CropPol: a dynamic, open and global database on crop pollination

Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved.

The development of a novel functional food: bioactive lipids in yogurts enriched with Aurantiochytrium sp. biomass

Western diets are poor in healthy n3 polyunsaturated fatty acids, such as docosahexaenoic acid. Since microalga Aurantiochytrium sp. is rich in docosahexaenoic acid, a functional food based on lean yogurt and this microalga was tested. This study entailed characterizing the lipid fraction and determining the fatty acid bioaccessibility. The tested yogurts (control and 2% w/w, Aurantiochytrium sp.) had differences. Docosahexaenoic acid was not detected in the control product, but it was the second most important fatty acid in Aurantiochytrium sp. and Aurantiochytrium yogurt, 29.7 ± 0.4% and 18.7 ± 2.0%, respectively. Based on the fatty acid profile only, an amount of 158.7 g of Aurantiochytrium yogurt in wet weight terms would be required to ensure an appropriate intake of healthy fatty acids. Generally, the fatty acid bioaccessibility was not high, remaining below 60-70% in almost all cases. Considering the docosahexaenoic acid bioaccessibility (44 ± 3%), an amount of 360.7 g of Aurantiochytrium yogurt would be advisable. A reasonable dietary prescription would be a daily consumption of 125 ml of Aurantiochytrium yogurt.

Capacitive technologies for highly controlled and personalized electrical stimulation by implantable biomedical systems

Cosurface electrode architectures are able to deliver personalized electric stimuli to target tissues. As such, this technology holds potential for a variety of innovative biomedical devices. However, to date, no detailed analyses have been conducted to evaluate the impact of stimulator architecture and geometry on stimuli features. This work characterizes, for the first time, the electric stimuli delivered to bone cellular tissues during in vitro experiments, when using three capacitive architectures: stripped, interdigitated and circular patterns. Computational models are presented that predict the influence of cell confluence, cosurface architecture, electrodes geometry, gap size between electrodes and power excitation on the stimuli delivered to cellular layers. The results demonstrate that these stimulators are able to deliver osteoconductive stimuli. Significant differences in stimuli distributions were observed for different stimulator designs and different external excitations. The thickness specification was found to be of utmost importance. In vitro experiments using an osteoblastic cell line highlight that cosurface stimulation at a low frequency can enhance osteoconductive responses, with some electrode-specific differences being found. A major feature of this type of work is that it enables future detailed analyses of stimuli distribution throughout more complex biological structures, such as tissues and organs, towards sophisticated biodevice personalization.

Adsorption of H2, O2, H2O, OH and H on monolayer MoS2

Hydrogen and hydrogen-containing gases are commonly used as reductants in chemical vapor deposition growth of MoS₂. Here, we consider the defects resulting from the presence of hydrogen during growth and the resulting electronically active defects. In particular, we find that the interstitial hydrogen defect is a negative-U center with amphoteric donor and acceptor properties. Additionally, we consider the effects of interaction with water and oxygen. The defects are analysed using density functional theory calculations.

Psychophysiological Reactivity in Couples During a Marital Interaction Task

The ability to regulate our own physiological arousal when dealing with the emotional expression of our partner is crucial for satisfactory and stable intimate relationships. In previous physiological studies of marital interactions, researchers have found greater levels of psychophysiological arousal for members of the couple in conflictual interactions in comparison with positive interactions. Past researchers have established that intense and prolonged autonomic and neuroendocrine arousal during marital conflict can have negative consequences for mental and physical health. In this study we examined the physiological reactivity, as measured by skin conductance level, heart rate and cortisol levels, from both partners during a couple's interaction task consisting of a structured conversation about positive and negative aspects of their relationship. Participants were thirty-two heterosexual couples (N = 64) in a committed monogamous relationship with a minimum duration of one year. We found higher heart rate and cortisol levels during negative interaction condition when compared with the positive condition. Skin conductance was higher in the positive interaction condition, when compared with the negative interaction condition. In addition, we found a significant negative association between heart rate variability and autonomic arousal evoked by the interaction task. The implications of these findings for the effects of marital strain on health as well as for the design of risk-reducing interventions, namely biofeedback are discussed.

