N-acetylcysteine reduces malondialdehyde levels in chronic hemodialysis patients--a pilot study

BACKGROUND

Oxidative stress has been implicated in the development of endothelial damage in hemodialysis (HD). We have assessed the effects of N-acetylcysteine (NAC), a compound with antioxidant effects, on malondialdehyde (MDA), a marker of oxidative stress on lipid peroxidation.

METHODS

A clinical trial was conducted in which 24 chronic HD patients were divided into 2 groups according to gender, age, time on HD and cause of renal failure. The NAC group (n = 12) received 600 mg of NAC twice a day for 30 days. The remaining patients constituted the control group (n = 12). MDA levels were measured pre- and post-dialysis at the beginning of the study (baseline) and on day 30 (30 days).

RESULTS

Baseline pre- and post-dialysis MDA levels were not different between both groups and were above normal values. A significant decrease was found in the NAC group when either pre- or post-dialysis MDA levels were compared to the corresponding control group levels on day 30 (pre-dialysis NAC vs control group 3.01 +/- 0.6 vs 4.5 +/- 0.73 micromol/l, p < 0.0001, post-dialysis NAC vs control group 2.76 +/- 0.5 vs 4.39 +/- 0.7 micromol/l, p < 0.0001). Only in the NAC group were pre-dialysis MDA 30-day levels different from pre-dialysis baseline levels (3.01 +/- 0.6 vs 5.07 +/- 1.6 micromol/l, p < 0.002). Post-dialysis MDA 30-day concentrations were significantly lower than post-dialysis MDA baseline levels (2.76 +/- 0.5 vs 4.32 +/- 0.7 micromol/l, p < 0.002) and pre-dialysis MDA 30-day measurements (2.76 +/- 0.5 vs 3.01 +/- 0.6 micromol/l, p < 0.011).

CONCLUSIONS

MDA levels are elevated in chronic HD patients and are not significantly reduced by HD. NAC significantly reduces malondialdehyde levels in chronic HD patients.

Sebastian syndrome: report of the first case in a South American family

The Sebastian syndrome (SS) is a MYH9-related disorders, which are an extremely infrequent group of four autosomal dominant illnesses. SS consist of giant platelets, leukocyte inclusions and thrombocytopenia. To our knowledge, there are no case reports of this syndrome in South America. The propositus was a 35-year-old Argentine woman with a history of purpuric lesions in her lower limbs and thrombocytopenia. Idiopathic thrombocytopenia purpura (ITP) was previously diagnosed, but she did not respond to treatment with steroids. Family history failed to provide any evidence of hearing loss, easy bruising, nephritis, renal failure or cataracts. The patient and 11 members of her family were evaluated. The diagnosis of SS was established by demonstrating giant platelets, thrombocytopenia and leukocyte inclusions in peripheral smear in two relatives and by peripheral smear and electronic microscopy in the propositus. MYH9-related disorders should be suspected whenever a patient has a low platelet count or a bleeding diathesis of unknown origin. In these cases, the history, carefully peripheral smear exam, immunocytochemistry and electronic microscopy will be of great help. Differentiation ITP with SS is important to avoid unnecessary diagnostic studies and treatments.

Chromium(VI) removal through facilitated transport using CYANEX 923 as carrier and reducing stripping with hydrazine sulfate

The transport of chromium(VI) through a flat-sheet supported liquid membrane (FSSLM) containing CYANEX 923 (mixture of phosphine oxides) as a carrier has been studied. The permeation of the metal is investigated as a function of various experimental variables: hydrodynamic conditions, concentration of chromium(VI) and HCI in the feed phase, CYANEX 923 concentration and diluent in the membrane, and strippant concentration in the receiving phase. By using hydrazine sulfate in the receiving phase, chromium(VI) is immediately reduced to the less toxic chromium(III). The aqueous mass transfer coefficient and the thickness of the aqueous boundary layer were calculated from the experimental results. The selectivity of CYANEX 923-based FSSLM toward different metal ions and the behavior of the system against other carriers is presented.

