Assessing the bilateral geometrical differences of the tibia – Are they the same?

Contralateral bones are often used in many medical applications but it is assumed that their bilateral differences are insignificant. Previous studies used a limited number of distance measurements in quantifying the corresponding differences; therefore, little is known about their bilateral 3D surface asymmetries. The aim of the study is to develop a comprehensive method to quantify geometrical asymmetries between the left and right tibia in order to provide first results on whether the contralateral tibia can be used as an equivalent reference.In this study, 3D bone models were reconstructed from CT scans of seven tibiae pairs, and 34 variables consisting of 2D and 3D measurements were measured from various anatomical regions. All 2D measurements, and lateral plateau and distal subchondral bone surface measurements showed insignificant differences (p > 0.05), but the rest of the surfaces showed significant differences (p < 0.05).Our results suggest that the contralateral tibia can be used as a reference especially in surgical applications such as articular reconstructions since the bilateral differences in the subchondral bone surfaces were less than 0.3 mm. The method can also be potentially transferable to other relevant studies that require the accurate quantification of bone bilateral asymmetries.     

Role of muscle mass on sprint performance: gender differences?

The aim of this study was to determine if gender differences in muscle mass explain the gender differences in running and cycling sprint performance. Body composition (dual-energy X-ray absorptiometry), and running (30 and 300 m test) and cycling (Wingate test) sprint performance were assessed in 123 men and 32 women. Peak power (PP) output in the Wingate test expressed per kg of lower extremities lean mass (LM) was similar in males and females (50.4 ± 5.6 and 50.5 ± 6.2 W kg⁻¹, P = 0.88). No gender differences were observed in the slope of the linear relation between LM and PP or mean power output (MP). However, when MP was expressed per kg of LM, the males attained a 22% higher value (26.6 ± 3.4 and 21.9 ± 3.2 W kg⁻¹, P < 0.001). The 30 and 300-m running time divided by the relative lean mass of the lower extremities (RLM = LM × 100/body mass) was significantly lower in males than in females. Although, the slope of the linear relationship between RLM and 300-m running time was not significantly different between genders, the males achieved better performance in the 300-m test than the females. The main factor accounting for gender differences in peak and mean power output during cycling is the muscle mass of the lower extremities. Although, the peak power generating capability of the muscle is similar in males and females, muscle mass only partially explains the gender difference in running sprints, even when expressed as a percentage of the whole body mass.     

Are the effects of training on fat metabolism involved in the improvement of performance during high-intensity exercise?

The objective of the present study was to relate changes in certain muscle characteristics and indicators of metabolism in response to endurance training to the concomitant changes in time to exhaustion (T_lim) at a work rate corresponding to maximal oxygen uptake Eight healthy sedentary subjects pedalled on a cycle ergometer 2 h a day, 6 days a week, for 4 weeks. Training caused increases in O_2peak (by 8%), T_lim (from 299±23 s before to 486±63 s after training), citrate synthase and 3-hydroxyl-acyl-CoA dehydrogenase (HAD) activities (by 54% and 16%, respectively) and capillary density (by 31%). Decreases in activity of lactate dehydrogenase (LDH) and muscle type of LDH (by 24% and 28%, respectively) and the phosphofructokinase/citrate synthase ratio (by 37%) were also observed. Respiratory exchange ratio (RER) tended to be lower (P<0.1) at all relative work rates after training while the corresponding ventilation rates ( E) were unchanged. At the same absolute work rate, RER and E were lower after training (P<0.05). The improvement of T_lim with training was related to the increases in HAD activity (r=0.91, P=0.0043), and to the decreases in RER calculated for Pa_peak (r=0.71, P=0.0496). The present results suggest that the training-induced adaptations in fat metabolism might influence T_lim at a work rate corresponding to O_2peak and stimulate the still debated and incompletely understood role of fat metabolism during short high-intensity exercise     

Are there ethnic differences in deletions in the dystrophin gene?

