Making sense of epidemiological studies of young children exposed to thimerosal in vaccines

ObjectiveTo compare epidemiological studies dealing with neurological issues (compatible with Hg toxicity) linked to exposing newborns and infants to intramuscular doses of preservative-Hg resulting from vaccination with thimerosal-containing vaccines (TCV).MethodsMajor databases were searched for studies that addressed neurodevelopment outcomes other than autism. Eight studies were identified and compared.ResultsInformation extracted from the studies done in the USA, the UK, and Italy is important in understanding the complex interplay of variables but insufficient to establish non-toxicity for infants and young children still receiving TCV: a) there is ambiguity in some studies reporting neurodevelopment outcomes that seem to depend on confounding variables; b) the risk of neurotoxicity due to low doses of thimerosal is plausible at least for susceptible infants; c) there is a need to address these issues in less developed countries still using TCV in pregnant mothers, newborns, and young children.ConclusionsSince the use of TCV is still inevitable in many countries, this increases the need to protect vulnerable infants and promote actions that strengthen neurodevelopment. Developing countries should intensify campaigns that include breastfeeding among efforts to help prime the central nervous system to tolerate exposure to neurotoxic substances, especially thimerosal-Hg.     

Attention to novelty in behaviorally inhibited adolescents moderates risk for anxiety

Background:  Individual differences in specific components of attention contribute to behavioral reactivity and regulation. Children with the temperament of behavioral inhibition (BI) provide a good context for considering the manner in which certain components of attention shape behavior. Infants and children characterized as behaviorally inhibited manifest signs of heightened orienting to novelty. The current study considers whether this attention profile moderates risk for clinical anxiety disorders among adolescents with a history of BI.
Methods:  Participants were assessed at multiple time points for BI, beginning in early childhood. At adolescence, event-related potentials (ERPs) were recorded during a three-stimulus auditory novelty oddball task, which employed frequent standard and infrequent deviant tones as well as a set of complex, novel sounds. Clinical diagnosis was carried out using the Schedule for Affective Disorders and Schizophrenia for School-Age Children-Present and Lifetime Version (K-SADS-PL). P3 and mismatch negativity (MMN) components were examined at midline frontal, central, and parietal electrode sites.
Results:  Individuals who displayed high levels of BI during childhood and increased P3 amplitude to novelty in adolescence were more likely to have a history of anxiety disorders compared to behaviorally inhibited adolescents with lower P3 amplitudes. Groups did not differ on measures of MMN.
Conclusions:  Increased neural responses to novelty moderate risk for anxiety disorders amongst individuals with a history of BI.     

Zinc and nociception: a pharmacological approach

In the last decade, neurophysiological research regarding nociceptive mediation seems to suggest a possible new approach in pain management--zinc applicability. Immunohistochemical studies prove that zinc can be found in central nervous system, inside structures active in nociception. Zinc stabilizes primary afferent C fibers, nervous fibers involved in nociception. However, this phenomenon is probably only true for extreme zinc concentrations--excess or deficit. Electrophysiological studies indicate that zinc inhibits NMDA receptors, while potentiating the activity of non-NMDA receptors. All these are arguments supporting the existence of a role of endogenous zinc regarding pain transmission.     

Monounsaturated Fat and Cardiovascular Risk

On the basis of the information discussed in this review, we can conclude that the effects of a high intake of monounsaturated fatty acids (MUFA) from olive oil include a wide range of healthy benefits beyond improvement in cholesterol levels, suggesting that this type of diet has great potential in preventing cardiovascular disease. MUFA-enriched diets reduce insulin requirements and decrease plasma concentrations of glucose and insulin in type 2 diabetic patients, unlike high-saturated fatty acid and low-fat, high-carbohydrate diets. Moreover, some data show that this dietary model could have a hypotensive effect. There is also substantial evidence that oleic-enriched low-density lipoprotein (LDL) is more resistant to oxidative modifications and that dietary MUFA may influence various components and functions related to the endothelium. These include endothelium-dependent vasodilatation and a reduced capacity of oleicenriched LDL to promote the adhesion and chemotaxis of monocytes. On the other hand, a MUFA diet decreases the prothrombotic environment, modifying platelet adhesion, coagulation, and fibrinolysis. Its reducing effect on PAI-1 plasma levels is of particular relevance. This wide range of anti-atherogenic effects could explain the low rate of cardiovascular mortality found in Mediterranean countries, where there is a moderate to high supply of dietary MUFA. Future studies need to focus on uncovering the mechanisms by which the Mediterranean diet exerts its beneficial effects     

Influenza Vaccination in Orthotopic Liver Transplant Recipients: Absence of Post Administration ALT Elevation

