Melatonin prevents oxidative stress resulting from iron and erythropoietin administration

Intravenous iron (Fe) and recombinant human erythropoietin (rHuEPO) are routine treatments in the management of anemia in patients with chronic renal failure. We investigated the oxidative stress acutely induced by these therapies and whether pretreatment with oral melatonin (MEL) would have a beneficial effect. Nine patients (four women) were studied within 1 month of entering a chronic hemodialysis program in the interdialytic period. Plasma malondialdehyde (MDA), red blood cell glutathione (GSH), and catalase (CAT) activity were measured in blood samples obtained before (baseline) and 1, 3, and 24 hours after the administration of Fe (100 mg of Fe saccharate intravenously over 1 hour) or rHuEPO (4,000 U intravenously). One hour before these treatments, patients were administered a single oral dose of MEL (0.3 mg/kg) or placebo. Each patient was studied on four occasions, corresponding to studies performed using either placebo or MEL in association with intravenous Fe and rHuEPO administration. Baseline data showed increased oxidative stress in patients with end-stage renal failure. Increments in oxidative stress induced by Fe were more pronounced at the end of the administration: MDA, baseline, 0.74 +/- 0.09 nmol/mL; 1 hour, 1.50 +/- 0.28 nmol/mL (P: < 0.001); GSH, baseline, 2.51 +/- 0.34 nmol/mg of hemoglobin (Hb); 1 hour, 1.66 +/- 0.01 nmol/mg Hb (P: < 0.001); and CAT activity, baseline, 27.0 +/- 5.7 kappa/mg Hb; 1 hour, 23.3 +/- 4.2 kappa/mg Hb (P: < 0.001). rHuEPO-induced increments in oxidative stress were more pronounced (P: < 0.001) at 3 hours (MDA, 1.24 +/- 0.34 nmol/mL; GSH, 1.52 +/- 0.23 nmol/mg Hb; CAT activity, 18.0 +/- 3.1 kappa/mg Hb). MEL administration prevented the changes induced by Fe and rHuEPO and had no adverse side effects. These studies show that intravenous Fe and rHuEPO in doses commonly used to treat anemia in chronic hemodialysis patients acutely generate significant oxidative stress. Oral MEL prevents such oxidative stress and may be of clinical use.

Efficacy and safety of dipyrone versus tramadol in the management of pain after hysterectomy: a randomized, double-blind, multicenter study

BACKGROUND AND OBJECTIVES

We assessed the efficacy and safety of dipyrone in comparison with tramadol in the relief of early postoperative pain following abdominal hysterectomy.

METHODS

A total of 151 women between 18 and 60 years of age undergoing abdominal hysterectomy during general anesthesia participated in a randomized, double-blind, controlled, multicenter study. Seventy-three patients received dipyrone and 78 received tramadol. Patients received an intravenous loading dose of the study drug immediately after operation followed by intravenous (IV) maintenance infusion and IV on-demand boluses up to a maximum number of predetermined doses/day of 8 g dipyrone and 500 mg tramadol. The duration of the study was 24 hours.

RESULTS

The mean (SD) number of boluses in the dipyrone group was 3.8 (2.4) and 3.5 (2.5) in the tramadol group (95% confidence interval, -0.455 to 1.175), and the percentage of patients requiring rescue IV morphine (dipyrone 26.9%, tramadol 26.8%) was not statistically significant. Other analgesic efficacy parameters, such as pain intensity differences, sum of pain intensity differences, pain relief assessed by the patient, or patients who required the maximum number of demand doses, were not different between treatment groups. A significantly higher percentage of adverse gastrointestinal effects was found in patients given tramadol (42.1%) than in patients given dipyrone (20.2%) (P <.05). Also, a significantly higher number of tramadol-treated patients required ondansetron to control nausea and vomiting at 1 hour (19% v 7%), 2 hours (26% v 11%), and 24 hours (46% v 29%) (P <.05) after surgery. Patients and the investigators reported similar tolerability for both study arms.

CONCLUSIONS

Dipyrone and tramadol showed similar efficacy for early pain relief after abdominal hysterectomy. Nausea and vomiting, possibly caused by the tramadol, occurred more frequently in those patients. In this group, the need of the antiemetic drug ondansetron was also higher.

Tubular stress test detects subclinical reduction in renal functioning mass

BACKGROUND

To develop a test that would disclose subclinical impairment in renal function, we studied the increment in tubular secretion of creatinine (TS(Cr)) induced by intravenous creatinine administration.

