Search

Purpose To determine whether platelet-rich plasma (PRP) injection for lateral epicondylitis offers patients comparable outcomes to lateral epicondylar surgery. Methods Embase, Cochrane Library, and MEDLINE databases were searched using the terms lateral epicondylitis, lateral elbow pain, tennis elbow, lateral epicondylalgia, and elbow tendinopathy individually and combined with the terms platelet-rich plasma injections and lateral epicondylar surgery. We compared pain relief, function between the 2 treatment options, and identified whether PRP injection reduced the incidence of lateral epicondylar surgery. Studies must have compared PRP injections with lateral epicondylar surgery for the treatment of lateral epicondylitis; be of Level I, II, or III evidence; and be written in the English language. Results Three studies (1 Level II and 2 Level III) met inclusion criteria. Two of the studies suggested that PRP injections offer similar relief as surgery in the short and mid-term, one study reported that PRP injections and surgery had similar outcomes in pain improvement and return to work, whereas 1 study reported that surgery may be a better long-term solution. Conclusions In comparison with lateral epicondylar surgery, PRP injections offer similar improvements in pain and function for patients suffering from lateral epicondylitis, especially in the short- and mid-term in 2 of the 3 included investigations. Therefore, PRP injections are an appropriate alternative for the treatment of lateral epicondylitis. Level of Evidence Level III, Systematic Review of Level III or greater evidence.

We sought to determine which demographic characteristics influence energy drink consumption habits and to examine whether caffeine content and knowledge of human nutrition affect college students' decisions to consume these beverages. We used an online survey to ask 265 college students, who did not participate in a varsity sport, to complete a survey consisting of demographic questions, the General Knowledge Questionnaire for adults, and questions about energy drink consumption habits. We found, overall, that 23.1% of our sample used energy drinks. When compared to non-consumers (76.9%), users had a significantly lower GPA, were older, and preferred drinks with a higher caffeine content. Users reported that they consumed these drinks because they wanted to feel more alert and they enjoyed the taste, even though they reported adverse effects such as trouble sleeping, shaking and tremors, and stomachaches. Knowledge of human nutrition did not affect users' choice to consume these drinks. Although the majority of college students do not consume energy drinks, room for improvement remains to curb the use of these caffeinated beverages amongst college students.

Formative assessment has been proven to be highly effective in improving student understanding. Nevertheless, many instructors struggle to engage in this practice, particularly when working in large-enrollment classrooms. To facilitate and foster the implementation of formative assessment in chemistry courses, undergraduate students at our institution have been trained to gather and analyze formative assessment data in real time in different classrooms. These “Learning Researchers” generate written reports that instructors use to inform their practice. In this article, we characterize what learning researchers involved in this project tended to notice in their observations and the nature of the interpretations that they built. The findings of our qualitative study provide insights into the affordances and potential constraints of using undergraduate students to collect and interpret formative assessment data to inform instructional practices in large-classroom environments.

PURPOSE OF REVIEW: Rates of obesity and reverse total shoulder arthroplasty (rTSA) in the USA have both escalated with time. Obese patients experience arthritis at higher rates than normal weight patients; therefore, these numbers go hand in hand. Obesity has been correlated with health comorbidities such as anxiety, cardiovascular disease, diabetes, and metabolic syndrome as well as poorer outcomes and higher complication rates following lower extremity arthroplasty. The current review investigates these comorbidities as they relate to obese patients undergoing rTSA. RECENT FINDINGS: Functional outcomes are similar to normal weight counterparts. Although longer operative times and a large soft tissue envelope would intuitively predispose these patients to higher risk for infection or other complications, this has not been reliably demonstrated. Technical considerations and awareness of potential risks in the obese patient demographic may aid the surgeon in preoperative planning and counseling of their patient. SUMMARY: Obese patients undergoing rTSA have been shown to have higher risks specifically for infection, revision, and medical complications; however, this has not been consistently demonstrated in the single surgeon series where, more often, no difference in these metrics has been found. Outcomes measures and satisfaction are reliably improved, even when considering superobese patients, and majority of studies find their improvements and absolute values to be in line with their normal weight counterparts. Thus, rTSA does not seem to carry the same level of adverse risk associated with lower joint arthroplasty but potential for higher risk still bears consideration when counseling obese patients. Attention to factors that may negatively affect prosthesis positioning may optimize retention rates and limit early failure.

To instill quality in published clinical research, reporting guidelines, consisting of checklists and flowcharts, were developed to protect against reporting poorly designed research, and researchers should be aware of the available instruments and their appropriate use. With the popularity of synthetic reviews, meta-analyses, and systematic reviews, there is a greater need to assess risk of bias and study quality. This review highlights the most frequently used guidelines and checklists, risk-of-bias scales, and quality rating scales that can assist researchers with improving their research and its eventual publication.

A nuanced approach to treatment of anterior shoulder instability is encouraged, particularly in patients with subcritical glenoid bone loss. In patients with bone loss, recurrent instability after isolated arthroscopic Bankart repair has dampened enthusiasm for this procedure. Adjunctive treatment with remplissage or dynamic anterior stabilization via biceps tenodesis to the glenoid is an alternative to bone transfer procedures, which are effective but have higher complication rates. Dynamic anterior stabilization or tenodesis of the long head of the biceps to the 3-o'clock position on the glenoid through a subscapularis split is biomechanically superior to isolated Bankart repair for reducing anterior translation, even in the setting of minor glenoid bone loss due to a sling effect similar to that produced by the Latarjet procedure. A disadvantage is placement of a large implant into the small space of the anterior glenoid and creation of a soft-tissue defect in the capsule.

