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J Schubert

Publications and source records attributed to J Schubert.

At least 55 records · Page 3Linked to original sources
PubMed2002

Study by finite element method of the mechanical stress of selected biodegradable osteosynthesis screws in sagittal ramus osteotomy.

We tested the stability of the bilateral sagittal split osteotomy using four resorbable osteosynthesis screws (the PLLA screw introduced by Harada and Enomoto, the Isosorb screw, the BioSorbFX screw and the Lactosorb screw) which are all currently in clinical use. The distribution of stress in both the bicortically inserted screws and the adjacent bone of a computer-generated mandible was recorded by the three-dimensional finite element method. The stress of the materials under investigation was postulated to have reached threshold values for stability, and maximum chewing forces of 132 N (Harada and Enomoto), 117 N (Isosorb), 115 N (BioSorbFX) and 46.4 N (Lactosorb) were determined. As far as the postoperative chewing forces were concerned, all four screws were sufficiently stable at the osteotomy gap. Finite element modelling seems to be an appropriate method of investigating these clinical issues when the mechanical stress both in implants and in the adjacent bone is taken into account.

Absorbable Implants↗
PubMed2002

B group vitamins and cleft lip and cleft palate.

B group vitamins including folic acid supplementation during pregnancy have been shown to be effective in preventing cleft lip and palate (CLP) in humans. The clinical trials for the prevention of malformation have been mostly empirically based. The aim of the present study was directed toward the elucidation of the mechanisms underlying the preventive measures. The teratogenic potency of vitamin deficiency over the whole period of gestation (days 1-18) and of food restriction during the critical period of palatogenesis (days 12 and 13) were investigated in the genetically different strains of NMRI and A/WySn mice. Furthermore the potential benefit of vitamin B supplementation/treatment in the genetically susceptible CLP strain was demonstrated for comparison with former work on a teratogenetically induced cleft palate model. The results illustrate the higher susceptibility of the NMRI strain to the teratogenic action of deficiency (increase of the CP rate from 3.8% to 25%) in contrast to A/WySn mice, which actually have a high spontaneous but relative teratogenic-resistant clefting rate (28-44%). A deficiency of each of the individual B vitamins is teratogenic, however total B group deficiency has the strongest effect in the case of deficiency of all B vitamins. This produces up to 25% cleft palates in the NMRI strain. Alternatively, vitamin B group treatment in pregnant A/WySn mice did not substantially influence the clefting rate in contrast to our former experience in Halle:AB mice. The results may help to elucidate the interplay of genetic conditions and exogenous (nutritional) factors in both the aetiology and prevention of CLP. This may further clarify the role of the B vitamins in empiric preventive clinical trials.

Animals↗
PubMed2001

[Post-traumatic and postoperative asymptomatic urinoma. 2 case reports].

A urinoma is a collection of extravasated urine developing after injury to the urinary tract, almost always asymptomatic, but requiring urgent surgical treatment. A Medline search for the term urinoma in publications appearing between 1996 and 1998, turned up only two reports describing an asymptomatic course. We now describe two cases of urinomas that remained asymptomatic over a period of four months. Although initially misinterpreted, a subsequent revisionary operation nevertheless resulted in a cure. In case 1, the urinoma appeared after an operation to treat recurrent rectal cancer; in case 2, the causal mechanism was an avulsed ureter. Treatment is orientated to the location (intra- or retroperitoneal) and extent of the injury, and comprises temporary stenting, drainage and, where necessary, plastic reconstruction. Even in the absence of a clinical correlate, any urinary retention newly discovered on ultrasonography must be investigated by uroradiography.

Adult↗
PubMed2001

The variability of hop latent viroid as induced upon heat treatment.

