Parallel And Divergent Morphological Adaptations Underlying The Evolution of Jumping Ability in Ants.

Jumping is a rapid locomotory mode widespread in terrestrial organisms. However, it is a rare specialization in ants. Forward jumping has been reported within four distantly related ant genera: Gigantiops, Harpegnathos, Myrmecia, and Odontomachus. The temporal engagement of legs/body parts during jump, however, varies across these genera. It is unknown what morphological adaptations underlie such behaviors and whether jumping in ants is solely driven directly by muscle contraction or additionally relies on elastic recoil mechanism. We investigated the morphological adaptations for jumping behavior by comparing differences in the locomotory musculature between jumping and non-jumping relatives using X-ray micro-CT and 3D morphometrics. We found that the size-specific volumes of the trochanter depressor muscle (scm6) of the middle and hind legs are 3-5 times larger in jumping ants, and that one coxal remotor muscle (scm2) is reduced in volume in the middle and/or hind legs. Notably, the enlargement in the volume of other muscle groups is directly linked to the legs or body parts engaged during the jump. Furthermore, a direct comparison of the muscle architecture revealed two significant differences between jumping vs. non-jumping ants: First, the relative Physiological Cross-Sectional Area (PCSA) of the trochanter depressor muscles of all three legs were larger in jumping ants, except in the front legs of Odontomachus rixosus and Myrmecia nigrocincta; second, the relative muscle fiber length was shorter in jumping ants compared to non-jumping counterparts, except in the front legs of O. rixosus and M. nigrocincta. These results suggest that the difference in relative muscle volume in jumping ants is largely invested in the area (PCSA), and not in fiber length. There was no clear difference in the pennation angle between jumping and non-jumping ants. Additionally, we report that the hind leg length relative to body length was longer in jumping ants. Based on direct comparison of the observed vs. possible work and power output during jumps, we surmise that direct muscle contractions suffice to explain jumping performance in three species, except for O. rixosus, where the lack of data on jumping performance prevents us from drawing definitive conclusions for this particular species. We suggest that increased investment in jumping-relevant musculature is a primary morphological adaptation that separates jumping from non-jumping ants. These results elucidate the common and idiosyncratic morphological changes underlying this rare adaptation in ants. まとぅみ (Okinawan language-Uchinaaguchi) (Japanese) РЕЗЮМЕ (Kazakh) ZUSAMMENFASSUNG (German).

Current practice: postoperative and return to play trends after ACL reconstruction by fellowship-trained sports surgeons.

PURPOSE: Advances in anterior cruciate ligament (ACL) reconstruction have allowed for many progressions in postoperative management. However, there is no standardized protocol for immediate postoperative management or return to play. Our objective was to evaluate current trends in immediate postoperative and return to sport practices after ACL reconstruction. LEVEL OF EVIDENCE: Cross sectional study, Level IV. METHODS: Surveys were obtained from four large sports fellowship alumni networks. Demographics included years of practice and ACLs performed per year. Postoperative questions included weight bearing status, brace use and continuous passive motion (CPM) use. Return to play included time for return, brace use and metrics used for clearance to sport. RESULTS: A total of 143 surveys were completed (32% response rate). Average years in practice were 15.1 years. Average ACL reconstructions performed per year was 20-50 in 44% and 50-100 in 29%. 26% used CPM in all patients, 8% if concomitant meniscal repair and 66% never. Bracing after surgery was used in 84% and 48% after return to play. Return to play was allowed at 6-9 months in 67% and overall 94% from 6 to 12 months. No consensus on return to play metrics was used, with the hop test being most important followed by specific time point after surgery. CONCLUSION: Immediate weight bearing after surgery is commonplace with intermittent CPM use. Bracing is common postoperatively and half the time with return to play. Return to play is typically allowed after at least 6 months with no consensus on return to sport metrics. Years after fellowship and ACLs performed yearly had no correlation with postoperative practices.

The utility of botulinum toxin A in the repair of distal biceps tendon ruptures.

