Par6G suppresses cell proliferation and is targeted by loss-of-function mutations in multiple cancers.

Differentiated epithelial structure communicates with individual constituent epithelial cells to suppress their proliferation activity. However, the pathways linking epithelial structure to cessation of the cell proliferation machinery or to unscheduled proliferation in the context of tumorigenesis are not well defined. Here we demonstrate the strong impact of compromised epithelial integrity on normal and oncogenic Myc-driven proliferation in three-dimensional mammary epithelial organoid culture. Systematic silencing of 34 human homologs of Drosophila genes, with previously established functions in control of epithelial integrity, demonstrates a role for human genes of apico-basal polarity, Wnt and Hippo pathways and actin dynamics in regulation of the size, integrity and cell proliferation in organoids. Perturbation of these pathways leads to diverse functional interactions with Myc: manifested as a RhoA-dependent synthetic lethality and Par6-dependent effects on the cell cycle. Furthermore, we show a role for Par6G as a negative regulator of the phosphatidylinositol 3'-kinase/phosphoinositide-dependent protein kinase 1/Akt pathway and epithelial cell proliferation and evidence for frequent inactivation of Par6G gene in epithelial cancers. The findings demonstrate that determinants of epithelial structure regulate the cell proliferation activity via conserved and cancer-relevant regulatory circuitries, which are important for epithelial cell cycle restriction and may provide new targets for therapeutic intervention.

Asymptomatic De Novo Inflammatory Bowel Disease Late After Liver Transplantation for Primary Sclerosing Cholangitis: A Case Report.

Guidelines recommend colonoscopy screening for possible asymptomatic inflammatory bowel disease (IBD) in all patients diagnosed with primary sclerosing cholangitis (PSC). PSC-IBD warrants regular dysplasia-surveillance colonoscopy. However, no consensus exists regarding follow-up colonoscopy in PSC patients without IBD who remain asymptomatic. We describe a 43-year-old female who had undergone liver transplantation (LT) due to advanced PSC. Previous colonoscopies had been normal. The post-transplantation course was uneventful, with no rejections and signs of PSC recurrence. Immunosuppression was by tacrolimus monotherapy. She was asymptomatic with normal inflammation markers. A protocol colonoscopy, performed as general dysplasia surveillance 8 years post-transplantation, revealed mucopurulent-covered small superficial ulcerations and erythema diffusely distributed from the cecal to sigmoid colon with intervening normal mucosa and rectal sparing. Histologic examination showed patchy chronic colitis with crypt architectural distortion and mild-moderate inflammation activity. Infection samples were negative. Findings complied with de novo IBD, type unclassified. In conclusion, the link between PSC and clinically silent IBD may manifest after the PSC diagnosis and even several years after LT. Given the increased colorectal cancer risk associated with PSC, IBD, and LT, repeat colonoscopy might be warranted in PSC patients without IBD at initial assessment, and also after LT.

ImatraNMR: novel software for batch integration and analysis of quantitative NMR spectra.

Quantitative NMR spectroscopy is a useful and important tool for analysis of various mixtures. Recently, in addition of traditional quantitative 1D (1)H and (13)C NMR methods, a variety of pulse sequences aimed for quantitative or semiquantitative analysis have been developed. To obtain actual usable results from quantitative spectra, they must be processed and analyzed with suitable software. Currently, there are many processing packages available from spectrometer manufacturers and third party developers, and most of them are capable of analyzing and integration of quantitative spectra. However, they are mainly aimed for processing single or few spectra, and are slow and difficult to use when large numbers of spectra and signals are being analyzed, even when using pre-saved integration areas or custom scripting features. In this article, we present a novel software, ImatraNMR, designed for batch analysis of quantitative spectra. In addition to capability of analyzing large number of spectra, it provides results in text and CSV formats, allowing further data-analysis using spreadsheet programs or general analysis programs, such as Matlab. The software is written with Java, and thus it should run in any platform capable of providing Java Runtime Environment version 1.6 or newer, however, currently it has only been tested with Windows and Linux (Ubuntu 10.04). The software is free for non-commercial use, and is provided with source code upon request.

