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Biomedical subjects

M Tigges

Publications and source records attributed to M Tigges.

At least 19 recordsLinked to original sources
PubMed2000

Functional imaging of vocal fold vibration: digital multislice high-speed kymography.

For the diagnosis of voice disorders, and especially for the classification of hoarseness, direct observation of vocal fold vibration is essential. Furthermore, a quantitative description of the movement of the vocal fold becomes increasingly necessary to document and compare findings as well as the progression of speech therapy. On the base of digital high-speed sequences of vocal fold vibration, multiple "functional images"-also called digital kymograms-are obtained using image- and signal-processing algorithms. Digital kymograms can serve as a powerful aid for visualization, description, and classification of vocal fold vibration and as an intermediate step for image interpretation by biomechanical modeling. This visualization technique will be discussed and compared to other techniques currently available: videokymography and videostroboscopy. The technique is applied to several clinical examples: aperiodic processes (phonation onset), irregular vocal fold vibration (paralysis of the recurrent nerve), particular vibration modes (anterior-posterior modes), and running speech.

Humans↗
PubMed1999

High-speed digital imaging of neoglottic vibration after total laryngectomy.

OBJECTIVES: To establish the applicability of digital high-speed imaging in studying neoglottic mucosal vibration after total laryngectomy and to perform a structured evaluation of the recordings using a standardized assessment form to gain insight about the anatomical and morphologic characteristics of the neoglottis. DESIGN: Evaluation of a new clinical tool and description of clinical disorders in a patient survey. SETTING: The Netherlands Cancer Institute, Amsterdam. PATIENTS: Forty-six patients who underwent laryngectomy, 36 who underwent standard total laryngectomy and 10 who underwent a partial or total pharynx reconstruction (ie, myocutaneous pectoralis major flap [n = 4], free radial forearm flap [n = 2], tubed gastric pull-up [n = 3], and full gastric pull-up [n = 1]). INTERVENTION: Digital high-speed imaging, using a 90 degrees rigid laryngoscope, of the neoglottic vibration in prosthetic tracheoesophageal speakers after total laryngectomy. MAIN OUTCOME MEASURES: Digital high-speed imaging might overcome some of the problems of stroboscopy in studying irregular voices and could, therefore, be expected to give more insight into the anatomical and morphologic characteristics of the neoglottis. RESULTS: Digital high-speed recordings could be obtained in 44 of 46 patients. Using a structured evaluation form, a wide variability in anatomical and morphologic features could be established. CONCLUSIONS: Digital high-speed imaging appeared to be a useful tool in studying the irregular vibrations of the neoglottis. Evaluation by the structured evaluation form gives a good idea about the wide variability in anatomical and morphologic features of the neoglottis.

Aged↗
PubMed1999

Effects of muscarinic cholinergic receptor antagonists on postnatal eye growth of rhesus monkeys.

PURPOSE: To study a potential role for muscarinic receptors in the inhibition of deprivation-induced excessive axial elongation and myopia in a monkey model. METHODS: The right eyes of 20 newborn rhesus monkeys were occluded with a black contact lens. In seven monkeys each, either atropine or pirenzepine was topically applied daily to the occluded eyes. The nonoccluded fellow eyes and both the occluded and nonoccluded fellow eyes of another six monkeys were treated with vehicle solution. RESULTS: After 33 to 39 weeks, in 5 monkeys of the vehicle group, occluded eyes were longer and the myopic shift significantly greater than in the nonoccluded fellow eyes. In six atropine-treated monkeys, axial length and reduction of the initial hyperopia of occluded and nonoccluded fellow eyes were not different statistically. The myopic shift of the occluded eyes was significantly smaller than in the vehicle-treated occluded eyes. In the pirenzepine-treated group, axial length of the occluded eyes was similar to the nonoccluded eyes of controls and the occluded eyes of atropine-treated monkeys. There was a trend of pirenzepine to reduce the myopic shift of the occluded eye. No effect of atropine or pirenzepine was noted on muscarinic receptor density in retina, brain, or heart, but a small increase was observed in iris + ciliary body. CONCLUSIONS: The drug treatment results implicate muscarinic receptors in postnatal eye growth regulation. Because of interanimal differences our data do not indicate whether nonselective or selective muscarinic blockade is more effective in reducing deprivation-induced myopia.

