PubMed Health⌕ Search

Biomedical subjects

R Ramírez-Camacho

Publications and source records attributed to R Ramírez-Camacho.

At least 19 recordsLinked to original sources
PubMed2006

Central role of supporting cells in cochlear homeostasis and pathology.

HYPOTHESIS: Supporting cells have a crucial role in degenerative and regenerative events of primary sensorial hair cells of the organ of Corti. This new role should determine future studies about pathophysiology of hearing loss and its regenerative treatment. SUPPORTING EVIDENCE: Recent findings suggest an active role of supporting cells in the maintenance of hair cell function and structure. Evidences of high energy consumption and close proximity to auditory nervous fibers suggesting K+ active exchange, preferential expression of specific proteins and antigens, presence of glucocorticoids receptors, affinity for cisplatin and regenerative potential give the supporting cells an important role in homeostasis of the organ of Corti and in some specific diseases affecting this structure. CONCLUSION: As well as glial cells provide protection and regeneration to neural tissues, supporting cells may provide the necessary metabolic and electrolitic conditions for hair cells mechanical and bioelectrical function. This opens new possibilities for the treatment of apparently "irreversible" destruction of the inner ear.

Animals↗
PubMed2006

[External auditory canal cholesteatoma as a complication of ear surgery].

External auditory canal cholesteatomas are a rare disease. Their usual clinical appearance is a mass eroding the bony external auditory canal, normally in the inferior or anterior parts, with an intact tympanic membrane and a normal middle ear. A case of this uncommon disease with a review of the scientific literature is presented. Guidelines for the prevention, diagnosis and management are examined.

Aged↗
PubMed2006

Point mutation of an EYA1-gene splice site in a patient with oto-facio-cervical syndrome.

Mutations of the EYA1 gene (8q13.3) are the most common known cause of the branchio-oto-renal dysplasia (BOR), an autosomal dominant disease that includes developmental defects of branchial arch structures, middle and/or inner ear and kidney. The distinction between BOR and other dysplasias, such as oto-facio-cervical syndrome (OFC), is challenged by frequent association of the former to other diverse malformations, and by variable expressivity even within the same family. OFC is characterized by trophic alterations of the facies and shoulder girdle in addition to the malformations seen in BOR. Recent characterization of one OFC patient shed some light on the controversy over whether OFC and BOR are the same disease, and led to the hypothesis that OFC is caused by contiguous deletions of EYA1 and adjacent genes. By contrast, we show here that an OFC patient bears a single-nucleotide substitution in a splice site of EYA1. Our results indicate that not only major rearrangements, but also point mutations altering the EYA1 reading frame, can be found in patients with OFC syndrome.

Abnormalities, Multiple↗
PubMed2004

[Prevalence of the A1555G mutation in the mitochondrial DNA in patients with cochlear or vestibular damage due to aminoglycoside-induced ototoxicity].

OBJECTIVE: To determine the frequency of the A1555G mutation in the mitochondrial genome among Spanish patients with aminoglycoside-induced ototoxicity. PATIENTS AND METHODS: We screened 25 unrelated cases, totalling 39 individuals with cochlear or vestibular damage due to aminoglycoside-induced ototoxicity. This group was made up of 18 subjects from 4 unrelated families with a history of aminoglycoside ototoxicity in more than one relative, 8 subjects from 8 families that also had other relatives with hearing loss in absence of aminoglycoside exposure, and 13 sporadic cases. Among the 13 sporadic cases, there were 3 patients with vestibular involvement. Detection of the A1555G mutation was seen by mean of techniques for molecular diagnosis. RESULTS: The A1555G mutation was identified in all of the individuals from 4 families with aminoglycoside-induced cochlear damage and in 6 of 8 individuals with familial hearing loss. None of the sporadic cases carried the mutation. CONCLUSIONS: A high proportion of patients with cochlear damage due to aminoglycoside ototoxicity and having a familial history of hearing loss, related or not to aminoglycoside exposure, harbor the A1555G mutation.

Adolescent↗
PubMed2003

Development of interface in hydroxyapatite implanted in the middle ear of the rat: a light and scanning microscopy study.

OBJECTIVE: The aim of this work is to study the chronology in the biological covering of the hydroxyapatite bioprostheses in the healthy middle ear of the rat. STUDY DESIGN AND SETTING: Dense hydroxyapatite is implanted into the middle ear of 45 Long-Evans rats, between stapes and tympanic membrane. The sample was divided into 3 groups for morphologic, functional, and chemical studies at 15 days, 3 months, and 6 months after surgery, respectively. RESULTS: The short-term studies reveal that the prostheses is surrounded by a fibrous epithelial tissue referred as the interface; it presents a marked inflammatory reaction that decreases gradually in the medium-term and long-term studies; in this way, we observe a progressive adhesion between implant and the contact tissues. CONCLUSIONS AND SIGNIFICANCE: This model has enabled us to study the cell reaction produced by the contact of the prostheses with bone and soft tissue and their impact on the functional qualities of the prostheses.