Influenza vaccination has reduced life-threatening complications from influenza virus infection in adult liver transplant recipients. We evaluated changes in aminotransferase level and immunogenicity of influenza vaccination in liver transplant recipients. Fifty-one liver transplant recipients were administered a standard dose of the 2002-2003 inactivated trivalent influenza vaccine. ALT values were measured at baseline, 1 week and 4-6 weeks postvaccination. Antibody responses to each component of the vaccine were measured at baseline and after 4-6 weeks by a hemagglutination inhibition (HAI) assay. Response was defined as an HAI titer > or = 1: 40 and/or a 4-fold increase in antibody titers from baseline. An ALT elevation was defined as a rise of > or = 50% from baseline. There was no difference in the median rise in ALT value between seroconverters and nonseroconverters. A significant number of recipients developed potentially protective antibody titers (p-value < 0.0001). At less than 4 months post transplantation, 1/7 (14%), at 4-12 months, 6/9 (67%), and after 12 months, 30/35 (86%) subjects responded to the H1 strain. Of 51 recipients, one HCV (-) recipients vaccinated within 3 months of transplantation developed acute cellular rejection. Influenza virus vaccination is not associated with allograft rejection or ALT flares in liver transplant recipients.     

Differential Willingness to Undergo Smallpox Vaccination Among African-American and White Individuals

OBJECTIVE:  To examine potential disparities in willingness to be vaccinated against smallpox among different U.S. racial/ethnic groups.
DESIGN:  Cross-sectional survey using an experimental design to assess willingness to be vaccinated among African Americans compared to whites according to 2 strategies: a post-exposure "ring vaccination" method and a pre-exposure national vaccination program.
SETTING:  Philadelphia County district courthouse.
PARTICIPANTS:  Individuals awaiting jury duty.
MEASUREMENTS:  We included 2 scenarios representing these strategies in 2 otherwise identical questionnaires and randomly assigned them to participants. We compared responses by African Americans and whites.
MAIN RESULTS:  In the pre-exposure scenario, 66% of 190 participants were willing to get vaccinated against smallpox. In contrast, 84% of 200 participants were willing to get vaccinated in the post-exposure scenario ( P  = .0001). African Americans were less willing than whites to get vaccinated in the pre-exposure scenario (54% vs 77%; P  = .004), but not in the post-exposure scenario (84% vs 88%; P  = .56). In multivariate analyses, overall willingness to undergo vaccination was associated with vaccination strategy (odds ratio, 3.29; 95% confidence interval, 1.8 to 6.1).
CONCLUSIONS:  Racial disparity in willingness to get vaccinated varies by the characteristics of the vaccination program. Overall willingness was highest in the context of a post-exposure scenario. These results highlight the importance of considering social issues when constructing bioterror attack response plans that adequately address the needs of all of society's members.     

Isoproterenol reduces ischemia-reperfusion lung injury despite beta-blockade

BACKGROUND: If lungs could be retrieved from non-heart-beating donors (NHBDs), the shortage of lungs for transplantation could be alleviated. The use of lungs from NHBDs is associated with a mandatory warm ischemic interval, which results in ischemia-reperfusion injury upon reperfusion. In an earlier study, rat lungs retrieved 2-h postmortem from NHBDs had reduced capillary leak measured by filtration coefficient (Kfc) when reperfused with isoproterenol (iso), associated with an increase in lung tissue levels of cyclic AMP (cAMP). The objective was to determine if this decrease in Kfc was because of beta-stimulation, or would persist despite beta-blockade. MATERIALS AND METHODS: Donor rats were treated intraperitoneally with beta-blockade (propranolol or pindolol) or carrier, sacrificed, and lungs were retrieved immediately or 2 h postmortem. The lungs were reperfused with or without iso and the beta-blockers in the reperfusate. Outcome measures were Kfc, wet:dry weight ratio (W/D), lung levels of adenine nucleotides and cAMP. RESULTS: Lungs retrieved immediately after death had normal Kfc and W/D. After 2 h of ischemia, Kfc and W/D were markedly elevated in controls (no drug) and lungs reperfused with beta-blockers alone. Isoproterenol-reperfusion decreased Kfc and W/D significantly (P < 0.01) even in the presence of beta-blockade. Lung cAMP levels were increased only with iso in the absence of beta-blockade. CONCLUSIONS: The attenuation of ischemia-reperfusion injury because of iso occurs even in the presence of beta-blockade, and may not be a result of beta-stimulated increased cAMP.     