METHODS

Studies were done in 14 normal individuals, 7 kidney donors (KDs), and 11 transplant recipients (Tx), all of whom had normal creatinine levels (P(Cr) <133 micromol/L). Creatinine infusion studies determined that maximal stimulation of TS(Cr) resulted from P(Cr) levels of 500 to 700 micromol/L. Therefore, in the tubular stress test, clearances, urinary excretion of creatinine (U(Cr)V) and TS(Cr) were determined before and after (15 to 105 min) a single bolus injection of 88.4 mmol/kg body wt, which resulted in the target P(Cr) levels.

RESULTS

Baseline determinations of P(Cr), U(Cr)V, and TS(Cr) were not significantly different in the study groups. Stimulated U(Cr)V (nmol/kg/min) was higher in normals (426 +/- 82) than in KDs (338 +/- 72, P < 0.05) and Tx patients (311 +/- 66, P < 0.01). Similarly, TS(Cr) (nmol/kg/min) was higher (P < 0.001) in normals (180 +/- 60) than in KDs (155 +/- 54) and Tx patients (86 +/- 35). Furthermore, the transplanted kidney responded worse than the solitary normal kidney (P < 0.05), despite having similar levels of glomerular filtration rate (GFR). The tubular stress test increased TS(Cr) 11.3 +/- 6.2 times in normals, 4.3 +/- 1.2 times in KDs (P < 0.01), and 2.5 times in Tx (P < 0.001).

CONCLUSIONS

Impaired tubular secretory response to a creatinine load is a more sensitive index of reduced functioning renal mass than levels of P(Cr) and GFR. The tubular stress test may be useful in following the natural history of kidney disease and the results of therapeutic interventions.

Endogenous hormone levels in habituated nucellar Citrus callus during the initial stages of regeneration

 Embryogenic nucellar callus cultures of different Citrus species and cultivars growing in hormone-free medium were transferred to medium containing either sucrose or glycerol as the only carbohydrate source. Glycerol has been reported to induce further development of Citrus somatic embryos, while in the presence of sucrose they continue to proliferate in an 'undifferentiated' manner. The endogenous hormone levels of the cultures were evaluated after 2 and 5  days to characterise the initial steps of embryo development. In most cases, differences among treatments were observed only after 5 days of culture. Higher cytokinin levels were found in most of the cultures transferred to the glycerol-containing medium. The effect of ageing sweet orange cultures on their endogenous hormone levels was determined by leaving them in the original culture medium without subculturing for 60 days. While no changes were observed in the free indoleacetic acid and gibberellin contents, lower levels of abscisic acid and cytokinins were found in the aged cultures than in those transferred at the normal interval, every 30 days. The endogenous hormone contents of Citrus callus of different genotypes were compared. Significant differences were observed in the levels of all hormones evaluated, even when the in vitro ontogeny of the different genotypes was very similar.

Tumor necrosis factor gene polymorphisms in patients with cirrhosis from chronic hepatitis C virus infection

Pro-inflammatory cytokines including tumour necrosis factor (TNF) mediate the pathogenesis of hepatitis C virus (HCV) infection. The distribution of TNF gene polymorphisms was examined among cirrhotic and non-cirrhotic patients infected with HCV. Thirty Caucasians with cirrhosis due to chronic HCV infection and 114 HCV-infected patients histopathologically free of cirrhosis were genotyped for genetic variants in TNF, lymphotoxin alpha and TNF-receptor type I using PCR-based techniques. Variability in the progression of HCV-related cirrhosis was assessed in a multivariate model including genetic and non-genetic factors such as gender, estimated duration of infection, alcohol consumption, and viral genotype. Viral genotype and non-genetic host features were not independently related to the occurrence or rate of development of cirrhosis in the patient population. In contrast, the TNF promoter variants TNF2 (-238A) and TNF3 (-308A) conferred a 3.2-fold and 5.1-fold risk of cirrhosis respectively (P = 0.03 for both). Reciprocal effects were observed with several TNF alleles and haplotypes defined by the -238G/A and -308G/A dimorphic sequences. Polymorphisms in the TNF alpha promoter appear to be associated with variability in the histological severity of chronic hepatitis C infection.

