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Biomedical subjects

C Beck

Publications and source records attributed to C Beck.

At least 73 records · Page 4Linked to original sources
PubMed1994

[Effects of therapy of laryngeal and hypopharyngeal cancers on eustachian tube function].

In a prospective investigation Eustachian tube function was tested before and after surgery and irradiation of patients suffering from carcinoma of the larynx or hypopharynx. Passive and active tubal parameters were determined using the dual-impedance method in a pressure chamber. In this test, passive tubal function is described by the spontaneous opening and closing characteristics of the tube by an overpressure in the middle ear. Active tubal parameters are determined by the facility of the tube to equalize an over- and underpressure in the middle ear by swallowing. Statistic evaluation was performed with Student's t-test. There were no significant alterations of passive or active tubal function after neck dissection with or without surgery of the primary tumour. On the other hand we observed significant deterioration of all tubal parameters immediately after a series of fractionated percutaneous telecobalt therapy (60 Gy). 2 out of 18 patients developed unilateral middle ear effusion during irradiation which was reversible within 6 months. In most patients we observed a total or at least partial restitution of passive tubal parameters during this time, which was statistically significant. The active tubal function was of minor reversibility. Whereas the facility to equalize a positive pressure in the middle ear was quite good after 6 months, only few patients were able to equalize a negative pressure. The temporary deterioration of passive tubal function may be caused by a marginal implication of the tube at the edge of the irradiation field and by increased lymphatic pressure in tubal tissue following a radiogenic swelling of the lymphatic vessels of the neck.(ABSTRACT TRUNCATED AT 250 WORDS)

Combined Modality Therapy↗
PubMed1994

On the localization of voltage-sensitive calcium channels in the flagella of Chlamydomonas reinhardtii.

This study was undertaken to prove that voltage-sensitive calcium channels controlling the photophobic stop response of the unicellular green alga Chlamydomonas reinhardtii are exclusively found in the flagellar region of the cell and to answer the question as to their exact localization within the flagellar membrane. The strategy used was to amputate flagella to a variable degree without perturbing the electrical properties of the cell and measure flagellar currents shortly after amputation and during the subsequent regeneration process. Under all conditions, a close correlation was found between current size and flagellar length, strongly suggesting that the channels that mediate increases in intraflagellar calcium concentration are confined to and distributed over the total flagellar length. Bald mutants yielded tiny flagellar currents, in agreement with the existence of residual flagellar stubs. In the presence of the protein synthesis inhibitor cycloheximide, flagellar length and flagellar currents also recovered in parallel. Recovery came to an earlier end, however, leveling off at a time when in the absence of cycloheximide only half maximal values were achieved. This suggests the existence of a pool of precursors, which permits the maintenance of a constant ratio between voltage-sensitive calcium channels and other intraflagellar proteins.

Animals↗
PubMed1994

The ccoNOQP gene cluster codes for a cb-type cytochrome oxidase that functions in aerobic respiration of Rhodobacter capsulatus.

The genes for a new type of a haem-copper cytochrome oxidase were cloned from Rhodobacter capsulatus strain 37b4, using the Bradyrhizobium japonicum fixNOQP gene region as a hybridizing probe. Four genes, probably organized in an operon (ccoNOQP), were identified; their products share extensive amino acid sequence similarity with the FixN, O, Q and P proteins that have recently been shown to be the subunits of a cb-type oxidase. CcoN is a b-type cytochrome, CcoO and CcoP are membrane-bound mono- and dihaem c-type cytochromes and CcoQ is a small membrane protein of unknown function. Genes for a similar oxidase are also present in other non-rhizobial bacterial species such as Azotobacter vinelandii, Agrobacterium tumefaciens and Pseudomonas aeruginosa, as revealed by polymerase chain reaction analysis. A ccoN mutant was constructed whose phenotype, in combination with the structural information on the gene products, provides evidence that the CcoNOQP oxidase is a cytochrome c oxidase of the cb type, which supports aerobic respiration in R. capsulatus and which is probably identical to the cbb3-type oxidase that was recently purified from a different strain of the same species. Mutant analysis also showed that this oxidase has no influence on photosynthetic growth and nitrogen-fixation activity.

Aerobiosis↗
PubMed1993

[Effects of a change in environmental pressure on spontaneous nystagmus in patients with cochleovestibular diseases].

Cochlear and vestibular effects of variation of middle ear pressure have been discussed for more than 50 years. In 1975, Densert reported on temporary improvement of hearing threshold in patients suffering from Ménière's disease after reduction of air pressure in a pressure chamber. One year later Ingelstedt observed reduction of spontaneous nystagmus under this condition. The transmission of relative overpressure from the middle ear to the labyrinth with consecutive decongestion of the hydropic endolymphatic system to the saccus was thought to be the cause of this phenomenon. Meanwhile a direct effect of labyrinthine pressure on the activity of the inner ear and labyrinth in healthy subjects and animals has been described. In order to gain further information on the phenomenon observed by Densert and Ingelstedt we performed investigations on patients suffering from several cochleovestibular diseases. Chamber pressure was altered and simultaneous electronystagmographic recording was performed. As a striking result, we observed a reduction of the pathological spontaneous nystagmus in a majority of patients with vestibular damage during and after the reduction of chamber pressure. Many of these subjects showed a partial restitution of nystagmus if the chamber pressure was increased again. This observation was made in patients with Méni ere's disease, vestibular neuritis and sudden hearing loss with vestibular involvement. Hence, we conclude that this phenomenon is not specific for Ménière's disease. A transmission of middle ear pressure to the labyrinth may be an explanation of our observations.