We have previously shown that heat treatment of hop plants infected by hop latent viroid (HLVd) reduces viroid levels. Here we investigate whether such heat treatment leads to the accumulation of sequence variability in HLVd. We observed a negligible level of mutated variants in HLVd under standard cultivation conditions. In contrast, the heat treatment of hop led to HLVd degradation and, simultaneously, to a significant increase in sequence variations, as judged from temperature gradient-gel electrophoresis analysis and cDNA library screening by DNA heteroduplex analysis. Thirty-one cDNA clones (9.8%) were identified as deviating forms. Sequencing showed mostly the presence of quadruple and triple mutants, suggesting an accumulation of mutations in HLVd during successive replication cycles. Sixty-nine percent of base changes were localised in the left half and 31% in the right half of the secondary structure proposed for this viroid. No mutations were found in the central part of the upper conserved region. A "hot spot" region was identified in a domain known as a "pathogenicity domain" in the group representative, potato spindle tuber viroid. Most mutations are predicted to destabilise HLVd secondary structure. All mutated cDNAs, however, were infectious and evolved into complex progeny populations containing molecular variants maintained at low levels.

Base Sequence↗
PubMed2001

The human GPI1 gene is required for efficient glycosylphosphatidylinositol biosynthesis.

The first step in glycosylphosphatidylinositol (GPI) membrane anchor biosynthesis that is defective in paroxysmal nocturnal haemoglobinuria is mediated by an N-acetylglucosaminyl transferase expressed in the endoplasmic reticulum. Six human genes encode subunits of this enzyme, namely PIG-A, PIG-C, PIG-H, PIG-P, GPI1, and DPM2. Here, the human GPI1 gene is characterised. This gene is organised into eleven exons. The locus was mapped to chromosome 16p13.3 near the haemoglobin alpha chain locus. GPI1 is expressed ubiquitously in human cells and tissues. Expression levels are markedly elevated in haematopoietic tissues (bone marrow, foetal liver). To determine whether human GPI1 is essential for human GPI biosynthesis, antisense RNA was expressed in HEK293 cells. Transfectants exhibited a marked but incomplete decrease in the expression of a GPI-linked reporter protein, confirming that GPI1 is required for efficient GPI biosynthesis. In contrast, expression of GPI-linked proteins is normal in lymphatic cell lines from individuals with the alpha thalassaemia/mental retardation syndrome, which is characterised by large deletions from chromosome 16p removing one of the two GPI1 alleles along with the haemoglobin alpha locus. In conclusion, GPI1 plays an important role in the biosynthesis of GPI intermediates. Due to its autosomal localisation, the heterozygous deletion of GPI1 does not lead to an overt defect in the expression of GPI-linked proteins.

Cell Line, Transformed↗
PubMed2001

Preceding infections, immune factors, and outcome in Guillain-Barré syndrome.

OBJECTIVE: To test the hypothesis that different preceding infections influence the neurophysiologic classification and clinical features of Guillain-Barré syndrome (GBS). METHODS: We tested pretreatment sera, 7 +/- 3 (mean +/- SD) days from onset, from 229 patients with GBS in a multicenter trial of plasma exchange and immunoglobulin, for serological markers of infection, adhesion molecules, and cytokine receptors, and compared these with neurophysiologic and clinical features. RESULTS: Recent infection by Campylobacter jejuni was found in 53 patients (23%), cytomegalovirus in 19 (8%), and Epstein-Barr virus in four (2%). Patients with C. jejuni infection were more likely than others to have neurophysiologic criteria of axonal neuropathy or inexcitable nerves, antiganglioside GM(1) antibodies, pure motor GBS, lower CSF protein, and worse outcome. Patients with cytomegalovirus infection were younger and more likely than others to have raised serum concentrations of molecules important in T lymphocyte activation and migration, soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble leukocyte selectin, and soluble interleukin-2 receptor (sIL-2R). Concentrations of sICAM-1 and soluble tumor necrosis factor receptor were higher in patients with inexcitable nerves than those with demyelinating neurophysiology. Logistic regression analysis showed death or inability to walk unaided at 48 weeks were associated with diarrhea, inexcitable nerves, severe arm weakness, age over 50, raised sIL-2R concentration and absence of immunoglobulin (Ig) M antiganglioside GM(1) antibodies. CONCLUSIONS: Subtypes of GBS defined by preceding infections were only approximately associated with different patterns of clinical, neurophysiologic, and immunologic features. A single infectious agent caused more than one type of pathology in GBS, implying interaction with additional host factors. Most patients had no identified infection.