Assessment of hepatitis C virus RNA and genotype from 6807 patients with chronic hepatitis C in the United States

Hepatitis C virus (HCV) RNA status and HCV genotype have become important tools in the diagnosis and monitoring of therapy in chronic HCV infection. To establish a database with respect to HCV genotype and serum HCV RNA concentrations in chronic hepatitis C patients in the United States, we analysed 6807 chronic hepatitis C patients who had HCV RNA and HCV genotype tests conducted at a central laboratory. The HCV RNA concentration cut-off for the lower 25th percentile of this population (low titre) was 0.9 x 106 copies ml-1. The median HCV RNA concentration was 3.5 x 106 copies ml-1 and the cut-off for the upper 25th percentile (high titre) was 5 x 106 copies ml-1. Male patients had a median HCV RNA concentration of 3.9 x 106 copies ml-1, which was significantly higher than the median HCV RNA level for females (2.75 x 106 copies ml-1; P < 0.001). HCV genotype 1 was detected in 73% of patients; genotype 2 in 14%; genotype 3 in 8%; mixed genotype in 4%; and genotypes 4, 5 and 6 with a frequency of < 1%. Patients from the Northeast, Southeast and Midwest had significantly (P < 0.001) more infections with genotype 1 than patients from the Western and Southern regions. African-American patients were more likely to be infected with genotype 1 when compared with Caucasian, Hispanic or Asian Pacific Islanders (P < 0.001). Patients infected with HCV genotype 1 and mixed HCV genotypes had significantly higher serum HCV RNA concentrations when compared with HCV genotypes 2 and 3 (P < 0.001 for all comparisons).

Interleukin-1 polymorphisms associated with increased risk of gastric cancer

Helicobacter pylori infection is associated with a variety of clinical outcomes including gastric cancer and duodenal ulcer disease. The reasons for this variation are not clear, but the gastric physiological response is influenced by the severity and anatomical distribution of gastritis induced by H. pylori. Thus, individuals with gastritis predominantly localized to the antrum retain normal (or even high) acid secretion, whereas individuals with extensive corpus gastritis develop hypochlorhydria and gastric atrophy, which are presumptive precursors of gastric cancer. Here we report that interleukin-1 gene cluster polymorphisms suspected of enhancing production of interleukin-1-beta are associated with an increased risk of both hypochlorhydria induced by H. pylori and gastric cancer. Two of these polymorphism are in near-complete linkage disequilibrium and one is a TATA-box polymorphism that markedly affects DNA-protein interactions in vitro. The association with disease may be explained by the biological properties of interleukin-1-beta, which is an important pro-inflammatory cytokine and a powerful inhibitor of gastric acid secretion. Host genetic factors that affect interleukin-1-beta may determine why some individuals infected with H. pylori develop gastric cancer while others do not.

The responsiveness of the Hamilton Depression Rating Scale

In clinical studies of antidepressants, the Hamilton Depression Rating Scale (HAMD) total score has been the gold standard instrument for establishing and comparing the efficacy of new treatments. However, the HAMD is a multidimensional measure, which may reduce its ability to detect differences between treatments, in particular, changes in core symptoms of depression. Two meta-analyses were conducted to compare the responsiveness of the HAMD total score with several published unidimensional subscale scores based upon core symptoms of depression. The first compared the above instrument's ability to detect differences between fluoxetine and placebo across eight studies involving over 1600 patients. The second analysis involved four studies and over 1200 patients randomized to tricyclic antidepressants and placebo. In both meta-analyses, the unidimensional core subscales outperformed the HAMD total score at detecting treatment differences. The implications of this on sample sizes and power for clinical studies will be discussed. In fact, studies based on the observed effect sizes from the core subscales would require approximately one-third less patients than studies based on the HAMD total score. Effect sizes from each individual HAMD item will also be presented to help explain the differences in responsiveness between the scales.

Fecundity above the Species Level: Ovule Number and Brood Size in the Genisteae (Fabaceae: Papilionoideae)

Per-fruit components of fecundity (ovules per ovary, seeds per fruit, seed : ovule ratio, and patterns of seed maturation within pods) were studied in 33 species of the Genisteae, a legume tribe of mostly Mediterranean shrubs, e.g., Cytisus, Ulex, that also includes more widespread herbs such as Lupinus. Species identity explained most variance in both potential (ovules) and realized (seeds per fruit and seed : ovule ratio) fecundity, and although significant population-specific effects existed, these were relatively small, indicating that estimates of fecundity were not particularly prone to environment-induced changes. Average seed : ovule ratios varied between 20% (for a few species in which fixed rates of embryo abortion result into single seeded pods) and 100% (annuals), but most taxa were in the 40%-60% range. The probability that an ovule near the base of the ovary matured into a seed was significantly lower than the pod average in the majority of species. As indicated by the large size of stigmatic pollen loads, this was unlikely to result from insufficient pollination but rather from preferential embryo abortion. High abortion rates next to pod base occurred in both presumed selfers and obligate outcrossers. Evidence points to relatively stereotyped reproductive ways and high reproductive coherence in the tribe, with major departures from the norm being high seed : ovule ratios exhibited by annual Lupinus (associated with selfing), and low ratios shown by species with single seeded pods (associated with fixed rates of embryo abortion).

