Cellulose-Callose Hydrogels: Computational Exploration of Their Nanostructure and Mechanical Properties

Polysaccharides play a crucial role in virtually all living systems. They also represent the biocompatible and fully sustainable component of a variety of nanoparticles, which are of increasing interest in biomedicine, food processing, cosmetics, and structural reinforcement of polymeric materials. The computational modeling of complex polysaccharide phases will assist in understanding the properties and behavior of all these systems. In this paper, structural, bonding, and mechanical properties of 10 wt % cellulose-callose hydrogels (β-glucans coexisting in plant cell walls) were investigated by atomistic simulations. Systems of this kind have recently been introduced in experiments revealing unexpected interactions between the polysaccharides. Starting from initial configurations inspired by X-ray diffraction data, atomistic models made of ∼1.6 × 106 atoms provide a qualitatively consistent view of these hydrogels, displaying stability, homogeneity, connectivity, and elastic properties beyond those of a liquid suspension. The simulation shows that the relatively homogeneous distribution of saccharide nanofibers and chains in water is not due to the solubility of cellulose and callose, but to the formation of a number of cross-links among the various sample components. The broad distribution of strength and elasticity among the links implies a degree of anharmonicity and irreversible deformation already evident at low external load. Besides the qualitative agreement with experimental observations, the simulation results display also quantitative disagreements in the estimation of elastic coefficients, such as the Young's modulus, that require further investigation. Complementary simulations of dense cellulose-callose mixtures (no hydrogels) highlight the role of callose in smoothing the contact surface of different nanofibers forming larger bundles. Cellulose-callose structures in these systems displayed an enhanced water uptake and delayed dye release when compared to cellulose alone, highlighting potential new applications as drug delivery scaffolds. The simulation trajectories provide a tuning and testing ground for the development of coarse-grained models that are required for the large scale investigation of mechanical properties of cellulose and callose mixtures in a watery environment.

Suppressing the rhamnogalacturonan lyase gene FaRGLyase1 preserves RGI pectin degradation and enhances strawberry fruit firmness

Plant rhamnogalacturonan lyases (RGLyases) cleave the backbone of rhamnogalacturonan I (RGI), the "hairy" pectin and polymer of the disaccharide rhamnose (Rha)-galacturonic acid (GalA) with arabinan, galactan or arabinogalactan side chains. It has been suggested that RGLyases could participate in remodeling cell walls during fruit softening, but clear evidence has not been reported. To investigate the role of RGLyases in strawberry softening, a genome-wide analysis of RGLyase genes in the genus Fragaria was performed. Seventeen genes encoding RGLyases with functional domains were identified in Fragaria × ananassa. FaRGLyase1 was the most expressed in the ripe receptacle of cv. Chandler. Transgenic strawberry plants expressing an RNAi sequence of FaRGLyase1 were obtained. Three transgenic lines yielded ripe fruits firmer than controls without other fruit quality parameters being significantly affected. The highest increase in firmness achieved was close to 32%. Cell walls were isolated from ripe fruits of two selected lines. The amount of water-soluble and chelated pectins was higher in transgenic lines than in the control. A carbohydrate microarray study showed a higher abundance of RGI epitopes in pectin fractions and in the cellulose-enriched fraction obtained from transgenic lines. Sixty-seven genes were differentially expressed in transgenic ripe fruits when compared with controls. These genes were involved in various physiological processes, including cell wall remodeling, ion homeostasis, lipid metabolism, protein degradation, stress response, and defense. The transcriptomic changes observed in FaRGLyase1 plants suggest that senescence was delayed in transgenic fruits.

CRISPR/Cas9 editing of the polygalacturonase FaPG1 gene improves strawberry fruit firmness

Firmness is one of the most important fruit quality traits in strawberries. The postharvest shelf life of this soft fruit is highly limited by the loss of firmness, where cell wall disassembly plays an important role. Previous studies demonstrated that the polygalacturonase FaPG1 has a key role in remodelling pectins during strawberry softening. In this study, FaPG1 knockout strawberry plants have been generated using the CRISPR/Cas9 system delivered via Agrobacterium tumefaciens. Ten independent lines, cv. "Chandler", were obtained, and all of them were successfully edited as determined by PCR amplification and T7 endonuclease assay. The targeted mutagenesis insertion and deletion rates were analyzed using targeted deep sequencing. The percentage of edited sequences varied from 47% up to almost 100%, being higher than 95% for seven of the selected lines. Phenotypic analyses showed that 7 out of the eight lines analyzed produced fruits significantly firmer than the control, ranging from 33 to 70% increase in firmness. There was a positive relationship between the degree of FaPG1 editing and the rise in fruit firmness. Minor changes were observed in other fruit quality traits, such as colour, soluble solids, titratable acidity or anthocyanin content. Edited fruits showed a reduced softening rate during postharvest, displayed a reduced transpirational water loss, and were less damaged by Botrytis cinerea inoculation. The analysis of four potential off-target sites revealed no mutation events. In conclusion, editing the FaPG1 gene using the CRISPR/Cas9 system is an efficient method for improving strawberry fruit firmness and shelf life.

Plasmodesmata and their role in the regulation of phloem unloading during fruit development

Fruit consumption is fundamental to a balanced diet. The contemporary challenge of maintaining a steady food supply to meet the demands of a growing population is driving the development of strategies to improve the production and nutritional quality of fruit. Plasmodesmata, the structures that mediate symplasmic transport between plant cells, play an important role in phloem unloading and distribution of sugars and signalling molecules into developing organs. Targeted modifications to the structures and functioning of plasmodesmata have the potential to improve fruit development; however, knowledge on the mechanisms underpinning plasmodesmata regulation in this context is scarce. In this review, we have compiled current knowledge on plasmodesmata and their structural characterisation during the development of fruit organs. We discuss key questions on phloem unloading, including the pathway shift from symplasmic to apoplastic that takes place during the onset of ripening as potential targets for improving fruit quality.

