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R Zimmermann

Publications and source records attributed to R Zimmermann.

At least 73 records · Page 4Linked to original sources
PubMed2003

[Computer-assisted planning and corrective osteotomy in distal radius malunion].

Corrective osteotomy of the malunited distal radius following fracture was performed in six patients using virtual planning and computer-assisted surgery. Radius joint angles and ulnar variance were assessed by CT scan and compared with the uninvolved wrist. Dorsal tilt was improved by 6 degrees, radial inclination by 3 degrees, radius rotation by 7 degrees and ulnar variance by 4.6 mm. Results were almost equivalent to the noninvolved radius. Corrective osteotomy in extraarticular malunited distal radius fracture was optimized by computer-assisted planning and surgery.

Adult↗
PubMed2003

Sample preparation technique and white cell content influence the detectable levels of growth factors in platelet concentrates.

BACKGROUND AND OBJECTIVES: Autologous platelet concentrate (PC) is applied locally to improve wound healing and tissue repair. Previous measurements of the growth factor content of platelets have given conflicting results. To date, there is no information on the influence of different preanalytical sample-preparation methods on the detectable amount of growth factors. MATERIALS AND METHODS: We measured the level of growth factors in PCs obtained by plateletpheresis and by leukapheresis. We subjected aliquots of these components to six different preparation methods: freezing/thawing once or twice; dissolution in 0.5% Triton-X-100; and clot formation by the addition of calcium and thrombin with subsequent incubation for 1 h, for 24 h, or for 1 h followed by freezing and thawing. RESULTS: In samples dissolved in Triton-X-100, higher levels of growth factors were detected than in the other specimens. In comparison to clot formation, freezing and thawing platelets twice was equivalent with respect to the release of platelet-derived growth factor (PDGF) but superior with respect to the release of transforming growth factor-beta1 (TGF-beta1). Overall, mean levels of 4.77 x 10(-16) g of PDGF-AB, 2.2 x 10(-17) g of PDGF-BB, and 2.41 x 10(-16) g of TGF-beta1 were found per single human platelet in white blood cell (WBC)-poor samples dissolved in Triton-X-100. CONCLUSIONS: Dissolving PC in Triton-X-100 releases maximum quantities of growth factors from platelets. The release of each growth factor by any sample preparation method should be investigated and interpreted separately. The preanalytical sample-preparation method, as well as the platelet and WBC content, influence the measurable levels of growth factors in PCs. The results implicate the need to correct, considerably upwards, previous estimations of the PDGF content of platelets.

Adult↗
PubMed2003

First comparison of productivity and citrate donor load between the Trima version 4 (dual-stage filler) and the Trima Accel (single-stage filler) in the same donors.

BACKGROUND AND OBJECTIVES: Aside from new software the blood cell separator TRIMA (GambroBCT) also received a newly designed separation chamber offering a novel single stage separation technology, called Trima Accel. We evaluated this new system focusing on productivity and donor comfort by comparing it to the previous version (Trima version 4) in collecting single-donor platelet concentrates (SD-PCs) and plasma. MATERIALS AND METHODS: Each of 20 donors underwent platelet apheresis using both devices. We compared the collection efficiency (CE), the collections rate (CR), the volume of the collected plasma and the residual leukocytes. Furthermore we compared donor comfort in terms of duration of the donation, flow of citrate back to the donor and platelet and white blood cell (WBC) loss. RESULTS: While the number of collected platelets and the platelet concentration did not differ significantly between both techniques the time of the procedure was reduced by 15.6% with Trima Accel. This results in an increase of the CR and CE of 25% and 15% respectively when using Trima Accel. Log normal probability plotting of WBC counts showed that both techniques complied with the European and the US leukoreduction guidelines. The mean flow of ACDA to the donor per minute and per litre blood volume was also reduced by 20%. CONCLUSION: These data show that the Trima Accel represents a further improvement in apheresis platelet production with a better productivity and donor comfort, especially regarding the mean flow of ACDA to the donor.

Adult↗
PubMed2002

Enhanced resonant backscattering of excitons in disordered quantum wells.