A first-principles model of copper-boron interactions in Si: implications for the light-induced degradation of solar Si

The recent discovery that Cu contamination of Si combined with light exposure has a significant detrimental impact on carrier life-time has drawn much concern within the solar-Si community. The effect, known as the copper-related light-induced degradation (Cu-LID) of Si solar cells, has been connected to the release of Cu interstitials within the bulk (2016 Sol. Energy Mater. Sol. Cells 147 115-26). In this paper, we describe a comprehensive analysis of the formation/dissociation process of the CuB pair in Si by means of first-principles modelling, as well as the interaction of CuB defects with photo-excited minority carriers. We confirm that the long-range interaction between the [Formula: see text] cation and the [Formula: see text] anion has a Coulomb-like behaviour, in line with the trapping-limited diffusivity of Cu observed by transient ion drift measurements. On the other hand, the short-range interaction between the d-electrons of Cu and the excess of negative charge on [Formula: see text] produces a repulsive effect, thereby decreasing the binding energy of the pair when compared to the ideal point-charge Coulomb model. We also find that metastable CuB pairs produce acceptor states just below the conduction band minimum, which arise from the Cu level emptied by the B acceptor. Based on these results, we argue that photo-generated minority carriers trapped by the metastable pairs can switch off the Coulomb interaction that holds the pairs together, enhancing the release of Cu interstitials, and acting as a catalyst for Cu-LID.

Animal Slurry Acidification Affects Particle Size Distribution and Improves Separation Efficiency

Solid-liquid separation is performed to improve slurry management, and acidification of the slurry is used to reduce ammonia emissions. Acidification is known to affect slurry characteristics, and we hypothesized that it may affect mechanical separation. Our objective in this study was to assess the effects of slurry acidification on particle size distribution and separation efficiency. Two types of slurry, aged pig and fresh dairy, and two different acidification additives, sulfuric acid and aluminum sulfate (alum), were studied. We found that acidification with sulfuric acid promoted phosphorus (P) solubilization for both slurries, but no change was observed with alum. More ammonium was found in the acidified dairy slurry compared with raw dairy slurry, but no difference was found in aged pig slurry. Acidification before separation increased the proportion of the solid fraction in the slurries, and the effect was significantly higher with alum. When alum was used to acidify the slurries, the proportion of particles larger than 100 μm increased significantly, as did the P concentration in this particle size range. The efficiency of P separation increased markedly in both slurries when alum was used, with the removal to the solid fraction of the dairy slurry being almost complete (90%). Because the priority in mechanical separation is to increase the P content in the solid fraction, the use of alum before centrifugation may be the most suitable option for enhancing its nutrient content. We conclude that separation efficiency and particle size distribution are significantly affected by acidification, but the extent of the effects depends on slurry type and on the type of additive used for acidification.

Impact of slurry management strategies on potential leaching of nutrients and pathogens in a sandy soil amended with cattle slurry

For farmers, management of cattle slurry (CS) is now a priority, in order to improve the fertilizer value of the slurry and simultaneously minimize its environmental impact. Several slurry pre-treatments and soil application methods to minimize ammonia emissions are now available to farmers, but the impact of such management strategies on groundwater is still unclear. A laboratory experiment was performed over 24 days in controlled conditions, with undisturbed soil columns (sandy soil) in PVC pipes (30 cm high and 5.7 cm in diameter). The treatments considered (4 replicates) were: a control with no amendment (CTR), injection of whole CS (WSI), and surface application of: whole CS (WSS), acidified (pH 5.5) whole CS (AWSS), the liquid fraction obtained by centrifugation of CS (LFS), and acidified (pH 5.5) liquid fraction (ALFS). An amount of CS equivalent to 240 kg N ha(-1) was applied in all treatments. The first leaching event was performed 72 h after application of the treatments and then leaching events were performed weekly to give a total of four irrigation events (IEs). All the leachates obtained were analyzed for mineral and organic nitrogen, electrical conductivity (EC), pH, total carbon, and phosphorus. Total coliforms and Escherichia coli were also quantified in the leachates obtained in the first IE. The results show that both acidification and separation had significant effects on the composition of the leachates: higher NO3(-) concentrations were observed for the LFS and ALFS relative to all the other treatments, throughout the experiment, and lower NO3(-) concentrations were observed for acidified relative to non-acidified treatments at IE2. Acidification of both the LF and WS led to higher NH4(+) concentrations as well as an increase of EC for treatment ALFS relative to the control, in the first IE, and lower pH values in the AWSS. Furthermore, the E. coli and total coliform concentrations in AWSS, LFS, and ALFS were significantly higher than in WSI or WSS. In conclusion, none of the strategies generally used to minimize ammonia emissions impact positively on leaching potential relative to the traditional surface application of CS. Furthermore, some treatments, such as separation, might increase significantly the risk of leaching.

