Biomedical subjects

Martin Jung

Publications and source records attributed to Martin Jung.

At least 19 recordsLinked to original sources

PubMed2006

Dens invaginatus type II: case report with 2-year radiographic follow-up.

Dens invaginatus is a malformation of teeth probably resulting from an infolding of the dental papilla during tooth development. Clinically, it is frequently characterized by unusual crown morphology. It is common to see peg- or barrel-shaped teeth. The present case describes dens invaginatus in a lateral maxillary incisor (Oehler type II) with a barrel-shaped crown of a 12-year-old female patient; endodontic treatment and adhesive restoration were performed. After two years the tooth showed no signs of pathosis.

Child↗

PubMed2006

An in vivo study of a growth-factor enhanced, cell free, two-layered collagen-tricalcium phosphate in deep osteochondral defects.

Focal osteochondral defects are still a challenging problem in joint surgery. We have developed a two-layered implant consisting of a basal porous beta-tricalcium phosphate (TCP) for bone reconstruction and a superficial fibrous collagen type I/III layer for cartilage regeneration. Fifty-four osteochondral defects in the trochlear groove of 27 Göttinger Minipigs were created and either left untreated, treated with the implant alone, or the implant augmented with an additional growth factor mixture, which was assumed to stimulate cell and tissue differentiation. Follow-up was 6, 12 and 52 weeks with n=6 for each group. The repair tissue was evaluated for its gross appearance and biomechanical properties. Histological sections were semi-quantitatively scored for their histomorphological structure. Treatment with the two-layered implant improved defect filling and subchondral bone repair at 6 and 12 weeks follow-up. The TCP was replaced by cancellous bone at 52 weeks. Cartilage repair tissue mainly consisted of fibrocartilage and showed a moderate cell density up to the joint surface. Growth factor treatment improved the mechanical and histomorphological properties of the cartilage repair tissue at 12, but not at 52 weeks postoperatively. In conclusion, the two-layered collagen-TCP implant augmented with chondroinductive growth factors seems a promising new option for the treatment of deep osteochondral defects in joint surgery.

Animals↗

PubMed2006

Osseointegration and mechanical stability of pyrocarbon and titanium hand implants in a load-bearing in vivo model for small joint arthroplasty.

PURPOSE: To test the mechanical stability and histologic osseointegration under load-bearing conditions of 2 different materials, pyrocarbon (Py) and titanium (Ti), in a rabbit model. METHODS: Proximal interphalangeal implants (9 Ti, 8 Py) were placed into rabbit knees and the animals were killed after 3 months. Subsidence was assessed by monthly x-rays. Mechanical stability was measured with a nondestructive pullout test. Implant osseointegration was evaluated by an analysis of the relative implant-calcified bone contact surface on microradiographs and by a histomorphometric analysis of the percentage of bone and connective tissue contact with the implant surface. Histologic examination included assessment of bone apposition on the basis of fluorochromes. RESULTS: Subsidence was found in all 8 Py implants but in none of the Ti group. All 9 Ti implants were mechanically stable; all 8 Py implants were loose. A significantly higher implant-bone contact was found for the Ti group compared with the Py group. Bone apposition increased with time and was highest for the Ti implants 6 weeks after implantation. CONCLUSIONS: In the rabbit model osseointegration of implants was highly dependent on the material. A reliable osseointegration was found for Ti implants. For Py implants no osseointegration or implant stability was achieved. For use of small joints of the hand we therefore recommend Ti-based implants.

Animals↗

PubMed2006

Genomic and expression analysis of the 3q25-q26 amplification unit reveals TLOC1/SEC62 as a probable target gene in prostate cancer.