A clear signature of enhanced backscattering of excitons is observed in the directional resonant Rayleigh scattering of light from localized two-dimensional excitons in disordered quantum wells. Its spectral dependence and time dynamics are measured and theoretically predicted in a quantitative way. The intensity enhancement has a large momentum span extending beyond the external light emission cone. This is a consequence of the small localization length of the exciton as a massive particle probed close to the band bottom. The localization length can be controlled by the photon kinetic energy. This constitutes a qualitative difference to backscattering phenomena in other branches of physics.

Journal Article↗
PubMed2002

Single photon ionization (SPI) via incoherent VUV-excimer light: robust and compact time-of-flight mass spectrometer for on-line, real-time process gas analysis.

Fast on-line detection of organic compounds from complex mixtures, such as industrial process gas streams, require selective and sensitive analytical methods. One feasible approach for this purpose is the use of mass spectrometry (MS) with a selective and soft (fragment-free) ionization technique, such as chemical ionization (CI) or photo ionization (PI). Single photon ionization (SPI) with vacuum ultraviolet (VUV) light is a particularly sof tionization technique, well-suited for detection of both aromatic and aliphatic species. Problematic, however, is the generation of the VUV light. In general, the vacuum ultraviolet (VUV) light sources for SPI-MS are based either on lasers (e.g., 118-nm radiation generated by frequency-tripling of the third harmonic of a Nd:YAG laser) or on conventional VUV lamps, such as deuterium lamps. Althoughthe laser-based techniques are very sophisticated and expensive, the conventional lamps have serious drawbacks regarding their optical parameters, such as low-output power, low spectral power density, and broad emission bands. In this work, a novel excimer VUV light source, in which an electron beam is used to form rare gas excimer species, is used. The excimer VUV light sourceproduces brilliant and intense VUV light. The novel VUV light source was coupled to a compact and mobile time-of-flight mass spectrometer (TOFMS). A special interface design, including optical (VUV optics) as well as electronic measures (e.g., pulsed ion extraction) was realized. The use of the excimer VUV lamp for SPI will allow the realization of very compact, rugged, and sensitive SPI-TOFMS devices, which preferably will be adapted for process analytical application or monitoring issues (e.g., chemical warfare detection). The excimer VUV-lamp technology delivers VUV light with a good beam quality and high-output power at low costs. Furthermore, it allows changing the emitted wavelength as well as the bandwidth of the excimer VUV lamp in t he 100-200-nm region by changing the gas filling. Consequently, SPI-TOFMS with an excimer light source is a fast detection technique that can be used for online monitoring, for example, in environmental studies or industrial manufacturing processes. In this paper, technology and characteristics of the new excimer light source, as well as the combination with the TOFMS, are presented. Furthermore, a first characterization of the SPI-TOFMS instrument, regarding analytical parameters such as detection limits and selectivity, is given. This includes a discussion of potential improvements that probably will be achievable within a future prototype genertation. Finally, first applications of the system for on-line measurement of organic trace species in a complex gas mixture (here, motorcycle exhaust gas) are presented.

Journal Article↗
PubMed2002

[The Rostock moulage collection].

Wax moulages are valuable witnesses of the beginning of dermatology as an independent speciality. In addition, they document changes in the allocation of clinical pictures to certain conditions. This has been due to the knowledge about new etiologies of dermatologic disorders, which have been steadily increasing since the beginning of the 20th Century. Furthermore changes in the frequency of certain diseases can be recognized to some extent. The still existing moulages of the Department of Dermatology and Venereology of Rostock offer some interesting examples.

Germany↗
PubMed2002

[Massive Gorham-Stout osteolysis of the temporal bone and the craniocervical transition].

Massive osteolysis Gorham-Stout is a rare, benign but locally aggressive angiomatosis which results in destruction and resorption of bone. The etiology and pathogenesis are undefined. The occurrence of the disease in the skull base is uncommon. A 54-year-old female presented with isolated, one-sided surditas. Eight years before the patient underwent surgery and radiation therapy for treatment of hypopharyngeal cancer. A transtemporal biopsy was taken and a highly vascularized, cystic lesion with destruction of the right occipital and temporal bone and the atlas was found. Histopathology showed thin-walled capillaries with flattened endothelial lining cells. After exclusion of malignant and infectious components the diagnosis of Gorham's disease was established. Review of the literature suggests radiation therapy as the method of choice for stopping the disease's progress. The aim of this case report is to emphasize the Gorham-Stout-Syndrome as a rare differential diagnosis for skull base lesions.