We studied 160 cases of Duchenne muscular dystrophy (DMD) drawn from all parts of India, using multiplex PCR of 27 exons. Of these, 103 (64.4%) showed intragenic deletions. Most (69.7%) of the deletions involved exons 45–51. The phenotype of cases with deletion of single exons did not differ significantly from those with deletion of multiple exons. The distribution of deletions in studies from different countries was variable, but this was accounted for either by the small number of cases studied, or by fewer exons analyzed. It is concluded that there is likely to be no ethnic difference with respect to deletions in the DMD gene. Am. J. Med. Genet. 68:152–157, 1997 © 1997 Wiley-Liss, Inc.     

Are there sex differences in the reliability of a lifetime history of major depression and its predictors?

BACKGROUND: Although lifetime major depression (LTMD) is assessed with only moderate reliability in community samples, some predictors have emerged for 'reliable' LTMD. Given the large impact of sex on risk for LTMD, it is of interest to know if there are sex differences in the reliability of LTMD and its predictors. METHODS: A total of 5603 members of male-male and male-female twin pairs from a population-based registry were interviewed twice with a mean inter-interview interval of 19 months. LTMD was assessed on each occasion using DSM-III-R criteria. Univariate and multivariate logistic regression analyses were used, combining forward and back-prediction. RESULTS: The long-term test-retest reliability of LTMD was moderate (kappa = +0.48) and did not differ significantly between males and females. In a multivariate model, the significant predictors of a stable diagnosis of LTMD, none of which differed across sex, were younger age at onset, older current age, history of treatment, increasing number of symptoms, level of impairment or level of distress, longer duration of episodes, higher current level of depression and the presence during the depressive episode of sad mood, weight loss, hypersomnia or fatigue. Using these variables, it was not possible to predict 'stably diagnosed' LTMD with both high sensitivity and high specificity. CONCLUSION: In community samples, LTMD is diagnosed with moderate reliability. Although diagnostic stability can be predicted by variables related to severity, distress and treatment-seeking (probably acting to make depressive episodes more 'memorable'), highly accurate prediction of stably diagnosed cases is not possible. Long-term recall is also significantly influenced by current symptoms. Neither the stability of LTMD nor its predictors differ in men and women.     

Are anti-arsonate antibody N-segments selected at both the protein and the DNA level?

The V-D junctional residue at position 99 of AIJ anti-arsonate antibodies with a major cross-reactive idiotype is invariably a serine. This serine is not encoded in the germline of either the V_H or D_H gene segments nor can it be generated by intracodonic recombination between VH and DH. It must, therefore, be generated somatically (N segment addition) and selected by antigen. Sequence data indicate that the serine is frequently encoded by the uncommon TCG triplet. Here J. D. Capra and his colleagues discuss several explanations for the repeated appearance of this unusual codon at this position. They conclude that whatever the mechanism, N segment additions are selected at both protein and DNA levels.     

Are there any gender differences in frequency of self-reported somatic symptoms of depression?

BACKGROUND: The purpose of this study was to evaluate whether self-reported somatic symptoms of depression, as measured by the Beck Depression Inventory-II (BDI-II), are more frequent in women than in men with major depressive disorder. METHODS: A sample of 105 male and 105 female adult psychiatric outpatients diagnosed with major depressive disorder was classified according to endorsed changes in appetite, changes in sleeping pattern, and fatigue (i.e., "somatic depression") symptoms on the BDI-II. RESULTS: The female to male ratio of somatic symptoms was approximately 2:1. Subsequent analyses found that change in appetite robustly distinguished between women and men and that fatigue partially distinguished between women and men. LIMITATIONS: The sample was largely Caucasian and composed of patients with high rates of comorbidity who presented to a service known for specializing in cognitive therapy. CONCLUSIONS: In outpatients with major depressive disorder, the higher prevalence of "somatic depression" in women is largely attributable to changes in appetite.     

Are individual differences in rates of aging greater at older ages?

