Infection of mollusks and fish by the trematode Apophallus muehlingi (Jagerskiold, 1898) and its interrelations with intermediate hosts

In the Rybinsk Reservoir (Upper Volga basin), a sharp decrease in the occurrence of Apophallus muehlingi (Jagerskiold) parthenites was found in the population of the Ponto-Caspian snail Lithoglyphus naticoides Pfeiffer in 2009–2010. In the muscles of cyprinid underyearlings (ide Leuciscus idus (L.) and dace Leuciscus leuciscus (L.)), interspecific differences in protein content were revealed following their infection by metacercariae in the experimental environment. The helminth infection caused an increase in glycogen content in both fish species. A reduction of motor activity induced by muscle damage might be the main reason for the observed changes in biochemical characteristics.     

Meaning, Medicine, and the "Placebo Effect"

Meaning, Medicine, and the "Placebo Effect" Daniel Moerman Cambridge: Cambridge University Press, 2002. xiii. 172 pp.     

Methylmercury levels in a parasite (<Emphasis Type="Italic">Apophallus brevis</Emphasis> metacercariae) and its host,yellow perch (<Emphasis Type="Italic">Perca flavescens</Emphasis>)

The biomagnification of methylmercury (MeHg) amongst trophic levels results in high levels of this compound in many freshwater fish species. The role of parasites in MeHg cycling and trophic transfer in freshwater systems is largely unknown. This study examined the potential for metacercariae of Apophallus brevis to accumulate and biomagnify MeHg from their second intermediate host, yellow perch, Perca flavescens. Contrary to our prediction that MeHg levels would be higher in parasites than in the host muscle tissue in which they are embedded, we found that concentrations were similar. The lack of increase in MeHg levels from host to parasite may be due to limited assimilation of host muscle tissue or, in part, to low parasite metabolism. Parasite load did not reduce fish growth and subsequently alter MeHg concentrations. This study suggests that relationships between larval parasites and their hosts do not conform to typical patterns of MeHg biomagnification seen in aquatic systems.     

Occurrence of partenites in mollusks and the influence that metacercaria of <Emphasis Type="Italic">Apophallus muehlingi</Emphasis> (Jagerskiold, 1898) and <Emphasis Type="Italic">Posthodiplostomum cuticola</Emphasis> (Nordmann, 1832) has on some biochemical parameters in fish

A heavy parasitic load from trematode partenites of Apophallus muehlingi (Jagerskiold, 1898) was observed in the mollusk population of Lithoglyphus naticoides (Pfeiffer) after its natural invasion into the Rybinsk Reservoir. An elevated concentration of glycogen was detected in the muscles of infected fish, both in the natural populations and under experimental conditions. Interspecific differences were found for the protein concentrations when elevated concentrations were observed in the muscles of the infected roach, and no differences were discovered for the goldfish (both infected and parasite-free). The ties between the biochemical parameters and motor activity are discussed for the infected fish.     

Decision making in the NICU--strategies,statistics, and "satisficing"

As science progresses, new issues in bioethics grab the headlines, but in neonatal medicine communication and decision making for sick and premature infants is as important today as it was thirty years ago. Decisions have to be made and made well, despite suboptimal time, data, or knowledge. To this end, the authors propose good communication and a cooperative model as key to interpreting the best interest standard in a way that respects parental rights and responsibility and allows best interest to be decided from an amalgam of medical facts and human values.     

"Sweeping up after the parade": professional, ethical, and patient care implications of "turfing"

"Turfing" denotes a patient transfer or triage from one physician to another when the care of that patient feels more troublesome than it is worth. A widespread phenomenon in medical training programs, turfing appears to allocate patient care to meet physicians' rather than patients' needs. Although turfing reportedly causes inter-physician discord and inter-specialty stereotyping, its deeper consequences are poorly understood. Turfing is an interpersonal conflict masquerading as a medical issue. After examining turfing alongside other patient-related slang, I analyze the distinction between "the turf," a person, and "to turf," a practice. Several explanatory models from medical practice are explored in order to illuminate turfing's implications for medical professionalism, ethics, and patient care. I suggest that a physician's medical specialty or practice type--that is, professional culture--may link to that physician's degree of altruism. If so, then what it means fundamentally to be a physician might vary across medical specialties. Such a link calls for a new notion of cultural competence, one that physicians may apply not to patients but to each other.     