Antibodies↗
PubMed2001

The male chronic pelvic pain syndrome.

Suffering chronic pain is a common and debilitating problem that significantly impairs the quality of life of affected patients. Because we continue to struggle with chronic pelvic pain disorders both diagnostically and therapeutically, a neuro-behavioral perspective should be used in an attempt to explain pathways and neurophysiological mechanisms, and to improve diagnostics and treatment of male pelvic pain. First, however, malignant and acute/chronic bacterial disease has to be excluded as a cause of chronic pain in every single case. Then diagnostic approaches should screen for lower urinary tract dysfunction, pelvic floor functional disorders, and disturbed reflex integrity within the pelvic area. Treatment approaches for the male chronic pelvic pain syndrome could be divided into causal and symptomatic. Causal treatment approaches try to influence basic mechanisms generating and supporting chronic pain. In most cases a symptomatic approach is needed to relieve pain immediately. Because generally accepted treatment protocols and studies are missing, the following approach in the individual patient is recommended: (1) symptomatic treatment for immediate pain relief, (2) diagnostic work-up, (3) causal treatment trial.

Biofeedback, Psychology↗
PubMed2001

[Complications in surgical treatment of malocclusions. Report of 50 years experience].

BACKGROUND: During the past few decades, orthognathic surgery has become routine in oral and maxillofacial surgery. As these surgical interventions are elective, the goal is a low complication rate. The aim of this study was to analyze the intraoperative and postoperative complications after orthognathic surgery without considering orthodontic relapse. PATIENTS AND METHODS: The medical files of 507 patients were reviewed who had been treated in the department of oral maxillofacial surgery at the Martin-Luther-Universität in Halle-Wittenberg during a period of 51 years. The indication for orthognathic surgery was mandibular hyperplasia in 314 cases (61.9%), mandibular hypoplasia in 69 cases (13.6%), mandibular hyperplasia with a frontal open bite in 53 cases (10.5%), maxillary hyperplasia with a cleft in 30 cases (5.9%), maxillary hyperplasia in 22 cases (4.3%), severe laterognathia in 10 cases (2.1%), and isolated frontal open bite in 9 cases (1.5%). The surgical procedures were as follows: bilateral sagittal split osteotomy (n = 336, 66%), Le Fort I osteotomy (n = 29, 5.9%), bimaxillary osteotomy (n = 35, 6.3%), and segment osteotomy (n = 107, 21.1%). Rigid fixation was used in 147 patients. RESULTS: In 55% of the patients a postoperative neurosensory deficit of the inferior alveolar nerve was observed, which was only found in 28% after 1 year. Inflammatory wound healing was found in 5.3% of the patients. CONCLUSION: Due to antibiotic perioperative prophylaxis and modern rigid osteosynthesis devices, orthognathic surgery has become a routine method in maxillofacial surgery with predictable surgical results.

Cross-Sectional Studies↗
PubMed2001

[Finite element assisted study of the mechanical stability of 2 selected osteosynthesis systems for mandibular osteotomy].

The aim of this study was to use the finite element method (FEM) to compare the stability of 2.0 mm titanium screws in a triangular configuration with that of a 2.0 mm titanium miniplate as osteosynthesis material following bilateral sagittal split osteotomy. To this end, a model of the mandible was produced, consisting of 19,854 elements and 4285 nodes. The mechanical parameters of the materials investigated were taken from the literature or notified by the manufacturer. On condition that the materials were subjected only to their respective ultimate tensile stress, it was possible to neutralise the following masticatory force: 124.6 N with the miniplate and 167.5 N with the bicortical triangular screw configuration. The limitation of stress ensued from the peri-implant bone and not from the osteosynthesis material per se. The finite element method (FEM) appears to be suitable for simulating complex mechanical stress situations in the maxillofacial area, as also demonstrated by the fact that our data agree with those in the literature and with clinical experience. It will enable considerable savings to be made in terms of time and materials (animal experiments) in the future development of osteosynthesis materials and techniques.

