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Biomedical subjects

A J Gulya

Publications and source records attributed to A J Gulya.

At least 19 recordsLinked to original sources
PubMed1999

The NIDCD's clinical trials cooperative groups: a brief overview.

The National Institute on Deafness and Other Communication Disorders (NIDCD) embarked on the establishment of two clinical trials cooperative groups in October 1996 in response to a scientific research need. It intended that the clinical trials cooperative groups (CTCGs) design and implement clinical trial protocols capable of addressing the efficacy of therapeutic interventions for diseases and disorders of human communication. Most commonly, owing to the substantial number of patients required, the trials are expected to involve multiple study sites, with each study site adhering to a uniform study protocol, standardized treatment regimens, and prescribed data collection procedures. A complex administrative structure is required to coordinate the activities of the CTCGs and to assure compliance with a myriad of government regulations. Similarly, participating study sites must meet stringent requirements including leadership by an individual experienced in clinical trials. There is a relative dearth of experienced clinical trialists dedicated to research in human communication. This article details the complexities involved in the conduct of multicenter clinical trials and the NIDCD's efforts to promote clinical trials activities and to develop clinical trials training opportunities.

Clinical Trials as Topic↗
PubMed1998

Growth of human paragangliomas in the subrenal capsule of the nude mouse.

Paragangliomas are generally benign, highly vascular, and slowly growing tumors of neural crest lineage that occur disproportionately in women. Surgery can manage small tumors expeditiously, but extirpation of large tumors is associated with morbidity and even mortality. Radiation therapy offers relatively good tumor control but also presents development of a secondary malignant neoplasm as a possible consequence. Cancer chemotherapeutic agents have been used only in rare metastasizing paragangliomas because they also are associated with considerable morbidity. A better understanding of the biology of human paragangliomas, to encompass the molecular biology of these tumors, is essential for the development of a less morbid, tumor-targeted therapy. This preliminary investigation is aimed at testing the hypothesis that the subrenal capsule of the nude mouse is a viable model for in vivo study of the molecular biology of human paragangliomas. None of the five tumors implanted survived for the duration of the study period. Accordingly, the nude mouse subrenal capsule does not appear to be useful in the study of human paragangliomas.

Animals↗
PubMed1996

The scala vestibuli for cochlear implantation. An anatomic study.

BACKGROUND: Traditionally, cochlear implantation has used the scala tympani (ST) for electrode insertion. When faced with ST ossification, the surgeon may elect to drill out the cochlea to accomplish partial electrode insertion. Theoretically, another option in this situation is to insert the electrode into the scala vestibuli (SV). OBJECTIVE: To determine whether or not the dimensions of the SV are sufficient to accommodate an electrode array so as to assess the feasibility of SV cochlear implantation. METHODS: The study of 20 normal human temporal bones, comparing the maximum diameter and surface area of the ST with those of the combined SV and scala media. RESULTS: The dimensions of the SV and scala media were comparable to those of the ST and appeared sufficient to accommodate a cochlear implant electrode array. CONCLUSION: It appears that the combination of SV and scala media is a viable alternative route for electrode insertion, at least on the basis of anatomic dimensions, in those cases in which the ST is obliterated.

Cochlea↗
PubMed1996

Hearing aids. I. Conventional hearing devices.

State-of-the-art hearing aids incorporate advances in signal processing, miniaturization, and programmability. This technological progress has been accompanied by parallel enhancements in evaluating and fitting strategies. In addition, in the past several years, knowledge has increased about the influences of amplification on hearing ability and about the influences of hearing ability on benefit from amplification.

Hearing Aids↗
PubMed1995

Flow-sensitive magnetic resonance imaging in the evaluation of cerebrospinal fluid leaks.

Cerebrospinal fluid (CSF) leaks involving the skull base are associated with considerable morbidity and mortality, and often present a diagnostic challenge. Current diagnostic methods are invasive and cumbersome and involve substantial radiation exposure of the patient. The authors identified seven patients with clinically suspected CSF leaks and evaluated them with a flow-sensitive magnetic resonance imaging (MRI) sequence in addition to more conventional studies. In cases with active CSF leakage, flow characteristics were documented with slow-flow and diffusion-weighted MRI. Unlike current approaches, MRI offers the advantages of rapidity, non-invasiveness, and absence of ionizing radiation. Preliminary results suggest that flow-sensitive MRI may have a role in the evaluation of CSF leaks involving the skull base and temporal bone.