Identification of the bacteriochlorophylls, carotenoids, quinones, lipids, and hopanoids of "Candidatus Chloracidobacterium thermophilum"

"Candidatus Chloracidobacterium thermophilum" is a recently discovered chlorophototroph from the bacterial phylum Acidobacteria, which synthesizes bacteriochlorophyll (BChl) c and chlorosomes like members of the green sulfur bacteria (GSB) and the green filamentous anoxygenic phototrophs (FAPs). The pigments (BChl c homologs and carotenoids), quinones, lipids, and hopanoids of cells and chlorosomes of this new chlorophototroph were characterized in this study. "Ca. Chloracidobacterium thermophilum" methylates its antenna BChls at the C-8(2) and C-12(1) positions like GSB, but these BChls were esterified with a variety of isoprenoid and straight-chain alkyl alcohols as in FAPs. Unlike the chlorosomes of other green bacteria, "Ca. Chloracidobacterium thermophilum" chlorosomes contained two major xanthophyll carotenoids, echinenone and canthaxanthin. These carotenoids may confer enhanced protection against reactive oxygen species and could represent a specific adaptation to the highly oxic natural environment in which "Ca. Chloracidobacterium thermophilum" occurs. Dihydrogenated menaquinone-8 [menaquinone-8(H(2))], which probably acts as a quencher of energy transfer under oxic conditions, was an abundant component of both cells and chlorosomes of "Ca. Chloracidobacterium thermophilum." The betaine lipid diacylglycerylhydroxymethyl-N,N,N-trimethyl-β-alanine, esterified with 13-methyl-tetradecanoic (isopentadecanoic) acid, was a prominent polar lipid in the membranes of both "Ca. Chloracidobacterium thermophilum" cells and chlorosomes. This lipid may represent a specific adaptive response to chronic phosphorus limitation in the mats. Finally, three hopanoids, diploptene, bacteriohopanetetrol, and bacteriohopanetetrol cyclitol ether, which may help to stabilize membranes during diel shifts in pH and other physicochemical conditions in the mats, were detected in the membranes of "Ca. Chloracidobacterium thermophilum."     

Experimental evolution, loss-of-function mutations, and "the first rule of adaptive evolution"

Adaptive evolution can cause a species to gain, lose, or modify a function; therefore, it is of basic interest to determine whether any of these modes dominates the evolutionary process under particular circumstances. Because mutation occurs at the molecular level, it is necessary to examine the molecular changes produced by the underlying mutation in order to assess whether a given adaptation is best considered as a gain, loss, or modification of function. Although that was once impossible, the advance of molecular biology in the past half century has made it feasible. In this paper, I review molecular changes underlying some adaptations, with a particular emphasis on evolutionary experiments with microbes conducted over the past four decades. I show that by far the most common adaptive changes seen in those examples are due to the loss or modification of a pre-existing molecular function, and I discuss the possible reasons for the prominence of such mutations.     

Skeletal biology,functional asymmetry and the origins of "Handedness"

The past decade has witnessed the (re)emergence of a debate as to whether handedness is apomorphic within hominins. There are both qualitative and quantitative arguments, some which draw non-human primates into the handed sphere and others which exclude them. Ultimate questions concern origins of structural asymmetry of both brain and body and lateralized behaviours with implications for tool use and language. Lateralization is thus an important realm of phylogenetic study, and archaeologists and psychologists alike have sought to identify handedness within material culture. However, hand preference for tool manufacture and use among extant non-human primates, such as Cebus and Pan, suggests that the archaeological record may well be mute regarding the origins of laterality. In this paper, an argument is put forward positioning skeletal biology as a viable approach to the handedness origins issue. Behaviour is a mediator of the complementary processes of geometric modelling (change in size and shape) and histological remodelling (disuse osteopenia; microfracture repair); therefore, directional asymmetry in the pattern of skeletal modelling and remodelling is a putative signal of lateralized activity.