A biomaterial with a channel-like pore architecture induces endochondral healing of bone defects.

Biomaterials developed to treat bone defects have classically focused on bone healing via direct, intramembranous ossification. In contrast, most bones in our body develop from a cartilage template via a second pathway called endochondral ossification. The unsolved clinical challenge to regenerate large bone defects has brought endochondral ossification into discussion as an alternative approach for bone healing. However, a biomaterial strategy for the regeneration of large bone defects via endochondral ossification is missing. Here we report on a biomaterial with a channel-like pore architecture to control cell recruitment and tissue patterning in the early phase of healing. In consequence of extracellular matrix alignment, CD146+ progenitor cell accumulation and restrained vascularization, a highly organized endochondral ossification process is induced in rats. Our findings demonstrate that a pure biomaterial approach has the potential to recapitulate a developmental bone growth process for bone healing. This might motivate future strategies for biomaterial-based tissue regeneration.

Rapid detection of periprosthetic joint infection using a combination of 16s rDNA polymerase chain reaction and lateral flow immunoassay: A Pilot Study.

OBJECTIVES: The objective of this study was to develop a test for the rapid (within 25 minutes) intraoperative detection of bacteria from synovial fluid to diagnose periprosthetic joint infection (PJI). METHODS: The 16s rDNA test combines a polymerase chain reaction (PCR) for amplification of 16s rDNA with a lateral flow immunoassay in one fully automated system. The synovial fluid of 77 patients undergoing joint aspiration or primary or revision total hip or knee surgery was prospectively collected. The cohort was divided into a proof-of-principle cohort (n = 17) and a validation cohort (n = 60). Using the proof-of-principle cohort, an optimal cut-off for the discrimination between PJI and non-PJI samples was determined. PJI was defined as detection of the same bacterial species in a minimum of two microbiological samples, positive histology, and presence of a sinus tract or intra-articular pus. RESULTS: The 16s rDNA test proved to be very robust and was able to provide a result in 97% of all samples within 25 minutes. The 16s rDNA test was able to diagnose PJI with a sensitivity of 87.5% and 82%, and a specificity of 100% and 89%, in the proof-of-principle and validation cohorts, respectively. The microbiological culture of synovial fluid achieved a sensitivity of 80% and a specificity of 93% in the validation cohort. CONCLUSION: The 16s rDNA test offers reliable intraoperative detection of all bacterial species within 25 minutes with a sensitivity and specificity comparable with those of conventional microbiological culture of synovial fluid for the detection of PJI. The 16s rDNA test performance is independent of possible blood contamination, culture time and bacterial species.Cite this article: V. Janz, J. Schoon, C. Morgenstern, B. Preininger, S. Reinke, G. Duda, A. Breitbach, C. F. Perka, S. Geissler. Rapid detection of periprosthetic joint infection using a combination of 16s rDNA polymerase chain reaction and lateral flow immunoassay: A Pilot Study. Bone Joint Res 2018;7:12-19. DOI: 10.1302/2046-3758.71.BJR-2017-0103.R2.

In serum veritas-in serum sanitas? Cell non-autonomous aging compromises differentiation and survival of mesenchymal stromal cells via the oxidative stress pathway.

Even tissues capable of complete regeneration, such as bone, show an age-related reduction in their healing capacity. Here, we hypothesized that this decline is primarily due to cell non-autonomous (extrinsic) aging mediated by the systemic environment. We demonstrate that culture of mesenchymal stromal cells (MSCs) in serum from aged Sprague-Dawley rats negatively affects their survival and differentiation ability. Proteome analysis and further cellular investigations strongly suggest that serum from aged animals not only changes expression of proteins related to mitochondria, unfolded protein binding or involved in stress responses, it also significantly enhances intracellular reactive oxygen species production and leads to the accumulation of oxidatively damaged proteins. Conversely, reduction of oxidative stress levels in vitro markedly improved MSC function. These results were validated in an in vivo model of compromised bone healing, which demonstrated significant increase regeneration in aged animals following oral antioxidant administration. These observations indicate the high impact of extrinsic aging on cellular functions and the process of endogenous (bone) regeneration. Thus, addressing the cell environment by, for example, systemic antioxidant treatment is a promising approach to enhance tissue regeneration and to regain cellular function especially in elderly patients.

In vitro-in vivo evaluation of nanosuspension release from subcutaneously implantable osmotic pumps.

