Changes in morphology and physiology of an East Mediterranean sponge in different habitats

The sponge Tetilla sp. (Tetractinomorpha: Tetillidae) is a common species in the eastern Mediterranean. This sponge inhabits four different habitat types differing in wave impact and irradiance levels. Two of these habitats (a shallow cave and deep water) are characterized by relatively calm water, whereas the other two (shallow exposed site and tide pools) are in turbulent water with high energy flow. The present study examined the influence of physical (depth, illumination and water motion) and biotic factors on morphology, skeletal plasticity and reproductive traits among the four spatially separated populations. Sponges from tidal pools had significantly larger body volume than sponges from deep water and from shallow caves (ANOVA: tidal-deep P< 0.0001; tidal-shallow caves P< 0.05). Sponges from exposed habitats were significantly larger than deep-water sponges (ANOVA: P=0.01). In addition, individuals from tide pools and from the exposed habitat had a significantly higher proportion of structural silica than sponges from the calmer deep water and from the cave sites. Oxea spicules in sponges from the calm habitats were significantly shorter than in those from the tidal pools and the exposed habitats. The percentage of spicules out of a sponge's dry weight in individuals transplanted from deep (calm) to shallow (turbulent) water significantly increased by 21.9&PLUSMN; 12.9%. The new spicule percentage did not differ significantly from that of sponges originally from shallow water. Oocyte diameter differed significantly between habitats. The maximal size of mature eggs was found in deep-water sponges in June (97&PLUSMN; 5 μ m). In the shallow habitats, a smaller maximal oocyte diameter was found in the cave, in May (56.5&PLUSMN; 3 μ m). Furthermore, oocyte density in shallow-water sponges was highest in May and decreased in June (with 88.2&PLUSMN; 9 and 19.3&PLUSMN; 9 oocytes mm(-2), respectively). At the same time (June), oocyte density of deep-water sponges had just reached its maximum (155&PLUSMN; 33.7 oocytes mm(-2)). The difference in oocyte size and density between deep- and shallow-water individuals indicates an earlier gamete release in the shallow sponge population. The results suggest that plasticity in skeletal design of this sponge indicates a trade off between spicule production and investment in reproduction.

Cardiac chymase: pathophysiological role and therapeutic potential of chymase inhibitors

On release from cardiac mast cells, alpha-chymase converts angiotensin I (Ang I) to Ang II. In addition to Ang II formation, alpha-chymase is capable of activating TGF-beta 1 and IL-1 beta, forming endothelins consisting of 31 amino acids, degrading endothelin-1, altering lipid metabolism, and degrading the extracellular matrix. Under physiological conditions the role of chymase in the mast cells of the heart is uncertain. In pathological situations, chymase may be secreted and have important effects on the heart. Thus, in animal models of cardiomyopathy, pressure overload, and myocardial infarction, there are increases in both chymase mRNA levels and chymase activity in the heart. In human diseased heart homogenates, alterations in chymase activity have also been reported. These findings have raised the possibility that inhibition of chymase may have a role in the therapy of cardiac disease. The selective chymase inhibitors developed to date include TY-51076, SUN-C8257, BCEAB, NK320, and TEI-E548. These have yet to be tested in humans, but promising results have been obtained in animal models of myocardial infarction, cardiomyopathy, and tachycardia-induced heart failure. It seems likely that orally active inhibitors of chymase could have a place in the treatment of cardiac diseases where injury-induced mast cell degranulation contributes to the pathology.

Using student feedback to construct an assessment rubric for a concept map in physiology

Constructing quality assessment rubrics can be challenging, especially when they are used for integrated, group-centered, applied learning. We describe a collaborative assessment task in which groups of second-year dentistry students developed a complex concept map. In groups of four, the students were given a written, simulated, medical history of a patient and required to construct a concept map illustrating relevant pathophysiological concepts and pharmacological interventions. This report describes a research project aimed at making educational goals of the task more explicit through investigating student and faculty member understandings of the criteria that might be used to assess the concept map. Information was gathered about the perceptions of students in relation to the learning goals associated with the task. These were compared with faculty member perceptions. The findings were used to develop an assessment rubric intended to be more accessible to learners. The new rubric used the language of both faculty members and students to more clearly represent expectations of each criterion and standard. This assessment rubric will be used in 2005 for the next phase of the project.

