FTIR imaging detects diet and genotype-dependent chemical composition changes in wild type and mutant C. elegans strains.

This study focuses on the use of Fourier Transform Infrared (FTIR) microspectroscopy to determine chemical changes induced in the nematode Caenorhabditis elegans by supplementation of C. elegans maintenance media (CeMM) by Eicosapentaenoic acid (EPA). Wild-type C. elegans (N2) and mutant strains (tub-1 and fat-3) were grown in CeMM alone, and CeMM supplemented with EPA at 25 or 100 µM. Feeding was performed for 72 h. FTIR imaging was performed in transmission mode on individual worms. The FTIR imaging analysis of wild-type animals revealed the presence of vibrations assigned to unsaturated fatty acids, specifically bands at 3008 cm-1 ([double bond, length as m-dash]C-H, olefinic stretch) and 1744 cm-1 (C[double bond, length as m-dash]O, unsaturated fatty acids). It confirmed previously reported synthesis of unsaturated fatty acids in wild-type C. elegans. For the FTIR spectra of mutant strains, these vibrations were absent or present only as very small shoulder, which indicates that tub-1 and fat-3 synthesize essentially saturated fatty acids as indicated by the presence of -CH2 and C[double bond, length as m-dash]O vibrations. These results are in agreement with previous studies which reported that these mutants have altered lipid compositions. Principal component analysis showed differences in chemical composition between wild-type and mutant strains as well as between mutant strains cultured in normal CeMM and those cultured in CeMM supplemented with EPA. This study demonstrated the usefulness of FTIR microspectroscopy to investigate fat metabolism in C. elegans.

Impact of a multifaceted prevention program on ventilator-associated pneumonia including selective oropharyngeal decontamination.

PURPOSE: We describe the impact of a multifaceted program for decreasing ventilator-associated pneumonia (VAP) after implementing nine preventive measures, including selective oropharyngeal decontamination (SOD). METHODS: We compared VAP rates during an 8-month pre-intervention period, a 12-month intervention period, and an 11-month post-intervention period in a cohort of patients who received mechanical ventilation (MV) for > 48 h. The primary objective was to assess the effect on first VAP occurrence, using a Cox cause-specific proportional hazards model. Secondary objectives included the impact on emergence of antimicrobial resistance, antibiotic consumption, duration of MV, and ICU mortality. RESULTS: Pre-intervention, intervention and post-intervention VAP rates were 24.0, 11.0 and 3.9 VAP episodes per 1000 ventilation-days, respectively. VAP rates decreased by 56% [hazard ratio (HR) 0.44, 95% CI 0.29-0.65; P < 0.001] in the intervention and by 85% (HR 0.15, 95% CI 0.08-0.27; P < 0.001) in the post-intervention periods. During the intervention period, VAP rates decreased by 42% (HR 0.58, 95% CI 0.38-0.87; P < 0.001) after implementation of eight preventive measures without SOD, and by 70% after adding SOD (HR 0.30, 95% CI 0.13-0.72; P < 0.001) compared to the pre-intervention period. The incidence density of intrinsically resistant bacteria (to colistin or tobramycin) did not increase. We documented a significant reduction of days of therapy per 1000 patient-days of broad-spectrum antibiotic used to treat lower respiratory tract infection (P < 0.028), median duration of MV (from 7.1 to 6.4 days; P < 0.003) and ICU mortality (from 16.2 to 13.5%; P < 0.049) for patients ventilated > 48 h between the pre- and post-intervention periods. CONCLUSIONS: Our preventive program produced a sustained decrease in VAP incidence. SOD provides an additive value.

An energy algorithm improves symptoms in some patients with gastroparesis and treated with gastric electrical stimulation.

Gastric electrical stimulation (GES) is effective to improve symptoms of nausea and vomiting in most patients, but very little is known about the effect of varying stimulation parameters. We analysed stimulation parameters in a pilot study of 22 patients (12 idiopathic, four diabetic and four postsurgical) with drug-refractory gastroparesis who did not respond optimally to initial settings. Patients underwent high-frequency/low energy GES using identical initial stimulation parameters: 5 mA of current, 330 micros pulse width, 14 Hz for 0.1 s on and 5.0 s off. Due to lack on optimal response, 22 patients underwent alteration of an algorithm using stimulation parameters. At follow-up (mean of 4.3 years) a dose-response relationship for charge, power and energy were compared with baseline for the whole group and for each diagnostic subgroup by anova data are reported as mean +/- SE. Based on the mean of individual dose-response curves, differences in data are charge, current per pulse and energy per pulse were noted for the whole group at follow up vs baseline. The subgroup of patients with postsurgical gastroparesis required the most energy using the algorithm. In conclusion, an algorithmic approach to identify optimal stimulation parameters in GES for individual patients is associated with symptom improvement. Also, certain subgroups appear to have different energy parameters. Based on this preliminary data, the use of an algorithm for some patients with GES is feasible and may have potential for clinical application. A randomized-controlled trial of different stimulation parameters for GES seems warranted.

