Search PubMed⌕ Search

Biomedical subjects

R Hauser

Publications and source records attributed to R Hauser.

At least 109 records · Page 6Linked to original sources
PubMed1994

Retrograde ejaculation.

Retrograde ejaculation is an uncommon cause of male infertility. It should be suspected in any case of azoospermia, and might be congenital, acquired or idiopathic in origin. When pharmacological attempts to restore anterograde ejaculation fail, it is suggested that spermatozoa should be recovered from post-ejaculation urine to be applied in one of the modern techniques of assisted reproduction. The successful recovery of viable spermatozoa from the urine is dependent upon careful regulation of pH and osmolarity of the urine at the time of ejaculation. Careful handling of the retrieved spermatozoa enables isolation of sperm cells with good quality for insemination of ovulated oocytes (in vivo) or retrieved oocytes (in vitro).

Ejaculation↗
PubMed1994

Management of bilateral nonpalpable testes: laparoscopic diagnosis and orchidectomy.

Bilateral nonpalpable testes in the adult human are associated with testicular malignancy, infertility and other abnormalities. Investigation for localization of the testes is mandatory, and either orchidopexy or orchidectomy is indicated. Laparoscopy was performed in an azoospermic male with bilateral unpalpable testes. A diagnosis of intra-abdominal testes was made and bilateral orchidectomy was performed. Laparoscopy is recommended for diagnosis and precise localization, as well as for orchidectomy, thus avoiding open abdominal operation in cases of intra-abdominal testes.

Adult↗
PubMed1994

Dependence of distortion product emission amplitude on primary-tone stimulus levels during middle-ear pressure changes.

The measurement of distortion product otoacoustic emissions (DPOAEs) is dependent upon their transmission through the middle ear. The purpose of this study was to measure the combined effects of primary-tone level variation and of middle-ear pressure alterations on DPOAE amplitudes. Twenty ears of normally hearing adults were examined. Four DPOAEs were measured at the frequency 2f1-f2 (614 Hz, 1342 Hz, 2921 Hz, 6341 Hz), with the associated geometric mean (GM) of the primary tones at 1, 2, 4, and 8 kHz. Ambient air pressure was varied in a pressure chamber between 0 kPa and 6 kPa in 2-kPa steps. At each pressure level, L1 or L2 was varied in 5-dB steps between 40 and 60 dB HL with a corresponding fixed level of either L1 or L2 of 40 dB HL. The DPOAE amplitudes showed frequency-dependent changes. The largest mean amplitude reduction with pressure variations could be observed for the DPOAE at 614 Hz, whereas the DPOAEs at 6341 Hz remained practically unaffected. During variation of primary-tone levels, the maximum DPOAE amplitude generally occurred, independent of middle-ear pressure, when L1 was 5 to 15 dB greater L2. The results have implications for clinical measurements in that DPOAEs may be detected in the high-frequency range even under pathologically altered middle-ear pressure, and the optimum difference L1-L2 that produces maximum DPOAE amplitude is relatively unaffected by middle-ear pressure.

Acoustic Stimulation↗
PubMed1994

The Balgrist hip socket for cementless fixation in primary total hip replacements and in acetabular revisions.

The results of 532 hip arthroplasties in which an uncemented Balgrist hip socket had been used in 387 primary total hip replacements and in 145 acetabular revisions were reviewed after a maximum of six years. The socket consists of two tapered parts, namely an expansive outer titanium-alloy split ring and an insert of polyethylene. The mean age of the patients at the time of operation was 54.3 years in primary hip replacements, and 64.7 years in acetabular revisions. Acetabular deficiency according to the AAOS classification was found in 21% of the primary arthroplasties, and in 80.7% of the acetabular revisions. Using Kaplan-Meier survivorship analysis, with the use of prosthesis revision as the endpoint of failure, the survival rate at five years was 99% in primary arthroplasties, and 88.7% in acetabular revisions. Our data suggest that the unique socket design of the Balgrist hip socket gives very satisfactory clinical results not only in primary hip replacements but also in acetabular revisions even with various acetabular defects.

Adolescent↗
PubMed1993

Effects of atmospheric pressure variation on spontaneous, transiently evoked, and distortion product otoacoustic emissions in normal human ears.

