What can computed tomography and magnetic resonance imaging tell us about ventilation?

This review provides a summary of pulmonary functional imaging approaches for determining pulmonary ventilation, with a specific focus on multi-detector x-ray computed tomography and magnetic resonance imaging (MRI). We provide the important functional definitions of pulmonary ventilation typically used in medicine and physiology and discuss the fact that some of the imaging literature describes gas distribution abnormalities in pulmonary disease that may or may not be related to the physiological definition or clinical interpretation of ventilation. We also review the current state-of-the-field in terms of the key physiological questions yet unanswered related to ventilation and gas distribution in lung disease. Current and emerging imaging research methods are described, including their strengths and the challenges that remain to translate these methods to more wide-spread research and clinical use. We also examine how computed tomography and MRI might be used in the future to gain more insight into gas distribution and ventilation abnormalities in pulmonary disease

Analysis of Regional Mechanics in Canine Lung Injury Using Forced Oscillations and 3D Image Registration

Acute lung injury is characterized by heterogeneity of regional mechanical properties, which is thought to be correlated with disease severity. The feasibility of using respiratory input impedance ($Z_{rs}$) and computed tomographic (CT) image registration for assessing parenchymal mechanical heterogeneity was evaluated. In six dogs, measurements of ($Z_{rs}$) before and after oleic acid injury at various distending pressures were obtained, followed by whole lung CT scans. Each ($Z_{rs}$) spectrum was fit with a model incorporating variable distributions of regional compliances. CT image pairs at different inflation pressures were matched using an image registration algorithm, from which distributions of regional compliances from the resulting anatomic deformation fields were computed. Under baseline conditions, average model compliance decreased with increasing inflation pressure, reflecting parenchymal stiffening. After lung injury, these average compliances decreased at each pressure, indicating derecruitment, alveolar flooding, or alterations in intrinsic tissue elastance. However, average compliance did not change as inflation pressure increased, consistent with simultaneous recruitment and strain stiffening. Image registration revealed peaked distributions of regional compliances, and that small portions of the lung might undergo relative compression during inflation. The authors conclude that assessments of lung function using ($Z_{rs}$) combined with the structural alterations inferred from image registration provide unique but complementary information on the mechanical derangements associated with lung injury

Vitamins D and K as Factors Associated with Osteopathy in Chronic Pancreatitis. A Prospective Multicentre Study (P-BONE Study)

Background: Osteopathy is common in patients with chronic pancreatitis (CP), but previous studies carry several limitations. Vitamin K is essential for bone metabolism, but its role in this setting has never been investigated. Our aim is to assess the prevalence of osteoporosis and osteopenia in CP patients, and to investigate the association between osteopathy and CP features and nutritional parameters, especially vitamin D and K levels. Methods: Multicentre cross-sectional study on CP patients diagnosed according to M-ANNHEIM criteria. Bone density was evaluated by dual-energy X-ray absorptiometry and pancreatic function by faecal elastase. Nutritional evaluation included vitamin D and vitamin K. Differences between patients with or without osteopathy were evaluated. The association between investigated variables and bone density were analysed with logistic regression analysis. Results: In total, 211 CP patients were enrolled at eight Centres (67% men; mean age 60). In total, 18% had advanced-marked CP, 56% suffered from pancreatic exocrine insufficiency and disease aetiology was alcoholic in 43%. Vitamin D and K were deficient in 56% and 32%, respectively. Osteopenia was diagnosed in 42% and osteoporosis in 22%. In the multivariate analysis, female sex (OR 2.78), age (OR 1.07 per year) and higher BMI (OR 0.84) were associated with the presence of osteoporosis. In male patients, the only factor associated with osteoporosis was vitamin K deficiency (OR 4.23). Conclusion: The present data confirm a high rate of osteopathy in CP patients and highlight the relevance of vitamin K deficiency as only factor associated with osteoporosis in male patients for the first time

Tree rings of Scots pine (Pinus sylvestris L.) as a source of information about past climate in northern Poland

Scots pine (Pinus sylvestris) is a very common tree in Polish forests, and therefore was widely used as timber. A relatively large amount of available wood allowed a long-term chronology to be built up and used as a source of information about past climate. The analysis of reconstructed indexed values of mean temperature in 51-year moving intervals allowed the recognition of the coldest periods in the years 1207–1346, 1383–1425, 1455–1482, 1533–1574, 1627–1646, and 1694–1785. The analysis of extreme wide and narrow rings forms a complementary method of examining climatic data within tree rings. The tree ring widths, early wood and late wood widths of 16 samples were assessed during the period 1581–1676. The most apparent effect is noted in the dry summer of 1616. According to previous research and our findings, temperature from February to March seems to be one of the most stable climatic factors which influenced pine growth in Poland. Correlation coefficients in the calibration and validation procedure gave promising results for temperature reconstruction from the pine chronology

Purification, crystallization and preliminary X-ray analysis of adenylosuccinate synthetase from the fungal pathogen Cryptococcus neoformans

