Longitudinal analysis of cognitive performances and structural brain changes in late-life bipolar disorder.

OBJECTIVES: Cross-sectional studies in bipolar disorder (BD) suggested the presence of cognitive deficits and subtle magnetic resonance imaging (MRI) changes in limbic areas that may persist at euthymic stages. Whether or not cognitive and MRI changes represent stable attributes of BD or evolve with time is still matter of debate. To address this issue, we performed a 2-year longitudinal study including detailed neuropsychological and magnetic resonance imaging (MRI) analyses of 15 euthymic older BD patients and 15 controls. METHODS: Neuropsychological evaluation concerned working memory, episodic memory, processing speed, and executive functions. MRI analyses included voxel-based morphometry (VBM) analysis of gray matter including region of interest (ROI) analysis and tract-based spatial statistics (TBSS) analysis of white matter of diffusion tensor imaging derived fractional anisotropy (FA). RESULTS: BD patients displayed significantly lower performances in processing speed and episodic memory but not in working memory and executive functions compared to controls. However, BD patients did not differ from controls in the mean trajectory of cognitive changes during the 2 years follow-up. In the same line, longitudinal gray matter (VBM, ROI) and white matter (TBSS FA) changes did not differ between BD patients and controls. CONCLUSION: The lack of distinction between BD patients and controls in respect to the 2-year changes in cognition and MRI findings supports the notion that this disorder does not have a significant adverse impact on cognitive and brain aging. From this point of view, the present results convey a message of hope for patients suffering from BD.

Extraordinary intraspecific diversity in oyster sperm bindin.

In free-spawning invertebrates sperm-egg incompatibility is a barrier to mating between species, and divergence of gamete recognition proteins (GRPs) can result in reproductive isolation. Of interest are processes that create reproductive protein diversity within species, because intraspecific variants are potentially involved in mate choice and early speciation. Sperm acrosomes of the Pacific oyster Crassostrea gigas contain the protein bindin that bonds sperm to egg during fertilization. Oyster bindin is a single-copy gene encoding a diversity of protein variants. Oyster bindins have a conserved N-terminal region followed by one to five tandem fucose-binding lectin (F-lectin) domains. These repeats have diversified by positive selection at eight sites clustered on the F-lectin's fucose binding face. Additional bindin variants result from recombination in an intron in each F-lectin repeat. Males also express alternatively spliced bindin cDNAs with one to five repeats, but typically translate only one or two isoforms into protein. Thus, positive selection, alternative splicing, and recombination can create thousands of bindin variants within C. gigas. Models of sexual conflict predict high male diversity when females are diverse and sexual conflict is strong. The amount of intraspecific polymorphism in male GRPs may be a consequence of the relative efficiency of local (molecular recognition) and global (electrical, cortical, and physical) polyspermy blocks that operate during fertilization.

Cytasters from sea urchin eggs parthenogenetically activated by procaine.

A method is presented for the isolation of cytasters from unfertilized sea urchin eggs parthenogenetically activated by procaine. These cytasters do not appear to contain centrioles. The microtubules seem to grow out from the condensed chromosomes. The chromosomes have an unusual morphology.

Identification of sea urchin sperm adenylate cyclase.

Calmodulin (CaM) affinity chromatography of a detergent extract of sea urchin sperm yielded approximately 20 major proteins. One of these proteins, of Mr 190,000, was purified and used to immunize rabbits. After absorption with living sperm, the serum reacted monospecifically on one- and two-dimensional Western immunoblots with the Mr 190,000 protein. The anti-190-kD serum inhibited 94% of the adenylate cyclase (AC) activity of the CaM eluate. An immunoaffinity column removed 95% of the AC activity, and the purified (but inactive) Mr 190,000 protein was eluted from the column. The antiserum also inhibited 23% of the activity of bovine brain CaM-sensitive AC and 90% of the activity of horse sperm CaM-sensitive AC. These data support the hypothesis that the Mr 190,000 protein is sea urchin sperm AC. Although this AC bound to CaM, it was not possible to demonstrate directly a Ca2+ or CaM sensitivity. However, two CaM antagonists, calmidazolium and chlorpromazine, both inhibited AC activity, and the inhibition was released by added CaM, suggesting the possibility of regulation of this AC by CaM. Indirect immunofluorescence showed the Mr 190,000 protein to be highly concentrated on only the proximal half of the sea urchin sperm flagellum. This asymmetric localization of AC may be important to its function in flagellar motility. This is the first report of the identification of an AC from animal spermatozoa.