School stress and health complaints: Testing the Adolescent Stress Questionnaire in Spain and Sweden

Background

According to the Health Behaviour in School-aged Children (HBSC) study, over a third of adolescents feel pressured by schoolwork in European countries, with increases associated to age and in girls. School pressure has been linked with increased health complaints, which illustrates the importance of schools from a public health perspective. To get a better understanding of school stress in adolescence, there is a need to test measures that reflect a broader array of potential school-related stressors. The aims of this cross-national study were: (1) to analyze the functioning of a specific measure to assess school stress in adolescence and (2) to examine the links between school stress and health complaints.

Methods

The sample consisted of students aged 13 and 15 years: 1,249 students (54.6% girls) who had participated in project EASE in Spain, and 576 students (50.6% girls) in Sweden. The measure tested was the Adolescent Stress Questionnaire (ASQ-S), specifically the 9 items on school stress from the subscales school performance, future uncertainty, and school-leisure conflict. For the assessment of health complaints, the HBSC health complaints checklist was used.

Results

CFA supported a three-correlated factor structure and a high reliability of the three subscales of the ASQ-S in both countries. In regression analyses, the association between school stress and health complaints was significant when controlling age and sex, with the increase in the level of explained variability due to several stress dimensions being 18.8% in Spain and 25.2% in Sweden.

Conclusions

Different facets of school life can contribute to stress during adolescence, with more public health attention needed when it comes to school stress and its links with increased health complaints.

Key messages

The instrument used for school stress may be useful in cross-national studies in adolescent samples. More public health attention should be paid to school stress and its links with increased health complaints in adolescence.

Back to school during the COVID-19 pandemic: Does students’ stress differ by socioeconomic status?

Background

With COVID-19 disrupting school life, there is a need to examine whether COVID-related changes in our schools may be creating or exacerbating inequalities among students. The aim of this poster is to examine potential differences associated to socioeconomic status (SES) both in different facets of school stress, and in the overall impact of COVID and specific school COVID-related measures.

Methods

Sample consisted of 2,523 secondary school students (52.3% girls, M age = 13.78) from Spain who had participated in Project EASE from November 2020 to mid-January 2021, i.e. shortly after schools reopened for the new academic year. Using ANOVA and Chi-square analyses, differences associated to SES were examined in: (1) school stress, for which we used 3 subscales of the ASQ-S (school performance, future uncertainty, and school-leisure conflict), and (2) the perceived impact of COVID and specific school COVID-related measures (e.g. hygiene measures, social distancing, increased ICTs use) on stress levels.

Results

We found no significant differences associated to SES in stress of school performance or stress of school-leisure conflict, but low SES was associated with higher stress due to future uncertainty. Regardless of SES, the majority of students reported that their levels of school stress had increased due to COVID-19. As for specific measures, the percentage of students that reported an increase in their level of stress due to the more frequent use of ICTs was higher among low-SES students, who also reported lower levels of stress associated to reduced contact with classmates due to COVID.

Conclusions

Although most students reported an increase in school stress due to COVID-19, low-SES students experienced significantly higher stress due to future uncertainty. Potential differences in the role of specific school COVID-related measures would also deserve further examination.

Key messages

Low-SES students experienced higher levels of stress due to future uncertainty.

The majority of students, regardless of SES, reported increases in their stress levels due to COVID-19.

Elucidating the role of polygalacturonase genes in strawberry fruit softening

To disentangle the role of polygalacturonase (PG) genes in strawberry softening, the two PG genes most expressed in ripe receptacles, FaPG1 and FaPG2, were down-regulated. Transgenic ripe fruits were firmer than those of the wild type when PG genes were silenced individually. Simultaneous silencing of both PG genes by transgene stacking did not result in an additional increase in firmness. Cell walls from ripe fruits were characterized by a carbohydrate microarray. Higher signals of homogalacturonan and rhamnogalacturonan I pectin epitopes in polysaccharide fractions tightly bound to the cell wall were observed in the transgenic genotypes, suggesting a lower pectin solubilization. At the transcriptomic level, the suppression of FaPG1 or FaPG2 alone induced few transcriptomic changes in the ripe receptacle, but the amount of differentially expressed genes increased notably when both genes were silenced. Many genes encoding cell wall-modifying enzymes were down-regulated. The expression of a putative high affinity potassium transporter was induced in all transgenic genotypes, indicating that cell wall weakening and loss of cell turgor could be linked. These results suggest that, besides the disassembly of pectins tightly linked to the cell wall, PGs could play other roles in strawberry softening, such as the release of oligogalacturonides exerting a positive feedback in softening.

Interactions between callose and cellulose revealed through the analysis of biopolymer mixtures

The properties of (1,3)-β-glucans (i.e., callose) remain largely unknown despite their importance in plant development and defence. Here we use mixtures of (1,3)-β-glucan and cellulose, in ionic liquid solution and hydrogels, as proxies to understand the physico-mechanical properties of callose. We show that after callose addition the stiffness of cellulose hydrogels is reduced at a greater extent than predicted from the ideal mixing rule (i.e., the weighted average of the individual components’ properties). In contrast, yield behaviour after the elastic limit is more ductile in cellulose-callose hydrogels compared with sudden failure in 100% cellulose hydrogels. The viscoelastic behaviour and the diffusion of the ions in mixed ionic liquid solutions strongly indicate interactions between the polymers. Fourier-transform infrared analysis suggests that these interactions impact cellulose organisation in hydrogels and cell walls. We conclude that polymer interactions alter the properties of callose-cellulose mixtures beyond what it is expected by ideal mixing.