Animals↗
PubMed2003

[Retrospective study of 200 cases of nasopharyngeal carcinoma].

Nasopharyngeal carcinoma is frequently diagnosed in advanced stages due to the anatomic characteristics of its site of origin and of the inspecificity of many of its clinical manifestations. However, cure rates are directly related with the early diagnosis. In this study of 200 patients affected by this tumor we analyse the different clinical manifestations, their chronology and their value as early indicators of nasopharyngeal tumour.

Carcinoma, Squamous Cell↗
PubMed2002

Does the serological testing really play a role in the diagnosis immune-mediated inner ear disease?

In order to analyse the clinical presentation and laboratory tests used for the diagnosis of immune-mediated sensorineural hearing loss (IMSNHL) a prospective study was conducted involving 125 patients affected by diverse clinical forms of the disease. The following methods were used: analysis of clinical evolution, pure-tone audiometry, determination of the immunophenotype of peripheral blood lymphocytes, immunoglobulins, complement factors C3 and C4, erythrocyte sedimentation rate, antinuclear autoantibodies (ANA) and heat shock protein 70 and the response to therapy. Levels CD4 (p = 0.03) and CD4CD45RA (p = 0.002) T cells were significantly reduced in patients with sudden sensorineural hearing loss. ANA were found in 34.4% of patients and the incidence of antibodies to HSP-70 was similar in both patients and control subjects. Diagnosis of IMSNHL is still based on clinical impressions as laboratory testing is not sufficiently diagnostic. However, the long-term evolution of IMSNHL presented by the patients included in this study may explain the negative results obtained in the tests. The existence of a typical profile patient, including the clinical course, immunological changes (presence of ANA and detection of abnormalities in T-cell subpopulations) and the response to steroid therapy can facilitate diagnosis. Further investigation to help identify a specific marker characteristic of IMSNHL is required.

Adult↗
PubMed2001

Ventral approach to the rat middle ear for otologic research.

OBJECTIVE: To describe a simple approach to the rat middle ear because there are few clear descriptions of this technique with minimal morbidity and mortality. STUDY DESIGN AND SETTING: Six male Long-Evans rats were used in this study. We designed a cervical approach to the middle ear with the purpose of creating an experimental model of ossiculoplasty that permits the postoperative survival of the animal. RESULTS: It was possible in all cases to visualize the majority of structures of the tympanic cavity: promontory, round window, stapedial artery, stapes, incus, and tympanic membrane. There were no cases of postoperative infection or facial paralysis. CONCLUSIONS AND SIGNIFICANCE: The ventral approach to the rat middle ear is a rapid and simple technique that makes the rat the animal of choice for many otologic investigations.

Animals↗
PubMed2000

Role of viral and Mycoplasma pneumoniae infection in idiopathic sudden sensorineural hearing loss.

Sudden deafness constitutes a challenge in terms of the etiopathogenic diagnosis. The causative origin of sudden deafness usually remains unknown. However, available evidence suggests that viral and Mycoplasma pneumoniae infection could be one factor involved. In order to analyze the incidence of these infectious agents, a microbiology study was carried out during the acute phase of the disease, and during convalescence, in 24 patients (17 men and 7 women; mean age 39.7 years; range 17-63 years) with idiopathic sudden hearing loss (SHL) according to previously published criteria. In the acute phase most of the patients presented IgG antibodies to Epstein-Barr virus (n = 23), herpes simplex virus (n = 24), parainfluenza virus (n = 24), varicella-zoster virus (n = 24) and cytomegalovirus (n = 20). Results obtained from 3 patients suggested the existence of a recent infectious process caused by Mycoplasma pneumoniae (IgM+) in 1 patient, Mycoplasma (IgM+) and influenza A virus (complement fixation titer > 1/64) in another and parainfluenza virus seroconversion (a fourfold higher titer between the acute phase and convalescence) in the third. In conclusion, the low incidence of documented positive serological tests in our series (12.5%) may be due to the presence of pathological situations other than acute infection and does not justify routine serological studies in patients with SHL.

Acute Disease↗
PubMed2000

Immune response and immunopathology of the inner ear: an update.

