Why does starvation make bones fat?

Body fat, or adipose tissue, is a crucial energetic buffer against starvation in humans and other mammals, and reserves of white adipose tissue (WAT) rise and fall in parallel with food intake. Much less is known about the function of bone marrow adipose tissue (BMAT), which are fat cells found in bone marrow. BMAT mass actually increases during starvation, even as other fat depots are being mobilized for energy. This review considers several possible reasons for this poorly understood phenomenon. Is BMAT a passive filler that occupies spaces left by dying bone cells, a pathological consequence of suppressed bone formation, or potentially an adaptation for surviving starvation? These possibilities are evaluated in terms of the effects of starvation on the body, particularly the skeleton, and the mechanisms involved in storing and metabolizing BMAT during negative energy balance. Am. J. Hum. Biol., 2011. © 2011 Wiley‐Liss, Inc.     

Why study human limb malformations?

Congenital limb malformations occur in 1 in 500 to 1 in 1000 human live births and include both gross reduction defects and more subtle alterations in the number, length and anatomy of the digits. The major causes of limb malformations are abnormal genetic programming and intra-uterine disruption to development. The identification of causative gene mutations is important for genetic counselling and also provides insights into the mechanisms controlling limb development. This article illustrates some of the lessons learnt from the study of human limb malformation, organized into seven categories. These are: (1) identification of novel genes, (2) allelic mutation series, (3) pleiotropy, (4) qualitative or (5) quantitative differences between mouse and human development, (6) physical and teratogenic disruption, and (7) unusual biological phenomena.     

Does disorganised attachment lead to auditory hallucinations via dissociation? An experimental study with an analogue sample

Objectives

Auditory hallucinations (such as hearing voices) are common in clinical and non-clinical populations. Many people who hear voices also report early adversity and have an insecure attachment style. Current cognitive models suggest that dissociation mediates an association between disorganised attachment and auditory hallucinations, but this has not been tested experimentally.

Design

We recruited a non-clinical analogue sample highly predisposed to auditory hallucinations and utilised an experimental design to examine the impact of disorganised attachment imagery on hallucinatory experiences, and whether dissociation mediates an expected association.

Methods

Participants completed self-report measures of state auditory hallucinations and dissociation before and after random allocation to secure or disorganised attachment conditions.

Results

Attachment imagery did not affect auditory hallucinations. Both secure and disorganised attachment conditions increased state dissociation. Secure attachment imagery reduced paranoia, but state dissociation did not mediate this effect. An exploratory analysis found that trait dissociation fully accounted for the association between trait-disorganised attachment and hallucinatory experience while controlling for paranoia.

Conclusions

Secure attachment imagery reduces paranoia but not auditory hallucinations and the impact on paranoia is not mediated by dissociation. Secure attachment imagery may be useful in reducing fears and distress associated with voices, rather than the frequency or severity of hallucinations. Disorganised attachment may increase hallucinatory experiences for people vulnerable to dissociation. Trait dissociation should be assessed in clinical settings and addressed where indicated as a means of targeting vulnerability to distressing voices.     

How does typicality of category members affect the deductive reasoning? An ERP study

The typicality effect describes a phenomenon whereby a typical item is easier to be judged as a member of a category than are atypical items. This effect has been intensively studied in the context of category verification tasks. The present study further investigated the typicality effect using our newly developed category-based deductive reasoning task. Subjects were required to judge whether an incoming stimulus had the properties described in the premise presented before. The stimuli were either typical or atypical members of four target semantic categories or were non-target stimuli. According to the ERP results, three phases were needed to determine whether the object has the property associated with the category in the premise. First, significant amplitude differences were seen between typical and atypical items at N1, which suggested that attention processing was influenced by the expectation in this up-to-down (deductive) process. The premise automatically induced the expectation of the prototype of one concept, i.e. the expectation for the prototype of birds was induced when the premise was “Birds possess the property C”. Typical items (e.g., sparrow) were more similar to the prototype; hence, they were easier to be matched with the prototype induced by the premise than were atypical items (e.g., ostrich). Additionally, there was a dissociation between typical and atypical items at P2, which suggested that the participants’ early detection of an item’s category membership was influenced by the typicality. Thirdly, N400 effect is related to the process of semantic processes and determining whether the object has the property associated with the category in the premise. N400 mean amplitudes during the 300–500 ms epoch were significantly greater for non-target members than for target members, while words of lower typicality (atypical) evoked greater N400 amplitudes during the 350–450 ms epoch than did words of higher typicality (typical).     