Despite their importance in plant development and defence the properties of (1,3)-β-glucan remain largely unknown. Here, the authors find that addition of (1,3)-β-glucans increases the flexibility of cellulose and its resilience to high strain, an effect originating in molecular level interactions.

Structural changes in cell wall pectins during strawberry fruit development

Strawberry (Fragaria × anannasa Duch.) is one of the most important soft fruit. Rapid loss of firmness occurs during the ripening process, resulting in a short shelf life and high economic losses. To get insight into the role of pectin matrix in the softening process, cell walls from strawberry fruit at two developmental stages, unripe-green and ripe-red, were extracted and sequentially fractionated with different solvents to obtain fractions enriched in a specific component. The yield of cell wall material as well as the per fresh weight contents of the different fractions decreased in ripe fruit. The largest reduction was observed in the pectic fractions extracted with a chelating agent (trans-1,2- diaminocyclohexane-N,N,N'N'-tetraacetic acid, CDTA fraction) and those covalently bound to the wall (extracted with Na₂CO₃). Uronic acid content of these two fractions also decreased significantly during ripening, but the amount of soluble pectins extracted with phenol:acetic acid:water (PAW) and water increased in ripe fruit. Fourier transform infrared spectroscopy of the different fractions showed that the degree of esterification decreased in CDTA pectins but increased in soluble fractions at ripen stage. The chromatographic analysis of pectin fractions by gel filtration revealed that CDTA, water and, mainly PAW polyuronides were depolymerised in ripe fruit. By contrast, the size of Na₂CO₃ pectins was not modified. The nanostructural characteristics of CDTA and Na₂CO₃ pectins were analysed by atomic force microscopy (AFM). Isolated pectic chains present in the CDTA fractions were significantly longer and more branched in samples from green fruit than those from red fruit. No differences in contour length were observed in Na₂CO₃ strands between samples of both stages. However, the percentage of branched chains decreased from 19.7% in unripe samples to 3.4% in ripe fruit. The number of pectin aggregates was higher in green fruit samples of both fractions. These results show that the nanostructural complexity of pectins present in CDTA and Na₂CO₃ fractions diminishes during fruit development, and this correlates with the solubilisation of pectins and the softening of the fruit.

Dirigent proteins in plants: modulating cell wall metabolism during abiotic and biotic stress exposure

Dirigent (DIR) proteins were found to mediate regio- and stereoselectivity of bimolecular phenoxy radical coupling during lignan biosynthesis. Here we summarize the current knowledge of the importance of DIR proteins in lignan and lignin biosynthesis and highlight their possible importance in plant development. We focus on the still rather enigmatic Arabidopsis DIR gene family, discussing the few members with known functional importance. We comment on recent discoveries describing the detailed structure of two DIR proteins with implications in the mechanism of DIR-mediated catalysis. Further, we summarize the ample evidence for stress-induced dirigent gene expression, suggesting the role of DIRs in adaptive responses. In the second part of our work, we present a preliminary bioinformatics-based characterization of the AtDIR family. The phylogenetic analysis of AtDIRs complemented by comparison with DIR proteins of mostly known function from other species allowed us to suggest possible roles for several members of this family and identify interesting AtDIR targets for further study. Finally, based on the available metadata and our in silico analysis of AtDIR promoters, we hypothesize about the existence of specific transcriptional controls for individual AtDIR genes and implicate them in various stress responses, hormonal regulations, and developmental processes.

Antisense down-regulation of the strawberry β-galactosidase gene FaβGal4 increases cell wall galactose levels and reduces fruit softening

Strawberry softening is characterized by an increase in the solubilization and depolymerization of pectins from cell walls. Galactose release from pectin side chains by β-galactosidase enzymes has been proposed as one reason for the increase in soluble pectins. A putative β-galactosidase gene, FaβGal4, has been identified using a custom-made oligonucleotide-based strawberry microarray platform. FaβGal4 was expressed mainly in the receptacle during fruit ripening, and was positively regulated by abscisic acid and negatively regulated by auxins. To ascertain the role of FaβGal4 in strawberry softening, transgenic plants containing an antisense sequence of this gene under the control of the CaMV35S promoter were generated. Phenotypic analyses were carried out in transgenic plants during three consecutive growing seasons, using non-transformed plants as control. Two out of nine independent transgenic lines yielded fruits that were 30% firmer than control at the ripe stage. FaβGal4 mRNA levels were reduced by 70% in ripe fruits from these selected transgenic lines, but they also showed significant silencing of FaβGal1, although the genes did not share significant similarity. These two transgenic lines also showed an increase in pectin covalently bound to the cell wall, extracted using Na2CO3. The amount of galactose in cell walls from transgenic fruits was 30% higher than in control; notably, the galactose increase was larger in the 1 M KOH fraction, which is enriched in hemicellulose. These results suggest that FaβGal4 participates in the solubilization of covalently bound pectins during ripening, reducing strawberry fruit firmness.

