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Biomedical subjects

R Amedee

Publications and source records attributed to R Amedee.

At least 19 recordsLinked to original sources
PubMed2001

Primary myxoma of the temporal bone in a 17-year-old boy: case report.

OBJECTIVE AND IMPORTANCE: Only two cases of primary intracranial myxomas have been described previously in the literature: one patient had a primary intracranial myxoma in the pituitary fossa, and the other patient's myxoma was located in the posterior fossa. CLINICAL PRESENTATION: A rare case of primary myxoma of the temporal bone in a 17-year-old boy is described. The patient presented with a history of progressive left-sided hearing loss and increasing headaches of a few months' duration. INTERVENTION: An initial draining procedure in the left ear revealed extant mucous material, and further investigation showed a large calcified lesion involving the petrous and temporal bones and filling the middle fossa. At surgery, a large mucoid-appearing tumor was removed. The tumor pathology revealed a primary myxoma with bone and meningeal involvement. No clinical or histopathological evidence that it was a metastatic lesion was found. CONCLUSION: The features of myxomas on computed tomographic and magnetic resonance imaging, the histopathology, and surgical considerations are discussed.

Adolescent↗
PubMed2001

Juvenile nasopharyngeal angiofibroma.

Juvenile nasopharyngeal angiofibroma is a rare yet potentially destructive vascular tumor that typically affects adolescent males. While the etiology of these tumors remains unknown, great advances have been made in their diagnosis and treatment. When juvenile nasopharyngeal angiofibroma is diagnosed at an early stage, the prognosis is generally very good, as patients can be treated with a combination of pre-operative embolization and surgical resection. Advanced juvenile nasopharyngeal angiofibroma is much more difficult to treat, since orbital and intracranial involvement are common in the natural progression of the disease. However, due to the rather innocuous presenting symptoms (commonly, nasal obstruction and epistaxis), diagnosis most often occurs in the later stages of the disease. For this reason, it is important for all physicians to have a high degree of suspicion for juvenile nasopharyngeal angiofibroma when evaluating a male adolescent with these symptoms.

Adolescent↗
PubMed2000

Possible roles of nitric oxide in the physiology and pathophysiology of the guinea pig cochlea.

Two nitric oxide synthase isoforms (NOS-I and NOS-III) are present in the mammalian cochlea, and many regulatory functions of the inner ear could be mediated by NO. In this study, cochlear potentials and immunohistochemical measures were analyzed by changing the concentration of NO in the guinea pig during intracochlear and intravenous application of an NOS inhibitor and an NO donor. In anesthetized guinea pigs the NOS inhibitor NG-nitro-L-arginine-methylester (L-NAME) was applied by intracochlear perfusion or intravenously. The cochlear potentials and blood pressure were measured during and after the application. Cochleae were removed and prepared for morphological and immunohistochemical examinations by light and electron microscopy. The same series of experiments was performed with the NO donor S-nitroso-N-acetyl-penicillamine (SNAP). Cochlear potentials were not altered during intracochlear perfusion or intravenous application of L-NAME or SNAP. With intravenous application of the substances, significant alterations in the systemic blood pressure were seen. No morphological alterations were noted but in the immunohistochemical investigations significant changes were detected by electron microscopy. Several possible functions of NO in the inner and outer hair cells, stria vascularis and ganglion cells are discussed. Our results suggest that NO has a major effect on the physiology of the inner and outer hair cells.

Animals↗
PubMed2000

Intracanalicular meningioma.

Intracanalicular meningiomas are extremely rare and difficult to differentiate from intracanalicular vestibular schwannomas. We report an unusual case of a posterior fossa meningioma in the proximal internal auditory canal that was originally diagnosed as a vestibular schwannoma due to its appearance on magnetic resonance imaging. However, closer inspection of the preoperative neuroimages revealed features inconsistent with vestibular schwannoma that suggested the possibility of other less common lesions.

Cranial Fossa, Posterior↗
PubMed1999

Giant fibrovascular polyp of the esophagus.