Why does schizophrenia develop at late adolescence?

Schizophrenia is one of the most researched, yet still one of the least understood, of the mental disorders. One key area that remains comparatively neglected is the fact that schizophrenia typically develops at late adolescence. In common with people with psychotic disorders, around 25% of normal teenagers also report finding adolescence very distressing, and a substantial empirical literature shows that certain characteristics typical of adolescence such as conflicted family relationships, grandiosity, egocentrism, and magical ideation bear a distinct resemblance to phenomena seen in psychotic disorders. Indeed, such phenomena, as might be judged prodromal or symptomatic in first-onset schizophrenia, have been shown to be remarkably common in normal adolescents, generally in about 50% of samples. Furthermore, prodromal-like signs in normal adolescents appear to be functionally linked to psychological development. For most adolescents, such phenomena pass with successful psychological development. It is proposed that psychosis in late adolescence is a consequence of severe disruption in this normally difficult psychological maturational process in vulnerable individuals, and explanations are offered as to why and how this comes about. It is suggested that problems either in reaching psychological maturity with regard to parents or in bonding to peers or both, may lead to crucial self-construction difficulties, and that psychosis emerges out of such "blocked adolescence." This approach proposes therapeutic interventions that enable professional services to side with both parents and clients simultaneously, and is normalizing and stigma-free.     

Why not just Google it? An assessment of information literacy skills in a biomedical science curriculum

Background  

Few issues in higher education are as fundamental as the ability to search for, evaluate, and synthesize information. The need to develop information literacy, the process of finding, retrieving, organizing, and evaluating the ever-expanding collection of online information, has precipitated the need for training in skill-based competencies in higher education, as well as medical and dental education.     

Osteoarthritis of the knee: Why does exercise work? A qualitative study of the literature

The effectiveness of exercise to reduce pain and improve functioning in osteoarthritis of the knee (OAk) is well substantiated. Underlying mechanisms are still under debate and better understanding of the pathways involved may contribute to more targeted treatment strategies. The present qualitative analysis of the literature aims to provide an overview of theoretical models that are put forward to explain the beneficial treatment effects of exercise in OAk. An inductive qualitative approach, based on the ‘grounded theory’ of Glaser and Straus, was used. Twenty-two studies emphasizing on exercise therapy for OAk, collected from three Cochrane reviews and nine guidelines of the Physiotherapy Evidence Database (PEDRO) published between 2000 and 2012, were included. The introduction and discussion parts of these papers were screened for explanations of exercise-induced benefits in OAk patients. Seventy-three key points were identified which were subdivided into 16 core theoretical concepts. Finally, 5 categories were formed: neuromuscular, peri-articular, intra-articular, psychosocial components, and general fitness and health. We referred to scientific evidence that was used in the included studies to describe and categorize the concepts. Future research on exercise in OAk should allow distinguishing the contribution of different potential pathways to the treatment effects.     

Why does age of onset predict clinical severity in schizophrenia? A multiplex extended pedigree study

Schizophrenia has substantial variation in symptom severity, course of illness, and overall functioning. Earlier age of onset (AOO) is consistently associated with negative outcomes and yet the causes of this association are still unknown. We used a multiplex, extended pedigree design (total N = 771; 636 relatives from 43 multigenerational families with at least 2 relatives diagnosed with schizophrenia and 135 matched controls) to examine among the schizophrenia relatives (N = 103) the relationship between AOO and negative and positive symptom severity, cognition, and community functioning. Most importantly, we assessed whether there are shared genetic effects between AOO and negative symptoms, positive symptoms, cognition, and community functioning. As expected, earlier AOO was significantly correlated with increased severity of negative and positive symptoms and poorer cognition and community functioning among schizophrenia patients. Notably, the genetic correlation between AOO of schizophrenia and negative symptoms was significant (R_g = ?1.00, p = .007). Although the genetic correlations between AOO and positive symptoms, cognition, and community functioning were estimated at maximum and in the predicted direction, they were not statistically significant. AOO of schizophrenia itself was modestly heritable, although not significant and negative symptoms, positive symptoms, and cognition were all strongly and significantly heritable. In sum, we replicated prior findings indicating that earlier AOO is associated with increased symptom severity and extended the literature by detecting shared genetic effects between AOO and negative symptoms, suggestive of pleiotropy.