Quantitative (13)C NMR spectroscopy using refocused constant-time INEPT, Q-INEPT-CT.

Quantitative NMR spectroscopy is a useful tool for the analysis of various mixtures. Usually (1)H NMR is used for quantitative measurements, but in many cases the better signal dispersion offered by (13)C NMR is beneficial. However, the low natural abundance of (13)C and long T(1) relaxation times make the acquisition of quantitative (13)C spectra with adequate signal-to-noise ratio time-consuming. The use of polarization transfer experiments such as DEPT or INEPT can offer improved signal intensity and faster repetition rate, but yield non-quantitative results. In this paper we present a pulse sequence based on constant-time INEPT, Q-INEPT-CT, which is capable of producing quantitative carbon spectra with better sensitivity and/or in less time than traditional quantitative (13)C. Additionally, the constant length of the sequence means that signal loss due to relaxation effects can be relatively easily corrected. Thus, the presented sequence is a valuable tool when quantitative carbon data is required quickly and/or low-concentration samples are involved.

Contributions of climate, leaf area index and leaf physiology to variation in gross primary production of six coniferous forests across Europe: a model-based analysis.

Gross primary production (GPP) is the primary source of all carbon fluxes in the ecosystem. Understanding variation in this flux is vital to understanding variation in the carbon sink of forest ecosystems, and this would serve as input to forest production models. Using GPP derived from eddy-covariance (EC) measurements, it is now possible to determine the most important factor to scale GPP across sites. We use long-term EC measurements for six coniferous forest stands in Europe, for a total of 25 site-years, located on a gradient between southern France and northern Finland. Eddy-derived GPP varied threefold across the six sites, peak ecosystem leaf area index (LAI) (all-sided) varied from 4 to 22 m(2) m(-2) and mean annual temperature varied from -1 to 13 degrees C. A process-based model operating at a half-hourly time-step was parameterized with available information for each site, and explained 71-96% in variation between daily totals of GPP within site-years and 62% of annual total GPP across site-years. Using the parameterized model, we performed two simulation experiments: weather datasets were interchanged between sites, so that the model was used to predict GPP at some site using data from either a different year or a different site. The resulting bias in GPP prediction was related to several aggregated weather variables and was found to be closely related to the change in the effective temperature sum or mean annual temperature. High R(2)s resulted even when using weather datasets from unrelated sites, providing a cautionary note on the interpretation of R(2) in model comparisons. A second experiment interchanged stand-structure information between sites, and the resulting bias was strongly related to the difference in LAI, or the difference in integrated absorbed light. Across the six sites, variation in mean annual temperature had more effect on simulated GPP than the variation in LAI, but both were important determinants of GPP. A sensitivity analysis of leaf physiology parameters showed that the quantum yield was the most influential parameter on annual GPP, followed by a parameter controlling the seasonality of photosynthesis and photosynthetic capacity. Overall, the results are promising for the development of a parsimonious model of GPP.

Predicting the decline in daily maximum transpiration rate of two pine stands during drought based on constant minimum leaf water potential and plant hydraulic conductance.