Isolation and characterization of sea urchin egg cortical granules.

A method has been developed to isolate cortical granules (CG) free in suspension. It involves the mechanical disruption of the CG from CG lawns (CGL; Dev. Biol. 43:62-74, 1975) and concentration of the CG by low speed centrifugation. The isolated CG are intact and are a relatively pure population as judged by electron microscopy. Granule integrity is confirmed by the fact that isolated intact CG are radioiodinated to only 0.05% of the specific activity of hypotonically lysed CG. Purity of the CG preparation is assessed by the enrichment (four- to sevenfold) of CG marker enzymes and the absence or low activity of plasma membrane, mitochondrial, cytoplasmic, and yolk platelet marker enzyme activities. CG isolated from 125I-surface-labeled eggs have a very low specific radioactivity, demonstrating that CG contamination by the plasma membrane-vitelline layer (PM-VL) is minimal. CG yield is approximately 1% of the starting egg protein. The CG isolation method is simple and rapid, 4 mg of CG protein being obtained in 1 h. Isolated CG and PM-VL display distinct electrophoretic patterns on SDS gels. Actin is localized to the PM-VL, and all bands present in the CGL are accounted for in the CG and PM-VL. Calmodulin is associated with the CGL, CG, and PM-VL fractions, but is not specifically enriched in these fractions as compared with whole egg homogenates. This method of isolating intact CG from unfertilized sea urchin eggs may be useful for exploring the mechanism of Ca2+-mediated CG exocytosis.

Phosphorylation of membrane-bound guanylate cyclase of sea urchin spermatozoa.

When Arbacia punctulata spermatozoa are incubated in seawater containing ammonium hydroxide (pH 8.8), the sperm plasma membrane-bound guanylate cyclase is dephosphorylated, its electrophoretic mobility increases (from an apparent molecular mass of 160 to 150 kD), and its enzymatic activity decreases 3.5-fold. Transfer of these cells into ammonium-free seawater (pH 7.4) results in the rephosphorylation of the cyclase, its reconversion to 160 kD, and recovery of the enzymatic activity lost upon dephosphorylation. This is the first direct demonstration that the activity of membrane-bound guanylate cyclase can be regulated by phosphorylation. A plasma membrane preparation is described that specifically supports the in vitro phosphorylation of the guanylate cyclase. This preparation will be useful in more detailed studies on the relationship between phosphorylation state and enzymatic activity of membrane-bound guanylate cyclase.

Monoclonal antibodies to a membrane glycoprotein induce the phosphorylation of histone H1 in sea urchin spermatozoa.

Two groups of mAbs reacting with external domains of a major sea urchin sperm membrane glycoprotein of 210 kD were isolated. Previous studies have shown that group I mAbs inhibit the acrosome reaction induced by egg jelly and also cause large increases in intracellular Ca2+ [( Ca2+]i). Group II mAbs, at comparable levels of cell surface binding, neither inhibit the egg jelly-induced acrosome reaction nor cause increases in [Ca2+]i. In this paper, we investigate the ability of these mAbs to induce the cAMP-dependent phosphorylation of sperm histone H1. Group I mAbs induce H1 phosphorylation to the same level and on the same peptide, as occurs upon treatment of sperm with egg jelly. These mAbs also activate adenylate cyclase to the same extent as egg jelly. Group II mAbs do not induce H1 phosphorylation and are only poor activators of adenylate cyclase. Group I mAbs compete with each other, but not with group II mAbs, for binding to the cell surface. These data indicate that the activation of adenylate cyclase is an initial event in the pathway leading from the binding of mAbs to a specific domain of the 210-kD protein at the cell surface, to the discrete phosphorylation of histone H1 in highly condensed sperm chromatin. The domain on the 210-kD protein recognized by group I mAbs plays a critical role in signal transduction during the early events of fertilization.

