Clinical outcomes following invasive versus noninvasive preoperative stabilization of closed diaphyseal femur fractures.

BACKGROUND: The use of invasive traction (INV-T) to stabilize femur fractures prior to fixation (open reduction and internal fixation, ORIF) remains controversial. Some centers have utilized noninvasive traction (NINV-T) or splinting preoperatively. It is possible that INV-T decreases hemorrhage. However, the use of INV-T in pediatric patients and for femoral neck fractures in adults is associated with worsened outcomes. We hypothesized that there is no difference in the need for transfusion between those who receive INV-T and NINV-T. METHODS: A retrospective study was performed at two level I and one level II trauma center from January 2006 to December 2009. Patients ≥18 years with a closed diaphyseal femur fracture who underwent ORIF within 48 h of arrival were included. Patients were grouped by method of preoperative fracture stabilization. Primary endpoint was need for transfusion. A power analysis found that 94 patients were needed to detect a 25 % difference with 80 % power. RESULTS: Fifty-six (22 %) received INV-T and 199 (78 %) received NINV-T stabilization. No significant differences were found between groups in terms of age, injury severity score, or ORIF method. There was no significant difference between the two groups in the hemoglobin value on arrival, preoperative hemoglobin value, or the difference between admission and preoperative hemoglobin values. We did not find a significant difference in the need for red blood cell transfusion between the two groups. There was no difference in length of stay or discharge destination. CONCLUSION: INV-T is not associated with improved outcomes in adult patients with closed mid-shaft femoral fractures who are operated upon within 48 h of arrival.

Prevalence of somatic small fiber neuropathy in obesity.

BACKGROUND: Somatic cutaneous small sensory fiber neuropathy (SSFN) can be an early manifestation of impaired glucose tolerance and diabetes mellitus and/or insulin resistance among obese subjects and is often associated with pain, wound occurrence and impaired wound healing. It is yet unclear as to whether SSFN is prevalent among obese individuals without glucose and/or insulin dysregulation despite abundant evidence of delayed wound healing. OBJECTIVE: To observe whether there is hypofunctioning of stimulated capsaicin-sensitive cutaneous nerves (small sensory fibers) in obese subjects with/without hyperglycemia and hyperinsulinemia. DESIGN, SETTING AND PARTICIPANTS: Fifty-eight morbidly obese and 15 lean subjects were recruited for small fiber testing of the forearm in a cross-sectional study. Hyperglycemia was observed in 35 obese subjects. Of 25 obese subjects, hyperinsulinemia was noted in 15, 14 of which were hyperglycemic. No subjects demonstrated symptoms/signs of neuropathy over the hairy skin of the forearm. In fact, a neurological examination revealed that 37 subjects were asymptomatic in the legs and only four complained of a neuropathic pain in the foot. Virtually all subjects were exposed to a set of capsaicin-sensitive tests and measures which were identified by capsaicin desensitization procedures. These tests, conducted while in a supine position in bed at the Banner Good Samaritan Medical Center, Phoenix, examined the two principle roles of cutaneous SSFs, namely conveying pain signals to the CNS and controlling local neurogenic vasodilatation (flare; axon-reflex). MAIN OUTCOME MEASURES: Heat-induced pain was assessed by verbal reports of sensation after accommodation and heat-, capsaicin-, and transcutneous stimulation- induced blood flow was measured by laser Doppler flowmetry with probes placed at the site of stimulation and 1 cm remote from the site, the latter to evaluate flare latency and intensity of flare. RESULTS: Significant depression of pain and flare responses were observed in the obese subjects in all but one test. Decreased pain and flare responses were noted in all subjects without hyperglycemia and hyperinsulinemia. Age negatively correlated with capsaicin-induced flare in both the obese and normal groups. CONCLUSION: SSFN was prevalent in the cohort of morbidly obese subjects in a skin area without neurological symptoms or signs and in subjects with/without hyperglycemia and hyperinsulinemia. SSFN may be a serious factor in observations of impaired wound healing among obese subjects, a particularly worrisome problem in an obese aging population given the propensity for small fiber impairment in aging subjects. Small fiber impairment in the younger obese population may signal an early aging phenomenon.

Two type XII-like collagens localize to the surface of banded collagen fibrils.

Two recently identified collagen molecules, termed twelve-like A and twelve-like B (TL-A and TL-B) have properties similar to type XII collagen. These molecules have been localized in human and calf tissues by immunoelectron microscopy. The observations strongly suggest that both molecules are located along the surface of banded collagen fibers. The epitopes recognized by the antibodies are contained in large, nontriple-helical domains at one end of the collagen helix. The epitopes are visualized at a distance from the surface of the banded fibers roughly equal to the length of the nonhelical domains, suggesting that the nonhelical domains extend from the fibril, while the triple-helical domains are likely to bind directly to the fibril surface. Occasionally, both TL-A and TL-B demonstrate periodic distribution along the fibril surface. The period corresponds to the primary interband distance of the banded fibrils. Not all fibrils in a fiber bundle are labeled, nor is the labeling continuous along the length of labeled fibrils. Simultaneous labeling of TL-A and type VI collagen only rarely shows colocalization, suggesting that TL-A and TL-B do not mediate interactions between the type VI collagen beaded filaments and banded collagen fibrils. Also, interfibrillar distances are approximately equivalent in the presence and absence of these type XII-like molecules. While the results do not directly indicate a specific function for these molecules, the localization at the fibril surface suggests that they mediate interactions between the fibrils and other matrix macromolecules or with cells.

Quantitative analysis of DNA secondary structure from solvent-accessible surfaces: the B- to Z-DNA transition as a model.

Solvent structure and its interactions have been suggested to play a critical role in defining the conformation of polynucleotides and other macromolecules. In this work, we attempt to quantitate solvent effects on the well-studied conformational transition between right-handed B- and left-handed Z-DNA. The solvent-accessible surfaces of the hexamer sequences d(m5CG)3, d(CG)3, d(CA)3, and d(TA)3 were calculated in their B- and Z-DNA conformations. The difference in hydration free energies between the Z and the B conformations (delta delta GH(Z-B] was determined from these surfaces to be -0.494 kcal/mol for C-5 methylated d(CG), 0.228 kcal/mol for unmethylated d(CG), 0.756 kcal/mol for d(CA)-d(TG), and 0.896 kcal/mol for d(TA) dinucleotides. These delta delta GH(Z-B) values were compared to the experimental B- to Z-DNA transition energies of -0.56 kcal/mol that we measured for C-5 methylated d(CG), 0.69-1.30 kcal/mol reported for unmethylated d(CG), 1.32-1.48 kcal/mol reported for d(CA)-d(TG), and 2.3-2.4 kcal/mol for d(TA) dinucleotides. From this comparison, we found that the calculated delta delta GH(Z-B) of these dinucleotides could account for the previous observation that the dinucleotides were ordered as d(m5CG) greater than d(CG) greater than d(CA)-d(TG) greater than d(TA) in stability as Z-DNA. Furthermore, we predicted that one of the primary reasons for the inability of d(TA) sequences to form Z-DNA results from a decrease in exposed hydrophilic surfaces of adjacent base pairs due to the C-5 methyl group of thymine; thus, d(UA) dinucleotides should be more stable as Z-DNA than the analogous d(TA) dinucleotides.(ABSTRACT TRUNCATED AT 250 WORDS)