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1.
Oxf Med Case Reports ; 2023(9): omad100, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37771681

ABSTRACT

We report a patient with a novel presentation of anti-neutrophil cytoplasmic antibody positive (ANCA+) vasculitis of the brain and oral mucosa. ANCA+ vasculitis of the brain is usually associated with pachymeningitis and hypophysitis, and there are no cases reported with simultaneous brain and oral mucosal involvement. A 35-year-old African Zambian man presented with headache and bleeding swollen gingiva. He was myeloperoxidase (MPO) antibody positive with cytoplasmic staining. His MRI showed stable small callosal, periventricular and subcortical white matter non-enhancing lesions, without change over 15 months-compatible with vasculitis. His gingival biopsy was consistent with vasculitis. His headache and oral lesions responded to oral corticosteroids and intravenous immunoglobulin which have induced clinical remission. Our patient expands the clinical syndrome of ANCA+ MPO+ C-type vasculitis of the central nervous system with headaches complicating cerebral vasculitis and oral mucosal involvement.

2.
Br J Oral Maxillofac Surg ; 59(6): 633-642, 2021 07.
Article in English | MEDLINE | ID: mdl-34016464

ABSTRACT

Surgical site infections are a complication of oral and maxillofacial procedures, with the potential for significant morbidity and mortality. Use of preoperative, perioperative, and postoperative antibiotic prophylaxis to reduce the incidence of surgical site infections must be balanced with considerations of a patients' risk of antibiotic-related adverse events. This review aimed to provide evidence-based recommendations for antibiotic prophylaxis. Searches were conducted using MEDLINE, the Cochrane Library, EMBASE, and PUBMED for maxillofacial procedures including: treatment of dental abscesses, extractions, implants, trauma, temporomandibular joints, orthognathics, malignant and benign tumour removal, and bone grafting, limited to articles published since 2000. A total of 98 out of 280 retrieved papers were included in the final analysis. Systematic reviews were assessed using AMSTAR criteria. Randomised controlled trials were assessed for bias using Cochrane Collaborative tools. The overall quality of evidence was assessed using GRADE. Prophylactic antibiotic use is recommended in surgical extractions of third molars, comminuted mandibular fractures, temporomandibular joint replacements, clean-contaminated tumour removal, and complex implants. Prophylactic antibiotic use is not routinely recommended in fractures of the upper or midface facial thirds. Further research is required to provide recommendations in orthognathic, cleft lip, palate, temporomandibular joint surgery, and maxillofacial surgical procedures in medically-compromised patients.


Subject(s)
Antibiotic Prophylaxis , Surgery, Oral , Anti-Bacterial Agents/therapeutic use , Humans , Molar, Third , Surgical Wound Infection/drug therapy , Surgical Wound Infection/prevention & control
3.
Br J Oral Maxillofac Surg ; 58(1): 85-88, 2020 01.
Article in English | MEDLINE | ID: mdl-31473041

ABSTRACT

We present a non-healing lesion on the gingivae attached to the mandible that mimicked periodontal disease, and was refractory to local debridement and oral hygiene measures. Biopsy examination showed a metastatic epithelioid haemangioendothelioma. This rare vascular tumour is considered to be malignant and management is controversial, owing to the paucity of published data. Treatment was provided in a multi-disciplinary setting as a result of established pulmonary and musculoskeletal metastases. The patient opted for conservative management and close surveillance of the lesion, which continues to remain stable at the time of writing, nearly two years after the initial assessment.


Subject(s)
Hemangioendothelioma, Epithelioid , Lung Neoplasms , Neoplasms, Second Primary , Biopsy , Humans , Lung
4.
Br J Oral Maxillofac Surg ; 56(10): 941-945, 2018 12.
Article in English | MEDLINE | ID: mdl-30415962

ABSTRACT

The aim of this study was to compare the failure rate of fixation of skeletal orthodontic anchorage plates (SAP) with two screws with that of three screws, and to find out if there is a relation between the number of screws used to fix the plates and the failure rate. We reviewed clinical records of 65 patients from five hospitals with 176 SAP, and took into account other factors that may have affected the failure. The overall failure rate was 15/176 (8.5%), and for with two-screw fixation it was 9/86 compared with 6/90 for those with three-screw fixation. Age, sex, and coexisting medical conditions did not affect the failure rate. There was a higher failure rate for those placed in the mandible (11/105) than for those placed in the maxilla (4/71). SAP provide a stable source of skeletal anchorage for orthodontic treatment. Our results show that those fixed with two screws may be marginally more likely to fail than those fixed with three, but further studies are needed to investigate the association between failure and the number of screws used.


