Dimethyloxalylglycine stabilizes HIF-1α in cultured human endothelial cells and increases random-pattern skin flap survival in vivo

The goal of this study was to evaluate in vitro and in vivo the effects of up-regulation of the proangiogenic hypoxia inducible factor (HIF)-1α induced by dimethyloxalylglycine on endothelial cell cultures and on skin flap survival.

Evaluation of late results in breast reconstruction by latissimus dorsi flap and prosthesis implantation

BACKGROUND: Breast reconstruction by latissimus dorsi myocutaneous flap in combination with a prosthesis is a widely used, well-established procedure. Short- and medium-term evaluation after this procedure is well described in the literature, but there have been no evaluations of the late course (over 10 years) published until now. METHODS: In a retrospective study, 68 patients operated on by means of this technique at the authors' institution from 1981 to 1993 resulting in a minimal follow-up of 10 years were included. Patients were invited to an interrogation, clinical examination, and photographic documentation (n = 51). Incidence of late flap or prosthesis-related complications, number of and indications for corrective procedures, and the correlation of the patients' subjective judgment and objective results in the late course have been the main interest of the authors' survey. RESULTS: The authors found that 50 percent of the patients needed a late reoperation for change or removal of the prosthesis. Seven (10 percent) of 68 patients needed a definitive removal of the implant in the late course. Assessment of the photographic documentation of the late result by four nonprofessionals showed that the objective aesthetic results of a considerable number of the authors' reconstructions were not sufficient. CONCLUSION: The procedure combines two basic techniques of reconstructive surgery, the soft-tissue restoration by a pedicled flap as the autologous reconstructive component and the volume reconstruction by prosthesis. Therefore, these patients are subject to a cumulation of the basic morbidity of the two techniques. The authors conclude that the indication for this procedure should be restricted to patients not qualifying for "pure" reconstructive techniques.

Trypanosoma congolense procyclins: unmasking cryptic major surface glycoproteins in procyclic forms

In the tsetse fly, the protozoan parasite Trypanosoma congolense is covered by a dense layer of glycosylphosphatidylinositol (GPI)-anchored molecules. These include a protease-resistant surface molecule (PRS), which is expressed by procyclic forms early in infection, and a glutamic acid- and alanine-rich protein (GARP), which appears at later stages. Since neither of these surface antigens is expressed at intermediate stages, we investigated whether a GPI-anchored protein of 50 to 58 kDa, previously detected in procyclic culture forms, might constitute the coat of these parasites. We therefore partially purified the protein from T. congolense Kilifi procyclic forms, obtained an N-terminal amino acid sequence, and identified its gene. Detailed analyses showed that the mature protein consists almost exclusively of 13 heptapeptide repeats (EPGENGT). The protein is densely N glycosylated, with up to 13 high-mannose oligosaccharides ranging from Man(5)GlcNAc(2) to Man(9)GlcNAc(2) linked to the peptide repeats. The lipid moiety of the glycosylphosphatidylinositol is composed of sn-1-stearoyl-2-lyso-glycerol-3-HPO(4)-1-(2-O-acyl)-d-myo-inositol. Heavily glycosylated proteins with similar repeats were subsequently identified in T. congolense Savannah procyclic forms. Collectively, this group of proteins was named T. congolense procyclins to reflect their relationship to the EP and GPEET procyclins of T. brucei. Using an antiserum raised against the EPGENGT repeat, we show that T. congolense procyclins are expressed continuously in the fly midgut and thus form the surface coat of cells that are negative for both PRS and GARP.

Mandibular reconstruction using a combination graft of rhBMP-2 with bone marrow cells expanded in vitro

BACKGROUND: The aim of this study was to evaluate the efficacy of a combination graft, using recombinant human bone morphogenetic protein-2 (rhBMP-2) and culture-expanded cells derived from bone marrow, for bone regeneration in a nonhuman primate mandible. METHODS: Five Japanese monkeys were used. Three milliliters of bone marrow was obtained from the tibia and plated into culture flasks. Adherent cells were cultured until near confluence; then, the proliferated cells were transferred to a three-dimensional culture system using collagen beads as the cell carrier. The medium was supplemented with ascorbic acid, beta-glycerophosphate, and dexamethasone to promote osteoblastic differentiation. After further proliferation on beads, the cells were mixed with a collagen sponge that was impregnated with rhBMP-2 and grafted into surgically created segmental bone defects of the mandibles. Three animals received this treatment, and either culture-expanded cells alone or collagen beads without cells were implanted into the remaining two monkeys as controls. The animals were killed 24 weeks after surgery, and the results were assessed by radiographic and histologic evaluation. RESULTS: The combination graft of culture-expanded bone marrow cells with rhBMP-2 in a collagen sponge regenerated the mandibular bone completely. By contrast, the graft of culture-expanded cells alone resulted in only a small amount of bone formation, and the implantation of collagen beads alone led to no bone formation. CONCLUSION: The combination graft of rhBMP-2 and culture-expanded cells, which requires only a small amount of bone marrow, is a reliable method for the reconstruction of segmental bone defects of the mandible.

Displaced premolars in panoramic radiography: fact or fallacy?

