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Biomedical subjects

M Giesen

Publications and source records attributed to M Giesen.

At least 19 recordsLinked to original sources
PubMed1993

[Cutaneous condylomata acuminata of an unusual site and extent. Successful CO2 laser therapy].

We report on a 33-year-old patient with unusually extensive and predominantly cutaneous condylomata acuminata spreading from the penis over the mons pubis to the entire lower abdominal wall but almost completely sparing the genital mucous membranes. Single lesions were found on the left arm and on the buttocks. Southern blot hybridization detected HPV-6a DNA sequences within the fibroepithelial tumours. Carbon dioxide laser treatment resulted is cosmetically acceptable healing without recurrence.

Abdominal Neoplasms↗
PubMed1990

Papillomavirus common antigen in Bowen's disease.

We studied 173 biopsies of histologically determined Bowen's disease and looked for the presence of papillomavirus antigen using immunoperoxidase staining. Fifty-nine of the lesions were located at the head, 49 at the extremities, 36 at the trunk and 29 originated from the genital region. Papillomavirus capsid antigen could be clearly identified in 39 (22.5%) cases. Eleven (38%) of the 29 lesions located on genital skin were positive for papillomavirus capsid antigen while 28 (19.4%) of the 144 biopsies from other skin regions contained viral antigen. Our findings are suggestive of an etiologic relationship between the virus and this dermatosis which represents a special variant of squamous cell carcinoma. They indicate that human papillomaviruses may play an important role in the development of cutaneous malignancies.

Adolescent↗
PubMed1988

Phenotypic selection on the dentition in a Late Archaic population of Ohio.

Significant phenotypic selection acting on the buccolingual diameters of the permanent first and second molars is established for a Late Archaic population in Ohio. Directional selection appears to be acting on an index that increases the size of the maxillary first (UM1) and mandibular second (LM2) molars and decreases the size of the maxillary second (UM2) and mandibular first (LM1) molars. Variance selection is fundamentally disruptive but results in a more integrated (highly correlated) set of characteristics in the after-selection sample.

Adolescent↗
PubMed1981

[Medium-latency acoustically evoked brain potentials used for examination of the auditory pathway (author's transl)].

Potentials of the 10-15 ms latency range evoked by acoustic clicks and Gauss-shaped tone bursts habe been investigated in normal hearing adults, 20 patients with cochlear damages, and 6 cases of temporal lobe processes. Methods and results are compared to those of brain stem audiometry. Mean and standard latency ranges are calculated for the different peaks (Fig. 1). Amplitudes should be used only for side difference evaluation in the same patient, because of their big interindividual variation. In cases of profound high frequency hearing loss (Fig. 2) medium-latency potentials yield true threshold values in the low frequency range, where brainstem potentials are failing. The medium latency potentials show a substantial decrease of amplitude for stimuli contralateral to the damaged side (Fig. 3). So this method can be a functional hearing test to detect or at least suspect temporal damages.

Audiometry↗
PubMed1979

Chronic and acute transtentorial herniation with tumours of the posterior cranial fossa.

In patients with expanding lesions of the posterior fossa general hyper-reflexia (and bilateral latency shifts of auditory evoked brain stem potentials) have been noted as possible symptoms of chronic ascending transtentorial herniation. After ventricular tap, this chronic herniation may evolve into acute herniation with progressive reduction of consciousness which in our experience can only be survived by decompression of the compressed brain stem. The chronic transtentorial herniation is related morphologically to demyelination of the pyramidal tracts and the auditory pathways, whereas the acute transtentorial herniation is related to microcirculatory disturbances in the reticular formation of the mesencephalo-pontine junction.

Auditory Pathways↗
PubMed1979

[Objective diagnosis of recruitment by brainstem audiometry (author's transl)].

The differential diagnosis in cochlear damage with brainstem potentials is easily done by looking for normal latencies that coincide with substantial hearing loss. Further validation can now be achieved with methods representing Fowler and SISI test equivalents. Amplitudes of brainstem potential were compared in 28 patients with marked differences of hearing loss in either ear. Amplitudes are balanced at the stimulus intensity corresponding to subjective loudness balance (Fig. 3). Intersubject comparison of input/output function steepness is not advisable because of the greater interindividual variation of amplitudes (Fig. 2). Amplitude modulation by short Gauss-shaped increments (Fig. 1) or by decrements of a continuous tone evokes clear brainstem potentials at thresholds of about 5dB above subjective detection, but it also depends upon stimulus duration or steepness (Fib. 4), frequency (Fig. 5) and the degree of modulation (Fig. 6). With a cochlear hearing loss of more than 40dB, a 1 dB increment evokes potentials for continuous tone intensities higher than 20 dB above subjective thresholds (Fig. 7). This test is mainly useful for children with retarded language development and lacking a stapedius reflex, for adults, who cannot sufficiently cooperate, and where there is a prolonged latency due to middle ear damage or a steep high frequency loss.