Gain at chromosome 3q25-q26 has been reported to commonly occur in prostate cancer. To map the 3q25-q26 amplification unit and to identify the candidate genes of amplification, we did fluorescence in situ hybridization and quantitative real-time PCR for gene copy number and mRNA expression measurements in prostate cancer cell lines and prostate cancer samples from radical prostatectomy specimens. The minimal overlapping region of DNA copy number gains in the cell lines could be narrowed down to 700 kb at 3q26.2. Of all positional and functional candidates in this region, the gene TLOC1/SEC62 revealed the highest frequency (50%) of copy number gains in the prostate cancer samples and was found to be up-regulated at the mRNA level in all samples analyzed. TLOC1/Sec62 protein was also shown to be overexpressed by Western blot analysis. Intriguingly, the TLOC1/SEC62 gene copy number was increased in prostate tumors from patients who had a lower risk of and a longer time to progression following radical prostatectomy. These findings make TLOC1/SEC62 the best candidate within the 3q amplification unit in prostate cancer. TLOC1/Sec62 protein is a component of the endoplasmic reticulum protein translocation machinery, whose function during prostate carcinogenesis remains to be determined.

Cell Line, Tumor↗

PubMed2005

Hungarian population data of four X-linked markers: DXS8378, DXS7132, HPRTB, and DXS7423.

DXS8378, DXS7132, HPRTB, and DXS7423 microsatellite markers located in four different X-chromosomal linkage groups were studied in the Hungarian population. After genotyping unrelated men (219) and women (165), forensic efficiency parameters showing that the four X-linked short tandem repeats are informative for forensic applications were calculated. With fragment and sequence analysis, one microvariant allele (11.2) was identified in the HPRTB locus. A deviation from the Hardy-Weinberg equilibrium could not be detected. Investigations of 96 father-child meioses revealed one mutation in the DXS7132 locus. For comparison of 22 different populations, G-tests were carried out.

Chromosomes, Human, X↗

PubMed2005

Approaches to the isolation and characterization of molecular chaperones.

Molecular chaperones are integral components of the cellular machinery involved in ensuring correct protein folding and the continued maintenance of protein structure. An understanding of these ubiquitous molecules is key to finding cures to protein misfolding diseases such as Alzheimer's and Creutzfeldt-Jacob diseases. In addition, further understanding of chaperones will enhance our comprehension of the way the body copes with the environmental stresses that humans encounter daily. Our laboratory and our collaborators specialize in the production and characterization of chaperones from a wide variety of sources in order to gain a fuller understanding of how chaperones function in the cell. In this review, we primarily use the Hsp70/Hsp40 chaperone pair as an example to discuss recent advances in technology and reductions in cost that lend themselves to chaperone purification from both native and recombinant sources. Common assays to assess purified chaperone activity are also discussed.

Adenosine Triphosphatases↗

PubMed2005

Molecular characterization of spontaneous and growth-factor-augmented chondrogenesis in periosteum-bone tissue transferred into a joint.

Multilineage potential of progenitor cells from periosteum is well established, but conditions for differentiation within their native niche are unclear. We evaluated at cellular and molecular levels whether chondrogenesis of periosteal progenitor cells is promoted spontaneously or by growth-factor mixture (GFM) application when transferring periosteum-bone cylinders into cartilage defects. Osteochondral defects in the patellar groove of minipigs were filled with periosteum-bone cylinders and randomly supplemented with GFM. Neochondrogenesis was characterized by histology, immunohistology, and quantitative gene expression analysis. According to morphology and glycosaminoglycan accumulation, spontaneous neocartilage formation occurred in the cambium layer already at 6 weeks, increased after 12 weeks, but declined until 52 weeks, independent of GFM. Multiple cartilage differentiation markers were induced after transfer. Expression of aggrecan, COMP, decorin, and Col10a1 increased significantly within 52 weeks. Sox 9 and Col2a1 mRNA levels were elevated at 6 versus 52 weeks in the GFM group and resulted in higher collagen type II protein accumulation. Neochondrogenesis was promoted in lower periosteum layers by transfer of periosteum-bone plugs into a joint, and collagen type II protein deposition was enhanced by GFM. The final tissue subsumed typical features of periosteum and fibrocartilage but lacked an intact tide mark and features of hyaline cartilage desired for cartilage repair.

Animals↗

PubMed2005

Characterization of the human GARP (Golgi associated retrograde protein) complex.