Giant fibrovascular polyps (FVP) are the most common intraluminal tumors of the esophagus. The case of a second, nonrecurrent FVP is presented. A thorough review of the literature was conducted to provide an informative discussion on this benign but potentially life-threatening neoplasm.

Esophageal Neoplasms↗
PubMed1997

Characterization of nitric oxide synthase isoforms expressed in different structures of the guinea pig cochlea.

Nitric oxide synthase (NOS) activity and NADPH diaphorase staining has previously been reported in mammalian cochlea. Here we demonstrate immunoreactivity for neuronal-type NOS I and endothelial-type NOS III in the cochlea of the guinea pig. NOS I immunoreactivity was seen in inner and outer hair cells, and spiral ganglion cells. Staining for NOS I was also shown in basal and intermediate cells of the stria vascularis, spiral ligament cells, and the media of vessels near the modiolus. An antibody to NOS III stained primarily vascular endothelial cells. Some NOS III immunoreactivity was also detected in spiral ganglion cells. An antibody to the inducible-type NOS II did not stain any structure of the guinea pig cochlea, suggesting that this isoform is not expressed under physiological conditions. Nitric oxide produced by NOS I and/or NOS III may act as a neuromodulator in the organ of Corti and could also play a role as a regulator of cochlear blood flow.

Animals↗
PubMed1997

Allergic diagnosis: skin testing and rast.

In a minority of patients with allergic rhinitis, diagnosis of the offending allergens is necessary for control of symptoms. Skin endpoint titration (SET) testing, the most advanced form of skin testing, and the radioallergosorbent test (RAST) are the only two diagnostic tests that give quantitative results upon which to base immunotherapy. Patients who undergo diagnostic testing must understand the commitment involved in a program of immunotherapy. This review hopes to enable clinicians to better understand the techniques of skin testing and RAST and how and when these tests may be of use to their patients suffering from allergic rhinitis.

Humans↗
PubMed1997

Tympanic membrane displacement analysis after glycerol intake: effects on intracranial and intracochlear fluid pressure.

BACKGROUND: Intracranial pressure is transmitted to the perilymph of the cochlea via the cochlear aqueduct and to the endolymph via Reissner's membrane. The tympanic membrane displacement analyzer (TDA) is a new system that may provide a useful, noninvasive, indirect method to identify intracranial and intracochlear pressure changes. METHODS: We performed measurements in 20 persons with normal hearing and in 29 patients with various unilateral diseases of the inner ear such as sudden hearing loss or Meniere's disease. Another series of measurements were done in 15 normal-hearing persons and in 15 patients with Meniere's disease before and after oral ingestion of glycerol. RESULTS: In the first series of measurements, no significant differences in the tympanic membrane displacement were found between normal-hearing individuals and patients with unilateral diseases of the inner ear. In the second series, in all individuals a temporary, relative decrease in intracochlear pressure was found after oral ingestion of glycerol but without any significant difference between the two groups. CONCLUSIONS: These results revealed that the TDA is apparently not useful in the evaluation of patients having Meniere's disease.

Acoustic Impedance Tests↗
PubMed1997

Nicotine addiction and smoking cessation.

Cigarette smoking remains the greatest threat to public health in our society and is responsible for one of every five deaths in the United States. While the prevalence of smoking has declined dramatically over the past 30 years, over 26% of Americans continue to smoke. In Louisiana, one third of adult men and one quarter of adult women smoke. The irony of this problem is that smoking is a modifiable behavior. To better counsel their patients regarding smoking cessation, health care practitioners should be aware of the health risks of smoking, the benefits of smoking cessation, and therapies available to assist their patients in breaking the habit. This article reviews the current literature and addresses these issues.

Adult↗
PubMed1994

Menière's disease.

