A longitudinal study of the genetics of personality

A longitudinal twin study was conducted to determine whether personality traits with significant heritability in adolescence remain so in adulthood. A subsample of a group of twins who had been administered in Minnesota Multiphasic Personality Inventory and the California Psychological Inventory in adolescence was readministered the same two inventories 12 years later. The subsample was found to be representative of the sample from which it was drawn. Different patterns of significantly heritability were found for the two ages studied: Several personality traits demonstrated evidence of significant heritability in either adolescence or adulthood, while others demonstrated evidence of significant heritability at both ages. In addition, genetic influences on the change from adolescence to adulthood were found for several personality traits. The results raise important questions for the interpretation of twin research and the understanding of genetic influences on personality development.     

Drinking water and cancer mortality in Louisiana

Multivariant regression analysis indicates a statistically significant relation between cancer mortality rates in Louisiana and drinking water obtained from the Missippi River. This is true for total cancer, cancer of the urinary organs, and cancer of the gastrointestinal tract.     

Personality genetics

Although 30-60% of the variance in many personality traits is inherited, until recently little was known about the responsible genes. Preliminary studies of family history in bipolar disorder and of X-linkage of personality traits in color-blindness suggested a "quantitative trait locus" (QTL) approach to the genetics of normal personality. In methodically similar but independent studies of 124 Israeli and 315 American normal volunteers we showed an association between the dopamine D4 receptor gene (D4DR) and the personality trait of novelty seeking. In the Israeli sample we also found an interaction between the D4DR gene and the serotonin 2C receptor gene (5-HT2C) with a marked effect on the trait of reward dependence. Further investigation of genes for personality traits may suggest links between normal personality and psychiatric illness.     

Endothelial dysfunction in peripheral arterial occlusive disease: from basic research to clinical use

By checking the card indexes of seven out of twelve Social Insurance Offices covering 66% of the total wage-earning population in the city of G?teborg the patients recorded for 90 days of continuous sick-listing were classified into four diagnostic categories according to the doctor's certificate: "non-specific pain" and "specific pain" of the musculoskeletal system, "other pain" and "non-pain" diagnoses. The overall yearly incidence of 90 days' sick-listing averaged 5.4%. A significant correlation was found between the incidence of 90 days' sick-listing due to "non-pain" and musculoskeletal pain diagnoses and the proportion of demographic characteristics of the areas. The hypothesis of presuming the highest association between non-specific pain diagnoses and demographic factors was rejected.     

Pathogenesis, diagnosis, and management of trichomoniasis in cattle

Trichomoniasis is a disease of the pregnancy, but apparently not of either the cow or the bull, except in the case of postcoital pyometra. Its self-limiting nature in the cow and chronic nature in the bull mean that a positive diagnosis for the herd can more easily be obtained from bulls than from cows. Incubation of preputial scrapings or washings (or pyometritic fluid, if available) in a selective growth medium such as the InPouch system is the diagnostic method of choice. The diagnosis is based on identification of the morphology and characteristic rolling motility of the trichomonad. "High tech" molecular approaches may eventually offer greater diagnostic sensitivity than can culture methods, but currently they are no more accurate. In addition, serologic screening of the female herd (but interestingly, not the bulls) may become possible and may allow the practitioner to at least determine whether exposure has occurred in an unvaccinated herd. Control in an infected herd involves no pharmacologic treatment but rather culling of infected bulls, retention of younger, culture-negative bulls, and segregation of the female herd by reproductive status.     

Comparison of secretory responses as measured by membrane capacitance and by amperometry

We have compared capacitance and amperometric measurements in bovine chromaffin cells when secretion was elicited by flash photolysis of caged-calcium or step depolarizations. Total amperometric charge depended linearly on the amount of capacitance increase in both types of experiments. Furthermore, the properties of resolvable amperometric spikes after flashes were comparable to those observed after depolarizations, and their timing was compatible with the rate of capacitance increase. For a more detailed comparison, we used Monte Carlo simulations of multiple amperometric events occurring randomly over the surface of a sphere and summing together, to generate a reference amperometric signal for a given measured capacitance increase. Even after correction for endocytotic processes, the time courses of the integrated experimental records lagged behind the integrated Monte Carlo records by approximately 50 ms in flash and depolarization experiments. This delay was larger by approximately 40 ms than what can be expected from the "pre-foot delay" or the foot duration. Possible sources for the remaining delay could be diffusional barriers like the patch-pipette and the chamber bottom, which are not taken into account in the model. We also applied a novel type of fluctuation analysis to estimate the relative quantum size of an amperometric event. On average the estimates from experimental amperometric traces, in both flash and depolarization experiments, were 3-5 times smaller than estimates from simulated ones. This discrepancy can be due to contributions to the amperometric current from small vesicles, preferred release from cellular regions orientated toward the chamber bottom, or abundance of "foot-only" events. In conclusion, amperometric signals in flash and depolarization experiments displayed similar delayed average time courses and a lower estimate for the relative quantum size compared to the modeled amperometric signals. However, individual amperometric spikes were in agreement with expectations derived from capacitance signals.     

Simultaneously identifying S-phase labelled cells and immunogold-labelling of vinculin in focal adhesions

A new combination of autoradiography and immunolabelling techniques is presented that allows the simultaneous identification of both S‐phase cells and their focal adhesions using scanning electron microscopy. The technique allows both labels to be discerned visually by their unique shapes and location within and on the cell. S‐phase cells were radio‐labelled with a pulse of tritiated thymidine, selectively incorporated into synthesizing DNA. The cells were then immunogold‐labelled for the focal adhesion protein, vinculin, prepared for autoradiography, and embedded in resin. The resin was then polymerized before removing the substrate, to expose the embedded cell undersurface. Electron‐energy ‘sectioning’ of the sample by varying the accelerating voltage of the electron beam allowed separate S‐phase cell identification in one electron‐energy ‘section’ and visualization of immunogold label in another ‘section’, within the same cell. As a result of applying this technique it was possible to positively identify S‐phase cells and immunogold‐labelled focal adhesions on the same cell simultaneously, which could be used to quantify focal adhesion sites on different substrates.