Sex differences in circadian timing systems: Implications for disease

Virtually every eukaryotic cell has an endogenous circadian clock and a biological sex. These cell-based clocks have been conceptualized as oscillators whose phase can be reset by internal signals such as hormones, and external cues such as light. The present review highlights the inter-relationship between circadian clocks and sex differences. In mammals, the suprachiasmatic nucleus (SCN) serves as a master clock synchronizing the phase of clocks throughout the body. Gonadal steroid receptors are expressed in almost every site that receives direct SCN input. Here we review sex differences in the circadian timing system in the hypothalamic–pituitary–gonadal axis (HPG), the hypothalamic–adrenal–pituitary (HPA) axis, and sleep–arousal systems. We also point to ways in which disruption of circadian rhythms within these systems differs in the sexes and is associated with dysfunction and disease. Understanding sex differentiated circadian timing systems can lead to improved treatment strategies for these conditions.     

Cellular adaptation contributes to calorie restriction-induced preservation of skeletal muscle in aged rhesus monkeys

We have previously shown that a 30% reduced calorie intake diet delayed the onset of muscle mass loss in adult monkeys between ~16 and ~22 years of age and prevented multiple cellular phenotypes of aging. In the present study we show the impact of long term (~17 years) calorie restriction (CR) on muscle aging in very old monkeys (27-33 yrs) compared to age-matched Control monkeys fed ad libitum, and describe these data in the context of the whole longitudinal study. Muscle mass was preserved in very old calorie restricted (CR) monkeys compared to age-matched Controls. Immunohistochemical analysis revealed an age-associated increase in the proportion of Type I fibers in the VL from Control animals that was prevented with CR. The cross sectional area (CSA) of Type II fibers was reduced in old CR animals compared to earlier time points (16-22 years of age); however, the total loss in CSA was only 15% in CR animals compared to 36% in old Controls at ~27 years of age. Atrophy was not detected in Type I fibers from either group. Notably, Type I fiber CSA was ~1.6 fold greater in VL from CR animals compared to Control animals at ~27 years of age. The frequency of VL muscle fibers with defects in mitochondrial electron transport system enzymes (ETS(ab)), the absence of cytochrome c oxidase and hyper-reactive succinate dehydrogenase, were identical between Control and CR. We describe changes in ETS(ab) fiber CSA and determined that CR fibers respond differently to the challenge of mitochondrial deficiency. Fiber counts of intact rectus femoris muscles revealed that muscle fiber density was preserved in old CR animals. We suggest that muscle fibers from CR animals are better poised to endure and adapt to changes in muscle mass than those of Control animals.     

Atypical brain activation patterns during a face‐to‐face joint attention game in adults with autism spectrum disorder

Joint attention behaviors include initiating one's own and responding to another's bid for joint attention to an object, person, or topic. Joint attention abilities in autism are pervasively atypical, correlate with development of language and social abilities, and discriminate children with autism from other developmental disorders. Despite the importance of these behaviors, the neural correlates of joint attention in individuals with autism remain unclear. This paucity of data is likely due to the inherent challenge of acquiring data during a real‐time social interaction. We used a novel experimental set‐up in which participants engaged with an experimenter in an interactive face‐to‐face joint attention game during fMRI data acquisition. Both initiating and responding to joint attention behaviors were examined as well as a solo attention (SA) control condition. Participants included adults with autism spectrum disorder (ASD) (n = 13), a mean age‐ and sex‐matched neurotypical group (n = 14), and a separate group of neurotypical adults (n = 22). Significant differences were found between groups within social‐cognitive brain regions, including dorsal medial prefrontal cortex (dMPFC) and right posterior superior temporal sulcus (pSTS), during the RJA as compared to SA conditions. Region‐of‐interest analyses revealed a lack of signal differentiation between joint attention and control conditions within left pSTS and dMPFC in individuals with ASD. Within the pSTS, this lack of differentiation was characterized by reduced activation during joint attention and relative hyper‐activation during SA. These findings suggest a possible failure of developmental neural specialization within the STS and dMPFC to joint attention in ASD. Hum Brain Mapp 34:2511–2523, 2013. © 2012 Wiley Periodicals, Inc.     

Elbow dislocation with irreparable fracture radial head

Background:

Treatment of elbow dislocation with irreparable radial head fracture needs replacement of radial head to achieve stability of elbow. An alternate method in cases of elbow dislocation with radial head fracture can be resection of radial head with repair of medial collateral ligament. We report a retrospective analysis of cases of elbow dislocation with irreparable radial head treated by excision head of radius and repair of MCL.

Materials and Methods:

Nine patients of elbow dislocation with associated irreparable fractures of the head of the radius were included in this analysis (6 F:3 M, Age: 35-47 years). Radial head excision was done through the lateral approach and MCL was sutured using no 3 Ethibond using medial approach. Above elbow plaster was given for 6 weeks and gradual mobilization was done thereafter. All patients were assessed at final followup using Mayo elbow performance score (MEPS).