Utilizing poorly soluble drug candidates in pharmacokinetic studies remains challenging in preclinical drug development. We investigated a nanosuspension-based delivery system to achieve constant drug plasma levels by applying the nanoparticles via subcutaneously implanted micro-osmotic pumps. Various nanosuspension formulations were characterized in vitro prior to Alzet® pump release by means of dynamic light scattering (DLS), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and rheological measurements. In vitro formulation release was checked by HPLC/UV. The in vivo experiments compared plasma-concentration time profiles of subcutaneously injected nanosuspensions with those of formulations delivered by pumps. Two Poloxamer 338 containing nanosuspensions with different viscosities were found to be stable over observation time, physically resistant against biorelevant media and showed only a low amorphous part after preparation. The more viscous nanosuspension with 31.65 mPas revealed in vitro the expected zero-order release, while the low viscous formulation with 2.18 mPas showed first order release. In in vivo experiments, the higher viscous nanosuspension released from osmotic pumps exhibited elevated plasma levels compared to the lower viscous formulation. Compared to bolus injected nanosuspensions constant plasma levels could be maintained by adapting the viscosity of the nanosuspension. Subcutaneously implanted osmotic pumps prove to be a valuable delivery system for nanosuspensions in pharmacokinetic studies by consideration of the key parameter viscosity in release kinetics.

How do in-vitro release profiles of nanosuspensions from Alzet® pumps correspond to the in-vivo situation? A case study on radiolabeled fenofibrate.

In research and development sufficiently high and constant plasma levels of drug candidates are often requested, but simple solutions of hydrophobic drugs delivered from the commonly used micro-osmotic pumps cannot meet these demands. Nanosuspensions released from implanted osmotic devices can be a strategy to overcome this challenge but little is known about their pharmacokinetic behavior after subcutaneous application. In the current study, four different nanosuspension formulations containing iodinated fenofibrate were prepared, physicochemically characterized and investigated concerning their in-vitro release kinetics from osmotic pumps. One nanosuspension of lower viscosity exhibited thereby an unexpectedly first order release kinetics, whereas the higher viscous counterpart was released in the expected zero-order manner. To assess the relation of the in-vitro release kinetics to the in-vivo fate of nanosuspensions, various [(131)I] iodinated fenofibrate formulations were subcutaneously applied to mice. The biodistribution was followed by means of γ-scintigraphy and γ-scintillation. Two different nanosuspensions released from osmotic pumps were compared to bolus injections of a nanosuspension and an organic drug solution. The distribution and elimination of the bolus injected drug solution were almost completed within 48h. In contrast, a long lasting (>1week) depot at the injection site was formed by the bolus injected nanosuspension. Ex vivo examination of the organs showed a sustained, but exponential decrease of the radiolabel concentration. More constant drug levels in the organs were achieved within the nanosuspensions released from osmotic pumps. The organ levels of [(131)I] labeled fenofibrate were found to be more constant in case of the pump with the higher viscous nanosuspension in contrast to the lower viscous counterpart. However, the very different release profiles of the lower and higher viscous nanosuspension observed in-vitro were not observed in-vivo, as both pumps showed zero order release. In conclusion, nanosuspensions of poorly soluble compounds released from subcutaneously implanted osmotic pumps can be a suitable approach in pharmacokinetic studies. Although the in-vivo release of nanosuspensions differed in the expected release profile from the in-vitro test results, these in-vitro release tests present a valuable tool for the pre-selection of suitable nanosuspension candidates.

CD73/5'-ecto-nucleotidase acts as a regulatory factor in osteo-/chondrogenic differentiation of mechanically stimulated mesenchymal stromal cells.

Bone regeneration is influenced by mesenchymal stromal cells (MSCs) and mechanical conditions. How healing outcome and mechanical stability are linked on the cellular level, however, remains elusive. Cyclic-compressive loading of MSCs affects the expression of molecules involved in angiogenesis and matrix assembly, but also reduces the expression of CD73, an ecto-5'-nucleotidase, which plays a crucial role in extracellular adenosine generation. Although, for almost 20 years, CD73 has been a major cell surface marker defining MSCs, little is known about its function in these cells. Therefore, the aim of this study was to determine the putative involvement of CD73 in MSC differentiation after cyclic-compressive loading. After cultivation in appropriate differentiation media, chondrogenic differentiation ability was significantly increased in loaded MSCs, hence following current models. Through treatment with the CD73 inhibitor adenosine 5'-(α, ß-methylene) diphosphate, chondrogenic matrix deposition was further increased; in contrast, mineral matrix deposition and expression of osteogenic markers was reduced. One major signal transduction pathway, which is activated via CD73-mediated adenosine, is the adenosine receptor pathway. Thus, the adenosine receptor expression pattern was investigated. MSCs expressed the four known adenosine receptors at the mRNA level. After mechanical stimulation of MSCs, Adora2a was down-regulated. These data point towards a role of CD73 in MSC differentiation possibly via A2AR signalling, which is mutually regulated with CD73. In conclusion, the findings of this study suggest that CD73 is another regulatory factor in osteo-/chondrogenic differentiation of MSCs and may provide a - thus far underestimated - therapeutic target to guide bone regeneration.

