The Scent of Blood: A Driver of Human Behavior?

The scent of blood is potentially one of the most fundamental and survival-relevant olfactory cues in humans. This experiment tests the first human parameters of perceptual threshold and emotional ratings in men and women of an artificially simulated smell of fresh blood in contact with the skin. We hypothesize that this scent of blood, with its association with injury, danger, death, and nutrition will be a critical cue activating fundamental motivational systems relating to either predatory approach behavior or prey-like withdrawal behavior, or both. The results show that perceptual thresholds are unimodally distributed for both sexes, with women being more sensitive. Furthermore, both women and men’s emotional responses to simulated blood scent divide strongly into positive and negative valence ratings, with negative ratings in women having a strong arousal component. For women, this split is related to the phase of their menstrual cycle and oral contraception (OC). Future research will investigate whether this split in both genders is context-dependent or trait-like.     

Validation of the Finnish forest types by numerical methods illustrated by means of two sets of relevé data

Examples show that two clustering programs (GROUPAGE, TABORD) group the forest vegetation into clusters with about the same results as obtained by a traditionally working plant sociologist assigning it to the Finnish forest site types. The best result is achieved by using both of these programs together with an additional ordination program (ORDINA). The differences when all three analyses are taken into account depend on the fact that there are often some transitional relevés in the material. In a few cases a new type determination for the relevé might be justified. The clustering methods show often groupings into smaller units (variants) inside the types, units which are rarely used in the Finnish forest type system.     

Could Selenium Administration Alleviate the Disturbances of Blood Parameters Caused by Lithium Administration in Rats?

Lithium is widely used in medicine, but its administration can cause numerous side effects. The present study aimed at the evaluation of the possible application of selenium, an essential and antioxidant element, as a protective agent against lithium toxicity. The experiment was performed on four groups of Wistar rats: I (control)—treated with saline, II (Li)—treated with lithium (Li₂CO₃), III (Se)—treated with selenium (Na₂SeO₃) and IV (Li?+?Se)—treated with lithium and selenium (Li₂CO₃ and Na₂SeO₃) in the form of water solutions by stomach tube for 6 weeks. The following biochemical parameters were measured: concentrations of sodium, potassium, calcium, magnesium, phosphorus, iron, urea, creatinine, cholesterol, glucose, total protein and albumin and activities of alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase in serum as well as whole blood superoxide dismutase and glutathione peroxidase. Morphological parameters such as red blood cells, haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentration, platelets, white blood cells, neutrophils as well as lymphocytes were determined. Lithium significantly increased serum calcium and glucose (2.65?±?0.17 vs. 2.43?±?0.11; 162?±?31 vs. 121?±?14, respectively), whereas magnesium and albumin were decreased (1.05?±?0.08 vs. 1.21?±?0.15; 3.85.?±?0.12 vs. 4.02?±?0.08, respectively). Selenium given with lithium restored these parameters to values similar to those observed in the control (Ca—2.49?±?0.08, glucose—113?±?26, Mg—1.28?±?0.09, albumin—4.07?±?0.11). Se alone or co-administered with Li significantly increased aspartate aminotransferase and glutathione peroxidase. The obtained outcomes let us suggest that the continuation of research on the application of selenium as an adjuvant in lithium therapy seems warranted.     

Are Retinal Vessels Calibers Influenced by Blood Pressure Measured at the Time of Retinography Acquisition?

Background

Retinal arterial narrowing is associated with higher office blood pressure (BP) and ambulatory blood pressure monitoring, and increased incidence of cardiovascular disease, but it is still unknown if the vessel caliber is associated with BP measured at the time of retinography acquisition.

Methods

Retinal arteriolar and venular calibers were measured by the microdensitometric method in 448 patients with hypertension. Participants underwent 24-hours ambulatory blood pressure (24-h ABP) monitoring simultaneously with the retinography acquisition. Association between arteriolar and venular calibers with increase of 10 mmHg in the mean 24-hours, daily, and nightly BP, and with BP measured at the time of retinography, was evaluated by ANOVA and multivariate analyses.

Results

Mean 24-hours, daytime and nighttime systolic and diastolic BP were inversely associated with the arteriolar caliber, but not with the venular caliber. Arteriolar caliber decreased -0.8 (95% CI -1.4 to -0.2) μm per 10-mmHg increase in 24-hours mean systolic BP, adjusted for age, gender, fellow vessel, and duration of hypertension (P = 0.01). The corresponding decreasing in arteriolar caliber by 10 mmHg of increasing in mean diastolic BP was -1.1 μm (-2.0 to -0.2, P = 0.02). The decrease of arteriolar caliber by the same increasing of BP measured at the time of retinography was lower and not statistically significant, particularly for mean diastolic BP and outer arterioles calibers: -1.0 (-1.8 to -0.2) μm in the daytime BP average versus -0.3 (-0.9 to 0.3) at the moment of retinography acquisition.

Conclusions

These findings suggest that the caliber of arteriolar retinal vessels in patients with uncontrolled hypertension are not significantly influenced by blood pressure measured at the time of retinography acquisition.     

Phagocytosis of microorganisms by means of overshooting pseudopods: where do we stand?

During the endocytic uptake of particulate material such as microorganisms, the transition from the engulfment step to the internalization step of phagocytosis may be disturbed. Thus, the pseudopods flanking the particles do not close to a phagosome, but lie on top of each other. This uncoupling of pseudopod extension and phagosome formation provides useful information about the regular course of phagocytosis. Experimental models on the phenomena of coiling and overlapping phagocytosis have so far been established with legionellas, spirochetes, trypanosomatids, fungal cells, and zymosan.     

Investigations on the biodegradation of alkylpolyglucosides by means of liquid chromatography–electrospray mass spectrometry

The biodegradation of alkylpolyglucosides (APGs) was studied under the conditions of the OECD Screening Test with activated sludge as an inoculum. An influence of alkyl and sugar chain length on the biodegradation rate and a central scission pathway of the biodegradation were investigated. The liquid chromatography-electrospray mass spectrometry technique was used for alkylpolyglucoside analysis and for identification and semiquantitative determination of metabolites. It was found that APGs with a longer alkyl chain were biodegraded faster than those with a shorter one. However, a longer sugar chain caused slower biodegradation of APGs. The central scission pathway of biodegradation was also confirmed.     

Propagation of electromagnetic radiation in mitochondria?

Infanticide by primate males was considered rare if groups contain more than one adult male because, owing to lower paternity certainty, a male should be less likely to benefit from infanticide. Guided by recent evidence for strong variation of infanticide in primate multi-male groups, we modelled the conditions for when infanticide should occur for a group with a resident and an immigrant male. Setting the parameters (e.g. infant mortality, reduction of interbirth interval, life-time reproductive success, genetic representation) to fit the conditions most commonly found in nature, we develop a game-theoretic model to explore the influence of age and dominance on the occurrence of infanticide and infant defence. Male age strongly impacts the likelihood of an attack which is modified by the father's defence. If the new male is dominant he is likely to attack under most circumstances whereas a subordinate male will only attack if the father does not defend. These model scenarios fit the conditions under which infanticide is known to occur in primate multi-male groups and offer an explanation why infanticide is common in some multi-male groups and rare in others. Overall, the benefits for infanticidal males are strongly governed by a reduced interbirth interval while advantages via improved genetic representation in the gene pool contribute but a minor fraction.