Shared aetiology of risky sexual behaviour and adolescent misconduct: genetic and environmental influences

Risky sexual behaviour (RSB) is a major risk factor for serious diseases as well as unplanned pregnancy. It is not known if RSB has a genetic basis or if it is only influenced by social and cultural conditions. Adolescent conduct disorder has previously been linked to RSB and has been found to be influenced by both genetic and environmental factors. In this study, we look at normal variation in a broad measure of RSB and in retrospectively reported adolescent misconduct in a large community sample of twins ( n  = 4904) to partition the variance and covariance between the traits into genetic and environmental components. We found that RSB is influenced to the same extent by genes, shared environment and unshared environment. Adolescent misconduct is moderately influenced by genetic factors and only modestly by shared environmental factors. Moreover, RSB is associated with adolescent misconduct ( r  = 0.5), primarily because of genetic correlation between the variables. The implications of our findings as well as possible sex differences are discussed.     

V.A.C. instillation: in vitro model. Part 2.

The behavior of a liquid in foam in the course of the V.A.C. instillation was investigated in an in vitro model by visualization using an aqueous color solution and by a quantitative determination of changing concentration of Ringerlactate solution.     

A Photochemical Mechanism for Homochirogenesis. Part 2

A theoretical investigation of the photochemistry of racemic compounds with circularly polarized light was undertaken. The exact solutions of the differential equations by numerical integration to the approximate solutions used in an earlier article were compared. The exact solutions showed that sequential reactions yield enhanced optical activities in the products. For irreversible reactions, all enantiomeric excesses are lost if the reactions are carried to completion, but appreciable resolution occurs in many cases for partial conversion. For reversible reactions, significant enantiomeric excesses are found at the photostationary state. Chirality 25:16‐21, 2013. © 2012 Wiley Periodicals, Inc.     

Melatonin and childbearing: Part 2. Postimplantation period

In this part of the review, we have tried to consider the dependence of the pineal hormone melatonin in human blood serum. It was established that one of the main functions of melatonin is the synchronization of all organs and the regulation of seasonal and diurnal rhythms of their physiological activity. It is confirmed that pregnancy and childbirth directly depend on the rhythm and level of melatonin secretion in the body. It was also found that melatonin maintains the appropriate proliferative level and immune status of the fetus. Disturbances in the melatonin secretion rhythm in children lead to the development of mental (stress and depression) and physiological (preeclampsia, eclampsia, fetal hypoxia, and miscarriages) pathologies. A drastic decrease in the melatonin concentration initiates the childbirth process. Therefore, the creation of conditions for maintaining a sufficient level of melatonin is required to ensure the birth of healthy offspring.     

A student-centred,problem-based curriculum: 5 years' experience.

In 1987, the University of Sherbrooke''s school of medicine implemented a student-centred, problem-based learning (PBL) curriculum. The experience of the first 5 years is reviewed; program goals, the schedule of learning activities, the instructional format and assessment of student learning are described. The new program is more demanding of teachers and requires better faculty training in pedagogy. No new financial resources have been available. The preclinical reform has led to revision of the clerkship, where sessions on clinical reasoning are now based on the PBL philosophy. Student reactions to the program are reported. The Sherbrooke experience has demonstrated that it is both possible and feasible to shift from a traditional to a problem-based curriculum.     

Determination of ochratoxin A in liquorice products using HPLC-based analytical methods. Part II: harmonised method and method validation study

On the basis of the outcome of an European proficiency test series conducted on behalf of the CAOBISCO (Association of the Chocolate, Biscuit and Confectionery Industries of the EU) expert group on ochratoxin A, a new harmonised method was developed for the analysis of ochratoxin A in liquorice extracts. This method works without the use of halogenated solvents because, as the proficiency test showed, an aqueous extraction solution can be used instead of, for example, chloroform, whose use is restricted in the EU. The main objective of this method validation study was to check the performance of this harmonised method. To carry out the method validation study, a set of three different test samples (one liquorice powder and two liquorice pastes) and a liquorice powder sample with an indicated range of ochratoxin A (a so-called sunshine sample) was distributed to 21 laboratories in ten countries throughout Europe and to one laboratory in the USA. The study was evaluated according to internationally recognised guidelines. In terms of its repeatability and reproducibility for determining ochratoxin A in liquorice extracts with a relative standard deviation for repeatability (RSD_r) of between 6.68 and 19.95 and a relative standard deviation for reproducibility (RSD_R) of between 17.39 and 29.08 the performance of the harmonised method was found to be in the accepted range of the EU directive for the analysis of mycotoxins in several foodstuffs.     