PURPOSE To analyze minimum 2-year postoperative patient-reported outcomes of a large group of patients after arthroscopic subscapularis (SSc) repair with respect to surgical findings and concurrent procedures. METHODS Patients who underwent arthroscopic SSc repair from January 2010 to April 2016 completed the Patient-Reported Outcomes Measurement Information System for Upper Extremity (PROMIS-UE) test and postoperative visual analog scale pain score. Medical records were reviewed for the preoperative visual analog scale pain score and surgical findings. SSc tears were considered partial or complete. Concomitant pathology and treatment of the supraspinatus (SS), infraspinatus (IS), and biceps tendon were recorded. We compared preoperative variables and outcomes between isolated partial SSc repair, partial SSc with SS and/or IS repair, isolated complete SSc repair, and complete SSc with SS and/or IS repair. RESULTS One hundred forty-five shoulders were included with an average age of 62.0 ± 9.8 years and average follow-up period of 52.2 ± 19.5 months. A significant reduction in the pain score occurred, from 4.8 (95% confidence interval [CI], 4.4-5.2) to 0.9 (95% CI, 0.6-1.1) (P < .001), with a mean postoperative PROMIS-UE score of 50.7 (95% CI, 49.5-52.0). Most SSc tears were partial with SS and/or IS repair (44.1%). Isolated partial SSc tears (29.9%), complete SSc tears with SS and/or IS repair (20.1%), and isolated complete SSc tears (5.9%) were less common. A significant difference in the mean postoperative PROMIS-UE score was not found between groups (P = .609). Biceps tendon pathology was significantly more common in complete SSc tears than partial SSc tears (P < .001), but there was no difference in the rate of biceps intervention (P = .110) or the PROMIS-UE score based on biceps intervention (P = .471). CONCLUSIONS We observed significant improvements in pain and patient-reported outcomes in line with population means for a large group of patients after SSc tendon repair. Importantly, outcomes were similar despite the size of SSc tear or concurrent SS and/or IS repairs. Biceps pathology was common, and neither its presence nor its treatment influenced postoperative patient outcomes. LEVEL OF EVIDENCE Level IV, retrospective case series.

Tears of the subscapularis tendon can be challenging to diagnose and treat. Because the subscapularis plays an important role in shoulder function, careful arthroscopic evaluation and treatment are necessary to restore function. Previous surgical techniques have ranged from full open repairs to complex arthroscopic procedures needing suture passer and/or retriever devices. We describe an arthroscopic surgical technique of subscapularis repair through a single anterior portal using only penetrating graspers. This approach can be used for partial upper-border subscapularis tears, as well as complete and retracted subscapularis tendon tears., Technique Video Video 1 Right shoulder visualized from posterior portal with patient in beach-chair position.

Background:Rotator cuff fatty infiltration has been correlated with poorer radiographic and clinical outcomes in supraspinatus and infraspinatus tendon repairs, but this has not been well-studied in subscapularis tendon repairs.Purpose:To evaluate the influence of preoperative rotator cuff fatty infiltration on postoperative outcomes for patients undergoing arthroscopic subscapularis tendon repair.Study Design:Cohort study; Level of evidence, 3.Methods:Patients who underwent arthroscopic subscapularis repair between 2010 and 2016 were retrospectively identified, and demographic data and surgical findings were recorded. The extent of fatty infiltration was determined on preoperative magnetic resonance imaging by the Fuchs modification of the Goutallier classification. At the most recent follow-up, patients completed the Patient-Reported Outcomes Measurement Information System for Upper Extremity (PROMIS-UE) computer adaptive test and a postoperative visual analog scale for pain. The distribution of fatty infiltration was compared between patients undergoing subscapularis tendon repair versus subscapularis tendon repair combined with a posterior cuff repair. Outcomes were compared for patients using Goutallier grade 0-1 versus grade ≥2 changes in each rotator cuff muscle. Multivariate linear regression analysis was performed to evaluate the influence of muscle quality, as well as demographic factors, on PROMIS-UE scores. Significance was defined as P < .05.Results:There were 140 shoulders included (mean age, 61.8 years; 42.1% female; mean follow-up, 51.7 months). The prevalence of Goutallier grade 2 changes or higher was significantly greater in patients with multitendon repair relative to isolated subscapularis tendon repair. For the overall group of all patients undergoing subscapularis tendon repair, whether in isolation or as part of a multitendon repair, PROMIS-UE scores were significantly lower for patients with infraspinatus muscle grade 2 or higher Goutallier changes relative to grade 0 or 1. After adjustment for age, body mass index, patient sex, and fatty infiltration in other rotator cuff muscles, poor infraspinatus muscle quality remained the only significant predictor for lower PROMIS-UE scores.Conclusion:Patients undergoing arthroscopic subscapularis tendon repair with poor infraspinatus muscle quality had worse patient-reported outcomes. This was true whether subscapularis tendon repair was isolated or was performed in conjunction with supraspinatus and infraspinatus tendon repairs.

Genome sequencing of microorganisms has revealed a greatly increased capacity for natural products biosynthesis than was previously recognized from compound isolation efforts alone. Hence, new methods are needed for the discovery and description of this hidden secondary metabolite potential. Here we show that provision of heavy nitrogen 15N-nitrate to marine cyanobacterial cultures followed by single filament MALDI analysis over a period of days was highly effective in identifying a new natural product with an exceptionally high nitrogen content. The compound, named cryptomaldamide, was subsequently isolated using MS to guide the purification process, and its structure determined by 2D NMR and other spectroscopic and chromatographic methods. Bioinformatic analysis of the draft genome sequence identified a 28.7 kB gene cluster which putatively encodes for cryptomaldamide biosynthesis. Notably, an amidinotransferase is proposed to initiate the biosynthetic process by transferring an amidino group from arginine to serine to produce the first residue to be incorporated by the hybrid NRPS-PKS pathway. The maldiisotopic approach presented here is thus demonstrated to provide an orthogonal method by which to discover novel chemical diversity from Nature.

