Biomedical subjects
R R Gacek
Publications and source records attributed to R R Gacek.
Fiber orientation of the facial nerve: an experimental study in the cat.
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Radiotherapy for carcinoma of the nasal cavity.
Twenty-five patients with primary epithelial carcinoma of the nasal cavity without nodal or distant metastases were treated by irradiation between 1967 and 1978. Small field, beam-directed techniques delivered 6,000 to 7,000 rads with conventional fractionation. Control of the primary tumor was achieved in 21 (84%) patients after irradiation. All five treatment failures (one infield only, three infield recurrence with lymph node metastases, and one regional cervical node metastasis) were evident within six months; all five patients died of cancer. The adjusted actuarial survival rate at three years was 76%. Failure in the untreated neck was only 5% when the primary carcinoma was controlled and 16% overall. The literature has been reviewed with attention to tumor control rates and survival.
Facial nerve nucleus in the cat. Further study.
The location of efferent neurons, supplying muscles innervated by facial nerve, was studied in the brain stem of the cat using horseradish peroxidase. One to four microliters of HRP was injected in the frontalis, posterior belly of digastric, platysma, and auricularis superior muscles of the kittens. Their representative locations were determined in the facial nucleus. No direct relation between the amount of HRP injected and the numer of labeled neurons was found. The number of positive cells was between 2 and 661. No labeled neurons were found in nucleus of Vth or any other brain stem nuclei.
Petrous apex tumors; diagnosis and management.
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Clinical inferences from recent observations on vestibular neuro-anatomy.
Recent knowledge of the neuro-anatomy of the vestibular system gained as the result of retrograde axonal tracer methods is reviewed. The new findings help explain some clinical features. The findings include separate termination in the vestibular nuclei of the first order neurons from the semicircular canals of the macular; the detailed connections between the eye cerebellar and spinal paths are commented upon.
Location of trochlear vestibuloocular neurons in the cat.
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Location of abducens afferent neurons in the cat.
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Mucocele of the petrous apex.
The first case of a primary mucocele of the petrous apex is presented and the differential diagnosis is briefly discussed. Since this area is unavailable for direct examination, a thorough radiographic evaluation is essential. A mucocele should be suspected when a lytic lesion has a multiloculated appearance and when the contralateral petrous apex is highly pneumatized. Even then, a biopsy may still be needed to make a definitive diagnosis. The appropriate treatment for these cystic lesions is fistulization into a radical mastoid cavity or an exteriorized sphenoid sinus.
Management of temporal bone carcinoma.
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Total obliteration of the chronic draining ear--how I do it.
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Location of commissural neurons in the vestibular nuclei of the cat.
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Properties of central vestibular neurons fired by stimulation of the saccular nerve.
In 4 cats all vestibular afferents in one labyrinth except those innervating the saccular macula were transected and allowed to degenerate. 23--53 days after the initial surgery the central connections of the remaining saccular nerve were studied under chloralose anesthesia. Stimulation of the saccular nerve evoked N1 field potentials in the ipsilateral lateral and descending vestibular nuclei; little or no field potential activity was seen in the superior nucleus. The distribution of field potentials overlapped with that of neurons of origin of the vestibulospinal tracts. Forty-two neurons in the ipsilateral vestibular nuclei, many in the lateral nucleus, responded, often monosynaptically, to stimulation of the saccular nerve with single or double shocks; some of the neurons projected to the spinal cord. All saccular-fired neurons were tested for commissural actions by stimulation of the contralateral vestibular nerve. Many were facilitated, almost none were inhibited. In agreement with earlier work, we conclude that commissural inhibition may be a property of the canal system only.
Transcanal labyrinthectomy.
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Posterior ampullary nerve transection for benign paroxysmal positional vertigo.
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Location of brain stem neurons projecting to the oculomotor nucleus in the cat.
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Localization of abductor and adductor fibers in the kitten recurrent laryngeal nerve: use of a variation of the horseradish peroxidase tracer technique.
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Saccular and utricular input to cat neck motoneurons.
1. In two series of cats all vestibular afferents except those innervating the saccular or utricular macula were transected and allowed to degenerate. Subsequent anatomical and physiological verification showed that the saccular nerve had been selectively spared in six cats. The utricular nerve was wholly or partly spared in five cats, but there was some possibility of contamination from other vestibular afferents. 2. The connections of the remaining nerve with dorsal neck motoneurons were studied 27-179 days after the initial surgery in preparations anesthetized with chloralose. 3. Stimulation of the saccular nerve usually evoked IPSPs in contralateral, EPSPs in ipsilateral neck motoneurons. Some of the potentials were disynaptic, many were later and probably trisynaptic. 4. The effects of utricular nerve stimulation were more complex, perhaps because of contamination by other vestibular, particularly canal, afferents. The predominant pattern consisted of ipsilateral inhibition and contralateral excitation, opposite to the effects of saccular nerve stimulation. Many potentials were disynaptic. 5. Various factors that may complicate interpretation of the results, including plastic changes following denervation, are considered. It is concluded that they are not a significant factor. 6. Our main result is a demonstration that the sacculus can contribute to vestibulospinal reflexes acting on the head.