Fruit softening and pectin disassembly: an overview of nanostructural pectin modifications assessed by atomic force microscopy

BACKGROUND

One of the main factors that reduce fruit quality and lead to economically important losses is oversoftening. Textural changes during fruit ripening are mainly due to the dissolution of the middle lamella, the reduction of cell-to-cell adhesion and the weakening of parenchyma cell walls as a result of the action of cell wall modifying enzymes. Pectins, major components of fruit cell walls, are extensively modified during ripening. These changes include solubilization, depolymerization and the loss of neutral side chains. Recent evidence in strawberry and apple, fruits with a soft or crisp texture at ripening, suggests that pectin disassembly is a key factor in textural changes. In both these fruits, softening was reduced as result of antisense downregulation of polygalacturonase genes. Changes in pectic polymer size, composition and structure have traditionally been studied by conventional techniques, most of them relying on bulk analysis of a population of polysaccharides, and studies focusing on modifications at the nanostructural level are scarce. Atomic force microscopy (AFM) allows the study of individual polymers at high magnification and with minimal sample preparation; however, AFM has rarely been employed to analyse pectin disassembly during fruit ripening.

SCOPE

In this review, the main features of the pectin disassembly process during fruit ripening are first discussed, and then the nanostructural characterization of fruit pectins by AFM and its relationship with texture and postharvest fruit shelf life is reviewed. In general, fruit pectins are visualized under AFM as linear chains, a few of which show long branches, and aggregates. Number- and weight-average values obtained from these images are in good agreement with chromatographic analyses. Most AFM studies indicate reductions in the length of individual pectin chains and the frequency of aggregates as the fruits ripen. Pectins extracted with sodium carbonate, supposedly located within the primary cell wall, are the most affected.

Insights into the effects of polygalacturonase FaPG1 gene silencing on pectin matrix disassembly, enhanced tissue integrity, and firmness in ripe strawberry fruits

Antisense-mediated down-regulation of the fruit-specific polygalacturonase (PG) gene FaPG1 in strawberries (Fragaria×ananassa Duch.) has been previously demonstrated to reduce fruit softening and to extend post-harvest shelf life, despite the low PG activity detected in this fruit. The improved fruit traits were suggested to be attributable to a reduced cell wall disassembly due to FaPG1 silencing. This research provides empirical evidence that supports this assumption at the biochemical, cellular, and tissue levels. Cell wall modifications of two independent transgenic antisense lines that demonstrated a >90% reduction in FaPG1 transcript levels were analysed. Sequential extraction of cell wall fractions from control and ripe fruits exhibited a 42% decrease in pectin solubilization in transgenic fruits. A detailed chromatographic analysis of the gel filtration pectin profiles of the different cell wall fractions revealed a diminished depolymerization of the more tightly bound pectins in transgenic fruits, which were solubilized with both a chelating agent and sodium carbonate. The cell wall extracts from antisense FaPG1 fruits also displayed less severe in vitro swelling. A histological analysis revealed more extended cell-cell adhesion areas and an enhanced tissue integrity in transgenic ripe fruits. An immunohistological analysis of fruit sections using the JIM5 antibody against low methyl-esterified pectins demonstrated a higher labelling in transgenic fruit sections, whereas minor differences were observed with JIM7, an antibody that recognizes highly methyl-esterified pectins. These results support that the increased firmness of transgenic antisense FaPG1 strawberry fruits is predominantly due to a decrease in pectin solubilization and depolymerization that correlates with more tightly attached cell wall-bound pectins. This limited disassembly in the transgenic lines indicates that these pectin fractions could play a key role in tissue integrity maintenance that results in firmer ripe fruit.

[The 2013 Seville Consensus Document on alternatives to allogenic blood transfusion. An update on the Seville Document]

Since allogeneic blood transfusion (ABT) is not harmless, multiple alternatives to ABT (AABT) have emerged, though there is great variability in their indications and appropriate use. This variability results from the interaction of a number of factors, including the specialty of the physician, knowledge and preferences, the degree of anemia, transfusion policy, and AABT availability. Since AABTs are not harmless and may not meet cost-effectiveness criteria, such variability is unacceptable. The Spanish Societies of Anesthesiology (SEDAR), Hematology and Hemotherapy (SEHH), Hospital Pharmacy (SEFH), Critical Care Medicine (SEMICYUC), Thrombosis and Hemostasis (SETH) and Blood Transfusion (SETS) have developed a Consensus Document for the proper use of AABTs. A panel of experts convened by these 6 Societies have conducted a systematic review of the medical literature and have developed the 2013 Seville Consensus Document on Alternatives to Allogeneic Blood Transfusion, which only considers those AABT aimed at decreasing the transfusion of packed red cells. AABTs are defined as any pharmacological or non-pharmacological measure aimed at decreasing the transfusion of red blood cell concentrates, while preserving patient safety. For each AABT, the main question formulated, positively or negatively, is: « Does this particular AABT reduce the transfusion rate or not?» All the recommendations on the use of AABTs were formulated according to the Grades of Recommendation Assessment, Development and Evaluation (GRADE) methodology.

[The 2013 Seville Consensus Document on alternatives to allogenic blood transfusion. An update on the Seville Document]

Since allogeneic blood transfusion (ABT) is not harmless, multiple alternatives to ABT (AABT) have emerged, though there is great variability in their indications and appropriate use. This variability results from the interaction of a number of factors, including the specialty of the physician, knowledge and preferences, the degree of anemia, transfusion policy, and AABT availability. Since AABTs are not harmless and may not meet cost-effectiveness criteria, such variability is unacceptable. The Spanish Societies of Anesthesiology (SEDAR), Hematology and Hemotherapy (SEHH), Hospital Pharmacy (SEFH), Critical Care Medicine (SEMICYUC), Thrombosis and Hemostasis (SETH) and Blood Transfusion (SETS) have developed a Consensus Document for the proper use of AABTs. A panel of experts convened by these 6 Societies have conducted a systematic review of the medical literature and have developed the 2013 Seville Consensus Document on Alternatives to Allogeneic Blood Transfusion, which only considers those AABT aimed at decreasing the transfusion of packed red cells. AABTs are defined as any pharmacological or non-pharmacological measure aimed at decreasing the transfusion of red blood cell concentrates, while preserving patient safety. For each AABT, the main question formulated, positively or negatively, is: "Does this particular AABT reduce the transfusion rate or not?" All the recommendations on the use of AABTs were formulated according to the Grades of Recommendation Assessment, Development and Evaluation (GRADE) methodology.