Although differences among people are frequently assumed to increase with age, cross-sectional comparisons of measures of brain structure and measures of cognitive functioning often reveal similar magnitudes of between-person variability across most of adulthood. The phenomenon of nearly constant variability despite systematically lower means with increased age suggests that individual differences in rates of aging may be relatively small, particularly compared with the individual differences apparent at any age. The current study examined between-person variability in cross-sectional means and in short-term longitudinal changes in 5 cognitive abilities at different ages in adulthood. The variability in both level and change in cognitive performance was found to be similar among healthy adults from 25 to 75 years of age in all 5 cognitive abilities. Furthermore, the correlations between scores at the first and second occasions were very high, and nearly the same magnitude at all ages. The results indicate that between-person differences in short-term cognitive changes are not inevitably greater among healthy older adults than among young adults.     

Sex‐related differences in hemispheric lateralization: A function of physical maturation

The patterns of perceptual asymmetry on three dichotic listening tasks were evaluated to assess the hypothesis that late‐maturing individuals have more clearly lateralized cerebral functions. A total of 64 right‐handed prepubescent (n = 32) and postpubescent (n = 32) males and females, classified by physical exams as early or later maturers, were given dichotic listening tasks of consonant‐vowel syllables (CVs), simple square‐wave tones (STs), and complex square‐wave tones (CTs). Partial support was obtained for the maturation hypothesis, but in unexpected directions. There were no significant differences between early and late maturers in the magnitude of the dichotic right‐ear advantage (REA) for CVs, in either the prepubescent or postpubescent group. Only the postpubescent group obtained a significant REA, regardless of sex or maturation rate. In contrast, maturation rate was related to dichotic ST and CT tone performance. Late maturers demonstrated a stronger left‐ear advantage (LEA) in the prepubescent group, and early maturers demonstrated a stronger LEA in the postpubescent group, regardless of sex. These results suggest that maturation rate may contribute independently to left‐hemisphere and right‐hemisphere lateralization.     

Are proteasomes involved in the formation of the kinetochore?

Proteasomes catalyse the degradation of proteins responsible for the regulation of mitosis enabling the cell to complete cell division. We have studied the effect of an inhibitor of the chymotrypsin-like activity of the proteasome on the trilaminar structure of the kinetochore in HeLa cells. Whereas a role for the proteasome in the degeneration of the kinetochore was predicted, we found instead that the inhibitor strongly retarded kinetochore development. We observed different developmental stages of the kinetochore from the fibrous ball of a prekinetochore to the mature kinetochore in one cell. The data presented here support the proposition that proteasomes are involved in kinetochore formation.accepted for publication by H. C. MacgregorDedicated to the memory of Prof. Dr. Daniel Mazia, a fatherly friend.     

Are sex differences in navigation caused by sexually dimorphic strategies or by differences in the ability to use the strategies?

When navigating, women typically focus on landmarks within the environment, whereas men tend to focus on the Euclidean properties of the environment. However, it is unclear whether these observed differences in navigational skill result from disparate strategies or disparate ability. To remove this confound, the present study required participants to follow either landmark- or Euclidean-based instructions during a navigation task (either in the real-world or on paper). Men performed best when using Euclidean information, whereas women performed best when using landmark information, suggesting a dimorphic capacity to use these 2 types of spatial information. Further, a significant correlation was observed between the mental rotation task and the ability to use Euclidean information, but not the ability to use landmark information.     

Are there meaningful etiological differences within antisocial behavior? Results of a meta-analysis

There is mounting evidence of etiologically driven distinctions between aggressive (AGG) and non-aggressive rule-breaking (RB) forms of antisocial behavior. To date, however, these differences remain somewhat speculative. The current meta-analysis of twin and adoption studies sought to clarify these distinctions by comparing meta-analytic estimates of genetic, shared environmental, and non-shared environmental influences across AGG and RB to more clearly ascertain whether they evidence differential patterns of genetic and environmental influence. A comprehensive literature search resulted in the collection of 103 twin and adoption studies, of which 15 RB samples and 19 AGG samples were ultimately included in the analyses. Results reveal clear evidence of etiological distinctions between AGG and RB. Namely, AGG appears to be a highly heritable condition (genetic factors account for 65% of the variance), with little role for the shared or common environment, particularly after childhood. By contrast, while genetic influences also contribute to RB (48% of the variance), there is an important role for shared environmental effects as well (18% of the variance). Such findings are indicative of meaningful etiologic distinctions between aggressive and rule-breaking forms of antisocial behavior, and underscore the advantage of differentiating between these behavioral subtypes when studying the causal processes that underlie antisocial behavior.     