PURPOSE: The purpose of our study is to report the outcomes and complications in patients who underwent distal biceps tendon repair with the use of Botulinum toxin A (BoNT-A) as an adjunct to surgery. METHODS: A retrospective review of 14 patients who underwent 15 distal biceps tendon repairs was performed. All repaired tendons had their correlating muscle bellies injected intraoperatively with a mixture of 100U of BoNT-A and 10 ml of normal saline. Each patient was evaluated for surgical and post-operative complications and followed with Disabilities of the Arm, Shoulder and Hand (DASH) Disability Scores. RESULTS: The cohort was exclusively male, 14/14 (100%). The mean age at procedure was 52.1 years (range: 29-65 years). Types of injuries repaired included: 12 acute biceps tendon ruptures, one chronic partial (> 50% of tendon) biceps tear, and two chronic biceps ruptures. Average final follow-up was 32.9 months (SD: 19.6; range: 7.07-61.72). Average time to repair of chronic injury was 5.75 months (range: 2-12 months). There were no intraoperative complications, and all patients were discharged home on the day of surgery. Average DASH score at latest follow-up was 4.9 (range: 0.0-12.5). All patients had return of function of paralyzed muscle prior to final follow-up. One patient required an incision and drainage for a deep infection 1 week post-operatively, without any further complications. Another patient required operative removal of heterotopic ossification located around the tendon fixation site, which was the result of a superficial infection treated with antibiotics 2 weeks post-operatively. This patient later healed with improvement in supination/pronation range-of-motion and no further complications. CONCLUSIONS: Injection of BoNT-A is safe and effective to protect distal biceps tendon repair during the early phases of bone-tendon healing. CLINICAL RELEVANCE: BoNT-A may is safe and effective to protect distal biceps tendon repair. The utility of BoNT-A as an adjunct to surgical repair may be applicable to acute or chronic tears as well as repairs in the non-compliant patient without decreases in functional scores after return of function of the biceps muscle. LEVEL OF EVIDENCE: Level 4.

Phaeohyphomycosis fungal infections in solid organ transplant recipients: clinical presentation, pathology, and treatment.

BACKGROUND: Dematiaceous, or dark-pigmented, fungi are known to cause infections such as phaeohyphomycosis, chromoblastomycosis, and mycetoma. These fungi are becoming increasingly important opportunistic pathogens in solid organ transplant recipients (SOTR). We present a retrospective chart review of 27 SOTR who developed phaeohyphomycosis infections post transplant from 1988 to 2009. METHODS: Cases were reviewed for fungal species isolated, date and source of culture, immunosuppressive and fungal therapy used, and outcome. The majority of isolates obtained were from the skin and soft tissue, with 3 pulmonary and brain abscesses. RESULTS: The time from transplantation to onset of infection ranged from 2 months to 11 years. The species isolated were Exophiala (11), Ochroconis (3), Alternaria (2), Phoma (2), Wangiella (1), Cladosporium (1), Aureobasidium (1), Chaetomium (1), Coniothyrium (1), and non-sporulating fungi (2). An additional 4 patients had infections confirmed by pathology, but no cultures were done. Most of the affected skin lesions were surgically debrided and treated with itraconazole; 2 patients were treated with voriconazole and 2 with amphotericin D. Death from fungal disease occurred only in patients with pulmonary and brain abscesses. CONCLUSIONS: As the number of SOTR increases, so does the incidence of fungal infections in that population. Surgery, along with antifungal therapy and a reduction in immunosuppression, are the cornerstones of treatment.

Hospitalizations for fungal infections after renal transplantation in the United States.