With increasingly large immunocompromised populations around the world, opportunistic fungal pathogens such as Cryptococcus neoformans are a growing cause of morbidity and mortality. To combat the paucity of antifungal compounds, new drug targets must be investigated. Adenylosuccinate synthetase is a crucial enzyme in the ATP de novo biosynthetic pathway, catalyzing the formation of adenylosuccinate from inosine monophosphate and aspartate. Although the enzyme is ubiquitous and well characterized in other kingdoms, no crystallographic studies on the fungal protein have been performed. Presented here are the expression, purification, crystallization and initial crystallographic analyses of cryptococcal adenylosuccinate synthetase. The crystals had the symmetry of space group P2(1)2(1)2(1) and diffracted to 2.2 angstrom resolution

The role of endothelin-1 in hyperoxia-induced lung injury in mice

BACKGROUND: As prolonged hyperoxia induces extensive lung tissue damage, we set out to investigate the involvement of endothelin-1 (ET-1) receptors in these adverse changes. METHODS: Experiments were performed on four groups of mice: control animals kept in room air and a group of mice exposed to hyperoxia for 60 h were not subjected to ET-1 receptor blockade, whereas the dual ETA/ETB-receptor blocker tezosantan (TEZ) was administered via an intraperitoneal pump (10 mg/kg/day for 6 days) to other groups of normal and hyperoxic mice. The respiratory system impedance (Zrs) was measured by means of forced oscillations in the anesthetized, paralyzed and mechanically ventilated mice before and after the iv injection of ET-1 (2 μg). Changes in the airway resistance (Raw) and in the tissue damping (G) and elastance (H) of a constant-phase tissue compartment were identified from Zrs by model fitting. RESULTS: The plasma ET-1 level increased in the mice exposed to hyperoxia (3.3 ± 1.6 pg/ml) relative to those exposed to room air (1.6 ± 0.3 pg/ml, p < 0.05). TEZ administration prevented the hyperoxia-induced increases in G (13.1 ± 1.7 vs. 9.6 ± 0.3 cmH(2)O/l, p < 0.05) and H (59 ± 9 vs. 41 ± 5 cmH(2)O/l, p < 0.05) and inhibited the lung responses to ET-1. Hyperoxia decreased the reactivity of the airways to ET-1, whereas it elevated the reactivity of the tissues. CONCLUSION: These findings substantiate the involvement of the ET-1 receptors in the physiopathogenesis of hyperoxia-induced lung damage. Dual ET-1 receptor antagonism may well be of value in the prevention of hyperoxia-induced parenchymal damage

Scientific merits and analytical challenges of tree-ring densitometry

R.W. was supported by NERC grant NE/K003097/1.X-ray microdensitometry on annually-resolved tree-ring samples has gained an exceptional position in last-millennium paleoclimatology through the maximum latewood density parameter (MXD), but also increasingly through other density parameters. For fifty years, X-ray based measurement techniques have been the de facto standard. However, studies report offsets in the mean levels for MXD measurements derived from different laboratories, indicating challenges of accuracy and precision. Moreover, reflected visible light-based techniques are becoming increasingly popular and wood anatomical techniques are emerging as a potentially powerful pathway to extract density information at the highest resolution. Here we review the current understanding and merits of wood density for tree-ring research, associated microdensitometric techniques, and analytical measurement challenges. The review is further complemented with a careful comparison of new measurements derived at 17 laboratories, using several different techniques. The new experiment allowed us to corroborate and refresh ?long-standing wisdom?, but also provide new insights. Key outcomes include; i) a demonstration of the need for mass/volume based re-calibration to accurately estimate average ring density; ii) a substantiation of systematic differences in MXD measurements that cautions for great care when combining density datasets for climate reconstructions; and iii) insights into the relevance of analytical measurement resolution in signals derived from tree-ring density data. Finally, we provide recommendations expected to facilitate future inter-comparability and interpretations for global change research.Publisher PDFPeer reviewe

Diagnosis and treatment of thyroid cancer in children in the multicenter analysis in Poland for PPGGL

