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Biomedical subjects

C Ulrich

Publications and source records attributed to C Ulrich.

At least 73 records · Page 4Linked to original sources
PubMed1995

Enterococcus faecalis colonisation and endocarditis in five intensive care patients as late sequelae of selective decontamination.

OBJECTIVE: To describe Enterococcus faecalis colonisation and endocarditis in 5 intensive care patients after treatment with selective decontamination (SDD). SETTING: Intensive care unit (ICU) in a general hospital. PATIENTS: The patients were admitted to the ICU because of adult respiratory distress syndrome, polytrauma (2 patients), abdominal aortic surgery and gastrointestinal surgery. Because these patients needed mechanical ventilation they received systemic cefotaxime and SDD (polymyxin E, amphotericin B and norfloxacin). RESULTS: Colonisation with E. faecalis was documented in all patients. Intravascular catheter-related infection with E. faecalis occurred in 4 patients. None of the patients received antibiotics active against, E. faecalis, because body temperature normalised after catheter removal. In the course of his ICU stay one patient died. Autopsy showed E. faecalis endocarditis. The other 4 patients recovered from their primary illness, but had to be readmitted after several months because of E. faecalis endocarditis. One of these patients died. One patient recovered of endocarditis, but one year later valve surgery was necessary. The other 2 patients needed acute valve replacement. The latter 3 patients survived. CONCLUSION: We observed 5 patients with E. faecalis endocarditis as a late and severe sequela of SDD during their ICU stay.

Aged↗
PubMed1995

[Value of venting drilling for reduction of bone marrow spilling in cemented hip endoprosthesis].

A rise in intrafemoral pressure during the implantation of a cemented hip replacement seems to have been proven in experimental and clinical studies. The biological system of the femur equalizes this pressure by means of its venous drainage system, which is located at the linea aspera and distal metaphysis. The intravasation of bone marrow, fat and debris that follows leads to characteristic clinical signs of a more or less distinct embolism of the lung, which is indicated by an intraoperative drop in blood pressure and end expiratory pCO2. The logical therapeutic measure to avoid biological self-drainage of the femur is to create sufficient extrafemoral drainage via a unicortical venting hole distal from the expected tip of the prosthesis, which must be combined with an intramedullary plug to preserve the desired effect of the high-pressure technique for cement-bone interlocking. If it is also possible to install a vacuum in the medullar cavity of the femur to draw the cement into the cancelleous bone, an optimal cementing result in combination with minimal patient risk can be promised.

Bone Cements↗
PubMed1994

Influence of suction cup oculopression on corneal astigmatism.

In 11 (right) eyes of 11 ocularly healthy subjects an artificial stepwise intraocular pressure (IOP) elevation was applied by suction cup oculopression. The initial negative pressure in the suction cup was 80 mmHg; it was raised in steps of 40 mmHg. The median of the corneal astigmatism, measured with a Zeiss ophthalmometer, was 0.50 D before oculopression (the values of the 10th and 90th percentiles were 0.30 and 1.10 D, respectively). Corneal astigmatism increased to 2.00 (0.00-5.10) D, 2.25 (1.00-5.55) D, 2.63 (0.63-7.00) D, 3.38 (1.88-6.88) D, 3.38 (2.83-7.25) D, and 4.38 (2.85-5.63) D with 80, 120, 160, 200, 240, and 280 mmHg oculopression, respectively. The astigmatism dropped to 0.75 (0.00-2.30) D immediately after removal of the suction cup. Thus, suction cup oculopression not only influenced IOP but also ocular refraction. This is of particular importance since visual evoked potential (VEP) amplitude is to a high degree dependent on refractive changes. This fact has to be considered if changes in VEP amplitude during suction cup oculopression are used as a tolerance test in glaucoma diagnosis.

Adult↗
PubMed1994

[Effect of change in refraction by increasing intraocular pressure with the suction cup method on pattern reversal VECP].