Weak localization in ferromagnetic (Ga,Mn)as nanostructures.

We report on the observation of weak localization in arrays of (Ga,Mn)As nanowires at millikelvin temperatures. The corresponding phase coherence length L phi is typically between 100 and 200 nm at 20 mK. Strong spin-orbit interaction in the material is manifested by a weak antilocalization correction around zero magnetic field.

[Prospective multi-center study colon/rectum carcinoma (primary tumors)--Results of the year 2000]. / Prospektive Multizenterstudie "Kolon-/Rektum Karzinome (Primärtumor)" - Uberblick über den Jahrgang 2000.

INTRODUCTION: Surgical quality control in the form of multicentre studies make it possible to analyse the treatment status of a given surgical illness under quality assurance aspects. MATERIAL/METHODS: On 1. 1. 2000, under the patronage of the Convent of Hospital Chief Surgeons a project (ongoing) - organised and conducted by the Institute for Quality Management in Operative Medicine at the Otto-von-Guericke University of Magdeburg - was initiated to document and collect the data of patients with colorectal cancer throughout the whole of Germany. This work is supported by the German Society of Surgery, and the Surgical Working Group, Quality Assurance within the German Society of Surgery. Currently, some 282 hospitals throughout the country are involved in establishing a prospective documentation of colorectal carcinoma. Participation in this study is on a voluntary basis. The anonymity of both patients and hospitals is guaranteed, and no hospitals wishing to participate are excluded. Both operatively and conservatively treated patients are being documented, and no randomization takes place. RESULTS: In the year 2000, the participating hospitals documented a total of 9 477 patients with a colorectal carcinoma, including 6 975 patients with a carcinoma of the colon, and 3 402 with a rectal carcinoma. The average age of the patients was 68.5 years, and there were 5 010 men and 4 467 women. The operation rate was 99.2 %, the resection rate 95.6 %. The abdominoperineal resection rate was 27.4 %. The indicators for diagnostic quality as set out by Hermanek were largely complied with, but some deviations were noted. DISCUSSION: On the basis of the data collected, structures were established for a uniform Germany-wide quality management for a clinical condition with a major health policy impact. This information make it possible for the hospitals to identify and eliminate deficits in the structural and process quality in the diagnosis and treatment of colorectal cancer, and in this way to improve outcome quality. This means that the results of medical care research have an immediate impact on the individual treatment received by a given patient.

["Colon-/rectal carcinoma" prospective studies as comprehensive surgical quality assurance]. / Prospektive Multizenterstudien "Kolon-/Rektumkarzinome" als flächendeckende chirurgische Qualitätssicherung.

INTRODUCTION: Currently, only a small percentage of the diagnostic and therapeutic data on colonic carcinomas has been confirmed by data obtained in randomized controlled studies. For this reason, the results of prospective multicentre observational studies are extremely important. METHOD: Within a multicentre observational study involving 75 surgical departments carried out between 01.01. and 31.12.1999, 3,756 patients with a colorectal carcinoma (2,293 carcinoma of the colon; 1,463 carcinomas or the rectum) were investigated prospectively using a standardised questionnaire. RESULTS: The OP rate was 98.4%, the resection rate 92.5% (colon 94.1%, rectum 89.9%). The rate of rectal extirpations was relatively high at 30.3%. General postoperative morbidity was 27.4% (colon 27.0%, rectum 27.9%); the specific postoperative morbidity was 24.6% (colon 21.8%, rectum 29.1%). The anastomotic insufficiency rate was 5.2% (colon 3.7%, rectum 9.5%). The 30-day mortality rate was 4.7%, and the postoperative mortality rate 5.7%. CONCLUSIONS: Surgical quality control in the form of prospective multicentre observational studies make possible the analysis of the therapeutic situation of a surgical disease under quality assurance aspects. At the same time, the comprehensive data material available will serve the specific planning of prospective randomized studies. With the aid of the present study, a basis for a thorough and complete evaluation of colorectal carcinoma has been created.