Mind and body: Concepts of human cognition, physiology and false belief in children with autism or typical development

This study examined theory of mind (ToM) and concepts of human biology (eyes, heart, brain, lungs and mind) in a sample of 67 children, including 25 high functioning children with autism (age 6-13), plus age-matched and preschool comparison groups. Contrary to Baron-Cohen [1989, Journal of Autism and Developmental Disorders, 19(4), 579-600], most children with autism correctly understood the functions of the brain (84%) and the mind (64%). Their explanations were predominantly mentalistic. They outperformed typically developing preschoolers in understanding inner physiological (heart, lungs) and cognitive (brain, mind) systems, and scored as high as age-matched typical children. Yet, in line with much previous ToM research, most children with autism (60%) failed false belief, and their ToM performance was unrelated to their understanding of. human biology. Results were discussed in relation to neurobiological and social-experiential accounts of the ToM deficit in autism.

Widespread brain activity during an abdominal task markedly reduced after pain physiology education: fMRI evaluation of a single patient with chronic low back pain

The way people with chronic low back pain think about pain can affect the way they move. This case report concerns a patient with chronic disabling low back pain who underwent functional magnetic resonance imaging scans during performance of a voluntary trunk muscle task under three conditions: directly after training in the task and, after one week of practice, before and after a 2.5 hour pain physiology education session. Before education there was widespread brain activity during performance of the task, including activity in cortical regions known to be involved in pain, although the task was not painful. After education widespread activity was absent so that there was no brain activation outside of the primary somatosensory cortex. The results suggest that pain physiology education markedly altered brain activity during performance of the task. The data offer a possible mechanism for difficulty in acquisition of trunk muscle training in people with pain and suggest that the change in activity associated with education may reflect reduced threat value of the task.

Pathological complete response and residual DCIS following neoadjuvant chemotherapy for breast carcinoma

Patients who have no residual invasive cancer following neoadjuvant chemotherapy for breast carcinoma have a better overall survival than those with residual disease. Many classification systems assessing pathological response to neoadjuvant chemotherapy include residual ductal carcinoma in situ (DCIS) only in the definition of pathological complete response. The purpose of this study was to investigate whether patients with residual DCIS only have the same prognosis as those with no residual invasive or in situ disease. A retrospective analysis of a prospectively maintained database identified 435 patients, who received neoadjuvant chemotherapy for operable breast cancer between February 1985 and February 2003. Of these, 30 (7%; 95% CI 5-9%) had no residual invasive disease or DCIS and 20 (5%; CI 3-7%) had residual DCIS only. With a median follow-up of 61 months, there was no statistical difference in disease-free survival, 80% (95% CI 60-90%) in those with no residual invasive or in situ disease and 61% (95% CI 35-80%) in those with DCIS only (P = 0.4). No significant difference in 5-year overall survival was observed, 93% (95% CI 75-98%) in those with no residual invasive or in situ disease and 82% (95% CI 52-94%) in those with DCIS only (P = 0.3). Due to the small number of patients and limited number of events in each group, it is not possible to draw definitive conclusions from this study. Further analyses of other databases are required to confirm our finding of no difference in disease-free and overall survival between patients with residual DCIS and those with no invasive or in situ disease following neoadjuvant chemotherapy for breast cancer.

The influence of body size on the diving behaviour and physiology of the bimodally respiring turtle, Elseya albagula

In aquatic vertebrates that acquire oxygen aerially dive duration scales positively with body mass, i.e. larger animals can dive for longer periods, however in bimodally respiring animals the relationship between dive duration and body mass is unclear. In this study we investigated the relationships between body size, aquatic respiration, and dive duration in the bimodally respiring turtle, Elseya albagula. Under normoxic conditions, dive duration was found to be independent of body mass. The dive durations of smaller turtles were equivalent to that of larger individuals despite their relatively smaller oxygen stores and higher mass specific metabolic rates. Smaller turtles were able to increase their dive duration through the use of aquatic respiration. Smaller turtles had a relatively higher cloacal bursae surface area than larger turtles, which allowed them to extract a relatively larger amount of oxygen from the water. By removing the ability to respire aquatically (hypoxic conditions), the dive duration of the smaller turtles significantly decreased restoring the normal positive relationship between body size and dive duration that is seen in other air-breathing vertebrates.