The sea urchin sperm receptor for egg jelly is a modular protein with extensive homology to the human polycystic kidney disease protein, PKD1.

During fertilization, the sea urchin sperm acrosome reaction (AR), an ion channel-regulated event, is triggered by glycoproteins in egg jelly (EJ). A 210-kD sperm membrane glycoprotein is the receptor for EJ (REJ). This conclusion is based on the following data: purified REJ binds species specifically to EJ dotted onto nitrocellulose, an mAb to REJ induces the sperm AR, antibody induction is blocked by purified REJ, and purified REJ absorbs the AR-inducing activity of EJ. Overlapping fragments of REJ cDNA were cloned (total length, 5,596 bp). The sequence was confirmed by microsequencing six peptides of mature REJ and by Western blotting with antibody to a synthetic peptide designed from the sequence. Complete deglycosylation of REJ followed by Western blotting yielded a size estimate in agreement with that of the mature amino acid sequence. REJ is modular in design; it contains one EGF module and two C-type lectin carbohydrate-recognition modules. Most importantly, it contains a novel module, herein named the REJ module (700 residues), which shares extensive homology with the human polycystic kidney disease protein (PKD1). Mutations in PKD1 cause autosomal dominant polycystic kidney disease, one of the most frequent genetic disease of humans. The lesion in cellular physiology resulting from mutations in the PKD1 protein remains unknown. The homology between REJ modules of the sea urchin REJ and human PKD1 suggests that PKD1 could be involved in ionic regulation.

A computerized bioskills system for surgical skills training in total knee replacement.

Although all agree that the results of total knee replacement (TKR) are primarily determined by surgical skill, there are few satisfactory alternatives to the 'apprenticeship' model of surgical training. A system capable of evaluating errors of instrument alignment in TKR has been developed and demonstrated. This system also makes it possible quantitatively to assess the source of errors in final component position and limb alignment. This study demonstrates the use of a computer-based system to analyse the surgical skills in TKR through detailed quantitative analysis of the technical accuracy of each step of the procedure. Twelve surgeons implanted a posterior-stabilized TKR in 12 fresh cadavers using the same set of surgical instruments. During each procedure, the position and orientation of the femur, tibia, each surgical instrument, and the trial components were measured with an infrared coordinate measurement system. Through analysis of these data, the sources and relative magnitudes of errors in position and alignment of each instrument were determined, as well as its contribution to the final limb alignment, component positioning and ligament balance. Perfect balancing of the flexion and extension gaps was uncommon (0/15). Under standardized loading, the opening of the joint laterally exceeded the opening medially by an average of approximately 4 mm in both extension (4.1 +/- 2.1 mm) and flexion (3.8 +/- 3.4 mm). In addition, the overall separation of the femur and the tibia was greater in flexion than extension by an average of 4.6 mm. The most significant errors occurred in locating the anterior/posterior position of the entry point in the distal femur (SD = 8.4 mm) and the correct rotational alignment of the tibial tray (SD = 13.2 degrees). On a case-by-case basis, the relative contributions of errors in individual instrument alignments to the final limb alignment and soft tissue balancing were identified. The results indicate that discrete steps in the surgical procedure make the largest contributions to the ultimate alignment and laxity of the prosthetic knee. Utilization of this method of analysis and feedback in orthopaedic training is expected rapidly to enhance surgical skills without the risks of patient exposure.

Evaluation of certain food additives and contaminants.