Animals↗
PubMed1999

Emmetropization in the rhesus monkey (Macaca mulatta): birth to young adulthood.

PURPOSE: To provide baseline measurements on the postnatal changes in refractive error, corneal curvature, and axial elongation of the eyes of normal monkeys. Little is known about the course of normal eye growth from birth to adolescence, particularly how refractive parameters co-vary during development. In animal models of ametropia, usually one eye is manipulated and the fellow eye serves as a control. However, given individual differences, and without baseline data, it is impossible to determine whether either eye develops normally. METHODS: Measurements were obtained on 237 rhesus monkeys, whose ages ranged from birth to 5 years. Examinations included cycloplegic refraction by retinoscopy, keratometry measurements, and A-scan ultrasound measurements of axial length. The time course of development was evaluated using a growth curve analysis appropriate for a mixture of cross-sectional and longitudinal data. RESULTS: At birth, all three parameters were normally distributed and only weakly correlated. Monkeys had +7 D (SD=2.3 D) of hyperopia, corneal power of 58 D (SD=1 D), and axial length of 13.2 mm (SD=0.4 mm). Refractive error ranged from +0.5 D to +14.5 D, with a mean difference between the two eyes of 0.5 D. Corneal curvature ranged from 61 D to 54 D, with a mean difference between the two eyes of 0.8 D. Axial length ranged from 12.0 mm to 14.2 mm, with a mean difference between the two eyes of 0.1 mm. Although the degree of hyperopia achieved asymptote, of + 2 D, shortly after 1 year of age, corneal curvature and axial length did not achieve asymptote until nearly 5 years of age. By this time, refractive error had declined by 5 D, corneal curvature had declined by 7 D, and axial length had increased by 6 mm. CONCLUSIONS: The magnitude of the individual differences that can occur in a small sample of experimental subjects is large enough to necessitate reference to age norms derived from a large population. Our results provide a baseline for studies of normal and abnormal eye growth and ametropia in primates. Our results also led to the confirmation of a set of "rules" that have been offered as an explanation of how these three parameters interact during emmetropization.

Aging↗
PubMed1998

[Evaluating the patient satisfaction questionnaire after inpatient treatment in phoniatrics and pediatric audiology--a contribution to quality control?].

PURPOSE: In Germany public hospitals are compelled to evaluate patient satisfaction with their treatment as a part of quality management. The purpose of this study was to assess by means of a short questionnaire inpatient satisfaction with medical care in a phoniatric-paedaudiologic department. MATERIALS AND METHODS: From April 1995 until March 1997, 638 patients underwent inpatient treatment for phoniatric or paedaudiologic diseases in our department. A confidential questionnaire was handed out to the patients or to accompanying parents. 13 questions covered different aspects of hospital treatment, such as satisfaction with diagnostic and therapeutic measures, nursing care, accommodation, catering and administration. The participants were asked to rate on a scale of 1 (very good) to 6 (very poor). RESULTS: 306 (48%) of the patients returned their questionnaires. 16% of them expressed substantial dissatisfaction both with administration and accommodation. Only 2.7% of the patients conveyed a poor overall impression of their inpatient treatment. 3% asserted they would not want to be treated in the department again as the inpatient. However, the mean overall assessment indicated a high degree of patient satisfaction. CONCLUSIONS: Although the self-explaining 13-item questionnaire is easy to evaluate at low cost, it appears to be an inadequate measuring device for routine assessment of inpatient satisfaction since only 48% of the questionnaires could be analysed.

Adolescent↗
PubMed1998

Phonation onset: vocal fold modeling and high-speed glottography.

Phonation onset is discussed in the framework of dynamical systems as a Hopf bifurcation, i.e., as a transition from damped to sustained vocal fold oscillations due to changes of parameters defining the underlying laryngeal configuration (e.g., adduction, subglottal pressure, muscular activity). An analytic envelope curve of the oscillation onset is deduced by analyzing the Hopf bifurcation in mathematical models of the vocal folds. It is governed by a single time constant which can be identified with the physiological parameter phonation onset time. This parameter reflects the laryngeal state prior to phonation and can be used as a quantitative classification criterion in order to assess the phonation onset in clinical diagnosis. The extraction of the phonation onset time from simulated time series using a simplified two-mass model and from digital high-speed videos is described in detail. It shows a good agreement between theory and measurement.

