Environmental drivers of increased ecosystem respiration in a warming tundra

Arctic and alpine tundra ecosystems are large reservoirs of organic carbon1,2. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere3,4. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain5-7. This hampers the accuracy of global land carbon-climate feedback projections7,8. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1 year up to 25 years. We show that a mean rise of 1.4 °C [confidence interval (CI) 0.9-2.0 °C] in air and 0.4 °C [CI 0.2-0.7 °C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22-38%] (n = 136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n = 9) and continued for at least 25 years (n = 136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.

Location of Retroperitoneal Lymph Node Metastases in Upper Tract Urothelial Carcinoma: Results from a Prospective Lymph Node Mapping Study

Background

There is limited information on the distribution of retroperitoneal lymph node metastases (LNMs) in upper tract urothelial carcinoma (UTUC).

Objective

To investigate the location of LNMs in UTUC of the renal pelvis or proximal ureter and short-term complications after radical nephroureterectomy (RNU) with lymph node dissection (LND).

Design setting and participants

This was a prospective Nordic multicenter study (four university hospitals, two county hospitals). Patients with clinically suspected locally advanced UTUC (stage >T1) and/or clinical lymph node-positive (cN+) disease were invited to participate. Participants underwent RNU and fractionated retroperitoneal LND using predefined side-specific templates.

Outcome measurements and statistical analysis

The location of LNMs in the LND specimen and retroperitoneal lymph node recurrences during follow-up was recorded. Postoperative complications within 90 d of surgery were ascertained from patient charts. Descriptive statistics were used.

Results and limitations

LNMs were present in the LND specimen in 23/100 patients, and nine of 100 patients experienced a retroperitoneal recurrence. Distribution per side revealed LNMs in the LND specimen in 11/38 (29%) patients with right-sided tumors, for whom the anatomically larger, right-sided template was used, in comparison to 12/62 (19%) patients with left-sided tumors, for whom a more limited template was used. High-grade complications (Clavien grade ≥3) within 90 d of surgery were registered for 13/100 patients. The study is limited in size and not powered to assess survival estimates.

Conclusions

The suggested templates that we prospectively applied for right-sided and left-sided LND in patients with advanced UTUC included the majority of LNMs. High-grade complications directly related to the LND part of the surgery were limited.

Patient summary

This study describes the location of lymph node metastases in patients with cancer in the upper urinary tract who underwent surgery to remove the affected kidney and ureter. The results show that most metastases occur within the template maps for lymph node surgery that we investigated, and that this surgery can be performed with few severe complications.

Urosymphyseal fistula after pelvic radiotherapy in a tertial referral centre - a rare entity with significant comorbidity requiring multidisciplinary management

OBJECTIVE

To report population-based clinical presentation and outcomes in patients with urosymphyseal fistula (USF) after pelvic radiotherapy (RT).

PATIENTS AND METHODS

A retrospective chart review was performed in 33 consecutive patients diagnosed with suspicion of USF in a tertial referral center from 2014-2022 to ascertain information about diagnostic delay, clinical presentation, precipitating causes, treatments received and outcomes during the median 22 months follow-up. Out of 33 consecutive patients with suspicion of USF, one female with vesicovaginal fistula, one patient developing RT-associated bladder angiosarcoma, four patients with short follow-up (<3 months), and three patients that during chart review not were considered to have a USF were excluded.

RESULTS

In all, 24 males with a median age of 77 years were diagnosed with USF. Local pain was the predominating symptom in 17/24 (71%) patients. Endourologic manipulations preceded the diagnosis of USF in 16 patients. Five patients had a diagnostic delay of more than 3 months. At diagnosis, 20/24 patients had radiological signs of osteomyelitis, and five had a concomitant rectourethral fistula. Due to comorbidity, five patients were not amenable to any other interventions than urinary catheter or suprapubic tube in conjunction with long-term antibiotics, of which three died from infections related to the USF. Out of the remaining 19 patients receiving some form of urinary diversion, five had recurrent osteomyelitis, of which four did not undergo cystectomy in conjunction with surgery for the USF.

CONCLUSIONS

Urethral endourologic interventions in patients previously subjected to pelvic RT should be performed cautiously.

Robot-assisted nephroureterectomy for upper tract urothelial carcinoma-feasibility and complications: a single center experience

BACKGROUND

Robot-assisted nephroureterectomy (RANU) is the primary treatment for upper tract urothelial carcinoma (UTUC) at our hospital for patients with clinical stage less than T2, and for patients with invasive tumours, but unfit for major surgery.

OBJECTIVE

To assess peri-operative conditions and outcomes of RANU at our unit, and to evaluate the safety of the procedure.

METHODS

The medical records of all 166 patients undergoing RANU for suspected UTUC and followed for more than three months in a large university hospital in Sweden were reviewed retrospectively. After the exclusion of twenty patients because of previous cystectomy, simultaneous surgical procedure, or other tumour types than UTUC in the pathological report, 146 patients remained for the analyses. The primary endpoint was complication rate according to Clavien-Dindo at 90 days. Secondary endpoints were perioperative bleeding, violation of oncological surgical principles, hospital stay, and re-admission within 90 days.

RESULTS

The median age was 75 [(Inter Quartile Range) IQR 70-80] years and 57% of the patients had an ASA score above 2. According to Clavien-Dindo, one patient had a grade 3 complication, and no patient had a grade 4-5 complication. The median blood loss was 50 (IQR 20-100) ml and the median hospital stay was 6 (IQR 5-7) days. Twelve patients were re-admitted to the hospital within 90 days (eight with urinary tract infection/haematuria, one with hematoma, and three with other diseases).