Are gender differences in depression explained by gender differences in co-morbid anxiety?

BACKGROUND: This review tested the hypothesis that gender differences in depression rates are a function of gender differences in co-morbid anxiety disorders. METHOD: We identified studies using diagnostic criteria, and reporting rates of pure depression, pure anxiety and co-morbid depression and anxiety, separately for females and males. The results of these studies were examined to assess the level of support for the co-morbidity hypothesis. RESULTS: Although some studies supported or partially supported the hypothesis, the methodologically superior studies did not. CONCLUSIONS: We conclude that women are more likely than men to be diagnosed with either disorder alone or co-morbidly. Furthermore, the ratio of women to men who experience anxiety alone or anxiety in combination with depression tends to be higher than the ratio of women to men who experience depression alone. Attempts to explain the gender difference in rates of depression would benefit from an understanding that women also are more likely to experience anxiety.     

Are the biopositive effects of X-rays the only benefits of repetitive mammograms?

Breast cancer mortality rates fell between 1990 and 2000. When something positive occurs in medicine attempts are usually made to explain the observation or claim the credit. In this case, credit has been given to improvements in standard treatments and to increased use of mammography, each said to have made a contribution. Published data on the results of clinical trials utilising high-dose radiation or chemotherapy do not support this position. Improvements in breast cancer mortality are more likely to be the result of the biopositive effects of the low-dose radiation delivered during mammography, based on lower death rates from breast cancer in women subjected to repetitive mammographic screening, albeit with no significant change in all-cause death rates. This is supported by a study in which breast cancer rates were lowered by diagnostic X-rays of the chest.     

Osteomyelitis of the jaw: time to rethink the bone sampling strategy?

This work aims at describing the diversity of osteomyelitis of the jaw (OJ) and at assessing the relevance of a new method designed to avoid salivary contamination during bone sampling in order to improve microbiological analysis and clinical decision-making. We reviewed medical and microbiological data of patients with a suspected OJ based on clinical and/or CT-scan signs and at least one bone sample made for microbiological analysis. During the study period, a new procedure for intraoral bone sampling was elaborated by surgeons and infectious diseases specialists authoring this article (based on stratified samples, cleaning of the surgical site and change of instruments between each sample). A comparison of the microbiological analyses between the two procedures was performed. From 2012 to 2017, 56 patients were included. Median age was 58 years (11–90), sex ratio: 1.24. Main risk factors were having a dental disease (n =?24) or cancer (n =?21). Nineteen patients with the new sample procedure were compared to 37 patients with standard procedure, especially non-cancer patients (n =?16 and 19, respectively). With the new procedure, a median of 3 (1–7) microorganisms per sample was recovered, vs. 7 (1–14) with the former (p <?0.001), a significant decrease of the microbial density was observed for all types of microbes, especially in deeper samples and cultures were more frequently sterile. The way sampling is managed deeply influences microbiological analysis. This strategy facilitates the distinction between pathogens and contaminants and should constitute the first step toward an evidence-based antimicrobial strategy for OJ.     

Can Cantonese rhymes be used in the assessment of hemispheric dominance for language?

English vowels had been proposed in previous studies to be used as a simple tool for the brain mapping of language. A proper fMRI study of Cantonese rhymes, each of which being a required and fundamental unit of a Cantonese syllable, remains to be carried out. Using an auditory task with Cantonese rhymes which carry no semantic meaning, we observed a minimal amount of positive BOLD signal at the caudate nucleus when Cantonese rhymes were contrasted with their corresponding filtered sounds. Typical language activating regions of the prefrontal cortex, the medial prefrontal cortex and the lateral temporal cortex on both left and right sides were not activated by Cantonese rhymes. Based on the absence of brain activation at the typical language areas in the contrast of Cantonese rhymes relative to filtered sounds, the auditory task with Cantonese rhymes may not be a robust tool for the individual clinical assessment of hemispheric dominance for language.