The effects of atmospheric pressure changes on the frequency and amplitude of spontaneous (SOAEs), transiently evoked (TEOAEs) and distortion product (DPOAEs) otoacoustic emissions in normally hearing humans were compared. The purpose was to determine if the transmission of each form of OAE was influenced differently by the middle ear. Sixty-one subjects were tested in a pressure chamber. Twenty-seven SOAEs with a frequency range between 535 to 4729 Hz from 21 subjects were examined. Transiently evoked OAEs were studied in 20 subjects using clicks and tone-bursts at 0.5, 1, 2, 3, and 4 kHz. Distortion-product OAEs were generated at seven geometric mean frequencies between 1 and 8 kHz in another 20 subjects. Spontaneous OAEs were examined by applying atmospheric pressure up to 9 kPa and down to -2.5 kPa, for the measurement of TEOAEs and DPOAEs the pressure was varied from 0 kPa up to 8 kPa. In spite of large interindividual differences, results suggest that the influence of pressure on the three OAEs is frequency specific. The frequency and amplitude change of SOAEs, the modification of the amplitude and spectra of TEOAEs, and the amplitude change of DPOAEs are more influenced by changes in middle ear pressure below 4 kHz than are OAEs in the range at 4 kHz and above.

Acoustic Stimulation↗
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

Isolation of dnaJ, dnaK, and grpE homologues from Borrelia burgdorferi and complementation of Escherichia coli mutants.

The heat-shock proteins DnaJ, DnaK, and GrpE are involved in the replication of various species of DNA in Escherichia coli, in addition to their roles in other processes, including protein disaggregation and export. We have cloned the Borrelia burgdorferi homologues of these genes. DNA sequence analysis revealed an open reading frame encoding a protein that is 62% identical to the E. coli DnaK protein. Genes homologous to the E. coli grpE and dnaJ genes, encoding products 28% and 39% identical to their homologues, are located up- and downstream, respectively, of the B. burgdorferi dnaK gene. No obvious promoters were detected in the sequenced DNA, although a potential transcription terminator was found downstream of the dnaJ gene, so these three genes may form an operon, perhaps with a fourth gene located upstream of the grpE gene. The grpE homologue complemented an E. coli grpE mutant and the dnaJ homologue complemented an E. coli dnaJ mutant, whereas the B. burgdorferi dnaK gene did not complement dnaK mutants.

Amino Acid Sequence↗
PubMed1993

The self-locking Balgrist hip socket for cementless fixation: biomechanical principles and clinical results.

The Balgrist hip socket, initially made entirely of HDPE (high molecular weight polyethylene), now made of outer titanium alloy shell that faces the bone of the acetabulum has been in clinical use for 10 years. The purpose of this presentation is to illustrate the biomechanical principles that have governed this unique design and to present the clinical results that we have obtained until the end of 1991 with 717 implants. From 1982 to 1987 Balgrist HDPE sockets had been implanted for 346 hips, from 1984 to 1991 Balgrist Titanium alloy sockets have been implanted for 371 hips. The number of revision are 55 of 717 hips. 48 hips out of 55 were with Balgrist HDPE sockets. On the contrary, only 7 hips were with Balgrist titanium socket. The greatest benefit of Balgrist Titanium socket is the excellent mechanical lock with subchondral bone of the acetabulum.

Biomechanical Phenomena↗
PubMed1993

Monitoring the effects of noise exposure using transiently evoked otoacoustic emissions.

One possible alternative to conventional pure-tone testing for screening and monitoring cochlear changes is the measurement of otoacoustic emissions. The aims of this study were to determine the feasibility of using transiently evoked otoacoustic emission (TEOAE) measurements as an objective field procedure and to compare the sensitivity of the measurements indirectly to pure-tone thresholds. The test groups were 117 male recruits and 30 male career cadets in compulsory military service in Switzerland. Transiently evoked otoacoustic emissions were measured before and at the end of a 17-week training period that included exposure to noise from firearms. Results revealed significant changes in response amplitudes in the frequency range from 2 to 4 kHz, whereas changes in the frequency range from 0.5 to 2 kHz were not significant for either group. The changes in relative amplitude did not exceed 15% when spectra containing the lower frequencies were considered. However, they were always greater than 83% within the higher-frequency range. All mean changes were in the direction expected from cochlear damage. Comparison of TEOAE results with pure-tone thresholds measured for a similar sample of subjects indicated that TEOAE testing may be more sensitive than pure-tone audiometry in detecting early cochlear damage from noise. The testing of TEOAEs is feasible as a screening procedure. It offers objective and repeatable information and is substantially less time consuming than pure-tone audiometry.

