不同手术方法治疗不稳定Hangman骨折的疗效观察

目的探讨不同手术方法治疗不稳定Hangman骨折的临床疗效。方法 14例不稳定Hangman骨折患者根据Levine-Edwards分型:Ⅱ型7例,ⅡA型5例,Ⅲ型2例。4例行后路C2,3椎弓根螺钉内固定术,7例行前路C2,3间盘摘除减压植骨融合内固定术,3例行前后路联合手术。结果患者均获随访,时间3~24个月。1例患者术后3个月单侧椎弓根处可见模糊骨折线,13例患者均达到骨性愈合。术中及术后未出现椎动脉、脊髓损伤及脑脊液漏等并发症,未发生钢板螺钉断裂内固定失效等现象。结论对于不稳定Hangman骨折无论是采取前路或者后路手术均可使骨折达到骨性愈合,对严重骨折伴脱位Hangman骨折可以采取前后路联合的手术方式。     

Sacral insufficiency fractures: an unsuspected cause of low back pain [clinical conference]

We describe 10 cases of sacral fractures diagnosed within the rheumatology department at Southend Hospital over the last 5 yr. All presented with sudden-onset low back pain. The majority were elderly, frail, with chronic inflammatory disease (six with rheumatoid arthritis, one with polymyalgia rheumatica, one with vasculitis) and had received steroids. Diagnosis was delayed by the inability of plain radiographs to show these fractures and was ultimately demonstrated by technetium scintigraphy/computed tomography scan. We feel that this diagnosis should be considered in elderly patients with rheumatoid arthritis or other risk factors for osteoporosis who present with low back pain and sacral tenderness. Further clues may be parasymphyseal tenderness (suggesting associated pubic ramus fracture), elevated alkaline phosphatase and plain radiograph showing pubic ramus fractures or parasymphyseal sclerosis. Patients with this complication generally have a poor prognosis and two of our patients have died. Seven required in-patient stay (mean 20 days; range 14-41). The mortality, morbidity and costs incurred in management may be comparable to those of femoral neck fractures.      

Inhibition of Na+/Ca2+ exchange in membrane vesicle and papillary muscle preparations from guinea pig heart by analogs of amiloride.

Na+/Ca2+ exchange is inhibited in both guinea pig cardiac membrane vesicles and papillary muscles in a concentration-dependent fashion by several analogs of the pyrazine diuretic amiloride. Structure/activity studies based on transport measurements in vesicles prepared from guinea pig left ventricle indicate that hydrophobic substitutions at the terminal nitrogen atom of the guanidinium moiety of amiloride improved the inhibitory potency almost 100-fold over that of the parent compound. 3',4'- Dichlorobenzamil ( DCB ) is one of the most active inhibitors (IC50 = 17 microM). In electrically stimulated papillary muscles isolated from guinea pig heart, 10-40 microM DCB decreases contractile force. At 100 microM inhibitor, diastolic tension is significantly increased. The positive inotropic responses to veratridine and ouabain are inhibited by 20 and 40 microM DCB . Since the responses to these interventions were a consequence of increased intracellular Na+ concentration, these data indicate that DCB is an inhibitor of Na+-dependent Ca2+ influx in the intact tissue. Interpretation of mechanical responses elicited by paired pulses suggests that 40 microM but not 100 microM DCB decreases release of Ca2+ from the sarcoplasmic reticulum. The mechanical data obtained with concentrations of DCB that inhibited Na+/Ca2+ exchange in vesicles suggest that a significant amount of Ca2+ can enter the cardiac cell via Na+/Ca2+ exchange under normal conditions and that this transport system may be an important source of Ca2+ supplying the sarcoplasmic reticulum in guinea pig heart. Moreover, these amiloride analogs function as potent inhibitors of the positive inotropic effect caused by increased intracellular Na+ concentration.     

Persistent lipophilic environmental chemicals and endometriosis: the ENDO Study

Background: An equivocal literature exists regarding the relation between persistent organochlorine pollutants (POPs) and endometriosis in women, with differences attributed to methodologies.Objectives: We assessed the association between POPs and the odds of an endometriosis diagnosis and the consistency of findings by biological medium and study cohort.Methods: Using a matched cohort design, we assembled an operative cohort of women 18–44 years of age undergoing laparoscopy or laparotomy at 14 participating clinical centers from 2007 to 2009 and a population-based cohort matched on age and residence within a 50-mile catchment area of the clinical centers. Endometriosis was defined as visualized disease in the operative cohort and as diagnosed by magnetic resonance imaging in the population cohort. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for each POP in relation to an endometriosis diagnosis, with separate models run for each medium (omental fat in the operative cohort, serum in both cohorts) and cohort. Adjusted models included age, body mass index, breast-feeding conditional on parity, cotinine, and lipids.Results: Concentrations were higher in omental fat than in serum for all POPs. In the operative cohort, γ-hexachlorocyclohexane (γ-HCH) was the only POP with a significant positive association with endometriosis [per 1-SD increase in log-transformed γ-HCH: adjusted OR (AOR) = 1.27; 95% CI: 1.01, 1.59]; β-HCH was the only significant predictor in the population cohort (per 1-SD increase in log-transformed β-HCH: AOR = 1.72; 95% CI: 1.09, 2.72).Conclusions: Using a matched cohort design, we found that cohort-specific and biological-medium–specific POPs were associated with endometriosis, underscoring the importance of methodological considerations when interpreting findings.     