CONCLUSION

Robot-assisted nephroureterectomy is a safe procedure for patients with upper tract urothelial carcinoma, with a low risk of major surgical complications.

Learning curve for robot-assisted laparoscopic radical prostatectomy in a large prospective multicentre study

OBJECTIVE

Differences in outcome after radical prostatectomy for prostate cancer can partly be explained by intersurgeon differences, where degree of experience is one important aspect. This study aims to define the learning curve of robot-assisted laparoscopic prostatectomy (RALP) regarding oncological and functional outcomes.

MATERIALS AND METHODS

Out of 4003 enrolled patients in the LAPPRO trial, 3583 met the inclusion criteria, of whom 885 were operated on by an open technique. In total, 2672 patients with clinically localized prostate cancer from seven Swedish centres were operated on by RALP and followed for 8 years (LAPPRO trial). Oncological outcomes were pathology-reported surgical margins and biochemical recurrence at 8 years. Functional outcomes included patient-reported urinary incontinence and erectile dysfunction at 3, 12 and 24 months. Experience was surgeon-reported experience before and during the study. The relationship between surgeon experience and functional outcomes and surgical margin status was analysed by mixed-effects logistic regression. Biochemical recurrence was analysed by Cox regression, with robust standard errors.

RESULTS

The learning curve for positive surgical margins was relatively flat, with rates of 21% for surgeons who had performed 0-74 cases and 24% for surgeons with > 300 cases. Biochemical recurrence at 4 years was 11% (0-74 cases) and 13% (> 300 cases). Incontinence was stable over the learning curve, but erectile function improved at 2 years, from 38% (0-74 cases) to 53% (> 300 cases).

CONCLUSIONS

Analysis of the learning curve for surgeons performing RALP showed that erectile function improved with increasing number of procedures, which was not the case for oncological outcomes.

Functional and Oncological Outcomes After Open Versus Robot-assisted Laparoscopic Radical Prostatectomy for Localised Prostate Cancer: 8-Year Follow-up

BACKGROUND

Radical prostatectomy reduces mortality among patients with localised prostate cancer. Evidence on whether different surgical techniques can affect mortality rates is lacking.

OBJECTIVE

To evaluate functional and oncological outcomes 8 yr after robot-assisted laparoscopic prostatectomy (RALP) and open retropubic radical prostatectomy (RRP).

DESIGN, SETTING, AND PARTICIPANTS

We enrolled 4003 patients in a prospective, controlled, nonrandomised trial comparing RALP and RRP in 14 Swedish centres between 2008 and 2011. Data for functional outcomes were assessed via validated patient questionnaires administered preoperatively and at 12 and 24 mo and 8 yr after surgery.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was urinary incontinence. Functional outcomes at 8 yr were analysed using the modified Poisson regression approach.

RESULTS AND LIMITATIONS

Urinary incontinence was not significantly different at 8 yr after surgery between RALP and RRP (27% vs 29%; adjusted risk ratio [aRR] 1.05, 95% confidence interval [CI] 0.90-1.23). Erectile dysfunction was significantly lower in the RALP group (66% vs 70%; aRR 0.93, 95% CI 0.87-0.99). Prostate cancer-specific mortality (PCSM) was significantly lower in the RALP group at 8 yr after surgery (40/2699 vs 25/885; aRR 0.56, 95% CI 0.34-0.93). Differences in oncological outcomes were mainly seen in the group with high D'Amico risk, with a lower risk of positive surgical margins (21% vs 34%), biochemical recurrence (51% vs 69%), and PCSM (14/220 vs 11/77) for RALP versus RRP. The main limitation is the nonrandomised design.

CONCLUSIONS

In this prospective multicentre controlled trial, PCSM at 8 yr after surgery was lower for RALP in comparison to RRP. A causal relationship between surgical technique and mortality cannot be inferred, but the result confirms that RALP is oncologically safe. Taken together with better short-term results reported elsewhere, our findings confirm that implementation of RALP may continue.

PATIENT SUMMARY

Our study comparing two surgical techniques for removal of the prostate for localised prostate cancer shows that a robot-assisted minimally invasive technique is safe in the long term. Together with previous results showing some better short-term effects with this approach, our findings support continued use of robot-assisted surgery.

Surgeon heterogeneity significantly affects functional and oncological outcomes after radical prostatectomy in the Swedish LAPPRO trial

Objectives

To evaluate how surgeon heterogeneity – the variation in outcomes between individual surgeons – influences functional and oncological outcomes after robot‐assisted laparoscopic prostatectomy (RALP) and retropubic radical prostatectomy (RRP), and to assess whether surgeon heterogeneity affects the comparison between RALP and RRP.

Patients and Methods

Laparoscopic Prostatectomy Robot Open (LAPPRO) is a prospective, controlled, non‐randomized trial performed at 14 Swedish centres with 68 operating surgeons. A total of 4003 men with localized prostate cancer were enrolled between 2008 and 2011. The endpoints were urinary incontinence, erectile dysfunction (ED) and recurrence at 24 months after surgery. Logistic regression models were built to evaluate surgeon heterogeneity and, secondarily, surgeon‐specific factors were added to the models to investigate their influence on heterogeneity and the comparison between RALP and RRP.