The Golgi associated retrograde protein complex (GARP) or Vps fifty-three (VFT) complex is part of cellular inter-compartmental transport systems. Here we report the identification of the VFT tethering factor complex and its interactions in mammalian cells. Subcellular fractionation shows that human Vps proteins are found in the smooth membrane/Golgi fraction but not in the cytosol. Immunostaining of human Vps proteins displays a vesicular distribution most concentrated at the perinuclear envelope. Co-staining experiments with endosomal markers imply an endosomal origin of these vesicles. Significant accumulation of VFT complex positive endosomes is found in the vicinity of the Trans Golgi Network area. This is in accordance with a putative role in Golgi associated transport processes. In Saccharomyces cerevisiae, GARP is the main effector of the small GTPase Ypt6p and interacts with the SNARE Tlg1p to facilitate membrane fusion. Accordingly, the human homologue of Ypt6p, Rab6, specifically binds hVps52. In human cells, the "orphan" SNARE Syntaxin 10 is the genuine binding partner of GARP mediated by hVps52. This reveals a previously unknown function of human Syntaxin 10 in membrane docking and fusion events at the Golgi. Taken together, GARP shows significant conservation between various species but diversification and specialization result in important differences in human cells.

Animals↗

PubMed2005

Lunate resection and vascularized Os pisiform transfer in Kienböck's Disease: an average of 10 years of follow-up study after Saffar's procedure.

PURPOSE: To investigate the long-term results of lunate replacement by vascularized bone transfer in advanced Kienböck's disease. METHODS: Twenty-one patients were reviewed (mean follow-up period +/- SD, 9.9 +/- 3.5 y) to analyze results after lunate replacement by vascularized pisiform transposition (Saffar's procedure) for Lichtman stages III and IV. RESULTS: Pain was improved in 16 of 21 patients but range of motion did not improve after surgery. Range of motion was reduced to 68% and grip power to 80% of that of the opposite hand. At follow-up evaluation the mean score on the Disabilities of the Arm, Shoulder, and Hand Questionnaire was 22.3 +/- 17.9 and the mean Cooney score was 75.4 +/- 13.2. Radiologically, Lichtman stage persisted in 8, improved in 1, progressed in 8, and could not be evaluated in 3 patients. Two patients had radiologic signs of arthritis before surgery. At follow-up examination osteoarthritis was found in 50% of patients. The majority of degenerative changes were associated with carpal collapse. CONCLUSIONS: The replacement of the lunate by vascularized pisiform transposition maintained preoperative ranges of motion. At follow-up examination both patient satisfaction and wrist function were high. In the long term, however, Saffar's procedure can restore alignment of the carpus only partly and also results in osteoarthritis in half of all patients.

Adult↗

PubMed2005

Vascularized os pisiform for reinforcement of the lunate in Kienböck's Disease: an average of 12 years of follow-up study.

PURPOSE: Little is known about the long-term results of vascularized bone transplantation for Kienböck's disease. This retrospective study investigated the long-term results of vascularized pisiform transfer. METHODS: We reviewed 23 patients to analyze results after vascularized pisiform transposition to a cored-out lunate for Lichtman stages II and III. Patients with ulnar-minus variance received additional radial shortening. RESULTS: Pain improved in 20 of 23 patients. Range of motion increased significantly relative to preoperative values but was only 80% that of opposite side. Grip power was 84% of the contralateral hand. At follow-up evaluation the mean Disabilities of the Arm, Shoulder, and Hand questionnaire score was 15.3 +/- 17.9 and the mean Cooney score was 82.4 +/- 10.0. Radiologically, out of 20 patients with preoperative x-rays Lichtman stage was unchanged in 11, improved in 3, and progressed in 6 patients. No patient showed radiologic signs of arthritis before surgery. At follow-up evaluation osteoarthritis was found in 7 of 22 patients. The majority of degenerative changes were of low grade and were seen at the radiocarpal joint. CONCLUSIONS: The results show high patient satisfaction and good function after vascularized bone transplantation for Kienböck's disease. In the long term vascularized pisiform transfer prevented lunate collapse in 16 of 22 patients.

Adolescent↗

PubMed2005

Occurrence of carpal osteoarthritis after treatment of scaphoid nonunion with bone graft and herbert screw: a long-term follow-up study.

