We determined decadal changes in soil carbon (C) and nitrogen (N) due to different irrigation regimes and phosphorus fertilization of pastures. Archived soil samples (0–75 mm) collected annually from ...two long‐term trials in New Zealand were analyzed for %C and %N from three P input treatments (ranging from 0 to 376 kg superphosphate ha−1 yr−1, 1952–2009) and three irrigation treatments (unirrigated and irrigated when soil moisture content fell below either 10 or 20%, 1959–2002). In the fertilizer trial, soil C increased linearly from 2.7 to 4.2%, and there was no difference in rates of increase in C between treatments, despite much greater aboveground production when P was added. This lack of difference was attributed to higher stocking rates on treatments with higher production, and to the possibility that root inputs (which differed less between treatments) was a more important control of soil C accumulation. Nitrogen (%) was lower in the unfertilized than fertilized treatments due to lower clover N fixation, which was constrained by P availability. Soil C (%) was significantly greater in the unirrigated treatment than the irrigated treatments throughout the trial. Aboveground production was much greater in the irrigated than dryland treatment but root biomass was lower. Irrigation must have increased C and N losses, possibly via increased respiration rates during seasonally dry periods. Our study showed that P fertilizer application did not result in an increase in surface soil C and that flood irrigation resulted in a constrained increase in surface soil C content.
OBJECTIVESEncephalopathy is a common complication of sepsis. This review describes the different pathologic mechanisms that may be involved in its etiology.
DATA SOURCESThe studies described here ...were derived from the database PubMed (http:\\http://www.nlm.nih.gov) and from references identified in the bibliographies of pertinent articles and books. The citations are largely confined to English language articles between 1966 and 1998. Older publications were used if they were of historical significance.
STUDY SELECTIONAll investigations in which any aspect of septic encephalopathy was reported were included. This selection encompasses clinical, animal, and in vitro cell culture work.
DATA EXTRACTIONThe literature cited was published in peer-reviewed clinical or basic science journals or in books.
DATA SYNTHESISContradictions between the results of published studies are discussed.
CONCLUSIONSThe most immediate and serious complication of septic encephalopathy is impaired consciousness, for which the patient may require ventilation. The etiology of septic encephalopathy involves reduced cerebral blood flow and oxygen extraction by the brain, cerebral edema, and disruption of the blood-brain barrier that may arise from the action of inflammatory mediators on the cerebrovascular endothelium, abnormal neurotransmitter composition of the reticular activating system, impaired astrocyte function, and neuronal degeneration. Currently, there is no treatment.
Interstitial cells of Cajal (ICCs) were identified in the intact fixed media of the rabbit portal vein (RPV) using c-kit staining. The following experiments were performed using single cell ...preparations of the enzyme-dispersed vessel. Surviving contacts between the processes of single ICCs and the bodies of smooth muscle cells (SMCs) were observed in electron micrographs and by confocal microscopy. Spontaneous rhythmical Cai oscillations were observed in ICCs after loading with the calcium indicator fluo-3 and were associated with depolarizations of the ICCs recorded by tight-seal patch pipette. To investigate signal transmission from ICCs to SMCs in dispersed cell pairs, or within small surviving fragments of the ICC network, an ICC was stimulated under voltage-clamp, while changes in Cai in the stimulated cell as well as in a closely adjacent SMC or ICCs were monitored using fast x- y confocal imaging of fluo-3 fluorescence. After stimulation of single voltage-clamped ICC by a depolarizing step similar in duration to depolarizations associated with spontaneous Cai oscillations, a depolarization and transient elevation of Cai was observed in a closely adjacent SMCs after a delay of up to 4 seconds. In contrast, signal transmission from ICC to ICC was much faster, the delay being less than 200 ms. These results suggest that the an ICC may, in addition to generating an electrical signal (such as a slow wave) and thereby acting as a pacemaker for vascular SMCs of RPV, also release some unknown diffusible substance, which depolarizes the SMCs.
Vascular interstitial cells (VICs) are non‐contractile cells with filopodia previously described in healthy blood vessels of rodents and their function remains unknown. The objective of this study ...was to identify VICs in human arteries and to ascertain their role. VICs were identified in the wall of human gastro‐omental arteries using transmission electron microscopy. Isolated VICs showed ability to form new and elongate existing filopodia and actively change body shape. Most importantly sprouting VICs were also observed in cell dispersal. RT‐PCR performed on separately collected contractile vascular smooth muscle cells (VSMCs) and VICs showed that both cell types expressed the gene for smooth muscle myosin heavy chain (SM‐MHC). Immunofluorescent labelling showed that both VSMCs and VICs had similar fluorescence for SM‐MHC and αSM‐actin, VICs, however, had significantly lower fluorescence for smoothelin, myosin light chain kinase, h‐calponin and SM22α. It was also found that VICs do not have cytoskeleton as rigid as in contractile VSMCs. VICs express number of VSMC‐specific proteins and display features of phenotypically modulated VSMCs with increased migratory abilities. VICs, therefore represent resident phenotypically modulated VSMCs that are present in human arteries under normal physiological conditions.