Fungal infections in renal transplant recipients have not been studied in a national population. Therefore, 33,420 renal transplant recipients in the United States Renal Data System from 1 July 1994 to 30 June 1997 were analyzed in a retrospective registry study of hospitalized fungal infections (FI). FI were most commonly associated with secondary diagnoses of esophagitis (68, 23.9%), pneumonia (57, 19.8%), meningitis (23, 7.6%), and urinary tract infection (29, 10.3%). Opportunistic organisms accounted for 95.4% of infections, led by candidiasis, aspergillosis, cryptococcosis, and zygomycosis. Most fungal infections (66%) had occurred by six months post-transplant, but only 22% by two months. In logistic regression analysis, end-stage renal disease due to diabetes, duration of pre-transplant dialysis, maintenance tacrolimus and allograft rejection were associated with FI. In Cox regression analysis, recipients with FI had a relative risk of mortality of 2.88 (95% CI=2.22-3.74) compared to all other recipients. Among FI, zygomycosis and aspergillosis were independently associated with both increased patient mortality and length of hospital stay. Most fungal infections in renal transplant recipients were opportunistic, occurred later than previously reported, and were associated with greatly decreased patient survival. Recipients with diabetes, prolonged pre-transplant dialysis, rejection, and tacrolimus immunosuppression should be considered high risk for FI.

Rapid DNA fingerprinting of pathogens by flow cytometry.

BACKGROUND: A new method for rapid discrimination among bacterial strains based on DNA fragment sizing by flow cytometry is presented. This revolutionary approach combines the reproducibility and reliability of restriction fragment length polymorphism (RFLP) analysis with the speed and sensitivity of flow cytometry. METHODS: Bacterial genomic DNA was isolated and digested with a rare-cutting restriction endonuclease. The resulting fragments were stained stoichiometrically with PicoGreen dye and introduced into an ultrasensitive flow cytometer. A histogram of burst sizes from the restriction fragments (linearly related to fragment length in base pairs) resulted in a DNA fingerprint that was used to distinguish among different bacterial strains. RESULTS: Five different strains of gram-negative Escherichia coli and six different strains of gram-positive Staphylococcus aureus were distinguished by analyzing their restriction fragments with DNA fragment sizing by flow cytometry. Fragment distribution analyses of extracted DNA were approximately 100 times faster and approximately 200,000 times more sensitive than pulsed-field gel electrophoresis (PFGE). When sample preparation time is included, the total DNA fragment analysis time was approximately 8 h by flow cytometry and approximately 24 h by PFGE. CONCLUSIONS: DNA fragment sizing by flow cytometry is a fast and reliable technique that can be applied to the discrimination among species and strains of human pathogens. Unlike some polymerase chain reaction (PCR)-based methods, sequence information about the bacterial strains is not required, allowing the detection of unknown, newly emerged, or unanticipated strains.

Flow cytometry-based minisequencing: a new platform for high-throughput single-nucleotide polymorphism scoring.

Single-nucleotide polymorphisms (SNPs) are the most abundant type of human genetic variation. These variable sites are present at high density in the genome, making them powerful tools for mapping and diagnosing disease-related alleles. We have developed a sensitive and rapid flow cytometry-based assay for the multiplexed analysis of SNPs based on polymerase-mediated primer extension, or minisequencing, using microspheres as solid supports. The new method involves subnanomolar concentrations of sample in small volumes ( approximately 10 microl) which can be analyzed at rates of one sample per minute or faster, without a wash step. Further, genomic analysis using multiplexing microsphere arrays (GAMMArrays), enables the simultaneous analysis of dozens, and potentially hundreds of SNPs per sample. We have tested the new method by genotyping the Glu69 variant from the HLA DPB1 locus, a SNP associated with chronic beryllium disease, as well as HLA DPA1 alleles using the multiplexed method. The results demonstrate the sensitivity and accuracy of flow cytometry-based minisequencing, a powerful new tool for genome- and global-scale SNP analysis.

High-throughput flow cytometric DNA fragment sizing.

