Biological individuality and disease

The concept of predisposition in medicine is ancient, and the term diathesis was used to express it since the days of Hippocrates and, especially, of Galen.The concept of diathesis was enormously popular throughout the nineteenth century, despite the vagueness of its actual meaning. It was clarified only in the early years of the twentieth century (1902), when it was however losing its clinical relevance, by a replacement of the concept ofchemical individuality by A.E. Garrod, followed thirty years later by the concept ofinborn factors in disease (1931).Molecular knowledge of the biological individuality of human beings, highlighted particularly by the discovery of the MHC (Major Histocompatibility Complex) during the last 30–35 years, and substantially HLA (Human Leukocyte Antigens), has offered a new and better understanding of the relationship between theself and thenot-self, as well as of various diseases, especially if they are favored by some immune dyshomeostatis.Extensive knowledge oftransplants-their immune fate of take or rejection, possibly of GVHD-have allowed mankind to consider each human being as abiological Ego, unique in his antigenic-molecular structure. But most of all, the demonstration of the fact that certain HLA antigens can be significantly associated with a greater predisposition, on the part of individuals bearing these antigens, toward contracting certain diseases, reconsiders in precise molecular terms the concept of predisposition and therefore, perhaps, in a new light, even the concept of diathesis, providing an actual logical basis for it.     

Unilateral microfibrillar abnormalities in a case of asymmetric Marfan syndrome.

The Marfan syndrome is a dominantly inherited connective-tissue disorder characterized by ocular, cardiovascular, and musculoskeletal abnormalities. Although the underlying biochemical and molecular defect(s) of this pleiotropic disease is currently unknown, we have consistently observed apparent diminished content of elastin-associated microfibrillar fibers accumulating in skin, or produced by cultured fibroblasts, from patients with the Marfan syndrome and have documented the cosegregation of these immunofluorescent abnormalities of microfibrillar fibers with the Marfan syndrome phenotype in family studies. Recently, an unusual patient has been described with unilateral phenotypic features of the Marfan syndrome, providing an unique opportunity to compare microfibrillar fibers and other connective-tissue components between the affected and nonaffected sides. In the present report, we demonstrate striking differences in apparent content of microfibrillar fibers, as determined by indirect immunofluorescence of skin and fibroblast cultures, that are revealed when multiple homologous samples derived from different sides of the patient's body are compared. In contrast, no differences in apparent content of type III collagen or in the biosynthesis and apparent structure of types I and III (pro)collagens were found. HLA types and chromosome heteromorphisms were identical in fibroblasts from both sides of the body, eliminating the formal possibility of chimerism and suggesting that a postzygotic mutation accounts for the asymmetric manifestation of the Marfan syndrome in this patient. The observation of striking decreases in microfibrillar fibers on the affected side of the body provides further evidence that abnormalities of this component of the elastic fiber system may be central to the pathogenesis and possibly the etiology of the Marfan syndrome.     

The resilience of pollination interactions: importance of temporal phases

AimsThe loss of species that engage in close ecological interactions, such as pollination, has been shown to lead to secondary extinctions, ultimately threatening the overall ecosystem stability and functioning. Pollination studies are currently flourishing at all possible levels of interaction organization (i.e., species, guild, group and network), and different methodological protocols aimed to define the resilience of pollination interactions have been proposed. However, the temporal dimension of the resilience of pollination interactions has been often overlooked. In the light of these considerations, we addressed the following questions: does a temporal approach help to reveal critical moments during the flowering season, when pollination interactions are less resilient to perturbations? Do pollination interactions evaluated at species, guild, group and network level show different patterns when assessed through time?     

The constitutively active N111G-AT1 receptor for angiotensin II modifies the morphology and cytoskeletal organization of HEK-293 cells

The expression of a constitutively active G protein-coupled receptor is expected to trigger diverse cellular changes ranging from normal to adaptive responses. We report that confluent HEK-293 cells stably expressing the constitutively active mutant N111G-AT1 receptor for angiotensin II spontaneously exhibited dramatic morphological changes and cytoskeletal reorganization. Phase-contrast microscopy revealed that these cells formed a dense monolayer, whereas cells expressing the WT-AT1 receptor displayed large intercellular spaces and numerous filopodia. Confocal microscopy revealed an elaborate web of polymerized actin at the apical and basolateral surfaces of cells expressing the N111G-AT1 receptor. Interestingly, these phenotypic changes were prevented by culturing the cells in the presence of the inverse agonist EXP3174. Similar morphologic rearrangements and de novo polymerized actin structures were found in Ang II-stimulated cells expressing the WT-AT1 receptor. We further showed that AT1 receptor-induced cell-cell contact formation did not require an increase in intracellular Ca2+ concentration or the activity of protein kinase C. However, pretreatment with Y-27632 revealed that Rho-kinase activity was required for cell-cell contact formation upon AT1 receptor activation. These observations demonstrate that the expression of the constitutively active mutant N111G-AT1 receptor had a significant impact on the morphology and cytoskeletal organization of HEK-293 cells, possibly via a mechanism involving the activity of Rho-kinase.     

