How a haemosporidian parasite of bats gets around: the genetic structure of a parasite,vector and host compared

Parasite population structure is often thought to be largely shaped by that of its host. In the case of a parasite with a complex life cycle, two host species, each with their own patterns of demography and migration, spread the parasite. However, the population structure of the parasite is predicted to resemble only that of the most vagile host species. In this study, we tested this prediction in the context of a vector‐transmitted parasite. We sampled the haemosporidian parasite Polychromophilus melanipherus across its European range, together with its bat fly vector Nycteribia schmidlii and its host, the bent‐winged bat Miniopterus schreibersii. Based on microsatellite analyses, the wingless vector, and not the bat host, was identified as the least structured population and should therefore be considered the most vagile host. Genetic distance matrices were compared for all three species based on a mitochondrial DNA fragment. Both host and vector populations followed an isolation‐by‐distance pattern across the Mediterranean, but not the parasite. Mantel tests found no correlation between the parasite and either the host or vector populations. We therefore found no support for our hypothesis; the parasite population structure matched neither vector nor host. Instead, we propose a model where the parasite's gene flow is represented by the added effects of host and vector dispersal patterns.     

First epigravettian ceramic figurines from europe (vela spila, croatia)

Recent finds of 36 ceramic artifacts from the archaeological site of Vela Spila, Croatia, offer the first evidence of ceramic figurative art in late Upper Palaeolithic Europe, c. 17,500-15,000 years before present (BP). The size and diversity of this artistic ceramic assemblage indicate the emergence of a social tradition, rather than more ephemeral experimentation with a new material. Vela Spila ceramics offer compelling technological and stylistic comparisons with the only other evidence of a developed Palaeolithic ceramic tradition found at the sites of Pavlov I and Dolní Věstonice I, in the Czech Republic, c. 31,000-27,000 cal BP. Because of the 10,000-year gap between the two assemblages, the Vela Spila ceramics are interpreted as evidence of an independent invention of this technology. Consequently, these artifacts provide evidence of a new social context in which ceramics developed and were used to make art in the Upper Palaeolithic.     

Characterisation and differentiation of oligotrophic waters by culturable particle-attached and free-living bacterial communities

This study reports the development of a tool to characterise and differentiate northern Adriatic waters, particularly oligotrophic, high-salinity waters, based on the cellular fatty acids of culturable heterotrophic bacterioplankton. The growth abilities and population dominance were observed for particle-attached and free-living bacteria cultured in three types of media: Marine Broth, diluted Marine Broth (1:10) and R2 broth. Three groups of water layers were distinguished by hierarchical clustering analysis: eutrophic, oligotrophic and oligotrophic nutrient-selected. Significant differences between the resulting groups were tested by two-way ANOVA (with replication). Eutrophic layers were characterised by readily culturable particle-attached and free-living fractions of the bacterial community in all three media, all dominated by fast-growing γ-Proteobacteria. In contrast, oligotrophic water layers with low productivity had a much weaker culturability and a different population dominance for the free-living community, as compared to their attached or growth-arrested counterparts, for all media. The free-living bacteria from strictly oligotrophic environments demonstrated minimum culturability in Marine Broth, while those from selective oligotrophic environments were culturable and were dominated either by Cytophaga–Flavobacter complex, α-Proteobacteria or γ-Proteobacteria. The conclusive evidence regarding the selective and refractory nature of organic compounds in these waters demonstrates the dominant culturability of the Cytophaga–Flavobacter complex and α-Proteobacteria in free-living communities in all growth-media. The response of fatty acid dominance ratios depends significantly on the trophic state and fraction (p < 0.05), although the effect of the trophic state is completely different in attached and free fractions. Both fractions were tested separately, demonstrating a significant influence of the trophic state (p < 0.05), while the effect of the media on the fatty acid response was not significant (p > 0.05). An interaction between media and trophic status was present in the attached fraction (p < 0.05), yet this was not observed in the free fraction (p > 0.05), indicating that any systematic difference between trophic states was the same for each media tested. Accordingly, the free-living fraction of bacterioplankton is a more informative attribute and can be used solely as an indicator of the water layer trophic condition.     

Circumvention of chemotherapy-induced myelosuppression by transfer of themdr1 gene

Drug-induced myelosuppression is a frequent reason for curtailing chemotherapy in cancer patients. Rescue of myelosuppressed patients with autologous marrow transplants is reasonably advanced and permits an increase in the dose of anticancer drugs. Despite this improvement, patients often relapse with drug resistance disease. The human multidrug resistance (mdr1) gene might make it possible to render hemopoietic stem cells resistant to anticancer drugs after transfer of this gene. By introducing resistant stem cells into patients it might be possible to treat these patients repeatedly with otherwise ablative therapy. This review explores the feasibility ofmdr1 gene therapy.Abbreviations MDR multidrug resistance - ABMT autologous bone marrow transplantation - P-gp P-glycoprotein - RCR replication-competent retrovirus     

Cardiovascular effects of prorenin blockade in genetically spontaneously hypertensive rats on normal and high-salt diet

