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C Wimmer

Publications and source records attributed to C Wimmer.

At least 55 records · Page 3Linked to original sources
PubMed1999

Measurement of vertebral rotation: a comparison of two methods based on CT scans.

This study compared Ho's and Aaro's method to measure vertebral axial rotation in order to find the more accurate one. Two hundred fifty-nine CT scans were taken from 11 cadaver vertebrae. The scans were performed with vertebrae in neutral position and angulated up to 20 degrees in the sagittal and frontal plane to simulate kyphosis/lordosis and side bending. Axial rotation was measured according to both methods. The mean difference between true and measured values was 3.7 +/- 6.7 (95% confidence limit) (Ho's method) and 2.3 +/- 3.7 (Aaro's method), respectively. Correlation with true axial rotation was r2 = 0.66 (Ho's method) and r2 = 0.77 (Aaro's method). We recommend using Aaro's method as the more accurate measure of axial rotation in scoliotic vertebrae.

Cadaver↗
PubMed1998

Gos1p, a Saccharomyces cerevisiae SNARE protein involved in Golgi transport.

Specific transport between secretory compartments requires that vesicular carriers contain targeting proteins known as SNAREs. Ten v-SNAREs have been identified in the genome of the yeast Saccharomyces cerevisiae by sequence analysis. We report here the characterization of Gos1p, a v-SNARE localized to the Golgi compartment and likely homolog of the mammalian protein GOS-28/GS28. Gos1p is a type II membrane protein with characteristic SNARE sequence hallmarks and is functionally a SNARE protein. Gos1p was originally identified as a 28 kDa protein in an immunoprecipitate of the cis-Golgi t-SNARE Sed5p. This interaction between Sed5p and Gos1p is direct as demonstrated by in vitro binding with recombinant proteins. Deletion of GOS1 results in viable haploids with modest growth and secretory defects. Close examination of the secretory phenotype of GOS1-disrupted cells suggests that Gos1p may play a role in multiple transport steps, specifically ER-Golgi and/or intra-Golgi transport.

Biological Transport↗
PubMed1998

The SNARE machinery is involved in apical plasma membrane trafficking in MDCK cells.

We have investigated the controversial involvement of components of the SNARE (soluble N-ethyl maleimide-sensitive factor [NSF] attachment protein [SNAP] receptor) machinery in membrane traffic to the apical plasma membrane of polarized epithelial (MDCK) cells. Overexpression of syntaxin 3, but not of syntaxins 2 or 4, caused an inhibition of TGN to apical transport and apical recycling, and leads to an accumulation of small vesicles underneath the apical plasma membrane. All other tested transport steps were unaffected by syntaxin 3 overexpression. Botulinum neurotoxin E, which cleaves SNAP-23, and antibodies against alpha-SNAP inhibit both TGN to apical and basolateral transport in a reconstituted in vitro system. In contrast, we find no evidence for an involvement of N-ethyl maleimide-sensitive factor in TGN to apical transport, whereas basolateral transport is NSF-dependent. We conclude that syntaxin 3, SNAP-23, and alpha-SNAP are involved in apical membrane fusion. These results demonstrate that vesicle fusion with the apical plasma membrane does not use a mechanism that is entirely unrelated to other cellular membrane fusion events, but uses isoforms of components of the SNARE machinery, which suggests that they play a role in providing specificity to polarized membrane traffic.

Animals↗
PubMed1998

Arrangement of subunits in 20 S particles consisting of NSF, SNAPs, and SNARE complexes.

The structure of 20 S particles, consisting of NSF, SNAPs, and SNARE complexes, was analyzed by electron microscopy and fluorescence resonance energy transfer. Structural changes associated with the binding of alpha-SNAP and NSF to SNARE complexes define the contribution of each component to the 20 S particle structure. The synaptic SNARE complex forms a 2.5 x 15 nm rod. alpha-SNAP binds laterally to the rod, increasing its width but not its length. NSF binds to one end of the SNAP/SNARE complex; the resulting 20 S particles measure 22 nm in length and vary in width from 6 nm at their narrowest point to 13.5 nm at their widest. The transmembrane domains of VAMP and syntaxin emerge together at the NSF-distal end of 20 S particles, adjacent to the amino terminus of alpha-SNAP.

Adenosine Triphosphate↗
PubMed1998

The plant PTS1 receptor: similarities and differences to its human and yeast counterparts.