Biomechanical Phenomena↗
PubMed2001

Renal carcinoma with caval vein infiltration and triple coronary disease: one-stage surgical management.

We report the one-stage surgical management in a 68-year-old patient with a renal cell carcinoma with extended intravascular growth into the inferior vena cava combined with severe triple coronary artery disease. After nephrectomy the resection of the intravascular tumor and caval reconstruction were performed in deep hypothermic circulatory arrest. Coronary revascularization was accomplished while rewarming. The postoperative course was uneventful. Nine months after this operation there are no signs of reoccurrence.

Aged↗
PubMed2001

Evaluation of a pan-reactive hantavirus enzyme immunoassay and of a hantavirus immunoblot for the diagnosis of nephropathia epidemica.

BACKGROUND: Nephropathia epidemica (NE) caused by the hantavirus serotype Puumala (PUUV) is endemic in large parts of Europe. The prognosis of this disease is usually good. However, a rapid serological diagnosis is important to differentiate NE from potentially more severe renal conditions. OBJECTIVE: To evaluate the diagnostic usefulness of a novel pan-reactive hantavirus enzyme immunoassay (EIA) and of a novel hantavirus immunoblot (IB). STUDY DESIGN: Three groups of serum samples were tested with both assays: 79 samples from 43 patients with acute NE, 27 samples from healthy adults, and 29 tricky samples from patients with autoantibodies, with acute Epstein-Barr virus (EBV) or cytomegalovirus (CMV) infections, and from pregnant women. RESULTS: With the EIA, all but two of the early samples of the NE patients and all of the follow-up samples were positive for hantavirus IgG. All control samples were negative. The IgM EIA was positive in 42 of the 43 primary NE samples. Weak IgM EIA reactions were observed for some of the serum samples from patients with acute EBV and CMV infections. Optimal sensitivity and specificity values for the EIA were achieved when both the IgG and the IgM results were considered for the diagnosis of acute NE. All of the early NE samples reacted with the hantavirus nucleocapsid proteins in the IgG IB and all but one of these samples in the IgM IB. Cross reactions between the PUUV and the Hantaan antigens were very common. Several of the control samples did show borderline or positive bands, but these were mostly bands against only one hantavirus antigen in either the IgG or the IgM IB. The presence of at least three hantavirus bands (PUUV or HTNV) in the IgG and IgM assays was highly predictive of acute NE. CONCLUSION: Both assays were highly sensitive for the diagnosis of acute NE. However, the specificity of the IB IgM was only 76%. The specificity of both the IB and the EIA can be increased by modifications of the result interpretation.

Acute Disease↗
PubMed2001

Pilot study of the practical relevance of a one-step test for prostate-specific antigen in capillary blood to improve the acceptance rate in the early detection program of prostate carcinoma.

OBJECTIVE: Current studies have proven that early, organ-confined stages of prostate cancer can be diagnosed through screening based on PSA levels, thus reducing cancer mortality. Here we report about our experience using an innovative one-step test for PSA in capillary blood. METHODS: The incubation time for a 50 microl blood sample with the indicator strip is 12 minutes until the qualitative visual results (<4.0 ng/ml or > or = 4 ng/ml) appear. In cooperation with urologists and accompanied by an extensive information campaign, the one-step test was made available free of charge to all men between the ages of 45 and 75 in all 28 pharmacies of our city (100,000 inhabitants). RESULTS: The test's acceptance rate among the 2,119 participants between the ages of 45 and 75 years amounted to 13.0%. Fifteen percent of all the tests conducted showed a positive PSA result (> or = 4 ng/ml). Prostate carcinoma was histologically confirmed in 14 (0.66%) of the men, nine times in the early stage (T2) and five times in the clinical stage (T3), corresponding to an incidence of circa 650 cases per 100,000 men in the target age group. CONCLUSIONS: This newly developed PSA test system can enhance the acceptance rate and effectiveness of medical check-ups for prostate cancer, because it is easy-to-use, cost-effective and accurate (specificity 81.3%, sensitivity 91.1%). The test should be always conducted by an experienced physician or pharmacist. It is not a substitute for a regular physical examination (DRE, TRUS, biopsy...).

