CT-Guided Biopsy in Suspected Spondylodiscitis – The Association of Paravertebral Inflammation with Microbial Pathogen Detection

Objectives

To search for imaging characteristics distinguishing patients with successful from those with futile microbiological pathogen detection by CT-guided biopsy in suspected spondylodiscitis.

Methods

34 consecutive patients with suspected spondylodiscitis underwent CT-guided biopsy for pathogen detection. MR-images were assessed for inflammatory infiltration of disks, adjacent vertebrae, epidural and paravertebral space. CT-images were reviewed for arrosion of adjacent end plates and reduced disk height. Biopsy samples were sent for microbiological examination in 34/34 patients, and for additional histological analysis in 28/34 patients.

Results

Paravertebral infiltration was present in all 10/10 patients with positive microbiology and occurred in only 12/24 patients with negative microbiology, resulting in a sensitivity of 100% and a specificity of 50% for pathogen detection. Despite its limited sensitivities, epidural infiltration and paravertebral abscesses showed considerably higher specificities of 83.3% and 90.9%, respectively. Paravertebral infiltration was more extensive in patients with positive as compared to negative microbiology (p = 0.002). Even though sensitivities for pathogen detection were also high in case of vertebral and disk infiltration, or end plate arrosion, specificities remained below 10%.

Conclusions

Inflammatory infiltration of the paravertebral space indicated successful pathogen detection by CT-guided biopsy. Specificity was increased by the additional occurrence of epidural infiltration or paravertebral abscesses.     

Unraveling the naturalness of sweet chestnut forests (<Emphasis Type="Italic">Castanea sativa</Emphasis> Mill.) in central Spain

This paper describes the patterns and processes of vegetation change and fire history in the Late Holocene (c. 3,140 cal bp) palaeoecological sequence of El Tiemblo, in a mountainous area in central Spain (Gredos range, Spanish Central System), and provides the first Iberian pollen sequence undertaken within a Castanea sativa-dominated woodland. These new data reassess not only the autochthonous nature of the species in the region and in the Iberian Peninsula, but also the naturalness of well-developed sweet chestnut forests. The study focuses on anthropogenic dynamics linked both to the effects of livestock husbandry and the use of fire for forest clearance. With this aim, non-pollen palynomorphs (coprophilous fungi ascospores) and charcoal accumulation rate are useful indicators for assessing the increasing role of human influence on vegetation.     

Freezing-altered palatability of Bradford pear to Japanese beetle: evidence for decompartmentalization and enzymatic degradation of feeding deterrents

The basis for resistance of Bradford callery pear, Pyrus calleryana Decaisne Bradford, [Rosaceae] to the Japanese beetle, Popillia japonica Newman, was investigated. Chloroform-dipping rendered leaves palatable, initially suggesting that deterrent waxes had been removed. However, extracts containing surface waxes were not deterrent. Subsequent experiments showed that increased palatability of solvent-dipped leaves is associated with enzymatic tissue browning, characteristic of polyphenol oxidases, rather than simply release of phagostimulants from surface disruption of damaged leaves. Frozen and thawed leaves showed similar browning, becoming increasingly palatable for several hours after thawing. Palatability changes were temperature- and aerobic-sensitive, further evidence that oxidizing enzymes are involved. Juice from leaves that had been frozen and thawed stimulated feeding on glass fiber disks, whereas fresh leaf juice did not. Survival and fecundity were much higher for beetles fed frozen and thawed or chloroform-dipped Bradford pear leaves than for beetles fed normal leaves. We hypothesize that decompartmentalization of deterrent compounds, possibly phenolics, followed by enzymatic oxidation and altered leaf chemistry may explain the increased palatability of chloroform-dipped or frozen and thawed Bradford pear tissue to P. japonica. This approach may be helpful in identifying specific compounds responsible for resistance of woody plants to generalist insects.     

