[What role does soft tissue play in callus distraction? An animal experiment]

BACKGROUND

Extremity conserving treatment in hospitals of maximum care involves a combination of soft tissue replacement and segment transfer. In contrast some other countries favour the segment transfer without soft tissue replacement and can demonstrate good results. Thus, we posed the question of the effects of soft tissue defects in callus distraction.

MATERIALS AND METHODS

In an experimental study with two groups of sheep, a standardized fracture model in one group with bone and soft tissue defects and in the other group without soft tissue defects was compared. At specific dates the animals were euthanized and the bone quality combined with different soft tissue conditions were quantified.

RESULTS

At the outset of callus maturation, animals without soft tissue defects have a lead over animals with soft tissue defects. At the end of the experimental study both groups show the same bone quality results compared to a healthy comparison group.

CONCLUSION

At the terminal phase of the animal experiment the results of open segment transfer show no differences between the groups with or without soft tissue defects. This supports the experience of other countries. Because of the experimental set-up we cannot make any prediction regarding the biomechanical stability of the callus.

[Biochemical control of callus maturation--an experimental animal study]

AIM OF THE STUDY

The purpose of this study was to verify the possibility of monitoring the callus maturation biochemically.

METHOD

In an experimental study on sheep, animals with bone fractures with a length 5 cm each were divided into group A (with concomitant damage of the soft tissue) and group B (without soft tissue damage). During callus traction and maturation, biochemical parameters (osteocalcin, AlP, NTx, calcium, phosphate) were measured. Animals of each group (A+B) were euthanised at fixed points in time (according to protocol) and the callus was prepared histologically.

RESULTS

Total AlP and NTx values were initially reduced during the callus traction and maturation, but increased significantly at the time of Docking+1 transportation time. At the same time, the histological evaluation showed a definite increase of the bone stabilisation, which approximately resembles the structure of a healthy bone as reference.

CONCLUSION

With the combination of the AlP and NTx values already determined in the daily clinical routine the monitoring of callus maturation in animal studies becomes possible.

[A new possibility for determining the size and position of the tricortical bone graft in ventral spine stabilisation]

AIM

Ventral stabilisation of thoracolumbar fractures is often done with autogenous iliac crest grafts as an alternative to other filling and stabilisation systems. Today the golden standard for this kind of reconstruction is the minimally invasive thoracoscopic stabilization. Often there was a problem with the determination of the size and the position of the graft, especially on video-assisted minimally invasive stabilisation. The aim of this study was now to develop a new instrument that would be able to minimise this kind of intraoperative problems.

METHOD

For measuring and for checking the exact position of the bone graft the vertebrometer as a new measuring apparatus was developed. With the simple and good handling of the vertebrometer, there is an easy possibility of determine the size and the position of the graft. As this tool is made of metal, it is possible to localise and to check the positioning and the right size of the necessary bone graft during the intraoperative radiological control.

DISCUSSION

This tool may help to improve the prognosis of osseous integration of the implanted material and lower the rate of pseudarthrosis. Furthermore, the handling of the thoracoscopic ventral stabilisation may be somewhat easier and, even for the inexperienced surgeon, there is now an instrument available to fit in the graft with a satisfactory result.

The immune system in healthy adults and patients with atopic dermatitis seems to be affected differently by a probiotic intervention

BACKGROUND

Probiotic bacteria are proposed to alleviate atopic dermatitis (AD) in infants. There are few indications about the effect of probiotics on AD in adults.

OBJECTIVE

The purpose of this study was to elucidate the influence of a probiotic drink containing a combination of the probiotics Lactobacillus paracasei Lpc-37, Lactobacillus acidophilus 74-2 and Bifidobacterium animalis subsp. lactis DGCC 420 (B. lactis 420) in healthy volunteers and in patients with AD on clinical and immunological parameters and their detection in feces.

METHODS

A double-blind, placebo-controlled, randomized cross-over study was conducted in 15 healthy adults and 15 patients with AD. The probiotic product or placebo was given over 8 weeks. A 2-week washout period was interconnected before the intervention was crossed. At the end of each period, blood and stool samples were collected. In patients, the severity of AD was evaluated using the Scoring of Atopic Dermatitis (SCORAD).