Adult↗
PubMed1994

Environmental tobacco smoke and otitis media.

Environmental tobacco smoke (secondhand smoke) is a health hazard experienced by one half to two thirds of the nation's children younger than 5 years of age. Although the role of environmental tobacco smoke in the genesis of pulmonary disease in children has been increasingly recognized, somewhat less attention has been paid to the role of environmental tobacco smoke in the development of childhood otitis. This presentation will review current data regarding environmental tobacco smoke, with a particular emphasis on its effects on the ears and eustachian tube. Current American Academy of Otolaryngology-Head and Neck Surgery Foundation, Inc. education efforts will also be discussed.

Acute Disease↗
PubMed1994

Computer-assisted assessment of cochlear nerve fibers.

Quantitative assessment of cochlear nerve fibers, with statistical analysis of histologic specimens, is facilitated by the application of computer image processing techniques. Three algorithms, developed for the evaluation of cochlear sections, are presented, MANUAL, AIDED, and AUTO, in order of increasing degree of automation and decreasing requirement for operator intervention. All three algorithms demonstrate high accuracy and consistency in identifying cochlear nerve fibers and quickly provide statistics regarding the target nerve fiber population. These algorithms have potential utility in the study of cochlear nerve pathologic alterations, as for example, with intracochlear electrical stimulation.

Animals↗
PubMed1993

The glomus tumor and its biology.

This section has attempted to detail the histopathologic, biologic, pathophysiologic, and epidemiologic characteristics of jugulotympanic paragangliomas. These features do not stand devoid of clinical significance, but rather lay the foundation for the formulation of logical diagnostic and therapeutic approaches to these fascinating tumors.

Ear Neoplasms↗
PubMed1993

Facial nerve neuroma.

Facial nerve neuromas are an unusual cause of facial nerve dysfunction and hearing loss. As clinical manifestations do not accurately reflect tumor extent, imaging techniques can greatly assist the clinician in appropriate diagnostic evaluation and management.

Adult↗
PubMed1993

Neurologic paraneoplastic syndromes with neurotologic manifestations.

Evidence supports the hypothesis that autoimmune mechanisms are operational in the etiopathogenesis of certain neurologic paraneoplastic syndromes (PNSs), including paraneoplastic encephalomyelitis (PEM) and paraneoplastic cerebellar degeneration (PCD). The antibodies (Anti-Hu and Anti-Yo), the antigens (Hu and Yo), and complementary DNA clones encoding Hu and Yo, central to PEM and PCD, respectively, have been isolated. In contrast, the antigens, and antibodies if any, involved in autoimmune cochleovestibular dysfunction remain unknown. The temporal bone histopathology and neuropathology of 2 patients, 1 with PEM and 1 with PCD, who developed signs and symptoms of cochleovestibular dysfunction, are reviewed and contrasted to the literature. It is concluded that both auditory and vestibular symptomatology and pathologic alterations can be seen in association with neurologic PNSs and that studies using the antigens and antibodies involved in neurologic PNSs may provide a new perspective on the investigation of autoimmune cochleovestibular dysfunction.

Aged↗
PubMed1992

Labyrinthine enhancement on gadolinium-enhanced magnetic resonance imaging in sudden deafness and vertigo: correlation with audiologic and electronystagmographic studies.

Sudden deafness with or without vertigo presents a difficult diagnostic problem. This article describes 12 patients with enhancement of the cochlea and/or vestibule on gadolinium-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (MRI), correlating the enhancement with the auditory and vestibular function. All patients were studied with T2-weighted axial images taken through the whole brain, enhanced 3-mm axial T1-weighted images taken through the temporal bone, and enhanced T1-weighted sagittal images taken through the whole brain. Cochlear enhancement on the side of hearing loss was found in all the patients. The vestibular enhancement correlated with both subjective vestibular symptoms and objective measures of vestibular function on electronystagmography. In 2 patients, the resolution of symptoms 4 to 6 months later correlated with resolution of the enhancement on MRI. No labyrinthine enhancement was seen in a series of 30 control patients studied with the same MRI protocol. Labyrinthine enhancement in patients with auditory and vestibular symptoms is a new finding and is indicative of labyrinthine disease. While abnormalities on electronystagmograms and audiograms are nonspecific and only indicate a sensorineural problem, enhanced MRI may separate patients with retrocochlear lesions, such as acoustic neuromas, from those in whom the abnormal process is in the labyrinth or the brain.

Adult↗