Schistosomiasis in Brazil: Does social development suffice?

Up to 15 years ago, when asked to identify the major public health problems of Brazil, there would be no hesitation in naming infant diarrhoea, Chagas disease and Schistosoma mansoni. While most field workers have now eliminated schistosomiasis from the list, now certainly headed by malaria, in academic and bureaucratic circles the old priorities are still maintained.     

In vitro gametogenesis: The end of egg donation?

This paper explores whether egg donation could still be ethically justified if in vitro gametogenesis (IVG) became reliable and safe. In order to do this, issues and concerns that might inform a patient’s reasoning in choosing to use donor eggs instead of IVG are explored and assessed. It is concluded that egg donation would only be ethically justified in a narrow range of special cases given the (hypothetical) availability of IVG treatment and, further, that egg donation could itself be replaced by donation through IVG techniques. Two possible criticisms of this position are then considered: Ones based on respect for patient wishes, and on loss of donor benefit. It is concluded that whilst neither argument constitutes a strong enough reason to continue with programmes of egg donation, egg‐sharing programmes could still be permitted come the advent of IVG; these could then provide a morally acceptable source of “natural” donor eggs.     

The ethics of functional genomics: same, same, but different?

Respect for human life--a notion of worth uniting all members of the human race--constitutes a sense of anthropocentrism that has long been the justification for the enrollment of animals in experimentation executed to develop therapies to alleviate human suffering. Currently, however, advances in functional genomics are causing a qualitative transformation of the rationale for medical research performed on animals. The notion of human distinctness is being fundamentally challenged when gene sequences similar to those found in humans are identified in different species. In this Opinion article, we would like to highlight an inherent tension brought about by the current developments in functional genomics: a tension between the scientific and the ethical status of gene sequences. Is it reasonable to argue that they are the same for all practical purposes but different in ethical status?     

Does proliferation capacity of lymphocytes depend on human blood types?

In vitro human lymphocyte culture methodology is well established yet certain confounding factors such as age, medical history as well as individual’s blood type may potentially modulate in vitro proliferation response. These factors have to be carefully evaluated to release reliable test report in routine cytogenetic evaluation for various genetic conditions, radiation biodosimetry, etc. With this objective, the current study was focused on analyzing the proliferation response of lymphocytes drawn from 90 individuals (21-29 years) with different blood types. The proliferation response was assessed in the cultured lymphocytes by cell cycle, mitotic index (MI), and nuclear division index (NDI) after stimulation with phytohaemagglutinin (PHA). To investigate the toxic effect on proliferation, MI was calculated in representative samples of each blood type were X-irradiated. The results showed that there was no significant difference among the cell cycle phases of lymphocytes in different blood types (P > 0.05). Similarly, both MI and NDI of lymphocytes derived from different blood types also did not show significant difference ( P > 0.05). The extensive interindividual variation within and among the blood types is likely responsible for the lack of significant difference in lymphocyte proliferation. Although spontaneous proliferation efficiency of lymphocytes of different blood types after PHA stimulation was grossly similar, the MI observed after radiation exposure showed a significant difference ( P < 0.05) indicating a differential proliferation response among the blood types. Our results suggest that the blood types did not have any impact on PHA-induced proliferation; however, a specific differential lymphocyte proliferation observed after radiation exposure needs to be considered.     

Does dietary magnesium modulate blood lipids?