Nine novel mutations in maturity-onset diabetes of the young (MODY) candidate genes in 22 Spanish families

The aims of this study were to estimate the prevalence of major maturity-onset diabetes of the young (MODY) subtypes in Spanish MODY families and to analyze genotype-phenotype correlations. Twenty-two unrelated pediatric MODY patients and 97 relatives were screened for mutations in the coding region of the glucokinase (GCK), hepatic nuclear factor- HNF-1alpha and HNF4alpha genes using PCR-single strand conformation polymorphism and/or direct sequencing. In families carrying GCK mutations, the influence of genetic defects on fetal growth was investigated by comparing the birth weights of 32 offspring discordant for the mutations. Mutations in MODY genes were identified in 64% of the families. GCK/MODY2 mutations were the most frequently found, in 41%: seven novel (R369P, S411F, M298K, C252Y, Y108C, A188E, and S383L) and 2 already described mutations. Four pedigrees (18%) harbored mutations in the HNF-1alpha/MODY3 gene, including a previously unreported change (R271G). One family (4%) carried a novel mutation in the HNF-4alpha gene (IVS5-2delA), representing the first report of a MODY1 pedigree in the Spanish population. The age at diagnosis was prepubertal in MODY2 index patients and pubertal in MODY3 patients. Overt diabetes was rare in MODY2 and was invariably present in MODY3 index patients. Chronic complications of diabetes were absent in the MODY2 population and were present in more than 40% of all relatives of MODY3. Birth weight was lower in the presence of a GCK fetal mutation when the mutation was of paternal origin. The MODY1 patient was diagnosed at 15 yr of age. She developed intermittent microalbuminuria despite good metabolic control, and severe late-onset complications were common within her family. Mutations in the GCK/MODY2 gene are the most common cause of MODY in our population as recruited from pediatric and adolescent index patients. The inheritance of GCK defects by the fetus results in a reduction of birth weight. Clinical expression of MODY3 and MODY1 mutations, the second and third groups of defects found, was more severe, including the frequent development of chronic complications.

Direct coronary stenting versus stenting with balloon pre-dilation: immediate and follow-up results of a multicentre, prospective, randomized study. The DISCO trial. DIrect Stenting of COronary Arteries

AIMS

To assess the safety of direct coronary stenting, its influence on costs, duration of the procedure, radiation exposure, clinical outcome and angiographic restenosis.

METHODS AND RESULTS

We randomized 416 patients (446 lesions) to direct stent implant or stent implant following balloon pre-dilation. Patients >75 years old, heavily calcified lesions, bifurcations, total occlusions, left main lesions and very tortuous vessels were excluded. Direct stenting was successful in 217/224 lesions (96.8%). No single loss or embolization of the stent occurred. All stents in the group with pre-dilation were effectively deployed. The immediate post-procedure angiographic results were similar with both techniques. Fluoroscopy and procedural time were significantly lower in direct stenting (6.4+/-0.3 and 21+/-0.9 min) than in pre-dilated stenting (9.1+/-0.4 and 27.5+/-1.1 min) (P>0.001). Major adverse cardiac events during hospitalization were one in direct and four in pre-dilated stenting (P=0.05) but there were no significant differences at follow-ups at 1, 6 and 12 months between the two groups. Angiographic reevaluation at 6 months was performed in 94% of the cases. Restenosis rate was 16.5% in direct stenting and 14.3% in pre-dilated stenting (P=ns).

CONCLUSIONS

Direct stenting is as safe as pre-dilated stenting in selected coronary lesions. Acute angiographic results are similar but procedural costs, duration of the procedure and radiation exposure are lower in direct stenting. Overall success rate, mid-term clinical outcome and restenosis are similar with both techniques.

Biochemical responses of Pinus pinaster trees to fire-induced trunk girdling and crown scorch: secondary metabolites and pigments as needle chemical indicators

The biochemical responses to varying levels of localized heat damage to stems and crowns were studied in Pinus pinaster trees in Galicia, Spain. The objective was to ascertain the utility of secondary metabolites (total polyphenols. condensed tannins, astringency, free and esterified phenolic acids) and pigments (chlorophylls and carotenoids) as chemical indicators of localized fire damage. The study involved three levels of girdling by trunk heating (0%, 60%, and 75%), three levels of crown scorching (0%, 50%, and 75%), and all combinations of those trunk and crown treatment levels. Secondary metabolites and pigments were analyzed in needles before, during, and up to 8 months after fire treatments. High levels of polyphenols, condensed tannin, and pigments occurred in situations where the sole treatment was 75% crown scorching. Low levels of hydroxycinnamic acids were the result when the treatment was 75% trunk girdling. These responses occurred in the first two months after fire. Thereafter, normal values were observed. Low values of chlorophyll a/b ratio and high levels of free protocatechuic and esterified syringic acids were found to be long-term indicators of trunk girdling damage combined with crown scorching.