Angiomatosis↗
PubMed2002

[Delayed radial paralysis after Monteggia fracture--a case report].

Concomittant lesions of neural structures represent a rare type of complications in Monteggia's fractures. In acute fractures spontaneous neurological remission usually occurs after reduction of the dislocated radial head. In the presented case a 33-year old man experienced a trady palsy of the posterior interosseus nerve 27 years after a Monteggia's fracture with the radial head left dislocated. Following a minimal trauma in badminton a neurological deficiency probably caused by distraction occurred and resulted in impairment of wrist extension and extension of the fingers. Initiated conservative treatment including intensive physiotherapy and electrotherapy for 4 months was unsuccessful. Consecutively the radial nerve was surgically exposed and released from an entrapping and thickened arcade of Frohse. The radial head was left dislocated. Full neurological recovery was obtained 9 months after surgery.

Adolescent↗
PubMed2002

Urinary infection stones.

Infection stones make up approximately 15% of urinary stone diseases and are thus an important group. These stones are composed of struvite and/or carbonate apatite. The basic precondition for the formation of infection stones is a urease positive urinary tract infection. Urease is necessary to split urea to ammonia and CO(2). As a result, ammonia ions can form and at the same time alkaline urine develops, both being preconditions for the formation of struvite and carbonate apatite crystals. When these crystals deposit themselves infection stones form. If these infections are not treated and the stones are not removed, the kidney will be damaged. For stone removal modern methods are available, e.g. ESWL and/or instrumental urinary stone removal. Here especially less invasive methods are preferable. Any treatment must be adjusted to the patient individually. Patients should be examined frequently for recurrent urinary tract infections and stone recurrences and, newly arising infections must be resolutely treated. Good therapy and prophylaxis are possible with present-day treatment modalities.

Anti-Bacterial Agents↗
PubMed2002

[State of the art prenatal care from the Swiss viewpoint].

Prenatal care has significantly reduced perinatal and maternal mortality. Screening for maternal disease allows us to reduce or to prevent an unfavourable fetal or obstetrical outcome. Prenatal care should start with a first preconceptional visit. Folic acid intake is recommended for all reproductive-age women who are capable of becoming pregnant. The fetal nuchal translucency measurement has revolutionized prenatal care as a non-invasive, effective screening for chromosomal abnormalities and other diseases of the fetus. Vertical transmission of infections has to be prevented if possible. As an example caesarean section in combination with antiretroviral therapy reduces the transmission of HIV significantly. Screening for sexually transmitted diseases (STD) remains important as at present the incidence of STD is increasing again. In this short review on prenatal care as it is done in Switzerland, we try to enlighten its most important aspects. For the patients and your own benefit as a physician it is important to follow guidelines, although of course each patient has to be treated individually.

Critical Pathways↗
PubMed2002

[Ultrasound examinations in the context of suspected fetal malformations: satisfaction of concerned women and their appraisals].

UNLABELLED: BACKGROUND AND RESEARCH QUESTIONS: Fetal malformations can be detected at an early stage during pregnancy by today's ultrasound technology. This study examined how pregnant women appraise the application of ultrasound technology when a fetal malformation is suspected and how this appraisal is influenced by the confirmation or rejection of the diagnosis and by the subsequent course of the pregnancy. METHOD: In a prospective study 86 pregnant women for whom a fetal malformation had been suspected in an ultrasound examination were assessed at three points in time: before the ultrasound examination at a specialized centre, one to two weeks after the examination, and four weeks after giving birth or after the premature termination of pregnancy. Assessments were conducted by means of questionnaire and semi-structured interviews. RESULTS: 96.4 % of pregnant women advocated routine ultrasound examinations, irrespective of whether the suspected malformation was confirmed or not and irrespective of whether the pregnancy was continued or terminated prematurely. The women rated as being most important the medical goals of the examination (e. g. determination of the child's health status) and less so the subjective and personal goals (e. g. visualization of the child). Communicative competence in the context of the examination (e. g. quality of information) were judged less favourably than technical competence (e. g. performance of the exam). 94.2 % of the women believed that the cost of the ultrasound exam should be carried by health insurances. DISCUSSION: The findings of the study show the strong significance which prenatal ultrasound examinations have for pregnant women. Acceptance of ultrasound technology is high even when the examination results cause psychological stress. However, they also indicate that more attention should be given to aspects of communication and interaction in training and application of ultrasound technology.

