Bone mineral density after exercise training in patients with chronic kidney disease stages 3 to 5: a sub-study of RENEXC-a randomized controlled trial

Background

We evaluated the effects of 12 months of exercise training on bone mineral density (BMD) in patients with chronic kidney disease (CKD) stages 3-5 not on kidney replacement therapy (KRT).

Methods

A total of 151 patients were randomized to 12 months of either balance or strength training, both together with endurance training. Some 112 patients completed and 107 (69 men, 38 women) were analysed, with a mean age 66 ± 13.5 years and 31% having diabetes. The exercise training was self-administered, prescribed and monitored by a physiotherapist. Total body, hip and lumbar BMD, T score and Z score were measured at baseline and after 12 months using dual energy X-ray absorptiometry.

Results

Both groups showed increased physical performance. The prevalence of osteoporosis and osteopenia was unchanged. The strength group (SG) decreased total body BMD (P < .001), the balance group (BG) increased total body T score (P < .05) and total body Z score (P < .005). Total body ΔT score was negative in the SG and unchanged in the BG (P < .005). Total body ΔZ score was negative in the SG and positive in the BG (P < .001). The proportion of progressors measured by ΔT (P < .05) and ΔZ scores (P < .05) was significantly lower in the BG compared with the SG. In multivariate logistic regression analysis, belonging to the BG was the only factor with a lower risk of deterioration of total body BMD, T and Z scores.

Conclusions

Twelve months of balance training together with endurance training seemed to be superior to strength training in maintaining and improving BMD in patients with CKD not on KRT.

Central venous stenosis after subclavian versus internal jugular dialysis catheter insertion (CITES) in adults in need of a temporary central dialysis catheter: study protocol for a two-arm, parallel-group, non-inferiority randomised controlled trial

BACKGROUND

The right internal jugular vein is currently recommended for temporary central dialysis catheters (tCDC) based on results from previous studies showing a lower incidence of central vein stenosis compared to the subclavian vein. Data is however conflicting, and there are several advantages when the subclavian route is used for tCDCs. This prospective, controlled, randomised, non-inferiority study aims to compare the incidence of post-catheterisation central vein stenosis between the right subclavian and the right internal jugular routes.

METHODS

Adult patients needing a tCDC will be included from several hospitals and randomised to either subclavian or internal jugular vein catheterisation with a silicone tCDC. Inclusion continues until 50 patients in each group have undergone a follow-up CT venography. The primary outcome is the incidence of post-catheterisation central vein stenosis detected by a CT venography performed 1.5 to 3 months after removal of the tCDC. Secondary outcomes include between-group comparisons of (I) the patients' experience of discomfort and pain, (II) any dysfunction of the tCDC during use, (III) catheterisation success rate and (IV) the number of mechanical complications. Furthermore, the ability to detect central vein stenosis by a focused ultrasound examination will be evaluated using the CT venography as golden standard.

DISCUSSION

The use of the subclavian route for tCDC placement has largely been abandoned due to older studies with various methodological issues. However, the subclavian route offers several advantages for the patient. This trial is designed to provide robust data on the incidence of central vein stenosis after silicone tCDC insertion in the era of ultrasound-guided catheterisations.

TRIAL REGISTRATION

Clinicaltrials.gov; NCT04871568. Prospectively registered on May 4, 2021.

MO552: Self-Administered Exercise and Bone Mineral Density in Patients With Chronic Kidney Disease: A Substudy of Renexc—A Randomized Controlled Trial

BACKGROUND AND AIMS

The aim of the study was to evaluate the effects of 12 months self-administered exercise training on bone mineral density (BMD) in non-dialysis-dependent patients with chronic kidney disease stages 3–5.

METHOD

In this single-centre, randomized controlled trial, 151 patients were allotted 60 minutes of endurance training in combination with 90 minutes of either balance or strength training. The exercise was prescribed and monitored by a physiotherapist and performed at home or a gym.

Total body-, hip- and lumbar BMD (g/m2), T-score and Z-score were measured at baseline (T0) and after 12 months (T12) using dual-energy X-ray absorptiometry (DEXA).