The effect of drought on forest water use is often estimated with models, but comprehensive models require many parameters, and simple models may not be sufficiently flexible. Many tree species, Pinus species in particular, have been shown to maintain a constant minimum leaf water potential above the critical threshold for xylem embolism during drought. In such cases, prediction of the relative decline in daily maximum transpiration rate with decreasing soil water content is relatively straightforward. We constructed a soil-plant water flow model assuming constant plant conductance and daily minimum leaf water potential, but variable conductance from soil to root. We tested this model against independent data from two sites: automatic shoot chamber data and sap flow measurements from a boreal Scots pine (Pinus sylvestris L.) stand; and sap flow measurements from a maritime pine (Pinus pinaster Ait.) stand. To focus on soil limitations to water uptake, we expressed daily maximum transpiration rate relative to the rate that would be obtained in wet soil with similar environmental variables. The comparison was successful, although the maritime pine stand showed carry-over effects of the drought that we could not explain. For the boreal Scots pine stand, daily maximum transpiration was best predicted by water content of soil deeper than 5 cm. A sensitivity analysis revealed that model predictions were relatively insensitive to the minimum leaf water potential, which can be accounted for by the importance of soil resistance of drying soil. We conclude that a model with constant plant conductance and minimum leaf water potential can accurately predict the decline in daily maximum transpiration rate during drought for these two pine stands, and that including further detail about plant compartments would add little predictive power, except in predicting recovery from severe drought.

Summary models for light interception and light-use efficiency of non-homogeneous canopies.

The application of detailed models of canopy photosynthesis rely on the estimation of attenuation of light in the canopy. This attenuation is readily estimated with the Lambert-Beer law when the canopy is homogeneous. In reality, forest canopies are far from homogeneous, and this has led to the use of detailed light extinction models that account for grouping of foliage between and within trees. Because such models require detailed parameterization and fine resolution inputs, they are impractical in larger-scale applications. Thus, there is interest in simplified models that can be readily parameterized. We developed two equations that can be used to estimate mean annual light interception by single unshaded trees and by stands of Poisson distributed trees. Interception by single trees is a function of crown surface area, the ratio of leaf area to crown surface area, the extinction coefficient in a homogeneous canopy--which can be determined separately--and one empirical parameter that depends on the mean solar angle. The summary model was tested against a detailed model of interception, and showed good agreement, although with slight bias. The results showed that crown surface area is a good summary variable for crown size and shape, because errors are independent of crown shape (ellipsoids, cones and height:width ratios). We also tested whether canopy photosynthesis is proportional to light interception across canopies differing in structure and leaf area index, and found that light-use efficiency is influenced by canopy structure. The model is useful in larger-scale applications because it can be parameterized with available data without the need for additional empirical parameters. It can also be used to study the effect of stand structure on mean annual light interception and productivity.

Acute infections, infection pressure, and atopy.

BACKGROUND: During the recent years, a new theory postulating that lack of early childhood infections would increase the prevalence rate of allergies has rapidly gained momentum. This hygiene hypothesis has been widely disseminated to the general public and it has been suggested that vaccinations would accordingly indirectly increase rates of atopy. We thus investigated associations between acute infections, infection pressure (i.e. number of daily child contacts) and atopy in one of the largest population-based medical surveys ever published in the medical literature. METHODS: Almost all Finns born between 1976 and 1984 and a sample of older teenagers aged up to 19 years (n=5 47 190) were vaccinated and questioned to establish clinical history of mumps and rubella and manifestations of atopy (rhinoconjunctivitis, eczema, and asthma) in 1982-1986. A subsample (n=37 733) including all those subjects who were vaccinated during the first 2 months of the measles, mumps, and rubella (MMR) programme were also queried information about upper respiratory infections (URIs) and infection pressure. Crude and adjusted prevalence ratios of atopy among those with infectious disease history compared with those without it were calculated. RESULTS: The risk of URI and a history of mumps and rubella increased with the number of daily contacts. This association was apparent especially among the youngest subjects with regard to URIs whereas the proportion with histories of mumps and rubella increased with increasing infection pressure more clearly among the 6-year-olds. Atopy was not associated with daily child contacts among pre-schoolers. Children with histories of repeated URIs and MMR diseases had substantially more atopy than those with lower URI or MMR disease rates. CONCLUSIONS: Atopic subjects seem to be especially prone to clinically apparent acute respiratory tract infections, and might be in particular need of protection by immunizations. This study does not support the idea that the prevalence of atopy in affluent countries would be affected from disappearing respiratory tract infections.

Cortical activity elicited by isolated vowels and diphthongs.