Subject(s)
Bone Screws , Orthodontic Anchorage Procedures/methods , Adolescent , Adult , Bone Plates , Bone Screws/adverse effects , Child , Female , Humans , Male , Mandible/surgery , Maxilla/surgery , Middle Aged , Orthodontic Anchorage Procedures/adverse effects , Orthodontic Anchorage Procedures/instrumentation , Orthodontic Anchorage Procedures/statistics & numerical data , Prosthesis Failure , Retrospective Studies , Young Adult
5.
Aust Dent J ; 63 Suppl 1: S35-S47, 2018 03.
Article in English | MEDLINE | ID: mdl-29574816

ABSTRACT

The oral and maxillofacial region has a complex regional anatomy including hard and soft tissues. Trauma in this region may affect the airway, cause potentially life threatening bleeding and head injuries. The senses of olfaction, sight and hearing can also be disrupted as well as a profound psychological impact following disfigurement. This oral and maxillofacial trauma update provides information on demographics, incidence, pathophysiology, diagnosis, fracture patterns and management of facial trauma. It also discusses the role of new advancements in the management of facial trauma.


Subject(s)
Maxillofacial Injuries/therapy , Skull Fractures/therapy , Adolescent , Adult , Aged , Australia/epidemiology , Child , Female , Humans , Incidence , Male , Mandibular Fractures/diagnostic imaging , Mandibular Fractures/epidemiology , Mandibular Fractures/therapy , Maxillary Fractures/diagnostic imaging , Maxillary Fractures/epidemiology , Maxillary Fractures/therapy , Maxillofacial Injuries/diagnostic imaging , Maxillofacial Injuries/epidemiology , Middle Aged , Native Hawaiian or Other Pacific Islander , Orbit/diagnostic imaging , Risk-Taking , Skull Fractures/diagnostic imaging , Skull Fractures/epidemiology , Surgery, Oral , Tomography, X-Ray Computed , Young Adult , Zygoma/diagnostic imaging
6.
Aust Dent J ; 62(4): 464-470, 2017 Dec.
Article in English | MEDLINE | ID: mdl-28621799

ABSTRACT

BACKGROUND: Odontogenic infections are a common presentation to emergency departments of Australian hospitals. Due to the limited training in diagnosis and treatment of dental conditions, these patients can present a challenge for the medical practitioner. The objective of this study was to provide an evidence-based approach to the management of odontogenic infections in adults presenting to Royal Perth Hospital. METHODS: A literature search was conducted to identify evidence-based guidelines for the management of odontogenic infections in the tertiary hospital setting. Keywords 'dental', 'infections' and 'management' were used to search PubMed, DynaMed and Embase databases. RESULTS: Recommendations were drawn from existing literature including coroner reports with respect to clinical assessment, investigations, medical and surgical management, and postoperative care. A flow chart, incorporating these recommendations, was created to allow for appropriate disposition of patients presenting with odontogenic infections to Royal Perth Hospital. CONCLUSIONS: A clinical guideline is needed to appropriately manage patients presenting with odontogenic infections. We recommend the guideline be submitted to intradepartmental committees for assessment.


Subject(s)
Focal Infection, Dental/therapy , Practice Guidelines as Topic , Tooth Diseases/therapy , Adult , Emergency Service, Hospital , Evidence-Based Medicine , Humans , Practice Patterns, Dentists' , Tertiary Care Centers
7.
J Chem Phys ; 145(21): 211917, 2016 Dec 07.
Article in English | MEDLINE | ID: mdl-28799341