A total of 112 patients completed the study. Of these, five patients were excluded from analysis because they missed either the T0 or T12 DEXA evaluation.

To evaluate between-group changes after the study period delta BMD, delta T-score and delta Z-score values (T12 value–T0 value) were calculated. These results were also used to define progressors and non-progressors.

Statistical analyses were performed using SPSS for Windows 24. Statistical significance was assessed using Student's t-test, paired-sample t-test, Mann–Whitney or Wilcoxon matched-pairs signed-rank tests depending on normality of data distribution. The two-tailed chi-squared test was used to compare categorical variables. Values are given as mean ± SD or median (min-max). A P-value &lt; 0.05 was accepted as the level of significance.

RESULTS

A total of 107 patients [69 men, 38 women; age 66 ± 13.5 years, measured glomerular filtration rate (GFR) 22 ± 8 mL/min/1.73 m2] were analysed. There were 50 patients (34 men, 16 women) in the strength group and 57 (35 men, 22 women) in the balance group.

After 12 months of training the whole group showed a statistically significant decrease in hip BMD [0.886 (0.479–1.922) T0 versus 0.873 (0.521–2.045) T12, P = 0.002], hip T score [−1.177 ± 1.419 T0 versus − 1.4 (−4.0 to 6.6) T12, P = 0.049] and total body BMD (1.156 ± 0.508 T0 versus 1.149 ± 0.164 T12, P = 0.032).

When data were analysed separately within each group, the strength group showed a decrease in total body BMD (1.152 ± 0.151 T0 versus 1.141 ± 0.153 T12, P = 0.001). Changes in total body T-score and Z-score did not reach the level of significance (T-score − 0.392 ± 1.56 T0 versus − 0.484 ± 1.56 T12, P = 0.138; Z-score 0.07 ± 1.19 T0 versus − 0.012 ± 1.21 T12, P = 0.052). The balance group showed a statistically significant increase after 12 months training in total body T-score (−0.312 ± 1.659 T0 and − 0.196 ± 1.707 T12, P = 0.035) and total body Z-score [0.05 ± 1.626 T0 and 0.4 (−5.1 to 6.8) T12, P = 0.003] but not in total body BMD [1.16 ± 0.151 T0 versus 1.123 (0.668 to 1.818) T12, P = 0.135].

Delta total body T-score was negative in the strength group [−0.10 (−1.0 to 2.1) and unchanged in the balance group 0.00 (−0.60 to 1.00), showing a significant between-group difference (P = 0.005)]. Delta total body Z-score was negative in the strength group (−0.092 ± 0.430) and positive in the balance group (0.1158 ± 0.403) showing a significant between-group difference (P = 0.001). Moreover, the proportion of progressors was higher in the strength group as shown by the delta total body T-score (60%) strength versus (40%) balance group (P = 0.006) and delta total body Z-score (61%) and (40%) respectively (P = 0.029).

CONCLUSION

Balance—in combination with endurance training seemed to be superior to strength—in combination with endurance training in preserving and even improving bone health. The 12 months of balance training resulted in an increase in total body T-score and Z-score, respectively. The strength group showed a decrease in total body BMD after 12 months of training. Moreover, when comparing the delta values there were significant between-group effects with the balance group showing an unchanged T-score in comparison with the strength group's decreased T-score and a positive Z score in comparison with the strength group's negative value. Finally, a greater proportion of participants in the strength group were classified as progressors with a deterioration of bone health.

MO601: Using the Borg Scale for Exercise Prescription and for Monitoring Self-Administered Aerobic Endurance Exercise is Safe and Effective for Patients with CKD

BACKGROUND AND AIMS

Decline in physical function starts relatively early in the course of CKD and has an impact on activities in daily life, such as walking capacity. Several studies with supervised centre-based exercise training as well as studies with self-administered home-based exercise have shown improvement in walking capacity. However, monitoring intensity and safety is important when exercise is self-administrated. There are to our knowledge no studies evaluating the Borg RPE scale as a tool to prescribe exercise intensity and as an instrument for self-monitoring exercise training in patients with CKD.