Strain-induced structure transformations on Si(111) and Ge(111) surfaces: a combined density-functional and scanning tunneling microscopy study

Si(111) and Ge(111) surface formation energies were calculated using density functional theory for various biaxial strain states ranging from -0.04 to 0.04, and for a wide set of experimentally observed surface reconstructions: 3 × 3, 5 × 5, 7 × 7 dimer-adatom-stacking fault reconstructions and c(2 × 8), 2 × 2, and √3×√3 adatoms based surfaces. The calculations are compared with scanning tunneling microscopy data obtained on stepped Si(111) surfaces and on Ge islands grown on a Si(111) substrate. It is shown that the surface structure transformations observed in these strained systems are accounted for by a phase diagram that relates the equilibrium surface structure to the applied strain. The calculated formation energy of the unstrained Si(111)-9 × 9 dimer-adatom-stacking fault surface is reported for the first time and it is higher than corresponding energies of Si(111)-5 × 5 and Si(111)-7 × 7 dimer-adatom-stacking fault surfaces as expected. We predict that the Si(111) surface should adopt a c(2 × 8) reconstruction when tensile strain is above 0.03.

Simple technologies for on-farm composting of cattle slurry solid fraction

Composting technologies and control systems have reached an advanced stage of development, but these are too complex and expensive for most agricultural practitioners for treating livestock slurries. The development of simple, but robust and cost-effective techniques for composting animal slurries is therefore required to realise the potential benefits of waste sanitation and soil improvement associated with composted livestock manures. Cattle slurry solid fraction (SF) was collected at the rates of 4m(3)h(-1) and 1m(3)h(-1) and composted in tall (1.7 m) and short (1.2m) static piles, to evaluate the physicochemical characteristics and nutrient dynamics of SF during composting without addition of bulking agent materials, and without turning or water addition. Highest maximum temperatures (62-64 °C) were measured in tall piles compared to short piles (52 °C). However, maximum rates of organic matter (OM) destruction were observed at mesophilic temperature ranges in short piles, compared to tall piles, whereas thermophilic temperatures in tall piles maximised sanitation and enhanced moisture reduction. Final OM losses were within the range of 520-660 g kg(-1) dry solids and the net loss of OM significantly (P<0.001) increased nutrient concentrations during the composting period. An advanced degree of stabilization of the SF was indicated by low final pile temperatures and C/N ratio, low concentrations of NH(4)(+) and increased concentrations of NO(3)(-) in SF composts. The results indicated that minimum intervention composting of SF in static piles over 168 days can produce agronomically effective organic soil amendments containing significant amounts of OM (772-856 g kg(-1)) and plant nutrients. The implications of a minimal intervention management approach to composting SF on compost pathogen reduction are discussed and possible measures to improve sanitation are suggested.

Apoptosis and insulin resistance in liver and peripheral tissues of morbidly obese patients is associated with different stages of non-alcoholic fatty liver disease

AIMS/HYPOTHESIS

Non-alcoholic fatty liver disease (NAFLD) is associated with insulin resistance and characterised by different degrees of hepatic lesion. Its pathogenesis and correlation with apoptosis and insulin resistance in insulin target tissues remains incompletely understood. We investigated how insulin signalling, caspase activation and apoptosis correlate with different NAFLD stages in liver, muscle and visceral adipose tissues.

METHODS

Liver, muscle and adipose tissue biopsies from 26 morbidly obese patients undergoing bariatric surgery were grouped according to the Kleiner-Brunt scoring system into simple steatosis, and less severe and more severe non-alcoholic steatohepatitis (NASH). Apoptosis was assessed by DNA fragmentation, and caspase-2 and -3 activation. Insulin signalling and c-Jun NH(2)-terminal kinase (JNK) proteins were evaluated by western blot.