The attraction of topographical technique

The author argues that although the topographical model is useful for understanding certain psychological phenomena, its technical applications pose certain problems. The model's inherent tendency to bypass the analysand's ego capacities and mix his or her associations with the analyst's own make it less than adequate. There has never been a rapid evolution of psychoanalytic technique, and topographical and structural concepts have been applied in an unclear way. It is inaccurate to think that making the unconscious conscious is mostly characteristic of topographical technique, for the structural approach is a more comprehensive method for attaining this goal. The difficulties in transcending topographical technique seem to be related to certain historical inertias and irrational factors that make it especially attractive. Among these are the appeal of its simplicity, the gratification of epistemophilic and narcissistic tendencies, and the propitious ground for the analyst's projections that is provided by interpretations. The role of suggestion in topographical technique, its therapeutic effectiveness and its syntonicity are discussed and two brief clinical vignettes are presented. The author concludes that it is mainly because of its magnetic regressive features that this technique has not been superseded by the structural approach.

[Neurobiology and psychoanalysis]

Psychiatry obtains benefits from integrating the findings of neurobiology with the knowledge of depth psychology. In this paper, relevant recent research in neuroscience is reviewed from the perspective of psychoanalytic theory. Psychoanalytic experience and hypotheses have stimulated numerous experiments and research projects in neurobiology. Neurobiological findings have brought forward the neurophysiological substrate of clinical phenomena described by psychoanalysts, assisting in the specification of some theoretical notions, and making us modify others that were considered as already established. From a neurobiological viewpoint, some studies considered pertinent are commented upon on associations, apperception and unconscious perception, memory, and hemispheric specialisation and its psychological corollary.

Aeromonas hydrophila associated with a severe outbreak of infection in farmed rabbits

An outbreak of infection with a high rate of mortality has been detected in an industrial rabbitry in Spain. Aeromonas hydrophila was isolated in pure culture from liver, lung, heart and spleen of ill and moribund animals. All the isolates belonged to O:11 serogroup, autogglutinated after boiling, were resistant to the bactericidal action of the fresh rabbit serum and did not agglutinate in acriflavine. They were producers of hemolysins and proteases but were not enterotoxigenic.

Acting in revisited

Acting in' is a term that has not met with much success in the psychoanalytic literature. The literature has focused mainly on quite dramatic forms of acting during sessions rather than on subtler and more common forms of intraclinical acting. Zeligs (1957) gave the term 'acting in' a surprisingly restrictive denotation. A redefinition is suggested, characterising this concept with three features: it is a non-verbal action involving the somatic musculature; it has conscious or unconscious meaning conducive to the exploration of dynamics; and it takes place in the session. Inclusive and exclusive criteria are reviewed for the clarification of this important concept. 'Acting in' is not considered synonymous with 'acting out in the transference'. Unlike 'acting out', 'acting in' can be predominantly of an extratransferential or a genetic nature. Enactments usually include episodes of acting in. What is considered most typical of acting in is the fact of its direct observability and consequent demonstrability to the patient. It is contended that instances of acting in represent a nodal point where the clinical surface becomes especially workable. Clinical vignettes are provided. It is suggested that in order to include acting in in the mainstream of resistance analysis, interpretive assistance should be given to analysands to translate these episodes consistently into verbal understanding.

[Hospital use of fresh frozen plasma]

PURPOSE

The aim of this work is double. On the one hand, to assess if the measures to strictly control the clinical indications of fresh-frozen plasma (FFP) transfusion may lead to a decrease of its use, and on the other to assess the importance of FFP with regard to other blood components, along with disclosing the number and characteristics of the more patients and those who receive only FFP.

MATERIAL AND METHODS

Starting from data of the blood bank and the hospital records, an analysis of the use of FFP in the General Hospital was carried out, and it was correlated with the use of other blood components, mostly red cells (RC), and the hospital indices expressed as DRG. An analysis was also performed of the use of FFP in 1996 with regard to the number of transfused patients, mean consumed units in general and according to patient-groups, association with RC use and identification of high-use patients (defined as requiring over 3 FFP units).

RESULTS

A decrease in the use of FFP between 1992 and 1996 was appreciated, from 1,385 to 760 units. This decrease, when correlated with the use of RC, was from 17.8 to 9.2 FFP units/ 100 RC units during this period. The FFP units/100 RC units varied from 6 to 2 in three years; this index has been stable since then. With regard to the use in 1996, 162 patients received FFP, which represents 4% of all the transfusions in the hospital. Of these, 15 patients received only plasma (9% of the patients receiving FFP and 0.3% of all transfusions). Other blood components, mainly RC, were associated to FFP in 96% of the cases. The patients consuming more FFP units were those of heart surgery and intensive care units, with significant differences with respect to others.

CONCLUSIONS

This study shows a steady decrease in the use of FFP, which is stable in the last years. The patients receiving only FFP represented a low number with respect to all the patients transfused. The follow-up of these patients might provide valuable data about the benefit of adding additional security processes to standard FFP.