Menière's disease is the most common cause of true vertigo and it affects about 2.4 million Americans. Episodic tinnitus, hearing loss, vertigo, and aural fullness are the classic findings. The symptom which is most debilitating and which causes most people to seek treatment is vertigo. Most patients respond extremely well to medical management and only rarely is surgery necessary. This paper discusses the symptoms, diagnosis, and clinical course of Menière's disease. Medical and surgical therapeutic options are discussed.

Administration, Oral↗
PubMed1991

Functional deficits of cranial nerves in patients with jugular foramen lesions.

Lower cranial neuropathies are a leading presenting symptom in patients with tumors involving the jugular foramen. The purpose of this study is to assess acute and chronic functional deficits along with neurologic findings in 31 patients who underwent resection of a tumor involving the jugular foramen. Preoperative nerve dysfunction made intraoperative preservation unlikely, while postoperative lower cranial nerve dysfunction was found to be transient in many patients. Compensation of permanent dysfunction was usually excellent.

Journal Article↗
PubMed1989

Juvenile angiofibromas: a 40-year surgical experience.

A series of 22 patients with histologically confirmed angiofibroma were treated primarily by surgical removal at the University of Freiburg ENT clinic during the 40-year period, 1946-1986. These tumors were staged according to size and extension on the basis of roentgenographic and surgical findings. Specific analysis of the operative approaches and recurrence rate by stage are included. Recurrent or residual disease was handled by surgical excision, irradiation, embolization, or a combination of these methods. The complication and morbidity rates were extremely low, while the mortality rate was zero. The tumor specimens received from the last 5 patients were evaluated for the presence of sex hormone receptors. No specific estrogen, progesterone or androgen receptors were detected in these tissues.

Adolescent↗
PubMed1988

The motor innervation of the soft palate. An anatomical study in guinea pigs and monkeys.

In an effort to gain a more precise understanding of the motor innervation of the soft palate, a neuroanatomical tracer (horseradish peroxidase) was injected into the vela of nine guinea pigs and four monkeys. After 48 h the animals were sacrificed and frozen frontal sections were appropriately reacted with tetramethylbenzidine and counterstained with neutral red, and then evaluated by means of light microscopy. In all specimens retrogradely labeled neurons appeared in the brain stem. The distribution patterns of these labeled cells were to a large degree comparable in both the guinea pigs and the monkeys. The complex motor innervation of the soft palate was found to involve at least five different centers, with the strongest staining seen in the nucleus ambiguus and the motor nucleus of the trigeminal nerve. Additional cells of origin were discernible in the retrofacial nucleus. Facial neurons, however, were labeled only occasionally. Findings also showed that a previously undescribed component from the hypoglossal nerve appears to be essential for lateral soft palate movement in both animal models.

Animals↗
PubMed1988

Diseases of the intrapetrous carotid artery.

In the early years of skull base surgery, total tumor removal was often deemed impossible due to involvement of the intrapetrous carotid artery. In contrast, previously considered unresectable lesions may be removed totally in selected cases, with reasonable expectation of successful treatment at the present time. Current techniques and operative exposures, when modified to accommodate the problem of intracranial extensions of tumor and when approached with neurosurgical collaboration, permit the removal of many of these difficult tumors. This retrospective study of 33 patients treated over the past 5 years offers a critical analysis of our treatment, and a categorization of abnormalities known to affect this anatomic region containing the vessel.

Adenocarcinoma↗
PubMedDate not supplied

[Fluorine-18]fluorodeoxyglucose positron emission tomography, DNA ploidy and growth fraction in squamous-cell carcinomas of the head and neck.