RESULTS

Caspase-3 and -2 activation, and DNA fragmentation were markedly increased in the liver of patients with severe NASH vs in that of those with simple steatosis (p < 0.01). Muscle tissue, and to a lesser extent the liver, had decreased tyrosine phosphorylated insulin receptor and insulin receptor substrate in patients with severe NASH, compared with those with simple steatosis (p < 0.01 muscle; p < 0.05 liver). Concomitantly, Akt phosphorylation decreased in muscle, liver and visceral adipose tissues in patients with severe NASH (at least p < 0.05). Finally, JNK phosphorylation was significantly increased in muscle (p < 0.01) and liver (p < 0.05) from NASH patients, compared with tissue from those with simple steatosis.

CONCLUSIONS/INTERPRETATION

Our results demonstrate a link between apoptosis, insulin resistance and different NAFLD stages, where JNK and caspase-2 may play a key regulatory role.

Electronic structure of Zn, Cu and Ni impurities in germanium

We present a density functional modelling study of Zn, Cu and Ni impurities in hydrogen-terminated germanium clusters. Their electronic structure is investigated in detail, especially their Jahn-Teller instabilities and electrical levels. Interstitial and substitutional defects were considered and the latter were found to be the most stable defect form for nearly all Fermi level positions. Relative formation energies are estimated semi-empirically with the help of the measured formation energy of the single Ge vacancy. We find that while Zn is a double shallow acceptor, Cu and Ni are deep acceptors with levels close to the available experimental data. Donor levels were only found for interstitial Cu and Zn.

Methods to improve the composting process of the solid fraction of dairy cattle slurry

Cattle slurry solid fraction (SF) with different dry matter (DM) contents was collected from two dairy farms and composted in static and turned piles, with different sizes and cover types, to investigate the effects of pile conditions on the physical and chemical changes in SF during composting and to identify approaches to improve final compost quality. Thermophilic temperatures were attained soon after separation of SF, but the temperature of piles covered with polyethylene did not increase above 60 degrees C. The rate of organic matter (OM) mineralisation increased for turned piles in comparison to static piles, but the maximum amount of mineralisable OM (630-675gkg(-1)) was similar for all pile treatments. The C/N ratio declined from over 36 to a value of 14 towards the end of composting, indicating an advanced degree of OM stabilisation. Mature compost was obtained from raw SF feedstock as indicated by the low compost temperature, low C/N ratio, and low content of NH(4)(+) combined with increased concentrations of NO(3)(-). The efficiency of the composting process was improved and NH(3)-N losses were minimized by increasing DM content of the SF, reducing the frequency of pile turning and managing compost piles without an impermeable cover.

Self-interstitial in germanium

Low-temperature radiation damage in n- and p-type Ge is strikingly different, reflecting the charge-dependent properties of vacancies and self-interstitials. We find, using density functional theory, that in Ge the interstitial is bistable, preferring a split configuration when neutral and an open cage configuration when positively charged. The split configuration is inert while the cage configuration acts as a double donor. We evaluate the migration energies of the defects and show that the theory is able to explain the principal results of low-temperature electron-irradiation experiments.

Philadelphia-positive T-cell acute lymphoblastic leukemia with polymyositis, migratory polyarthritis and hypercalcemia following a chronic myeloid leukemia

Transformation of chronic myeloid leukemia (CML) often results in acute myeloblastic or, less frequently, in precursor B-cell acute lymphoblastic leukemia (ALL). T-cell blast crisis is rare. Hypercalcemia has also been described as a rare complication of CML, but this usually occurs as a terminal event. Here we report a case of a 35-year-old woman who developed a CD4(+)/CD8(+) T-cell ALL 2 years after the diagnosis of a typical Ph(+) CML. Polymyositis and polyarthritis preceded by 4 months, and symptomatic hypercalcemia occurred just before blastic transformation, probably representing paraneoplastic manifestations of the disease.

Thermal double donors and quantum dots

Combined local mode spectroscopy and ab initio modeling are used to demonstrate for the first time that oxygen atoms in thermal double donors (TDD) in Si are in close proximity. The observed vibrational modes in (16)O, (18)O, and mixed isotopic samples are consistent with a model involving [110] aligned oxygen chains made up of an insulating core lying between electrically active ends. The model also explains the minute spin density observed on oxygen in TDD(+) as well as the piezospectroscopic tensors of the donors. The analogy between the thermal donors and quantum dots is emphasized.

[Adrenergic beta inhibitors in heart insufficiency: which and when?]