Monte Carlo estimation of absorbed dose to organs in computed tomography

This paper proposes a method to estimate absorbed doses to organs in explorations using computed tomography. This Monte Carlo-based method is a generalization of a previous method applied to conventional diagnostic radiology and is also applicable to radiotherapy techniques using photons or electrons. This study is applied to the estimation of absorbed doses to different parts of the head in a simple head CT examination. Simulation was performed for different arrangements (monoenergetic beam, spectrum, different number of histories, etc.). Comparison of the results with experimental doses measured in a human phantom by thermoluminescent dosimeters indicates that the method is capable of adequately estimating doses to organs in computed tomography.

Treatment with the insulin analogue lispro in children and adolescents with type 1 diabetes mellitus: evaluation over a 3-year period

The aim of the present study was to evaluate the degree of metabolic control obtained with the use of the insulin analogue lispro compared to the previous regimen with classical regular insulin in children and adolescents with Type 1 diabetes mellitus. HbA1c, lipid metabolism, body mass index (BMI), frequency of severe hypoglycaemia, carbohydrate intake, total daily insulin requirements and its distribution during the day were analysed in 44 diabetics patients (57% males and 43% females) throughout a 3-yr period. The mean age of the patients at the beginning of the study was 15.6 +/- 2.7 yr with a mean duration of the disease of 8.01 +/- 3.4 yr. All data were evaluated for the year before the change of treatment, and 1 yr (44 patients), 2 yr (19 patients) and 3 yr (13 patients) after the change. HbA1c levels did not significantly change (6.6 +/- 1.1% with regular insulin, 6.32 +/- 1.05% in the 1st year with lispro, 6.6 +/- 1.1% in the 2nd yr with lispro, 6.33 +/- 0.9% in the 3rd yr with lispro). However, significant differences (p = 0.03) were found after 3 yr of treatment in those patients who changed to insulin lispro therapy due to a bad glycaemic control. The total daily insulin dose (U/kg/d) remained unchanged. The total short-acting/intermediate-acting insulin ratio significantly decreased (45.9 +/- 0.1% regular insulin; 37.2 +/- 0.1% 1st yr lispro (p < 0.001); 33.6 +/- 0.1% 2nd yr lispro (p < 0.05); 35.5 +/- 0.1% 3rd yr lispro (p < 0.05). BMI and lipid profile remained unchanged. The self-reported daily carbohydrate in take significantly decreased due to a reduction of snacks. Total number of episodes of severe hypoglycaemia did not change significantly. In conclusion insulin lispro treatment did not modify the daily insulin dose, but reduced the short-acting/intermediate acting insulin ratio. The metabolic control remained unchanged. The number of patients reporting severe hypoglycaemia was similar despite the treatment schedule. After this 3-yr duration trial all patients decided to continue the treatment with lispro insulin.

Interaction of alpha-2-macroglobulin and HSV-1 during infection of neuronal cells

We describe the effect of pretreatment with alpha-2-macroglobulin (A2M) on the susceptibility of the human neuroblastoma SKNMC cell line to infection by herpes virus type 1 (HSV-1). ELISA and co-immunoprecipitation experiments confirmed the A2M-HSV-1 interaction in vitro. Indirect immunofluorescence shows that A2M exacerbated the cytopathic effect induced after HSV-1 infection. However, A2M-pretreated SKNMC cells notably produced fewer HSV-1 particles than did the untreated cells, suggesting that A2M could induce a restrictive infection. Furthermore, high levels of HSV-1 and A2M induced the production of nitric oxide (NO) in SKNMC. Preliminary results suggest that A2M might induce apoptosis in HSV-1-infected cells. These findings affirm the conclusion that A2M may interact directly with HSV-1 and modulate the course of the infection in SKNMC human neuroblastoma cells.

The ubiquitin-proteasome cascade is required for mammalian long-term memory formation

It has been recently demonstrated that ubiquitin-proteasome-mediated proteolysis is required for long-term synaptic facilitation in Aplysia. Here we show that the hippocampal blockade of this proteolytic pathway is also required for the formation of long-term memory in the rat. Bilateral infusion of lactacystin, a specific proteasome inhibitor, to the CA1 region caused full retrograde amnesia for a one-trial inhibitory avoidance learning when given 1, 4 or 7h, but not 10 h, after training. Proteasome inhibitor I produced similar effects. In addition, inhibitory avoidance training resulted in an increased ubiquitination and 26S proteasome proteolytic activity and a decrease in the levels of IkappaB, a substrate of the ubiquitin-proteasome cascade, in hippocampus 4 h after training. Together, these findings indicate that the ubiquitin-proteasome cascade is crucial for the establishment of LTM in the behaving animal.