Results

Among surgeons who performed at least 20 surgeries during the study period (n=25), we observed statistically significant heterogeneity for incontinence (P = 0.001), ED (P < 0.001) and rate of recurrent disease (P < 0.001). The significant heterogeneity remained when analysing only experienced surgeons with a stated experience of at least 250 radical prostatectomies (n=12). Among all participating surgeons (n=68), differences in surgeon volume explained 42% of the observed heterogeneity for incontinence (P = 0.003), 11% for ED (P = 0.03) and 19% for recurrence (P = 0.01). Taking surgeon volume into account when comparing RALP and RRP had a significant impact on the results. The effect was greatest for functional outcomes, and the additional adjustments for the surgeons' previous experience changed whether the difference between techniques was statistically significant or not. The surgeons’ annual volume had the greatest effect on the recurrence rate.

Conclusions

There was a large degree of heterogeneity among surgeons regarding both functional and oncological outcomes and this had a significant impact on the results when comparing RALP and RRP. Some of the observed heterogeneity was explained by differences in surgeon volume. Efforts to decrease heterogeneity are warranted and variation among surgeons must be accounted for when conducting comparative analyses between surgical techniques.

Risk of Recurrent Disease 6 Years After Open or Robotic-assisted Radical Prostatectomy in the Prospective Controlled Trial LAPPRO

Background

Conclusive evidence of superiority in oncological outcome for robot-assisted laparoscopic prostatectomy (RALP) over retropubic radical prostatectomy (RRP) is lacking.

Objective

To compare RALP and RRP regarding recurrent disease and to report the mortality rate 6 yr after surgery.

Design, setting, and participants

A total of 4003 men with localized prostate cancer were enrolled between 2008 and 2011 in Laparoscopic Prostatectomy Robot Open (LAPPRO)— a prospective, controlled, nonrandomized trial performed at 14 Swedish centers.

Outcome measurements and statistical analysis

Data were collected at visits and by patient questionnaires at 3, 12, and 24 mo, and through a structured telephone interview at 6 yr. Cause of death was retrieved from the National Cause of Death Register in Sweden. The modified Poisson regression approach was used for analyses.

Results and limitations

After adjustment for patient-, tumor-, and surgeon-related confounders, no statistically significant difference was observed between RALP and RRP in biochemical recurrence rate (14 vs 16%, relative risk [RR] 0.77, 95% confidence interval [CI] 0.56–1.06) or in not cured endpoint (22% vs 23%, RR 0.82, 95% CI 0.6–1.11). Stratified by D’Amico risk group, a significant benefit for RALP existed for recurrent disease in high-risk patients (RR 0.47, 95% CI 0.26–0.86, p = 0.02). All-cause mortality was 3% (n = 96). Prostate cancer–specific mortality was 0.6% (n = 21) overall, 0.3% (n = 8) after RALP, and 1.5% (n = 13) after RRP. The nonrandomized design is a limitation.

Conclusions

No significant difference was observed for cancer recurrence rate between RALP and RRP 6 yr after surgery. However, in a subgroup analysis, we found a significant benefit for RALP regarding recurrence rate in the high-risk group. Larger studies with longer follow-up are needed to make a firm conclusion and to evaluate a possible survival benefit.

Patient summary

In general, the oncological outcome is comparable between robotic and open radical prostatectomy 6 yr after surgery. For high-risk patients, our findings indicate that there is an advantage for robotics, but further studies with longer follow-up time is needed to make a firm conclusion.

Determination of Ochratoxin A in Currants, Raisins, Sultanas, Mixed Dried Fruit, and Dried Figs by Immunoaffinity Column Cleanup with Liquid Chromatography: Interlaboratory Study

An interlaboratory study was performed on behalf of the Food Standards Agency to evaluate the effectiveness of an affinity column cleanup liquid chromatographic (LC) method for the determination of ochratoxin A in a variety of dried fruit at European regulatory limits. To ensure homogeneity before analysis, laboratory samples are normally slurried with water in the ratio of 5 parts fruit to 4 parts water, and test materials in this form were used in the study. The test portion was extracted with acidified methanol. The extract was filtered, diluted with phosphate-buffered saline, and applied to an affinity column. The column was washed and ochratoxin A was eluted with methanol. Ochratoxin A was quantified by reversed-phase LC. The use of post-column pH shift to enhance the fluorescence of ochratoxin A by the addition of 1.1M ammonia solution to the column eluant is optional. Determination was by fluorescence. Currants, sultanas, raisins, figs, and mixed fruit (comprising dried pineapple, papaya, sultanas, prunes, dates, and banana chips), both naturally contaminated and blank (very low level), were sent to 24 collaborators in 7 European countries. Participants were asked to spike test portions of all test samples at a level equivalent to 5 ng/g ochra toxin A. Average recoveries ranged from 69 to 74%. Based on results for 5 naturally contaminated test samples (blind duplicates) the relative standard deviation for repeatability (RSDr) ranged from 4.9 to 8.7%, and the relative standard deviation for reproducibility (RSDR)rangedfrom14to28%. The method showed acceptable within-and be-tween-laboratory precision for all 5 matrixes, as evidenced by HORRAT values &lt;1.3.

Single institution followed by national implementation of systematic surgical quality control and feedback for radical prostatectomy: a 20-year journey

Purpose

The demand for objective and outcome-based facts about surgical results after radical prostatectomy (RP) is increasing. Systematic feedback is also essential for each surgeon to improve his/her performance.