The evolution of sexual reproduction as a repair mechanism. Part I. A model for self-repair and its biological implications

Summary The theory is presented that the sexual process is a repair mechanism which maintains redundancy within the sub-structure of hierarchical, self-reproducing organisms. In order to keep the problems within mathematically tractable limits (see Part II), a simple model is introduced: a wheel with 6 spokes, 3 of them vital and 3 redundant, symbolizes the individual (cell or organism). Random accidents destroy spokes; the wheels replicate at regular cycles and engage periodically in pairing and repair phases during which missing spokes are copy-reproduced along the intact spokes of the partner wheel.The hierarchical structure of such a system is analysed and an autonomous unit is defined: this is the unit of minimal hierarchical complexity which is capable of perpetuating autonomously all higher and all lower levels of the hierarchy; this is the central unit of selection.Four basic, physical parameters are isolated which determine the essential features of any eucaryotic life cycle: 1. The number of levels of the hierarchy (unicellular, multicellular, colonial, etc.); 2. the relation between the phases of replication (asexual generations) and repair (sexual generations); 3. the duration of potential repair (haplo- diplo-phases); 4. the position of the sexual partners within the hierarchy (selfing, monecy, dioecy, reproductive individuals within colonies, etc.).The evaluation of fitness components is considered in relation to trends of reproductive patterns in evolution.     

Student perceptions of mistreatment and harassment during medical school. A survey of ten United States schools.

Senior students at 10 medical schools in the United States responded to a questionnaire that asked how often, if ever, they perceived themselves being mistreated or harassed during the course of their medical education. Results show that perceived mistreatment most often took the form of public humiliation (86.7%), although someone else taking credit for one''s work (53.5%), being threatened with unfair grades (34.8%), and threatened with physical harm (26.4%) were also reported. Students also reported high rates of sexual harassment (55%) and pervasive negative comments about entering a career in medicine (91%). Residents and attending physicians were cited most frequently as sources of this mistreatment. With the exception of more reports of sexual harassment from women students, perceived mistreatment did not differ significantly across variables such as age, sex, religion, marital status, or having a physician parent. Scores from the 10 schools also did not vary significantly, although the presence of a larger percentage of women in the class appeared to increase overall reports of mistreatment from both sexes.     

Cryopreservation of articular cartilage. Part 3: The liquidus-tracking method

Although it is relatively straightforward to cryopreserve living isolated chondrocytes, at the present time there is no satisfactory method to preserve surgical grafts between the time of procurement or manufacture and actual use. In earlier papers we have established that the cryoprotectants dimethyl sulphoxide or propylene glycol do penetrate into this tissue very rapidly. Chondrocytes are not unusually susceptible to osmotic stress; in fact they appear to be particularly resistant. It appears that damage is associated with the formation of ice per se, even at cooling rates that are optimal for the cryopreservation of isolated chondrocytes. We then showed that current methods of cartilage cryopreservation involve the nucleation and growth of ice crystals within the chondrons rather than ice being restricted to the surrounding acellular matrix. This finding established the need to avoid the crystallization of ice—in other words, vitrification. Song and his colleagues have published a vitrification method that is based on the use of one of Fahy’s vitrification formulations. We confirmed the effectiveness of this method but found it to be very dependent on ultra rapid warming. However, we were able to develop a ‘liquidus-tracking’ method that completely avoids the crystallization of ice and does not require rapid warming. The ability of cartilage preserved in this way to incorporate sulphate into newly synthesized glycosaminoglycans (GAGs) approached 70% of that of fresh control cartilage. In this method the rates of cooling and warming can be very low, which is essential for any method that is to be used in Tissue Banks to process the bulky grafts that are required by orthopaedic surgeons. Work is continuing to refine this method for Tissue Bank use.     

Cryopreservation of articular cartilage. Part 3: the liquidus-tracking method

Although it is relatively straightforward to cryopreserve living isolated chondrocytes, at the present time there is no satisfactory method to preserve surgical grafts between the time of procurement or manufacture and actual use. In earlier papers we have established that the cryoprotectants dimethyl sulphoxide or propylene glycol do penetrate into this tissue very rapidly. Chondrocytes are not unusually susceptible to osmotic stress; in fact they appear to be particularly resistant. It appears that damage is associated with the formation of ice per se, even at cooling rates that are optimal for the cryopreservation of isolated chondrocytes. We then showed that current methods of cartilage cryopreservation involve the nucleation and growth of ice crystals within the chondrons rather than ice being restricted to the surrounding acellular matrix. This finding established the need to avoid the crystallization of ice—in other words, vitrification. Song and his colleagues have published a vitrification method that is based on the use of one of Fahy’s vitrification formulations. We confirmed the effectiveness of this method but found it to be very dependent on ultra rapid warming. However, we were able to develop a ‘liquidus-tracking’ method that completely avoids the crystallization of ice and does not require rapid warming. The ability of cartilage preserved in this way to incorporate sulphate into newly synthesized glycosaminoglycans (GAGs) approached 70% of that of fresh control cartilage. In this method the rates of cooling and warming can be very low, which is essential for any method that is to be used in Tissue Banks to process the bulky grafts that are required by orthopaedic surgeons. Work is continuing to refine this method for Tissue Bank use.