RESULTS

L. paracasei and B. lactis were recovered in high numbers in feces after supplementation, whereas L. acidophilus marginally increased. In patients, the SCORAD tended to decrease by 15.5% (P=0.081). Major lymphocyte subsets were not affected by the probiotic intervention. However, CD57(+) increased significantly (P=0.034) in healthy subjects after probiotic intake and was not changed in patients, whereas CD4(+)CD54(+) decreased significantly (P=0.031) in patients with AD and remained uninfluenced in healthy subjects. The expression of CD4(+)CD25(+) T cells was similar in healthy subjects and AD patients. The phagocytic activity of monocytes and granulocytes was significantly increased in healthy subjects after probiotic intervention (P=0.014).

CONCLUSION

L. paracasei Lpc-37 and B. lactis 420 are able to colonize the intestine transiently. This study reveals that the probiotics differently modulate peripheral immune parameters in healthy subjects and patients with AD.

De novo Crohn's disease in a renal transplant recipient

The prevalence of inflammatory bowel disease (IBD) after renal transplantation is affected by the immune tolerance and the modality of immunosuppression. Mycophenolate mofetil (MMF) may have a promoting effect on the development of posttransplantation erosive enterocolitis and a Crohn's disease-like pattern of colitis. We have presented a 40-year-old man with end-stage renal disease due to chronic glomerulonephritis who commenced hemodialysis for 2 months before receipt of a live unrelated renal transplant. He developed early posttransplantation diabetes mellitus and an anti graft rejection episode, which responded to a methylprednisolone pulse and OKT3 treatment. His immunosuppressive regimen included prednisolone, MMF, and tacrolimus. Three years after transplantation, he developed mild constitutional symptoms, mouth ulcerations, and chronic intermittent bloody diarrhea. Colonoscopy showed active segmental colitis with aphthous ulcers, involving the proximal descending colon and the splenic flexure. Colonic biopsies showed distended and branched crypts in the ascending colon, moderate active chronic colitis with regenerative atypia, skipping appearance, and ulceration in the splenic flexure and descending colon. The edematous crypts were associated with ulcerations in the sigmoid colon and rectum. The features were highly suggestive of Crohn's disease. He was successfully treated with high-dose steroids and 5-aminosalicylic acid. Subsequently, he developed chronic transplant glomerulopathy and restarted hemodialysis. We concluded that de novo Crohn's disease may develop in renal transplant recipients despite immunosuppressive therapy especially with MMF immunosuppression.

Role of nitrogen oxides in the metabolism of ammonia-oxidizing bacteria

Ammonia-oxidizing bacteria (AOB) can use oxygen and nitrite as electron acceptors. Nitrite reduction by Nitrosomonas is observed under three conditions: (i) hydrogen-dependent denitrification, (ii) anoxic ammonia oxidation with nitrogen dioxide (NO(2)) and (iii) NO(x)-induced aerobic ammonia oxidation. NO(x) molecules play an important role in the conversion of ammonia and nitrite by AOB. Absence of nitric oxide (NO), which is generally detectable during ammonia oxidation, severely impairs ammonia oxidation by AOB. The lag phase of recovery of aerobic ammonia oxidation was significantly reduced by NO(2) addition. Acetylene inhibition tests showed that NO(2)-dependent and oxygen-dependent ammonia oxidation can be distinguished. Addition of NO(x) increased specific activity of ammonia oxidation, growth rate and denitrification capacity. Together, these findings resulted in a hypothetical model on the role of NO(x) in ammonia oxidation: the NO(x) cycle.