When IOP is increased by the suction cup method, refraction changes will occur, depending on the shape of the cup and the height of the IOP increase. Similar refraction changes were simulated in six healthy volunteers by employing spherical and cylindrical glasses during pattern-reversal visual evoked cortical potential (VECP) with various check sizes and amount of contrast. While the pattern-reversal VECP latencies were not influenced, the amplitudes were reduced considerably. By using contact lenses and a suitably shaped suction cup, refraction changes could be compensated for. In 22 healthy volunteers pattern-reversal VECPs were derived with and without the application of contact lenses with artificially raised IOP. A comparison showed that the amplitudes differed significantly. Without contact lenses a negative pressure of more than 40 mmHg resulted in a drop in the amplitudes with a plateau formed between 80 and 120 mmHg. With compensation by contact lenses the amplitudes are found to be unaltered or even slightly increased until a negative pressure of 120 mmHg is reached in the suction cup, after which they drop. Plotting the pattern-reversal VECP amplitudes (obtained with refraction changes being compensated for by contact lenses) against ciliary perfusion pressure, one finds the characteristic curve described by Ulrich et al., suggesting an autoregulative capacity between 15 and 20 mmHg in healthy persons. The latencies, which remain uninfluenced by refraction changes, are also not altered within an IOP increase of 15-20 mmHg.

Adult↗
PubMed1993

Characterization and sequence analysis of a small cryptic plasmid from Lactobacillus curvatus LTH683 and its use for construction of new Lactobacillus cloning vectors.

Lactobacillus curvatus LTH683, a strain originally isolated from raw sausage, contains the single cryptic plasmid called pLC2. The sequence and genetic organization of the complete 2489-bp plasmid pLC2 was determined and used as the basis for construction of a series of vectors useful in Lactobacillus strains. The major parts of pLC2 nucleotide sequence could be aligned with other plasmids from gram-positive bacteria replicating by a rolling circle mechanism of replication (RCR). Direct evidence for a RCR mechanism was obtained by showing the accumulation of single-stranded plasmid intermediates in the presence of rifampicin. Three protein-coding sequences could be predicted and the corresponding proteins were detected after in vitro transcription/translation of pLC2 plasmid DNA. ORFs 1 and 3 showed minor homologies to plasmids of gram-positive bacteria. The replication protein coded by ORF2 and its corresponding target sequence, the plus origin, were similar to replication regions of other gram-positive bacteria plasmids like pLS1, pWV01, and pE194. Upstream of the ori+ site, in a noncoding region, which was nonessential for replication, strong homology to other Lactobacillus plasmids like pC30i1, pLP1, pLJ1, and pLAB1000 could be detected. A palindromic sequence predicted to be the minus origin of replication was localized there. Small vectors (3213 bp) suitable for cloning in lactobacilli were constructed based on a 1635-bp DNA fragment of pLC2, containing the region necessary for replication, marked with the chloramphenicol resistance gene and a multiple cloning site.

Amino Acid Sequence↗
PubMed1993

Three-dimensional CT of the middle ear and adjacent structures.

Three-dimensional (3D) computed tomography of the middle ear and adjacent structures has been carried out in two cadaveric heads from axial and coronal high-resolution images. The structures shown on the images of the walls of the tympanic cavity are illustrated. The usefulness and limitations of the technique, in this region, are discussed: use of grey level volumes at the surface of the slices and the inclusion of structural landmarks is emphasized. The 3D representations show the anatomical spacial relationships of the small structures in and around the middle ear to advantage. The information may be of use in surgical orientation.

Cochlea↗
PubMed1993

Staff distress among haemophilia nurses.

To investigate the severity, sources, and means used to cope with the distress experienced by haemophilia nurses as a result of the widespread infection with Human Immunodeficiency Virus among haemophiliacs, we collected anonymous questionnaire data from all nurses in the Haemophilia Nursing Network Directory, compiled by the National Haemophilia Foundation in June, 1990. Questionnaires were returned by 136 of the 181 (75%) nurses in the sample. Over 50% of the sample gave distress responses to 15 of 44 statements. Areas associated with the greatest distress were: (1) Failure of patients to take steps to prevent transmission of HIV; (2) Fear of getting infected, and (3) the repeated loss experienced as patients died from infection. Nurses working with haemophiliacs for 11-15 years were particularly vulnerable to feelings of guilt for having participated in the treatment that resulted in HIV infection. Fear of contagion and distress from patient deaths were mutually exclusive ways of reacting to HIV in haemophiliacs. Looking for a new job was related to all major sources of distress. Interaction with peers was perceived as being the most useful source of emotional support.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Osteogenesis imperfecta: clinical symptoms and update findings in computed tomography and tympano-cochlear scintigraphy.

