Peritoneal dialysis in children under 5 years of age

The aim of this study was to examine the effect of intensive practice in table tennis on perceptual coincident timing. The main question was whether the perceptual demands encountered in fast ball sports produce modifications of the perceptual visual system. Expert table tennis players and novices were compared in a perceptual task which consisted of estimating, by pressing a key, the arrival of a moving stimulus at a target. The stimulus, which was presented either at constant velocity or at constant deceleration, reproduced as closely as possible the natural visual demands encountered in table tennis. The difference between the time of response and the time of arrival of the stimulus at a target position was measured over 40 trials for each of the 16 participants. The results showed no effect of expertise under the constant-velocity condition but an effect under the decelerative condition, indicating that experts were less trajectory-dependent than novices. This result was interpreted as reflecting a better adaptation of the perceptual system of experts to the constraints encountered during table tennis and specifically to the perceptual demands resulting from varied and decelerated ball trajectories. Finally, some limitations of the coincidence anticipation procedure are highlighted, concerning its use in practical settings for evaluating athletes or detecting sport talents, and the need for the simulation conditions during testing to reproduce as closely as possible the perceptual demands of real life is discussed.     

Peritoneal protein loss in children with nephrotic syndrome during peritoneal dialysis

BACKGROUND: The passage of proteins across the glomerular filtration barrier is mainly determined by the size of the protein. In nephrotic syndrome (NS) the glomerular permselectivity is affected, causing proteinuria. Some authors suggest the existence of a generalized basement membrane defect. The permeability characteristics of the peritoneal basement membrane in children with NS are not known. METHODS: The transperitoneal transport of proteins with a different molecular weight (beta2-microglobulin MW 11800 D, albumin MW 69000 D, IgG MW 160000 D, and alpha2-macroglobulin MW 820000 D) was studied in a study group (group A) consisting of six stable nephrotic children (three with glomerulosclerosis and three with congenital nephrotic syndrome, one of them with mesangial sclerosis) and compared to a control group (group B) consisting of eight stable children on peritoneal dialysis. After a dwell of 6 h with Dianeal 1.36% dialysate and serum samples were collected. For each patient the dialysate to plasma (D/P) ratios of the four proteins were calculated. The D/P ratios of the nephrotic patients in group A were compared to the D/P ratios of the patients in the control group B. Data were expressed as mean +/- SD. RESULTS: The values for the D/P ratios (in percentage) of beta2-microglobulin, albumin, IgG and alpha2-macroglobulin in group A were 19.6+/-9.9, 2.7+/-1.7, 1.6+/-0.9, and 0.5+/-0.4, compared to 24.9+/-10.2, 4.0+/-2.3, 2.2 +/- 1.2, and 0.7 +/- 0.3 in the control group B. The ratios were plotted against MW on a double logarithmic scale. In all patients a linear relationship between molecular weight and D/P ratio of the proteins was obtained. The D/P ratios of the study group did not differ significantly from the control group. CONCLUSION: We conclude that the size selectivity of the capillary permeability is not affected in the peritoneal membrane in children with NS due to glomerulosclerosis and congenital nephrotic syndrome.     

Manganese toxicity in children receiving long-term parenteral nutrition

BACKGROUND: In patients receiving long-term parenteral nutrition (PN), cholestatic disease and nervous system disorders have been associated with high blood concentrations of manganese. In such patients, the normal homoeostatic mechanisms of the liver and gut are bypassed and the requirement for this trace element is not known; nor has it been certain whether hypermanganesaemia causes the cholestasis or vice versa. We explored the direction of effect by serial tests of liver function after withdrawal of manganese supplements from children receiving long-term PN. We also examined the relation between blood manganese concentrations and brain lesions, as indicated by clinical examination and magnetic resonance imaging (MRI). METHODS: From a combined group of 57 children receiving PN we identified 11 with the combination of hypermanganesaemia and cholestasis; one also had a movement disorder. Manganese supplements were reduced in the first three and withdrawn in the remainder. MRI was done in two of these children. We also looked at manganese concentrations and MRI scans in six children who had received PN for more than 2 years without developing liver disease. FINDINGS: In the hypermanganesaemia/cholestasis group, four of the 11 patients died. In the seven survivors baseline whole-blood manganese was 615-1840 nmol/L, and after 4 months it had declined by a median of 643 nmol/L (p < 0.01). Over the same interval total bilirubin declined by a median of 70 mumol/L (p < 0.05). Two of these children had movement disorders, one of whom survived to have an MRI scan; this showed, with T1 weighted images, bilateral symmetrically increased signal intensity in the globus pallidus and subthalamic nuclei. Such changes were also seen in five other children--one from the hypermanganesaemia/cholestasis group and four of six in the long-term PN group without liver disease (in all of whom blood manganese was above normal). INTERPRETATION: The cholestasis complicating PN is multifactorial, but these results add to the evidence that manganese contributes. In view of the additional hazard of basal ganglia damage from high manganese levels in children receiving long-term PN, we recommend a low dose regimen of not more than 0.018 mumol/kg per 24 h together with regular examination of the nervous system.     

