Recent CO2 levels promote increased production of the toxin parthenin in an invasive Parthenium hysterophorus biotype.

Recent carbon dioxide (CO2) concentrations promoted higher parthenin concentrations in an invasive Parthenium hysterophorus biotype. Mean concentrations of parthenin, an allelopathic and defensive sesquiterpene lactone, were 49% higher at recent (~400 ppm) than at mid-twentieth-century (~300 ppm) CO2 concentrations, but did not vary in a non-invasive biotype, suggesting that recent increases in atmospheric CO2 may have already altered the chemistry of this destructive weed, potentially contributing to its invasive success.

Ischemic Colitis Caused by Intra-Aortic Balloon Pump Counterpulsation.

Intra-aortic balloon pump counterpulsation (IABP) has been shown to prolong life in critically ill cardiac patients. However, complications including distal emboli, balloon rupture, bleeding, limb loss, and bowel ischemia continue to be associated with them. We present a case of a 56-year-old male who suffered bowel ischemia as a result of a malpositioned IABP. While the benefit of such devices in critically ill patients is not disputed, patients as well as clinicians should be aware of the potential side effects and patients undergoing IABP placement should be monitored for complications.

Editor's choice--Angulation of the C-arm during complex endovascular aortic procedures increases radiation exposure to the head.

OBJECTIVES/BACKGROUND: The increased complexity of endovascular aortic repair necessitates longer procedural time and higher radiation exposure to the operator, particularly to exposed body parts. The aims were to measure directly exposure to radiation of the bodies and heads of the operating team during endovascular repair of thoracoabdominal aortic aneurysms (TAAA), and to identify factors that may increase exposure. METHODS: This was a single-centre prospective study. Between October 2013 and July 2014, consecutive elective branched and fenestrated TAAA repairs performed in a hybrid operating room were studied. Electronic dosimeters were used to measure directly radiation exposure to the primary (PO) and assistant (AO) operator in three different areas (under-lead, over-lead, and head). Fluoroscopy and digital subtraction angiography (DSA) acquisition times, C-arm angulation, and PO/AO height were recorded. RESULTS: Seventeen cases were analysed (Crawford II-IV), with a median operating time of 280 minutes (interquartile range 200-330 minutes). Median age was 76 years (range 71-81 years); median body mass index was 28 kg/m(2) (25-32 kg/m(2)). Stent-grafts incorporated branches only, fenestrations only, or a mixture of branches and fenestrations. A total of 21 branches and 38 fenestrations were cannulated and stented. Head dose was significantly higher in the PO compared with the AO (median 54 µSv [range 24-130 µSv] vs. 15 µSv [range 7-43 µSv], respectively; p = .022), as was over-lead body dose (median 80 µSv [range 37-163 µSv] vs. 32 µSv [range 6-48 µSv], respectively; p = .003). Corresponding under-lead doses were similar between operators (median 4 µSv [range 1-17 µSv] vs. 1 µSv [range 1-3 µSv], respectively; p = .222). Primary operator height, DSA acquisition time in left anterior oblique (LAO) position, and degrees of LAO angulation were independent predictors of PO head dose (p < .05). CONCLUSIONS: The head is an unprotected area receiving a significant radiation dose during complex endovascular aortic repair. The deleterious effects of exposure to this area are not fully understood. Vascular interventionalists should be cognisant of head exposure increasing with C-arm angulation, and limit this manoeuvre.

Angiogenic cell therapy for critical limb ischemia: an update on concepts and trials.

Therapeutic neovascularization is a novel approach used to salvage critically ischemic limbs that are not amenable to conventional treatments. Initial efforts were based on single injections of angiogenic factors but there is now a realization that delivering angiogenic cells is more likely to achieve effective revascularization. Clinical studies to date have mostly used mixtures of mononuclear cells harvested from the bone marrow or peripheral blood. The modest results achieved with these cells, only a proportion of which are angiogenic, has stimulated a search for more potent cell types. Preclinical studies have identified several candidates, including adipose derived, embryonic and induced pluripotent stem cells. This review provides an update on the current status of angiogenic cell therapy for the ischemic limb and outlines efforts aimed at enhancing the clinical efficacy of treatments.