PURPOSE: To determine the occurrence, progression, and clinical results of osteoarthritis (OA) after bone grafting and Herbert screw fixation for scaphoid nonunion. METHODS: Fifty patients were reviewed (mean follow-up period, 12.0 +/- 1.6 y) to analyze degenerative changes of the wrist after use of Herbert screws for scaphoid nonunion. RESULTS: Radiologic signs of OA were observed in 15 of 50 patients before surgery and in 23 of 50 after 10 years or more. The majority of degenerative changes were low grade. No OA at follow-up evaluation was seen in 27 of 35 patients with no preoperative degenerative changes. In 6 of 8 patients with OA its occurrence was either subsequent to concomitant injury, occurred after incorrect scaphoid reconstruction, or was caused by persistent nonunion. Of 15 wrists with OA at the time of surgery 9 remained unchanged and 6 increased in severity. Healing of nonunion was achieved in 42 of 50. Range of motion, however, was reduced to 88% of that of the opposite hand. At follow-up evaluation the mean Disabilities of the Arm, Shoulder, and Hand score was 9 +/- 13 and the mean Cooney score was 80 +/- 10. CONCLUSIONS: The results show high patient satisfaction and good function after healing of scaphoid nonunion. In the long term correct anatomic reconstruction of the nonarthritic carpus with a Herbert screw prevents onset of OA in most patients.

Adolescent↗

PubMed2005

Quality of bristle end-rounding on replaceable heads of powered toothbrushes.

OBJECTIVES: The aim of this study was to evaluate the geometry and the quality of bristle tip-rounding using 14 different heads from powered toothbrushes. MATERIAL AND METHODS: Six powered toothbrushes for children and eight for juveniles and adults were included. Five replaceable heads of each product were randomly selected. Of each sample, 35 bristles were used for examination. This resulted in 175 bristles from each product being evaluated. The quality of end-rounding was assessed by scanning electron microscopy at an original magnification x 80 in two categories of acceptable and five categories of unacceptable rounding according to Silverstone & Featherstone (1988). RESULTS: The portion of acceptable end-rounding varied strongly between the products (18.9-94.3%). There were significant differences regarding the products for children (p<0.001) and for adults (p<0.001) with respect to end-rounding quality. Only one product achieved more than 90% and eight products had between 68% and 86% acceptable end-rounding. Two products for children and one for adults had less than 25% acceptable end-rounding. CONCLUSION: A high standard of bristle tip-rounding is an important feature with respect to the safety of powered toothbrushes. Those products with a greater portion of unacceptably rounded bristles might cause more harm to oral soft tissues during use. The end-rounding quality of some of the products should be improved.

Adult↗

PubMed2004

Retention of structure in microemulsion polymerization: formation of nanolatices.

Polymerization of styrene-in-water microemulsions by photoinitiation using the initiator 2,2'-dimethoxy-2-phenyl acetophenone (DMPA) produces small nanolatices of the same size as the parent microemulsion (radius = 24-31 angstroms). This behavior is distinct from previously applied methods where significant particle growth accompanies the polymerization reaction. NMR measurements confirmed that polymerization is complete in under an hour and small-angle neutron scattering established the microemulsion structure before and after polymerization. The approach may be of more general application where retention of structure is sought in microemulsion-based polymer templating procedures.

Journal Article↗

PubMed2004

Does psychiatric comorbidity in alcohol-dependent patients affect treatment outcome?

Comorbidity in alcohol research refers to the presence of alcohol dependency and another major psychiatric disorder. The existence of additional disorders may have consequences for treatment planning and success. The aims of this paper are therefore: 1) to give an overview on prevalence rates in studies with representative cohorts and hospital-based samples; 2) to report results on gender differences and 3) to determine the impact of comorbidity on treatment outcome. Comorbidity was examined with the Composite International Diagnostic Interview (CIDI) in N = 118 (61 male and 57 female) alcohol-dependent patients who were socially well integrated. Results show that 65% of the female patients but only 28% of the male patients had a lifetime history of additional psychiatric disorders. Significantly more phobic/anxiety disorders, mood disorders occur in female patients. One year after inpatient treatment, overall 39% had suffered a relapse. More detailed analysis revealed that 55% of the non-comorbid but only 28% of the comorbid women suffered a relapse, thus contradicting our initial hypothesis that comorbid patients have a poorer prognosis with regard to their alcohol dependence. Male comorbid (40.9%) and non-comorbid (35.3%) patients showed no significant differences regarding relapse rates.