Immune-mediated inner-ear disease includes clinical conditions associated with unilateral or bilateral rapidly progressive forms of sensorineural hearing loss. A systemic autoimmune disorder can be present in less than one-third of cases. Because of the lack of well defined detection methods to identify immune-mediated processes within the inner ear, and the fact that the human inner ear is not amenable to diagnostic biopsy, there has been great interest in developing animal models. Experimental models of sterile and virus-induced labyrinthitis support the participation of the immune system in the aetiopathogenesis of inner-ear disorders: interleukin-2 emanates from the endolymphatic sac and assists in changing the spiral modiolar vein, as in the expression of intercellular adhesion molecule 1, which allows the egrees of immune cells from the circulation. The formation of a fibro-osseous matrix ultimately results in degeneration of the inner ear. These investigations have allowed us to alter the immune response for the purpose of regulating its intensity and the subsequent damage to patients.

Animals↗
PubMed2000

[Early cellular immune response in experimental labyrinthitis: immunohistochemical study].

Labyrinthitis ossificans is a recently recognized entity with the extending cochlear implant surgery. Up to date there are not so many studies of the cellular response leading the organization of the inflammatory reaction within the cochlea. Immunemediated labyrinthitis is a valid experimental model that allow the knowledge of the cellular infiltration mechanisms within the cochlea. The inner ear communicates with systemic immunity via the circulation by the passage of cells through the spiral modiolar vein (SMV) and its collecting venules in the scala tympani. Inflammatory reaction within the cochlea lead to the formation of fibrotic tissue and bone (osteoneogenesis) inside it and injuring the neurosensory organs of hearing and balance. To test which cells are proliferating early in an inflammatory response, an animal model of Keyhole limpet haemocyanin (KLH) induced labyrinthitis was utilized, showing a granulomatous lesions not previously reported in this experimental model.

Animals↗
PubMed1999

Fibro-osseous lesions of the external auditory canal.

OBJECTIVES: To differentiate a novel type of benign circumscribed bone lesion of the external auditory canal from those described previously, such as exostoses and osteomas. STUDY DESIGN: Information was obtained from computed tomography (CT) images, surgical findings, and pathologic study. METHODS: Five patients (26 to 82 years old) who presented a hard, round, unilateral, skin-covered mass occluding the external auditory canal to varying degrees were studied. A CT study carried out before resection of the lesions by curettage disclosed the absence of a bony connection to the underlying structures. All the tissue specimens underwent pathologic study. RESULTS: CT and surgical findings demonstrated the absence of a connective pedicle. The pathologic findings showed lesions consisting of an osteoma-like bone formation with sparse osteoblastic areas; mature lamellar bone was observed in three cases, bone marrow containing adipose tissue and hematopoietic remnants in two, and a dense, collagenous stroma in another. They all showed irregular trabeculae, bordered by osteoid osteoblasts. In no case was there evidence of a relationship to the cartilaginous tissue or to the bony structures of the external auditory canal. CONCLUSIONS: The data obtained from the clinical, CT, surgical, and pathologic findings suggest the existence of a lesion unlike those previously known, possibly related to ossifying reactions in other parts of the organism.

Adult↗
PubMed1998

Prognostic significance of natural killer cell activity in patients with laryngeal carcinoma.

BACKGROUND: For laryngeal carcinoma, the present TNM clinical staging system does not seem completely satisfactory as a guide for providing a prognosis for survival. We believe that natural killer cell activity would probably have a role in a more reliable system. Therefore, we analyzed the disease outcome with previously untreated epidermoid carcinoma of the larynx, evaluating classic clinical and pathologic factors, as well as natural killer cell activity in peripheral blood samples of the patients. OBJECTIVES: To determine the level of natural killer cell activity in patients with laryngeal carcinoma and to analyze the prognostic value of this finding when associated with other clinical and pathologic variables. DESIGN: Prospective cohort study of surveillance of laryngeal cancer. Mean follow-up of 42.8 months. SETTINGS: Tertiary care referral center and ambulatory and hospitalized care. PARTICIPANTS: We compared 81 men (mean age, 62.4 years; range, 35-89 years) with laryngeal carcinoma with 44 healthy men serving as control subjects (mean age, 57.6 years; range, 37-82 years). RESULTS: Natural killer cell activity was significantly reduced in patients who had died of cancer-related causes in comparison with tumor-free survivors. Overall actuarial survival differed significantly in histologically assessed nodal involvement and low natural killer cell activity. Use of the Cox proportional hazards regression model showed that the factors that seem to have a prognostic effect on survival are histologically determined nodal involvement and low natural killer cell activity. CONCLUSIONS: These results support the prognostic significance of the determination of pretreatment natural killer cell activity in peripheral blood samples from patients with laryngeal carcinoma and suggest that assessment of adding such a determination to the current tumor staging system is advisable.

Adult↗