Cyanobacteria are major sources of oxygen, nitrogen, and carbon in nature. In addition to the importance of their primary metabolism, some cyanobacteria are prolific producers of unique and bioactive secondary metabolites. Chemical investigations of the cyanobacterial genus Moorea have resulted in the isolation of over 190 compounds in the last two decades. However, preliminary genomic analysis has suggested that genome-guided approaches can enable the discovery of novel compounds from even well-studied Moorea strains, highlighting the importance of obtaining complete genomes. We report a complete genome of a filamentous tropical marine cyanobacterium, Moorea producens PAL, which reveals that about one-fifth of its genome is devoted to production of secondary metabolites, an impressive four times the cyanobacterial average. Moreover, possession of the complete PAL genome has allowed improvement to the assembly of three other Moorea draft genomes. Comparative genomics revealed that they are remarkably similar to one another, despite their differences in geography, morphology, and secondary metabolite profiles. Gene cluster networking highlights that this genus is distinctive among cyanobacteria, not only in the number of secondary metabolite pathways but also in the content of many pathways, which are potentially distinct from all other bacterial gene clusters to date. These findings portend that future genome-guided secondary metabolite discovery and isolation efforts should be highly productive.

BACKGROUND Partial transphyseal anterior cruciate ligament (ACL) reconstruction is a technique utilized in the skeletally immature population. The femoral tunnel is placed in the distal femoral epiphysis whereas the tibial tunnel is placed in a transphyseal fashion medial to the tibial tubercle. This technique was introduced in an effort to lessen insult to the distal femoral physis of skeletally immature adolescents while also avoiding the technical difficulty of placing an intra-epiphyseal tunnel in the proximal tibia which at times can be non-anatomic. There is limited literature examining this technique. In this study we analyzed the concurrent surgical procedures, re-operation and graft failure rates, and radiographic outcomes in adolescents undergoing partial transphyseal ACL reconstruction. METHODS Consecutive patients undergoing partial transphyseal ACL reconstruction by the two senior authors (NP and CA) were retrospectively reviewed. Inclusion criteria consisted of patients with symptomatic ACL rupture with open distal femoral physes and at least two years of growth remaining by chronologic and physiologic age as determined by growth and pubertal history. All patients received hamstring autograft. Femoral tunnels were drilled in an intra-epiphyseal location utilizing small angle guides under fluoroscopic guidance. Transphyseal tibial tunnels were drilled in standard fashion with a tip-aiming guide while minimizing thermal damage from slow reaming, avoiding horizontal tunnel placement, and using extraphyseal graft fixation to lessen insult to the proximal tibial physis. Radiographic outcomes including bilateral limb length (LL) and alignment as judged by mechanical axis deviation (MAD), mechanical lateral distal femoral angle (mLDFA), and medial proximal tibial angle (MPTA) were measured on long standing anterior-to-posterior (AP) view radiographs. Growth disturbance was defined as = 1 cm leg length discrepancy, = 1 cm difference in MAD, or 5-degree difference in mLDFA or MPTA as compared to the non-operative side and MAD/mLDFA/MPTA outside of established range of normal values. Clinical outcomes including graft failure and need for repeat operation were recorded at each follow-up visit. Operative extremity alignment measurements were compared to non-operative extremity measurements utilizing a paired students t-test. RESULTS Twenty-four patients with average follow up of 31.5 ± 17.1 months met inclusion criteria for this study. Five female and 19 male patients were enrolled consisting of 13 left and 11 right knees. Average age at time of surgery was 12.3 ± 0.9 years (10.1-13.8 years). The average ACL graft size was 7.8 mm ± 0.5 mm (6-9 mm). Ten patients (41.7%) had concurrent meniscal surgery, with seven (29.2%) undergoing partial lateral meniscectomy, two (8.3%) lateral meniscus repairs, and one patient (4.2%) with medial and lateral meniscal repairs. Six patients (25.0%) required re-operation at an average of 29.2 ± 17.3 months (1.5-49.5 months) for removal of hardware (n=3), revision ACL reconstruction (n=2), and meniscus surgery (n=1). Two patients had ACL graft failure (8.3%) during sporting activity and underwent revision ACL reconstruction at 19.7 months and 49.5 months post-operatively. There were no contralateral ACL tears. As shown in Table 1, comparison of the mean alignment and limb length measurements between all patients’ operative to nonoperative extremity revealed no significant difference in femur length, MAD, MLDFA, or MPTA. There was a small but statistically significant difference in operative versus non-operative tibia length (390.2 cm versus 392.4 cm, p=0.0004) and limb length (880.9 cm versus 884.0 cm, p=0.02). In analyzing individual patients’ limb length or alignment differences, five patients (20.8%) were identified with a growth disturbance. One patient had isolated shortening of the operative extremity, two with significant lateral deviation of the MAD, and two with both shortening and lateral MAD translation. No patients had significant side-to-side difference in mLDFA or MPTA. Femoral shortening accounted for the majority of the limb length discrepancy in two of the three patients with significant limb length discrepancy. All patients returned to sport. CONCLUSIONS / SIGNIFICANCE Partial transphyseal ACL reconstruction has a 25.0% re-operation rate, most often for hardware removal, and an 8.3% graft failure rate. Overall, approximately 20% of patients undergoing partial transphyseal ACL reconstruction had a growth disturbance but none required surgical intervention for these disturbances. While the partial transphyseal technique spares the distal femoral physis, femur-dominant limb length discrepancy can still occur. Drilling and graft placement across the tibial physis appears to be safe. Further studies are needed to directly compare the radiographic, functional, and clinical outcomes of partial transphyseal ACL reconstruction with transphyseal and all-epiphyseal techniques in the pediatric population. [Table: see text]