Ankle arthrodesis: indications and techniques.

Patients with ankle arthritis and deformity can experience severe pain and functional disability. Those patients who do not respond to nonoperative treatment modalities are candidates for ankle arthrodesis, provided pathologic changes in the subtalar region can be ruled out. Several techniques are available for performing the procedure; the most successful combine an open approach with compression and internal fixation. The foot must be positioned with regard to overall limb alignment and in the optimal position for function. A nonunion rate as high as 40% has been reported. Osteonecrosis of the talus and smoking are known risk factors for nonunion. When good surgical technique is used in carefully selected patients, ankle arthrodesis can be a reliable procedure for the relief of functionally disabling ankle arthritis, deformity, and pain.

Wound-healing risk factors after open reduction and internal fixation of calcaneal fractures: does correction of Bohler's angle alter outcomes?

The study reviewed in this article evaluated a group of patients who underwent surgical therapy for calcaneal fractures at a Level I trauma center. One group of patients was treated after outpatient referral to the center, whereas the other group was admitted to, and underwent surgery at, the center. This study attempted to determine which patient risk factors or injury characteristics might lead to an increased rate of wound-healing complications. Bohler's angle is a classic radiographic method of determining the severity of calcaneal injury in this group of patients. The question posed by the authors of this study was: Does a drastic correction in Bohler's angle lead to an increased incidence of wound-healing complications? The authors do not recommend undercorrection of Bohler's angle but urge avoidance of overcorrection and stress the importance of early surgical fixation after lateral skin wrinkling is found.

Medial malleolar osteotomy for exposure of complex talar body fractures.

Traditional surgical approaches to the talus often fail to afford adequate exposure of the talar body, especially in the case of complex talar body fractures. Preservation of the remaining blood supply to the talus is a main concern during operative repair and can be difficult to accomplish when multiple approaches and forceful manipulations are required to gain satisfactory exposure. A medial malleolar osteotomy was used to gain access to the talar body in situations in which the traditional approaches did not provide adequate exposure. We describe our technique in a small series of patients.

Soft tissue injuries with the use of safe corridors for transfixion wire placement during external fixation of distal tibia fractures: an anatomic study.

OBJECTIVES: To determine which soft tissue structures are at risk and when joint violation can occur during small wire placement for hybrid external fixation of distal tibial fractures while adhering to published guidelines. DESIGN: Cadaver anatomic experiment. SETTING: University orthopaedic program. SUJBECTS: Five embalmed cadavers. INTERVENTION: Placement of small wire transfixion pins in the distal tibia. MAIN OUTCOME MEASUREMENTS: Dissection and measurements. METHODS: Four orthopaedic surgeons were shown diagrams that have been widely accepted as allowing for placement of transfixion pins in the distal tibia through safe corridors. Each of the orthopaedic surgeons was then asked to place two transfixion pins into each of five cadaver legs in a position that would provide stable external fixation of the metaphysis to the diaphysis with a circular fixator (forty pins total) for a distal tibial fracture within five centimeters of the plafond. The specimens were dissected, and pins impaling neurovascular structures, tendons, or the ankle capsule were recorded. The superior capsular synovial reflections were measured from the anterior joint line and the tip of the medial malleolus. These measurements were also performed on arthrograms of two extremities before their dissection. RESULTS: Fifty-five percent of the pins placed impaled at least one tendon that crosses the ankle joint. Neurovascular structures that were impaled included the saphenous vein (+/-10.5 percent) and the superficial peroneal nerve (+/-7.5 percent). One pin violated the superior capsular synovial reflection, which was an average of thirty-two millimeters (+/-1.58 millimeters) from the tip of the medial malleolus and twenty-one millimeters (+/-1.63 millimeters) from the anteromedial joint line. CONCLUSIONS: This study shows that tendons and neurovascular structures above the ankle are at risk during small transfixion pin placement, even when using safe corridors. Pins placed within two centimeters of the anterior joint line or three centimeters from the medial malleolus may be intracapsular.

Missed and associated injuries after subtalar dislocation: the role of CT.