The Opinion Editorial: teaching physiology outside the box

Improving the public understanding of science is an important challenge for the future professional scientists who are our current undergraduates. In this paper, we present a conceptual model that explores the role of mass media as community gatekeepers of new scientific findings. This model frames the benefits for undergraduate science students to learn about media genres so that they can learn to communicate science more effectively to nonprofessional audiences. Informed by this Media Role model, we then detail a novel writing task for undergraduate physiology students, the Opinion Editorial (Op-Ed), and an accompanying Peer Review. The Op-Ed genre was directly taught to the students by a professional journalist. As an assessment task, students presented a recent, highly technical paper as an Op-Ed. This was assessed by both faculty members and peers using a detailed assessment rubric. Most students were able to replicate the features of Op-Eds and attained high grades on their writing tasks. Survey data from final-year physiology students (n = 230) were collected before and after the implementation of the Op-Ed/Peer Review. These indicated that most students were aware of the importance of scientists to effectively communicate their knowledge to nonprofessional audiences, that the Op-Ed writing task was challenging, and that they believed that their ability to write to nonprofessional audiences was improved after explicit teaching and feedback.

The renal cortical fibroblast in renal tubulointerstitial fibrosis

Renal cortical fibroblasts have key roles in mediating intercellular communication with neighboring/infiltrating cells and extracellular matrix (ECM) and maintenance of renal tissue architecture. They express a variety of cytokines, chemokines, growth factors and cell adhesion molecules, playing an active role in paracrine and autocrine interactions and regulating both fibrogenesis and the interstitial inflammatory response. They additionally have an endocrine function in the production of epoetin. Tubulointerstitial fibrosis, the common pathological consequence of renal injury, is characterized by the accumulation of extracellular matrix largely due to excessive production in parallel with reduced degradation, and activated fibroblasts characterized by a myofibroblastic phenotype. Fibroblasts in the kidney may derive from resident fibroblasts, from the circulating fibroblast population or from haemopoetic progenitor or stromal cells derived from the bone marrow. Cells exhibiting a myofibroblastic phenotype may derive from these sources and from tubular cells undergoing epithelial to mesenchymal transformation in response to renal injury. The number of interstitial myofibroblasts correlates closely with tubulointerstitial fibrosis and progressive renal failure. Hence inhibiting myofibroblast formation may be an effective strategy in attenuating the development of renal failure in kidney disease of diverse etiology. (c) 2005 Elsevier Ltd. All rights reserved.

Trait physiology and crop modelling to link phenotypic complexity to underlying genetic systems

New tools derived from advances in molecular biology have not been widely adopted in plant breeding because of the inability to connect information at gene level to the phenotype in a manner that is useful for selection. We explore whether a crop growth and development modelling framework can link phenotype complexity to underlying genetic systems in a way that strengthens molecular breeding strategies. We use gene-to-phenotype simulation studies on sorghum to consider the value to marker-assisted selection of intrinsically stable QTLs that might be generated by physiological dissection of complex traits. The consequences on grain yield of genetic variation in four key adaptive traits – phenology, osmotic adjustment, transpiration efficiency, and staygreen – were simulated for a diverse set of environments by placing the known extent of genetic variation in the context of the physiological determinants framework of a crop growth and development model. It was assumed that the three to five genes associated with each trait, had two alleles per locus acting in an additive manner. The effects on average simulated yield, generated by differing combinations of positive alleles for the traits incorporated, varied with environment type. The full matrix of simulated phenotypes, which consisted of 547 location-season combinations and 4235 genotypic expression states, was analysed for genetic and environmental effects. The analysis was conducted in stages with gradually increased understanding of gene-to-phenotype relationships, which would arise from physiological dissection and modelling. It was found that environmental characterisation and physiological knowledge helped to explain and unravel gene and environment context dependencies. We simulated a marker-assisted selection (MAS) breeding strategy based on the analyses of gene effects. When marker scores were allocated based on the contribution of gene effects to yield in a single environment, there was a wide divergence in rate of yield gain over all environments with breeding cycle depending on the environment chosen for the QTL analysis. It was suggested that knowledge resulting from trait physiology and modelling would overcome this dependency by identifying stable QTLs. The improved predictive power would increase the utility of the QTLs in MAS. Developing and implementing this gene-to-phenotype capability in crop improvement requires enhanced attention to phenotyping, ecophysiological modelling, and validation studies to test the stability of candidate QTLs.