Cortical activity underlying speech perception has been studied mostly by using isolated vowels with constant formant frequencies. Speech, however, is characterized by formant transitions whereby formant frequencies change as a function of time. We used magnetoencephalography (MEG) to investigate cortical activity elicited by isolated vowels and diphthongs containing formant transitions. Ten subjects were presented with two isolated vowels /a/ and /u/ and diphthongs /au/ and /ua/. Stimulus duration was 200 ms, and the diphthongs started and ended with a 50-ms constant-formant period and included a 100-ms linear transition period. Apart from studying the auditory N100m response, we examined subsequent brain activity in a 500-ms poststimulus time window, as the transitions were expected to elicit activity also in later stages of cognitive processing. All the stimuli elicited prominent N100m responses. Thereafter, both the isolated vowels and diphthongs elicited sustained brain activity lasting up to 500 ms. The present observations indicate that identification of the speech sounds as well as changes in their identity are reflected in the auditory N100m. Notably, the stimuli appeared to elicit left-hemispheric activity resembling the N400, typically obtained by using more complicated speech stimuli such as words and sentences.

The auditory n100m response reflects changes in speech fundamental frequency.

We studied the cortical activation underlying perception of variations in speech fundamental frequency (F0) as indexed by the amplitude, latency and source location of the auditory N100m response registered with magnetoencephalography (MEG). Ten subjects were presented with Finnish vowels with either a constant or an ascending/descending F0. We found that the human auditory cortex is sensitive to these time-varying changes in the F0 of speech: vowels with a constant F0 elicited more prominent N100m responses than did vowels with ascending or descending changes in F0. These results suggest that the speech-related behavior of the N100m arises out of cortical sensitivity to variations in the F0 and its harmonics which underlie the perception of pitch and intonation. The present observations are interpreted in terms of the interrelatedness of speech production and perception.

Periodic glottal excitation and formant frequencies in the perception of vowels.

Voiced speech is created by the fluctuating vocal folds generating the glottal pulseform. This excitation signal is the source of the speech fundamental frequency and its harmonic integer multiples. Periodic glottal excitation is required for the elicitation of speech-specific cortical processes indexed by the auditory N100m response. Here, we studied the cortical processing underlying the perception of the vowels /a/ and /u/ produced using normal and aperiodic phonation. The behavior of the N100m, registered with magnetoencephalography (MEG), was studied in 10 subjects. The amplitude and latency of the N100m as well as the center of gravity of the activated cortical areas varied as a function of stimulus periodicity. Further, the presence of glottal excitation had differential effects on the latency of the N100m elicited by the vowels /a/ and /u/. Thus, changes affecting the perceptual quality of speech signals without changing their phonetic content modify the dynamics of human auditory cortex.

The ratio of NPP to GPP: evidence of change over the course of stand development.

Using Scots pine (Pinus sylvestris L.) in Fenno-Scandia as a case study, we investigate whether net primary production (NPP) and maintenance respiration are constant fractions of gross primary production (GPP) as even-aged mono-specific stands progress from initiation to old age. A model of the ratio of NPP to GPP is developed based on (1) the classical model of respiration, which divides total respiration into construction and maintenance components, and (2) a process-based model, which derives respiration from processes including construction, nitrate uptake and reduction, ion uptake, phloem loading and maintenance. Published estimates of specific respiration and production rates, and some recent measurements of components of dry matter in stands of different ages, are used to quantify the two approaches over the course of stand development in an average environment. Both approaches give similar results, showing a decrease in the NPP/GPP ratio with increasing tree height. In addition, we show that stand-growth models fitted under three different sets of assumptions-(i) annual specific rates of maintenance respiration of sapwood (mW) and photosynthesis (sC) are constant; (ii) m(W) is constant, but sC decreases with increasing tree height; and (iii) total maintenance respiration is a constant fraction of GPP and s(C) decreases with increasing tree height-can lead to nearly identical model projections that agree with empirical observations of NPP and stand-growth variables. Remeasurements of GPP and respiration over time in chronosequences of stands may be needed to discern which set of assumptions is correct. Total (construction + maintenance) sapwood respiration per unit mass of sapwood (kg C (kg C year)-1) decreased with increasing stand age, sapwood stock, and average tree height under all three assumptions. However, total sapwood respiration (kg C (ha year)-1) increased over the course of stand development under (i) and (ii), contributing to a downward trend in the time course of the NPP/GPP ratio after closure. A moderate decrease in mW with increasing tree height or sapwood cross-sectional area had little effect on the downward trend. On the basis of this evidence, we argue that a significant decline in the NPP/GPP ratio with tree size or age seems highly probable, although the decline may appear insignificant over some segments of stand development. We also argue that, because stand-growth models can give correct answers for the wrong reasons, statistical calibration of such models should be avoided whenever possible; instead, values of physiological parameters should come from measurements of the physiological processes themselves.