Methods

RP outcome data (e.g., pT-stage and margin status) have been registered at Sahlgrenska University Hospital (SUH) since 1988 and patient-related outcome measures (PROM) have been registered since 2001. The National Prostate Cancer Registry (NPCR) has covered all Regions in Sweden since 1998 and includes PROM-data from 2008. Initially PROM was on-paper questionnaires but due since 2018 all PROMs are collected electronically. In 2014 an on-line “dashboard” panel was introduced, showing the results for ten quality-control variables in real-time. Since 2017 all RP data on hospital, regional, and national levels are publicly accessible on-line on “www.npcr.se/RATTEN”.

Results

The early PROM-data from SUH have been used for internal quality control. As national clinical and PROM-data from the NPCR have been made accessible on-line and in real-time we have incorporated this into our pre-existing protocol. Our data are now internally available as real-time NPCR reports on the individual surgeons’ results, as well as ePROM data. We can compare the results of each surgeon internally and to other departments’ aggregated data. The public can access data and compare hospital level data on “RATTEN”.

Conclusions

The process of quality control of RP locally at SUH, and nationally through the NPCR, has been long but fruitful. The online design, with direct real-time feedback to the institutions that report the data, is essential.

Functional and Oncologic Outcomes Between Open and Robotic Radical Prostatectomy at 24-month Follow-up in the Swedish LAPPRO Trial

BACKGROUND

The adoption of robot-assisted laparoscopic radical prostatectomy (RALP) has increased rapidly, despite lack of conclusive evidence of its superiority regarding long-term outcomes over open retropubic RP (RRP). In 2015, we reported on 12-mo follow-up from the LAPPRO trial showing a moderate advantage of RALP regarding erectile dysfunction. No significant differences were seen for urinary incontinence or surgical margin status.

OBJECTIVE

To present patient-reported functional outcomes and recurrent and residual disease at 24-mo follow-up from the prospective multicenter LAPPRO trial.

DESIGN, SETTING, AND PARTICIPANTS

A total of 4003 patients with clinically localized prostate cancer were recruited from 14 Swedish centers, seven performing RALP and seven RRP.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Data were only analyzed for patients operated on by surgeons with >100 prior RPs. Adjusted odds ratios (AORs) were calculated using logistic regression, with adjustment for differences in patient mix.

RESULTS AND LIMITATIONS

At 24 mo, there was a significant difference in erectile dysfunction in favor of RALP (68% vs 74%; AOR 0.72, 95% confidence interval [CI] 0.57-0.91; p=0.006). No significant difference was observed for incontinence (19% vs 16%; AOR 1.29, 95% CI 1.00-1.67; p=0.053) or recurrent or residual disease (13% vs 13%; AOR 0.79, 95% CI 0.59-1.07; p=0.13). We did not adjust for individual surgeon volume and experience, which is a potential limitation.

CONCLUSIONS

Extended follow-up corroborated our previous report at 12 mo of a persistent RALP benefit regarding potency.

PATIENT SUMMARY

LAPPRO is a Swedish trial comparing two different prostate cancer surgical techniques (robotic compared to open). At 24-mo follow-up after surgery there was a moderate advantage for the robotic technique regarding erectile dysfunction (potency), while there was a small but not significant difference in urinary leakage in favor of open surgery. We did not find any difference regarding cancer relapse.

Aerobic exercise training lowers platelet reactivity and improves platelet sensitivity to prostacyclin in pre- and postmenopausal women

Essentials It is unknown how regular exercise affects platelet function after menopause. We studied the effect of 3-months of high-intensity exercise in pre- and postmenopausal women. Platelet sensitivity to the inhibitory effect of arterially infused prostacyclin was increased. Reduced basal platelet reactivity was seen in the premenopausal women only.

SUMMARY

Background The risk of atherothrombotic events increases after the menopause. Regular physical activity has been shown to reduce platelet reactivity in younger women, but it is unknown how regular exercise affects platelet function after the menopause. Objectives To examine the effects of regular aerobic exercise in late premenopausal and recent postmenopausal women by testing basal platelet reactivity and platelet sensitivity to prostacyclin and nitric oxide. Methods Twenty-five sedentary, but healthy, late premenopausal and 24 matched recently postmenopausal women, mean (95% confidence interval) 49.1 (48.2-49.9) and 53.7 (52.5-55.0) years old, participated in an intervention study: 3-month high-intensity supervised aerobic spinning-cycle training (1 h, × 3/week). Basal platelet reactivity was analyzed in platelet-rich plasma from venous blood as agonist-induced % aggregation. In a subgroup of 13 premenopausal and 14 postmenopausal women, platelet reactivity was tested ex vivo after femoral arterial infusion of prostacyclin, acetylcholine, a cyclooxygenase inhibitor, and after acute one-leg knee extensor exercise. Results Basal platelet reactivity (%aggregation) to TRAP-6 (1 μm) was higher in the postmenopausal, 59% (50-68), than the premenopausal women, 45% (35-55). Exercise training reduced basal platelet reactivity to collagen (1 μg mL-1 ) in the premenopausal women only: from 63% (55-71%) to 51% (41-62%). After the training intervention, platelet aggregation was more inhibited by the arterial prostacyclin infusion and the acute exercise in both premenopausal and postmenopausal women. Conclusions These results highlight previously unknown cardioprotective aspects of regular aerobic exercise in premenopausal and postmenopausal women, improving their regulation of platelet reactivity through an increased platelet sensitivity to prostacyclin, which may counterbalance the increased atherothrombotic risk associated with the menopause.