Background American medical schools have gradually achieved balance in the sex of medical graduates over the past 4 decades. However, orthopaedic surgery has remained disproportionately male-dominated. Our aim was to quantify this discrepancy across surgical specialties at the residency training and academic faculty levels. We additionally sought to evaluate the prevalence of women in orthopaedic subspecialty and research societies. Methods Publicly available data from the Association of American Medical Colleges (AAMC) and the Accreditation Council for Graduate Medical Education (ACGME) for the 2005-2006 to 2016-2017 academic years were pooled for analysis of sex in surgical residency programs. The AAMC 2016 Faculty Roster provided data on the sex composition of academic medical faculty, including rank. Current subspecialty and research society membership demographic characteristics were obtained by directly contacting each group. Results Female orthopaedic surgery residents represented 0.92% of all female medical residents in the 2016-2017 academic year. Orthopaedic surgery remains the medical specialty with the lowest proportion of female residents at 14.0% in the 2016-2017 academic year, up from 11.0% in the 2005-2006 academic year. The percentage increase over this time period (27.3%) lags behind other male-dominated fields such as neurological surgery (56.8%) and thoracic surgery (111.2%). Women account for 17.8% of full-time orthopaedic surgery faculty at American medical schools, lower than all other medical specialties. In the 2015-2016 academic year, 1 orthopaedic surgery department chair and only 8.7% of professors of orthopaedic surgery were female. Women make up 6.5% of the American Academy of Orthopaedic Surgeons (AAOS) membership. The specialty societies with the fewest women are The Knee Society (0.5%), The Hip Society (0.6%), and the Cervical Spine Research Society (1.5%). Conclusions Orthopaedic surgery's slow increase in the number of female residents and academic faculty lags behind that of other specialties. The lack of female orthopaedic surgeons in higher ranks within medical schools is detrimental to recruitment of female medical students to the field. Further efforts should be made toward increasing medical student exposure to orthopaedics and to female mentors in an effort to ensure that the field continues to attract the nation's top medical graduates.

Hip arthroscopy has become the standard treatment for symptomatic femoroacetabular impingement as patients have shown good outcomes and high satisfaction with this intervention. However, capsular management to gain access for intra-articular procedures remains greatly debated. Capsular closure is advocated particularly in the setting of interportal or T-capsulotomy to avoid complications of instability or nonhealing capsule. We introduce a technique for capsular management through a limited periportal capsulotomy during arthroscopic treatment of femoroacetabular impingement. In using dilation of the anterolateral and mid-anterior portals without completion of a full interportal capsulotomy, the stabilizing iliofemoral ligament is preserved. We have found that periportal capsulotomy provides safe and sufficient access to the hip joint without necessitating capsular closure.

Purpose To present the technique and outcomes of a limited periportal capsulotomy without capsular closure for arthroscopic treatment of femoroacetabular impingement (FAI). Methods Retrospective review of a prospectively collected database of patients undergoing primary hip arthroscopy for symptomatic FAI was performed to analyze patients who underwent periportal capsulotomy. Periportal capsulotomy was performed through dilation of the midanterior and anterolateral portals without completion of a full interportal capsulotomy, preserving the iliofemoral ligament. Arthroscopic labral treatment and osteochondroplasty were completed as indicated without necessitating capsular closure. Patient demographics, surgical details, and complications were recorded. Pre- and postoperatively, patients completed the modified Harris Hip Score, Hip Disability and Osteoarthritis Outcome Score (HOOS), 12-item Short-Form survey, and visual analog scale. Postoperative outcome data was analyzed at 1- and 2-year follow-up. Results One hundred and forty-two patients treated with the periportal capsulotomy technique were included (mean age, 35.5 ± 11.7; body mass index, 25.4 ± 4.1; 50.7% men). There were no major postoperative complications including hip instability or reoperation. Significant improvements in mean patient-reported outcomes from preoperative scores were seen at the 1- and 2-year follow-ups (modified Harris Hip Score, 18.4 ± 19.1, 21.1 ±17.7, HOOS symptoms, 20.1 ± 21.2, 22.8 ± 23.5, HOOS pain, 23.4 ± 21.2, 27.6 ± 19.3, HOOS activities of daily life, 21.2 ± 20.8, 24.3 ± 21.6, HOOS sport, 32.5 ± 27.0, 36.5 ± 26.9, HOOS quality of life, 37.9 ± 26.7, 46.0 ± 22.8, and 12-item Short-Form survey physical component score, 16.4 ± 15.3, 20.8 ±13.2, respectively). Only the HOOS quality of life demonstrated further improvement from 1- to 2 years postoperatively (P = .043). Conclusions Periportal capsulotomy provides safe and sufficient access to the hip joint for arthroscopic treatment of FAI without necessitating capsular closure. Using this technique, patients showed significant clinical improvement and no postoperative instability at 1 and 2 years after surgery. Level of Evidence Level IV, therapeutic case series.