Abortion, Eugenic↗
PubMed2002

[Suspected fetal malformation in ultrasound examination: effects on the psychological well-being of pregnant women].

OBJECTIVE: Today's ultrasound technology permits the detection of foetal malformations during pregnancy. This study examined pregnant women's psychological responses to a suspected fetal anomaly and the subsequent course of psychological well-being. METHOD: 86 pregnant women with a suspected fetal malformation were assessed by means of questionnaires three times: before an ultrasound examination at a specialized centre, one to two weeks after the examination, and four weeks after giving birth or after premature termination of the pregnancy. Anxiety (STAI), depression (HADS-D) and feelings towards the child were assessed. RESULTS: A suspected fetal malformation results in psychological stress with anxiety and depression levels significantly higher than in normal samples. Regardless of either confirmation or rejection of the diagnosis of a malformation, stress decreases significantly after the ultrasound examination at the specialized centre. Only women who decide to terminate the pregnancy prematurely show increasing levels of stress in this period. Four weeks after giving birth or termination of pregnancy the assessed psychological parameters of all participants fall within the normal range. CONCLUSIONS: A suspected fetal malformation results in immediate psychological stress but not in an enduring psychological disorder. Women facing immediate premature termination of pregnancy exhibited the highest stress levels. The psychosocial distress caused by the diagnosis of a fetal malformation should be taken into consideration in the psychosocial consultation and treatment of concerned women and their partners.

Abortion, Eugenic↗
PubMed2002

[Free microvascular transplantation of parts of the great toe for thumb reconstruction].

PURPOSE/BACKGROUND: A reconstructed thumb has to fulfil the function of opposition, pinch-grip, stability, sufficient length, sufficient sensibility, and painlessness. Next to pollicisation, these requirements can only be met satisfactory by the microvascular free great toe-to-hand transplantation. The goal of a thumb reconstruction is a compromise between an optimal functional and aesthetic outcome and a minimal morbidity of the donor site. METHOD AND CLINICAL MATERIAL: Depending on the extent of the traumatic thumb defect, not only the fibular part of the ipsilateral great toe but also its adjacent soft tissue and the first web space may be integrated into the vascularized transplant. The distal phalanx is reduced in width on its tibial side to integrate the second digital nerve to the transplant. The rest of the great toe is covered with the remaining sensible tibial flap. RESULTS: From 1993 to 1998, five male patients have been operated with the described method of partial great toe transfer and an additional deepening of the first web space. All reconstructions passed without complications. All patients present with a protective sensibility and a dynamic two-point discrimination between 8 and 15 mm. The average strength of the reconstructed thumb was 79 %, the strength of pinch-grip 90 % of the healthy thumb. CONCLUSION: Thumb reconstruction after traumatic amputation distal to the metacarpophalangeal joint can in our hands optimally be managed with free microvascular anastomosed parts of the great toe and its adjacent soft tissues.

Adult↗
PubMed2002

[Distal radius fractures and concomitant lesions. Experimental studies concerning the pathomechanism].