The aims of this study were to examine the adherence, performance, and safety of self-administered aerobic endurance exercise when exercise intensity was prescribed and self-monitored with the Borg rating of perceived exertion (RPE) scale in non-dialysis dependent patients with CKD stages 3–5, and the relationship between performed exercise and change in walking distance.

METHOD

In this sub-study of the RENEXC trial 147 patients (97 men, 50 women), irrespective of age and comorbidities, were included. Mean age was 66 ± 14 years and the mean measured GFR 22 ± 8 mL/min/1.73 m2. Twelve months of aerobic endurance exercise (60 min/week) was combined with either balance or strength exercises (90 min/week). All exercise was individually prescribed by a research physiotherapist, based on each patient's baseline tests. The aerobic endurance exercise was prescribed to have a level of intensity between 13 (somewhat strenuous) to 15 (strenuous) using the Borg RPE scale. Exercise was self-monitored and recorded in a training diary. Follow up was performed by the physiotherapist through phone contact. The 6-min walk test was measured at baseline and after 4, 8 and 12 months of exercise.

RESULTS

Hundred patients completed the study. Our training program had an excellent level of adherence, at 12 months 80% of the patients reported performed exercise and 74% performed exercise within the prescribed intensity. The mean intensity of the aerobic endurance exercise was rated at 13 ± 1 on the Borg RPE scale. Median duration of aerobic endurance exercise was 56 (33–109) minutes/week. However, there was a wide range of weekly duration where patients with a low walking distance at baseline performed less minutes of exercise/week (P = 0.039). Irrespective of weekly duration the patients were able to perform exercise within the prescribed interval of RPE 13–15. No exercise related incidents were reported. Walking distance improved significantly by mean 30 ± 56 meters (P &lt; 0.001). There was no correlation between weekly duration of exercise and change in walking distance, indicating that deconditioned patients with a short baseline walking distance can increase walking capacity when performing a shorter weekly duration of somewhat strenuous to strenuous exercise, whereas patients with a higher baseline walking distance must perform a longer duration of exercise to increase walking capacity.

CONCLUSION

The Borg RPE scale is a useful, acceptable, simple and safe method for prescribing and monitoring intensity of self-administered aerobic endurance exercise in patients with CKD. A RPE of somewhat strenuous to strenuous improved walking capacity in deconditioned patients with CKD, within a wide range of weekly duration of exercise.

Muscle mass and plasma myostatin after exercise training: a substudy of Renal Exercise (RENEXC)-a randomized controlled trial

BACKGROUND

Sarcopenia increases as renal function declines and is associated with higher morbidity and mortality. Myostatin is a negative regulator of muscle growth. Its expression in response to exercise is unclear. In this prespecified substudy of the Renal Exercise (RENEXC) trial, we investigated the effects of 12 months of exercise training on sarcopenia, muscle mass and plasma myostatin and the relationships between physical performance, muscle mass and plasma myostatin.

METHODS

A total of 151 non-dialysis-dependent patients (average measured glomerular filtration rate 23 ± 8 mL/min/1.73 m2), irrespective of age or comorbidity, were randomly assigned to either strength or balance in combination with endurance training. Body composition was measured with dual-energy X-ray absorptiometry. Plasma myostatin was analysed using enzyme-linked immunosorbent assay kits.

RESULTS

After 12 months, the prevalence of sarcopenia was unchanged, leg and whole-body lean mass increased significantly in the balance group and was unchanged in the strength group. Whole fat mass decreased significantly in both groups. There were no significant between-group differences in sarcopenia or body composition. Plasma myostatin levels increased significantly in both groups, with a significant difference in favour of the strength group. Plasma myostatin was significantly positively related to muscle mass and physical performance at baseline, but these relationships were attenuated after 12 months.

CONCLUSIONS

Exercise training seems to be effective in preventing sarcopenia and maintaining muscle mass in non-dialysis-dependent patients with chronic kidney disease (CKD). However, the role of plasma myostatin on muscle mass and physical performance in patients with CKD warrants further study.