Osteogenesis imperfecta (OI) is an autosomal-dominantly inherited connective tissue disorder characterized by abnormal bone fragility combined with blue sclerae. The association of OI with hearing impairment is commonly known as Van der Hoeve-de Kleyn syndrome. Besides typical symptoms we here report on findings by high resolution CT and by high resolving scintigraphy of the labyrinthine capsule in 3 families (9 patients) with OI, which resemble those in otosclerosis (OS): In 4 of 6 cases with OI and mixed hearing loss, severely decreased peri-cochlear bone density was established by CT. In these cases, increased bone metabolism could be revealed by high resolving tympano-cochlear scintigraphy (TCS) in the cochlear region. In 2 patients with mixed hearing loss and 3 cases without hearing impairment or with slight conductive hearing loss, bone alteration was not detectable by CT and TCS. These results raise the question whether OI and OS lead to similar labyrinthine bone alterations, based on different aetiologies or whether these diseases may co-exist, OS being part of OI.

Adolescent↗
PubMed1993

[Eye-pressure tonometry in prevention of glaucoma].

Oculo-pression tonometry (OPT) was introduced in 1984 as a clinical method of examining ocular hydrodynamics. The method involves measuring intraocular pressure (IOP) by applanation tonometry performed before, during and after application of a pressure load that disturbs the dynamic balance between aqueous production and aqueous outflow. From the IOP before (P0) and immediately after (Pr0) the 8-min pressure load period, the outflow facility C(u) can be calculated: [formula: see text] The examinations performed so far have shown that (1) reduced outflow facility can be detected by OPT with a high degree of reliability, and (2) reduced outflow facility is always preceded by the development of glaucoma damage to the optic nerve head. A prospective study has shown that in the group of patients with reduced outflow facility but without glaucoma damage, 73% developed glaucoma damage with typical changes of the papilla and visual field within 3-7 years after the first examination.

Equipment Design↗
PubMed1993

[Disordered peripapillary microcirculation in glaucoma patients].

To study the haemodynamics of the peripapillary choroid, perfusion pressure videoangiography (PVA) was performed in six healthy subjects and in seven patients with primary open-angle glaucoma (poag). In healthy subjects the peripapillary part of the choroid starts filling at distinctly lower ocular perfusion pressures than other parts of the choroid. The mean difference in perfusion pressure between peripapillary and perimacular filling was 13.6 mmHg in the six healthy subjects. A different filling pattern of the choroid was found in the seven glaucoma patients. The mean difference in perfusion pressure between the beginning of peripapillary and the beginning of perimacular perfusion of the choroid was found to be as small as 1.9 mmHg. That the filling of the peripapillary choroid observed by PVA in healthy subjects is found to start at lower perfusion pressures than in the other parts is explained by autoregulative dilatation of the peripapillary choroidal arterioles resulting from artificially raised intraocular pressure during the PVA examination. In the poag patients the peripapillary choroidal arterioles were dilated either insufficiently or not at all. The following conclusions are drawn: (1) The peripapillary choroid of healthy persons shows effective autoregulation securing the blood supply to the prelaminar part of the optic nerve. (2) In poag the peripapillary choroid has lost the capability of effective autoregulation.

Adult↗
PubMed1992

Comparative experimental biomechanical study of different types of stabilization methods of the lower cervical spine.

In a comparative experimental biodynamic study using thirty-two human cervical spines of cadavers the primary stabilization effect of different types of spondylodesis was examined. Whereas in flexion stress all methods showed a sufficient stability, the rotation tests proved, that in case of a dorsal instability of the lower cervical spine, posterior interlaminar wiring or anterior plate stabilization showed no reliable stabilization effect. However, the compression clamps by ROOSEN and TRAUSCHEL as well as the hook-plates by MAGERL are suitable dorsal stabilization methods with excellent rotation stability. In case of dorsal instability of the lower cervical spine a posterior spondylodesis is necessary and sufficient.

Biomechanical Phenomena↗
PubMed1992

Pr VECPs related to ciliary perfusion pressure in primary open angle glaucoma. A study using contact lenses to compensate for refraction changes during artificially raised IOP.