This report represents the conclusions of a Joint FAO/WHO Expert Committee convened to evaluate the safety of various food additives, including flavouring agents, with a view to recommending acceptable daily intakes (ADIs) and to preparing specifications for identity and purity. The Committee also evaluated the risk posed by two food contaminants, with the aim of advising on risk management options for the purpose of public health protection. The first part of the report contains a general discussion of the principles governing the toxicological evaluation and assessment of intake of food additives (in particular flavouring agents) and contaminants. A summary follows of the Committee's evaluations of technical, toxicological and intake data for certain food additives (acidified sodium chlorite, asparaginase from Aspergillus oryzae expressed in Aspergillus oryzae, carrageenan and processed Eucheuma seaweed, cyclotetraglucose and cyclotetraglucose syrup, isoamylase from Pseudomonas amyloderamosa, magnesium sulfate, phospholipase A1 from Fusarium venenatum expressed in Aspergillus oryzae, sodium iron(III) ethylenediaminetetraacetic acid (EDTA) and steviol glycosides); eight groups of related flavouring agents (linear and branched-chain aliphatic, unsaturated, unconjugated alcohols, aldehydes, acids and related esters; aliphatic acyclic and alicyclic terpenoid tertiary alcohols and structurally related substances; simple aliphatic and aromatic sulfides and thiols; aliphatic acyclic dials, trials and related substances; aliphatic acetals; sulfur-containing heterocyclic compounds; aliphatic and aromatic amines and amides; and aliphatic alicyclic linear alpha, beta -unsaturated di- and trienals and related alcohols, acids and esters); and two food contaminants (aflatoxin and ochratoxin A). Specifications for the following food additives were revised: maltol and ethyl maltol, nisin preparation, pectins, polyvinyl alcohol, and sucrose esters of fatty acids. Specifications for the following flavouring agents were revised: maltol and ethyl maltol, maltyl isobutyrate, 3-acetyl-2,5-dimethylfuran and 2,4,5-trimethyl-delta-oxazoline (Nos 1482, 1506 and 1559), and monomenthyl glutarate (No. 1414), as well as the method of assay for the sodium salts of certain flavouring agents. Annexed to the report are tables summarizing the Committee's recommendations for intakes and toxicological evaluations of the food additives and contaminants considered.

Isolation and characterization of a plasma membrane fraction from sea urchin sperm exhibiting species specific recognition of the egg surface.

A method is described for isolating preparative quantities of plasma membranes from sea urchin sperm. The final membrane fraction is homogeneous by sucrose density sedimentation and is enriched in adenylate cyclase as well as in the four glycoproteins accessible to radioiodination of intact sperm. The electrophoretic profiles of sperm membranes from three sea urchin species are very similar. The membrane preparation consists primarily of sealed vesicles which release carboxyfluorescein when exposed to detergents or distilled water. Ninety-two percent of the 125I-labeled vesicle material binds to wheat germ lectin columns, suggesting a right-side-out orientation. The isolated sperm membrane vesicles exhibit species specific adhesion to the surfaces of sea urchin eggs; this adhesion is blocked by pretreatment of the vesicles with trypsin or egg jelly. This method will be useful for isolating biologically active sperm membrane components involved in sperm-egg recognition during fertilization.

Public health aspects of food irradiation.

In view of the enormous health and economic consequences of foodborne diseases, the World Health Organization (WHO) encourages its Member States to consider all measures to eliminate or reduce foodborne pathogens in food and improve their supplies of safe and nutritious food. With the wholesomeness of irradiated food clearly established by extensive scientific studies, food irradiation has important roles to play in both ensuring food safety and reducing food losses. Food irradiation may be one of the most significant contributions to public health to be made by food science and technology since the introduction of pasteurization. Because the promotion of a safe, nutritious and adequate food supply is an essential component of its primary health care strategy, WHO is concerned that the unwarranted rejection of this process may endanger public health and deprive consumers of the choice of food processed for safety.