The rate of detection and sizing of individual fluorescently labeled DNA fragments in conventional single-molecule flow cytometry (SMFC) is limited by optical saturation, photon-counting statistics, and fragment overlap to approximately 100 fragments/s. We have increased the detection rate for DNA fragment sizing in SMFC to approximately 2000 fragments/s by parallel imaging of the fluorescence from individual DNA molecules, stained with a fluorescent intercalating dye, as they passed through a planar sheet of excitation laser light, resulting in order of magnitude improvements in the measurement speed and the sample throughput compared to conventional SMFC. Fluorescence bursts were measured from a fM solution of DNA fragments ranging in size from 7 to 154 kilobase pairs. A data acquisition time of only a few seconds was sufficient to determine the DNA fragment size distribution. A linear relationship between the number of detected photons per burst and the DNA fragment size was confirmed. Application of this parallel fluorescence imaging method will lead to improvements in the speed, throughput, and sensitivity of other types of flow-based analyses involving the study of single molecules, chromosomes, cells, etc.

Effects of fluorescence excitation geometry on the accuracy of DNA fragment sizing by flow cytometry.

We report on various excitation geometries used in ultrasensitive flow cytometry that yield a linear relation between the fluorescence intensity measured from individual stained DNA fragments and the lengths of the fragments (in base pairs). This linearity holds for DNA samples that exhibit a wide range of conformations. The variety of DNA conformations leads to a distribution of dipole moment orientations for the dye molecules intercalated into the DNA. It is consequently important to use an excitation geometry such that all dye molecules are detected with similar efficiency. To estimate the conformation and the extent of elongation of the stained fragments in the flow, fluorescence polarization anisotropy and autocorrelation measurements were performed. Significant extension was observed for DNA fragments under the flow conditions frequently used for DNA fragment sizing. Classical calculations of the fluorescence emission collected over a finite solid angle are in agreement with the experimental measurements and have confirmed the relative insensitivity to DNA conformation of an orthogonal excitation geometry. Furthermore, the calculations suggested a modified excitation geometry that has increased our sizing resolution.

Bacteria genome fingerprinting by flow cytometry.

BACKGROUND: A flow cytometry-based, ultrasensitive fluorescence detection technique has been developed that demonstrates unique advantages in the analysis of large DNA fragments over the currently most widely used technology, pulsed-field gel electrophoresis (PFGE). The technique described herein is used to characterize the restriction fingerprints of the bacteria genome Staphylococcus aureus in this study. METHODS: The isolation of the bacterial genomic DNA and the subsequent complete digestion by a restriction endonuclease were performed inside an agarose plug. Electroelution was used to move the DNA fragments out-of the agarose plug into a solution containing low concentrations of spermine and spermidine, added to stabilize the large DNA fragments. DNA was stained with the bisintercalating dye thiazole orange homodimer (TOTO-1) and subsequently introduced into our ultrasensitive flow cytometer from a capillary. RESULTS: Individual DNA fragments up to 351 kbp were successfully handled and sized. The histograms of the burst sizes were generated from signals associated with individual fragments in <7 min with <2 pg of DNA. The sizing accuracy was better than 98%. In contrast, standard PFGE takes approximately 20 h and requires approximately 1 microg of DNA with a sizing accuracy of approximately 90%. CONCLUSIONS: With the demonstrated success and advantages, our approach has the potential of being applied to fast, accurate bacteria species and strain identification.

Bacterial fingerprinting by flow cytometry: bacterial species discrimination.

BACKGROUND: A flow cytometric measurement (FCM) technique has been developed to size DNA fragments. Individual fragments of a restriction digest of genomic DNA, stained with an intercalating dye, are passed through an ultrasensitive cytometer. The measured fluorescence intensity from each fragment is proportional to the fragment length. METHODS: The isolation of bacterial genomic DNA and digestion by restriction enzymes were performed inside an agarose plug. Rare cutting enzymes were employed to produce a manageable number of DNA fragments. Electroelution was used to move the DNA fragments from the agarose plug into a solution containing polyamines to protect the DNA from shear-induced breakage. The DNA was stained with the bisintercalating dye thiazole orange homodimer and introduced into our ultrasensitive flow cytometer. A histogram of the fluorescence intensities (fingerprint) was constructed. RESULTS: Gram-positive Bacillus globigii and gram-negative bacteria Escherichia coli and Erwinia herbicola were distinguished by the fingerprint pattern of restriction fragments of their genomic DNA. DNA sizes determined by FCM are in good agreement with pulsed-field gel electrophoresis (PFGE) analysis. Flow cytometry requires only picogram quantities of purified DNA and takes less than 10 min for data collection and analysis. When the total sample preparation time is included, the analysis times for PFGE and FCM are similar ( approximately 3 days). CONCLUSIONS: FCM is an attractive technique for the identification of bacterial species. It is more sensitive and potentially much faster than PFGE.