1994-2004: 10 years of research on the anaerobic oxidation of ammonium

The obligately anaerobic ammonium oxidation (anammox) reaction with nitrite as primary electron acceptor is catalysed by the planctomycete-like bacteria Brocadia anammoxidans, Kuenenia stuttgartiensis and Scalindua sorokinii. The anammox bacteria use a complex reaction mechanism involving hydrazine as an intermediate. They have a unique prokaryotic organelle, the anammoxosome, surrounded by ladderane lipids, which exclusively contains the hydrazine oxidoreductase as the major protein to combine nitrite and ammonia in a one-to-one fashion. In addition to the peculiar microbiology, anammox was shown to be very important in the oceanic nitrogen cycle, and proved to be a very good alternative for treatment of high-strength nitrogenous waste streams. With the assembly of the K. stuttgartiensis genome at Genoscope, Evry, France, the anammox reaction has entered the genomic and proteomic era, enabling the elucidation of many intriguing aspects of this fascinating microbial process.

Anaerobic ammonium oxidation by marine and freshwater planctomycete-like bacteria

Recently, two fresh water species, " Candidatus Brocadia anammoxidans" and " Candidatus Kuenenia stuttgartiensis", and one marine species, " Candidatus Scalindua sorokinii", of planctomycete anammox bacteria have been identified. " Candidatus Scalindua sorokinii" was discovered in the Black Sea, and contributed substantially to the loss of fixed nitrogen. All three species contain a unique organelle--the anammoxosome--in their cytoplasm. The anammoxosome contains the hydrazine/hydroxylamine oxidoreductase enzyme, and is thus the site of anammox catabolism. The anammoxosome is surrounded by a very dense membrane composed almost exclusively of linearly concatenated cyclobutane-containing lipids. These so-called 'ladderanes' are connected to the glycerol moiety via both ester and ether bonds. In natural and man-made ecosystems, anammox bacteria can cooperate with aerobic ammonium-oxidising bacteria, which protect them from harmful oxygen, and provide the necessary nitrite. The cooperation of these two groups of ammonium-oxidising bacteria is the microbial basis for a sustainable one reactor system, CANON (completely autotrophic nitrogen-removal over nitrite) to remove ammonia from high strength wastewater.

Parvovirus B19 DNA in plasma pools and plasma derivatives

BACKGROUND AND OBJECTIVES

Human parvovirus B19 (B19) has been transmitted by various plasma-derived medicinal products. The aim of this study was to determine the frequency and the level of B19 DNA contamination in plasma pools destined for fractionation and in a broad range of plasma derivatives. In addition, removal of B19 DNA by the manufacturing process was investigated in cases where corresponding samples from plasma pool and product were available.

MATERIALS AND METHODS

Plasma pool samples and blood products were tested for B19 DNA by nested polymerase chain reaction (PCR), and the viral DNA content was determined by TaqMan quantitative PCR.

RESULTS

Two-hundred and twenty two of 372 plasma pools for fractionation contained B19 DNA at concentrations of 10(2)-10(8) genome equivalents/ml (geq/ml). While approximately 65% of the DNA-positive plasma pools were only moderately contaminated (< 10(5) geq/ml), 35% contained > 10(6) geq/ml. High frequencies of contamination were detected in Factor VIII (79 of 91), prothrombin complex concentrates (38 of 43) and Factor IX (41 of 62), where the concentration of B19 DNA ranged between 102 and 107 geq/ml. A lower level of B19 DNA contamination was found in antithrombin III (five of 26 samples), in anti-D immunoglobulins (three of 37 samples) and in albumin (four of 51 samples), with levels ranging between 10(2) and 10(3) geq/ml. Furthermore, investigation of plasma pools for solvent/detergent plasma (S/D plasma), from two manufacturers, revealed B19 DNA in 15 of 66 batches at concentrations of 10(2)-10(8) geq/ml. Similar concentrations were detected in the corresponding final S/D plasma products. Anti-B19 immunoglobulin G (IgG) was found in plasma pools and S/D plasma at concentrations of approximately 40 IU/ml.

CONCLUSION

Although positive PCR results do not necessarily reflect infectivity, these data show that B19 is a common contaminant in plasma pools and in plasma-derived medicinal products. Considering the resistance of animal parvoviruses to inactivation by heat and chemical agents, and the absence of specific information for B19, the risk of B19 transmission by plasma products should be considered. Physicians should be aware of this problem when treating patients of B19-related risk groups. The plasma fractionation industry should continue their efforts to avoid B19 contamination of plasma derivatives and develop methods which are effective in removing/inactivating parvovirus B19.