Twelve months of exercise training did not halt abdominal aortic calcification in patients with CKD - a sub-study of RENEXC-a randomized controlled trial

BACKGROUND

Arteriosclerosis is prevalent in patients with chronic kidney disease (CKD). Our aims were to investigate (1) the effects of 12 months of either balance- or strength- both in combination with endurance training on abdominal aortic calcification (AAC); on some lipids and calcific- and inflammatory markers; and (2) the relationships between the change in AAC score and these markers in non-dialysis dependent patients with CKD stages 3 to 5.

METHODS

One hundred twelve patients (mean age 67 ± 13 years), who completed 12 months of exercise training; comprising either balance- or strength training, both in combination with endurance training; with a measured glomerular filtration rate (mGFR) 22.6 ± 8 mL/min/1.73m2, were included in this study. AAC was evaluated with lateral lumbar X-ray using the scoring system described by Kauppila. Plasma fetuin-A, fibroblast growth factor 23 (FGF23) and interleukin 6 (IL6) were measured with Enzyme-linked immunosorbent assay (ELISA) kits.

RESULTS

After 12 months of exercise training, the AAC score increased significantly in both groups; mGFR and lipoprotein (a) decreased significantly in both groups; parathyroid hormone (PTH) and 1,25(OH)2D3 increased significantly only in the strength group; fetuin-A increased significantly only in the balance group. Plasma triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, FGF23, phosphate, calcium, IL6, C-reactive protein (CRP), albumin were unchanged. The increase in AAC score was positively related to ageing and the levels of baseline triglycerides and lipoprotein (a).

CONCLUSIONS

Exercise training did not prevent the progression of AAC; it might have contributed to the reduced levels of lipoprotein (a) and unchanged levels of calcific- and inflammatory markers in these patients with non-dialysis dependent CKD. Hypertriglyceridemia, high levels of lipoprotein (a) and ageing emerged as longitudinal predictors of vascular calcification in these patients.

TRIAL REGISTRATION

NCT02041156 at www.ClinicalTrials.gov. Date of registration: January 20, 2014. Retrospectively registered.

SO068EFFECTS OF BASELINE PHYSICAL FUNCTION AND 12 MONTHS EXERCISE TRAINING ON SURVIVAL IN PATIENTS WITH NON DIALYSIS DEPENDENT CHRONIC KIDNEY DISEASE

Background and Aims

Low physical function is associated with increased mortality in patients on dialysis. Observational studies have shown an association between self-reported physical activity and survival in patients with chronic kidney disease (CKD). It is unclear whether exercise training can affect survival in patients with CKD. The purpose of this study was to investigate, whether level of physical function and exercise training, respectively, affect survival in patients with non-dialysis dependent CKD stages 3-5.

Method

The patients studied had participated in the RENEXC study comprising 12 months of endurance training in combination with either strength- or balance training. In this study the whole group was analyzed as both groups had improved their physical function with no between group differences. Physical function at baseline and after 12 months was assessed with a battery of tests. Patients were divided into 4 groups for each test: improved physical function by &gt;10 %, no improvement, did not complete 12 months of exercise training and missing data. Effects of physical function at baseline and improvement in physical function after 12 months of exercise training on survival were analyzed using univariate and multivariate Cox regression analyses. Multivariate analyses were adjusted for age, sex, co-morbidity, time on dialysis and time as transplanted.

Results

This study comprised 151 patients, mean age 66±14 years, 65% men, measured GFR 22.5±8.2 ml/min/1.73 m2. Median follow-up was 60 months.

Physical function at baseline was associated with a significantly better survival in univariate Cox regression analysis in the following tests: 6 Minute Walk Test (6MWT), handgrip strength right, functional reach and 30 seconds Sit-To-Stand (30s-STS). The decline in hazard ratio (HR) per unit in each test was 0.5 % in the 6MWT, 2.9 % in handgrip strength, 6.4 % in functional reach and 10.8 % in 30s-STS. Multivariate analyses showed that only 6MWT and 30s-STS were significantly related to survival. The decline in hazard ratio (HR) per unit in the multivariate analyses was 0.4 % in the 6MWT (HR 0.996, CI 0.994-0.998) and 5.7 % in 30s-STS (HR 0.943, CI 0.892-0.996).