Capillary growth, ultrastructure remodelling and exercise training in skeletal muscle of essential hypertensive patients

AIM

The aim was to elucidate whether essential hypertension is associated with altered capillary morphology and density and to what extent exercise training can normalize these parameters.

METHODS

To investigate angiogenesis and capillary morphology in essential hypertension, muscle biopsies were obtained from m. vastus lateralis in subjects with essential hypertension (n = 10) and normotensive controls (n = 11) before and after 8 weeks of aerobic exercise training. Morphometry was performed after transmission electron microscopy, and protein levels of several angioregulatory factors were determined.

RESULTS

At baseline, capillary density and capillary-to-fibre ratio were not different between the two groups. However, the hypertensive subjects had 9% lower capillary area (12.7 ± 0.4 vs. 13.9 ± 0.2 μm(2)) and tended to have thicker capillary basement membranes (399 ± 16 vs. 358 ± 13 nm; P = 0.094) than controls. Protein expression of vascular endothelial growth factor (VEGF), VEGF receptor-2 and thrombospondin-1 were similar in normotensive and hypertensive subjects, but tissue inhibitor of matrix metalloproteinase was 69% lower in the hypertensive group. After training, angiogenesis was evident by 15% increased capillary-to-fibre ratio in the hypertensive subjects only. Capillary area and capillary lumen area were increased by 7 and 15% in the hypertensive patients, whereas capillary basement membrane thickness was decreased by 17% (P < 0.05). VEGF expression after training was increased in both groups, whereas VEGF receptor-2 was decreased by 25% in the hypertensive patients(P < 0.05).

CONCLUSION

Essential hypertension is associated with decreased lumen area and a tendency for increased basement membrane thickening in capillaries of skeletal muscle. Exercise training may improve the diffusion conditions in essential hypertension by altering capillary structure and capillary number.

Dual-modality probe intended for prostate cancer detection combining Raman spectroscopy and tactile resonance technology--discrimination of normal human prostate tissues ex vivo

Prostate cancer is the most common cancer for men in the western world. For the first time, a dual-modality probe, combining Raman spectroscopy and tactile resonance technology, has been used for assessment of fresh human prostate tissue. The study investigates the potential of the dual-modality probe by testing its ability to differentiate prostate tissue types ex vivo. Measurements on four prostates show that the tactile resonance modality was able to discriminate soft epithelial tissue and stiff stroma (p < 0.05). The Raman spectra exhibited a strong fluorescent background at the current experimental settings. However, stroma could be discerned from epithelia by integrating the value of the spectral background. Combining both parameters by a stepwise analysis resulted in 100% sensitivity and 91% specificity. Although no cancer tissue was analysed, the results are promising for further development of the instrument and method for discriminating prostate tissues and cancer.

Nitric oxide and reactive oxygen species in limb vascular function: what is the effect of physical activity?

Nitric oxide (NO) is known to be one of the most important regulatory compounds within the cardiovascular system where it is central for functions such as regulation of blood pressure, blood flow, and vascular growth. The bioavailability of NO is determined by a balance between, on one hand, the extent of enzymatic and non-enzymatic formation of NO and on the other hand, removal of NO, which in part is dependent on the reaction of NO with reactive oxygen species (ROS). The presence of ROS is dependent on the extent of ROS formation via mitochondria and/or enzymes such as NAD(P)H oxidase (NOX) and xanthine oxidase (XO) and the degree of ROS removal through the antioxidant defense system or other reactions. The development of cardiovascular disease has been proposed to be closely related to a reduced bioavailability of NO in parallel with an increased presence of ROS. Excessive levels of ROS not only lower the bioavailability of NO but may also cause cellular damage in the cardiovascular system. Physical activity has been shown to greatly improve cardiovascular function, in part through improved bioavailability of NO, enhanced endogenous antioxidant defense and a lowering of the expression of ROS-forming enzymes. Regular physical activity is therefore likely to be a highly useful tool in the treatment of cardiovascular disease. Future studies should focus on which form of exercise may be most optimal for enhancing NO bioavailability and improving cardiovascular health.

Physical activity opposes the age-related increase in skeletal muscle and plasma endothelin-1 levels and normalizes plasma endothelin-1 levels in individuals with essential hypertension

AIMS

Endothelin-1 has potent constrictor and proliferative activity in vascular smooth muscle, and essential hypertension and aging are associated with increased endothelin-1-mediated vasoconstrictor tone. The aim of this study was to investigate the effect of physical activity, hypertension and age on endothelin-1 levels in plasma and skeletal muscle and endothelin receptors in skeletal muscle in human subjects.

METHODS

In study 1, normotensive (46 ± 1 years, n = 11) and hypertensive (47 ± 1 years, n = 10) subjects were studied before and after 8 weeks of aerobic exercise training. In study 2, young (23 ± 1 years, n = 8), older lifelong sedentary (66 ± 2 years, n = 8) and older lifelong endurance-trained (62 ± 2 years, n = 8) subjects were studied in a cross-sectional design.

RESULTS

Skeletal muscle and plasma endothelin-1 levels were increased with age and plasma endothelin-1 levels were higher in hypertensive than normotensive individuals. Eight weeks of exercise training normalized plasma endothelin-1 levels in the hypertensive subjects and increased the protein expression of the ET(A) receptor in skeletal muscle of normotensive subjects. Similarly, individuals that had performed lifelong physical activity had similar plasma and muscle endothelin-1 levels as the young controls and had higher ET(A) receptor levels.