It is now established that non‐contractile cells with thin filopodia, also called vascular interstitial cells (VICs), are constitutively present in the media of many, if not all, blood vessels. The ...aim of this study was to determine the type of cell lineage to which arterial VICs belong using immunocytochemical, and real‐time and reverse transcription PCR (RT‐PCR). Using RT‐PCR, we compared gene expression profiles of single VICs and smooth muscle cells (SMCs) freshly dispersed from rat middle cerebral artery. Both VICs and SMCs expressed the SMC marker, smooth muscle myosin heavy chain (SM‐MHC), but did not express fibroblast, pericyte, neuronal, mast cell, endothelial or stem cell markers. Freshly isolated VICs also did not express c‐kit, which is the marker for interstitial cells of Cajal in the gastrointestinal tract. Immunocytochemical labelling of contractile proteins showed that VICs and SMCs expressed SM‐MHC similarly to the same degree, but VICs in contrast to SMCs had decreased expression of α‐SM‐actin and very low or no expression of calponin. Real‐time RT‐PCR was consistent with immunocytochemical experiments and showed that VICs had four times lower gene expression of calponin comparing to SMCs, which may explain VICs’ inability to contract. VICs had greater expression than SMCs of structural proteins such as non‐muscular β‐actin and desmin. The results obtained suggest that VICs represent a subtype of SMCs and may originate from the same precursor as SMCs, but later develop filopodia and a non‐contractile cell phenotype.
This work aimed to establish the lineage of cells similar to the interstitial cells of Cajal (ICC), the arterial ICC‐like (AIL) cells, which have recently been described in resistance arteries, and ...to study their location in the artery wall. Segments of guinea‐pig mesenteric arteries and single AIL cells freshly isolated from them were used. Confocal imaging of immunostained cells or segments and electron microscopy of artery segments were used to test for the presence and cellular localization of selected markers, and to localize AIL cells in intact artery segments. AIL cells were negative for PGP9.5, a neural marker, and for von Willebrand factor (vWF), an endothelial cell marker. They were positive for smooth muscle α‐actin and smooth muscle myosin heavy chain (SM‐MHC), but expressed only a small amount of smoothelin, a marker of contractile smooth muscle cells (SMC), and of myosin light chain kinase (MLCK), a critical enzyme in the regulation of smooth muscle contraction. Cell isolation in the presence of latrunculin B, an actin polymerization inhibitor, did not cause the disappearance of AIL cells from cell suspension. The fluorescence of basal lamina protein collagen IV was comparable between the AIL cells and the vascular SMCs and the fluorescence of laminin was higher in AIL cells compared to vascular SMCs. Moreover, cells with thin processes were found in the tunica media of small resistance arteries using transmis‐sion electron microscopy. The results suggest that AIL cells are immature or phenotypically modulated vascular SMCs constitutively present in resistance arteries.
Activation foils, stacked in a package, together with a spectrum adjustment code are generally the means to characterize the neutron spectrum of a BNCT epithermal neutron beam. When using foil ...stacks, the phenomenon of neutron scattering is appreciably enhanced, especially in an epithermal neutron beam, as compared to a thermal neutron field. Contrary to the conventional idea of the self-shielding effect, self-shielding correction factors in most of the foils in the stack are larger than one. This paper demonstrates a way to correct the complex self-shielding effect using groupwise cross-sections modified for self-shielding, as calculated by the Monte Carlo neutron transport code, MCNP. This methodology can solve the perturbation problems caused by the foil stack applied in an epithermal neutron beam. In this study, the adjusted spectrum of the HB11 epithermal neutron beam, dedicated for BNCT research in Petten, The Netherlands, is utilized and two adjusted spectra are presented with and without the self-shielding correction. The difference between the spectra is highly significant and demonstrates that the self-shielding correction cannot be ignored.
Neutron capture therapy (NCT) is based on the ability of the non-radioactive isotope boron-10 to capture thermal neutrons with very high probability and immediately to release heavy particles with a ...path length of one cell diameter, which in principle allows for tumor cell-selective high-LET particle radiotherapy. This book provides a comprehensive summary of the progress made in NCT in recent years. Individual sections cover all important aspects, including neutron sources, boron chemistry, drugs for NCT, dosimetry, and radiation biology. The use of NCT in a variety of malignancies and also some non-malignant diseases is extensively discussed. NCT is clearly shown to be a promising modality at the threshold of wider clinical application. All of the chapters are written by experienced specialists in language that will be readily understood by all participating disciplines.
Soil microbes and phosphatase enzymes play a critical role in organic soil phosphorus (P) cycling. However, how long‐term P inputs influence microbial P transformations and phosphatase enzyme ...activity under grazed pastures remains unclear. We collected top‐soil (0–75 mm) from a grazed pasture receiving contrasting P inputs (control, 188 kg ha−1 year−1 of single super phosphate SSP, and 376 kg ha−1 year−1 of SSP) for more than 65 years. Olsen P, microbial biomass P, and acid and alkaline phosphatase enzyme activities were measured regularly over a 2‐year period. Pasture dry matter and soil chemical properties were also investigated. Results showed that long‐term P inputs significantly increased pasture dry matter, total N, and the concentrations of NO3––N but significantly decreased soil pH and the concentrations of NH4+–N. Total C was not affected by P fertilization. Although Olsen P significantly increased with increasing long‐term P inputs, microbial biomass P was similar under P fertilized treatments. Long‐term P inputs decreased acid phosphatase activity but increased alkaline phosphatase activity. Microbial biomass P was similar across seasons in the control but decreased in spring and autumn while increased in summer and winter under P fertilized treatments. Acid and alkaline phosphatase activities were significantly affected by season and followed similar seasonal trends being maximum in summer and minimum in winter regardless of P treatment. Correlation and principal component analysis revealed that acid and alkaline phosphatase activities were significantly positively correlated with soil temperature and significantly negatively correlated with soil moisture. In contrast, Olsen P and microbial biomass P were weakly correlated with environmental conditions. The findings of this study highlight the intertwined relationship between organic P cycling and the availability of C and N in soil systems and the need to integrate both soil moisture and temperature in models predicting organic P mineralization, especially in the context of global climate change.
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