Negative acting in

Little has been written on the analysand's failure to act in the session when some form of motoric reaction or behavior seems appropriate and expectable. This phenomenon is conceptualized as negative acting in. Several clinical vignettes are provided. The importance of analytic interventions at these moments of behavioral omission, the possible countertransferential interferences, and the frequent use by the patient of rationalizations are commented on. The point is made that even though the exploration of these nodal points does not always lead to the discernment of psychodynamics, it usually contributes to the fostering of ego-observing capacities. Detection of episodes of negative acting in may pose special difficulties for the analyst, since it requires that attention be focused on events that do not take place, but their exploration is considered important for an analysis of the patient's psychic life.

Common ground, uncommon methods

The author, an American-trained psychoanalyst, currently a member of a theoretically heterogeneous European psychoanalytic society, reflects on his experiences with the different types of analysis practised in continental Europe and in the United States. Sharing some 'common ground' assumptions does not mean that analysts worldwide use comparable clinical methodology. Practitioners from disparate schools differ not only in their metatheoretical frameworks, but also in their theories of technique. Differences in clinical methods affect the scientific quality of clinical researches and, probably, influence therapeutic outcome. The lack of commonality in psychoanalytic methods often seems related to the disparate uses of logical fallacies in clinical reasoning; this, in turn, may be a consequence of socio-historical determinants. Several discussions of one clinical presentation are supplied as an illustration. It is suggested that efforts be made to further examine the relative validity of disparate inference-making models, and the practical results of applying different clinical methods.

[Evolutive epidemiologic profile of myelodysplastic syndromes (1959-1993). Comparative study with acute myeloid leukemia and aplastic pancytopenias]

PURPOSE

To compare the maximum epidemiologic data attained from myelodysplastic syndromes (MDS) with those of two main panmyelopathies, namely acute myeloblastic leukaemia (AML) and aplastic pancytopenia (AP).

PATIENTS AND METHODS

A retrospective analysis was carried out on 21,135 patients included in the Bone Marrow Study Registry of the Jiménez Díaz Foundation along 35 years (1959-1993). The data were grouped into seven five-year periods. Of these, in the first three the study was performed on bone-marrow aspirates; after 1976 the histopathological study of bone-marrow biopsies was introduced, and since 1979 the karyotype has been regularly examined. The MDS were classified in accordance with the FAB system. With these premises borne in mind, the following aspects were considered: diagnostic interpretation of MDS along the years; diagnostic incidence of MDS, AML and AP in each of the five-year periods; relative frequency of those diagnosis with respect to the total number of cases; evolutive profile of sex and age at diagnosis; quantitative significance of secondary MDS-AL and toxic AP along the years; MDS subtypes and their epidemiologic characteristics.

RESULTS

A total of 510 MDS, 610 AML and 223 AP cases were identified. With respect to the sex of the MDS patients, some changes have been seen along the years, from an M/F ratio of 1.9 to 1.0; and the mean age at diagnosis raised from 53.3 years (with only 1.7% of the cases over 65 years of age) to 71.4 years (with 76.9% of the cases over 65 years of age), all this within the 1959-1989 period. The incidence of AML and AP has remained stable for the last 20 years; on the contrary, MDS have been increasing continuously along the 35 years of the study, which poses for a higher number of new cases in every period (from 35 to 119) and also for a higher relative frequency in the registry (from 1.37% to 4.40%) within the period 1959-1989. Valuable toxic history was progressively increasing in secondary MDS-AML and progressively decreasing in AP. With respect to the FAB subtypes of MDS, and taking into account the last of the five-year periods, the most frequently diagnosed were RA and RSA followed by RAEB, CMML and RAEB-T.

CONCLUSIONS

The increment of the incidence of MDS cases correlates significantly with the increment of the patients aged over 65 years. This incidence appears to be scarcely influenced by previous mutagenic agents (radiotherapy, chemotherapy) and might be due to a better understanding of MDS.

[Idiopathic thrombocytopenic purpura in 5 members of a family]

Five cases of idiopathic thrombocytopenic purpura (ITP) appearing on five members of two generations of a family, with autosomal dominant pattern, are presented. The clinico-biologic behaviour of 2 patients (studied and treated by the authors) plus the available data from the 3 others (diagnosed and treated at other hospitals) allowed us to discard any possibility of hereditary non-immunologic thrombocytopenia. The predisposition of ITP patients and their relatives to present clinico-biological features of autoimmune diseases is commented as a possible explanation for the rare forms of familial ITP.

Bullfight: the afición

Bullfighting, as a spectacle, provides a special frame for projections, externalizations, and identifications. The central appeal of bullfighting is sadistic gratification, which seems to be of a mostly parricidal nature. The public experiences intense ambivalence toward the protagonists of the fight, who exert attraction for the id as well as for the superego. The existence of intrasystemic conflicts is pointed out. The history of bullfighting reflects the evolution of collective compromise formations between the fulfillment of sadistic drives and superego sensitivities, as influenced by changing social tolerance. The author reviews the most common rationalizations of the spectators, the sexual prototypes in bullfighting, the manifestations of envy toward the bullfighter, and the public's narcissistic regression due to the grandiose identification with him. Some associations from patients are commented upon.

Haemolytic anaemia to the alpha-interferon treatment: a proposed mechanism

Auto-immune haemolytic anaemia (AIHA) has been found in a case of alpha-interferon treatment. Serum antibody and eluate were positive in the absence of the drug. Although the patient recovered after the treatment was stopped, DAGT remained positive for at least 8 months. The mechanism proposed to explain why this drug induced AIHA is similar to that proposed for alpha-methyl-dopa. Drugs could alter the red cell membrane and impair the immune system. Such changes have been observed with alpha-interferon and were related with increased autoimmunity.

