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Biomedical subjects

F W Albers

Publications and source records attributed to F W Albers.

At least 19 recordsLinked to original sources
PubMed2001

Air-flow resistances of silicone rubber voice prostheses after formation of bacterial and fungal biofilms.

Laryngectomized patients use silicone rubber voice prostheses to rehabilitate their voice. However, biofilm formation limits the lifetime of voice prostheses by causing leakage or an increased air-flow resistance and the prosthesis has to be replaced. To determine which bacterial or yeast strains, isolated from explanted voice prostheses, contribute most to increases in air-flow resistance of silicone rubber voice prostheses, biofilms consisting of either a bacterial or a yeast strain were grown on voice prostheses in the artificial throat model. The effects of these biofilms on air-flow resistances were determined by calculating the difference in air-flow resistance of the individual voice prosthesis as covered with a 7-day-old biofilm with the situation prior to biofilm formation. Conspicuously, voice prosthetic biofilms formed by the bacterial strains Staphylococcus aureus GB 2/1 and Rothia dentocariosa GBJ 41/25B and their excreted organic matter showed larger increases in air-flow resistance (more then 30 cm H(2)O.s/L) than biofilms formed by Candida species. This is contrary to the literature, where there seems to be agreement that Candida species are mainly responsible for clinical failure of silicone rubber voice prostheses.

Bacteria↗
PubMed2001

Biofilm formation and design features of indwelling silicone rubber tracheoesophageal voice prostheses--an electron microscopical study.

After total laryngectomy, voice can be restored with a silicone rubber tracheoesophageal voice prosthesis. However, biofilm formation and subsequent deterioration of the silicone material of the prosthesis will limit device life by impairing valve function. To simulate the natural process of biofilm development under dynamic nutrient conditions, a modified Robbins device was used to evaluate the biofilm-related valve dysfunction of the Groningen, Provox2, Blom-Singer indwelling, and VoiceMaster voice prostheses. Obstruction of the semicircular slit-valved Groningen prosthesis leading to increased airway resistance was caused not only by a buildup of deposits on the esophageal flange and valve hat, but also by accumulation of deposits on the semicircular valve seating. The hinged flap valved Provox2 and indwelling Blom-Singer prostheses failed to close sufficiently because of biofilm formation on the valve seating. The esophageal flange of the VoiceMaster prosthesis was affected, but the tripod structure of the ball valve was fully colonized up to the titanium sleeve, which interfered with proper valve opening and closure. These findings on biofilm formation could be used for the further development and modification of critical design features of voice prostheses to facilitate tracheoesophageal speech.

Bacterial Adhesion↗
PubMed2001

Perilymphatic pressure measurement in patients with Menière's disease.

The MMS-10 Tympanic Displacement Analyser is a new device for measuring perilymphatic pressure in humans. This instrument was used in 70 patients with Menière's disease (44 affected ears) and a group of 50 young normal hearing subjects. No significant differences in perilymphatic pressure measurements were found between the groups. Although measurement parameters showed large inter-individual variation in a subgroup of 25 patients, the intra-individual correlation in the subgroup was good. In patients with Meniere's disease no relationship was found between perilymphatic pressure, hearing thresholds, blood pressure, gender or age. There was no difference between unilaterally and bilaterally affected patients.

Adult↗
PubMed2001

Pure-tone and speech audiometry in patients with Menière's disease.

The aim of this study was to reinvestigate many of the claims in the literature about hearing loss in patients with Menière's disease. We carried this out on a well-defined group of patients under well-controlled circumstances. Thus, we were able to find support for some claims and none for many others. As part of a diagnostic protocol, pure-tone and speech audiometry was performed on 111 patients with Menière's disease according to the 'Definition Menière Groningen'. This was a prospective clinical cohort study. Affected ears of patients suffering from Menière's disease show reduced hearing, both in pure-tone and in speech audiometry. A classification method was devised to determine audiogram shape in an objective manner. The results of this method indicate that affected ears more frequently show 'low' or 'low + high' hearing losses (P = 0.006). The shape of the hearing loss does not depend on the duration of the affection of the disease. In combination with the fact that the average hearing loss does not correlate with the duration of the disease, this leads to the conclusion that, if a classification of the hearing loss in Menière's disease is possible, such a classification cannot be connected to the duration. This conclusion is further supported by the fact that no relationship is found between the duration of the disease and the classification of the hearing loss over the 3 months before hospital admission, as given by the patients in a questionnaire. A relationship between the (objective) audiometric data and the (subjective) classification of the hearing loss by the patient seems to be present, but is not very strong. Correlations between pure-tone and speech audiometry are present as in non-Menière ears (r = 0.899, P < 0.001), and no indications are found of reduced speech discrimination relative to the expectation based on pure-tone loss. The audiogram shape does not appear to play any additional role in speech discrimination (in addition to the influence of the average pure-tone loss).