CONCLUSION

Our findings suggest that aerobic exercise training opposes the age-related increase in skeletal muscle and plasma endothelin-1 levels and normalizes plasma endothelin-1 levels in individuals with essential hypertension. This effect may explain some of the beneficial effects of training on the cardiovascular system in older and hypertensive subjects.

Influence of nitrate supplementation on VO₂ kinetics and endurance of elite cyclists

The present study examined if an elevated nitrate intake would improve VO(2) kinetics, endurance, and repeated sprint capacity in elite endurance athletes. Ten highly trained cyclists (72 ± 4 mL O(2) /kg/min, mean ± standard deviation) underwent testing for VO(2) kinetics (3 × 6 min at 298 ± 28 W), endurance (120 min preload followed by a 400-kcal time trial), and repeated sprint capacity (6 × 20 s sprints, recovery 100 s) during two 6-day periods in randomized order with a daily ingestion of either 0.5 L beetroot (BR) juice to increase nitrate levels or a 0.5 L placebo (PLA) drink with blackcurrant juice. Plasma NOx (nitrate + nitrite) levels were higher (P < 0.01) in BR (147 ± 102 and 159 ± 103 μM after 4 and 6 days of beverage intake, respectively) compared with PLA (41 ± 10 and 40 ± 7 μM). VO(2) kinetics and exercise economy were the same in BR and PLA. Time-trial performance was similar with an average completion time of 18:20 and 18:37 min:s in BR and PLA, respectively, with average power outputs of 290 ± 43 W in BR and 285 ± 44 W in PLA. Peak and mean power during repeated sprinting were similar in BR and PLA. In contrast to observations in moderately trained subjects intake of BR juice had no effect on VO(2) kinetics and performance in elite cyclists.

Vasodilator interactions in skeletal muscle blood flow regulation

During exercise, oxygen delivery to skeletal muscle is elevated to meet the increased oxygen demand. The increase in blood flow to skeletal muscle is achieved by vasodilators formed locally in the muscle tissue, either on the intraluminal or on the extraluminal side of the blood vessels. A number of vasodilators have been shown to bring about this increase in blood flow and, importantly, interactions between these compounds seem to be essential for the precise regulation of blood flow. Two compounds stand out as central in these vasodilator interactions: nitric oxide (NO) and prostacyclin. These two vasodilators are both stimulated by several compounds, e.g. adenosine, ATP, acetylcholine and bradykinin, and are affected by mechanically induced signals, such as shear stress. NO and prostacyclin have also been shown to interact in a redundant manner where one system can take over when formation of the other is compromised. Although numerous studies have examined the role of single and multiple pharmacological inhibition of different vasodilator systems, and important vasodilators and interactions have been identified, a large part of the exercise hyperaemic response remains unexplained. It is plausible that this remaining hyperaemia may be explained by cAMP- and cGMP-independent smooth muscle relaxation, such as effects of endothelial derived hyperpolarization factors (EDHFs) or through metabolic modulation of sympathetic effects. The nature and role of EDHF as well as potential novel mechanisms in muscle blood flow regulation remain to be further explored to fully elucidate the regulation of exercise hyperaemia.

Lifelong physical activity preserves functional sympatholysis and purinergic signalling in the ageing human leg

Ageing is associated with an impaired ability to modulate sympathetic vasoconstrictor activity (functional sympatholysis) and a reduced exercise hyperaemia. The purpose of this study was to investigate whether a physically active lifestyle can offset the impaired functional sympatholysis and exercise hyperaemia in the leg and whether ATP signalling is altered by ageing and physical activity. Leg haemodynamics, interstitial [ATP] and P2Y(2) receptor content was determined in eight young (23 ± 1 years), eight lifelong sedentary elderly (66 ± 2 years) and eight lifelong active elderly (62 ± 2 years) men at rest and during one-legged knee extensions (12 W and 45% maximal workload (WL(max))) and arterial infusion of ACh and ATP with and without tyramine. The vasodilatory response to ACh was lowest in the sedentary elderly, higher in active elderly (P < 0.05) and highest in the young men (P < 0.05), whereas ATP-induced vasodilatation was lower in the sedentary elderly (P < 0.05). During exercise (12 W), leg blood flow, vascular conductance and VO2 was lower and leg lactate release higher in the sedentary elderly compared to the young (P < 0.05), whereas there was no difference between the active elderly and young. Interstitial [ATP] during exercise and P2Y(2) receptor content were higher in the active elderly compared to the sedentary elderly (P < 0.05). Tyramine infusion lowered resting vascular conductance in all groups, but only in the sedentary elderly during exercise (P < 0.05). Tyramine did not alter the vasodilator response to ATP infusion in any of the three groups. Plasma [noradrenaline] increased more during tyramine infusion in both elderly groups compared to young (P < 0.05). A lifelong physically active lifestyle can maintain an intact functional sympatholysis during exercise and vasodilator response to ATP despite a reduction in endothelial nitric oxide function. A physically active lifestyle increases interstitial ATP levels and skeletal muscle P2Y(2) receptor content.