ABSTRACT

The interplay between polymers and inorganic minerals during the formation of solids is crucial for biomineralization and bio-inspired materials, and advanced material properties can be achieved with organic-inorganic composites. By studying the reaction mechanisms, basic questions on organic-inorganic interactions and their role during material formation can be answered, enabling more target-oriented strategies in future synthetic approaches. Here, we present a comprehensive study on the hydrolysis of iron(iii) in the presence of polyaspartic acid. For the basic investigation of the formation mechanism, a titration assay was used, complemented by microscopic techniques. The polymer is shown to promote precipitation in partly hydrolyzed reaction solutions at the very early stages of the reaction by facilitating iron(iii) hydrolysis. In unhydrolyzed solutions, no significant interactions between the polymer and the inorganic solutes can be observed. We demonstrate that the hydrolysis promotion by the polymer can be understood by facilitating oxolation in olation iron(iii) pre-nucleation clusters. We propose that the adsorption of olation pre-nucleation clusters on the polymer chains and the resulting loss in dynamics and increased proximity of the reactants is the key to this effect. The resulting composite material obtained from the hydrolysis in the presence of the polymer was investigated with additional analytical techniques, namely, scanning and transmission electron microscopies, light microscopy, atomic force microscopy, zeta potential measurements, dynamic light scattering, and thermogravimetric analyses. It consists of elastic, polydisperse nanospheres, ca. 50-200 nm in diameter, and aggregates thereof, exhibiting a high polymer and water content.

8.
Brain Struct Funct ; 217(3): 747-60, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22198594

ABSTRACT

While the functional correlates of spelling impairment have been rarely investigated, to our knowledge no study exists regarding the structural characteristics of spelling impairment and potential changes with interventions. Using diffusion tensor imaging at 3.0 T, we here therefore sought to investigate (a) differences between children with poor spelling abilities (training group and waiting group) and controls, and (b) the effects of a morpheme-based spelling intervention in children with poor spelling abilities on DTI parameters. A baseline comparison of white matter indices revealed significant differences between controls and spelling-impaired children, mainly located in the right hemisphere (superior corona radiata (SCR), posterior limb of internal capsule, superior longitudinal fasciculus). After 5 weeks of training, spelling ability improved in the training group, along with increases in fractional anisotropy and decreases of radial diffusivity in the right hemisphere compared to controls. In addition, significantly higher decreases of mean diffusivity in the right SCR for the spelling-impaired training group compared to the waiting group were observed. Our results suggest that spelling impairment is associated with differences in white-matter integrity in the right hemisphere. We also provide first indications that white matter changes occur during successful training, but this needs to be more specifically addressed in future research.


Subject(s)
Brain/pathology , Diffusion Tensor Imaging/methods , Language Development Disorders/pathology , Language Development Disorders/therapy , Language Therapy/methods , Nerve Fibers, Myelinated/pathology , Adolescent , Anisotropy , Child , Cohort Studies , Female , Germany , Humans , Male , Psychometrics , Treatment Outcome
9.
Rehabilitation (Stuttg) ; 45(6): 345-53, 2006 Dec.
Article in German | MEDLINE | ID: mdl-17123216

ABSTRACT

The need for standardized and unified performance capacity assessment in orthopedic rehabilitation has led to the attempt to use an existing standardized procedure. Graduated disease features have been defined which are relevant for work and their effects on performance capacity been formulated as rules. In this way so-called disease-conditioned performance capacities are obtained which help to identify problems in carrying out various activities. These activities can be directly assessed using tests. Appropriate tests are listed in a table.


Subject(s)
Disability Evaluation , Musculoskeletal Diseases/rehabilitation , Outcome Assessment, Health Care/standards , Rehabilitation, Vocational/standards , Germany , Humans , Joint Diseases/rehabilitation , Low Back Pain/rehabilitation , Musculoskeletal Diseases/psychology , Reference Standards , Sick Role , Social Medicine
10.
Biomed Tech (Berl) ; 47 Suppl 1 Pt 2: 851-3, 2002.
Article in English | MEDLINE | ID: mdl-12465322

ABSTRACT

This project shows the way vital parameters can be transmitted and visualized with no connecting cables necessary to the PDA. This was realized using a sensor developed with an integrated Bluetooth interface and a PDA, also equipped with Bluetooth. This radio connection can span up to 10 m, and parameters, such as pulse frequency, oxygen saturation in blood, ECG measurements and plethysmograms, can be transmitted. Using the software introduced in this work, the transmitted measurements can be displayed numerically or graphically on the PDA. The software simultaneously checks for any limits and sends a warning message if these limits are exceeded. All received data are additionally documented.