Adult↗
PubMed2001

The vestibular evoked response to linear, alternating, acceleration pulses without acoustic masking as a parameter of vestibular function.

In this study, short latency vestibular evoked potentials (VsEPs) were recorded in five guinea pigs in response to alternating linear acceleration pulses with and without acoustic masking. A steel bolt was implanted in the skull and coupled to a shaker. Linear acceleration pulses (n = 400) in upward, downward or alternating directions were given, with a peak acceleration of 4g after 0.5 msec. Tests were repeated with acoustic masking, after modiolus destruction and after application of KCl in the vestibule. Stimuli of the vestibular nerve were recorded with a platinum electrode in the bony facial nerve canal in the bulla. Unilateral linear acceleration showed a shallow plateau at 0.5 msec, which disappeared with alternating acceleration impulses and after modiolus destruction. Therefore all further tests were done with alternating impulses. After a latency time of 0.8 msec a multiwave response was seen, with a first positive peak P1 at 1.16 ms. These were followed by other positive and negative peaks (N1, P2, N2, P3, N3). With the elimination of cochlear influences by using acoustic masking, P1 remained stable, while subsequent peaks were altered or eliminated. After modiolus destruction, the P1 peak remained, although with a smaller amplitude due to vestibular damage. After application of a saturated KCl solution in the vestibule all responses, including P1, disappeared, thus confirming the vestibular origin of these responses. We conclude that the onset latency of the VsEP and the peak latency and level of the first positive peak P1 in response to alternating linear acceleration pulses without acoustic masking, measured in the facial canal, are good and stable parameters of vestibular function in guinea pigs.

Animals↗
PubMed2001

Perilymphatic and endolymphatic pressure in the guinea pig after distal dissection of the endolymphatic sac.

HYPOTHESIS: The study was designed to investigate whether endolymphatic pressure exceeds perilymphatic pressure in an endolymphatic hydrops model with a partially functioning endolymphatic sac. BACKGROUND: Previous investigations of perilymphatic and endolymphatic pressure measurements during endolymphatic hydrops were done in a classic endolymphatic hydrops model, with a surgically blocked endolymphatic duct and sac. This model, in contrast to the clinical situation of Meniere's patients, totally lacks the functional contribution of the endolymphatic sac. METHODS: In the guinea pig, a partially functioning endolymphatic sac was created via dissection of the distal portion of the sac from the sigmoid sinus. Three (n = 5) and 6 months (n = 3) later, perilymphatic and endolymphatic pressures were measured consecutively using a WPI 900A micropressure system. RESULTS: It was observed that damage to the distal part of the endolymphatic sac caused endolymphatic hydrops in 58% of the cases. The hydrostatic pressure in hydropic ears did not differ from that of control ears. There was no pressure difference between the perilymphatic and endolymphatic compartments in ears with endolymphatic hydrops. The endocochlear potential in ears with hydrops was statistically significantly decreased (p < 0.002). CONCLUSION: In a hydrops model developed to be more comparable to the histopathologic appearance of Meniere's disease in the inner ear, no hydrostatic pressure difference was measured between the perilymphatic and endolymphatic spaces. The only functional difference from control ears we found was a decreased endocochlear potential.

Animals↗
PubMed2001

Sensory cell damage in two-phase endolymphatic hydrops: a morphologic evaluation of a new experimental model by low-voltage scanning techniques.