Contribution of intravascular versus interstitial purines and nitric oxide in the regulation of exercise hyperaemia in humans

The regulation of blood flow to skeletal muscle involves a complex interaction between several locally formed vasodilators that are produced both in the skeletal muscle interstitium and intravascularly. The gas nitric oxide (NO) and the purines ATP and adenosine, are potent vasodilators that are formed by multiple cell types and released into the skeletal muscle interstitium and in plasma in response to muscle contraction. Cellular sources of ATP and NO in plasma are erythrocytes and endothelial cells, whereas interstitial sources are skeletal muscle cells and endothelial cells. Adenosine originates primarily from extracellular degradation of ATP. During exercise the concentrations of ATP and adenosine increase markedly in the interstitium with smaller increases occurring in plasma, and thus the interstitial concentration during exercise is severalfold higher than in plasma. The concentration of NO metabolites (NOx) in interstitium and plasma does not change during exercise and is similar in the two compartments. Adenosine and NO have been shown to contribute to exercise hyperaemia whereas the role of ATP remains unclear due to lack of specific purinergic receptor blockers. The relative role of intravascular versus interstitial vasodilators is not known but evidence suggests that both compartments are important. In cardiovascular disease, a reduced capacity to form adenosine in the muscle interstitium may be a contributing factor in increased peripheral vascular resistance.

Electronic structure of a vapor-deposited metal-free phthalocyanine thin film

The electronic structure of a vapor-sublimated thin film of metal-free phthalocyanine (H2Pc) is studied experimentally and theoretically. An atom-specific picture of the occupied and unoccupied electronic states is obtained using x-ray-absorption spectroscopy (XAS), core- and valence-level x-ray photoelectron spectroscopy (XPS), and density-functional theory (DFT) calculations. The DFT calculations allow for an identification of the contributions from individual nitrogen atoms to the experimental N1s XAS and valence XPS spectra. This comprehensive study of metal-free phthalocyanine is relevant for the application of such molecules in molecular electronics and provides a solid foundation for identifying modifications in the electronic structure induced by various substituent groups.

The hydrogen bond in ice probed by soft x-ray spectroscopy and density functional theory

We combine photoelectron and x-ray absorption spectroscopy with density functional theory to derive a molecular orbital picture of the hydrogen bond in ice. We find that the hydrogen bond involves donation and back-donation of charge between the oxygen lone pair and the O-H antibonding orbitals on neighboring molecules. Together with internal s-p rehybridization this minimizes the repulsive charge overlap of the connecting oxygen and hydrogen atoms, which is essential for a strong attractive electrostatic interaction. Our joint experimental and theoretical results demonstrate that an electrostatic model based on only charge induction from the surrounding medium fails to properly describe the internal charge redistributions upon hydrogen bonding.

Efficiency of different extraction solvent mixtures used in analyses of aflatoxins from a certified peanut meal reference material

Four analytical methods with different extraction solvent mixtures were used to compare the efficiency of the extraction step in the analysis of aflatoxins from a reference material with a certified value of 206 +/- 13 microg aflatoxin B(1) kg(-1). The extraction mixtures used were chloroform-water (100 + 10), acetonitrile-water (60 + 40), acetone-water (85 + 15) and methanol-water (80 + 20). The analytical values determined from the extraction mixtures after correction for recovery were 211, 204, 163 and 120 microg kg(-1), respectively. The small amounts of aflatoxin B(2) in the reference material followed the same pattern. The selection of extraction solvent mixture is very important for achieving the true value and that correction for recovery does not always fully compensate for getting the correct analytical value.

Ochratoxin A in raisins and currants: basic extraction procedure used in two small marketing surveys of the occurrence and control of the heterogeneity of the toxins in samples

A basic extraction procedure for analysis of ochratoxin A (OTA) in currants and raisins is described, as well as the occurrence of OTA and a control of heterogeneity of the toxin in samples bought for two small marketing surveys 1999/2000 and 2001/02. Most samples in the surveys were divided into two subsamples that were individually prepared as slurries and analysed separately. The limit of quantification for the method was estimated as 0.1 microg kg(-1) and recoveries of 85, 90 and 115% were achieved in recovery experiments at 10, 5 and 0.1 microg kg(-1), respectively. Of all 118 subsamples analysed in the surveys, 96 (84%) contained ochratoxin A at levels above the quantification level and five samples (4%) contained more than the European Community legislation of 10 microg kg(-1). The OTA concentrations found in the first survey were in the range < 0.1-19.0 microg kg(-1) with a median concentration of 0.9 microg kg(-1). In the 2001/02 study, the range was < 0.1-34.6 microg kg(-1) with a median of 0.2 microg kg(-1). Big differences were often achieved between individual subsamples of the original sample, which indicate a wide heterogeneous distribution of the toxin. Data from the repeatability test as well as recovery experiments from the same slurries showed that preparation of slurries as described here seemed to give a homogeneous and representative sample. The extraction with the basic sodium bicarbonate-methanol mixture used in the surveys gave similar or somewhat higher OTA values on some samples tested in a comparison with a weak phosphoric acid water-methanol extraction mixture.

Effect of work with visual display units on musculo-skeletal disorders in the office environment

BACKGROUND

The increase in computer and mouse use has been associated with an increased prevalence of disorders in the neck and upper extremities. Furthermore, poor workstation design has been associated with an increased risk of developing these symptoms. Aim The aims of this study were (i) to estimate the prevalence of musculo-skeletal disorders among full-time visual display unit (VDU) users; (ii) to examine how the prevalence varies by work environment; and (iii) to explore the association with work factors.

METHOD

A survey was carried out on the effect of work with VDUs on musculo-skeletal disorders in workers in the office environment of 56 workplaces. Office workers (n = 298), customer service workers (n = 238) and designers (n = 247) were studied.