Subject(s)
Monitoring, Physiologic/instrumentation , Radio/instrumentation , Signal Processing, Computer-Assisted/instrumentation , User-Computer Interface , Computer Graphics , Data Display , Humans , Microcomputers , Software
11.
Genome Res ; 10(9): 1421-9, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10984460

ABSTRACT

The accurate mapping of clones derived from genomic regions containing complex arrangements of repeated elements presents special problems for DNA sequencers. Recent advances in the automation of optical mapping have enabled us to map a set of 16 BAC clones derived from the DAZ locus of the human Y chromosome long arm, a locus in which the entire DAZ gene as well as subsections within the gene copies have been duplicated. High-resolution optical mapping employing seven enzymes places these clones into two contigs representing four distinct copies of the DAZ gene and highlights a number of differences between individual copies of DAZ.


Subject(s)
Chromosome Mapping/methods , Chromosomes, Bacterial/genetics , RNA-Binding Proteins/genetics , Y Chromosome/genetics , Chromosome Mapping/instrumentation , Cloning, Molecular/methods , Contig Mapping , Deleted in Azoospermia 1 Protein , Deoxyribonucleases, Type II Site-Specific/analysis , Genetic Markers/genetics , Humans , Mutagenesis, Insertional , RNA-Binding Proteins/analysis , Restriction Mapping
12.
Handchir Mikrochir Plast Chir ; 32(1): 38-43, 2000 Jan.
Article in German | MEDLINE | ID: mdl-10763128

ABSTRACT

The goal of this ex-vivo study was a controlled macroscopical and microscopical comparison of the immediate effects of surgical lasers on dense collagenous tissues. The investigation of the exact denaturizing effects following tissue interaction between lasers and collagenous fibers are of importance for a better understanding of the observed and described healing process. Partial tenotomies were performed ex vivo on sixty tendons of the flexor digitorum profundus muscle of New Zealand White Rabbits using four surgical lasers (Holmium:YAG-, Erbium:YAG-, Neodym:YAG-, and CO2-Laser). The tendons were evaluated macroscopically, histologically and observations were made on the surgical handling of the lasers during the procedure. The choice of lasers allowed the comparison of a wide spectrum of wavelengths (gamma = 1.0 to 10.6 microns). In addition, beam delivery modalities were compared to each other (focus vs. contact). The pulse (frequency and power) was varied within each laser. Other parameters including focus size, absorption, dispersion, and thermal tissue conductivity were maintained constant in this test arrangement in order to allow a later comparison between the observed areas of denaturated collagen. The macroscopical and histological results showed great differences in the effects of the four lasers. Even within each single laser group, the results varied greatly with the choice of variable parameters. Holmium:YAG- and CO2-Laser can produce similar areas of collagen denaturation. When comparing specimens with similar areas of collagen denaturation induced by different laser types, different amounts of charring were observed. Erbium:YAG-Laser tenotomies showed generally inhomogeneous denaturation areas, while tenotomies with Neodym: YAG-Laser used in continuous mode resulted in significant charring and tissue retraction in the area of interaction. These observations help in defining the combination of parameters with which Holmium:YAG-, Erbium:YAG-, and CO2-Lasers can be used for transsection of dense collagenous tissues. In addition, these histological results as well as already published observations on healing patterns following laser surgery allow for the formulation of a hypothesis on the effects of laser in the wound healing process.


Subject(s)
Collagen/ultrastructure , Laser Therapy/instrumentation , Protein Denaturation/physiology , Tendons/surgery , Animals , Equipment Design , Rabbits , Tendons/pathology
13.
Eur J Biochem ; 264(1): 27-38, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10447670