Influence of growth temperature on the production of extracellular virulence factors and pathogenicity of environmental and human strains of Aeromonas hydrophila

The biochemical properties, virulence for mice and trout, and the extracellular virulence factors at 28 degrees and 37 degrees C of 11 environmental and nine human strains of Aeromonas hydrophila were compared. All the environmental isolates and four of the human group were virulent for trout at 3 x 10(7) cfu, but only human strains were able to cause death or lesions in mice by the intramuscular route. Extracellular virulence factors such as haemolysins, cytotoxins and proteases were also investigated in supernatant fluids of cultures grown at 28 degrees C and 37 degrees C. The production of haemolysins, caseinases, elastases and growth yields of environmental strains decreased sharply during cultivation at 37 degrees C but cytotoxins were produced to the same extent, or slightly less, than at 28 degrees C. The human strains differed from the environmental strains in response to growth temperatures: protease activity decreased at 37 degrees C, although growth yield was not affected, but more haemolysins and cytotoxins were produced by the virulent strains at this temperature than at 28 degrees C. Sodium caseinate SDS-PAGE of culture supernatant fluids of selected human strains revealed that temperature selectively inhibited the production of certain proteases.

Comparative study of virulence and virulence factors of Aeromonas hydrophila strains isolated from water and sediments of a river

Seventy-four strains of Aeromonas hydrophila isolated from water and sediments of the River Porma (León, N.W. Spain) were characterized biochemically and biologically. Fifty-seven strains (77.02%) were virulent for rainbow trout (Salmo gairdneri) by intramuscular challenge but showed differing degree of pathogenicity which could not be associated with the source. A lack of correlation between caseinase, haemolytic and cytotoxic activities of the strains and their isolation source was also observed. Only two surface characters, acriflavine 0.2% agglutination and non-agglutinating SP-/PAB-phenotypes, were significantly associated with water and sediment strains, respectively.

[Severe digestive hemorrhage of an unusual etiology. Visible isolated and bleeding esophageal vessels]

We describe two patients with massive upper gastrointestinal bleeding. The upper gastrointestinal endoscopy revealed jet haemorrhage in the distal portion of the esophagus, from a visible vessel, without esophageal mucosal damage. In both cases arteriography was performed, and did not show vascular malformations or fistulous points. The patients were successfully treated, one with endoscopic sclerosis and balloon tamponade, and the other with endoscopic sclerosis and transcatheter embolization through left gastric artery. For the time being we do not know the true importance of these findings, but we hope that other reports help us to understand the clinical and pathologic features of this vascular lesion, and the best therapeutic approach.

Cloning and characterization of an extracellular temperature-labile serine protease gene from Aeromonas hydrophila

Aeromonas virulence is thought to depend on multigenic functions. The gene for an extracellular protease from Aeromonas hydrophila SO2/2 was cloned in Escherichia coli C600-1 by using pIJ860, bifunctional plasmid, as a vector. The gene encodes for a temperature-labile serine protease (P2) with a molecular mass of approx. 68 kDa which is highly inhibited by PMSF. The gene was expressed in Streptomyces lividans 1326 by transforming protoplasts with the original clone pPA2. We were also able to transfer and express the prt P2 gene in Pseudomonas putida by mating experiments. The protein P2 was secreted into the periplasms of both P. putida and E. coli C600-1 being identical in properties to one of the proteases secreted into the culture supernatant by A. hydrophila SO2/2.

Patient's surface, clinical surface, and workable surface

Surface is a term often used in clinical theory, which seems to have eluded a reliable definition. Freud used the term mostly to denote the analysand's consciousness. This patient's surface does not always coincide with the data the analyst can observe, i.e., the clinical surface. It is proposed that clinical surface be understood, in contrast to other psychoanalytic concepts, as the clinical evidence that does not need conjecture to be grasped cognitively. The concept of "average expectable apperception" is introduced. Workable surface is defined as those aspects of the clinical surface that lend themselves well to the exploration of unconscious dynamics or genesis. Ideas about which surfaces are optimally workable vary according to different schools of technique. The advantages of considering clinical surface the objective anchorage of psychoanalysis as a positive science and of differentiating it from patient's surface and workable surface are discussed.

Molecular cloning and characterization of an extracellular protease gene from Aeromonas hydrophila

A structural gene which codes for an extracellular protease in Aeromonas hydrophilia SO2/2 and D13 was cloned in Escherichia coli C600-1 by using pBR322 as a vector. The gene codes for a temperature-stable protease with a molecular mass of approximately 38,000 daltons. The protein was secreted to the periplasm of E. coli C600-1 and purified by osmotic shock. Cloned protease (P3) was identical in molecular mass and properties to the one purified from A. hydrophila SO2/2 culture supernatant as an extracellular product.

Pathogenicity factors and virulence for rainbow trout (Salmo gairdneri) of motile Aeromonas spp. isolated from a river

Ninety-seven motile Aeromonas strains were isolated over a period of a year from samples of water and sediment collected at different sites along a river. Strains were regularly recovered from all samples, regardless of the source of isolation or seasonal conditions. Isolates were biochemically characterized by the API 20NE system (Analytab Products, Plainview, N.Y.) and classified as Aeromonas hydrophila (74 strains), Aeromonas sobria (11 strains), and Aeromonas caviae (12 strains). Despite the high level of homogeneity observed in their biochemical patterns, they displayed different degrees of virulence for fish; 72.02% of A. hydrophila isolates and 63% of A. sobria isolates were virulent for fish by intramuscular challenge, but lower frequencies of virulence were observed when intraperitoneal injections were used. All A. caviae strains proved to be avirulent. Caseinases, hemolysins, and Vero cytotoxins were produced by 100, 91, and 94.59%, respectively, of A. hydrophila strains and with lower frequencies and lower caseinase activities by A. sobria isolates. No correlation was found between these activities and the degree of virulence of the strains for fish. Most hydrophobic strains seem to be concentrated in A. caviae, A. sobria, and avirulent A. hydrophila groups. Known virulence markers commonly associated with virulent strains (acriflavine negative and self-pelleting negative and precipitation after boiling positive phenotypes) had a low representation in the total of strains studied and were not associated with virulence.