Audiometry↗
PubMed1979

[The complex tympanic membrane impedance in various middle ear disturbances (author's transl)].

Clinical experience with two-component registration (Susceptance and Conductance) of the tympanic membrane impedance at two frequencies (220 and 660 Hz) is reported. More than 1000 results of the last 6 years have been evaluated. The normal tympanometric shape is confirmed by computer simulation. More information about mass and elasticity relations of the middle ear is obtained by the complex registration at 660 Hz. Clinical examples are presented to demonstrate the influence of scars on the ear drum and of a disruption of the ossicular chain. In 77 cases of otosclerosis with stapes fixation, as confirmed by operation, the shape of the pressure-dependent admittance is significantly narrower than in normal hearing ears. For a glomus tumor a pulsation of the oto-admittance following the electro-cardiogram can be shown. In a classification of the tympanometric types the different shapes correspond well to the set of functional finding (normal) ears, otosclerosis, Eustachian tube malfunction, processes of the middle ear cavity, post operation state). The extreme sensitivity of the method, however, produces a small group of unpredictable results for each type. So differential diagnosis is to be done by usual audiometric methods or microscopy of the ear drum.

Acoustic Impedance Tests↗
PubMed1978

[Quantitative results of the brainstem audiometry in middle ear, cochlear, and retrocochlear hearing damage (author's transl)].

After a discussion of the technique and validity of the objective audiometry using acoustically evoked brainstem potentials, we demonstrate the shape of potentials at various locations of the scalp. We compare the objective findings for middle and inner ear hearing losses with the subjective audiogram. Disturbances in the middle ear are marked through a letency shift corresponding to the hearing loss with normal bone conducted reaction. When the cochlea is damaged we notice a quick decrease in amplitude from the loudnesscompensation to the threshold with normal latencies. As examples for retro-cochlear damages we give the cases of a child, retarded after encephalitis, of an infant and of a patient with stato-acoustic neurinoma, whereby also the cochlear, subcortical and cortical potentials are evaluated.

Acoustic Stimulation↗
PubMed1978

[Ventilation measurings before, during and after treatment of tracheal stenosis due to long term intubation (author's transl)].

17 patients with post-intubation stenosis of the trachea were studied. By the extrathoracic stenosis the relative forced expiratory volume in the first second (FEV1,0) and in and expiratory flow were decreased, total airway resistance (Rt) was increased. After implantation of an endoprothesis the obstruction was significantly lowered (p less than 0,05). After removal of the tracheal endoprothesis further improvement occurred as was demonstrated by an increase in FEV1,0 an flow and by a decrease in Rt.

Adolescent↗
PubMed1978

[Early and late functional hearing results from a modified technique for tympanoplasty (author's transl)].

This paper is a comparative study of the early and late functional results of tympanoplastic operations, as modified by Khan. Following such surgery, we examined 494 patients who had been operated on between 1970--1972 in the ENT Clinic of the Free University of Berlin (Klinikum Westend). Preliminary and final hearing results were recorded with the aid of sound audiograms, which were critically assessed by two different types of evaluations. These included the results of pure-tone changes and speech reception thresholds as achieved by the tympanoplastic operations. On the basis of socially useful hearing improvements, the functional results of cases operated in our clinic are above average. The hearing gain shown from post-operative controls to the final studies is especially satisfactory, since this also includes an improvement in bone conduction.

Acoustic Impedance Tests↗
PubMed1977

[Damages of the auditory pathway at brain stem level investigated by acoustically evoked potentials (author's transl)].

In 57 patients with operated expansive tumors in the postcranial fossa auditory evoked brain stem potentials were investigated. A group of 36 with neurological evidence for the brain stem compression showed significantly prolonged latencies (Fig. 1), whereas the evoked potentials were nearly normal in the preceding state of CSF circulatory disturbances (21 cases). For one patient with a neurinoma of the right trigeminal root the post-operative reduction of the pathological latency shift is demonstrated (Fig. 2). Latency evaluation of evoked brain stem potentials are used in our clinical routine for differential diagnosis of retrocochlear hearing damages.

Acoustic Stimulation↗