Patients who completed 12 months of exercise training and improved their results by 10 % or more showed a significantly better survival compared with patients who completed 12 months of exercise training but failed to improve by at least 10 % in the following tests in the univariate analyses: handgrip strength right and left, isometric quadriceps strength left and 30s-STS. There was also a significantly better survival in the group that improved compared with the group that did not complete 12 months of exercise in the 6MWT, handgrip strength right and left, isometric quadriceps strength left and 30s-STS. In the multivariate analyses there were no significant differences between the group that improved and the group that did not improve in any of the physical function tests. The significant differences between the group that improved and the group that did not complete remained in the following tests: handgrip strength right (HR 7.83, CI 2.10-29.2) and left (HR 3.95, CI 1.31-11.9), isometric quadriceps strength left (HR 3.94, CI 1.78-8.74) and 30s-STS (HR 3.50, CI 1.58-7.77). The difference between the group that improved and the group that did not complete the training became significant in functional reach (HR 4.22, CI 1.99-8.94) and isometric quadriceps strength right (HR2.80, CI 1.35-5.80).

Conclusion

After adjustment for age, sex, co-morbidity, time on dialysis and time as transplanted overall endurance and muscular endurance at baseline were associated with a better survival. Patients who improved muscle strength, muscular endurance and balance showed a better survival compared with those who did not complete the study. There were no statistically significant differences between those who improved their physical function by at least 10% compared with those who did not.

Sarcopenia and relationships between muscle mass, measured glomerular filtration rate and physical function in patients with chronic kidney disease stages 3-5

Background

Sarcopenia and poor physical function are common in patients with chronic kidney disease (CKD). Our aim was to investigate the relationships between muscle mass and measured glomerular filtration rate (GFR) and between muscle mass and strength and balance, respectively, in patients with CKD stages 3-5.

Methods

This is a baseline data analysis of a randomized controlled clinical trial. A total of 148 adult patients with an estimated GFR <30 mL/min/1.72 m2, not on renal replacement therapy, irrespective of the number of comorbidities were included from the Department of Nephrology, Skåne University Hospital, Lund, from 2011 to 2016. Body composition was measured by dual-energy X-ray absorptiometry (DEXA). GFR was measured by iohexol clearance. Balance was measured by functional reach and the Berg balance test and strength by handgrip strength and isometric quadriceps strength.

Results

Measured GFR ranged from 8 to 55 mL/min/1.73 m2. Lean mass (P < 0.05), fat mass (P < 0.05), appendicular skeletal muscle (P < 0.001) and appendicular skeletal muscle index (P < 0.05) were associated with GFR. Functional reach was associated with leg lean mass (P < 0.05) and the Berg balance test score was associated with trunk lean mass (P < 0.05). Handgrip strength was associated with arm lean mass (P < 0.001). Isometric quadriceps strength was associated with leg lean mass (P < 0.001). More men (44%) suffered from low muscle mass than women (22%), whereas more women (36%) suffered from low muscle strength than men (26%). However, when combining both, men (16%) suffered from sarcopenia to a greater extent than women (8%).

Conclusions

Among patients with CKD stages 3-5, loss of lean body mass, especially appendicular skeletal muscle, was significantly related to GFR decline. Two important markers of physical function, balance and strength, were significantly related to muscle mass. Moreover, men were more prone to sarcopenia than women during kidney function decline.

Randomized Controlled Trial of Exercise in CKD-The RENEXC Study

Introduction

Home-based, clinically feasible trials in non-dialysis-dependent patients with chronic kidney disease (CKD) are sparse. We compared the effects of 2 different exercise training programs on physical performance, and measured glomerular filtration rate (mGFR) and albuminuria level in patients with CKD stages 3 to 5.

Methods

This is a single-center, randomized controlled trial (RCT) comprising 151 patients (mGFR: 22 ± 8 ml/min per 1.73 m²; age 66 ± 14 years) randomized to either balance or strength training. Both groups were prescribed 30 minutes of exercise per day for 5 days per week for 12 months, comprising 60 minutes per week of endurance training and 90 minutes per week of either strength or balance exercises. The exercises were individually prescribed, and the intensity was monitored with Borg's rating of perceived exertion (RPE).