Visual attention to words of native versus later acquired languages: a magnetoencephalographic study in humans.

We recorded evoked magnetic fields while short words were visually presented in different languages with an oddball paradigm. The task was to count how many words were in a target language when most of the words were in another language and there were also non-target deviants in a third language. When native words (Finnish) were targets, they evoked a selection response at the latency of 300-600 ms. However, when the task was to count non-native words among native standards, in addition to the targets, also the non-target foreign words evoked the selection response. These results may reflect differences in the selection process for native versus non-native words brought about by different proficiency levels of the languages.

The fixation properties of carbon fiber-reinforced liquid crystalline polymer implant in bone: an experimental study in rabbits.

A novel composite material with ultra-high strength and a low elastic modulus called carbon fiber-reinforced liquid crystalline polymer (LCP/CF) has been developed. We studied the fixation properties of an intramedullary LCP/CF rod in rabbit bone. The medullary canals of both femora were reamed with a drill 3.2 mm in diameter starting from the trochanteric fossa in eleven New Zealand White rabbits weighing on average 4.8 kg. A smooth LCP/CF rod 3.2 mm in diameter and 50 mm in length was introduced into the medullary canal of both femora. The follow-up intervals were 0, 6, 12, and 52 weeks. The upper part of the harvested femora was cut into two pieces, each 25 mm in length. A mechanical push-out test was performed within 48 h to determine bone-implant interface attachment strength in the proximal (cancellous) and distal (cortical) locations. The mean push-out strength values at 0, 6, 12, and 52 weeks were 61, 250, 382, and 612 KPa in the cancellous location and 0, 32, 41, and 68 KPa in the cortical location, respectively. The strength of the bone/implant interface appeared to be quite low, similar to other uncoated or nonporous implants, but it was found to increase with time.

Magnetoencephalographic (MEG) localization of the auditory N400m: effects of stimulus duration.

The effects of stimulus duration on the elicitation and equivalent current dipole (ECD) localization of the auditory N400(m) were studied in two subject groups, either familiar or unfamiliar with Finnish language, using a sentence-processing paradigm with incongruent ending words of either short or long duration. Long-duration words elicited a broad response at around 400 ms, the generator location(s) of which could not be reliably determined using ECD estimation. In contrast, short-duration words elicited a sharp, strong-amplitude response at about 400 ms latency and it's source location could be reliably determined as being in the vicinity of auditory cortex. Subjects unfamiliar with the Finnish language elicited no response at the 400 ms range. Thus, the use of short-duration words appears to be an important prerequisite for the elicitation and localization of N400m. The differential amplitude behaviour of the N400m between the two subject groups further suggests that comprehension of the semantic content of the speech message is also required.

Fine root biomass of Scots pine stands differing in age and soil fertility in southern Finland.

The biomass of small and large fine roots (

Fixation of distal femoral osteotomy with an intramedullary rod: early failure of carbon fibre composite implant in rabbits.