Results:

Mean followup was 19.55 ± 7.12 months (range 14-36 months). There was no extension deficit when compared to opposite side with mean range of flexion of 138.8° ± 6.97° (range 130 -145°). Mean pronation was 87.7° ± 4.4° (range 80-90°) and mean supination was 87.7 ± 4.62° (range 80-90°). The mean MEPS was 98.8 ± 3.33 (range 90-100). No patient had pain, sensory complaints, subluxation or redislocation. All were able to carry out their daily activities without disability.

Conclusion:

Radial head excision with MCL repair is an acceptable option for treatment of patients with elbow dislocation and irreparable radial head fracture.     

The differential effect of BMI on prosthetic versus autogenous breast reconstruction: A multivariate analysis of 12,986 patients

BackgroundThe comparative safety of breast reconstruction in obese patients remains to be clearly defined. This study utilized multi-institutional data to characterize the effect of body mass index (BMI) on breast reconstruction outcomes.MethodsUtilizing Current Procedural Terminology (CPT) codes, patients undergoing tissue expander, pedicled transverse rectus abdominis myocutaneous (TRAM) flap, latissimus dorsi flap, and free flap breast reconstruction were identified in the National Surgical Quality Improvement Program (NSQIP) database. Patients were stratified as obese (BMI ≥ 30) and non-obese (BMI < 30). Overall postoperative morbidity, flap complications, non-flap complications, and reoperation rates were compared among the groups.ResultsOf 12,986 patients who underwent breast reconstruction, 3636 (28.0%) were obese. Overall morbidity was significantly elevated in obese patients across all forms of reconstruction (p < 0.05). BMI was correlated with increased surgical complications for tissue expander, pedicled TRAM, and free flap reconstructions (OR = 1.09, OR = 1.05, OR = 1.10, respectively; p < 0.05). Medical complications were higher in obese patients undergoing tissue expander and pedicled TRAM reconstructions (p = 0.001 and p < 0.001), but no significant difference was observed in latissimus and free flap reconstruction patients. Compared with obese tissue expander recipients, obese patients reconstructed using autologous tissue had higher rates of reoperations (12.8% versus 9.1%), overall morbidity (18.0% versus 9.5%), surgical (12.7% versus 8.3%), and medical complications (9.0% versus 2.2%).ConclusionsThe NSQIP database allows for evaluation and comparison of reconstructive outcomes in the obese population. Increased BMI was associated with higher morbidity in autologous reconstruction than tissue expander reconstruction. Among autologous procedures, latissimus flaps experienced the lowest captured 30 day morbidity.     

踝关节内侧韧带损伤的治疗

目的 探讨带线锚钉修补踝关节内侧韧带损伤的临床疗效.方法对18例踝关节内侧韧带结构损伤的患者行切开带线锚钉修补手术.结果 18例均得到随访,时间12～24个月.X线片显示胫距关节间隙正常.Baird踝关节功能评分为91～98（93.44±4.91）分,优12例,良6例.结论 带线锚钉修补踝关节内侧韧带损伤操作简单,可以避免踝关节不稳,疗效良好.     

Radiographically Measured Total Knee Wear is Constant and Predicts Failure

Knee wear is commonly measured with the most recent radiograph based on the assumption that wear progresses at a constant rate. Changing patient activity or in vivo polyethylene deterioration are examples of factors that could cause wear rates to change over time. Using six or more radiographs on each of 251 knees over a mean 10-year follow-up, we determined the pattern of polyethylene wear. 92% of knees had linear wear with a mean wear rate of 0.09 ± 0.12 mm/yr. Ten knees (4%) had late accelerated wear. Knees with accelerated wear and those with a wear rate of 0.15 mm/yr or greater had lower survivorship rates. We conclude that wear is linear with rare exceptions and that higher wear is correlated with failure.     

小切口单髁置换术治疗膝关节内侧间室骨性关节炎的早期疗效观察

目的探讨小切口单髁置换术(UKA)治疗膝关节内侧间室骨性关节炎的临床效果。方法对15例(15膝)膝关节内侧间室骨性关节炎采用UKA治疗,术前行膝关节伸直位正侧位、双下肢全长正位、膝关节应力位、髌骨轴位X线片及膝关节MR检查,测量术前及术后膝关节主动活动度,并进行膝关节AKSS评分。结果所有患者随访4~16个月,平均10个月。末次随访时屈曲度与术前相比,差异有统计学意义(P<0.05);末次随访时AKSS评分与术前相比,差异有统计学意义(P<0.05)。结论小切口UKA治疗膝骨性关节炎早期疗效显著,具有创伤小、并发症少、术后功能恢复快的优点,中远期疗效有待于进一步随访。