%, respectively. The proportion of ears with fluid in the high risk tympanogram group did not change appreciably over a 1- to 8-week period, ie, no trend toward spontaneous resolution occurred. The high incidence of effusion at surgery in our low risk group is far higher than expected and is presumably due to reinfection of these ears during the time between examination and operation.

Acoustic Impedance Tests↗
PubMedDate not supplied

Estrogen receptor in the larynx of the aged baboon (Papio cynocephalus).

Using autoradiographic techniques, tritiated estrogen-receptor complex intranuclear labeling was identified in certain laryngeal tissues of four aged female baboons; no complex labeling was found in the control animal. Three significant findings were felt to be derived from this study. One, surface epithelium of the larynx had essentially no estrogen-receptor activity. Two, all tissues of mesenchymal origin, especially lamina propria, muscle, dense connective tissue, and fat had consistently high levels of nuclear localization of the labeled estrogen. The binding affinity seemed to be the highest at the anterior commissure and the immediate anterior subglottic space. Three, there was a high level of receptor binding in laryngeal cartilage and perichondrium. Since the activated hormone-receptor complex modulates gene expression to alter the amount of mRNA, sex steroids have a direct regulatory effect upon the target cell and, perhaps through an induction process, can exert an indirect effect upon adjacent tissues. It is postulated that since the larynx is a sexually dimorphic organ, the sex steroids and their receptors may play a role in altered phonation during aging and possibly in the development of laryngeal neoplasms and other diseases. Therefore, hormonal manipulation may play a future role in the therapy of laryngeal diseases. This study represents the first demonstration of estrogen receptors by specific anatomic location in the primate larynx with significant localization in the mesenchymal tissues but not in the epithelial tissues.

Adipose Tissue↗
PubMedDate not supplied

Dacryocystorhinostomy utilizing an anterior lacrimal sac flap to periosteum technique.

Dacryocystorhinostomy is used in the effective treatment of epiphora secondary to obstruction of the lacrimal drainage system. Common causes of obstruction include canalicular disruption, lacrimal sac fibrosis, and external and internal nasal trauma. Most techniques of dacryocystorhinostomy attempt to suture the lacrimal sac mucosa to the nasal mucosa. At best this is technically difficult, and the mucosa frequently tears. A technique is presented using an anteriorly based lacrimal sac pedicle flap sutured to the periosteum of the anterior lacrimal crest. The sutured flap is quite strong, and the procedure is technically simpler than others. A brief description of the causes of lacrimal obstruction is given. The Jones primary and secondary dye tests for lacrimal system patency are reviewed.

Humans↗
PubMedDate not supplied

Unilateral tonsillar enlargement.

Unilateral tonsillar enlargement may result from infection, chronic inflammatory response, or neoplasm. Neoplasms that commonly produce a unilaterally enlarged tonsil include lymphomas (lymphocytic and histiocytic types) and squamous cell carcinomas. Rarer tumors include extramedullary plasmacytomas, Hodgkin's disease, leukemia, and metastatic neoplasms. Sixteen cases of unilateral tonsillar enlargement owing to causes other than squamous cell carcinoma are reviewed. When examining a patient with unilateral tonsillar enlargement, diagnosis of a neoplastic disease must be considered.

Adolescent↗
PubMedDate not supplied

The effect of tonsillectomy on impedance audiometry.

In an experimental group of 22 patients undergoing elective tonsillectomies and having normal preoperative middle ear function, there is a significant development of abnormal tympanogram types, loss of crossed acoustic reflexes, and decrease in middle ear compliance on the first postoperative day when compared to a control group. Postoperative recovery of middle ear function begins at one week and is usually completed by one month. The loss of acoustic reflexes occurs in those patients with extreme changes in compliance and abnormal tympanogram types. The authors postulate that these changes in middle ear function in the immediate posttonsillectomy period might be due to the surgical disturbance of the peritubal lymphatic drainage, causing engorgement of the tympanic and tubular mucosa; and to abnormal swallowing with impaired coordination of the nasopharyngeal and tubal musculature. These data are helpful in investigating the tonsillar effect on middle ear function and disease.

Acoustic Impedance Tests↗
PubMedDate not supplied

Acute coalescent mastoiditis.

A retrospective review of 11 cases of acute coalescent mastoiditis from 1974 to 1979 is presented. The common historical data include the recent onset of purulent otitis media, which was often incompletely treated with antibiotics, and fever, lethargy, and irritability. The eardrums were red, bulging, and usually intact. A postauricular abscess was present, and the affected ear protruded downward and outward. The mastoid radiographs invariably showed cloudiness and dissolution of the air cell septations. Initial therapy included paracentesis for culture and sensitivity, and initiation of parenteral antibiotics. Surgical therapy consisted of wide myringotomy, drainage of the postauricular abscess, and complete mastoidectomy. Hearing was normal postoperatively in all cases.

Acute Disease↗