After briefly reviewing the alterations of sympathetic nervous system in congestive heart failure and the possible ways of its pharmacological management, we review the present data regarding the use of blocking drugs in major trials (USCP, CIBIS and MERIT-HF). beta blocking drugs have a top and unquestionable role in the therapy of congestive heart failure; we conclude with a few practical rules about their use in this syndrome.

Pure red cell aplasia associated to clonal CD8+ T-cell large granular lymphocytosis: dependence on cyclosporin A therapy

This case report details a single patient with pure red cell aplasia (PRCA) associated with clonal CD3+, TCRalphabeta+, TCR-Vbeta8+, CD8+, CD57+ large granular lymphocytosis whose anaemia did not respond to conventional immunosuppressive therapy but did respond to cyclosporin A (CsA). The patient has become dependent on CsA for 7 years in order to control anaemia due to associated PRCA.

[Neutropenia]

The authors reviewed the subject of neutropenia in what concern its definition, pathophysiology, clinical features, diagnosis and principles of treatment. A new pathophysiological classification of neutropenia and an evaluation of neutropenic patients are proposed. The extent of laboratory evaluation depends greatly on the duration and severity of the neutropenia. The hematopoietic growth factors controlling the growth, development, differentiation and activation of the hematopoietic progenitor cells have revolutionized the treatment of neutropenia.

Cytogenetic findings in a patient presenting simultaneously with chronic lymphocytic leukemia and acute myeloid leukemia

A case of simultaneous presentation of B-chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML) is described. CLL was documented by bone marrow and peripheral blood lymphocytosis with a typical B-CLL immunophenotype. The diagnosis of AML was supported by the presence of bone marrow and circulating blast cells positive for myeloperoxidase and myeloid-associated markers. Although the immunophenotyping and morphocytochemical studies indicated two different cell populations (mature B-CLL lymphocytes and myeloblasts), chromosome aberrations commonly associated with CLL and AML were found simultaneously in the same metaphases obtained from unstimulated 24-hour cultures of peripheral blood cells.

Immunophenotypic characteristics of acute leukaemia after myelodysplastic syndromes

PURPOSE

To analyse the immunophenotype of acute leukaemia (AL) after myelodysplastic syndromes (MDS) (MDS-AL) and to compare the immunophenotypic profile of acute myeloblastic leukaemia (AML) secondary to MDS (MDS-AML) with that of "de novo"-AML.

PATIENTS AND METHODS

Twenty patients with MDS-AL and 29 patients with "de novo"-AML were studied. Morphocytochemical and flow cytometric studies were done in each case.

RESULTS

All the MDS-AL studied displayed a myeloid phenotype (MDS-AML). The main difference between MDS-AML and "de novo"-AML was a significantly higher frequency of CD34 expression in the first group. Differences concerning the expression of other non-lineage related or myeloid-associated markers were not statistically significant, although the percentage of cases CD15(+) was lower in MDS-AML. The overall frequency of expression of lymphoid-associated markers was similar in both groups, T-cell markers being more frequently detected.

CONCLUSIONS

Our findings support the usefulness of immunophenotyping studies to characterize MDS-AL and suggest some immunophenotyping differences between MDS-AML and "de novo"-AML which might have biological and prognostic significance.

Chronic prolymphocytoid leukaemia with an unusual immature immunophenotype

A case of a 58 year old woman with a chronic lymphoproliferative disorder of unusual clinical presentation, disease course, and immunophenotype is presented. At diagnosis she had severe anaemia, moderate lymphocytosis with some cells having prolymphocytoid features and a normal platelet count. A clinical examination yielded negative results. Only anaemia related symptoms were found and the patient became blood transfusion dependent. Both the lymphocytosis and the proportion of prolymphocytoid cells rose insidiously and thrombocytopenia developed later during the course of the disease. Three years later, the patient had a white cell count of 269 x 10(9)/l almost exclusively of prolymphocytoid cells and the bone marrow was diffusely infiltrated. She was refractory to chemotherapy and the anaemia did not improve after treatment with cyclosporine. Lymphoid cells were positive for cytoplasmatic CD3, HLA-Dr, CD34, CD38, CD7, CD56, CD13, CD33 and CD65. Membrane alpha beta and gamma delta T cell receptors (TCRs) were not expressed and the beta chain TCR gene was in germline configuration. Other membrane T, B, natural killer, and myelomonocytic markers were negative. Karyotype analysis was tried several times but metaphases were not obtained, even after stimulation with T cell mitogens.