OBJECTIVE: To test the null hypothesis that there is no difference between premolar position visualized on panoramic radiographs (PRs) and lateral headfilms (LHs). MATERIALS AND METHODS: The prevalence of differences in the direction of crown angulation between PR and LH was assessed. Furthermore, brass wire markers with different sagittal and transverse angulations were placed in a dry skull. With the markers in place, LHs and PRs were taken. RESULTS: A difference in the direction of crown angulation of unerupted second premolars between PR and LH occurred in 19.5% of patients. The reason for the angulation differences is a buccolingual orientation of the tooth, which appears as a mesiodistal angulation on the PR. CONCLUSION: The null hypothesis was rejected since in one-fifth of the patients premolar projection differs between the panoramic radiograph and the lateral headfilm.

Assessment of vertical facial and dentoalveolar changes using panoramic radiography

The purpose of the study was to analyse longitudinal vertical facial and dentoalveolar changes using panoramic radiographs (PRs) and to compare the results with measurements on lateral cephalometric radiographs (LCRs) in order to determine whether, under certain circumstances, the radiation dose for a patient may be reduced by taking only a PR instead of a PR and a LCR. Pre- and post-treatment PRs and LCRs of 30 (15 females and 15 males) orthodontically treated adolescents (mean age pre-treatment 10.9 years, post-treatment 13.4 years) were analysed using Pearson's correlation coefficients and gender differences using Fisher's z-transformation. The results revealed that most variables exhibited larger absolute values on PRs than on LCRs. Comparison of dentoskeletal morphology between the LCRs and the PRs revealed moderate to high, mostly statistically significant, interrelations both before and after orthodontic treatment. The lowest correlations were found for the maxillary jaw base angle (NL/H; r= 0.35***) and the highest for the gonial angle (ML/RL; r = 0.90***). However, when assessing the combined growth and treatment changes from before to after treatment, only weak to moderate, not statistically significant, interrelations were found between LCRs and PRs. Anterior face height (AFH; r = 0.43***), the mandibular plane angle (ML/H; r = 0.06*), and the distance of the incisal tip of the most extruded mandibular incisor to the ML-line (ii-ML; r = -0.21*) were the only statistically significant parameters. The average group differences for growth and treatment changes, however, were small for most parameters. Analysis of vertical facial and dentoalveolar parameters on PRs delivers a moderate approximation to the situation depicted on LCRs. However, PRs cannot be recommended for the analysis of individual longitudinal changes in vertical facial and dentoalveolar parameters.

Platelets increase while serum reduces the differentiation and activity of osteoclasts in vitro

Platelets modulate formation of osteoclasts and osteoblasts, but research with different preparations of platelets remains inconclusive. Here, we assessed whether serum components modulate the effect of platelet preparations. In murine bone marrow cultures, osteoclastogenesis was investigated in the presence of platelet-released supernatant (PRS), serum containing PRS (SC-PRS), and serum. Osteoclastogenesis was quantified by the numbers of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells, TRAP activity and resorption assays. Also human osteoclastogenesis assays were performed. Viability and proliferation were tested by MTT and (3) [H]thymidine incorporation assays, respectively. Osteoblastogenesis was assessed by histochemical staining for alkaline phosphatase-of murine bone marrow cultures and human MG63 cells. We found PRS to increase the number of TRAP(+) multinucleated cells in the early phase and TRAP activity in the later phase of osteoclastogenesis. SC-PRS and serum decreased the number and activity of TRAP(+) multinucleated cells. Both serum containing preparations reduced viability and proliferation of hematopoietic progenitors. PRS decreased the numbers of alkaline phosphatase-positive colonies while SC-PRS and serum increased osteoblastmarkers in MG63. Proliferation of MG63 was stimulated by all preparations. These results show that activated platelets support osteoclastogenesis, while platelet preparations that contain serum components decrease osteoclastogenesis and increase osteoblastogenesis in vitro, suggesting that serum components modulate the effects of platelets on osteoclastogenesis and osteoblastogenesis.

Timing of bacterial carriage sampling in vaccine trials: A modelling study.

BACKGROUND Pathogenic bacteria are often asymptomatically carried in the nasopharynx. Bacterial carriage can be reduced by vaccination and has been used as an alternative endpoint to clinical disease in randomised controlled trials (RCTs). Vaccine efficacy (VE) is usually calculated as 1 minus a measure of effect. Estimates of vaccine efficacy from cross-sectional carriage data collected in RCTs are usually based on prevalence odds ratios (PORs) and prevalence ratios (PRs), but it is unclear when these should be measured. METHODS We developed dynamic compartmental transmission models simulating RCTs of a vaccine against a carried pathogen to investigate how VE can best be estimated from cross-sectional carriage data, at which time carriage should optimally be assessed, and to which factors this timing is most sensitive. In the models, vaccine could change carriage acquisition and clearance rates (leaky vaccine); values for these effects were explicitly defined (facq, 1/fdur). POR and PR were calculated from model outputs. Models differed in infection source: other participants or external sources unaffected by the trial. Simulations using multiple vaccine doses were compared to empirical data. RESULTS The combined VE against acquisition and duration calculated using POR (VEˆacq.dur, (1-POR)×100) best estimates the true VE (VEacq.dur, (1-facq×fdur)×100) for leaky vaccines in most scenarios. The mean duration of carriage was the most important factor determining the time until VEˆacq.dur first approximates VEacq.dur: if the mean duration of carriage is 1-1.5 months, up to 4 months are needed; if the mean duration is 2-3 months, up to 8 months are needed. Minor differences were seen between models with different infection sources. In RCTs with shorter intervals between vaccine doses it takes longer after the last dose until VEˆacq.dur approximates VEacq.dur. CONCLUSION The timing of sample collection should be considered when interpreting vaccine efficacy against bacterial carriage measured in RCTs.