Two targeting signals, PTS1 and PTS2, mediate import of proteins into the peroxisomal matrix. We have cloned and sequenced the watermelon (Citrullus vulgaris) cDNA homologue to the PTS1 receptor gene (PEX5). Its gene product, CvPex5p, belongs to the family of tetratricopeptide repeat (TPR) containing proteins like the human and yeast counterparts, and exhibits 11 repeats of the sequence W-X2-(E/S)-(Y/F/Q) in its N-terminal half. According to fractionation studies the plant Pex5p is located mainly in the cytosolic fraction and therefore could function as a cycling receptor between the cytosol and glyoxysomes, as has been proposed for the Pex5p of human and some yeast peroxisomes. Transformation of the Hansenula polymorpha peroxisome deficient pex5 mutant with watermelon PEX5 resulted in restoration of peroxisome formation and the synthesis of additional membranes surrounding the peroxisomes. These structures are labeled in immunogold experiments using antibodies against the Hansenula polymorpha integral membrane protein Pex3p, confirming their peroxisomal nature. The plant Pex5p was localized by immunogold labelling mainly in the cytosol of the yeast, but also inside the newly formed peroxisomes. However, import of the PTS1 protein alcohol oxidase is only partially restored by CvPex5p.

Amino Acid Sequence↗
PubMed1998

Predisposing factors for infection in spine surgery: a survey of 850 spinal procedures.

A retrospective survey of 850 spinal procedures was conducted to determine risk factors for postoperative spinal infection. Some 574 posterior and 276 anterior procedures were evaluated. Infections were classed as early (within 19 weeks postoperatively) and late (> or = 20 weeks postoperatively), as well as deep and superficial infections. Previously postulated risk factors (i.e., diabetes, corticosteroid therapy, previous spinal surgery, obesity, chronic infection, and smoking) were investigated. Furthermore, it was hypothesized that three additional factors: extended preoperative hospitalization, prolonged operation duration, and high blood loss were risk factors not previously considered. A postoperative infection was evident in 22 of 850 procedures (19 early/three late infections, four superficial/18 deep infections). Most infections (n = 21) occurred with posterior instrumentation. Previously described factors were proven as risk factors. Extended preoperative hospitalization (p < 0.04), high blood loss (p < 0.01), and prolonged operation time (p < 0.001) were additionally determined as risk factors. The results suggest that routine prophylactic antibiotics might be unnecessary in anterior surgery, whereas extended prophylactics should be considered in posterior instrumentation, especially when risk factors are apparent.

Adolescent↗
PubMed1998

Aseptic loosening after CD instrumentation in the treatment of scoliosis: a report about eight cases.

We report eight patients who had had operative treatment of idiopathic scoliosis with CD instrumentation and developed radiolucency around pedicle screws and a discharging sinus. There are two recent reports (Dubousset J, Shuffleberger H, Wenger D. Late infection with CD instrumentation. Orthop Trans 18:121, 1994; Richards BS. Delayed infections following posterior spinal instrumentation for the treatment of idiopathic scoliosis. J Bone Joint Surg [Am] 4:524-529, 1995) describing delayed infection with spontaneous drainage after the treatment of scoliosis with CD instrumentation and Texas Scottish Rite Hospital system with controversial results. Eight patients had radiologic signs of implant loosening after a mean of 7 months, with radiolucency around the pedicle screws. Six patients developed a painful swelling and a discharging sinus after a mean of 21 months. Histopathologic results showed metal wear and chronic inflammatory reaction with granuloma formation. No evidence of pyogenic infection was present. We believe that this complication is caused by micromotion.

Adolescent↗
PubMed1998

Influence of antibiotics on infection in spinal surgery: a prospective study of 110 patients.

The purpose of this prospective study was to evaluate the effect of prophylactic antibiotic treatment on postoperative antibiotic spinal wound infection after spinal surgery with instrumentation. Subjects consisted of 110 successive patients that underwent instrumented fusion with Cotrel-Dubousset (CD) or Miami Moss instrumentation. In 56 cases, the indication for surgery was painful spondylolisthesis. The remaining 54 patients were treated for idiopathic scoliosis. In total, 172 spinal procedures were performed and included in the study. Preoperative infection prophylaxis consisting of 2 g cefamandole was administered to all patients. Patients received three doses of 2 g/day cefamandole after surgery for 3 days. Follow-up ranged from 1 to 4 years. The study revealed an early infection in one (0.6%) of the 172 procedures in a patient with spondylolisthesis. A late infection occurred in one (0.6%) patient with the diagnosis of idiopathic scoliosis. In both cases, cultures were positive for Staphylococcus aureus.

Adolescent↗
PubMed1997

[Biomechanics of lumbar instability].