Extracellular and intracellular acid-base status with regard to the energy metabolism in the oyster Crassostrea gigas during exposure to air

The acid-base status of extra- and intracellular fluids was studied in relation to the anaerobic energy metabolism in the adductor muscle, mantle, gills, and heart of the marine bivalve Crassostrea gigas after exposure to air for periods of 2, 4, 8, 12, 24, and 48 h. Such exposure was found to cause a significant reduction in the pH in the hemolymph (pH(e)) within the first 4 h. The decrease in the pHe was accompanied by elevated Pco2 values, causing [HCO3-] to rise (respiratory acidosis). Thereafter, the pHe fell at a lower rate, and this fall was partially compensated for by a further increase in [HCO3-] in the hemolymph. The increase in the [Ca] levels in the hemolymph indicates a mobilization of Ca2+ from CaCO3 and the involvement of bicarbonates in the buffering of pHe. The main anaerobic end-products that accumulated in the tissues during the first stages of anaerobiosis were alanine and succinate, at a ratio of about 2 : 1. Later on, propionate and acetate were also accumulated at significant rates. In contrast to the adductor muscle, gills, and mantle, opine production in the heart was significant after 12-24 h of exposure to air. Determination of intracellular pH (pHi) revealed that there is a close relationship between the rate of anaerobic end-product accumulation and the extent of intracellular acidosis in the adductor muscle, mantle, and gills. On the contrary, accumulation of anaerobic end-products in the heart did not cause any significant change in its pHi. The intracellular nonbicarbonate, nonphosphate buffering value (beta (NB,NPi)) was determined to be higher in the heart than in the other three tissues and thus probably plays a crucial role in stabilizing heart pHi during exposure to air.     

Decreased neoblast progeny and increased cell death during starvation-induced planarian degrowth

The development of a complex multicellular organism requires a careful coordination of growth, cell division, cell differentiation and cell death. All these processes must be under intricate and coordinated control, as they have to be integrated across all tissues. Freshwater planarians are especially plastic, in that they constantly replace somatic tissues from a pool of adult somatic stem cells and continuously undergo growth and degrowth as adult animals in response to nutrient availability. During these processes they appear to maintain perfect scale of tissues and organs. These life history traits make them an ideal model system to study growth and degrowth. We have studied the unique planarian process of degrowth. When food is not available, planarians are able to degrow to a minimum size, without any signs of adverse physiological outcomes. For example they maintain full regenerative capacity. Our current knowledge of how this is regulated at the molecular and cellular level is very limited. Planarian degrowth has been reported to result from a decrease in cell number rather than a decrease in cell size. Thus one obvious explanation for degrowth would be a decrease in stem cell proliferation. However evidence in the literature suggests this is not the case. We show that planarians maintain normal basal mitotic rates during degrowth but that the number of stem cell progeny decreases during starvation and degrowth. These observations are reversed upon feeding, indicating that they are dependent on nutritional status. An increase in cell death is also observed during degrowth, which is not rapidly reversed upon feeding. We conclude that degrowth is a result of cell death decreasing cell numbers and that the dynamics of neoblast self-renewal and differentiation adapt to nutrient conditions to allow maintenance of the neoblast population during the period of starvation.     

In vivo site-specific recombination using the beta-rec/six system

The prokaryotic beta serine recombinase (beta-rec) catalyzes site-specific recombination between two directly oriented six sites (93 bp) in mammalian cells, both in episomal and in chromosomally integrated substrates. The beta-rec/six exclusive intramolecular site-specific recombination (SSR) system has been proposed as a suitable approach when several independently controlled recombination events are needed in a single cell. Here we explored the use of the beta-rec/six system for selective induction of genome-targeted modifications. We generated and analyzed mouse transgenic lines (Tgbeta) expressing beta-rec under the control of the Lck promoter. beta-rec activity was demonstrated, and there was no evidence of alterations to thymic or peripheral T cell development. We developed two transgenic mouse lines harboring different target sequences (Tgrec and KOsix) and analyzed the effect of beta-rec expression on these animals. The results indicate that the beta-rec/six SSR system is functional for in vivo gene-targeting applications.