Biomedical subjects
G R Holt
Publications and source records attributed to G R Holt.
Bipolaris-caused fungal sinusitis.
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Toxicology of upper aerodigestive tract pollutants.
The field of environmental toxicology has become quite important to the study of environmental health in human beings. The stability of the ecosystem in which we live is threatened by the nearly 5 million chemical compounds that have been synthesized worldwide, many of which have real or potentially toxic effects on the environment and on life forms. Four major groups of chemicals--metallic elements, nonmetallic elements, organic compounds and inorganic compounds--have certain agents within them that are known toxins to human beings. Some of these agents have an as yet unknown effect, whereas others have been well characterized. They can be found in the workplace, home, and outdoors, and many are unseen and odorless. In the past, most agents have been described in terms of their carcinogenic potential or major toxic effects on organ systems. It is now likely that the important characterization of some of these agents referrable to the upper aerodigestive tract should be at their receptor sites and identify the very discrete and small effects on these sites and their cumulative effects. The concept of threshold is probably an arbitrary one because to date these discrete effects have not been studied. Susceptibility on an individual basis probably varies from low to high, depending on the patient's immunologic and defense mechanisms and the existence of congenital or acquired risk factors. New attention must be given to more subtle effects on the upper aerodigestive tract (i.e., sinusitis and laryngitis) in view of the potential effects of certain toxic agents on these tissues.
An intraosseous device for studies of bone-healing. The effect of transforming growth-factor beta.
A novel implantable device, the analytic bone implant, was used in order to establish a model for studies of bone-healing and the evaluation of factors that augment the process, such as transforming growth-factor beta (TGF-beta). This device was implanted into the tibiae of four baboons. After healing, bone was removed from the center chamber. Recombinant human TGF beta-1 was then delivered to the core of the device. After twenty-two days of healing, the device was disassembled and the newly formed bone was removed from the core of the implant for histomorphometric analysis. An analysis of the bone revealed a substantial effect of TGF-beta on osteoblastic activity and proliferation compared with that seen in control and placebo groups. However, despite increased osteoblastic activity, trabecular bone volumes at twenty-two days were equivalent among the groups. The number of osteoclasts and the erosion of the surface were also increased, although not significantly so. Substantial endochondral formation of bone was seen in the supraperiosteal tissues directly over the implants that contained TGF-beta but not over the implants in the control and placebo groups. These data demonstrate the utility of this bone-implant model for studies of bone-healing with minimally invasive methods. In addition, use of the device provided the first in vivo data on the effects of TGF-beta at an intermediate (twenty-two-day) time-point in the healing process in a non-human primate.
The new role of the specialist in primary care military medicine.
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What's new in otorhinolaryngology.
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Dermoids and teratomas of the head and neck.
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Massive airway hemorrhage after transtracheal aspiration.
An instance of massive hemorrhage following transtracheal aspiration with successful resuscitation is reported. Indications for the procedure are pneumonia with poor ability to produce sputum, fever, or pulmonary infiltrate in a stuporous patient, and facial injuries which would complicate nasotracheal suction. The cricothyroid membrane is recommended as the site of entry. If airway hemorrhage does occur, immediate maintenance of the airway and tamponade of the bleeding can aid in successful resuscitation of the patient.
E.N.T. manifestations of Von Recklinghausen's disease.
Von Recklinghausen's Disease (VRD) is a neurocutaneous, systemic disease characterized by CNS tumors and disorders, cafe-au-lait spots, generalized cutaneous neurofibromata, skeletal deformities, and somatic and endocrine abnormalities. It is an autosomal dominant, hereditary disorder found in approximately 1:2500 to 3300 births. There are many manifestations of this disease in the head and neck region of interest to the otolaryngologist. Case reports of three patients with multiple ENT involvements are detailed. A review of the literature is presented with a brief discussion of diagnosis and treatment. The most common intracranial tumor in the adult is the acoustic neuroma, usually bilateral, while in the child it is the astrocytoma. A defect in the sphenoid bone is common and may produce temporal lobe herniation into the orbit causing pulsatile exophthalmos. Involvement of the facial bones usually causes radiolucent defects secondary to neurofibromata within nerve pathways, and a variety of asymmetrical changes, especially within the mandible. "Elephantiasis" of the face is a hypertrophy of the soft tissues overlying a neurofibroma, often quite extensive and disfiguring. Laryngeal and neck involvement may compromise the airway and early and repeated surgical intervention is required. The over-all malignancy rate approaches 30%, indicating that the patient with VRD may be predisposed to developing a malignancy. There appears to be an increased surgical risk in these patients, with some demonstrating abnormal responses to neuromuscular blockade.
Immediate open reduction of nasal septal injuries.
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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.
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.
Lacerations of the lacrimal apparatus, parotid duct, and facial nerve: case report.
Diagnosis and surgical treatment of a male patient with severe facial lacerations involving the lacrimal duct, parotid duct, and buccal branch of facial nerve are presented. Careful wound care and localization of severed nerves and ducts, and repair under microscope are emphasized.
Mass in the neck--a diagnostic challenge.
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Pathologic quiz case 1. Malignant melanoma of the nasopharynx.
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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.
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.
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.