Peri-articular diseases of the hip: emerging frontiers in arthroscopic and endoscopic treatments.

The precise diagnosis of both intra and extra-capsular disease of the hip is now possible because of commonly available advanced diagnostic imaging techniques. An increasing number of reports in the orthopedic literature describe new endoscopic and arthroscopic techniques to address peri-articular pathology of the hip. The purpose of this paper is to review current techniques in the management of extra-articular hip conditions.

DNA quantification of exfoliated colonocytes as a novel screening tool for colorectal cancer.

AIMS: Colorectal cancer (CRC) sheds viable cells in the mucocelluar layer overlaying the colonic mucosa which travels distally alongside the faecal stream. These cells can be retrieved from the surface of the rectal mucosa. DNA quantification of these cells may be a marker of CRC, assessment of which was aim of this study. METHODS: A prospective double-blinded study of 467 consecutive patients referred with symptoms suggestive of CRC. Cells were collected from the surface of the rectal mucosa and total DNA quantified. DNA scores were compared with outcome after subjects had completed bowel investigations. Analysis of receiver operating characteristic (ROC) curves was performed to determine the optimum cut-off point for a positive result. RESULTS: 107 of the 467 patients were excluded due to; excessive faecal contamination of samples (n = 84); declined investigations (n = 17); inappropriate referral (n = 5); unfit (n = 1). 263 patients had lower GI endoscopy; 89 CT colonography and 8 barium enema. The diagnosis were; CRC (n = 23), inflammatory bowel disease (IBD) (n = 7), adenomatous polyps (AP) (n = 20) and no significant abnormality detected (n = 310). ROC analysis revealed that sensitivities at a specificity of 60% for detecting CRC were 91.3%; for CRC and IBD 86.7%; and for CRC, IBD and AP 72.0%. CONCLUSION: In symptomatic patients DNA quantification of cells retrieved from the surface of the rectal mucosa is sensitive for the detection of CRC. Although faecal contamination is a limitation of this technique, refinement and application of other molecular tests hold promise for a better non invasive method for the detection of CRC.

The utility of conditioning sequences in barostat protocols for the measurement of rectal compliance.

AIM: A barostat can be used to measure rectal sensitivity, compliance and elastance all of which are potentially important physiological parameters in the pathophysiology of faecal incontinence. Current practice recommends a conditioning distension sequence be performed prior to index distensions. We questioned the validity of this by comparing values for rectal compliance during sequential conditioning (CD) and index (ID) distensions in physiologically normal subjects. METHOD: Ten subjects (five men, mean age 55.2 years) with normal anal canal manometry, anorectal sensitivity and balloon distension thresholds were studied. After determining the minimum distension pressure, subjects underwent sequential isobaric distensions: CD 4 mmHg distensions every 45 s and ID 4 mmHg every 2 min, both to a maximum of 24 mmHg or patient tolerance. Compliance values from both sequences were calculated by measuring the maximum slope of pressure-volume curves. A paired t-test was performed to compare any differences between sequences. RESULTS: Mean rectal compliance were 11.4 ml/mmHg (SD 5.8 ml/mmHg) and 10.9 ml/mmHg (SD 5.7 ml/mmHg) in the CD and ID, respectively, with no statistical difference noted between distensions (P = 0.78). CONCLUSION: Rectal compliance can be measured with a single distension protocol without the need for an initial conditioning distension. Conditioning the rectum adds additional complexity to barostat protocols and is not necessary.

The influence of process and patient factors on the recall of consent information in mentally competent patients undergoing surgery for neck of femur fractures.