Electric Stimulation↗
PubMed1998

Neuropeptide Y-like immunoreactivity localizes to preganglionic axon terminals in the rhesus monkey ciliary ganglion.

PURPOSE: To characterize neuropeptide distribution in the ciliary ganglion of rhesus monkeys (Macaca mulatta). METHODS: Cryostat tissue sections of fixed rhesus monkey ciliary, pterygopalatine, superior cervical, and trigeminal ganglia were incubated with antisera to neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP), substance P (SP), vasoactive intestinal peptide (VIP), tyrosine hydroxylase (TH), and dopamine-beta-hydroxylase (DBH). Antibody binding was visualized by indirect immunofluorescence. RESULTS: NPY-like immunoreactive (LI) nerve terminals surrounded 80% of ciliary ganglion cells, but ciliary ganglion cell somata were unstained. NPY-LI cells were present in the superior cervical ganglion, in which almost all cells were TH- and DBH-LI, and in the pterygopalatine ganglion, in which almost all cells were VIP-LI. Because neither TH, DBH, nor VIP immunoreactivity was detected in nerves contacting ciliary ganglion cells, the NPY-LI input to ciliary neurons does not likely derive from the autonomic ganglia. The trigeminal ganglion, another potential source, had no NPY-LI neurons. CGRP- and SP-LI axons from the nasociliary nerve traversed the ciliary ganglion; a small number of varicose axons were distributed among ganglion cells and rarely surrounded cell somata. Most ciliary ganglion cells were TH-LI, but only a few were DBH-LI. CONCLUSIONS: Based on these patterns of peptide immunoreactivities, the NPY-LI nerve fibers investing ciliary ganglion cells in the rhesus monkey are most likely preganglionic axon terminals of mesencephalic parasympathetic neurons. Although the origin and function of these NPY-LI nerves remains to be established, the present finding adds to the remarkable diversity of neuropeptide immunoreactivity so far identified in preganglionic and postganglionic cells of the ciliary ganglion in different species of birds and mammals, including primates.

Animals↗
PubMed1997

Distribution of muscarinic cholinergic receptor proteins m1 to m4 in area 17 of normal and monocularly deprived rhesus monkeys.

Antibodies to muscarinic cholinergic receptor proteins m1 to m4 were used in striate cortex tissue of normal rhesus monkeys to determine the laminar distribution of these proteins with special attention to geniculorecipient layers. The normal patterns were compared to those of monkeys whose ocular dominance system had been altered by visual deprivation. In normal monkeys, immunoreactivity of all four proteins was localized in complex laminar patterns; m1 was densest in layers 2, 3, and 6, followed by layer 5. In contrast, m2 reactivity was densest in lower layer 4C and in 4A; the latter exhibited a honeycomb pattern. Layers 2 and 3 displayed alternating dense and light regions; this pattern was complementary to that of cytochrome oxidase (CytOx). Laminar immunoreactivity for the m3 receptor was similar to the CytOx pattern, including a honeycomb in 4A and a pattern of alternating darker and lighter patches in layers 2/3. Antibody to m4 reacted most densely with layers 1, 2, 3, and 5, layers 2 and 3 exhibited alternating dark and light regions, and layer 4A had a faint honeycomb. Layer 4C was the lightest band. The differential distribution of these four muscarinic receptor subtypes suggests distinct roles in cholinergic modulation of visual processing in the primate striate cortex. Furthermore, all four muscarinic receptors appear to be insensitive to elimination of visual input via monocular occlusion from birth, to deprivation of pattern vision in one eye during a specific time period in adulthood, and to long-term retinal injury.

Animals↗
PubMed1997

Neuropeptide Y in the infundibular nucleus and hypophysis of great apes.

We studied the distribution of neuropeptide Y (NPY) immunoreactivity in the infundibular nucleus and the hypophysis of the chimpanzee, gorilla, and orangutan. Using antibodies developed in rabbit against synthetic porcine NPY, we found numerous NPY-immunoreactive neuronal somata in the infundibular nucleus; this nucleus was also filled with short NPY-positive processes and an abundance of punctate structures that could be indicative of synaptic terminals. Numerous varicose NPY-positive fibers were concentrated in the upper infundibular stem in association with capillary loops of the portal vasculature and with the long portal vessels. Bundles of long varicose fibers ran down the infundibular stem, some appearing to terminate in the lower stem in the vicinity of short portal vessels. The bulbous infundibular process contained only sparsely distributed fibers; they were mostly concentrated near vessels at the border between the infundibular process and the anterior pituitary gland, where the fibers often terminated in a spray-like fashion near blood vessels. No NPY immunoreactivity was seen in the anterior pituitary gland. These results provide anatomical evidence for the release of NPY into the portal vasculature of great apes.

