Biomedical subjects
J J Holt
Publications and source records attributed to J J Holt.
In vitro isolation of Neospora caninum from a stillborn calf in the UK.
Neospora caninum was isolated in Vero cell culture from the brain of a stillborn calf. This isolate (designated NC-LivB1) is the first to be obtained from cattle in the United Kingdom and was confirmed as N. caninum by immunofluorescence with specific antibodies and by internal transcribed spacer 1 (ITS1) sequence analysis. Differences were found between NC-LivB1, other bovine isolates and canine isolates of N. caninum and closely related protozoal parasites, using random amplified polymorphic DNA polymerase chain reaction (RAPD - PCR) techniques.
Isolation of bovine Neospora in Britain.
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Nasal septum after sublabial transseptal transsphenoidal pituitary surgery.
Transseptal transsphenoidal approach to the pituitary fossa is a well-described and effective procedure. This article relates our experience with this procedure with specific emphasis on the nasal septum, both before and after surgery. It has been our experience that this surgery has minimal local complications in the nose and it would appear to improve septal alignment with subjective improvement in nasal function as reported by the patient. A total of 55 patients undergoing a sublabial transseptal transsphenoidal approach to the pituitary fossa were included in this study. All other approaches to the pituitary gland were excluded. Visual changes and headaches were the most common presenting symptoms, occurring alone or in combination in 28 (51%) patients. Twelve (22%) patients reported symptoms of nasal obstruction before surgery and only one (2%) after surgery. A moderately or severely deviated septum was noted in 30 (54%) patients before surgery and 4 (7%) patients after surgery. The septum was straight in 21 (38%) patients before the procedure and 49 (89%) patients after the surgery. Sinusitis developed in two patients, and one patient subsequently required surgery. No synechiae or septal perforations were noted.
The stylomastoid area: anatomic-histologic study and surgical approach.
This three-part study explored the difficult problem of dissecting the facial nerve through the soft tissues of the mastoid tip. The anatomic relationships of the mastoid tip tissues were measured in 20 specimens. At the stylomastoid foramen, the facial nerve lies an average of 9 mm from the digastric muscle, 11 mm from the external canal, and 21 mm from the nerve's parotid bifurcation. The histologic relationships between the nerve sheath and the mastoid tip fascial tissues were examined in 10 specimens. The tight adherence of sheath and fascial fibers prevent their easy separation. By applying this new anatomic and histologic knowledge on cadaver specimens, the author refined a technique for the safe dissection of the facial nerve through mastoid tip tissues. This technique has proven successful in the operating room.
Noise exposure in the rural setting.
Noise levels of 155 tractors on 36 farms were studied. The range of noise levels at the driver's ear level with radios off and windows closed (if so equipped) was from 78 to 103 dB. Seventy-five percent of tractors without cabs had noise levels in excess of 90 dB, compared to only 18% of tractors with cabs. The use of a radio adds an average of 3.1 dB of noise. When some cab windows are open and the radio is on, an average of 4.2 dB is added to the cab noise. From the results of this study, the authors recommend hearing protection when time on a tractor with a cab approaches 3 to 4 hours and when time on a tractor without a cab approaches 1.5 to 2 hours. Limited use of the radio is also recommended.
Ear canal cholesteatoma.
Although cholesteatomas are more commonly found in the middle ear and the mastoid, the disease can occur in the external ear canal. All cases of ear canal cholesteatoma treated by the author were reviewed. There were nine ears in seven patients, who had an average age of 62 years. The lesions ranged in size from a few millimeters to extensive mastoid destruction. Smaller lesions can be managed by frequent cleaning as an office procedure. Larger lesions require surgery, either canaloplasty or mastoidectomy. The otolaryngologist should suspect this disease in the elderly. Microscopic examination of the ear with meticulous cleaning of all wax, especially in elderly patients, is most useful in detecting early disease. Frequent applications of mineral oil to the canal should be used in the management of the disease and to prevent recurrence.
Protection of sigmoid sinus during neurotologic surgery.
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Diseases of the external ear canal.
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Otalgia: the many causes.
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A new method of collecting nasal secretions.
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Neck dissection and combined therapy. Study of effectiveness.
Data on 1,385 neck dissections in 1,192 patients were studied to evaluate the effectiveness of treatment with operation alone and with various forms of combined therapy in controlling cervical metastasis. Of the 1,192 patients, 837 were treated by operation (neck dissection) alone, and the remainder had preoperative or postoperative radiation to the primary site and to the entire side of the neck that was dissected. In no stage of neck disease was either form of combined therapy superior to operation alone in decreasing the rates of recurrence. In an attempt to simulate a randomized, prospective study in a clinical situation for which the end results were already known, we used a separate statistical analysis--a case-control technique to specifically address the issue of the effectiveness of postoperative radiation in decreasing the frequency of recurrences after dissection in the various stages of disease. No evidence of a relationship between recurrence and the administration of planned postoperative radiation was found.
Neck dissection: is it worthwhile?
Data on 1,048 neck dissections in 881 patients were studied to evaluate the effectiveness of treatment in controlling cervical metastasis. Of the 881 patients, 74.5% were treated by surgery alone, and most of the remainder had either planned preoperative or postoperative radiation to the primary site and the entire neck. Planned preoperative or postoperative radiation was defined as the delivery of 4,000 rads or more to the entire neck 123 days before (preoperative) or after (postoperative) neck dissection. In these groups, most patients received more than 5,000 rads. Ninety-six patients received preoperative radiation that did not satisfy these criteria and were grouped separately. The group with neck dissection alone had recurrence rates in the dissected side at 2 years of 7.5, 20.2, and 37.4%, respectively, for No, N1, and N2 staged necks. There were no differences in recurrence rates for the groups with radiated necks in the stage II (N2) necks compared with each other or with the group having surgery alone. Most recurrences, when they occurred in the neck, were manifest by 2 years. Mean follow-up in the entire study was 3.5 years. Two patients were lost to follow-up and were presumed to have died from cancer. When compared with pathologic staging, clinical staging was imprecise in one-third of the cases.
High frequency limitations on Mach bands.
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Phase perception in the high spatial frequency range.
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Effects of large-bore middle ear ventilation tubes.
Patients with chronic otitis media that did not respond to conventional treatment were studied for the types and incidence of complications from the use of large-bore tubes inserted into their ears. The most common complication was otorrhea (41%, 50 of 123 ears). Permanent perforation occurred in 25% (17/68 ears). Use of large-bore tubes proved effective and continues to be indicated in certain conditions of chronic otitis media that are refractory to other forms of treatment.