ABSTRACT

We have identified two separate hemocyanin types (HtH1 and HtH2) in the European abalone Haliotis tuberculata. HtH1/HtH2 hybrid molecules were not found. By selective dissociation of HtH2 we isolated HtH1 which, as revealed by electron microscopy and SDS/PAGE, is present as didecamers of a approximately 400 kDa subunit. Immunologically, HtH1 and HtH2 correspond to keyhole limpet hemocyanin (KLH)1 and KLH2, respectively, the two well-studied hemocyanin types of the closely related marine gastropod Megathura crenulata. On the basis of limited proteolytic cleavage, two-dimensional immunoelectrophoresis, SDS/PAGE and N-terminal sequencing, we identified eight different 40-60 kDa functional units in HtH1, termed HtH1-a to HtH1-h, and determined their linear arrangement within the elongated subunit. From Haliotis mantle tissue, rich in hemocyanin-producing pore cells, we isolated mRNA and constructed a cDNA library. By expression screening with HtH-specific rabbit antibodies, a cDNA clone was isolated and sequenced which codes for the three C-terminal functional units f, g and h of HtH1. Their sequences were aligned to those available from other molluscs, notably to functional unit f and functional unit g from the cephalopod Octopus dofleini. HtH1-f, which is the first sequenced functional unit of type f from a gastropod hemocyanin, corresponds to functional unit f from Octopus. Also functional unit g from Haliotis and Octopus correspond to each other. HtH1-h is a gastropod hemocyanin functional unit type which is absent in cephalopods and has not been sequenced previously. It exhibits a unique tail extension of approximately 95 amino acids, which is lacking in functional units a to g and aligns with a published peptide sequence of 48 amino acids from functional unit h of Helix pomatia hemocyanin. The new Haliotis sequences are discussed with respect to their counterparts in Octopus, the 15 A three-dimensional reconstruction of the KLH1 didecamer from electron micrographs, and the recent 2.3 A X-ray structure of functional unit g from Octopus hemocyanin.


Subject(s)
Hemocyanins/analogs & derivatives , Mollusca/chemistry , Amino Acid Sequence , Animals , Cloning, Molecular , DNA, Complementary , Hemocyanins/chemistry , Hemocyanins/genetics , Microscopy, Electron , Molecular Sequence Data , Rabbits , Sequence Homology, Amino Acid
14.
Exp Cell Res ; 245(2): 272-81, 1998 Dec 15.
Article in English | MEDLINE | ID: mdl-9851867

ABSTRACT

Amphibian oocytes accumulate a large pool of mRNA molecules for future embryonic development. Due to their association with specific proteins the stored maternal RNAs are translationally repressed. The identification of these RNA-binding proteins and the characterization of their functional domains may contribute to the understanding of the translational repression mechanisms and the subsequent activation processes during early embryogenesis. Here we present the complete Pleurodeles cDNA sequence of a cytoplasmic protein which is present in oocytes, eggs, and very early cleavage stage embryos but undetectable in postcleavage embryo and adult tissues. The predicted molecular mass of the protein is 55 kDa and the apparent molecular mass as determined by SDS-PAGE, 68 kDa. The deduced amino acid sequence reveals proline- and serine-rich domains in the aminoterminal part as well as two RGG boxes which represent characteristic motifs of several RNA-binding proteins. No distinct homologies to the consensus RNA recognition motif were found. The 55-kDa protein was recovered in cytoplasmic ribonucleoprotein (RNP) particles containing poly(A)+ RNA. It was therefore termed RAP55 for mRNA-associated protein of 55 kDa. However, a direct interaction of RAP55 with mRNA could not be demonstrated by UV-crosslinking experiments, indicating that it is bound to mRNP complexes via protein-protein interactions. RAP55 is evolutionarily conserved since antibodies raised against a recombinant Pleurodeles RAP55 fragment recognize the protein from Pleurodeles and Xenopus. The expression pattern and intracellular distribution of RAP55 suggest that it is part of those mRNP particles which are translationally repressed during oogenesis and become activated upon progesterone-induced oocyte maturation.


Subject(s)
Egg Proteins , Pleurodeles/metabolism , RNA-Binding Proteins/genetics , RNA-Binding Proteins/metabolism , Xenopus laevis/metabolism , Amino Acid Sequence , Animals , Base Sequence , Blotting, Western , Chromatography, Affinity , Cloning, Molecular , Cytoplasm/metabolism , Female , Gene Expression Regulation, Developmental , Molecular Sequence Data , Molecular Weight , Oocytes/metabolism , Organ Specificity , Pleurodeles/genetics , Protein Biosynthesis , RNA-Binding Proteins/chemistry , RNA-Binding Proteins/isolation & purification , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Ribonucleases/metabolism , Ribonucleoproteins/chemistry , Ribonucleoproteins/metabolism , Xenopus laevis/embryology
15.
Spine (Phila Pa 1976) ; 23(11): 1215-9, 1998 Jun 01.
Article in English | MEDLINE | ID: mdl-9636974