In a randomized, single-blind, controlled study (400 patients aged 25-63 yr; 374 males, 26 females), 206 subjects were administered a magnesium-rich diet, and 194 subjects their usual diet, for 6 wk. Age, sex, body weight, hypertension, hyperlipidemia, smoking, obesity, diuretic therapy, and diabetes were comparable between the two groups, as were laboratory data at entry to the study. Intervention-group A received a significantly higher amount of dietary magnesium and potassium compared to group B, which received its usual diet. After 6 wk, there was a significant fall in total serum cholesterol (228.5 +/- 46.2 mg/dL), LDL cholesterol 146.5 +/- 75.5 mg/dL), and triglyceride (143.8 +/- 40.5 mg/dL) in group A compared to serum cholesterol (242.5 +/- 58.2 mg/dL), LDL cholesterol (157.0 +/- 78.4 mg/dL), and triglyceride (156.5 +/- 60.0 mg/dL) at entry to study, but no such changes in group-B subjects. HDL cholesterol showed a marginal mean decrease of 0.8 mg/dL in group B and a 2.5 mg/dL increase in group A. The changes in blood lipids were consistent with an increased intake of magnesium and with a rise in serum levels. Although a general blood-lipid-reducing effect of such a diet cannot be excluded, it is possible that dietary magnesium may have contributed to the reduction of total serum cholesterol, LDL cholesterol, and triglyceride, and the marginal rise in HDL cholesterol. More studies with longer follow-up periods are needed to confirm this observation.     

Does sodium restriction lower blood pressure?

Data from 13 randomised trials on the effect of sodium restriction on blood pressure were analysed. The hypotensive effect of sodium restriction was found to be small and restricted largely to systolic blood pressure, which fell by an average of 3.6 mm Hg (range 0.5-10.0 mm Hg). The reduction increased with age and in those with higher blood pressure. Sodium restriction therefore seems to be of limited use in those who are most eligible for non-pharmacological treatment of high blood pressure--namely, young patients with mild hypertension.     

Does rattling deter? The case of domestic dogs

Although the rattling of rattlesnakes (Crotalus and Sistrurus) is widely accepted as being aposematic, the hypothesis that rattling deters approach from the snake's potentially dangerous adversaries has not been well tested. In a controlled study using rattling recorded from captive rattlesnakes (C. oreganus helleri) and a variety of comparison sounds or no-sound controls, domestic dogs (Canis familiaris) showed no hesitation to approach camouflaged speakers projecting the recorded rattles. The dogs were equally likely to approach speakers projecting rattling as they were to approach speakers playing control sounds, or speakers that were silent. Furthermore, the dogs spent no less time in front of the speakers projecting the rattles than they did in front of speakers projecting control sounds or no sound. The dogs' reactions may not be representative of other species with whom rattlesnakes come into contact, but the data suggest a need for some circumspection about the role of rattling in the rattlesnake's defensive repertoire. Our results also suggest that dogs may be vulnerable to envenomation because they fail to react to the sound of rattling with avoidance.     

Does breeding status influence haematology and blood biochemistry of yellow-legged gulls?

We compared the haematological and biochemical values within a population of yellow-legged gulls (Larus michahellis) in the Chafarinas Islands (Northern Africa), in non-breeding (February) and breeding (May) animals. We collected blood samples from 51 adults. We found that according to the haematological data, there was a significant variation in haemoglobin content, and a higher proportion of heterophils, thrombocytes, and Haemoproteus infection in breeding individuals with a lower level in basophils. Blood biochemistry showed a higher level in plasmatic proteins, calcium, phosphorus, thiobarbituric acidreactive substances and alkaline phosphatase as well as alanine aminotransferase activity in breeding animals while cholesterol and phospholipid levels showed a lower level. There was also a sexual difference in triglycerides, albumin, thiobarbituric acid-reactive substances and alkaline phosphatase activity. Hence, the haematological and blood chemistry values of yellow-legged gulls showed some differences between breeding and non-breeding individuals as well as between sexes.     

Does gravitational pressure of blood hinder flow to the brain of the giraffe?