Pr VECP studies in glaucoma patients with the IOP raised artificially by the suction cup method have recently been performed by several authors, who arrived at different results. The reason for those differences may be the changes employed. The refraction changes depend on the shape of the suction cup and the height of the artificial IOP raise. By using contact lenses and a suitably shaped suction cup refraction changes could be compensated for. Studies of the pr VECP with suction cup IOP elevation and simultaneous compensation for refraction changes by applying contact lenses were made on 17 patients with primary open angle glaucoma and 21 healthy volunteers. In healthy subjects pr VECP amplitudes were found unaltered or even slightly increased until 120 mmHg of negative pressure were reached in the cup. Beyond that range they dropped. Latencies remained unaltered over that range of negative pressures. Plotting the pr VECP amplitudes and latencies against ciliary perfusion pressure we obtained unaltered potentials over a range of ca. 20 mmHg, which we interpreted as autoregulative capacity. In the 17 glaucoma patients various degrees of impaired autoregulation were found corresponding to the progression of glaucoma damage.

Adult↗
PubMed1992

[White-noise field campimetry before and after artificial increase of intraocular pressure. Possible applications in diagnosis and evaluation of glaucoma].

A total of 173 eyes (visual field defect stages O-V) of 99 glaucoma patients were investigated by means of conventional threshold-oriented suprathreshold automated test point perimetry using the Tübingen Automatic Perimeter (TAP) and by means of white-noise-field campimetry (flickering random dot pattern) using the Tübingen Electronic Campimeter (TEC). Most eyes were affected by primary open-angle glaucoma (119) or low tension glaucoma (35). The concordance between the two methods was good in 65 eyes (37.6%). Sufficient in 32 (18.5%) eyes, poor in 32 cases (18.5%) and inadequate in 44 eyes (25.4%). Among the last group of 44 eyes, 32 perceived a scotoma in the noise field (NF) but did not show any pathologic defect in conventional automated test point perimetry: the opposite constellation was found in only 12 eyes. In most cases, scotoma in the NF showed a change in both brightness and motion (noise) perception. No clear relationship between the type of glaucoma and a certain constellation of the aforementioned NF specifications could be found. Complete lack of noise perception in the scotoma occurred more frequently in advanced glaucoma (stage > or = IV). In 110 eyes of 63 of the glaucoma patients, white-noise-field campimetry was carried out during artificial IOP elevation achieved by suction-cup oculopression: during steplike increases of the negative pressure in the suction-cup up to maximum of 375 mmHg the following stages could be seen (the percentage of eyes that perceived each phenomena over the negative pressure range is shown in brackets): change in NF perception compared with initial findings (96.4%); impairment of central noise-field perception (78.2%); concentric constriction of NF (61.8%); complete breakdown of noise (field) perception (42.7%). A further, quantitative classification of these eyes was possible by evaluation of the negative pressure in the suction-cup that led to any one of these NF phenomena. The results demonstrate the usefulness of white-noise-field campimetry as a very fast screening method for detecting glaucomatous visual field defects. It can also be performed as a pressure tolerance test and thus be used to classify glaucomatous risk stages.

Adolescent↗
PubMed1991

Biomechanics of fixation systems to the cervical spine.

The biomechanical evaluation of a cervical spine implant must include flexural and torsional testing if it is used for stabilizing a traumatic unstable motion segment. A cadaveric model is presented that allows flexural and torsional testing of a cervical spine motion segment, measuring the tilting angle, the translation, and the torsional angle. After measuring the intact segments, in the first series, a so-called posterior instability was created and stabilized posteriorly with the hook-plate and sublaminar wiring; anteriorly with the H-plate; and with combinations of these implants. In a second series, their stabilizing effect after complete discoligamentous instability was tested. With isolated posterior instability, it was found that the flexural stability is preserved, whereas torsional stability is markedly reduced. In cases of isolated posterior instability, only hook plating alone or its combination with anterior H-plating seemed to bring about a higher torsional stability than the intact specimen. In cases of complete discoligamentous instability, only anterior H-plate and posterior hook plate procedures combined or the hook plate alone was able to guarantee both torsional and flexural stability higher than the intact spine. Exclusive posterior wiring without postoperative external immobilization in complete discoligamentous instability may result in permanent subluxation of the functional unit. Exclusive anterior H-plate fixation in complete discoligamentous instability requires additional external immobilization in the postoperative phase to prevent flexion and torsion.

Biomechanical Phenomena↗