Pathomechanical aspects of intra-articular calcaneus fractures. Typing, grading and surgical therapy]

The forces to produce fractures of the os calcis are combined compression and shear under a cranio-caudal impulse of 10-40 kN and a short time of stroke about 10-40 ms. The main patterns in biomechanics of calcaneal fractures are the time of stroke and the geometrical position of the foot in the moment of impact. Furthermore individual structural changes of the calcaneal cancellous bone, age, diseases as Diabetes mellitus and vascular obliterations are to be respected. Operative treatment of these fractures needs an understanding of the pathomechanism of the intracalcaneal shear-tension-forces. With plantarflexion of the foot combined with vertical forces within 40 ms to the anterior talocalcanear facette impact-fractures of the anterior part can be expected. These forces develop a posterior directed shear tension parallel to the axis of the os calcis, dividing the bone horizontally in two parts (Typ A, 44-56%), well-known as tongue-type fracture. Compression of the posterior talo-calcaneal joint leads to an impact of this structure producing the joint depression type within about 30 ms in dorsoflexion of the foot (Type B, 42%) together with sagittal shear fractures. High-energy forces are supposed to produce the so-called primary fractures of the sustentacular process in about 10 ms in a supinated position of the foot (Type C, 2-10%); these fractures represent in cases of dislocation an indication for open reduction and internal fixation. In our own experience with 45 cases in 35 patients using the lateral or/and medial approach no infection happened. Palmer's lateral approach was preferred.     

Kinematics of the pelvis. Grading and pathomechanical classification of injuries of the pelvic joints and kinematic and clinical consequences of surgical management]

The concept of kinematics as an idea basic to the operative and non-operative treatment of pelvic trauma, whether a fractures or a pelvic joint dislocation, is gaining ground in thinking and in technical management. The human pelvic ring may be interpreted by kinematic aspects as a three-bar linkage moving with three bony links (sacrum and both ossa coxae), (n = 3), in three real joints (symphysis pubis and both sacroiliac joints, (g = 3), as a transformer of great forces into small movements, and as a halter under periodic oscillating femoral impulses. The closed kinematic chain of the symmetric pelvic girdle possesses eight degrees of freedom (sigma g f = 8) subject to two external parameters of influence (F = 2), the gravity exerted by the trunk acting on the sacrum as a driving link caudally and ventrally, jointly creating a ring tension inside the pelvis. The guided linkage allows synthesis of a kinematic number and a positive movement equation in accordance with the spatial kinematic rule: F = 6(n-1)-6g + sigma g f = 2. This formula is applied to the investigation of all possible of pelvic joint dislocations types and fractures, and different forms of surgical treatment are described.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mercury Concentrations in Quagga Mussels, Dreissena bugensis, from Lakes Mead, Mohave and Havasu

The recent invasion of the Dressenid species, the quagga mussel, Dreissena bugensis, into Lakes Mead, Mohave and Havasu has raised questions about their ability to alter contaminant cycling. Mussels were collected from 25 locations in the three lakes. The overall average was 0.036 ± 0.016 μg g⁻¹ Hg dry wt. The range of the three lakes was from 0.014–0.093 μg g⁻¹ Hg dry wt. There were no significant differences in mercury concentrations among the three lakes (F = 0.07; p = 0.794). From this baseline data of contaminants in quagga mussels from the lower Colorado River, this species may be used to biomonitor lake health.     

Deletion of the ferric uptake regulator Fur impairs the in vitro growth and virulence of Actinobacillus pleuropneumoniae

In order to investigate the role of the ferric uptake regulator Fur in the porcine lung pathogen Actinobacillus pleuropneumoniae, we constructed an isogenic in-frame deletion mutant, A. pleuropneumoniae Deltafur. This mutant showed constitutive expression of transferrin-binding proteins, growth deficiencies in vitro, and reduced virulence in an aerosol infection model.     

Implications of the New Centers for Disease Control and Prevention Blood Lead Reference Value

The Centers for Disease Control and Prevention recently established a new reference value (≥ 5 μg/dL) as the standard for identifying children with elevated blood lead levels (EBLs). At present, 535 000 US children aged 1 to 5 years (2.6%) are estimated to have EBLs according to the new standard, versus 0.8% according to the previous standard (≥ 10 μg/dL). Because EBLs signify the threshold for public health intervention, this new definition increases demands on lead poisoning prevention efforts. Primary prevention has been proven to reduce lead poisoning cases and is also cost effective; however, federal budget cuts threaten the existence of such programs. Protection for the highest-risk children necessitates a reinstatement of federal funding to previous levels.In May 2012, officials of the Centers for Disease Control and Prevention (CDC) announced that they had accepted the recommendations set forth by the Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP) for (1) the discontinuation of the term blood lead “level of concern,” to acknowledge that there is no safe level of lead exposure, and (2) the use of a new reference value for the identification of children with elevated blood lead levels (EBLs).1 The level of concern, previously defined as 10 micrograms of lead per deciliter of blood, was established by the CDC as the EBL that should initiate a public health response and had been previously unchanged since 1991.2 By contrast, the new reference value is 5 micrograms per deciliter.1 Figure 1 depicts the decline in CDC-recommended blood lead level (BLL) action levels, a drop of more than 90% over the past several decades.3,4 Regardless of the action level of the time, childhood EBLs have long been targeted for complete elimination.5–9Open in a separate windowFIGURE 1—Trends in Centers for Disease Control and Prevention’s childhood blood lead level of concern: United States, 1960–2014.     