Since Colles (1814) first described a distal radius fracture and the publication by Dupuytren (1834), the frequency of and problems surrounding these fractures were increasingly recognised. Not only the treatment but also the formation and type of fracture were repeatedly analysed. The various theories concerning the pathomechanism led to names such as: "tear fracture", "bend fracture", "thrust fracture", "compression fracture", "snap fracture" and others. In our experimental studies we attempted to simulate the pathomechanism of distal radius fractures and present them pictorially. With the help of a materials testing machine, 63 prepared cadaver arms were hyperextended in the wrist joint until a radius fracture occurred. The concomitant lesions were registered radiologically and by dissection. Moreover, additional cadaver arms were deep-frozen and examined by means of computer tomography and cryosection according to Kathrein. Through experimental hyperextension it was possible to generate dorsal, central, and palmar types of fractures. We produced 42 dorsal, 14 central and 7 palmar fractures. Fundamentally, it seems that the fracture depends on the extent in which the carpal bones of the proximal row are pressed against the dorsal, central or palmar part of the articular surface of the distal radius. The subsequent dissection showed in 40 cases (63 %) mostly multiple concomitant lesions and in 23 cases (37 %) none of these. The reason for concomitant lesions may be the proportion of bone stability to the strength of ligaments. Most frequently (27 cases, i.e. 43 %), we found a destabilisation of the articular disk with or without a bony avulsion fragment (fracture of the ulnar styloid). We also commonly found ruptures of the interosseous ligaments between scaphoid and lunate (20 cases, i.e. 32 %) and lunate and triquetrum (11 cases, i.e. 18 %). It is difficult to apply knowledge gained from experimental studies on preserved cadaver arms clinically. There are of course no physiological reflexes and the slow fracture process must be taken into consideration. This holds true not only for concomitant lesions but also for the type of fracture. On the other hand, in these experimental studies it was possible to generate many realistic types of fractures with their concomitant lesions.

Biomechanical Phenomena↗
PubMed2002

[Suspected fetal malformation in ultrasound examination: The partner's distress and attitudes towards ultrasound. Technology].

AIM: The involvement of fathers in the preparation for birth was a major progress in modern obstetrics. The present study investigates how fathers evaluate the ultrasound examination during pregnancy and how much they are stressed by the diagnosis of a possible fetal developmental disturbance. METHOD: In a specialized ultrasound center at the University Hospital in Zurich 54 couples who came in with the diagnosis of a possible fetal developmental disturbance were interviewed for their emotional stress and attitudes towards ultrasound examinations during pregnancy. RESULTS: Levels of state anxiety were significantly above the norm for both men and women. However, male partners felt less stressed and experienced less anxiety than the pregnant women. Men were also more optimistic about the health status of the unborn baby. There were no differences in attitudes towards ultrasound examination between women and their male partners, however, men rated their experiences with ultrasound examinations more critical and knew less about it. The support of ultrasound as a routine examination method during pregnancy was high in both sexes. CONCLUSION: The diagnosis of a possible fetal developmental disturbance is a big emotional distress for pregnant women and the fathers of the baby. It does not result in a negative attitude towards ultrasound examination, though.

Anxiety↗
PubMed2002

Troponin T concentrations 72 hours after myocardial infarction as a serological estimate of infarct size.

BACKGROUND: After acute myocardial infarction, the structural protein T is released considerably longer than cytosolic creatine kinase (CK), CK MB isoenzyme (CK-MB), or lactate dehydrogenase (LDH) and late troponin T release (> 48 hours after onset of chest pain) appears to be less affected by early coronary reperfusion. OBJECTIVE: To investigate the precision of a single measurement of circulating troponin T concentrations 72 hours after onset of chest pain compared with standard scintigraphic and enzymatic estimates of myocardial infarct size. METHODS: Quantitative single photon emission computed tomography thallium-201 scintigraphy at rest was performed in 37 patients 2-3 weeks after myocardial infarction (group 1: 14 patients without early coronary reperfusion; group 2: 23 patients with early reperfusion achieved by thrombolytic therapy, by percutaneous transluminal coronary angioplasty, or by both). RESULTS: In both groups, the number of myocardial segments with abnormal thallium-201 uptake indicating the individual extent of irreversible myocardial damage correlated significantly with the troponin T concentrations 72 hours after infarction as well as with peak concentrations of CK, CK-MB, and LDH. CONCLUSION: The data show that a single measurement of circulating troponin T 72 hours after onset of chest pain--independent of reperfusion--is superior for the estimation of myocardial infarct size to measurement of peak CK, CK-MB, or LDH, which require serial determinations and depend on coronary reperfusion.

Adult↗