Cassava cyanogens and fish mercury are high but safely consumed in the diet of native Amazonians

The two most important staple foods (cassava and fish) in the diet of native Amazonians contain neurotoxins (linamarin and monomethyl mercury, MMHg). These same neurotoxins are public health issues in other parts of the world. Factors such as chemistry, environment, and human ecology determine the endemism of neuropathies caused by consumption of cassava (Manihot esculenta Crantz) and fish. Linamarin is a natural component of cassava tubers that can be destroyed before consumption by proper processing. Furthermore, small amounts of the toxin absorbed by people consuming cassava can be effectively metabolized if the diet contains adequate protein-containing sulfur amino acids. Naturally occurring Hg in the waters of the Amazonian rain forest is methylated to MMHg by microorganisms and bioconcentrated in the aquatic food chain. There is no effective method for MMHg removal from fish. Despite high concentrations of naturally occurring neurotoxins in cassava (linamarin) and fish (MMHg), daily consumption of these foods in large amounts over the course of a lifetime poses no health hazards for Amazonians.     

Detection of human papillomaviruses and other agents causing sexually transmitted diseases with molecular diagnosis methods

Causative agents of sexually transmitted diseases (STD) are different types of bacteria, viruses, fungi and protozoa. The last two decades of the twentieth century were marked with a sudden rise in the number of cases of STDs. Human immunodeficiency virus (HIV), which emerged in the 1980s, is the most prominent STD agent because of its fast spread and severity of the disease it causes, acquired immunodeficiency syndrome (AIDS). Beside HIV, human papillomaviruses (HPVs), herpes simplex viruses (HSVs) and Chlamydia trachomatis are nowadays among most health-threatening STD pathogens. In order to stop the spread of infection, apart from education about precautions, early detection of the disease is essential. Although most STD pathogens can be detected by classical methods of cultivation, biochemical and/or serologic methods, molecular diagnosis of infectious diseases has largely simplified and accelerated their detection. For instance, HPVs that cause benign and malignant tumors of genital skin and mucosa cannot be routinely detected on cell culture, whereas serologic analysis is not sensitive and informative enough. Moreover, cytologic (Pap smear) and histologic analyses can indicate changes associated with HPV infection, but neither of these methods can prove the presence of HPV. That is why the molecular methods are essential to demonstrate the presence of the infection and, even more important, to determine the type of the virus, which is associated either with low-grade or high-grade genital lesions. There are numerous methods based on hybridization with DNA or RNA probes, some of them are suitable for detecting wide range of types and screening of large collection of samples. However, the most sensitive and informative methods are based on polymerase chain reaction (PCR), and they have the advantage of being able to determine the type of the virus and distinguishing between multiple infections. Herein, we present when and why molecular analysis is useful and necessary for the detection of STD agents.     

Mercury Biomagnification in a Tropical Black Water,Rio Negro,Brazil

The population living along the riverbanks of the Amazon basin depends heavily on fish for nutritional support. Mono-methyl-mercury (MMHg) concentrates in fish, which can contaminate humans, the risk depending not only on fish MMHg concentration but also on the amount of fish consumed. We sampled nine locations of the Rio Negro basin, differing in water pH, Hg concentrations, and dissolved organic carbon (DOC), and determined total Hg from 951 fish samples of species representative of the food web: herbivorous, detritivorous, omnivorous, and piscivorous. Mercury concentrations varied widely in all species but showed a trend that depended on fish feeding strategies. The highest mean concentration was found in the piscivorous species (688.90 ng/g^–1), followed by omnivorous (190.30 ng/g^–1), detritivorous (136.04 ng/g^–1), and herbivorous (70.39 ng/g^–1). Fish Hg concentrations exceeding current safe limits (500 ng/g^–1) for human consumption were found mainly in the piscivorous species (60%). Significant positive correlation between fish weight and Hg concentration was seen for the piscivorous Serrasalmus spp. (n = 326; r = 0.3977; p < 0.0001), Cichla spp. (n = 125; r = 0.4600; p < 0.0001), and Pimelodus spp. (n = 12; r = 0.8299; p = 0.0008), known locally as Piranha, Tucunaré, and Mandi, respectively. However, a negative correlation was seen for nonpiscivorous Potamorhina latior (n = 30; r –0.3763; p = 0.0404) and Leporinus spp. (n = 44; r = –3987; p = 0.0073), known as Branquinha (detritivorous) and Aracu (omnivorous). Fish-Hg concentrations in the acidic waters (pH range, 4.09–6.31) of the Rio Negro habitat, with its wide gradient of Hg concentrations (3.4–11.9 g/L^–1) and DOC (1.85–15.3 mg/L^–1)—but no history of gold mining activity—are comparable to other Amazonian rivers. Opportunity fish catches in the Rio Negro habitat show high muscle-Hg derived from natural sources, but no systematic association with site-dependent geochemistry.