BACKGROUND: Positron emission tomography (PET) offers an opportunity to examine noninvasively cellular functions with different tracers. [(18)F]Fluorodeoxyglucose (FDG) is most commonly used in identifying malignant tumors. Several tumor biologic characteristics (tumor cell viability, growth faction, treatment response to radiation, cell membrane dysfunction, recurrence rate) are suggested to be characterized by [(18)F]FDG PET. The aim of this study was to assess which other tumor biologic characteristics of squamous-cell carcinoma of the head and neck are correlated with [(18)F]FDG PET. METHODS: [(18)F]FDG PET was performed in 14 patients with squamous-cell carcinomas of the upper digestive tract (TNM classification T(2)-T(4), N(1)-N(3)). After attenuation correction, predefined areas of the tumor were semiquantitatively analyzed by the technique of the region of interest and calculated as standard uptake values (SUV). Afterwards, 5 biopsies of different tumor regions were obtained during endoscopy in each patient under general anesthesia, and a correlation between SUV of [(18)F]FDG PET and tumor biologic parameters was attempted. These parameters included: quantitative DNA measurements (i.e. 2c deviation index, 5c exceeding rate), immunohistochemical assessment of growth fraction (i.e. Ki67-MIB-1, PCNA) along with morphological tumor front grading. RESULTS: The results revealed a marked variation of proliferation and cellular differentiation in various regions of the tumor for all parameters examined. There was a close correlation between [(18)F]FDG uptake and growth fraction (r = 0.83 for Ki67-MIB-1 and r = 0.8 for PCNA). A poor correlation was found between DNA aneuploidy (r = 0.4) or tumor front grading (r = 0.12) and [(18)F]FDG uptake. CONCLUSIONS: Our results confirm previous clinical and histologic observations that squamous-cell carcinomas of the upper digestive tract are heterogeneous tumors. Ki67 antigen, which has been shown to be of predictive value for proliferation and individual prognosis, correlated with [(18)F]FDG uptake. Using [(18)F]FDG PET, the main proliferation centers of inhomogeneous squamous-cell carcinomas could be identified with possible clinical implications for patient management.

Adult↗
PubMedDate not supplied

Histological grading, growth fraction and DNA-ploidy as criteria for the treatment of pharyngeal and supraglottic squamous cell carcinomas: a preliminary, prospective study.

BACKGROUND: Individualized treatment for patients with squamous cell carcinomas is most desirable. Biologic parameters of tumors may provide relevant criteria to achieve this goal. The aim of this study was: (1) to avoid elective neck dissection in patients with squamous cell carcinomas of the pharynx and supraglottis staged N0 by ultrasonography; (2) to administer postoperative radiotherapy only in patients staged 'highly aggressive' by biologic tumor parameters, in order to reduce patient morbidity and to improve quality of life. STUDY DESIGN AND METHODS: This prospective trial was performed in 35 patients (any T stage, N0 or N1 by ultrasonographic examination). Tumor biopsies were taken for histological examination and for evaluation of some biological tumor markers. These parameters comprised DNA cytometric examinations, histological grading of the tumor front and immunohistochemical staining for proliferation markers (MIB1, PCNA). Based on these parameters, tumors were classified into 'low aggressive' (group 1) and highly aggressive (group 2) behavior. In all patients, second primaries were excluded by endoscopy, and the presenting tumor was resected with clear margins. In cases of ultrasonographically enlarged lymph nodes, functional neck dissection was performed. When biologic tumor profile showed low aggressive behavior (group 1), no postoperative radiotherapy was advised. In cases of highly aggressive tumors, radiotherapy was recommended postoperatively independent of all other parameters (group 2a and 2b). RESULTS: The average follow-up was 36 months (range 16-65 months). Fifteen patients were included in group 1, 20 patients in group 2. Three patients with highly aggressive tumors who refused RTx were regarded independently (group 2b). In this pilot study of 35 patients, there was no difference in disease-free survival between group 1 and group 2a. Twenty-five of 35 patients were alive with no evidence of disease 29-65 months after treatment (3 died of disease; 5 died of second primary carcinomas; 2 died independent of disease). Eleven of 15 patients survived disease free in group 1, 13/17 in group 2a. In group 2b, 2 out of 3 patients, who were advised but refused postoperative radiotherapy, had recurrences. CONCLUSIONS: The results of this preliminary study point towards usefulness of some tumor biologic parameters in decision making for individualized treatment in patients with squamous cell carcinomas.

Adult↗