[Acute promyelocytic leukemias: clinico-biological aspects, prognostic factors, therapeutic response, and possibilities of cure in 34 cases (1970-1988)]

Thirty-four new cases of acute promyelocytic leukaemia (M3) were diagnosed at the authors' Centre between 1970 and 1988 (19 males and 15 females) with ages between 5 and 73 years (median age, 32 years). Three cases were of the hypogranular variant or M3-v (8.8%). The clinical picture included: haemorrhagic diathesis (85%), pallor/malaise (82%), fever/infection (41%), hepatomegaly (26%), splenomegaly (12%). Leucopenia of less than 5 x 10(9)/L was present in 23/34 cases, laboratory signs of DIC in 26/31, increased LDH, over 400 U/mL, in 6/31, and abnormal karyotype in 7/15. One of the patients rejected any treatment; two others died of brain haemorrhage before therapy was started, and seven died in the first two weeks of treatment. Of the 31 patients treated, complete remission (CR) was achieved in 21 cases (67.7%). Allogeneic BMT was carried out in two of them, with further relapse and death. Post-remission treatment was given to the remaining 19 patients, and there were 13 relapses. Six patients have been in CR, 5 of them after cessation of therapy, for the last 1.5-11.5 years. Age under 50 years and leucocyte count below 5 x 10(9)/L at diagnosis were favourable prognostic factors according to the univariate statistical analysis performed. The survival plateau of the actuarial curve was reached beyond 2.75 years by 15% of all the patients treated (33 cases), 23% of the patients who achieved CR (21 cases), 31% of the patients under 50 years of age and 5 x 10(9)/L leucocyte count at diagnosis (15 cases) and 36% of these last achieving CR (13 cases).

Unusual serotypes of Escherichia coli from piglet diarrhea in north Spain

Eighteen strains of Escherichia coli isolated from piglet diarrhea were examined with a wide range of antisera and were found not to belong to the common serotypes found in this disease. Several different serotypes were found; nine strains belonged to O153, and an O group (not commonly associated with piglet diarrhea) belonged to four different serobiotypes.

Stereotactic evacuation and local administration in intracerebral haematomas. A comparative study

Based on current controversies on optimal treatment for spontaneous intracerebral haematomas, chronic experiments to investigate the validity of open surgery, stereotactic evacuation and local urokinase administration in these lesions were performed in 52 dogs. Under general anesthesia diverse volumes of autologous blood were intracerebrally injected to produce the haematoma. A catheter was introduced and chronically implanted in the contralateral ventricle for intracranial pressure monitoring. The animals were divided in two groups of 26 dogs each, according to haematoma location in subcortical or basal ganglia structures. The natural history was studied in both groups. Different types of treatment consisting in surgery, stereotactic evacuation, urokinase injection within the clot and both latter techniques combined were carried out 24 or 72 hours following haematoma production. Clinical status, systemic arterial pressure, intracranial pressure and CT scanning were used for result evaluation. Brain specimens were submitted for pathological examination. Our results indicate that stereotactic evacuation performed during the first 24 hours after haematoma occurrence was the most effective and innocuous procedure for basal ganglia lesions. Local urokinase plus stereotactic aspiration showed a high efficacy in controlling delayed basal ganglia and subcortical blood collections. Other therapeutic approaches behaved almost as the natural history.

Can clinical psychoanalysis be scientific?

Criticism of psychoanalysis as a scientific discipline has increased recently. Even though psychoanalytic theory deserves ample criticism by the scientific community for its ambiguous definitions, deficient construct validity and precarious operationalization of its procedures, as long as there are clinical observables susceptible of recording, psychoanalysis remains in the realm of science. The scientific merit is reviewed of some psychoanalytic concepts such as repression, the unconscious, psychic structures, and intrapsychic conflict. The possibility of objectivity, prediction, and confirmation of hypotheses is discussed.

Features of enterotoxigenic Escherichia coli strains of porcine origin that express K88 and 987P fimbrial antigens

Escherichia coli strains of porcine origin express K88 and 987P pilus-antigens in vitro. This study reports their enterotoxin producing ability, serological features and plasmid content. The bipiliated strains were enterotoxigenic and all contained a large plasmid of uniform size.

Acute lymphoblastic leukaemia in adults: results of a 'total-therapy' programme in 47 patients over 15 years old

For the last 13 years, 47 patients with ALL over 15 years old (range 15-72; median 21) entered a 'total-therapy' programme. All cases received a 6-8 week induction course of PRD, VCR, DRB and/or L-ASN. Prophylaxis of CNS was done by cranial radiotherapy plus i.t. MTX in 32/45 patients who attained complete remission (CR). After CR, subsequent therapy involved a programme of maintenance with 6MP and MTX at full doses. Pulses of intermittent reinforcement (PRD, VCR and DRB) were done for 2 weeks, every 3 months, for at least 3 years. CR was achieved in 42/47 patients (89.3%). The median relapse-free survival of the patients who attained CR was 57 months, with an 8-year estimated disease-free survival rate of 43% for those cases. If actuarial assumptions were to be sustained, it would indicate an encouraging cure rate of 38% of all our adult ALL patients (mainly in those cases between 15 and 30 years old).