HYPOTHESIS: The aim of this study was to create a more dynamic animal model of Ménière's disease combining multiple causes, such as the role of endocrine factors and endolymphatic sac dysfunction, that may mimic the fluctuant characteristics of Ménière's disease. BACKGROUND: Endolymphatic hydrops remains to be considered a pathologic substrate in the etiology of Ménière's disease. The classic guinea pig model of inducing hydrops by total destruction of the endolymphatic sac is a nonphysiologic rigid model of Ménière's disease. METHODS: The authors developed the two-phase endolymphatic hydrops model by inducing hydrops by mild chronic endolymphatic sac dysfunction, in combination with increased endolymph production by aldosterone. Sensory cell damage was evaluated by low-voltage field emission scanning microscopy. RESULTS: This study describes a wide spectrum of morphologic effects of the outer hair cells in radial gradients, in which most effects were observed in the third to second row of outer hair cells, and longitudinal gradients in which the most severe effects were observed in the apical turns. Most affected were the ears that underwent distal endolymphatic sac dissection followed by the administration of aldosterone. Damaging effects proceeded from degeneration and absence of short stereocilia of outer hair cells and even some inner hair cells in the apical turns, to stereociliary disarrangement and atrophy, followed by degeneration and absence of outer hair cells, which were replaced by supporting cells. CONCLUSION: The two-phase endolymphatic hydrops model seems to represent a functional model that may mimic the fluctuant characteristics of Ménière's disease and emphasizes the influence of multiple and coexisting hydrops-inducing influences.

Animals↗
PubMed2001

Biofilm formation on voice prostheses: in vitro influence of probiotics.

In order to determine the influence of probiotic bacteria on biofilm formation on Groningen and Provox 2 voice prostheses in an artificial throat, we grew biofilms on both types of voice prostheses and exposed them 3 times daily to a probiotic bacterial suspension. As a control, we perfused an artificial throat with phosphate-buffered saline solution. Perfusion with Lactococcus lactis 53 suspension reduced the percentage numbers of bacteria and yeasts, respectively, on the Groningen prostheses to 17% and 22% and on the Provox 2 prostheses to 19% and 45%, compared to the number of colony-forming units on the control prosthesis, which was set at 100%. A suspension of Streptococcus thermophilus B reduced the percentage numbers of bacteria and yeasts, respectively, on the Groningen prostheses to 53% and 33% and on the Provox 2 prostheses to 14% and 0%, as compared to the control prosthesis. All other probiotic strains tested caused some reduction in the percentages of bacteria or yeasts, but strong differences between the types of prostheses were observed. In conclusion, L. lactis 53 and S. thermophilus B strongly reduce the occurrence of yeasts and bacteria in voice prosthetic biofilms.

Biofilms↗
PubMed2001

Dynamics of inner ear pressure change caused by intracranial pressure manipulation in the guinea pig.

Previous studies have shown that pressure changes in the cerebrospinal fluid compartment are transmitted to the inner ear. The main route for pressure transfer is the cochlear aqueduct. about which little is known with regard to its dynamic properties. In the present study, sudden intracranial pressure changes (square waves and short pulses) were created in guinea pigs by means of an electronically controlled infusion system. Simultaneously with pressure manipulation, hydrostatic pressure was monitored in both the peridural space and the perilymphatic compartment of the inner ear. The onset of an inner ear pressure change following manipulation of intracranial pressure was immediate. Inner ear pressure increased or decreased without a measurable time lag, and equalized within a few seconds. During square wave intracranial pressure manipulation, inner ear pressure equalized somewhat more slowly after pressure increase than after pressure decrease. To a first approximation, the pressure equalization curves for the inner ear could be fitted with a single exponential function, rising or falling with a time constant in the range 1-3 s, and the system can be described as a low-pass filter composed of a constant compliance and a constant flow resistance. Detailed analysis, however, showed small deviations from a purely exponential recovery process. With a more complicated (non-linear) model, almost perfect fits to the inner ear pressure equalization curves could be obtained. This non-linearity may be a consequence of the dependence of the compliance and, or flow resistance on pressure.

Animals↗
PubMed2000

Measurement of the mechanical compliance of the endolymphatic compartments in the guinea pig.

During injection of artificial endolymph into scala media of the guinea pig, fluid pressure was simultaneously measured in endolymph and perilymph with micropipettes. Pressure differences in the order of 10 Pa could reproducibly be measured upon injection of 2-4 microl of artificial endolymph with a rate of 50 nl/s. Injection of larger volumes damaged the endolymphatic system. From the results, values were derived for the compliances of the membranes surrounding scala media and the vestibular part of the endolymphatic system. The shape of the pressure-time curve during and between repetitive injections of fluid could well be described with a two-component model for the endolymphatic system, consisting of two compartments with compliant walls, connected through a flow resistance. With this model, a larger compliance was found for the second compartment (vestibular part of endolymphatic system) than for the first compartment, into which fluid was injected (scala media).

