Why is there discordant diversity in sengi (Mammalia: Afrotheria: Macroscelidea) taxonomy and ecology?

The seventeen species of sengis or elephant-shrews form a well-defined clade of mammals endemic to Africa that occupy the extremes of terrestrial habitats, from coastal deserts to montane forests. Because of their isolation on Africa soon after the break-up of Gondwanaland, theoretically sengis initially evolved with little competition from other placental radiations. Their life history features include myrmecophagy, saltatorial gaits, no or limited use of nests, social monogamy, small litters of precocial young and absentee maternal care of neonates. These traits together are unique to the Macroscelidea and represent a wedding of features usually associated with either small antelopes or anteaters. Combined, these features define an adaptive syndrome that presumably has been relatively immune to competition from contemporary mammals, partially due to phylogenetic inertia. Yet paradoxically, the syndrome is well suited to a wide range of terrestrial habitats, resulting in low taxonomic diversity. Because of their unusual phylogeny and low species diversity, conservation interest is high for those sengis with relatively low densities in fragmented forests.     

Widespread alterations in central noradrenaline,dopamine, and serotonin systems in the Brattleboro rat not related to the local absence of vasopressin

A comprehensive study of monoamine transmitter and metabolite concentrations measured by HPLC was undertaken in female (vasopressin-deficient) Brattleboro rats as compared to Long Evans rats. Noradrenaline was significantly increased in 8 out of 13 dissected brain regions, whereas concentrations of the metabolite 3-methoxy-4-hydroxyphenylglycol were not altered. The increases were not restricted to areas which are normally innervated by vasopressin-containing neurons. Serotonin was increased in 6 and dopamine in 4 regions and this was accompanied in some areas by increases in the metabolites 5-hydroxyindolacetic acid and dihydroxyphenylacetic acid. Only in the striatum, cerebellum, and the medulla-pons no changes could be detected in any of the compounds of interest. These results show that the long term absence of vasopressin in Brattleboro rats appears to be associated with increases in monoamine transmitter contents and decreased metabolite/transmitter ratios. The regional distribution of these changes does not bear any relationship to the regional distribution of vasopressin cell bodies or nerve endings.     

The Patient-Provider Relationship Is Associated with Hepatitis C Treatment Eligibility: A Prospective Mixed-Methods Cohort Study

Hepatitis C virus (HCV) treatment has the potential to cure the leading cause of cirrhosis and hepatocellular carcinoma. However, only those deemed eligible for treatment have the possibility of this cure. Therefore, understanding the determinants of HCV treatment eligibility is critical. Given that effective communication with and trust in healthcare providers significantly influences treatment eligibility decisions in other diseases, we aimed to understand patient-provider interactions in the HCV treatment eligibility process. This prospective cohort study was conducted in the VA Pittsburgh Healthcare System. Patients were recruited after referral for gastroenterology consultation for HCV treatment with interferon and ribavirin. Consented patients completed semi-structured interviews and validated measures of depression, substance and alcohol use, and HCV knowledge. Two coders analyzed the semi-structured interviews. Factors associated with patient eligibility for interferon-based therapy were assessed using multivariate logistic regression. Of 339 subjects included in this analysis, only 56 (16.5%) were deemed eligible for HCV therapy by gastroenterology (GI) providers. In the multivariate logistic regression, patients who were older (OR = 0.96, 95%CI = 0.92–0.99, p = .049), reported concerns about the GI provider (OR = 0.40, 95%CI = 0.10–0.87, p = 0.02) and had depression symptoms (OR = 0.32, 95%CI = 0.17–0.63, p = 0.001) were less likely to be eligible. Patients described barriers that included feeling stigmatized and poor provider interpersonal or communication skills. In conclusion, we found that patients’ perceptions of the relationship with their GI providers were associated with treatment eligibility. Establishing trust and effective communication channels between patients and providers may lower barriers to potential HCV cure.     

Early stem cell aging in the mature brain

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Interaction of liposomes with Kupffer cells in vitro

We investigated the interaction of liposomes with rat Kupffer cells in monolayer maintenance culture. The liposomes (large unilamellar vesicles, LUV) were composed of 14C-labelled phosphatidylcholine, cholesterol and phosphatidylserine (molar ratio 4:5:1) and contained either 3H-labelled inulin or 125I-labelled bovine serum albumin as a non-degradable or a degradable aqueous space marker, respectively. After 2-3 days in culture the cells exhibited optimal uptake capacity. The uptake process showed saturation kinetics, maximal uptake values amounting to 2 nmol of total liposomal lipid/h/10(6) cells. This is equivalent to 1500 vesicles per cell. The presence of fetal calf serum (FCS) during incubation increased uptake nearly two-fold, whereas freshly isolated rat serum had no effect. The binding of the liposomes to the cells caused partial release of liposomal contents (about 15-20%) both at 4 degrees C and at 37 degrees C. In the presence of metabolic inhibitors the uptake at 37 degrees C was reduced to about 20% of the control values. Inulin and lipid label became cell-associated at similar rates and extents, whereas the association of albumin label gradually decreased after attaining a maximum at relatively low values. When, after 1 h incubation, the liposomes were removed continued incubation for another 2 h in absence of liposomes led to an approx. 30% release of cell-associated lipid label into the medium in water-soluble form. Under identical conditions as much as 90% of the cell-associated albumin label was released in acid-soluble form. Contrarily, the inulin label remained firmly cell-associated under these conditions. From these results we conclude that Kupffer cells in monolayer culture take up liposomes primarily by way of an adsorptive endocytic mechanism. This conclusion was confirmed by morphological observations on cells incubated with liposomes containing fluorescein isothiocyanate (FITC) dextran or horseradish peroxidase as markers for fluorescence microscopy and electron microscopy, respectively.     

Abuse History is related to Autonomic Regulation to Mild Exercise and Psychological Wellbeing

We investigated the potential impact of abuse history on autonomic regulation and psychological wellbeing in a sample of women who reported a history of abuse without Post Traumatic Stress Disorder. To measure autonomic regulation, heart rate data was collected before and after the participant rode a stationary bike for one mile. We found that abuse history was associated with less vagal regulation of the heart (i.e., respiratory sinus arrhythmia) and an inability to rapidly re-engage vagal regulation immediately following mild exercise to support a calm physiological state. These findings are consistent with clinical impressions that abused individuals may have a lower threshold to express fight/flight behaviors in response to stress and have difficulty shifting from mobilization to calmness. We also found that abuse history was related to psychological wellbeing. Women with an abuse history reported a greater use of dysfunctional coping methods and lower self-concept. Further, analyses indicated that there was a cumulative effect, whereby women who reported more recent abuse reported using more dysfunctional coping methods, having more mood disturbance, and lower self-concept. The findings underscore the importance of evaluating both the psychological and physiological effects of trauma, even in the absence of a diagnosis of PTSD.