Results

There were no treatment differences for any of the primary outcomes measuring physical performance. The strength and balance groups showed significantly increased effect sizes after 12 months for the following: walking (31 m and 24 m, P < 0.001) and the 30-second sit-to-stand test (both: 1 time, P < 0.001); quadriceps strength (right/left: strength 1.2/0.8 kg*m, P < 0.003; balance 0.6/0.9, P < 0.01); functional reach (both: 2 cm, P < 0.01); and fine motor skills (open/closed eyes, right/left, both: between 0.3 and 4 seconds faster, P < 0.05). After 12 months, there was a significant treatment difference for albuminuria (P < 0.02), which decreased by 33% in the strength group. In both groups, mGFR declined by 1.8 ml/min per 1.73 m².

Conclusion

Our primary hypothesis that strength training was superior to balance training was not confirmed. Within groups, 12 months of exercise training resulted in significant improvements in most measures of physical performance. Measured GFR declined similarly in the 2 groups. The strength group showed a significant decrease in albuminuria.

Comparing effects of 4 months of two self-administered exercise training programs on physical performance in patients with chronic kidney disease: RENEXC - A randomized controlled trial

Background

Exercise training is recommended to patients with chronic kidney disease (CKD). However, the level of evidence is still low. This randomized controlled trial (RCT) compared two different and self-administered exercise training programs in a representative CKD population.

Methods

This single centre RCT included 151 non-dialysis dependent CKD patients, irrespective of age and comorbidity. Self-administered exercise training of 150 minutes per week was prescribed for 4 months and consisted of 60 minutes endurance training in combination with 90 minutes of either strength or balance training (strength versus balance group). Overall endurance (6-minute walk-test (6-MWT), stair climbing), muscular endurance (30-seconds sit-to-stand (30-STS), heel rises and toe lifts, handgrip (HGS) and isometric quadriceps (IQS) strength, balance (functional reach (FR) and Berg´s balance scale (BBS)) and fine motor skills (Moberg´s picking up test (MPUT)) were measured at baseline and after 4 months. Intention to treat analyses with mixed models was used.

Results

53 women and 98 men, mean age 66 ± 14: range 19 to 87 years, eGFR 20 ± 7: range 8 to 48 ml/min/1.73m² participated. The strength group (n = 76) improved significantly in 6-MWT, stair climbing, 30-STS, heel rises right and left, toe lifts right, IQS right and left, and MPUT with closed eyes with the right and left hand. The balance group (n = 75) improved significantly in heel rises right and left, IQS left, BBS and left-handed MPUT with open and closed eyes. A significant effect between the groups was found for IQS right.

Conclusions

Two different exercise training programs, consisting of endurance in combination with either strength or balance exercise training, improved or maintained overall endurance, muscular strength and endurance, balance and fine motor skills after 4 months of 150 minutes/week self-administered exercise training in a representative CKD population, regardless of age and comorbidity.

Relationship between declining glomerular filtration rate and measures of cardiac and vascular autonomic neuropathy

AIM

Cardiac and vascular autonomic neuropathy contributes to increased morbidity and mortality in patients with chronic kidney disease. The aim of this study was to analyze the effects of a decline in glomerular filtration rate (GFR) on heart rate variability (HRV) and nocturnal blood pressure dipping.

METHODS

This cross-sectional study comprises 124 patients (46 women, 78 men; age 66 ± 14 years) with chronic kidney disease (CKD) 3-5, not on renal replacement therapy. GFR was measured with iohexol clearance, HRV with 24 h Holter electrocardiogram (ECG) and nocturnal dipping with 24 hour ambulatory blood pressure.

RESULTS

The GFR was 22.5 ± 8.5 mL/min per 1.73 m² . The main finding was a significant curvilinear association between the 24 h standard deviation of NN interval (24SDNN) in the HRV analysis and GFR (P = 0.01), logGFR (P = 0.006), diabetes mellitus (P = 0.05) and beta blocker treatment (0.03), respectively. The effect of diabetes mellitus on 24SDNN corresponded to a decline in GFR from 30 to 12 mL/min per 1.73 m² . There were significant curvilinear associations between systolic nocturnal dipping (P = 0.02) and diastolic nocturnal dipping (P = 0.05), respectively, and diabetes mellitus but not with GFR or logGFR.