Alcoholism↗

PubMed2004

Effects of local application of growth and differentiation factor-5 (GDF-5) in a full-thickness cartilage defect model.

Our purpose in this study was to investigate the effects of growth and differentiation factor-5 (GDF-5) on cartilage and subchondral bone in a rabbit model harboring an osteochondral defect for a period of 6 months. Absorbable composites were implanted in adult rabbits (18 controls, 18 animals with collagen-I matrix, and 18 animals with matrix plus GDF-5). After 4, 8, or 24 weeks the specimens were studied by histology, microcomputed tomography (microCT) and flow-cytometric analysis (FACS). Implantation of GDF-5 resulted in an improved histological appearance. This was the result of significantly improved defect filling at 4 and 8 weeks. At 24 weeks, however, there was no difference between the groups. The histological examination disclosed a predominance of fibrocartilage, and remodeled subchondral bone was also observed. MicroCT documented normal bone density in all groups, excluding subchondral sclerosis. At 24 weeks, FACS analysis revealed high apoptotic activity in the GDF-5-treated group. As far as we are aware, this is the first report of the effects of GDF-5 in a full-thickness cartilage defect model. We assume that recombinant GDF-5 contained on the carrier is probably able to accelerate the regeneration of the osteochondral defect owing to its availability. However, control of the protein delivery may require further investigation.

Animals↗

PubMed2004

Protein transport into canine pancreatic microsomes: a quantitative approach.

Transport of presecretory proteins into the mammalian rough endoplasmic reticulum involves a protein translocase that comprises the integral membrane proteins Sec61alphap, Sec61betap, and Sec61gammap as core components. Electron microscopic analysis of protein translocase in rough microsomal membranes suggested that between three and four heterotrimeric Sec61p complexes form the central unit of protein translocase. Here we analyzed the stoichiometry of heterotrimeric Sec61p complexes present in cotranslationally active protein translocases of canine pancreatic microsomes and various other lumenal and membrane components believed to be subunits of protein translocase and to be involved in covalent modifications. Based on these numbers, the capacity for cotranslational transport was estimated for the endoplasmic reticulum of the human pancreas.

Animals↗

PubMed2004

Characterization of pancreatic ERj3p, a homolog of yeast DnaJ-like protein Scj1p.

We have previously identified in the human EST sequence data base four overlapping clones that could be aligned with both a predicted protein sequence, deduced from the C. elegans genomic sequence, and partial amino acid sequences, obtained for a protein from canine pancreatic microsomes. We suggested that these proteins are homologs of yeast microsomal and DnaJ-like protein Scj1p and termed them ERj3p. Here we verified the predicted protein sequence of human ERj3p by sequence analysis of the corresponding cDNA. Multiple alignment of related sequences identified these proteins as true homologs of yeast Scj1p. Biochemical analysis of the canine protein characterized ERj3p as a soluble glycoprotein of the pancreatic endoplasmic reticulum. This pancreatic DnaJ-like protein was shown to interact with lumenal DnaK-like proteins, such as BiP. Furthermore, we found that ERj3p interacts with SDF2L1 protein that may be involved in protein O-glycosylation. We propose that ERj3p represents a cochaperone of DnaK-like chaperones of the mammalian endoplasmic reticulum and is involved in folding and maturation of newly synthesized proteins.

Amino Acid Sequence↗

PubMed2003

The Sec61p complex is a dynamic precursor activated channel.

Previous studies have shown that the rough endoplasmic reticulum (ER) contains nascent precursor polypeptide gated channels. Circumstantial evidence suggests that these channels are formed by the Sec61p complex. We reconstituted the purified Sec61p complex in a lipid bilayer and characterized its dynamics and regulation. The Sec61p complex is sufficient to form the precursor polypeptide activated channel under co- and posttranslational transport conditions. Activity of the Sec61p channel in both transport modes is induced by direct interaction with precursor protein. The Sec61p complex comprises a highly dynamic pore covering conductances corresponding to channel openings from approximately 6 to 60 A. Its properties are indistinguishable from those we observed with native ER channels, directly demonstrating that these channels are formed by the Sec61p complex.

ADP Ribose Transferases↗