Prevalence of infectious diseases among internationally adopted children

OBJECTIVE

Internationally adopted children are at increased risk of infections acquired in their country of origin. Ongoing surveillance of this unique population is needed to detect changing epidemiology and provide appropriate care.

METHODS

We performed a retrospective cohort study of 504 children adopted from abroad and evaluated from 1997 to 1998 to determine the prevalence of and factors associated with various infectious diseases.

RESULTS

The mean age of the study participants at medical evaluation was 1.6 years; 71% were girls, and they were adopted from 16 countries, including China (48%), Russia (31%), Southeast Asia (8%), Eastern Europe (8%), and Latin America (5%). Overall, 75 (19%) of 404 children tested had tuberculin skin tests >/=10 mm, but all had normal chest radiographs. BCG vaccination (odds ratio [OR]: 7.37; 95% confidence interval [CI]: 3.29, 17.16) and being Russian born (OR: 2.90; 95% CI: 1.68, 5.00) were risk factors for latent tuberculosis infection. Fourteen (2.8%) children had detectable hepatitis B surface antigen, but no child had active hepatitis C, human immunodeficiency virus, or syphilis. Giardia lamblia antigen was detected in 87 (19%) of 461 tested children, and such children were older (mean: 22 months vs 15.5 months) and more likely to have been born in Eastern Europe (OR: 2.82; 95% CI: 1.70, 4.68).

CONCLUSIONS

We demonstrated increased rates of latent tuberculosis infection and G lamblia infection than previously reported. Thus, ongoing surveillance of internationally adopted children, international trends in infectious diseases, and appropriate screening will ensure the long-term health of adopted children as well as their families.

Raman spectroscopy of secondary structure of elastinlike polymer poly(GVGVP)

Raman spectra of the elastinlike polypentapeptide poly(GVGVP) were measured in H(2)O and D(2)O as solutions and, after increasing the temperature, as suspensions and sediments. In addition, spectra of the polypentapeptide in the solutions of increasing concentration and in the solid state were also investigated by gradually evaporating the water. Significant changes in band frequencies, intensities, and shapes were found for selected Raman bands in the measured spectra, particularly for the C-H stretching, the glycine CH(2) wagging, and some amide vibrations. The C-H stretching vibrations are influenced predominantly by the presence of water, the glycine CH(2) wagging vibrations are associated with conformational transitions. Three possible types of poly(GVGVP)s in the presence of water were indicated: polymer chains in a relatively extended state in the solution, a beta-spiral structure in the suspension, and irregularly bent chains in the sediment.

[Costs of chronic dialysis in a public hospital: myths and realities]

In this study regular dialysis treatment costs during 1998 and 1999 in a public hospital, which is responsible for a population of 178,000, has been analysed. Hemodialysis (HD) and peritoneal dialysis (PD) costs have been differentiated and compared with those of external providers. The best technical and productive efficiency of both treatments have been estimated by analyzing the "treatment cost/human resources of the community utilized" relationship. The HD treatment costs per patient per year were 20,343 and 18,871 euros in 1988 and 1,999, respectively, lower than the costs reported in other studies. In 1999 these costs were similar to those of external providers and lower than the PD treatment costs (23,295 euros). HD retains its advantage even after costs of erythropoietin, hospital admissions and transport are included. In the hospital studied, the best technical efficiency in HD would be reached with 64 patients on treatment (17,851 euros per patient per year) and in PD with 48 patients (21,167 euros per patient per year). If we take into account our population characteristics and consider a patient distribution of 70% on HD and 30% on PD, the best productive efficiency would be reached with 56 patients on HD (17,916 euros per patient per year) and 24 patients on PD (21,813 euros per patient per year). HD confers the greatest economic and social benefits on the population supplied by the hospital since it provides the community with more jobs than PD in relation to treatment costs while the two yield the same clinical results. In conclusion, HD in a public hospital, at least in our environment, may be efficient and competitive with HD from external providers and it may be more efficient and provide a bigger economic and social profit for the population serviced by the hospital than PD, at least while the current supply systems for this treatment in our country are maintained.