The dermatologist in military operations.

The military dermatologist has a specific and significant role in military operations--in time of war as well as in peace. Many dermatologists are unfamiliar with the impact that our specialty and cutaneous disease has upon the ability of the military to fulfill the missions, duties, and responsibilities assigned by our government. This article highlights a few of the recent or ongoing types of military operations in which our specialty plays a prominent part.

Characteristics of different nucleic acid staining dyes for DNA fragment sizing by flow cytometry.

An efficient and reliable double-stranded DNA (dsDNA) staining protocol for DNA fragment sizing by flow cytometry is presented. The protocol employs 0.8 microM of PicoGreen to label a wide range of DNA concentrations (0.5 ng/mL to 10,000 ng/mL) without regard to the solution dye/bp ratios and without initial quantification of the DNA analyte concentration. Using a combination of spectrofluorometry and flow cytometry experiments, we found that PicoGreen exhibited better overall performance than all the tested dsDNA binding dyes, such as TOTO-1. Fluorometric titration revealed that typical DNA staining protocols designed on the basis of the dye/bp ratio were highly dependent upon the DNA concentration for optimal results. PicoGreen was the least sensitive to the solution dye/bp ratio and was highly fluorescent in the presence of dsDNA. Using this new protocol, accurate histograms of HindIII digested lambda DNA were demonstrated for DNA concentrations ranging from 5 to 2000 ng/mL, and for dye/bp ratios from 106:1 to 1:4 at 0.8 microM of PicoGreen. The new one-step protocol is broadly applicable to any sensitive, laser-induced fluorescence method for detection of nucleic acids.

Efficient detection of single DNA fragments in flowing sample streams by two-photon fluorescence excitation.

This paper reports the demonstration of efficient single molecule detection in flow cytometry by two-photon fluorescence excitation. We have used two-photon excitation (TPE) to detect single DNA fragments as small as 383 base pairs (bp) labeled with the intercalating dye, POPO-1, at a dye:nucleotide ratio of 1:5. TPE of the dye-DNA complexes was accomplished using a mode-locked, 120 fs pulse width Ti:sapphire laser operating at 810 nm. POPO-1 labeled DNA fragments of 1.1 kilobase pairs (kbp) and larger were sequentially detected in our flow cytometry system with a detection efficiency of nearly 100%. The detection efficiency for the 383 bp DNA fragments was approximately 75%. We also demonstrate the ability to distinguish between different sized DNA fragments in a mixture by their individual fluorescence burst sizes by TPE. These studies indicate that using TPE for single molecule flow cytometry experiments lowers the intensity of the background radiation by approximately an order of magnitude compared to one-photon excitation, due to the large separation between the excitation and emission wavelengths in TPE.

Detection system for reaction-rate analysis in a low-volume proteinase-inhibition assay.