In vivo performance of a muscle-powered drive system for implantable blood pumps

A unique biomechanical implant has been developed to convert muscle power into hydraulic energy for the purpose of driving an implanted blood pump. This device, called a muscle energy converter (MEC), is designed to attach to the humeral insertion of the latissimus dorsi (LD) muscle, so that stimulated contractions cause a rotary cam to compress a fluid-filled bellows. Here we report results from the latest in a series of canine implant trials where the MEC was connected to an adjustable pressure load to measure power output and assess long-term function. Full-length (2 cm) actuator strokes were maintained for a period of 1 month with no discernable discomfort to the animal. Load conditions were cycled periodically to measure stroke work capacity and pressure production. The peak driveline pressure recorded in this experiment was 1743 mm Hg. Steady state power generation was measured to 478 +/- 21 mJ/stroke (mean +/- SD) with stroke work levels reaching 785 mJ in one test. Normal left and right ventricular stroke work levels in dogs this size (35 kg) are 700 and 150 mJ, respectively. These data confirm that MEC/LD power levels--maintained in tandem with an appropriate cardiac assist device--are sufficient to provide significant long-term circulatory support. Further testing, however, is still needed to demonstrate the long-term stability of this drive system.     

Child nutritional status among births exceeding ideal family size in a high fertility population

Ideal family size (IFS) is measured in social surveys to indicate unmet need for contraception and impending shifts in fertility behaviour. Whether exceeding IFS affects parental behaviour in ways that result in lower investments in child nutrition, well‐being, and educational attainment is not known. This study examines parental IFS and the association between exceeding stated ideals and child nutritional status in a high‐fertility, high‐mortality population in the Bolivian Amazon. Height‐for‐age z‐scores, weight‐for‐age z‐scores, weight‐for‐height z‐scores, stunting, haemoglobin, and anaemia status in 638 children aged 0–5 years are predicted as a function of birth order in relation to parental IFS, adjusting for household characteristics and mother and child random effects. Children of birth orders above paternal IFS experience higher weight‐for‐age z‐scores when living further away from the market town of San Borja, consistent with underlying motivations for higher IFS and lower human capital investment in children in more remote areas (β = .009, p = .027). Overall, we find no statistical evidence that birth orders in excess of parental ideals are associated with compromised child nutrition below age 2, a period of intensive breastfeeding in this population. Despite a vulnerability to nutritional deficiencies postweaning for children age 2–5, there was no association between birth order in excess of parental ideals and lower nutritional status. Further studies examining this association at various stages of the fertility transition will elucidate whether reported ideal or optimal family sizes are flexible as trade‐offs between quality and quantity of children shift during the transition to lower fertility.     

Energetic costs of testosterone in two subsistence populations

Objective

Testosterone plays a role in mediating energetic trade-offs between growth, maintenance, and reproduction. Investments in a high testosterone phenotype trade-off against other functions, particularly survival-enhancing immune function and cellular repair; thus only individuals in good condition can maintain both a high testosterone phenotype and somatic maintenance. While these effects are observed in experimental manipulations, they are difficult to demonstrate in free-living animals, particularly in humans. We hypothesize that individuals with higher testosterone will have higher energetic expenditures than those with lower testosterone.

Methods

Total energetic expenditure (TEE) was quantified using doubly labeled water in n = 40 Tsimane forager-horticulturalists (50% male, 18–87 years) and n = 11 Hadza hunter-gatherers (100% male, 18–65 years), two populations living subsistence lifestyles, high levels of physical activity, and high infectious burden. Urinary testosterone, TEE, body composition, and physical activity were measured to assess potential physical and behavioral costs associated with a high testosterone phenotype.

Results

Endogenous male testosterone was significantly associated with energetic expenditure, controlling for fat free mass; a one standard deviation increase in testosterone is associated with the expenditure of an additional 96–240 calories per day.

Discussion

These results suggest that a high testosterone phenotype, while beneficial for male reproduction, is also energetically expensive and likely only possible to maintain in healthy males in robust condition.