Recent reports have demonstrated a potential role of tissue prorenin in the pathogenesis of cardiovascular and renal damage. This study was designed to examine the role of prorenin in the pathogenesis of target organ damage in spontaneously hypertensive rats (SHRs), the best naturally occurring experimental model of essential hypertension. To this end, we studied 20-wk-old male SHRs receiving a normal diet and 8-wk-old male SHRs given food with 8% NaCl. One-half the rats in each group were given prorenin inhibitor (PRAM-1, 0.1 mg.kg(-1).day(-1)) via osmotic minipumps; the other half served as controls. Arterial pressure, left ventricular function, cardiovascular mass indexes, cardiac fibrosis, and renal function were examined at the end of the experiment. Arterial pressure was unaffected by PRAM-1 in rats on either regular or salt-excess diets. In those rats receiving a normal diet, the blockade of prorenin activation consistently reduced left ventricular mass but affected no other variable. Salt-loaded rats given PRAM-1 for 8 wk demonstrated (1) reduced serum creatinine level, (2) decreased left ventricular mass, (3) improved left ventricular function, and (4) reduced left ventricular fibrosis. These data demonstrated that the blockade of nonproteolytic activation of prorenin exerted significant cardiovascular and renal benefit in SHRs with cardiovascular damage produced by salt excess and suggested that the activation of cardiovascular or renal prorenin may be a major mechanism that mediates cardiac and renal damage in this form of accelerated hypertension.     

Combined action of virus injection and local tumor irradiation on tumor growth in mice

The dynamics of SCCVII transplantable tumor growth in C3H/H mice was determined after local tumor irradiation and/or virus (NDV LaSota) i.p. injection. The virus applied alone significantly suppressed tumor growth, particularly until the 19th day after tumor transplantation. Local irradiation with 30 Gy resulted in tumor disappearance followed with its regrowth about 15 days later. However, if the virus was injected after the irradiation, there was no tumor growth until the end of the 31 day observation period. It should be noted that virus application prior to local irradiation did not have any additional influence on tumor growth. Thus, the pronounced efficacy of virus applied after tumor irradiation deserves attention. It is possible that the virus injected after irradiation induced a chain of cytokine production joining the action of tumor destruction induced by irradiation. This should be further studied in clarifying the approaches to combined tumor therapy with possible cell-free vaccine production.     

An improved method for determination of gene copy numbers in transgenic mice by serial dilution curves obtained by real-time quantitative PCR assay

Precise characterization of transgene insertion is necessary for phenotype interpretation of transgenic animals. To check for the presence of deletions, estimate the number of inserted transgene copies, and in addition, identify the zygosity of transgenic mice, gene copy numbers were determined by real-time quantitative PCR. Instead of correlating tested samples to a single relative standard curve, serial dilution curves were constructed for every mouse sample. A novel statistical approach was designed in which mice with the same copy number were characterized by the adjusted group mean and standard deviation common to the target sequence. This enabled us to characterize the variability of the obtained results, statistically compare different groups of mice and estimate precision and limits of the applied method.     

Self-reported confidence, attitudes and skills in practical procedures among medical students: questionnaire study

The aim of our study was to investigate the influence of gender, loss of academic year(s), confidence and attitudes of students on the clinical experience gained by undergraduate education. The survey was conducted during 2004 and 2005 in a sample of 182 students of the 5th and the 6th year at J.J. Strossmayer University School of Medicine in Osijek. The participants were grouped and matched according to their gender, regular studying, the number of time(s) student has performed certain practical medical procedure and the self-confidence arisen by performing one. Furthermore, participants were grouped and compared due to their own assessment of their own practical and theoretical medical knowledge, courses which provide them the least and oppositely--the most practical medical knowledge and their attitude toward current medical faculty curriculum on clinical courses as well as the possibilities of improving them. Fisher's exact test and chi2-test were used to estimate statistical differences between the groups and the parameters in research, while coefficient of contingency was introduced with the aim of defining their correlation. The results showed statistically significant differences between male students who performed more practical medical procedures than female (p < 0.001), non-repeaters performed medical procedures more often than repeaters (p < 0.001, C = 0.658) while repeaters thought higher of their theoretical knowledge than non-repeaters (p < 0.005). Data analysis showed statistically significant correlation between clinical experience and the level of confidence (C = 0.944). This study confirmed influence of male gender, regular studying, better opinion about one's own practical skills and higher confidence in one's own work on greater number of clinical skills performed during undergraduate education.     

Salt loading produces severe renal hemodynamic dysfunction independent of arterial pressure in spontaneously hypertensive rats

We have previously shown that salt excess has adverse cardiac effects in spontaneously hypertensive rats (SHR), independent of its increased arterial pressure; however, the renal effects have not been reported. In the present study we evaluated the role of three levels of salt loading in SHR on renal function, systemic and renal hemodynamics, and glomerular dynamics. At 8 wk of age, rats were given a 4% (n = 11), 6% (n = 9), or 8% (n = 11) salt-load diet for the ensuing 8 wk; control rats (n = 11) received standard chow (0.6% NaCl). Rats had weekly 24-h proteinuria and albuminuria quantified. At the end of salt loading, all rats had systemic and renal hemodynamics measured; glomerular dynamics were specially studied by renal micropuncture in the control, 4% and 6% salt-loaded rats. Proteinuria and albuminuria progressively increased by the second week of salt loading in the 6% and 8% salt-loaded rats. Mean arterial pressure increased minimally, and glomerular filtration rate decreased in all salt-loaded rats. The 6% and 8% salt-loaded rats demonstrated decreased renal plasma flow and increased renal vascular resistance and serum creatinine concentration. Furthermore, 4% and 6% salt-loaded rats had diminished single-nephron plasma flow and increased afferent and efferent arteriolar resistances; glomerular hydrostatic pressure also increased in the 6% salt-loaded rats. In conclusion, dietary salt loading as low as 4% dramatically deteriorated renal function, renal hemodynamics, and glomerular dynamics in SHR independent of a minimal further increase in arterial pressure. These findings support the concept of a strong independent causal relationship between salt excess and cardiovascular and renal injury.