Adult↗
PubMed1993

Clinical monitoring using otoacoustic emissions.

Damaging influences to the cochlea are a leading cause of sensorineural hearing loss. Examples include acute or chronic noise exposure and cochleotoxic drugs such as aminoglycosides. Typically, once damage has occurred, the cochlea cannot recover. Therefore, prevention is critical. If damaging influences cannot be avoided, then secondary prevention or early detection of cochlear hearing loss becomes important. Ideally, methods for the detection of cochlear damage should be as specific and as sensitive as possible. Otoacoustic emissions satisfy these criteria and offer a means of testing aspects of cochlear function in a non-invasive and objective way. Evoked otoacoustic emissions measured either after transient stimuli or during two-tone stimulation (distortion-product otoacoustic emissions) are the types most commonly used for clinical purposes. They are stable over time within individual ears and their repeatability has been established under conditions of clinical testing using commercial equipment. Thus, they are well suited as an effective means of monitoring subtle changes in cochlear status. The possibility of making non-invasive repeated measures of cochlear function has led to the widespread use of otoacoustic emissions in animal experiments. Influences of development, anoxia, anaesthesia, noise, and drugs have been monitored. Preliminary studies in humans demonstrate that cochlear damage due to ototoxic drugs such as aminoglycosides or cisplatin and due to noise exposure can be detected using otoacoustic emissions. Comparison of such results to those available using pure-tone audiometry indicates a greater sensitivity of otoacoustic emissions for detecting early cochlear damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗
PubMed1993

[New methods for predicting sperm fertilizing ability].

There is no reliable method for screening for the fertilizing ability of sperm. 3 new methods are presented: the freezing test (FT), hypoosmotic swelling test (HOST) and migration-sedimentation test (MST). The first 2, test the functional integrity and stability of the sperm membrane under certain osmotic conditions. The MST determines ability to separate high quality sperm. All tests were performed using either fresh semen of husbands, or thawed semen of donors used for fertilization in the IVF unit. Results of the FT were not correlated with the fertilizing ability of sperm in IVF, but HOST results with fresh, but not thawed semen, were correlated. Fertilization of oocytes in IVF was significantly better when HOST value of fresh semen was 45% or more. Motility and morphological normality of sperm separated by MST were better in ejaculates that fertilized ova under in vitro conditions, than in those that did not. Sperm separation by MST of 25% or more of motile sperm, or of more than 1.5 million motile sperm in the sample, indicated statistically significant ability for oocyte fertilization in an IVF system.

Cell Membrane↗
PubMed1993

[Presbycusis].

Hearing loss in the elderly is the most common type of hearing impairment. The term presbyacusis has been used to describe this category of hearing loss when there are no other etiological factors. However, the term is not precise, because any of several locations along the auditory pathway may be involved to produce the symptoms. The diagnosis is based more on the course of the hearing loss and the associated biological signs of aging than on specific criteria. The loss of speech-understanding ability is one of the most important indicators for a therapeutic intervention, which generally aims at amplification using a personal hearing aid. An improvement in speech-understanding ability with a hearing aid depends on several complex factors, and there is a large amount of intersubject variability in the benefit derived from amplification, even when the magnitude of the hearing loss is comparable. The aim of research on presbyacusis over the next several years--keeping in mind the demographic development in the industrialized countries--will be to further the differential analysis of the factors contributing to auditory communication disorders in the aging population.

Aged↗
PubMed1992

Postpartum periarticular hip abscess with later coxitis caused by group B streptococcus.

Intrapartum haematogenous spread of vaginal group B Streptococcus is rare, but it can lead to severe complications like abscesses, endocarditis and meningitis postpartum. We report a postpartum periarticular hip abscess caused by group B Streptococcus. Clinically it caused pain in the hip and a compression of the femoral nerve with motor and sensory component. Diagnosis was made by aspiration under computed tomography control. The only sign of infection was an increased sedimentation rate. After antibiotic treatment the symptoms disappeared and the abscess vanished, but it was reactivated 4 months after delivery, leading to arthritis of the hip joint. Another antibiotic treatment was administered for 8 weeks. 17 months postpartum the patient is well, but a development of a secondary coxarthrosis can not be excluded.

Abscess↗