Animals↗
PubMed1996

Estimation of antigen-responsive T cell frequencies in PBMC from human subjects.

A new method for estimating the frequency of antigen-responsive T cells, using a cell proliferation assay, is described. In this assay, the uptake of tritiated thymidine by peripheral blood mononuclear cells which have been exposed to antigen, is measured for each well on a microtiter plate. Whereas this assay is generally used as part of a limiting dilution assay, here we estimate the frequency of responding cells using a single, carefully chosen cell density. The traditional analysis of such data uses a cut-off to separate wells which contain no responding cells and wells which contain at least one responding cell. The new method uses the scintillation count to estimate the number of responding cells for each well on the plate. We do this by fitting a two-stage model, the first stage being a Poisson model with antigen-specific frequency parameters, and the second stage a linear model with plate-specific parameters.

Cells, Cultured↗
PubMed1996

Gap junction structures and distribution patterns of immunoreactive connexins 46 and 50 in lens regrowths of Rhesus monkeys.

Gap junction structures and distribution patterns of immunoreactive connexin46 (Cx46) and connexin50 (Cx50) in normal lenses and lens regrowths of rhesus monkeys were studied using electron microscopy and immunofluorescence double-labeling. Lens regrowths were collected from aphakic eyes of young monkeys whose natural lenses had been surgically removed 11-34 months earlier to simulate monocular congenital cataract surgery in human infants. Approximately 90% of the lens regrowths examined was in the form of a doughnut-shaped Soemmerring's ring located behind the iris. The lens regrowth consisted of lens epithelium and lens fibers enclosed within hypertrophied capsular material. The superficial equatorial region usually contained nucleated young fibers of normal appearance. The other regions consisted of many swollen fibers. Gap junctions were readily observed between fiber cells of both normal and swollen configuration in the lens regrowth. In superficial fibers, gap junctions were not associated with cytoskeletal components. In the intermediate and the deeper cortical regions, actin filament bundles were found specifically associated with gap junctions along both of their cytoplasmic surfaces. An immunofluorescence double-labeling study showed that Cx46 and Cx50 were labeled in the same gap junctions in both superficial and deeper cortical fibers of the normal lens. In contrast, in the lens regrowth strong co-labeling of Cx46 and Cx50 was only observed in the superficial fibers. The labeling for Cx50 was very weak or absent in the deeper cortex, whereas the strong labeling for Cx46 persisted throughout the major portion of the deeper cortex. The labeling for Cx46 finally disappeared in the much deeper cortex. This study shows that (1) the same distribution pattern of actin bundle/gap junction association found in normal lenses is seen in the lens regrowth, and (2) the immunoreactive distribution of Cx46 and Cx50 differ in the lens regrowths as compared with those in the normal lenses of rhesus monkeys.

Actins↗
PubMed1996

Diffuser contact lenses retard axial elongation in infant rhesus monkeys.

In each of five monkeys, one eye was fitted with a diffuser lens at birth. This lens allowed pattern vision, but also reduced contrast by about 1 log unit. In four out of five monkeys, the treated eyes were shorter and more hyperopic than the untreated fellow eyes. At 25 weeks of age, interocular differences (OD -- OS) of the experimental group were significantly greater than interocular differences of age-matched normal monkeys for both axial length (P < 0.05) and refractive error (P < 0.02). In addition, while the treated eyes were significantly different from normal eyes for both axial length measurements (P < 0.01) and refractive error (P < 0.01), there were no significant differences between the untreated fellow eyes and normal eyes. In primates less severe pattern deprivation appears to produce an effect on eye growth that is opposite to that of severe pattern deprivation (little or no pattern vision), which typically results in axial myopia.

Aging↗
PubMed1996

The enterohemolysin phenotype of bovine Shiga-like toxin-producing Escherichia coli (SLTEC) is encoded by the EHEC-hemolysin gene.