Vascular pressure consists of the sum of two pressures: (a) pressure developed by the pumping of the ventricles against the resistance of vessels, designated as viscous flow pressure, and (b) pressure caused by gravity, traditionally called hydrostatic, better described as gravitational pressure. In a conduit, both of these pressures must be overcome when a liquid is discharged to a higher level of gravitational potential energy. If a liquid is returned to its original level, gravity neither helps nor hinders flow because of the siphon effect. This circumstance prevails in the circulatory system. Hence, P1-P2 in the Poiseuille equation excludes gravitational pressure between those points. The long neck of the giraffe, therefore, poses no impediment to blood flow in the erect posture. The giraffe has a high aortic pressure. This is not for driving the blood to its head but is for minimizing the gravitational drop of intravascular pressure and collapse of the vessels. The cerebral circulation is protected by the cerebrospinal fluid which undergoes parallel changes in pressure with posture. Other vessels in the head are less protected by connective tissue, surrounding muscles and other structures. The high aortic pressure in the giraffe is probably caused by the high total peripheral resistance of the systemic circuit due to vascular adaptations related to the overall height of the animal.     

The Value of Emotion: How Does Episodic Prospection Modulate Delay Discounting?

Background

Humans often show impatience when making intertemporal choice for monetary rewards, preferring small rewards delivered immediately to larger rewards delivered after a delay, which reflects a fundamental psychological principle: delay discounting. However, we propose that episodic prospection humans can vividly envisage exerts a strong and broad influence on individuals'' delay discounting. Specifically, episodic prospection may affect individuals'' intertemporal choice by the negative or positive emotion of prospection.

Methodology/Principal Findings

The present study explored how episodic prospection modulated delay discounting by emotion. Study 1 showed that participants were more inclined to choose the delayed but larger rewards when they imaged positive future events than when they did not image events; Study 2 showed that participants were more inclined to choose the immediate but smaller rewards when they imaged negative future events than when they did not image events; In contrast, study 3 showed that choice preferences of participants when they imaged neutral future events were the same as when they did not image events.

Conclusions/Significance

By manipulating the emotion valence of episodic prospection, our findings suggested that positive emotion made individuals tend to choose delayed rewards, while negative emotion made individuals tend to choose immediate rewards. Only imaging events with neutral emotion did not affect individuals'' choice preference. Thus, the valence of imaged future events'' emotion might play an important role in individuals'' intertemporal choice. It is possible that the valence of emotion may affect the changed direction (promote or inhibit) of individuals'' delay discounting, while the ability to image future events affects the changed degree of individuals'' delay discounting.     

Brain donation: who and why?

Understanding what influences people to donate, or not donate, body organs and tissues is very important for the future of transplant surgery and medical research (Garrick in J Clin Neurosci 13:524–528, 2006). A previous web-based motivation survey coordinated by the New South Wales Tissue Resource Centre found that most people who participated in brain donation were young, female, educated Australians, not affiliated with any particular religion, and with a higher prevalence of medical illness than the general Australian population. It discussed the main motivating factors for brain donation to be “the benefits of the research to medicine and science”. This study has been replicated in a paper-based version to capture a broader cross-section of the general population, to find out who they are and what motivates them to donate. All consented and registered brain donors (n = 1,323) were sent a questionnaire via the post and recipients were given 3 months to complete the questionnaire and return it in a reply paid envelope. Results were entered into the original web-based survey and analyzed using SPSS version 10. Six hundred and fifty-eight questionnaires were returned completed, a response rate of 53%. The results show that people from all age groups are interested in brain donation. The over 65’s are the largest of the groups (30.7%). The majority of the participants were female (60.6%), married (49.2%) with children (65.8%), employed (52.9%) and have a tertiary education (73.3%). They were either non-religious (48.2%) or Christian (41.6%) and were mostly Australian (65.4%). Most (81%) had pledged to donate other organs and tissues for transplantation. The most commonly cited reasons for the donation were to benefit science (27.6%), to benefit medicine (23.9%), a family illness (17.5%) and to benefit the community (16.6%). This study demonstrates that people across all age groups are interested in brain donation. Recruitment of new brain donors could target the over 65 female Australians, who are not religious or Christian and who have also donated other organs and tissues for transplant purposes. It also indicates the need to make donation for research part of the national transplant donation program.     

The salvaged blood syndrome: a sequel to mechanochemical activation of platelets and leukocytes?