Animals↗
PubMed2000

Monitoring inner ear pressure changes in normal guinea pigs induced by the Meniett20.

The inner ear fluid pressure of guinea pigs was measured during a series of complex oscillating middle ear pressure changes induced by the Meniett20 (Pascal Medical, Sweden), a possible therapeutic pressure generator to be used by patients with Meniere's disease. Middle ear pressure changes were transferred instantly to the inner ear, although inner ear pressure declined while middle ear pressure stayed relatively stable. An average undershoot of -1.0 cm H2O with respect to the steady-state pressure was seen after application of a pressure pulse, which was released in a few seconds. The results did not fully comply with a simple linear model in which a constant flow resistance between the inner ear and cerebrospinal space was assumed.

Animals↗
PubMed2000

Biofilm formation on voice prostheses: influence of dairy products in vitro.

Laryngectomized patients use silicone rubber voice prostheses to regain their speech, however, the lifetime of these devices is limited due to biofilm formation. Following anecdotal evidence, the influence of various dairy products on biofilm formation on voice prostheses was studied, using the artificial throat-model. Biofilms were grown on Groningen and Provox2 voice prostheses by inoculating two artificial throats with the total microflora isolated from an explanted Groningen voice prosthesis. After 3 days, one throat was perfused three times daily with 650 ml dairy product; the other was perfused with phosphate buffered saline, used as a control. After 12 days the microflora on each voice prosthesis was determined. Perfusion of the artificial throat with buttermilk three times daily for 9 days reduced the amount of bacteria and yeasts in the biofilm on Groningen voice prostheses to 3% and 15% of the control, respectively. These effects were not observed with a pasteurized conservable buttermilk product. Yakult fermented milk drink, Mona mild yoghurt, Mona vifit yoghurt, semi-skimmed milk and low-fat yoghurt reduced the amount of bacteria by various degrees, ranging from 12% (Yakult) to 88% (Mona mild) of the control, but these products did not inhibit, and sometimes even stimulated, yeast growth. A combination of buttermilk and Yakult did not show a synergistic effect, as expected. Effects for the Provox2 voice prosthesis were less pronounced. These in vitro experiments in the artificial throat demonstrated that the formation of the biofilm on voice prostheses can be lessened by the daily use of certain dairy products, of which buttermilk had the strongest inhibitory effect, followed by Yakult.

Animals↗
PubMed2000

Antimicrobial activity of synthetic salivary peptides against voice prosthetic microorganisms.

OBJECTIVES: To investigate whether synthetic salivary antimicrobial peptides have an inhibitory effect on the growth of bacteria and yeasts isolated from used silicone rubber voice prostheses. METHODS: The antimicrobial activities of six synthetic salivary peptides (histatin 5, dhvarl, dhvar4, dhvar5, lactoferrin b 1730 [LFb 17-30], and cystatin S1-15) at concentrations of 2 and 4 mg/mL were determined against different oropharyngeal yeast (four) and bacterial (eight) strains and against a "total microflora" isolated from explanted voice prostheses using agar diffusion tests. The spectrum of susceptible microorganisms was determined qualitatively. RESULTS: Histatin 5 and cystatin S1-15 did not show any antimicrobial activity against the microorganisms involved in this study. Dhvar1 was active against some of the oropharyngeal microorganisms tested, including the yeast strains, but not against Rothia dentocariosa, Staphylococcus aureus, Escherichia coli, and the total microflora Dhvar4 was active against all microorganisms tested, including the total microflora. Dhvar5 lacked activity against E coli and the total microflora LFb 1730 did not inhibit the growth of any of the yeast strains involved and showed only minor activity against some of the bacterial strains. LFb 1730 slightly inhibited the growth of the total microflora from an explanted prosthesis. CONCLUSIONS: The synthetic salivary peptide dhvar4 has a broad antimicrobial activity against all microorganisms that are commonly isolated from explanted voice prostheses, including yeasts. Therewith, it may represent a useful drug, as an alternative for antibiotics and antimycotics employed in various ways to prolong the lifetime of voice prostheses in laryngectomees.

Bacteria↗
PubMed2000

Cineradiography of the pharyngoesophageal segment in postlaryngectomy patients.