Aged↗
PubMed2001

In vitro generation of human CD86+ dendritic cells from CD34+ haematopoietic progenitors by PMA and in serum-free medium.

The cytokine requirements to differentiate CD34+ progenitor cells from different origins either cord blood (CB) or peripheral blood (PB) into dendritic cells (DC) are known to be different. In addition to DC, macrophages and neutrophils are generated. On the other hand, phorbol esters such as PMA induce primary human CD34+ bone marrow (BM) progenitor cells to differentiate into functional DC and no other lineages are generated. In addition, FCS is used as culture supplement in most of the protocols described which contains additional foreign antigens potentially skewing the resulting immune response. Therefore, we evaluated the ability to differentiate CB- and PB-CD34+ progenitor cells into DC with PMA and under serum-free conditions. In this study, we delineate the maturation of cultured human blood DC by analysis of expression co-stimulatory molecule B7-2 (CD86). Human mature DC with typical morphology and surface antigen phenotype (CD1a-, CD83+ and CD86+) were obtained from CB- and PB-CD34+ progenitor cells after 1 week of culture in serum-free medium upon stimulation with PMA alone. The same result was obtained from ex vivo-expanded BM-CD34+ cells. CD86+ yield was increased by PMA compared to cytokine cocktails (28.0% +/- 7.0 versus 15.3% +/- 5.6 for CB and 44.6% +/- 7.5 versus 28.1% +/- 7.5 for PB, respectively). CD86 was most up-regulated in the presence of the calcium ionophore ionomycin. However, the number of viable cells after differentiation was decreased by PMA plus ionomycin (P < 0.05) or plus TNF-alpha (P > 0.05) as compared with that in PMA alone. We conclude that PMA is a potent activator to differentiate human CD34+ cells into mature DC in serum-free medium. This may be used for in vitro studies of primed or genetically modified DC against infectious and tumour-associated antigens.

Antigen Presentation↗
PubMed2001

Dissection of RNA-mediated ryegrass mosaic virus resistance in fertile transgenic perennial ryegrass (Lolium perenne L.).

Ryegrass mosaic virus (RgMV) frequently reduces yield and persistence of perennial ryegrass. We introduced an untranslatable RgMV coat protein (RgMV-CP) gene into perennial ryegrass using particle bombardment to explore the potential of RNA-mediated virus resistance. Nine months after inoculation with the RgMV-Bulgaria strain, the most resistant transgenic line showed no immuno-detectable RgMV-CP in all replications of the primary transformant and a sexual progeny. A significant influence of the transgenic line, virus strain and the period after inoculation on the RgMV level was observed. Typical examples of recovery resistance from initially susceptible plants were not identified. Molecular analysis revealed RgMV resistance operates by targeted RNA degradation resulting in post-transcriptional transgene silencing (PTGS) along with inhibition of virus RNA replication and was not associated with a threshold of transgene expression. Suppression of PTGS by RgMV differed significantly in two progenies with identical RgMV-CP transgene integration and a similar RgMV-CP transgene methylation pattern, suggesting the presence of quantitative components controlling the stability of PTGS in perennial ryegrass. This study extends RNA-mediated virus resistance, post transcriptional gene silencing and crop improvement by genetic engineering to an agronomically important perennial monocot.

Capsid↗