M.H.M. was supported by a Rubicon fellowship of the Netherlands Organization for Scientific Research (NWO;Rubicon 825.13.001). The work of R.K. was supported by the European Union’s Seventh Framework Programme(Joint Call OCEAN.2011–2: Marine microbial diversity—new insights into marine ecosystems functioning and its biotechnological potential) under the grant agreement no.287589 (Micro B3). M.C. was supported by a Biotechnology and Biological Sciences Research Council (BBSRC)studentship (BB/J014478/1). The GSC is supported by funding from the Natural Environment Research Council(UK), the National Institute for Energy Ethics and Society(NIEeS; UK), the Gordon and Betty Moore Foundation,the National Science Foundation (NSF; US) and the US Department of Energy. The Manchester Synthetic Biology Research Centre, SYNBIOCHEM, is supported by BBSRC/Engineering and Physical Sciences Research Council(EPSRC) grant BB/M017702/1, Medema, M.H., Kottmann, R., Yilmaz, P., Cummings, M., Biggins, J.B., Blin, K., De Bruijn, I., Chooi, Y.H., Claesen, J., Coates, R.C., Cruz-Morales, P., Duddela, S., Düsterhus, S., Edwards, D.J., Fewer, D.P., Garg, N., Geiger, C., Gomez-Escribano, J.P., Greule, A., Hadjithomas, M., Haines, A.S., Helfrich, E.J.N., Hillwig, M.L., Ishida, K., Jones, A.C., Jones, C.S., Jungmann, K., Kegler, C., Kim, H.U., Kötter, P., Krug, D., Masschelein, J., Melnik, A.V., Mantovani, S.M., Monroe, E.A., Moore, M., Moss, N., Nützmann, H.-W., Pan, G., Pati, A., Petras, D., Reen, F.J., Rosconi, F., Rui, Z., Tian, Z., Tobias, N.J., Tsunematsu, Y., Wiemann, P., Wyckoff, E., Yan, X., Yim, G., Yu, F., Xie, Y., Aigle, B., Apel, A.K., Balibar, C.J., Balskus, E.P., Barona-Gómez, F., Bechthold, A., Bode, H.B., Borriss, R., Brady, S.F., Brakhage, A.A., Caffrey, P., Cheng, Y.Q., Clardy, J., Cox, R.J., De Mot, R., Donadio, S., Donia, M.S., Van Der Donk, W.A., Dorrestein, P.C., Doyle, S., Driessen, A.J.M., Ehling-Schulz, M., Entian, K.-D., Fischbach, M.A., Gerwick, L., Gerwick, W.H., Gross, H., Gust, B., Hertweck, C., Höfte, M., Jensen, S.E., Ju, J., Katz, L., Kaysser, L., Klassen, J.L., Keller, N.P., Kormanec, J., Kuipers, O.P., Kuzuyama, T., Kyrpides, N.C., Kwon, H.-J., Lautru, S., Lavigne, R., Lee, C.Y., Linquan, B., Liu, X., Liu, W., Luzhetskyy, A., Mahmud, T., Mast, Y., Méndez, C., Metsä-Ketelä, M., Micklefield, J., Mitchell, D.A., Moore, B.S., Moreira, L.M., Müller, R., Neilan, B.A., Nett, M., Nielsen, J., O'Gara, F., Oikawa, H., Osbourn, A., Osburne, M.S., Ostash, B., Payne, S.M., Pernodet, J.-L., Petricek, M., Piel, J., Ploux, O., Raaijmakers, J.M., Salas, J.A., Schmitt, E.K., Scott, B., Seipke, R.F., Shen, B., Sherman, D.H., Sivonen, K., Smanski, M.J., Sosio, M., Stegmann, E., Süssmuth, R.D., Tahlan, K., Thomas, C.M., Tang, Y., Truman, A.W., Viaud, M., Walton, J.D., Walsh, C.T., Weber, T., Van Wezel, G.P., Wilkinson, B., Willey, J.M., Wohlleben, W., Wright, G.D., Ziemert, N., Zhang, C., Zotchev, S.B., Breitling, R., Takano, E., Glöckner, F.O.

An innovative approach was developed for the discovery of new natural products by combining mass spectrometric metabolic profiling with genomic analysis and resulted in the discovery of the columbamides, a new class of di- and trichlorinated acyl amides with cannabinomimetic activity. Three species of cultured marine cyanobacteria, Moorea producens 3L, Moorea producens JHB, and Moorea bouillonii PNG, were subjected to genome sequencing and analysis for their recognizable biosynthetic pathways, and this information was then compared with their respective metabolomes as detected by MS profiling. By genome analysis, a presumed regulatory domain was identified upstream of several previously described biosynthetic gene clusters in two of these cyanobacteria, M. producens 3L and M. producens JHB. A similar regulatory domain was identified in the M. bouillonii PNG genome, and a corresponding downstream biosynthetic gene cluster was located and carefully analyzed. Subsequently, MS-based molecular networking identified a series of candidate products, and these were isolated and their structures rigorously established. On the basis of their distinctive acyl amide structure, the most prevalent metabolite was evaluated for cannabinomimetic properties and found to be moderate affinity ligands for CB1.

Case Intra-articular osteoid osteoma (IAOO) is a relatively rare entity and can pose a therapeutic challenge due to proximity to the cartilage surface. We present 2 cases of subchondral osteoid osteomata within the distal femur treated with excision and osteochondral grafting of the resultant defect. Conclusions Subchondral IAOO can pose a therapeutic challenge. Our patients had an effective pain relief and return to activities with this treatment strategy.