RESULTS

For all the occupations combined, the 12 month prevalences of musculo-skeletal symptoms in the neck, shoulders, elbows, lower arms and wrists, and fingers were 63, 24, 18, 35 and 16%, respectively. The study indicated that musculo-skeletal pain is common among computer workers in offices. There was no strong association between the duration of computer work and pain or between the duration of mouse use and pain, but workers' perception of their workstation as being poor ergonomically was strongly associated with an increased prevalence of pain.

CONCLUSIONS

Musculo-skeletal symptoms are common, but the duration of daily keyboard and mouse use had no connection with musculo-skeletal symptoms. Instead, more consideration should be paid to the ergonomics of workstations, the placing of the mouse, the postures of the upper extremities and the handling of the mouse.

Bonding of saturated hydrocarbons to metal surfaces

The adsorption of octane on Cu(110) was studied by x-ray absorption and x-ray emission spectroscopy, in combination with spectrum calculations in the framework of density functional theory, as a model system for alkane adsorption on transition metals. Significant electron sharing between the adsorbate and metal surface and involvement of both bonding and antibonding C-H molecular orbitals in the molecule-metal bond was found. The calculations were extended to the case of octane adsorbed on Ni(110), and the position of the metal d band was found to be important for the bonding. The results were generalized to show that this is important for the efficiency as an alkane dehydrogenation catalyst.

Structure and bonding of water on Pt(111)

We address the adsorption of water on Pt(111) using x-ray absorption, x-ray emission, and x-ray photoelectron spectroscopy along with calculations in the framework of density functional theory. Using the direct relationship between the electronic structure and adsorbate geometry, we show that in the first layer all the molecules bind directly to the surface and to each other through the in-layer H bonds without dissociation, creating a nearly flat overlayer. The water molecules are adsorbed through alternating metal-oxygen (M-O) and metal-hydrogen (M-HO) bonds.

Inguinal hernia after radical retropubic prostatectomy for prostate cancer: a study of incidence and risk factors in comparison to no operation and lymphadenectomy

PURPOSE

The incidence, mechanisms and risk factors of inguinal hernia after radical retropubic prostatectomy are sparsely elucidated in the literature. We determined the rate of inguinal hernia after radical retropubic prostatectomy and compared it to the incidence in patients with prostate cancer who did not undergo operation or underwent only pelvic lymph node dissection.

MATERIALS AND METHODS

We followed 375, 184 and 65 men who underwent radical retropubic prostatectomy plus pelvic lymph node dissection, pelvic lymph node dissection only and no surgery with respect to inguinal hernia for a mean of 39, 47 and 45 months, respectively. The prostatectomy group was also evaluated in regard to the potential risk factors of previous hernia surgery and post-prostatectomy anastomotic stricture.

RESULTS

The incidence of hernia was 13.6%, 7.6% and 3.1% in the prostatectomy, lymph node dissection and unoperated group, respectively. The difference was statistically significant in the prostatectomy and unoperated groups according to the Mantel-Cox log rank test and Cox proportional hazards rate. Previous hernial surgery and post-prostatectomy anastomotic stricture were more common in patients with an inguinal hernia after prostatectomy.

CONCLUSIONS

The incidence of inguinal hernia is clearly increased in men who have undergone radical retropubic prostatectomy plus pelvic lymph node dissection compared with those who undergo no surgery for prostate cancer. Inguinal hernia appears to develop more often in men with prostate cancer who undergo radical retropubic prostatectomy and pelvic lymph node dissection than in those who undergo pelvic lymph node dissection only. While surgical factors trigger hernial development, previous hernial surgery and post-prostatectomy anastomotic stricture may be important risk factors. In fact, the latter may largely explain the difference in the incidence of inguinal hernia in our lymph node dissection and prostatectomy groups. Prophylactic surgical procedures must be evaluated to address this problem.

Electronic structure effects from hydrogen bonding in the liquid phase and in chemisorption: an integrated theory and experimental effort

A closely integrated theoretical and experimental effort to understand chemical bonding using X-ray spectroscopic probes is presented. Theoretical techniques to simulate XAS (X-ray absorption spectroscopy), XES (X-ray emission spectroscopy), RIXS (resonant inelastic X-ray scattering) and XPS (X-ray photoelectron spectroscopy) spectra have been developed and implemented within a density functional theory (DFT) framework. In combination with new experimental techniques, such as high-resolution XAS on liquid water under ambient conditions and XES on complicated surface adsorbates, new insight into e.g. hydrogen-bonded systems is obtained. For the (3x2) overlayer structure of glycine/Cu(110), earlier work has been extended to include adsorbate-adsorbate interactions. Structures are optimized for large cluster models and for periodic boundary conditions. It is found that specific features in the spectra arise from hydrogen-bonding interactions, which thus have important effects at the molecular-orbital level. XAS on liquid water shows a pronounced pre-edge feature with significant intensity, while the spectrum of ice shows only little intensity in this region. Theoretical spectrum calculations, based on instantaneous structures obtained from molecular-dynamics (MD) simulations, show that the pre-edge feature in the liquid is caused by water molecules with unsaturated hydrogen bonding. Some aspects of the theoretical simulations will be briefly discussed.

How carbon monoxide adsorbs in different sites

The interplay between the electronic and the geometric structure of adsorbates is of fundamental importance for the understanding of many surface phenomena. Using x-ray emission spectroscopy and ab initio cluster calculations, this issue has been investigated in unprecedented detail for CO adsorption in different adsorption sites. The investigation establishes pi bonding and sigma repulsion, both increasing with the number of coordinated metal atoms. The two contributions partly compensate each other, leading to only small differences in adsorption energies for the different adsorption sites despite very large variations in the electronic structure.