Biofeedback in treatment of urinary incontinence in stroke patients

Urinary incontinence can occur poststroke owing to weakness or incoordination of sphincter muscles, impaired bladder sensation, or hyperreflexic, neurogenic bladder. Four male subjects who had urinary incontinence associated with a stroke that had occurred 8 months to 10 years earlier, and who averaged 1.6 to 7.5 accidental voidings per week, participated in an outpatient study with a 4-week scheduled-voiding baseline, 2 to 5 sessions of biofeedback-assisted bladder retraining, and 6- to 12-month follow-up. Training sessions included stepwise filling of the bladder and manometric feedback display of bladder pressure, abdominal pressure, and external anal sphincter pressure. Training procedures were designed to teach subjects to attend to bladder sensations, inhibit bladder contractions, and improve voluntary sphincter muscle control. All four subjects achieved and maintained continence regardless of substantial differences in subject characteristics, including laterality of stroke, degree of sensory impairment, and independence in daily activities.     

Behavioral and electrophysiological responses of Tetropium fuscum (Coleoptera: Cerambycidae) to pheromone and spruce volatiles

The brown spruce longhorn beetle, Tetropium fuscum (F.), is an invasive wood-boring species in eastern Canada. Gas chromatographic/electroantennographic (GC/EAD) analyses of Norway and red spruce volatiles detected a number of consistent EAD-active responses to compounds that are known to be stress-induced in spruce. The effects of these EAD-active compounds on various aspects of adult behavior were tested. In two-choice olfactometer assays, a monoterpene spruce blend, (R)-(-)-linalool, (3Z,6E)-α-farnesene, (E)-β-farnesene and spruce essential oil were attractive to both sexes. However, when they were combined with the male-produced pheromone (fuscumol), they elicited a sex-specific response: females were significantly attracted to combinations of fuscumol plus either (3Z,6E)-α-farnesene, (E)-β-farnesene and spruce essential oil but males were not. Fuscumol alone was unattractive to either sex in the olfactometer. Males exposed to fuscumol, (3Z,6E)-α-farnesene, or a combination of both, but not (E)-β-farnesene, were more likely to engage in the pheromone calling posture relative to controls. Both the monoterpene spruce blend and spruce essential oil elicited significantly greater trap capture of both sexes of T. fuscum in the presence of fuscumol and ethanol than (3Z,6E)-α-farnesene or (R)-(-)-linalool, which did not elicit trap capture alone or in combination with fuscumol. The data support the hypothesis that stress-induced sesquiterpene components, such as (3Z,6E)-α-farnesene, are important for mediating close-range attraction and behavior in T. fuscum while the monoterpene components are important for long-range processes (trap capture).     

Stem cells are differentially regulated during development, regeneration and homeostasis in flatworms

The flatworm stem cell system is exceptional within the animal kingdom, as totipotent stem cells (neoblasts) are the only dividing cells within the organism. In contrast to most organisms, piwi-like gene expression in flatworms is extended from germ cells to somatic stem cells. We describe the isolation and characterization of the piwi homologue macpiwi in the flatworm Macrostomum lignano. We use in situ hybridization, antibody staining and RNA interference to study macpiwi expression and function in adults, during postembryonic development, regeneration and upon starvation. We found novelties regarding piwi function and observed differences to current piwi functions in flatworms. First, macpiwi was essential for the maintenance of somatic stem cells in adult animals. A knock-down of macpiwi led to a complete elimination of stem cells and death of the animals. Second, the regulation of stem cells was different in adults and regenerates compared to postembryonic development. Third, sexual reproduction of M. lignano allowed to follow germline formation during postembryonic development, regeneration, and starvation. Fourth, piwi expression in hatchlings further supports an embryonic formation of the germline in M. lignano. Our findings address new questions in flatworm stem cell research and provide a basis for comparison with higher organisms.     

Monarda fistulosa hydrolate as antimicrobial agent in artificial media for the in vitro rearing of the tachinid parasitoid Exorista larvarum

Exorista larvarum (L.) (Diptera: Tachinidae), a larval parasitoid of Lepidoptera, can be reared from egg to fecund adult on artificial media composed of crude components. The standard in vitro culture is performed in 24‐well plastic rearing plates. Exorista larvarum eggs, removed from superparasitized larvae of Galleria mellonella (L.) (Lepidoptera: Pyralidae), are individually placed in the wells, each containing a cotton swab soaked in liquid medium. The plates are then sealed until parasitoid puparium formation. To avoid contamination by microorganisms, the artificial medium is routinely supplemented with 0.01% solution of gentamicin. Experiments were carried out to assess whether this broad‐spectrum antibiotic may be replaced with hydrolate of Monarda fistulosa L. (Lamiaceae), which was selected due to its high in vitro activity against pathogenic microorganisms for humans and plants. The hydrolate was either supplemented to the artificial medium (0.5% wt/wt) (first experiment) or placed in an empty well (200 μl) of the rearing plate, to be supplied as saturated air due to evaporation (second experiment). In both experiments, a standard medium with gentamicin and an antimicrobial‐free medium were maintained as positive and negative controls, respectively. In the first experiment, in the hydrolate‐supplemented medium fewer E. larvarum completed egg‐to‐adult development than in the standard medium, but significantly more parasitoids developed from egg to adult compared to the antimicrobial‐free medium. No significant difference was found between the numbers of eggs laid by the females obtained from the standard medium vs. those from the hydrolate‐supplemented medium. In the second experiment, the hydrolate‐saturated air significantly decreased E. larvarum egg hatching, puparium formation, and female fecundity compared to the standard medium. In perspective, M. fistulosa hydrolate supplemented to the artificial media for E. larvarum may be considered as a promising candidate to replace the gentamicin solution, as suggested also by the microbiological analyses of the media, performed at various growth stages of the parasitoid in a separate trial. Conversely, the hydrolate‐saturated air treatment was deemed unsuitable.