Process balance and product quality in the production of natural indigo from Polygonum tinctorium Ait. applying low-technology methods.

Indigo is the most important blue component in the class of natural dyes for cellulose and protein fibres. In the moderate European climate Polygonum tinctorium Ait. could be an interesting source for natural indigo (Vat blue 1). Following a cultivation of the plant material a simple procedure for the extraction of the indigo precursor indican was investigated with regard to crop and quality of dye obtained. The dependence of the crop on the storage conditions of the harvested plant material was investigated. The results quantify the distinct sensitivity of the fresh material to the time of storage before extraction with regard to the amount of natural indigo obtained, the photometrically determined indigo content in the product and the shade and colour depth observed in standardised dyeing experiments. A basic set of data is presented, which describes the process in terms of consumption of energy, water and chemicals and organic waste released from the extraction step.

Effect of caseload on the short-term outcome of colon surgery: results of a multicenter study.

This prospective multicenter study investigated the effect of hospital caseload on early postoperative outcome of surgery for carcinoma of the colon in 75 German hospitals and included 2293 patients. The hospitals were divided into those with a caseload of 1-30 (group A), 31-60 (group B), and more than 60 (group C) operations. Increasing caseload was associated only with fewer general postoperative complications. It was also associated with significantly greater use of antibiotic prophylaxis. No significant differences between the groups were found in resection rates, intraoperative complications, specific postoperative complications, overall postoperative morbidity, hospital mortality, or 30-day mortality. The significance of hospital caseload for the short-term postoperative outcome following surgery on the colon should not be overestimated. Basing conclusions about the results to be expected simply on the case volume is impermissible. On the basis of the available data it is not possible to establish a threshold value, that is, a minimum number of required operations.

Anorexia in rats infected with the nematode, Nippostrongylus brasiliensis: experimental manipulations.

Nippostrongylus brasiliensis induces a biphasic anorexia in laboratory rats, the first phase coincident with lung invasion (ca day 2) and the second when the worms mature in the intestine (ca day 8). Using the anthelminthic, mebendazole (MBZ), N. brasiliensis infections of the rat were eliminated between the first and second anorexic episodes. This intervention prevented the expression of the second phase of anorexia. Rats exposed to a second infection with N. brasiliensis, 3 weeks after the primary infection, exhibited only a first phase anorexic response which was not influenced by MBZ termination of the primary infection. The lower cumulative food intake and weight gain of all infected rats after 8 days of infection were accompanied by elevated plasma insulin and, in some individuals, by elevated plasma leptin, compared with uninfected controls and previously-infected MBZ-treated rats. Messenger RNA levels for neuropeptide Y were higher in the hypothalamic arcuate nucleus of 8-day infected rats than in recovering MBZ-treated animals. Inoculation of rats with heat-killed N. brasiliensis larvae failed to induce anorexia and did not alter the severity of biphasic anorexia on subsequent injection of viable larvae. The first anorexic episode is therefore dependent upon viable migrating larvae. The second phase of anorexia clearly requires the continuing presence of the parasite beyond the lung phase. Viable migrating larvae are also required to confer 'resistance' to reinfection.

Toxoplasma gondii infection: analysis of serological response by 2-DE immunoblotting.

Toxoplasma gondii is known to cause a variety of diseases ranging from asymptomatic infections to serious conditions in immunocompromised hosts such as AIDS-patients or transplant recipients. In addition they may cause abortion or fetal abnormalities during pregnancy. Despite the clinical importance, diagnosis, treatment and prevention still remain unsatisfactory. Analysis of the parasitic cell determinants, recognized by specific humoral and cellular immune responses, may have important implications for diagnosis, therapy and vaccination strategies. Two-dimensional electrophoresis (2-DE) was used to resolve and compare protein patterns from Toxoplasma gondii strains RH and BK (mouse virulent strains). Comparison of silver-stained gels showed that 35.2% to 60.3% of the spots had the same position. In a second series of experiments, the reactivity of the spots with human sera was tested. Proteins were transferred to PVDF membranes and were detected with sera from different patient groups. Depending upon the immunoglobulin class (IgG, IgM, IgA or IgE) different epitope patterns were observed. Some of the spots seemed to be recognized in different stages of infection. Sera of two patients with similar serology and comparable stage of infection were compared in order to demonstrate an individual immune response.