INTRODUCTION: Informed consent is an ethical and legal prerequisite for major surgical procedures. Recent literature has identified 'poor consent' as a major cause of litigation in trauma cases. We aimed to investigate the patient and process factors that influence consent information recall in mentally competent patients (abbreviated mental test score [AMTS] ≥6) presenting with neck of femur (NOF) fractures. METHODS: A prospective study was conducted at a tertiary unit. Fifty NOF patients (cases) and fifty total hip replacement (THR) patients (controls) were assessed for process factors (adequacy and validity of consent) as well as patient factors (comprehension and retention) using consent forms and structured interview proformas. RESULTS: The two groups were matched for ASA (American Society of Anesthesiologists) grade and AMTS. The consent forms were adequate in both groups but scored poorly for validity in the NOF group. Only 26% of NOF patients remembered correctly what surgery they had while only 48% recalled the risks and benefits of the procedure. These results were significantly poorer than in THR patients (p = 0.0001). CONCLUSIONS: This study confirms that NOF patients are poor at remembering the information conveyed to them at the time of consent when compared with THR patients despite being intellectually and physiologically matched. We suggest using preprinted consent forms (process factors), information sheets and visual aids (patient factors) to improve retention and recall.

Arthroscopy of the hip in patients following joint replacement.

Arthroscopy of the native hip is an established diagnostic and therapeutic procedure. Its application in the symptomatic replaced hip is still being explored. We describe the use of arthroscopy of the hip in 24 symptomatic patients following total hip replacement, resurfacing arthroplasty of the hip and partial resurfacing (study group), and compared it with arthroscopy of the native hip in 24 patients (control group). A diagnosis was made or confirmed at arthroscopy in 23 of the study group and a therapeutic arthroscopic intervention resulted in relief of symptoms in ten of these. In a further seven patients it led to revision hip replacement. In contrast, arthroscopy in the control group was diagnostic in all 24 patients and the resulting arthroscopic therapeutic intervention provided symptomatic relief in 21. The mean operative time in the study group (59.7 minutes (35 to 93)) was less than in the control group (71 minutes (40 to 100), p = 0.04) but the arthroscopic approach was more difficult in the arthroplasty group. We suggest that arthroscopy has a role in the management of patients with a symptomatic arthroplasty when other investigations have failed to provide a diagnosis.

Biomechanical comparison of interfragmentary compression in transverse fractures of the olecranon.

Compression and absolute stability are important in the management of intra-articular fractures. We compared tension band wiring with plate fixation for the treatment of fractures of the olecranon by measuring compression within the fracture. Identical transverse fractures were created in models of the ulna. Tension band wires were applied to ten fractures and ten were fixed with Acumed plates. Compression was measured using a Tekscan force transducer within the fracture gap. Dynamic testing was carried out by reproducing cyclical contraction of the triceps of 20 N and of the brachialis of 10 N. Both methods were tested on each sample. Paired t-tests compared overall compression and compression at the articular side of the fracture. The mean compression for plating was 819 N (sd 602, 95% confidence interval (CI)) and for tension band wiring was 77 N (sd 19, 95% CI) (p = 0.039). The mean compression on the articular side of the fracture for plating was 343 N (sd 276, 95% CI) and for tension band wiring was 1 N (sd 2, 95% CI) (p = 0.038). During simulated movements, the mean compression was reduced in both groups, with tension band wiring at -14 N (sd 7) and for plating -173 N (sd 32). No increase in compression on the articular side was detected in the tension band wiring group. Pre-contoured plates provide significantly greater compression than tension bands in the treatment of transverse fractures of the olecranon, both over the whole fracture and specifically at the articular side of the fracture. In tension band wiring the overall compression was reduced and articular compression remained negligible during simulated contraction of the triceps, challenging the tension band principle.

Effect of rectal distension on voluntary external anal sphincter function in healthy subjects.