Introduction: Differentiated thyroid carcinoma (DTC) in children presents different biological behavior in comparison to adults. Authors presents preliminary results of multicenter analysis concerning incidence, diagnostics and treatment of DTC in children. Material and methods: The study is a retrospective analysis of 107 pediatric patients from 14 academic centers based on the data from 2000 to 2005 obtained by questionnaire in hospitals involved in the treatment of DTC in children. Results: Papillary thyroid cancer was diagnosed in 83 children, follicular thyroid cancer in 10 children and medullary thyroid cancer in 14 children. Incidence of DTC in children was estimated between 18 and 23 cases per year. The biggest group of patients consisted of children between 11 and 15 years of age, with girls to boys ratio 3.3 : 1. Clinically DTC in children presented most often as solitary thyroid nodule. Cervical lymphadenopathy was observed in 42% of patients. Intraoperative verification indicated metastatic nodes in 50% of children. Low stage DTC predominated (T1 in 36% and T2 in 26% of children). One step surgery was performed in 65% of children with DTC, two step surgery in 25% of patients. I131 therapy was undertaken in 80% of children. Lung metastases were indicated in post therapeutic studies in 14% of children with DTC. Prophylactic thyroidectomies were performed in 79% of children in the group of patients with MTC and RET gene mutations. Conclusions: The necessity of introduction of unified therapeutic standard in children with DTC in Poland is underlined.Wstęp: Zróżnicowane raki tarczycy (DTC, differentiated thyroid carcinoma) występują u dzieci rzadko. Większość przypadków wykrywanych jest w wieku 11-17 lat. W odróżnieniu od dorosłych DTC u dzieci prezentują odmienne zachowanie biologiczne. Mała liczba przypadków DTC w poszczególnych ośrodkach oraz względnie łagodny ich przebieg utrudniają ocenę występowania i leczenia DTC u dzieci w Polsce, uzależniając ją od wysiłków włożonych w uzyskanie rzetelnych danych. Autorzy przedstawiają wstępne wyniki analizy wieloośrodkowej dotyczące występowania, diagnostyki i leczenia DTC u dzieci. Materiał i metody: Podjęte badania są retrospektywną analizą obejmującą lata 2000-2005, opartą na danych z historii chorób uzyskanych z ankiet rozesłanych do ośrodków dla dzieci i dorosłych podejmujących leczenie DTC. Do analizy zgłoszono 107 pacjentów z 14 ośrodków akademickich w Polsce. Analizie poddano wiek i płeć dzieci z DTC, wielkość i lokalizację zmian w tarczycy, sposoby rozpoznawania DTC, rodzaje i zakres wykonywanych zabiegów operacyjnych oraz leczenie uzupełniające izotopem J131. Wyniki: Raka brodawkowatego stwierdzono u 83 dzieci, pęcherzykowego u 10 dzieci, a rdzeniastego u 14 dzieci. Częstość występowania DTC u dzieci w Polsce wahała się między 18 a 23 przypadkami rocznie. W województwach: mazowieckim i połączonych wielkopolskim i lubuskim wykazano w okresie 2000-2005 wyższą (24 i 25) częstość występowania DTC, w pozostałych województwach wykazywano od 2 do 10 przypadków DTC. Największą grupę pacjentów stanowiły dzieci w wieku 11-15 lat, a stosunek dziewcząt do chłopców wynosił 3,3 : 1. Klinicznie DTC prezentowały się najczęściej jako pojedyncze guzki tarczycy. Limfadenopatię szyjną w badaniu klinicznym stwierdzono u 42% pacjentów, a śródoperacyjnie u 50% dzieci. U większości pacjentów dominowały niższe stopnie zaawansowania DTC (T1 u 36% i T2 u 26% dzieci). Operacje jednoetapowe wykonano u 65% dzieci, operacje dwuetapowe u 25% dzieci, a profilaktyczne tyreoidektomie u 79% dzieci z grupy pacjentów z rakiem rdzeniastym tarczycy (MTC, medullary thyroid cancinoma) i mutacją genu Ret. Leczenie izotopowe J131 podjęto u 80% dzieci. Przerzuty do płuc w scyntygrafii poterapeutycznej wykazano u 14% dzieci z DTC. Wnioski: We wnioskach podkreśla się konieczność wdrożenia na terenie całego kraju ujednoliconego i ocenianego na podstawie obiektywnych przesłanek sposobu postępowania z dziećmi z DTC

No systematic effects of sampling direction on climate-growth relationships in a large-scale, multi-species tree-ring data set

Ring-width series are important for diverse fields of research such as the study of past climate, forest ecology, forest genetics, and the determination of origin (dendro-provenancing) or dating of archaeological objects. Recent research suggests diverging climate-growth relationships in tree-rings due to the cardinal direction of extracting the tree cores (i.e. direction-specific effect). This presents an understudied source of bias that potentially affects many data sets in tree-ring research. In this study, we investigated possible direction-specific growth variability based on an international (10 countries), multi-species (8 species) tree-ring width network encompassing 22 sites. To estimate the effect of direction-specific growth variability on climate-growth relationships, we applied a combination of three methods: An analysis of signal strength differences, a Principal Component Gradient Analysis and a test on the direction-specific differences in correlations between indexed ring-widths series and climate variables. We found no evidence for systematic direction-specific effects on tree radial growth variability in high-pass filtered ring-width series. In addition, direction-specific growth showed only marginal effects on climate-growth correlations. These findings therefore indicate that there is no consistent bias caused by coring direction in data sets used for diverse dendrochronological applications on relatively mesic sites within forests in flat terrain, as were studied here. However, in extremely dry, warm or cold environments, or on steep slopes, and for different life-forms such as shrubs, further research is advisable.</p