A novel protein complex promoting formation of functional alpha- and gamma-tubulin.

We describe the identification of GIM1/YKE2, GIM2/PAC10, GIM3, GIM4 and GIM5 in a screen for mutants that are synthetically lethal with tub4-1, encoding a mutated yeast gamma-tubulin. The cytoplasmic Gim proteins encoded by these GIM genes are present in common complexes as judged by co-immunoprecipitation and gel filtration experiments. The disruption of any of these genes results in similar phenotypes: the gim null mutants are synthetically lethal with tub4-1 and super-sensitive towards the microtubule-depolymerizing drug benomyl. All except Deltagim4 are cold-sensitive and their microtubules disassemble at 14 degrees C. The Gim proteins have one function related to alpha-tubulin and another to Tub4p, supported by the finding that the benomyl super-sensitivity is caused by a reduced level of alpha-tubulin while the synthetic lethality with tub4-1 is not. In addition, GIM1/YKE2 genetically interacts with two distinct classes of genes, one of which is involved in tubulin folding and the other in microtubule nucleation. We show that the Gim proteins are important for Tub4p function and bind to overproduced Tub4p. The mammalian homologues of GIM1/YKE2 and GIM2/PAC10 rescue the synthetically lethal phenotype with tub4-1 as well as the cold-sensitivity and benomyl super-sensitivity of the yeast deletion mutants. We suggest that the Gim proteins form a protein complex that promotes formation of functional alpha- and gamma-tubulin.

The spindle pole body component Spc97p interacts with the gamma-tubulin of Saccharomyces cerevisiae and functions in microtubule organization and spindle pole body duplication.

Previously, we have shown that the gamma-tubulin Tub4p and the spindle pole body component Spc98p are involved in microtubule organization by the yeast microtubule organizing centre, the spindle pole body (SPB). In this paper we report the identification of SPC97 encoding an essential SPB component that is in association with the SPB substructures that organize the cytoplasmic and nuclear microtubules. Evidence is provided for a physical and functional interaction between Tub4p, Spc98p and Spc97p: first, temperature-sensitive spc97(ts) mutants are suppressed by high gene dosage of SPC98 or TUB4. Second, Spc97p interacts with Spc98p and Tub4p in the two-hybrid system. Finally, immunoprecipitation and fractionation studies revealed complexes containing Tub4p, Spc98p and Spc97p. Further support for a direct interaction of Tub4p, Spc98p and Spc97p comes from the toxicity of strong SPC97 overexpression which is suppressed by co-overexpression of TUB4 or SPC98. Analysis of temperature-sensitive spc97(ts) alleles revealed multiple spindle defects. While spc97-14 cells are either impaired in SPB separation or mitotic spindle formation, spc97-20 cells show an additional defect in SPB duplication. We discuss a model in which the Tub4p-Spc98p-Spc97p complex is part of the microtubule attachment site at the SPB.

The spindle pole body component Spc98p interacts with the gamma-tubulin-like Tub4p of Saccharomyces cerevisiae at the sites of microtubule attachment.

Tub4p is a novel tubulin found in Saccharomyces cerevisiae. It most resembles gamma-tubulin and, like it, is localized to the yeast microtubule organizing centre, the spindle pole body (SPB). In this paper we report the identification of SPC98 as a dosage-dependent suppressor of the conditional lethal tub4-1 allele. SPC98 encodes an SPB component of 98 kDa which is identical to the previously described 90 kDa SPB protein. Strong overexpression of SPC98 is toxic, causing cells to arrest with a large bud, defective microtubule structures, undivided nucleus and replicated DNA. The toxicity of SPC98 overexpression was relieved by co-overexpression of TUB4. Further evidence for an interaction between Tub4p and Spc98p came from the synthetic toxicity of tub4-1 and spc98-1 alleles, the dosage-dependent suppression of spc98-4 by TUB4, the binding of Tub4p to Spc98p in the two-hybrid system and the co-immunoprecipitation of Tub4p and Spc98p. In addition, Spc98-1p is defective in its interaction with Tub4p in the two-hybrid system. We suggest a model in which Tub4p and Spc98p form a complex involved in microtubule organization by the SPB.