Naturally occurring enterohemolysin negative variants were observed during studies on bovine Shiga-like toxin-producing E. coli (SLTEC). Examination of three strains (413/89-1 and 332, 026:H-, and 570/89, O111:H-) and their isogenic variants (413/89-6, 332-I and 570/89-I, respectively) showed, that in each strain loss of the enterohemolytic phenotype correlated with the loss of a large plasmid ranging from 94 to 104 kb in size. The hemolysin determinant present on the 94 kb plasmid of strain 413/89-1 was cloned and discovered by DNA and N-terminal aminoacid sequence analysis to be highly homologous to the recently published EHEC-hemolysin (HlyEHEC; Schmidt et al., 1994; 1995). When a recombinant plasmid harboring this determinant was reintroduced into the enterohemolysin negative isogenic mutant 413/89-6, the enterohemolytic phenotype was restored. Southern blot hybridization analysis was used to demonstrate that the HlyEHEC is plasmid-borne in SLTEC-strains. Our cumulative data suggest that the enterohemolytic phenotype of SLTEC is encoded by the plasmid-borne HlyEHEC. These results further demonstrate the close similarity between SLTEC-isolates from bovine and human.

Animals↗
PubMed1996

[Early indications for surgical vocal cord medial relocation in unilateral recurrent nerve paralysis in advanced age].

BACKGROUND: Unilateral vocal cord paralysis is usually treated conservatively. Phonosurgery is not indicated before 1 year after the onset of the palsy as during this period spontaneous recovery can be expected. In the elderly patient conservative voice rehabilitation is often limited by a restricted general condition. In these cases a severe communication disorder may result unless vocal cord function recovers spontaneously. PATIENTS AND METHODS: In 4 patients aged 68 to 79 years who had suffered from latrogenic unilateral vocal cord paralysis for 6 to 9 months, surgical medialisation of the paralysed vocal cord was carried out in local anaesthesia as an Isshiki-Type-I-operation after unsuccessful conservative treatment prior to surgery. RESULTS: In all cases a definite amelioration of voice function could be reached. There were no local or general complications. No spontaneous recovery of nerve function could be detected by electromyography between 6 to 9 months after the operation. Voice function remained stable during this period. CONCLUSIONS: We conclude that in elderly patients with unilateral vocal cord paralysis with no signs of spontaneous recovery and unsuccessful conservative treatment, surgical voice rehabilitation may be indicated before 1 year after the onset of the palsy.

Aged↗
PubMed1996

[Speech-specific cortical potentials--methodologic aspects and initial clinical results].

BACKGROUND: The purpose of this study was to find out whether specific cortical potentials can be evoked and identified after word stimulation. The clinical relevance was to be investigated in patients with aphasic syndromes. MATERIALS AND METHODS: In 20 young adults with no signs of hearing impairment and in patients with manifest aphasic syndromes, word-evoked cortical potentials were compared with those after an equivalent noise stimulus. The test words were selected from the Freiburger Speech Comprehension Test. The duration of the words was between 450 and 640 ms. The stimulus was presented monaurally. The peak level was 70 dB HL. The noise stimulus was produced by modifying a low-band noise. Potentials were measured between the ipsilateral mastoid and the contralateral forehead. Data were analysed offline. RESULTS: In healthy persons, the potentials after word and noise stimulation did not differ until 100 ms after the stimulus onset. After noise stimulation a negative maximum could be seen 100 ms after the stimulus onset, and a positive maximum 200 ms after the stimulus onset. After word stimulation, a positive maximum of higher amplitude than after noise stimulation was measured 150 ms after the stimulus onset, and a negative maximum was measured 270 ms after the stimulus onset. In all test persons the difference curve of word-and noise-evoked potentials revealed a speech-specific component 170 ms (N 170) after the stimulus onset. The single-word analysis showed that the potentials depend on the phonemes of the test word. The potentials do not alter when the stimulus side is changed. In patients with aphasia the potentials depend on the grade of the disturbance of speech perception: global and Wernicke's aphasia show no significant difference of speech-and noise-evoked potentials, whereas in Broca's aphasia a speech specific maximum is apparent. CONCLUSION: The speech-specific component may be regarded as a paradigm of cortical speech detection processes. Electrophysiological speech audiometry by means of word-evoked cortical potentials seems possible and may be used for clinical purposes.

Adult↗