Disseminated intravascular coagulopathy (DIC) and/or increased vascular permeability in the lungs (ARDS) or systemic circulation (anasarca) has been seen in an occasional patient following the administration of washed autologous red cells. We have found that platelets and leukocytes, activated by the process of salvage, can contaminate such red cell suspensions. Apparently, activation begins with the mechanical deposition of platelets on the centrifuge bowl wall during the cell-concentration phase of blood salvage if there has been substantial prior dilution of the salvaged blood with saline. Electron microscopy of the deposit reveals activated, degranulated platelets lining the inner surface of the bowl. There is a preferential "homing" of specific leukocyte types to local regions of the deposit. On the basis of morphological evidence, we hypothesize that these mechanically activated platelets release leukoattractant substances, including arachidonate-rich phospholipids which trigger the oxidative burst enzymatic pathway in exposed phagocytic cells. These cells, when reinfused, cause increased vascular permeability. This presents clinically as ARDS or anasarca, whereas DIC results from reinfused platelet phospholipid plus accompanying cellular debris.     

Pacemakers in aggregation fields of Dictyostelium discoideum: does a single cell suffice?

In this paper we address the following question: can a single cell of the cellular slime mold Dictyostelium discoideum serve as a pacemaker for the aggregation phase? Whether or not this is possible is determined by the relative importance of cyclic AMP production due to self-stimulation as compared to diffusion of cyclic AMP away from the cell and extracellular degradation. We determine the conditions under which a single cell on an infinite place can emit periodic signals of cyclic AMP using a model developed previously for signal relay and adaptation in Dictyostelium. Elsewhere it has been shown that this model provides an accurate representation of the stimulus-response behavior of Dictyostelium for a variety of experimental conditions.     

The Normal Appendix on CT: Does Size Matter?

Purpose

(1) To evaluate the frequency of visualisation and measurements of the normal appendix. (2) To correlate Body Mass Index (BMI) and gender with visualisation of the normal appendix. (3) To correlate age, gender and body length with appendiceal length.

Materials and Methods

A retrospective review of 186 patients undergoing abdominal CT without suspicion of acute appendicitis was done. Frequency of visualisation and measurements (including maximal outer diameter, wall thickness, length, content, location of base and tip) of normal appendices were recorded.

Results

Prevalence of appendectomy was 34.4%. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of visualisation of the normal appendix were 76%, 94%, 96%, 67%, and 82% respectively. The mean maximal diameter of the appendix was 8.19 mm±1.6 (SD) (range, 4.2–12.8 mm). The mean length of the appendix was 81.11 mm±28.44 (SD) (range, 7.2–158.8 mm). The mean wall thickness of the appendix was 2.22 mm±0.56 (SD) (range, 1.15–3.85 mm). The most common location of the appendiceal tip was pelvic in 66% appendices. The most common location of the appendiceal base was inferior, medial, and posterior in 37%. The normal appendix contained high-density material in 2.2%. There was a significant correlation between gender and appendiceal length, with men having longer appendices than women.

Conclusion

Most normal appendices are seen at multislice CT using IV contrast. The maximal outer diameter of the normal appendix overlaps with values currently used to diagnose appendicitis on CT.     

Proteomics of blood and derived products: what's next?

Proteomics has changed the way proteins are analyzed in living systems. This approach has been applied to blood products and protein profiling has evolved in parallel with the development of techniques. The identification of proteins belonging to red blood cell, platelets or plasma was achieved at the end of the last century. Then, the questions on the applications emerged. Hence, several studies have focused on problems related to blood banking and products, such as the aging of blood products, identification of biomarkers, related diseases and the protein-protein interactions. More recently, a mass spectrometry-based proteomics approach to quality control has been applied in order to offer solutions and improve the quality of blood products. The current challenge we face is developing a closer relationship between transfusion medicine and proteomics. In this article, these issues will be approached by focusing first on the proteome identification of blood products and then on the applications and future developments within the field of proteomics and blood products.