[Cytogenetic studies in hematological diseases. Analysis of 185 cases]

PURPOSE

To analyse the chromosomal abnormalities found at diagnosis in patients with malignant blood diseases.

PATIENTS AND METHODS

Between june 1988 and january 1992, cytogenetic studies were performed at the Cytogenetics Laboratory of the Abel Salazar Institute for Biomedical Sciences on 185 patients with malignant blood diseases. Bone-marrow and/or peripheral blood cells were used for such studies, two simultaneous cultures being prepared at 24 and 48 hr, plus another one, stimulated with phytohemagglutinin, at 72 hr. Trypsin G-banding techniques were used for chromosome identification. Chromosomes were classified in accordance with the international system, and a clone was judged abnormal whenever two or more metaphases showed identical structural abnormalities or extra chromosome(s) and three or more metaphases lacked the same chromosome(s).

RESULTS

Evaluable mitoses were found in 152 of the 185 cytogenetic studies performed (82.2%), pertaining to chronic myelogenous leukaemia (39/42), acute nonlymphoblastic leukaemia (40/43), myelodysplastic syndromes (10/17), acute lymphoblastic leukaemia (30/36), and chronic lymphoproliferative disorders (10/14). Chromosomal alterations, previously described in each diagnostic variety, were found in 69% of the cases with abnormal karyotype. The remaining patients (31%) had chromosomal abnormalities not reported consistently.

CONCLUSIONS

The karyotype should be studied regularly in haematologic disorders since, although lacking precise prognostic implications, it may help gain information with regard to the genetic alterations in different blood diseases.

[Variability of heart rate: a perspective]

The present work is an attempt to provide a general overview on the current methods and applications of heart rate variability (HRV), starting from the underlying mechanisms of cardiac rhythmic automaticity and the influence on heart rate of biological modulators, namely autonomous nervous system. Different evaluation methods for HRV are compared in what concerns the duration of the records under analysis and the mathematical approach (spectral/non-spectral). Finally, clinical applications of HRV are mentioned, some of them the Department is particularly interested in, namely coronary heart disease, heart failure and diabetic neuropathy. The authors conclude, minding some aspects susceptible of discussion in the future of this technique.

Choledochoenterostomy with an anti-reflux mechanism

A new technique of choledochoenterostomy was devised to solve some of the problems of enterobiliary anastomosis with a normal calibre. The distal extremity of the common bile duct is completely surrounded by the bowel mucosa to a length of 3 cm after seromyectomy of a bowel wall rectangle of 4 x 1 cm. Experimental studies in rats and dogs demonstrated that this procedure prevents the risks of anastomotic disruption and functions like a mechanical unidirectional valve, which has great efficacy in stopping enterobiliary reflux. Studies in ten patients with obstructive jaundice with an extrahepatic biliary dilation less than 1.2 cm diameter submitted to this procedure confirmed the experimental results. All patients were asymptomatic, without jaundice and with normalization of the liver enzymes after 2 months. The permeability of the valvular anastomosis studied by cholangiography, the HIDA 99mTc test and manometry was quite similar to other classical biliary-enteric anastomosis. In contrast, anti-reflux efficacy was only demonstrated in patients with a valvular anastomosis.

[Preservation of the liver using a new solution of phosphate-buffered saccharose]

The efficacy of the new phosphate-buffered sucrose solution (PBS), was compared with the conventional Euro-Collins (EC) and the lactated Ringer solution (LR), in its capacity to preserve the canine liver in cold storage. Three groups of 6 canine livers, each group in one of those solutions, were put in cold storage for 24 h at 4 degrees centigrade. At the end of this period the effect of warm hepatic reperfusion was studied in relationship with the following parameters: weight of the liver, bile excretion, hepatic biopsy, Na, K, Ca, P and some tests used to evaluate the hepatic function. The results obtained confirm, that PBS has an important impermeant effect over the hepatocyte, simulating that described recently by Lam et al to the kidney. Contrary to the EC and LR, the PBS inhibits hypothermic cell swelling, is more effective in the preservation of the liver histology, and has an opposed effect to the weight gain tendency induced by cold storage. During the period of warm reperfusion, high volumes of bile excretion and lesser levels of K depletion were observed in the PBS model. PBS is easy to prepare, and it is not expensive. For these reasons PBS could be an advantageous substitute of the EC in liver preservation.