Air Pressure↗
PubMed1993

Cognitively impaired elders. Using research findings to improve nursing care.

1. Cognitive changes may be similar in people with Alzheimer's disease, but each person loses abilities differently, and each individual responds differently to interventions. 2. Assessment of cognitive function is needed in order to design appropriate interventions that will be specific in facilitating independence in cognitively impaired elders. 3. Research findings suggest that functional ability in cognitively impaired elders can be maximized by assessing cognitive abilities and using this information to tailor specific interventions that will facilitate independence.

Aged↗
PubMed1993

[Subablative gentamycin therapy in Menière's disease].

We have treated 20 patients suffering from unilateral Morbus Meniere (2 x 12 mg gentamicin for 7 days). These patients were controlled for 24 months. In 95% we regarded a complete or substantial control of definitive spells ("American Committee on Hearing and Equilibrium guidelines for reporting treatment results in Meniere's disease", Otolaryngol. Head and Neck Surg. 10/19-85). Only 1 patient with pretherapeutic equal caloric response showed a post-therapeutic destroyed vestibular apparatus on the treated ear. In the other 7 patients (35%), who had a loss of vestibular function after therapy, there was an already pretherapeutic more or less noticeable caloric hypoexcitability. It is possible to induce an only subablative damage with a clinical success in 95%.

Audiometry, Pure-Tone↗
PubMed1993

Classification of autonomic disorders.

Recent advances in our understanding of the pathophysiology of cardiovascular regulation and the metabolism of catecholamines have enabled us to develop an improved system of classification of autonomic disorders. Patients with autonomic impairment, clinically unassociated with other neurological abnormalities, are considered to have the Bradbury-Eggleston syndrome (idiopathic orthostatic hypotension, pure autonomic failure). Individuals whose autonomic failure is accompanied by degeneration in other neurological systems are classified as having the Shy-Drager syndrome (multiple system atrophy with autonomic failure). Patients in whom a deficiency of the enzyme dopamine-beta-hydroxylase is present from birth have many features suggestive of the Bradbury-Eggleston syndrome but manifest normal sweating and biochemically have an elevated plasma and urinary dopamine level. Recognition of these individuals is of particular importance because they are uniquely responsive to treatment with oral dihydroxyphenylserine (L-DOPS). A fourth disorder is baroreflex failure; this disorder is usually due to surgery, trauma, radiation or other injury to the ninth or tenth cranial nerves or the medullary nuclei which their fibers innervate. Patients with baroreflex failure have oscillations between hypertension and hypotension, but these alterations are poorly correlated with posture. Very high levels of plasma norepinephrine are found during the hypertensive phase of baroreflex failure. Baroreflex failure is generally responsive to treatment with clonidine. In conclusion, the diagnosis and therapy of autonomic disorders has improved due to the more precise taxonomy now current.

Autonomic Nervous System Diseases↗
PubMed1992

Confirmation of linkage of benign familial neonatal convulsions to D20S19 and D20S20.

Benign familial neonatal convulsions (BFNC) is an idiopathic form of epilepsy beginning within the first six months of life. Its genetic origin and autosomal dominant mode of inheritance have been suspected since its first description. Recently, the BFNC gene has been localised within chromosome 20q in one large pedigree. For the first time, we confirm here (with D20S19 and D20S20) the close linkage of BFNC to chromosome 20q in six French pedigrees. In addition, the existence in these families of several cases of febrile convulsions (FC), another epileptic syndrome with an autosomal dominant genetic component, led us to study the possibility of a genetic background identical to BFNC. Our results suggest the existence of different susceptibility genes for BFNC and FC.

Blotting, Southern↗
PubMed1992

Disruptive behaviors of a cognitively impaired nursing home resident.

The descriptive case study of a 71-year-old man with Primary Degenerative Alzheimer's Dementia identifies and describes specific disruptive behaviors exhibited by a demented, disruptive nursing home resident and the biopsychosocial characteristics of these behaviors. The Disruptive Behavior Scale (Beck, Baldwin, Heithoff, & Cuffel, 1990) measured disruptive behaviors. Data collected included chart review, interviews, testing, and observation. The majority of observed disruptive behaviors fell under four categories: (1) walks aimlessly, (2) makes repetitive noises, (3) uses obscene/profane language, and (4) makes repetitive movements. Staff members and chart notes reported the same categories, except for "makes repetitive noises." All aggressive behavior toward the staff occurred during assistance with activities of daily living (ADLs).

Activities of Daily Living↗
PubMed1992

[Laryngeal cancer following gunshot injury and paraffin injection].

Subcutaneous and submucosal injections of paraffin were a wide-spread technique in plastic and reconstructive surgery during the early decades of this century. Intralaryngeal injections were applied to patients suffering from paralysis of one vocal cord or a defect resulting from perforating trauma, intending improvement of the voice. This method was widely abandoned within the fifties when severe complications like foreign-body granuloma and carcinoma developed in patients undergoing paraffin injections. The development of cancer after a trauma is a common question in expert reports. We report the case of a patient who developed carcinoma of the vocal cord 49 years after perforation of the larynx by a shot with consecutive injection of paraffin. The relationship between trauma, injections of paraffin and cancer is discussed and consequences on diagnostics and treatment of risk patients are outlined.

Aged↗