Several authors have tried to define segmental lumbar instability. Their definitions: increased antero-posterior translation, pathologic coupled motion, increased neutral zone, pathologic instantaneous center of rotation describe some mechanic findings occurring in the aging spine. However, there is no evidence that they help to differentiate the pathologic entity of segmental lumbar instability from the normal aging process. Dynamic explanation models are promising but at the moment they cannot be used clinically for diagnosis of instability as well. The most important structure to maintain lumbar stability is the intervertebral disc. In the third and fourth decade, more than 50 percent of specimen show peripheral tears of the anulus. It was shown in animal experiments that these tears develop to radial tears, which are accompanied by nuclear volume loss and decreased height. The facets degenerate one or two decades later. Corresponding with the loss of discal function, they increasingly contribute to spinal stability. In conclusion, the concept of lumbar segmental instability is not very helpful in clinical practise. It is recommended to base the decision of lumbar fusion on a painful degenerated disc, and additional findings promising a good result.

Animals↗
PubMed1997

[Minimally invasive approach and surgical procedures in the lumbar spine].

The history of minimally invasive lumbar spine surgery began in 1963 with the introduction of chemonucleolysis. Like this technique, the later development of mechanical nucleotomy and lasernucleotomy aimed primarily at reduction of the disc pressure. Miniature optical systems offered the opportunity for more specific decompression by discoscopy or, more recently, by transforaminal epiduroscopy. Initially, nucleotomy was the only feasible minimally invasive procedure. In recent years, however, minimally invasive spinal fusion became possible due to the development of new devices (Cages) and advanced transperitoneal (laparoscopic) and retroperitoneal approaches.

Decompression, Surgical↗
PubMed1997

[Advantages and disadvantages of retro- and transperitoneal approach for fusion of the presacral intervertebral disk].

In a retrospective study, we evaluated 180 patients treated for painful spondylolisthesis with combined anterior and posterior fusion. Group I included 90 patients treated by anterior fusion with the transperitoneal approach. Group II included 90 patients operated on with a retroperitoneal approach. Group II showed a higher incidence of pseudarthrosis L5/S1 (4%), tear of the common iliac vein (1%), postsympathectomy syndrome (4%) and reversible L4 nerve-root lesion (3%). On the basis of our findings, we recommend the transperitoneal approach for anterior interbody fusion L5 to S1 or L4 to S1.

Adolescent↗
PubMed1997

[Lumbar fusion in adults--dorsal or combined ventral/dorsal approach?].

A retrospective study was conducted to compare the results of posterior with combined anterior/posterior lumbar fusion in adults. Seventy-six consecutive posterior cases fused with pedicle screws and 46 combined cases were included and followed for at least 2 years. Subjective assessment was based on the Visual Analogue Scales, Waddel Disability and Impairment Score and the GBB for objective quantification of complaints. Furthermore, a thorough clinical examination was done and X-rays including flexion/ extension radiographs, were taken. Questions were asked about the occupational status as well. Pain decreased significantly more in the combined cases than in the posterior fusion cases. In one case a lesion of the common iliac vein occurred during a retroperitoneal approach. Only about half the patients working preoperatively returned to work again. In conclusion, the benefit of better pain relief after combined fusion must be regarded in relation to a higher complication rate due to a second approach.

Adult↗
PubMed1997

[Hypercholesteremia and hyperfibrinogenemia in sudden deafness].

BACKGROUND: The pathogenesis of sudden hearing loss has not been elucidated as yet. Insufficient perfusion of the cochlea due to an increased blood viscosity, microthrombosis, or altered vasomotion are assumed. Hypercholesterolemia and hyperfibrinogenemia are frequently observed in patients with sudden sensorineural hearing loss. The aim of this study was to investigate the incidence of hypercholesterolemia and hyperfibrinogenemia in patients suffering from sudden hearing loss compared to normal controls. In an intervention study the impact of drastic lowering of plasma cholesterol and fibrinogen by a selective extracorporal apheresis was studied. METHODS: In a case-control study of 23 patients suffering from sudden hearing loss, plasma cholesterol and fibrinogen levels as well as erythrocyte aggregation and plasma viscosity were determined. Seven sudden hearing loss patients from this group were treated with H.E.L.P. apheresis, an extracorporal procedure removing fibrinogen and idl-cholesterol from plasma. RESULTS: Plasma fibrinogen and cholesterol levels were higher in sudden hearing loss patients, leading to significantly elevated values of erythrocyte aggregation and plasmaviscosity. Six out of the seven patients treated with a single H.E.L.P. apheresis immediately showed an improvement of auditory thresholds. CONCLUSIONS: We conclude that hyperfibrinogenemia and hypercholesterolemia may contribute to the clinical event of sudden hearing loss. Our study shows for the first time that acute and drastic removal of plasma fibrinogen and low density lipoproteins can be an effective clinical tool in the treatment of patients with sudden hearing loss.