AIM: Quantification of the anorectal reflex function is critical for explaining the physiological control of continence. Reflex external anal sphincter activity increases with rectal distension in a dynamic response. We hypothesized that rectal distension would similarly augment voluntary external anal sphincter function, quantified by measuring the anal maximum squeeze pressure. METHOD: Fifty-seven subjects (32 men, 25 women; median age 62 years), with normal anal canal manometry and endoanal ultrasound results, underwent a rectal barostat study with simultaneous anal manometry. Stepwise isovolumetric 50-ml distensions (n=35) or isobaric 4-mmHg distensions (n=22) above the minimum distending pressure were performed (up to 200 ml or 16 mmHg respectively), whilst anal resting pressure and maximum squeeze pressure were recorded and compared with the baseline pressure. RESULTS: The distension-induced squeeze increment was calculated as the maximum percentage increase in maximum squeeze pressure with progressive rectal distension. This was observed in 53 of the 57 subjects as a mean ± standard deviation (range) increase of 32.8 ± 24.1 (-5.5 to 97.7)%. The mean ± standard deviation (range) distension-induced squeeze increment in male subjects was 36.1 ± 25.7 (-5.5 to 97.7)% and in female subjects was 28.1 ± 20.1 (-3.8 to 70.2)%. There was no significant difference between the sexes (P=0.194). CONCLUSION: Rectal distension augments external anal sphincter function, confirming the existence of a dynamic rectoanal response. This may represent a quantifiable and important part of the continence mechanism.

Advantage of a one-stop referral and management service for ruptured abdominal aortic aneurysms.

BACKGROUND: In 2005, 4003 deaths in England and Wales were attributed to ruptured abdominal aortic aneurysm (RAAA). This study examined the referral and management patterns of this condition within one English county. METHODS: West Sussex has a population of 811 000 and is served by five hospitals with two main vascular networks. Between January 2005 and December 2007, data for community and in-hospital RAAA interventions and deaths were obtained. Probability of intervention and outcome for each network were calculated. RESULTS: Of 341 RAAA, 228 (66.9 per cent) presented to hospital. The mean distance travelled to hospitals with a full on-site vascular service was 17.6 (95 per cent confidence interval 15.5 to 19.7) km (124 patients) compared with 11.0 (9.5 to 12.7) km (104 patients) to hospitals with a partial or no vascular service (P < 0.001). Patients managed by the network with a one-stop RAAA management policy had an odds ratio of 2.4 for undergoing surgery and 2.5 for surviving the operation (P = 0.001 and P = 0.017 respectively). CONCLUSION: Patients with RAAA should be offered a one-stop emergency vascular service even if this involves further travel. Such a strategy offers significantly higher chance of intervention and survival from ruptured AAA.

Glomus tumour following a total knee replacement: a case report.

Pain following total knee replacement (TKR) is a common problem and cause of poor satisfaction amongst patients. We report on a glomus tumour causing pain on the anterolateral aspect of the knee, 2 years after an otherwise successful total knee replacement for osteoarthritis. The tumour was treated by excision biopsy under general anaesthesia and the diagnosis confirmed by histopathological examination. The removal of the tumour relieved the pain and the patient regained good function. We conclude that a thorough clinical assessment of a patient with a painful knee following TKR is essential to detect and treat coincidental painful pathology.

Primary tumour resection and survival in the palliative management of metastatic colorectal cancer.

AIM: To examine whether surgical resection of the primary tumour confers a survival benefit and to identify the predictive factors of outcome in patients presenting with asymptomatic metastatic colorectal cancer (CRC). MATERIALS AND METHODS: A review of a hospital database in a tertiary institution over a 6-year period (1999-2005) revealed 70 patients with asymptomatic primary CRC and unresectable liver metastases treated initially by systemic chemotherapy. A multivariate regression analysis model was used to determine the relative influence of multiple tumours, single/multiple liver metastases, tumour site, differentiation, response of liver and primary tumour to chemotherapy, biochemical response to chemotherapy, age at presentation, performance status and surgical intervention for the CRC primary. RESULTS: In 67 cases (3 lost to follow-up), 63 had multiple and 4 single surgically irresectable liver metastases. A total of 41 deaths were recorded. All patients received systemic chemotherapy and surgery was performed for bowel obstruction, bleeding or stable disease (n=32). Surgery (OR 0.26; p=0.00013) and clinical response of the primary tumour (OR 0.53; p=0.012) were independently associated with prolonged survival. Proximal tumours (OR 2.61; p=0.0075) and multiple primaries (OR 3.37; p=0.02) were associated with poor outcome. CONCLUSIONS: Surgical resection and response of the primary tumour to chemotherapy may be associated with improved survival, but proximal or multiple cancers predict poor outcome in patients with asymptomatic CRC and unresectable metastatic disease.