CONCLUSION

In conclusion, cardiac sympathetic overdrive and decreased vagal control appear during CKD 4 and 5. The association with GFR is curvilinear. Diabetes mellitus was significantly associated with both cardiac and vascular autonomic neuropathy, as measured by heart rate variability and nocturnal blood pressure dipping, respectively. Knowing that arrhythmias, often due to sympathetic hyperactivity, are an important cause of sudden death in the dialysis population, this study contributes important knowledge on possible intervention thresholds.

Dynamics of coupled light waves and electron-acoustic waves

The nonlinear interaction between coherent light waves and electron-acoustic waves in a two-electron plasma is considered. The interaction is governed by a pair of equations comprising a Schrödinger-like equation for the light wave envelope and a driven (by the light pressure) electron-acoustic wave equation. The newly derived nonlinear equations are used to study the formation and dynamics of envelope light wave solitons and light wave collapse. The implications of our investigation to space and laser-produced plasmas are pointed out.

Secretion of cytokines by uroepithelial cells stimulated by Escherichia coli and Citrobacter spp

Urinary tract epithelial cells (T 24/83) are able to express interleukin (IL)-6, IL-8, platelet-derived growth factor (PDGF) and tumour necrosis factor-alpha, but not IL-1 beta, IL-2, IL-4 and IL-10 in response to an infection with uropathogenic bacteria. The process of cytokine secretion is time dependent, with a significant increase in the cytokine activity after 60 min. The expression of virulence factors of the bacteria does not seem to play a role. The interaction between bacterial products (e.g. lipopolysaccharide) and/or bacterial adhesion mediated by adhesins and specific receptor molecules of cell surfaces may be responsible for the activity of mediator protein expression in the epithelial cells. The release of PDGF and IL-8 was found to be higher when due to Escherichia coli HB 101 (rough form) than that caused by other bacterial strains. Citrobacter CB 3009 provoked the highest level of IL-6. The PDGF level correlated significantly with IL-6 and IL-8 values (P<0.001). There was a significant correlation between the time-dependent release of IL-6 and IL-8 (P<0.05). In epithelial cytokine response to bacterial infection, the reaction of the epithelial cells may modify themselves (e.g. internalization of bacteria) and the immuno-regulatory processes that are caused by infection and responsible for parenchymal injury.

A preliminary investigation of mesoionic xanthine analogues as inhibitors of platelet aggregation

A series of mesoionic xanthines (e.g. mesoionic thiazolopyrimidines, 3, and thiadiazolopyrimidines, 5) and related analogues were examined as inhibitors of human platelet aggregation. Appropriately substituted compounds were found to fully inhibit platelet aggregation, and anhydro-(6-ethyl-8-isopentyl-7-oxo-5-hydroxy-1,3,4-thiadiazolo[3,2 -a]pyrimidinium hydroxide) (5b) was 40 times more potent than the structurally related xanthine theophylline (1). Gel filtration studies suggest that compound 5b irreversibly inhibits aggregation and this might be due to its ability to act as a latent acylation agent.

Evaluation of AL-05712 and AL-05741 as thioltransferase mimics for the prevention and recovery of pre-cataractous changes in lens

It has been previously shown that during the aging process, the human eye lens accumulates protein-glutathione mixed disulfides (PSSG) and that the reduced glutathione (GSH) level drops. These changes become even more pronounced during cataractogenesis. In this report, the ability of AL-05712 and AL-05741 to lower PSSG and elevate GSH in three separate model systems was evaluated. AL-05741 was able to decrease PSSG in the cell-free system by over 30% at a concentration of 0.1 mM. AL-05712, the ester form of AL-05741, decreased mixed disulfides by about 8% in the same system in the absence of any cellular esterases. Both compounds could partially inhibit the loss of GSH seen in the H2O2 control in cultured rat lenses and in addition, the accumulation of PSSG was substantially decreased. Human lenses incubated in AL-05712 showed a significant elevation of cortical GSH and a decrease in PSSG in three of four sets of cultured human lenses.