Dephosphorylation of sea urchin sperm guanylate cyclase during fertilization.

Exposure of Arbacia punctulata spermatozoa to solubilized egg jelly results in the immediate dephosphorylation (within 3 sec) of an abundant 160,000 dalton (160 kDa) sperm membrane protein, and a simultaneous increase in its electrophoretic mobility to 150 kDa. The sperm phosphoprotein has been identified as guanylate cyclase. Correlated with the mobility shift of the cyclase is a decrease in its enzymatic activity. In this paper we will briefly review the work on the sperm guanylate cyclase, present new data on the role of ion fluxes in the control of its dephosphorylation, and discuss what role the dephosphorylation might play in successful sperm-egg interaction.

Towards internationally acceptable standards for food additives and contaminants based on the use of risk analysis.

Internationally acceptable norms need to incorporate sound science and consistent risk management principles in an open and transparent manner, as set out in the Agreement on the Application of Sanitary and Phytosanitary Measures (the SPS Agreement). The process of risk analysis provides a procedure to reach these goals. The interaction between risk assessors and risk managers is considered vital to this procedure. This paper reports the outcome of a meeting of risk assessors and risk managers on specific aspects of risk analysis and its application to international standard setting for food additives and contaminants. Case studies on aflatoxins and aspartame were used to identify the key steps of the interaction process which ensure scientific justification for risk management decisions. A series of recommendations were proposed in order to enhance the scientific transparency in these critical phases of the standard setting procedure.

Magnetic resonance imaging determinants of intraindividual variability in the elderly: combined analysis of grey and white matter.

Elderly individuals display a rapid age-related increase in intraindividual variability (IIV) of their performances. This phenomenon could reflect subtle changes in frontal lobe integrity. However, structural studies in this field are still missing. To address this issue, we computed an IIV index for a simple reaction time (RT) task and performed magnetic resonance imaging (MRI) including voxel based morphometry (VBM) and the tract based spatial statistics (TBSS) analysis of diffusion tensor imaging (DTI) in 61 adults aged from 22 to 88 years. The age-related IIV increase was associated with decreased fractional anisotropy (FA) as well as increased radial (RD) and mean (MD) diffusion in the main white matter (WM) fiber tracts. In contrast, axial diffusion (AD) and grey matter (GM) densities did not show any significant correlation with IIV. In multivariate models, only FA has an age-independent effect on IIV. These results revealed that WM but not GM changes partly mediated the age-related increase of IIV. They also revealed that the association between WM and IIV could not be only attributed to the damage of frontal lobe circuits but concerned the majority of interhemispheric and intrahemispheric corticocortical connections.

Residues of persistent organic pollutants (POPs) in human milk in Hong Kong.

Data on pesticide body load in the south China region are scarce. Here, we report the concentrations of 24 persistent organic pollutants (POPs), in 10 pools of human milk samples, collected at 2-6weeks postpartum from 238 primiparous women living in Hong Kong and south China, who participated in the 2002-2003 WHO exposure study. Residues were determined by gas chromatography with electron capture detector and confirmed by gas chromatography with mass spectrometry. The mean levels of alpha-HCH (mean 0.6ngg(-1) fat), beta-HCH (940ngg(-1) fat), gamma-HCH (1.8ngg(-1) fat), dieldrin (1.0ngg(-1) fat) and HCB (21.8ngg(-1) fat) were much lower than the 1985 estimates. Mean levels of alpha-HCH, gamma-HCH, dieldrin, cis-heptachlor-epoxide (0.7ngg(-1) fat), sum-chlordane (6.1ngg(-1) fat), trans-nonachlor (12.0ngg(-1) fat), BDE 47 (1.9ngg(-1) fat) and sum PBDE (3.4ngg(-1) fat) were comparable to the international median levels of the 15 other countries participating in the 2002-03 WHO exposure study. Hong Kong had the highest level of beta-HCH, possibly a residual effect of previous high exposures in the 1970s. Body loads of beta-HCH and chlordane were lower among mothers with younger age while mothers born in mainland China had lower levels of beta-HCH, cis-heptachlor-epoxide, oxy-chlordane and trans-nonachlor. Levels of toxaphene, endrin, endosulfan, bromcyclene and nitrofen were not detected in all or almost all of the milk pools. Continuous monitoring of POPs in human milk, especially beta-HCH, is needed for surveillance and interpretation of time trends, and for linkage to strict enforcement of agricultural regulations.