Peritoneal dialysis update 1994

Each year there are over 400 papers published in the field of peritoneal dialysis. In this review I have touched on only a few highlights of some of the more active areas of investigation and development. The advances in controlling peritonitis rates with the Y-set have been dramatic and have resulted in peritonitis rates in many centers less than one episode per 24 patient months. Technique survivals have also improved with lower peritonitis rates. The enormous literature on new approaches to treatment and new understandings of host defenses are beyond the scope of this review. There are also many advances in peritoneal access. We now have many new types of catheters under investigation such as the Swan-Neck Missouri catheter and the Moncrief-Popovich catheter, with complete burial of the catheter until eventual externalization for CAPD training. There have been major advances in understanding the normal healing of exit sites and the early diagnosis and treatment of exit-site infections. All the extensive literature on catheter development in the management of exit sites will be reviewed elsewhere. I have focused primarily on an update of worldwide demographics, some of the new findings in peritoneal transport, the use of low-calcium solutions, experiences with EPO, new thinking about adequacy and nutrition, and finally, on recent comparisons of CAPD and hemodialysis.     

Stability of the peritoneal membrane in long-term peritoneal dialysis patients

It is now well established that the formation of free radicals and oxidative stress-induced neuronal cell death can be involved in various neurodegenerative disorders, including Alzheimer's disease and Parkinson's disease. The pineal hormone melatonin has been suggested to be a neuroprotective antioxidant. To better understand the molecular mechanism of this activity, we compared the ability of melatonin and its precursor, N-acetyl-serotonin (normelatonin), to protect human neuroblastoma SK-N-MC cells and primary cerebellar granular neurons against oxidative stress. We found that normelatonin and melatonin have differential neuroprotective effects depending on the neuronal cell type. Normelatonin was more protective against hydrogen peroxide (H2O2) and glutamate-induced cell death in SK-N-MC cells compared to melatonin which was more effective to protect primary cerebellar granular neurons against the toxicity of H2O2, glutamate and N-methyl-D-aspartate when compared to normelatonin. At the molecular level, we tested the capacity of normelatonin and melatonin to inhibit the oxidative stress-induced NF-kappaB activation in both neuronal systems. Whereas normelatonin was more potent in the suppression of the activation of NF-kappaB by H2O2 in SK-N-MC cells compared to melatonin, no apparent differences in the extent of suppression could be detected in primary neurons. Normelatonin's and melatonin's neuroprotective activity in SK-N-MC neuroblastoma cells may be mediated by the suppression of NF-kappaB activation.     

Peritoneal dialysis in small laboratory animals

Healthy rats and guinea-pigs were treated with a simple method of continuous peritoneal dialysis for 12, 24 and 48 h. Increasing with time, both animal species developed severe hypoproteinemia and hemoconcentration due to protein loss into the dialyzate fluid. These changes were associated with a high mortality rate, when Sterofundin was used for dialysis. Therefore, protein loss should be substituted and the type of dialyzate must be considered in experimental long-term dialysis using these small laboratory animals.     

Peritoneal dialysis. Current status

Peritoneal dialysis has a definite role in the treatment of acute or chronic renal failure and certain fluid and electrolyte disturbances. Its major advantages are simplicity and availability. On the other hand, it is less effective and causes more patient discomfort than hemodialysis. Many factors enter into the decision to use one method of dialysis or the other, and the two should be considered complementary. The numerous complications that may occur during peritoneal dialysis can be avoided by careful attention to technical details. With the recent development of indwelling catheters and automatic cycling devices, long-term peritoneal dialysis is being used increasingly and successfully in the home, particularly in patients for whom home hemodialysis is difficult or inappropriate.     

Augmentation of nutritional intakes in children receiving long-term hemodialysis treatment

One of the major problems confronting children on long-term hemodialysis treatment is an inadequate intake of nutrients. The intake of calories, protein and minerals in children dialyzed for up to 3 years was documented in this study to be low. A simple method of augmenting the nutritional intake that has wide patient acceptibility is presented.     