Morphine, opioids, and the feline pulmonary vascular bed.

BACKGROUND: Opioid-induced vasodepressor responses have been reported in a variety of species and laboratory models. The aim of this study was to ascertain the relative potencies of different clinically relevant opioids compared with traditional vasodepressor agents in the feline pulmonary vascular bed. A second aim was to study the effects of morphine and to identify the receptors involved in the mediation or the modulation of these effects. METHODS: This was a prospective vehicle-controlled study involving an intact chest preparation of adult mongrel cats. The effects of various opioids, morphine, fentanyl, remifentanil, sufentanil, and meperidine were compared with other vasodepressor agents. Additionally, the effects of L-N(5)-(1-iminoethyl) ornithine hydrochloride (L-NIO) (nitric oxide synthase inhibitor), nimesulide [selective cyclooxygenase (COX)-2 inhibitor], glibenclamide (ATP-sensitive K+ channel blocker), naloxone (non-selective opioid receptor antagonist), and diphenhydramine (histamine H(1)-receptor antagonist) were investigated on pulmonary arterial responses to morphine and other selected agonists in the feline pulmonary vascular bed. The systemic pressure and lobar arterial perfusion pressure were continuously monitored, electronically averaged, and recorded. RESULTS: In the cat pulmonary vascular bed of the isolated left lower lobe, morphine, remifentanil, fentanyl, sufentanil, and meperidine induced a dose-dependent moderate vasodepressor response and it appeared that sufentanil was the most potent on a nanomolar basis. The effects of morphine were not significantly altered after administration of L-NIO, nimesulide, and glibenclamide. However, the vascular responses to morphine were significantly attenuated following administration of naloxone and diphenhydramine. CONCLUSION: The results of the present study suggest that sufentanil appears to have slightly more potency and morphine the least of the five opioid agonists studied on a nanomolar basis. Morphine-induced vasodilatory responses appeared to be mediated or modulated by both opioid receptor and histamine-receptor-sensitive pathways.

Sphingosine-1-phosphate receptors: biology and therapeutic potential in kidney disease.

The major sphingolipid metabolite, sphingosine-1-phosphate (S1P), has important biological functions. S1P is the ligand for a family of five G-protein-coupled receptors with distinct signaling pathways that regulate angiogenesis, vascular maturation, immunity, chemotaxis, and other important biological pathways. Recently, clinical trials have targeted S1P receptors (S1PRs) for autoimmune diseases and transplantation and have generated considerable interest in developing additional, more selective compounds. This review summarizes current knowledge on the biology of S1P and S1PRs that forms the basis for future drug development and the treatment of kidney disease.

Paraplegia following elective endovascular repair of abdominal aortic aneurysm: reversal with cerebrospinal fluid drainage.

Paraplegia secondary to spinal cord ischaemia is a rare but devastating complication of abdominal aortic aneurysm repair. We report a case of paraplegia following elective endovascular repair of an infrarenal aortic aneurysm. A cerebrospinal fluid (CSF) drain was immediately inserted and resulted in full neurological recovery. This case highlights the fact that endovascular techniques are prone to similar complications as open surgery, and the importance of prompt cerebrospinal fluid drainage in cases of spinal cord ischaemia.

Reduction in varicose vein services: impact on operative training.