Gaseous NO2 as a regulator for ammonia oxidation of Nitrosomonas eutropha

Cells of Nitrosomonas eutropha strain N904 that were denitrifying under anoxic conditions with hydrogen as electron donor and nitrite as electron acceptor were unable to utilize ammonium (ammonia) as an energy source. The recovery of ammonia oxidation activity was dependent on the presence of NO2. Anaerobic ammonia oxidation activity was observed in a helium atmosphere supplemented with 25 ppm NO2 after 20 h. Ammonia oxidation activity was detected after 2-3 days using an oxic atmosphere with 25 ppm NO2. In contrast, ammonia consumption started after 8-9 days under oxic conditions without the addition of NO2; in this case, small amounts of NO and NO2 were detected and their concentrations increased with increasing ammonia oxidation activities. Hardly any ammonia oxidation was detected when nitrogen oxides were removed by intensive aeration. It would seem, therefore, that NO2 is the master regulatory signal for ammonia oxidation in Nitrosomonas eutropha. Anaerobic ammonia oxidation activity was inhibited by the addition of NO. This inhibition was partly compensated by either increasing the NO2 concentration or by using 2,3-dimercapto-1-propane-sulfonic acid as a NO binding substrate. DMPS was inhibitory to nitrification under oxic conditions, while increased amounts of NO or NO2 led to increased oxidation activities.

The effect of leptin treatment on the development of obesity in overfed suckling Wistar rats

OBJECTIVE

To identify the role of hyperleptinaemia in mediating the effects of early postnatal overfeeding in a rat strain known to be prone to manipulations of the early environment which result in predispositions for obesity and associated metabolic and cardiovascular disturbance in later life.

DESIGN

Wistar rats were reared in normal litters (NL, 10--12 pups) or small litters (SL, four pups) from postnatal day 3 and killed for determination of body composition and plasma leptin and insulin concentrations on day 7 or day 21 after having been treated with recombinant leptin (2 x 50 (pmol/g)/day) or saline from day 1.

RESULTS

Rearing in SL doubled the body fat content and plasma leptin levels in comparison to NL pups by 21 days of age. Under leptin-treatment throughout suckling age, NL pups remained leptin responsive, ie the difference in body fat content was progressively reduced relative to the controls. Until 7 days of age, despite the body fat content of untreated SL pups being 2-fold higher and their plasma leptin level 7-fold higher than that of NL pups, leptin treatment caused the same percentage decreases in body fat in SL than in NL pups. But in contrast to NL pups, the SL pups became leptin resistant thereafter. Plasma insulin levels in 7-day-old leptin-treated SL pups were 3-fold higher than in untreated littermates and 5-fold higher than in the NL groups.

CONCLUSION

Prophylactic leptin treatment does not prevent hyperinsulinaemia and excessive fat deposition in SL pups. On the other hand, selective hyperleptinaemia during suckling age does not trigger leptin resistance and obesity in NL pups. Rather than hyperleptinaemia per se, other factors associated with early postnatal overnutrition, for example, the concurrent hyperinsulinaemia, seem to play a pivotal role for the development of leptin-resistance and life-long obesity risk in SL rats.

The association of the involvement of financial compensation with the outcome of cervicobrachial pain that is treated conservatively

OBJECTIVES

To examine the influence of the involvement of financial compensation on the results of physiotherapeutic McKenzie treatment on cervicobrachial pain.

METHODS

A prospective study was carried out with a cohort of 60 patients referred to two spine clinics after they had experienced at least 5 weeks of neck pain radiating to the arm. Follow-up was performed 1 yr later using a validated questionnaire to measure the outcomes of neck and arm pain, disability, the use of analgesics and the perceived effect of the treatment as reported by the patient.

RESULTS

At follow-up, there was no improvement in the group of patients for whom financial compensation was involved, whereas the group for whom compensation was involved showed highly significant improvement.

CONCLUSIONS

Despite uniform selection criteria and similarity of complaints and treatment protocols, the involvement of financial compensation seemed to be associated with an adverse effect on treatment results for patients with cervicobrachial pain who were treated conservatively.