Phormidolide is a polyketide produced by a cultured filamentous marine cyanobacterium and incorporates a 16-membered macrolactone. Its complex structure is recognizably derived from a polyketide synthase pathway, but possesses unique and intriguing structural features that prompted interest in investigating its biosynthetic origin. Stable isotope incorporation experiments confirmed the polyketide nature of this compound. We further characterized the phormidolide gene cluster (phm) through genome sequencing followed by bioinformatic analysis. Two discrete trans-type acyltransferase (trans-AT) ORFs along with KS-AT adaptor regions (ATd) within the polyketide synthase (PKS) megasynthases, suggest that the phormidolide gene cluster is a trans-AT PKS. Insights gained from analysis of the mode of acetate incorporation and ensuing keto reduction prompted our reevaluation of the stereochemistry of phormidolide hydroxy groups located along the linear polyketide chain.

Filamentous cyanobacteria of the genus Lyngbya are important contributors to coral reef ecosystems, occasionally forming dominant cover and impacting the health of many other co-occurring organisms. Moreover, they are extraordinarily rich sources of bioactive secondary metabolites, with 35% of all reported cyanobacterial natural products deriving from this single pantropical genus. However, the true natural product potential and life strategies of Lyngbya strains are poorly understood because of phylogenetic ambiguity, lack of genomic information, and their close associations with heterotrophic bacteria and other cyanobacteria. To gauge the natural product potential of Lyngbya and gain insights into potential microbial interactions, we sequenced the genome of Lyngbya majuscula 3L, a Caribbean strain that produces the tubulin polymerization inhibitor curacin A and the molluscicide barbamide, using a combination of Sanger and 454 sequencing approaches. Whereas ∼293,000 nucleotides of the draft genome are putatively dedicated to secondary metabolism, this is far too few to encode a large suite of Lyngbya metabolites, suggesting Lyngbya metabolites are strain specific and may be useful in species delineation. Our analysis revealed a complex gene regulatory network, including a large number of sigma factors and other regulatory proteins, indicating an enhanced ability for environmental adaptation or microbial associations. Although Lyngbya species are reported to fix nitrogen, nitrogenase genes were not found in the genome or by PCR of genomic DNA. Subsequent growth experiments confirmed that L. majuscula 3L is unable to fix atmospheric nitrogen. These unanticipated life history characteristics challenge current views of the genus Lyngbya .

The dinoflagellate Karenia brevis (C. C. Davis) Gert Hansen et Moestrup produces a suite of brevetoxins, potent neurotoxins that have adverse effects on marine animal and human health. Brevetoxins are polyketides proposed to be synthesized by polyketide synthases (PKSs), and genes for type I PKSs have been predicted by PCR and transcript analysis. However, the full-length transcripts in K. brevis predict an unusual protein structure for type I PKS in that individual transcripts encode for single catalytic domains. In this study, we developed peptide antibodies to in silico translated transcripts for two PKS proteins to characterize their expression and localization. Immunoreactive proteins identified by Western blotting at 40 kDa (KR domain) and 100 kDa (KS domain) are consistent with the sizes predicted by the full-length transcripts. Immunolocalization and Western blot analysis indicate that these PKSs are associated with the chloroplasts. In order to establish evidence for a role in brevetoxin biosynthesis, PKS transcript and protein levels were examined in a “nontoxic”K. brevis substrain and its parental toxic isolate, K. brevis Wilson. DNA microarray analysis of the global transcript profiles in the “nontoxic” isolate showed that ∼7% of transcripts were differentially expressed, including photosystem genes; however, no difference was observed in PKS transcript abundance. By contrast, KS domain proteins were 55%–70% less abundant in “nontoxic”K. brevis cultures compared to toxic cultures. This finding suggests that K. brevis PKS expression is regulated posttranscriptionally, like many other processes in dinoflagellates. Further, the decrease in PKS protein abundance in the “nontoxic” cultures provides correlative evidence for their involvement in brevetoxin biosynthesis.

Gulf of Mexico blooms of the dinoflagellate Karenia brevis produce neurotoxic cyclic polyethers called brevetoxins. During and after a red tide bloom in southwestern Florida, K. brevis cells lyse and release brevetoxins, which then sink to the benthos and coat the surfaces of seagrasses and their epiphytes. We tested the possibility that these brevetoxin-laden foods alter the feeding behavior and fitness of a common benthic herbivore within Floridean seagrass beds, the amphipod Ampithoe longimana. We demonstrated that coating foods with K. brevis extracts that contain brevetoxins at post-bloom concentrations (1 microg g(-1) drymass) does not alter the feeding rates of Florida nor North Carolina populations of A. longimana, although a slight deterrent effect was found at eight and ten-fold greater concentrations. During a series of feeding choice assays, A. longimana tended not to be deterred by foods coated with K. brevis extracts nor with the purified brevetoxins PbTx-2 and PbTx-3. Florida juveniles isolated with either extract-coated or control foods for 10 days did not differ in survivorship nor growth. A similar lack of feeding response to brevetoxin-laden foods also was exhibited by two other generalist herbivores of the southeastern United States, the amphipod A. valida and the urchin Arbacia punctulata. Given that benthic mesograzers constitute a significant portion of the diet for the juvenile stage of many nearshore fishes, we hypothesize that the ability of some mesograzers to feed on and retain brevetoxins in their bodies indicates that mesograzers may represent an important route of vertical transmission of brevetoxins through higher trophic levels within Gulf of Mexico estuaries.