INTRODUCTION: This study examines the impact of rationing varicose vein operations on operative training on a general surgical unit with a vascular interest. PATIENTS AND METHODS: Log-books of middle-grade surgeons were analysed for 3-month periods before and after a decision by the local Primary Care Trust to ration varicose vein referrals. Number, intermediate equivalents and type of operations were recorded, whether they were general or vascular cases and whether the trainee had carried out or assisted with the operation. RESULTS: There was a slight fall in the total number of operations in which the middle-grade surgeons were involved (208 to 186). There was a significant increase in general surgical cases with the fall in number of varicose vein operations (P < 0.0001). The fall in case-load and work-load operative training in vascular surgery was compensated by an increase in general surgical cases (P = 0.0003). This was largely due to increased number of hernia repairs (P = 0.0035). CONCLUSIONS: From the point of operative training, a vascular unit in a district general hospital would not be sustainable following withdrawal of varicose vein services. However, this can be off-set by increasing general surgical case-load to fill the gap created.

Vascular surgery within general surgery: an analysis of workload 1989-2005.

INTRODUCTION: There is considerable debate as to whether vascular surgery should be a subspecialty separate from general surgery. This study examines the changing relationship between general and vascular surgery in a district general surgical unit over 16 years. PATIENTS AND METHODS: A detailed survey of referrals, admissions and operations to one unit was carried out over 3 months in 2003. This was compared with similar surveys in 1989, 1990 and 1995. In addition a 3-month audit of operations performed was carried out in 2005 following a decision by the Primary Care Trust (PCT) to reduce varicose vein referrals. RESULTS: There was a significant increase in the number of varicose vein and arterial referrals 1989-2003 (P = 0.0001 and P < 0.0001, respectively). This was reflected in increased number of vascular admissions (P < 0.0001). In 1989, 14% of the arterial cases were admitted as emergencies. This figure rose to 52% in 2003 (P < 0.0001). There was a significant increase in the number of arterial operations performed between 1989 and 1995; however, from 1995 to 2003 this number fell P < 0.0001). The number of varicose vein procedures increased significantly 1989-2003 (P < 0.0001), with a significant fall after the PCT decision (P < 0.0001). However, the number of operations carried out in 2005 increased slightly with the proportion of general surgical cases, mostly hernia repairs and laparoscopic cholecystectomies, increasing. CONCLUSIONS: With increasing specialisation comes the risk that reduction in any aspect of a particular specialty may result in that unit becoming unsustainable. In vascular surgery this will inevitably lead to centralisation of services. In a large district general hospital having two general surgeons with a vascular interest, the general surgical component has maintained the workload of the unit following reduction in varicose vein referrals.

Intra-abdominal and gastrointestinal tuberculosis.

OBJECTIVE: Reports suggest that the rates of tuberculosis (TB) continue to rise in the UK and throughout the world. The spread of the disease is aided by poverty, overcrowding, co-infection with human immunodeficiency virus and drug resistance. Consistent with the overall trend, intra-abdominal and gastrointestinal (GI) TB rates are rising. Tuberculosis is a treatable disease, whether occurring in the lungs or at extra-pulmonary sites but the nonspecific features of the disease result in difficulty in establishing a diagnosis. In this report, we have concentrated on the benefits and potential pitfalls of diagnostic methods. METHOD: A literature review was performed using the National Library of Medicine's Pubmed Database using the keywords diagnosis, management, abdominal and GI TB. RESULTS: Abdominal TB presents a particular challenge, as the diverse features of the disease do not readily suggest a particular diagnosis and diagnostic delays lead to significant morbidity and mortality. A number of investigative methods have been used to aid in the diagnosis of abdominal and GI TB. CONCLUSION: The nonspecific presentation of abdominal and GI TB present challenges in the diagnosis of this increasingly common disease. A high index of suspicion is an important factor in early diagnosis. After a diagnosis has been established, prompt initiation of treatment helps prevent morbidity and mortality.