Peritoneal dialysis in the prune belly syndrome

The article deals with the results of studies analyzing the fibrogenic activity and toxicity of asbestos-containing heat insulators exemplified by asbestos board, vulcanite and asbestos vermiculite. Physical and chemical parameters of the studied dust are presented. All studied dust types have the distinct fibrogenic activity, the highest one was seen in asbestos board. The studied dust types could be classified according to the acute toxicity: asbestos board (DL50-3.2 +/- 0.09 g/kg), chrysotile asbestos (DL50-2.0 +/- 0.08 g/kg), vulcanite (DL50-1.9 +/- 0.08 g/kg) and asbestos vermiculite (DL50-0.7 +/- 0.04 g/kg). The article touches upon the probable acting mechanism of acute toxicity of asbestos and asbestos-containing dust.     

Peritoneal solute transport predicts survival on CAPD independently of residual renal function

BACKGROUND: Loss of residual renal function has a profound effect on the survival of peritoneal dialysis patients. Less is known of the impact of peritoneal function. The purpose of this study was to investigate the influence of solute transport on clinical outcome in CAPD patients. METHODS: Two hundred and ten consecutive patients commencing CAPD since 1990 were enrolled into a single centre prospective longitudinal observational study of urea, protein, and peritoneal kinetics. On entry, and at 6-monthly intervals, estimations were made of weight, body mass index (BMI), plasma albumin, Kt/V, residual renal function (RRF), NPCR, low-molecular-weight solute transport (D/Pcreat), and peritoneal protein losses. All patients were censored in 1996, regardless of treatment modality. RESULTS: During the 6-year follow up period (median 22 months) there were 51 deaths, and the actuarial survival was 58% at 5 years. Urea, protein and peritoneal kinetics varied with time on dialysis: as anticipated there was a reduction in Kt/V, attributable to loss of RRF, whereas plasma albumin was stable for the first 2 years of treatment, but subsequently started to decline, a trend that became significant at 42 months. Peritoneal kinetics stabilized within the first 6 months of treatment and then showed a trend of increased solute transfer with time on treatment, which became significant by the end of the study. Comparing survivors with non-survivors Kt/V and RRF were similar at the start of treatment, but loss of RRF occurred significantly earlier in non-survivors than survivors (0.37 vs 0.68, P=0.02 at 6 months, 0.19 vs 0.54, P=0.01 at 12 months). D/Pcreat was also identical at commencement of treatment, but subsequently whilst survivors had stable solute transfer, non-survivors had consistently higher solute transfer beyond 6 months that reached increasing significance after 18 months, (0.70 vs 0.67, P=0.05 at 18 months, 0.72 vs 0.66, P=0.03 at 24 months). A Cox proportional hazard model constructed for the variables age, sex, BMI, albumin, Kt/V and D/Pcreat at 6 months of treatment indicated that low Kt/V (P=0.004), high D/Pcreat (P=0.013) and age (P=0.028) were independent predictors of death. CONCLUSION: There is good reason to believe that high peritoneal solute transport is an independent marker of poor outcome in CAPD patients.     

Peritoneal dialysis in treatment of diffuse purulent peritonitis]

Hypotensive efficacy and safety of local monotherapy with 0.005% xalathane (once a day) and combined therapy with 0.5% timolol (twice a day) and 2% pilocarpine (3 times a day) are compared in 24 patients with primary open-angle glaucoma. Mean decrease of intraocular pressure was significant in both groups. No side effects of xalathane were recorded. In one case there was a slight reddening of the eye and a sensation of discomfort Pilocarpine therapy was associated with miosis in all patients; half of them complained of obscure vision and headache after instillation. Monotherapy with xalathane is safe sufficiently effective, and comparable to combined therapy with timolol and pilocarpine.     

Peritoneal dialysis. An adjunct to pediatric postcardiotomy fluid management

The need for structural grafting in rhinoplasty arises when the nasal skeletal framework is weakened, malpositioned, or both. This review will be limited to structural grafting of the cartilaginous nasal skeleton. Current techniques will be reviewed and a technique introduced that addresses the common deformity of a superiorly rotated and deprojected nasal tip complex while simultaneously correcting nasal valve collapse. This technique is referred to as the Dynamic Adjustable Rotational Tip (DART) technique. The operative technique of the DART, as well as the basic philosophy regarding the tensile nature of the cartilaginous nasal skeleton will be described.