The dinoflagellate Karenia brevis is responsible for nearly annual red tides in the Gulf of Mexico that cause extensive marine mortalities and human illness due to the production of brevetoxins. Although the mechanisms regulating its bloom dynamics and toxicity have received considerable attention, investigation into these processes at the cellular and molecular level has only begun in earnest during the past decade. This review provides an overview of the recent advances in our understanding of the cellular and molecular biology on K. brevis. Several molecular resources developed for K. brevis, including cDNA and genomic DNA libraries, DNA microarrays, metagenomic libraries, and probes for population genetics, have revolutionized our ability to investigate fundamental questions about K. brevis biology. Two cellular processes have received particular attention, the vegetative cell cycle and vertical migration behavior, which are of key importance due to their roles in the development of both surface populations that constitute blooms and subsurface cell aggregations that may serve to initiate them. High throughput sequencing of cDNA libraries has provided the first glimpse of the gene repertoire in K. brevis, with approximately 12,000 unique genes identified to date. Phylogenomic analysis of these genes has revealed a high rate of horizontal gene transfer in K. brevis, which has resulted in a chimeric chloroplast through the selective retention of genes of red, green, and haptophyte origin, whose adaptive significance is not yet clear. Gene expression studies using DNA microarrays have demonstrated a prevalence of post-transcriptional gene regulation in K. brevis and led to the discovery of an unusual spliced leader trans-splicing mechanism. Among the trans-spliced gene transcripts are type I polyketide synthases (PKSs), implicated in brevetoxin biosynthesis, which are unique among type I PKSs in that each transcript encodes an individual catalytic domain, suggesting a novel gene structure in this dinoflagellate. Clone libraries of 16S ribosomal DNA sequences developed from bloom waters have unveiled the temporal and spatial complexity of the microbial soup that coexists with K. brevis and its active involvement in both bloom growth and termination processes. Finally, the development and application of population genetic markers has revealed a surprisingly high genetic diversity in K. brevis blooms, long assumed to consist of essentially clonal populations. With these foundations in place, our understanding of K. brevis bloom dynamics is likely to grow exponentially in the next few years.

Karenia brevis is the Florida red tide dinoflagellate responsible for detrimental effects on human and environmental health through the production of brevetoxins. Brevetoxins are thought to be synthesized by a polyketide synthase (PKS) complex, but the gene cluster for this PKS has yet to be identified. Here, eight PKS transcripts were identified in K. brevis by high throughput cDNA library screening. Full length sequences were obtained through 3' and 5' RACE, which demonstrated the presence of polyadenylation, 3'-UTRs, and an identical dinoflagellate-specific spliced leader sequence at the 5' end of PKS transcripts. Six transcripts encoded for individual ketosynthase (KS) domains, one ketoreductase (KR), and one transcript encoded both acyl carrier protein (ACP) and KS domains. Transcript lengths ranged from 1875 to 3397 nucleotides, based on sequence analysis, and were confirmed by northern blotting. Baysian phylogenetic analysis of the K. brevis KS domains placed them well within the protist type I PKS clade. Thus although most similar to type I modular PKSs, the presence of individual catalytic domains on separate transcripts suggests a protein structure more similar to type II PKSs, in which each catalytic domain resides on an individual protein. These results identify an unprecedented PKS structure in a toxic dinoflagellate.

The photoperiod plays a central role in regulating the physiology and behavior of photosynthetic phytoplankton, and many of these processes are controlled by an underlying circadian rhythm. In dinoflagellates, circadian rhythms have been shown to depend largely on posttranscriptional regulation. However, the extent to which dinoflagellates modulate transcript levels to regulate gene expression in response to light and dark has not been addressed. Here we utilized an oligonucleotide microarray containing probes to 4629 unique genes from the Florida red-tide dinoflagellate Karenia brevis (C. C. Davis) G. Hansen et Moestrup to characterize global gene expression patterns over a 24 h day in cells exposed to a 16:8 light:dark cycle (LD treatment) and cells under constant light (LL treatment). We determined that 9.8% of the queried genes were differentially expressed during LD, while 3% of genes were differentially expressed over the 24 h day when exposed to LL. Most genes exhibited either peak or minimum expression in early dark phase. Of the 453 differentially expressed genes in LD, 104 were assigned predicted annotations based on BLASTX searches. Few of the identifiable genes that were differentially expressed in LD appear to be under circadian control, as their cyclical expression did not persist in LL. Analysis of coordinately expressed genes revealed several novel insights into dinoflagellate gene expression, including an unusually high representation of genes involved in post-transcriptional processing of RNA and protein turnover, the regulation of PSII genes in response to light and dark, and the absence of transcriptional regulation of cell-cycle genes.

Moorea producens JHB, a Jamaican strain of tropical filamentous marine cyanobacteria, has been extensively studied by traditional natural products techniques. These previous bioassay and structure guided isolations led to the discovery of two exciting classes of natural products, hectochlorin (1) and jamaicamides A (2) and B (3). In the current study, mass spectrometry-based 'molecular networking' was used to visualize the metabolome of Moorea producens JHB, and both guided and enhanced the isolation workflow, revealing additional metabolites in these compound classes. Further, we developed additional insight into the metabolic capabilities of this strain by genome sequencing analysis, which subsequently led to the isolation of a compound unrelated to the jamaicamide and hectochlorin families. Another approach involved stimulation of the biosynthesis of a minor jamaicamide metabolite by cultivation in modified media, and provided insights about the underlying biosynthetic machinery as well as preliminary structure-activity information within this structure class. This study demonstrated that these orthogonal approaches are complementary and enrich secondary metabolomic coverage even in an extensively studied bacterial strain.

Treatments for patellofemoral pain syndrome (PFPS) are as numerous as its potential causes. This is most likely, in part, due to its multifactorial and complex nature. Patellofemoral pain syndrome represents retropatellar and/or peripatellar pain that is usually exacerbated by activities such as sitting, kneeling, squatting, and stair climbing. The PFPS diagnosis is largely one of exclusion because many other conditions need to be ruled out first. In addition to providing an operational definition for PFPS, this chapter presents a structured rehabilitation model for its treatment based on regional symptom categorization. This categorization will enable rehabilitation clinicians to group patients with similar PFPS etiologies into the same treatment group, thereby helping develop more standardized care and stronger research evidence supporting treatment efficacy. © Springer-Verlag Berlin Heidelberg 2012, 2015, All Rights Reserved.