High-throughput screening of large combinatorial chemical libraries in biochemical assays will benefit from reduced reagent volume and increased speed of measurement. Standard assays typically are performed in 96-well microtiter plates having 200-microL well volumes and up to an hour of incubation time. In this paper, we demonstrate a technique for precise and rapid measurement of the progress of an enzymatic reaction and its inhibition with reduced volume and time (for this work, the assay was mixed at the 200-microL level and detected in 2-microL volumes with minutes of total assay time). Directly measuring the enzyme activity in the small volume format yields a precise value for the median inhibitory concentration (IC50) of an inhibitor compound. The model assay is the endoproteolytic cleavage of a small fluorogenic peptide by human neutrophil collagenase (MMP-8). The fluorogenic peptide was labeled at one end with a UV/blue fluorophore (N-methylanthranilyl) and at the other end with a quencher (dinitrophenol). To generate inhibition data, a hydroxamate peptide analog inhibitor of collagenase, actinonin, was included in the reaction. The experiments were performed using ultraviolet laser illumination (325 nm wavelength) and parallel fluorescence detection by a cooled, charge-coupled-device camera system to increase sensitivity and speed. The assay volume was reduced to 2 microL for data collection, and the total time for mixing, incubation, and measurement was less than 6 min. For comparison to a standard format, the same assay was performed in a 96-well microtiter plate in 200 microL using 30 min of incubation and measurement in a microtiter plate fluorimeter. Median inhibitory concentrations (IC50) for actinonin of 73 +/- 16 and 100 +/- 14 nM were obtained in the 2- and 200-microL assays, respectively. One concern with assay miniaturization and increases in throughput is a potential loss of precision and accuracy. Laser excitation and parallel detection of fluorescence is a promising approach for increased speed and reduced cost without loss of precision for proteinase inhibition assays.

Fluorescence correlation spectroscopy for rapid multicomponent analysis in a capillary electrophoresis system.

We describe a new technique for performing multicomponent analysis using a combination of capillary electrophoresis (CE) and fluorescence correlation spectroscopy (FCS), which we refer to as CE/FCS. FCS is a highly sensitive and rapid optical technique that is often used to perform multicomponent analysis in static solutions based on the different diffusion times of the analyte species through the detection region of a tightly focused laser beam. In CE/FCS, transit times are measured for a mixture of analytes continuously flowing through a microcapillary in the presence of an electric field. Application of an electric field between the inlet and outlet of the capillary alters the transit times, depending on the magnitude and polarity of the applied field and the electrophoretic mobilities of the analytes. Multicomponent analysis is accomplished without the need to perform a chemical separation, due to the different electrophoretic mobilities of the analytes. This technique is particularly applicable to ultradilute solutions of analyte. We have used CE/FCS to analyze subnanomolar aqueous solutions containing mixtures of Rhodamine 6G (R6G) and R6G-labeled deoxycytosine triphosphate nucleotides. Under these conditions, fewer than two molecules were typically present in the detection region at a time. The relative concentrations of the analytes were determined with uncertainties of ∼10%. Like diffusional FCS, this technique is highly sensitive and rapid. Concentration detection limits are below 10(-)(11) M, and analysis times are tens of seconds or less. However, CE/FCS does not require the diffusion coefficients of the analytes to be significantly different and can, therefore, be applied to multicomponent analysis of systems that would be difficult or impossible to study by diffusional FCS.

Single-molecule identification in flowing sample streams by fluorescence burst size and intraburst fluorescence decay rate.

We report a multiplex technique for identification of single fluorescent molecules in a flowing sample stream by correlated measurement of single-molecule fluorescence burst size and intraburst fluorescence decay rate. These quantities were measured simultaneously for single fluorescent molecules in a flowing sample stream containing a dilute mixture of fluorescent species: Rhodamine 6G and tetramethylrhodamine isothiocyanate. Using a detailed Monte Carlo simulation of our experiment, we calculate single-molecule detection efficiencies and confidence levels for identification of these species and identify major sources of error for single-molecule identification. The technique reported here is applicable to distinguishing between fluorophores with similar spectroscopic properties and requires only a single excitation wavelength and single fluorescence emission detection channel.

Rickettsialpox-like illness in a traveler.

A patient presented after a trip to South Africa with a febrile illness and rash that was consistent with either rickettsialpox or mild boutonneuse fever. The clinical, laboratory, and geographic overlap of these diseases makes differentiation difficult in certain situations. Several different rickettsial infections may cause an eschar and a rash that may be papulovesicular. From a clinical perspective, distinguishing these diseases is not critically important as long as therapy with tetracycline is implemented. More precise identification of the etiologic agent could be required in certain military situations because the preventive measures employed for some of these diseases may be significantly different.