The contribution of aging to the understanding of the dimensionality of executive functions.

It has been reported in the literature that executive functions may be fractioned into updating, shifting, and inhibition. The present study aimed to explore whether these executive sub-components can be identified in a more age-heterogeneous sample and see if they are prone to an age-related decline. We tested the performances of 81 individuals aged from 18 to 88 years old in each executive sub-component, working memory, fluid intelligence and processing speed. Correlation analysis revealed only a slight positive relationship between the two updating measures. A linear decrement with age was observed only for two complex executive tests. Tasks indexing working memory, processing speed and fluid intelligence showed a stronger linear decline with age than executive tasks. In conclusion, our results did not replicate the executive structure known from the literature, and revealed that decrement in executive function is not an unavoidable concomitant of aging but rather concerns specific executive tasks.

Measuring taste impairment in epidemiologic studies: the Beaver Dam Offspring Study.

Taste or gustatory function may play an important role in determining diet and nutritional status and therefore indirectly impact health. Yet there have been few attempts to study the spectrum of taste function and dysfunction in human populations. Epidemiologic studies are needed to understand the impact of taste function and dysfunction on public health, to identify modifiable risk factors, and to develop and test strategies to prevent clinically significant dysfunction. However, measuring taste function in epidemiologic studies is challenging and requires repeatable, efficient methods that can measure change over time. Insights gained from translating laboratory-based methods to a population-based study, the Beaver Dam Offspring Study (BOSS) will be shared. In this study, a generalized labeled magnitude scale (gLMS) method was used to measure taste intensity of filter paper disks saturated with salt, sucrose, citric acid, quinine, or 6-n-propylthiouracil, and a gLMS measure of taste preferences was administered. In addition, a portable, inexpensive camera system to capture digital images of fungiform papillae and a masked grading system to measure the density of fungiform papillae were developed. Adult children of participants in the population-based Epidemiology of Hearing Loss Study in Beaver Dam, Wisconsin, are eligible for this ongoing study. The parents were residents of Beaver Dam and 43-84 years of age in 1987-1988; offspring ranged in age from 21-84 years in 2005-2008. Methods will be described in detail and preliminary results about the distributions of taste function in the BOSS cohort will be presented.

Improving the safety of street-vended food.

An integrated plan of action for improving street food involving health and other regulatory authorities, vendors and consumers should address not only food safety, but also environmental health management, including consideration of inadequate sanitation and waste management, possible environmental pollution, congestion and disturbances to traffic. However, WHO cautions that, in view of their importance in the diets of urban populations, particularly the socially disadvantaged, every effort should be made to preserve the benefits provided by varied, inexpensive and often nutritious street food. Therefore, authorities concerned with street food management must balance efforts aimed at reducing the negative aspects on the environment with the benefits of street food and its important role in the community. Health authorities charged with responsibility for food safety control should match risk management action to the level of assessed risk. The rigorous application of codes and enforcement of regulations more suited to larger and permanent food service establishments is unlikely to be justifiable. Such rigorous application of codes and regulations may result in disappearance of the trade with consequent aggravation of hunger and malnutrition. Moreover, most codes and regulations have not been based on any systematic identification and assessment of health hazards associated with different types of foods and operations as embodied in the HACCP approach which has been recognized by Codex as the most cost-effective means for promoting food safety. WHO encourages the development of regulations that empower vendors to take greater responsibility for the preparation of safe food, and of codes of practice based on the HACCP system.