ABSTRACT

STUDY DESIGN: A biomechanical study was conducted during a 3.5-day period to test for changes occurring in pullout strengths of cancellous screws inserted into human cadaveric vertebral bodies. OBJECTIVES: To quantify, within the testing time of 3.5 days, the possible changes to the mechanical properties of cadaveric vertebral bodies, resulting from structural degradation caused by postmortem, time-dependent, autolytic processes during mechanical testing of implant-bone biomechanics. SUMMARY OF BACKGROUND DATA: Biomechanical testing of whole spinal implants and analysis of the screw-bone interface of spinal implants is an area of clinical interest that frequently requires the use of cadaveric spine specimens. Changes in vertebral bone properties during the testing period may invalidate experimental results, but no data are available on degradation of bone during the testing period. METHODS: Anterior oblique cancellous screws were inserted into human vertebral bodies from which the ventral cortex had been removed. The pullout strength was measured at 0, 24, 60, and 84 hours after insertion. The tests were performed on 48 human vertebral bodies, which were stored by freezing to -23 C, thawed for testing, and kept at room temperature during the testing time for as long as 84 hours. RESULTS: The axial pullout strength showed no statistically significant change during 84 hours (P = 0.15). There were no significant differences attributable to vertebral level from T4 to L4, probably because the ventral cortices had been removed (P = 0.7). CONCLUSIONS: During 3.5 days, there were no changes in pullout strength of vertebral cancellous bone. In biomechanical studies during a maximum period of 3 days with a small number of cadaveric spines (e.g., four spine specimen) the time-dependent changes in pullout strength play a less significant role than do the interspine differences. Interspine differences should be regarded as an important factor to be considered in the design of biomechanical tests.


Subject(s)
Autolysis/physiopathology , Bone Screws , Lumbar Vertebrae/physiopathology , Lumbar Vertebrae/surgery , Biomechanical Phenomena , Cadaver , Follow-Up Studies , Humans , Middle Aged , Time Factors
16.
Biochim Biophys Acta ; 1368(2): 201-15, 1998 Jan 19.
Article in English | MEDLINE | ID: mdl-9459598

ABSTRACT

New vehicles for the non-invasive delivery of agents are introduced. These carriers can transport pharmacological agents, including large polypeptides, through the permeability barriers, such as the intact skin. This capability depends on the self-regulating carrier deformability which exceeds that of the related but not optimized lipid aggregates by several orders of magnitude. Conventional lipid suspensions, such as standard liposomes or mixed lipid micelles, do not mediate a systemic biological effect upon epicutaneous applications. In contrast to this, the properly devised adaptable carriers, when administered on the intact skin, transport therapeutic amounts of biogenic molecules into the body. This process can be nearly as efficient as an injection needle, as seen from the results of experiments in mice and humans with the insulin-carrying vesicles. The carrier-mediated transcutaneous insulin delivery is unlikely to involve shunts, lesions or other types of skin damage. Rather than this, insulin is inferred to be transported into the body between the intact skin cells with a bio-efficiency of at least 50% of the s.c. dose action.


Subject(s)
Insulin/administration & dosage , Liposomes/chemistry , Skin/metabolism , Administration, Cutaneous , Adult , Animals , Blood Glucose/analysis , C-Peptide/blood , Cholic Acid , Cholic Acids , Drug Carriers , Female , Humans , Insulin/blood , Insulin/pharmacokinetics , Mice , Mice, Inbred Strains , Micelles , Permeability , Phosphatidylcholines , Rats , Recombinant Proteins
17.
Int J Dev Biol ; 40(1): 239-44, 1996 Feb.
Article in English | MEDLINE | ID: mdl-8735934

ABSTRACT

Xenopus oocytes express a 165 kDa variant of DNA topoisomerase I (topo I) as opposed to the canonical 110 kDa form of somatic cells (Richard and Bogenhagen, Dev. Biol. 146: 4-11, 1991). By immunofluorescence microscopy using variant-specific antibodies we show that this high molecular weight form is associated with lampbrush chromosome loops and the inner regions of the amplified nucleoli. Inhibition of topo I-activity by either Camptothecin-treatment or microinjection of neutralizing antibodies resulted in loop retraction and the condensation of chromosomes and amplified nucleoli. These data indicate that the oocyte-specific 165 kDa form of topo I is involved in transcriptional processes mediated by RNA polymerase I and II and is therefore functionally equivalent to the somatic cell 110 kDa counterpart.