A novel composite material with an ultra-high strength and a low elastic modulus, comprising a carbon fibre reinforced liquid crystalline polymer (LCP/CF) has been developed. An experimental osteotomy of the distal femur in nineteen rabbits weighing on average 4.8 (3.7-6.3) kg was fixed with an intramedullary LCP/CF rod of 3.2 mm in diameter and 50 mm in length. The initial mechanical properties of the rods had a mean shear strength of 180 MPa, a flexural strength of 450 MPa, and a flexural modulus of 40 GPa. The rods were implanted for periods of 3, 6, 12, 24, and 52 weeks. The healing of the osteotomy was analyzed by radiographic, histological, microradiographic, and oxytetracycline fluorescence studies. The strength retention of the LCP/CF rods was measured by mechanical testing. Solid union of the osteotomy was seen within 6 weeks. The implants retained their original strength properties up to 52 weeks. In three rabbits, a non-union with granulation tissue and carbon fibre particles was noticed at the osteotomy site, where disruption of the implant surface was seen at the level of the osteotomy. Further studies with a special interest in the fabrication process of the LCP/CF-implants are needed.

Phospholipase A2 activity in body fluids and pancreatic tissue in patients with acute necrotising pancreatitis.

OBJECTIVE: To measure pancreatic and non-pancreatic phospholipase A2 activity in human acute necrotising pancreatitis. DESIGN: Prospective study. SETTING: University hospital, Finland. SUBJECTS: 20 patients with acute necrotising pancreatitis. INTERVENTIONS: Serum and urine samples were taken daily for a week and fluid from peritoneal lavage for six days after admission. Samples from the pleural cavity were taken from patients in whom pleural drainage was considered necessary. Pancreatic tissue was recovered from the patients who were operated on for acute pancreatitis or for pancreatic tumour. MAIN OUTCOME MEASURES: Serum phospholipase A2, amylase, and lipase activities. RESULTS: Serum phospholipase A2 activity increased up to eightfold, 25.0 (5.4) IU/L (n = 20, range 9.0-77 IU/L) (reference value <3 IU/L) and remained high during the first week, whereas serum amylase and lipase returned to the reference range during the first four days. The maximal phospholipase A2 activity in urine was 4.5 IU/L, in the fluid from peritoneal lavage 16.9 IU/L, and in the fluid from the pleural cavity 37.0 IU/L. Phospholipase A2 activity in necrotic pancreatic tissue ranged from 0.25 to 5.70 IU/g and in normal pancreatic tissue from 9.85 to 15.0 IU/g. Preincubation at 60 degrees C showed non-pancreatic phospholipase A2 activity predominated in serum, whereas part of the enzyme activity in the fluids from pleural cavity and peritoneal lavage proved to be of pancreatic derivation. CONCLUSIONS: The results suggest a role for both pancreatic and non-pancreatic phospholipase A2 in acute pancreatitis. Preincubation at 60 degrees C proved useful in the differentiation between pancreatic and non-pancreatic phospholipase A2 activity.

Fixation of femoral shaft osteotomy with an intramedullary composite rod: an experimental study on dogs with a two-year follow-up.

A novel composite material with an ultra-high strength and a low elastic modulus called carbon fibre-reinforced liquid crystalline polymer (LCP/CF) has been developed. An experimental diaphyseal osteotomy of the proximal femur in fourteen Beagle dogs was fixed with an intramedullary LCP/CF rod of 4.5 mm in diameter and 80 mm in length. The radiological follow-up intervals were 1, 3, 6, 12, 24, 52, and 104 weeks. Five dogs were killed at 1 year and three dogs at 2 years for histological studies; six dogs were retained for longer follow-up. Radiographs showed an uncomplicated healing of the diaphyseal osteotomy with an external callus formation in all dogs in 12 weeks. Histological analysis revealed a benign host tissue response with few inflammatory cells. Both bone and fibrous tissue were seen at the LCP/CF-host tissue interface. The cross-sectional cortical area of the operated femur was slightly greater than that of the control femur in the 2-year follow-up. LCP/CF showed promising properties for high-load applications.