Adult↗
PubMed1997

AP-translation in the proximal disc adjacent to lumbar spine fusion. A retrospective comparison of mono- and polysegmental fusion in 120 patients.

120 consecutive patients with painful spondylolisthesis underwent combined anterior and posterior fusion. Patients were divided retrospectively into two groups. In group I, 46 patients were treated with monosegmental fusion. In group II, 74 had polysegmental fusion. The mean follow-up time was 3 (2-7) years. Anterior posterior (AP)-translation in the first disc superior to fusion was measured according to Wiltse and Winter (1983). In group I, 3 and in group II, 10 patients developed an AP-translation of more then 3 mm in the disc adjacent to the fusion. AP-translation correlated with the number of fused segments and the follow-up time.

Adolescent↗
PubMed1997

Conservative treatment of tuberculous spondylitis: a long-term follow-up study.

A retrospective follow-up study was performed on 40 patients, in which tuberculous spondylitis was treated conservatively between 1969 and 1985 with orthotic supports for an average of 16 months (range, 10-30 months) and with anti-tuberculous agents. All had persistent back pain, but none had neurological deficits. The mean follow-up period was 17 years (range, 10-26 years). Diagnosis was confirmed histopathologically. The spinal segments involved ranged from T5 to L5. The kyphotic angle was calculated according to Cobb. At final follow-up, 22 patients were pain free, 11 had occasional pain, 6 complained of pain in the morning, and 1 had chronic pain and needed frequent analgesics. Solid bony union was found in 75% of patients. The kyphotic deformity occurred in the thoracic spine with a mean angle of 20 degrees (range, 13-28 degrees) and in the lumbar spine with a mean angle 12 degrees (range, 5-26 degrees). The long-term follow-up of conservative treatment showed only slightly increased kyphosis. Conservative treatment is an alternative to surgical intervention in cases with kyphosis < 35 degrees.

Adult↗
PubMed1997

The relation between chemically measured total iron-binding capacity concentrations and immunologically measured transferrin concentrations in human serum.

We sought to determine if serum total iron-binding capacity (TIBC) is equivalent to serum transferrin (TRF) so that a low-cost colorimetric chemical assay for unsaturated iron-binding capacity (UIBC) could be substituted for a high-cost immunologic assay for TRF. Our study design included independent and blinded measurements of UIBC, serum iron, and TRF concentrations in human serum samples. Data from five independent correlation studies carried out at three different Quest Diagnostics laboratories were combined into one data set containing 570 paired results for TIBC and TRF. r2 was 0.941 when three outliers were eliminated from the 570-sample data set. Scatter about the regression line was fully accounted for by the CVs for the TIBC and TRF assays. When each test is measured precisely and without bias, the ratio of TIBC (mumol/L) to TRF (g/L) in SI units is close to the theoretically expected value of 25.0.

Colorimetry↗
PubMed1996

The possibility of creating lordosis and correcting scoliosis simultaneously after partial disc removal. Balance lines of lumbar motion segments.

STUDY DESIGN: The feasibility of correcting scoliosis and creating lordosis simultaneously in the thoracolumbar and lumbar spine by anterior instrumentation was investigated by in vitro testing. OBJECTIVES: To evaluate the vertebral zones in which a compressive load applied in a motion segment creates side bending and lordosis in intact motion segments and after partial disc removal. SUMMARY OF BACKGROUND DATA: Most investigators have observed a kyphogenic effect of anterior scoliosis instrumentation and recommended dorsal placement of screws and the use of wedge grafts, although wedge grafts were not used routinely by all surgeons. METHODS: Zones of lordosization and side bending were determined by evaluation of balance lines between extension-flexion and side bending, respectively, by axial loading on ligamentous human motion segments with intact discs and after partial disc removal. RESULTS: In lumbar motion segments with intact discs, it is possible to achieve ipsilateral side bending and lordosization by anterior instrumentation. After partial disc removal, the balance line between extension and flexion runs through the ipsilateral pedicle, and, therefore, a compressive load between the vertebral bodies always creates kyphosis. CONCLUSIONS: After partial disc removal, it is not possible to create lordosis and correction of scoliosis simultaneously by ipsilateral anterior instrumentation without the use of intervertebral wedge grafts.

Adult↗