Background: Attritional bone loss in patients with recurrent anterior instability has successfully been treated with a bone block procedure such as the Latarjet. It has not been previously demonstrated whether cortical or cancellous screws are superior when used for this procedure. Purpose: To assess the strength of stainless steel cortical screws versus stainless steel cannulated cancellous screws in the Latarjet procedure. Study Design: Controlled laboratory study. Methods: Ten fresh-frozen matched-pair shoulder specimens were randomized into 2 separate fixation groups: (1) 3.5-mm stainless steel cortical screws and (2) 4.0-mm stainless steel partially threaded cannulated cancellous screws. Shoulder specimens were dissected free of all soft tissue and a 25% glenoid defect was created. The coracoid process was osteomized, placed at the site of the glenoid defect, and fixed in place with 2 parallel screws. Results: All 10 specimens failed by screw cutout. Nine of 10 specimens failed by progressive displacement with an increased number of cycles. One specimen in the 4.0-mm screw group failed by catastrophic failure on initiation of the testing protocol. The 3.5-mm screws had a mean of 274 cycles (SD, ±171 cycles; range, 10-443 cycles) to failure. The 4.0-mm screws had a mean of 135 cycles (SD, ±141 cycles; range, 0-284 cycles) to failure. There was no statistically significant difference between the 2 types of screws for cycles required to cause failure ( P = .144). Conclusion: There was no statistically significant difference in energy or cycles to failure when comparing the stainless steel cortical screws versus partially threaded cannulated cancellous screws. Clinical Relevance: Latarjet may be performed using cortical or cancellous screws without a clear advantage of either option.

Cyanobacteria are abundant producers of natural products well recognized for their bioactivity and utility in drug discovery and biotechnology applications. In the last decade, characterization of several modular gene clusters that code for the biosynthesis of these compounds has revealed a number of unusual enzymatic reactions. In this article, we review several mechanistic transformations identified in marine cyanobacterial biosynthetic pathways, with an emphasis on modular polyketide synthase(PKS)/non-ribosomal peptide synthetase (NRPS) gene clusters. In selected instances, we also make comparisons between cyanobacterial gene clusters derived from marine and freshwater strains. We then provide an overview of recent developments in cyanobacterial natural products biosynthesis made available through genome sequencing and new advances in bioinformatics and genetics.

Cyanobacteria are abundant producers of natural products well recognized for their bioactivity and utility in drug discovery and biotechnology applications. In the last decade, characterization of several modular gene clusters that code for the biosynthesis of these compounds has revealed a number of unusual enzymatic reactions. In this article, we review several mechanistic transformations identified in marine cyanobacterial biosynthetic pathways, with an emphasis on modular polyketide synthase(PKS)/non-ribosomal peptide synthetase (NRPS) gene clusters. In selected instances, we also make comparisons between cyanobacterial gene clusters derived from marine and freshwater strains. We then provide an overview of recent developments in cyanobacterial natural products biosynthesis made available through genome sequencing and new advances in bioinformatics and genetics.

Hormaomycin, an NRPS-produced bacterial metabolite involved in microbial signaling, possesses several remarkable structural features. The study by Höfer et al. (2011) employed a range of methodologies to explore and ultimately understand the elaborate biosynthesis of this complex natural product.

Background The role of coastal nutrient sources in the persistence of Karenia brevis red tides in coastal waters of Florida is a contentious issue that warrants investigation into the regulation of nutrient responses in this dinoflagellate. In other phytoplankton studied, nutrient status is reflected by the expression levels of N- and P-responsive gene transcripts. In dinoflagellates, however, many processes are regulated post-transcriptionally. All nuclear encoded gene transcripts studied to date possess a 5' trans-spliced leader (SL) sequence suggestive, based on the trypanosome model, of post-transcriptional regulation. The current study therefore sought to determine if the transcriptome of K. brevis is responsive to nitrogen and phosphorus and is informative of nutrient status. Results Microarray analysis of N-depleted K. brevis cultures revealed an increase in the expression of transcripts involved in N-assimilation (nitrate and ammonium transporters, glutamine synthetases) relative to nutrient replete cells. In contrast, a transcriptional signal of P-starvation was not apparent despite evidence of P-starvation based on their rapid growth response to P-addition. To study transcriptome responses to nutrient addition, the limiting nutrient was added to depleted cells and changes in global gene expression were assessed over the first 48 hours following nutrient addition. Both N- and P-addition resulted in significant changes in approximately 4% of genes on the microarray, using a significance cutoff of 1.7-fold and p ≤ 10-4. By far, the earliest responding genes were dominated in both nutrient treatments by pentatricopeptide repeat (PPR) proteins, which increased in expression up to 3-fold by 1 h following nutrient addition. PPR proteins are nuclear encoded proteins involved in chloroplast and mitochondria RNA processing. Correspondingly, other functions enriched in response to both nutrients were photosystem and ribosomal genes. Conclusions Microarray analysis provided transcriptomic evidence for N- but not P-limitation in K. brevis. Transcriptomic responses to the addition of either N or P suggest a concerted program leading to the reactivation of chloroplast functions. Even the earliest responding PPR protein transcripts possess a 5' SL sequence that suggests post-transcriptional control. Given the current state of knowledge of dinoflagellate gene regulation, it is currently unclear how these rapid changes in such transcript levels are achieved.