Neutrophil stimulation with granulocyte colony-stimulating factor worsens ventilator-induced lung injury and mortality in rats

BACKGROUND: Based on the association between the neutrophil and ventilator-induced lung injury, the authors hypothesized that neutrophil inhibition with fucoidin would be beneficial and stimulation with granulocyte colony-stimulating factor (G-CSF) would be harmful in a rat model of lethal ventilator-induced lung injury. METHODS: Animals (n = 111) were randomly assigned to be pretreated with fucoidin, G-CSF, or placebo (control) before 4 h of low-tidal-volume (10 ml/kg) or high-tidal-volume (40 ml/kg) mechanical ventilation. RESULTS: All low-volume animals survived. With high volumes, compared with controls, fucoidin did not improve survival (3 of 20 control animals and 5 of 20 fucoidin animals died; P = 0.51) but G-CSF significantly worsened it (18 of 22 animals died; P < 0.001). Circulating neutrophils were increased early with G-CSF and late with fucoidin with low and high tidal volumes (P < 0.05 for each treatment and tidal volume). Fucoidin decreased lung neutrophils, but these were only significant with high tidal volumes, whereas G-CSF increased lung neutrophils but only significantly with low tidal volumes (P < or = 0.01 for each). Fucoidin did not alter any cardiopulmonary measure significantly. Compared with control, G-CSF increased airway pressures with high tidal volumes and worsened lung edema and arterial oxygen with both tidal volumes (P < 0.05 for each). CONCLUSIONS: In this model, neutrophil stimulation by G-CSF increased lung dysfunction and with high tidal volumes worsened survival rates. Extrapolated clinically, neutrophil stimulation either by agents such as G-CSF or conditions such as sepsis may aggravate ventilator-induced lung injury.     

Granulocyte colony-stimulating factor has differing effects comparing intravascular versus extravascular models of sepsis

BACKGROUND: Previously, neutrophil stimulation with granulocyte colony-stimulating factor (G-CSF) pretreatment increased survival rates in canines challenged with intraperitoneal or intrabronchial Escherichia coli and in rats challenged with intrabronchial Staphylococcus aureus. We investigated whether G-CSF pretreatment would be beneficial with intravascular challenge in these models. METHODS: Animals were randomized to G-CSF or placebo pretreatment followed by intravenous E. coli challenge in canines (n = 24) or intravenous or intrabronchial S. aureus challenge in rats (n = 273). All animals were treated with antibiotics. RESULTS: In canines, G-CSF before intravenous E. coli did not decrease mortality rates (7 of 12 [58%] G-CSF vs. 5 of 12 [42%] controls), which contrasted with prior reductions during extravascular infection (10 of 35 [29%] G-CSF vs. 37 of 65 [57%] controls). Consistent with the present and previously published studies in canines, in rats, G-CSF decreased mortality rates with intrabronchial S. aureus (22 of 90 [24%] G-CSF vs. 26 of 51 [51%] controls, p = 0.009) but did not decrease them with intravenous infection (34 of 67 [50%] G-CSF vs. 27 of 65 [42%] controls, p = 0.2) in patterns that were very different (p = 0.005 for the effects of G-CSF with intravascular vs. intrabronchial S. aureus). CONCLUSION: In contrast to extravascular infection, sepsis with intravascular E. coli in canines and S. aureus in rats may not provide a compartmentalized nidus of bacteria on which G-CSF-stimulated neutrophils can exert a beneficial antimicrobial effect. Extrapolated clinically, a proinflammatory agent like G-CSF may be most beneficial with sepsis related primarily to a compartmentalized extravascular site of infection.     

Risk management for the endoscopy center

Risk management, as applied to practice in the endoscopy center, is a framework of processes that attempt to minimize medical errors, prevent adverse events and patient injury, reduce the probability of malpractice actions being brought, and limit the financial and personal psychological costs that accompany malpractice lawsuits. This article summarizes the components of these processes, building on a foundation of applied legal concepts and pertinent malpractice claim data.