Subtalar joint dislocation (STJD) is an uncommon injury, but carries with it a potential for significant functional disability. We hypothesized that a significant number of injuries associated with subtalar joint dislocation may be unrecognized by plain radiographic examination. Therefore, we reviewed the records of all STJDs over a three-year period, identifying nine cases. The majority of injuries occurred in men (78%) with a mean age of 29 years. Overall, the mean age at injury was 32 years. The right lower extremity was most frequently injured (87.5%). Plain films initially diagnosed a STJ dislocation in all patients. A CT scan was performed in all cases. In 100% of patients, CT identified additional injuries missed on initial plain radiographs. In 44% of patient, new information gathered by CT dictated a change in treatment. Based on our findings, we conclude that CT is an invaluable tool to assess for associated injuries in STJ dislocation, and should be performed in all cases of STJ dislocation.

Wound-healing risk factors after open reduction and internal fixation of calcaneal fractures.

This retrospective study investigated outcomes of wound healing in a series of 63 consecutive patients with 64 fractures of the calcaneus who underwent open reduction and internal fixation done by two surgeons experienced in this fracture during a 3-year period. Thirty-nine patients were managed preoperatively as outpatient referrals before surgery. Twenty-four patients were admitted directly to the trauma service and were managed as inpatients preoperatively. Minimum patient follow-up was 6 months, with an average follow-up of 18 months. A trend correlating the time between injury and operative intervention with the incidence of complications in wounds was noted; the incidence rose in patients who underwent surgery >5 days after their injury. Two-layered closures had a lower incidence of dehiscence compared to single-layered tension-relieving sutures. Patients with a higher body-mass index (BMI) (kg/ m2) took longer to heal their wounds. Strong trends were noted to link BMI and severity of fractures. In the outpatient group, a history of active smoking preoperatively correlated with increased time to wound healing. In 43 patients, there were no wound-healing complications. In 21 feet, there were varying degrees of wound dehiscence. Average wound healing took 47 days. Risk factors for complications in the wound after calcaneal open reduction and internal fixation include single layered closure, high BMI, extended time between injury and surgery, and smoking. Age, type of immobilization, medical illness (including diabetes), type of bone graft, or use of a Hemovac did not influence wound healing.

The use of polymerase chain reaction generated nucleotide sequences as probes for hybridization.

In this report a rapid, simple and economical means of preparing a cDNA probe of specified length, sequence and specific activity is described. The process involves the use of a polymerase chain reaction to incorporate radiolabelled nucleotides into a single stranded or double stranded cDNA sequence. A pair of oligonucleotide primers are synthesized, flanking the sense and antisense strands of a selected sequence. The primers are then used with a cloned DNA fragment or a cellular source of RNA or DNA as a template to amplify the specific gene sequence. The sequence to be used as a probe is selected from the known sequence using free energy calculations of the secondary structure. The calculation of free energy predicts regions of stable secondary structure which may hinder transcription and thus are to be avoided. By selecting the distance between primers the probe length can be controlled to allow adequate probe permeability into tissue samples. The specific region of the gene sequence can be chosen to differentiate between closely related sequences by avoiding areas of homology. Altering the concentration of a radiolabelled nucleotide allows direct control of probe specific activity. The use of asymmetric PCR allows the preferential generation of an antisense single stranded cDNA sequence for a higher sensitivity in the detection of low abundance mRNA. This report highlights the advantage of this technique in generating probes for in situ hybridization. However, any technique that relies on homology for detection of sequences, such as Northern and Southern blotting could also utilize this technique.

Fractures of the vertebrae with spinal cord injuries in patients with ankylosing spondylitis: imaging findings.

Ankylosing spondylitis is a systemic rheumatologic disorder of adults that results in disease-specific inflammation and eventual ossification at the site of ligamentous insertion into bone. The resulting spinal ankylosis causes biomechanical alterations that predispose the patient to serious spinal injury even in the presence of minor trauma. With the loss of spinal flexibility and increased bone fragility, there is a propensity for vertebral fracture, instability, and increased neurologic complications. Illustrative examples of the imaging modalities are presented, as they contribute to the detection of fractures and spinal cord injuries in patients with ankylosing spondylitis.

Rapid quantitation and monitoring of plasmid DNA using an ultrasensitive DNA-binding dye.

A sensitive fluorescence-based method for monitoring plasmid DNA during production was investigated. This simple method of assaying for plasmid DNA allows rapid monitoring of plasmid yields from a recombinant Escherichia coli fed-batch fermentation. The assay has several advantages over traditional methods of plasmid DNA measurement. The fluorescent dye is highly specific and can measure total plasmid DNA concentration in about 5 min. The assay is sensitive over a wide range of plasmid concentrations of between 15 and 280 ng/mL, even in the presence of impurities that occur within alkaline lysate preparations. The technique can also be applied to monitoring fermentation and downstream purification steps.