Subject(s)
DNA Topoisomerases, Type I/metabolism , Oocytes/enzymology , Xenopus laevis/metabolism , Animals , Cell Nucleolus/enzymology , Chromosomes/enzymology , DNA Topoisomerases, Type I/chemistry , DNA Topoisomerases, Type I/immunology , Female , Microscopy, Fluorescence , Molecular Weight
18.
Chromosoma ; 104(5): 358-66, 1996.
Article in English | MEDLINE | ID: mdl-8575248

ABSTRACT

By immunizing Balb/c mice with oocyte nuclei of Pleurodeles waltl we obtained a monoclonal antibody, mAb 4A6, that labels distinct globular domains of the lampbrush chromosomal axes of Pleurodeles. These domains are found at corresponding sites of homologous chromosomes, often at telomeric and putative centromeric regions, and appear to be devoid of DNA. Because of these characteristic features it is most likely that the mAb 4A6-positive domains correspond to the central part of the "axial granules" of urodelan lampbrush chromosomes. In immunoblotting analyses mAb 4A6 reacts with a nuclear antigen of approximately Mr 180000 and a structurally nonrelated cytoplasmic protein of Mr 98000, which was not characterized any further. Comparative immunofluorescence and immunoblotting studies with mAb 4A6 and an antiserum against DNA topoisomerase II (topo II) as well as immunodepletion experiments demonstrated that the nuclear 4A6 antigen is topo II. Our results indicate that topo II is not a constituent of a continuous, loop-anchoring scaffold in lampbrush chromosomes of Pleurodeles but, rather, is restricted to the axial granules.


Subject(s)
Antibodies, Monoclonal , Chromosomes/enzymology , DNA Topoisomerases, Type II/analysis , Animals , Antigens, Nuclear , Chromatin/chemistry , Chromosomes/ultrastructure , DNA Topoisomerases, Type II/chemistry , DNA Topoisomerases, Type II/immunology , Female , Mice , Mice, Inbred BALB C , Microscopy, Fluorescence , Microscopy, Immunoelectron , Molecular Weight , Nuclear Proteins/analysis , Nuclear Proteins/chemistry , Oocytes , Pleurodeles , Proteins/analysis , Proteins/chemistry , Xenopus laevis
19.
Z Orthop Ihre Grenzgeb ; 128(1): 100-7, 1990.
Article in German | MEDLINE | ID: mdl-2138379

ABSTRACT

For quantified evaluation of the primary stability of cementless femoral stem prostheses the operative faults: too low sized stem, distally short-lined anchoring with proximally surpassing stem and fissure or fracture of the femur shaft were simulated in autoptical test series. By inductive displacement transducers the micromotion between stem and proximal bone layer were measured in medio-lateral and ventro-dorsal direction under static load conditions before and after a dynamic loading of 50,000 cycles. The underdimensioned stem showed its instable anchoring by obviously increased micromotions in all measure plains. The proximally excelling only distally anchored prosthesis demonstrated immense amounts of motion. The fissure doesn't seem to decrease the primary stability of the stems too much. These results of the autoptical test series can only be directly transferred to the conditions of the first weeks after implantation, because the influence of later bone integration could not be considered.


Subject(s)
Hip Prosthesis , Postoperative Complications/physiopathology , Biomechanical Phenomena , Femur/physiopathology , Follow-Up Studies , Humans , Prosthesis Design , Prosthesis Failure
20.
Biomed Tech (Berl) ; 35(1-2): 15-25, 1990.
Article in German | MEDLINE | ID: mdl-2317541

ABSTRACT

A hip joint simulator was developed to analyse the mechanism of loosening of cementless artificial hip cups. The machine induces vibrating motions and asymmetrical tilt shock loadings of the artificial cup. On measuring the primary stability of threaded cups, the simulation tests performed on pelvis substitute models, and animal and human acetabula failed to show any loosening of threaded cups fixed in place with a screw-in torque of more than 10 Nm. Instable cups became loose all the sooner, the lower the preload between the cup and femoral head. This demonstrates the importance of both the screw-in torque of the cup and the training status of the periarticular muscles.


Subject(s)
Hip Prosthesis , Biomechanical Phenomena , Humans , Prosthesis Design , Prosthesis Failure , Risk Factors
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