The use of tracheoesophageal voice prostheses has gained wide acceptance in the field of vocal rehabilitation after total laryngectomy. In a randomized study with 3 arms, alaryngeal speech proficiency was assessed in 60 postlaryngectomy patients: 20 patients underwent primary unilateral pharyngeal myotomy, 21 patients underwent neurectomy of the pharyngeal plexus in addition to pharyngeal myotomy, and 19 patients did not undergo an additional surgical procedure. Pharyngoesophageal (PE) dynamics were examined during esophageal and tracheoesophageal speech. A single vibrating PE segment was seen in good alaryngeal speakers. Hypertonicity, spasm, strictures, and hypotonicity of the PE segment were correlated significantly with poor or moderate alaryngeal speech. Unilateral myotomy with or without unilateral neurectomy prevented hypertonicity or spasm of the PE segment. The acquisition of alaryngeal speech did not differ significantly between the 2 groups who had undergone an additional surgical procedure. Evaluation of anatomic and physiological factors may be helpful in subsequent clinical management to achieve effective alaryngeal speech.

Adult↗
PubMed2000

Preliminary observations on influence of dairy products on biofilm removal from silicone rubber voice prostheses in vitro.

We determined oropharyngeal biofilm removal from silicone rubber voice prostheses in an artificial throat after perfusion with different commercially available dairy products, including buttermilk, Lactobacillus casei Shirota fermented milk (Yakult, Yakult Netherlands BV, Almere, The Netherlands), low-fat milk, and three types of yogurt. Buttermilk removed both yeasts and bacteria from biofilms on voice prostheses, but this was not observed with a pasteurized buttermilk product. Some of the other products, most notably Yakult fermented milk drink, reduced the number of bacteria, whereas growth of yeasts in the biofilms was not inhibited. This study demonstrates that there may be health benefits associated with the consumption of certain dairy products when applied to the upper digestive tract.

Animals↗
PubMed2000

Noninvasive perilymphatic pressure measurement in patients with Ménière's disease and patients with idiopathic sudden sensorineural hearing loss.

OBJECTIVE: Inner ear disorders are proposed to be affected by changes in inner ear hydrostatic pressure. In humans, the perilymphatic hydrostatic pressure can be assessed in a noninvasive way with the MMS-10 Tympanic Displacement Analyser. In this study, measurements were performed in patients with Ménière's disease and patients with idiopathic sudden sensorineural hearing loss (ISSHL), and the results were compared with those of normal hearing ears. The measurement technique has been evaluated as a possible additional diagnostic tool for Ménière's disease or ISSHL. STUDY DESIGN: The hydrostatic perilymphatic pressure was measured noninvasively with the MMS-10 Tympanic Displacement Analyser. SETTING: Department of Otorhinolaryngology at the University Hospital. PATIENTS: Seventy-seven patients with Ménière's disease, 28 patients with ISSHL, and 50 normal hearing subjects. INTERVENTION: Diagnostic. MAIN OUTCOME MEASURE: Significant differences of perilymphatic pressure measurement results, represented by the measurement parameters Vi and Vm, in affected, nonaffected, and normal hearing ears. RESULTS: On average, the measurement results showed no significant differences between affected (by Ménière's disease or ISSHL), nonaffected, and normal hearing ears. CONCLUSIONS: In affected ears, perilymphatic pressure measured noninvasively did not differ significantly from the pressure in nonaffected and normal hearing ears. The tympanic membrane displacement technique cannot be considered an additional tool to confirm or reject the diagnosis of Ménière's disease or ISSHL.

Adolescent↗
PubMed1999

Intratemporal and intracranial complications of acute suppurative otitis media in children: renewed interest.

In recent years, a rise in the incidence of intratemporal and intracranial complications of acute otitis media (AOM) has been mentioned in the literature. Lack of a well-developed immune system and difficulties in diagnosing AOM, can account for part of the rise in the incidence of complications of purulent middle ear infections in young children. Antibiotic treatment of AOM is certainly not an absolute safeguard against the development of complications. Antibiotic therapy may have a masking effect on significant signs and symptoms of complications, causing delay in diagnosis. Myringotomy, especially in young children, should not be forgotten for drainage and to provide material for culture. Increased virulence of the causative pathogens cannot be ruled out, but to date there is no evidence suggesting it. We have to maintain a high level of clinical awareness. If there is insufficient improvement of the patient with the appropriate conservative treatment, radioimaging followed by the necessary surgical procedures should be performed.

Acute Disease↗