Microfungal Community Changes in Rodent Food Stores over Space and Time

> Abstract This paper reports the changes over time in the microfungal communities that inhabit three rodent species' food stores at two climatically different locations. Results reveal that microfungal diversity values calculated from above-ground food stores are highest in the more commonly disturbed portions of the rodent dens. Interactions among food-inhabiting microbes and between the rodents and food-inhabiting microbes also appear to influence the microfungal communities within the rodent dens. For example, our data suggest that transport by animal vectors, and not by air currents, is more effective at dispersing microbial propagules. Furthermore, although fungal communities inhabiting food stores within dens varied in composition and diversity over time, standardized substrates (sorghum seeds) simultaneously placed within the food stores converged in microfungal composition the longer they were left within the dens. We hypothesize that animal vectors, including rodents, make neighboring fungal communities more alike by introducing similar communities of microbes, which in turn initiate a cascade of biological interactions that, over time, result in similar microfungal communities inhabiting newly stored food items.http://link.springer-ny.com/link/service/journals/00248/bibs/38n1p79.html

Variation in volatile organic compounds in the breath of normal humans

We studied the variation in volatile organic compounds (VOCs) in the breath of 50 normal humans, using gas chromatography and mass spectroscopy. An average breath sample contained 204.2 VOCs (SD=19.8, range 157-241). The alveolar gradient of each VOC (abundance in breath minus abundance in air) varied with rate of synthesis minus rate of clearance. A total of 3481 different VOCs were observed: 1753 with positive alveolar gradients, 1728 with negative alveolar gradients. Twenty-seven VOCs were observed in all fifty subjects. This study confirmed previous reports of wide inter-individual variations. Two new findings were the comparatively small variation in total number of breath VOCs, and the presence of a 'common core' of breath VOCs in all subjects.

[Molecular diagnosis in an Argentinian family with multiple endocrine neoplasia type-1 (MEN-1)]

MEN-1 is a hereditary autosomal dominant syndrome characterized by the involvement of parathyroid glands, pancreatic islet cells and anterior pituitary gland. Today molecular genetics permit gene carrier analysis to compare the data obtained with the clinical biochemical tests. The twenty living members of the first, second and third generation of a family with MEN-1 were studied to determine the presence of genetic markers in MEN-1 loci 11q13, by linkage analysis and in affected individuals by biochemical tests and clinical examination. Two very informative polymorphic markers immediately flanking the MEN-1 gene on chromosome 11 band q13 were detected: PYGM and D11S987, haplotypes segregated by two members of the second generation, inherited from their father and two of the third generation: the affected one and one presymptomatic. The third generation had the affected member with renal stones and elevated PTH, PRL and glucagon. The presymptomatic carrier of MEN-1 allele showed elevated PTH. Among the members who inherited the normal allele we found one with elevated gastrin, one with elevated glucagon and one with elevated PTH, all asymptomatic. Of one Argentine family studied, molecular diagnosis allowed us to detect one presymptomatic carrier in the members at risk. As suggested by the available literature, accuracy of molecular diagnosis seems to make it the test of choice to exclude those members at risk for MEN-1 inheriting the normal allele.

Hormonal and psychological treatment: therapeutic alternative for menopausal women?

The purpose of this study was to determine whether psychological support associated with hormone replacement therapy (HRT) was more beneficial than replacement therapy alone. Our findings showed that HRT alone was more effective against vasomotor symptoms than HRT with psychological treatment (PT). While the combination of both treatment modalities (HRT + PT) was more effective against insomnia, nervousness, melancholy, fatigue, palpitations, and vertigo. Hormonal treatment alone and HRT with psychological treatment had little effect against paresthesia or tingling. Neither HRT alone nor HRT with psychological treatment was effective against joint and muscle pain or headache.

Clinical, cytogenetic, and molecular testing of Argentine patients with retinoblastoma

PURPOSE

The purpose of this study is to determine the clinical, chromosomal, and molecular characteristics of Argentine patients with unilateral and bilateral retinoblastoma.

STUDY DESIGN

Eighty-six patients belonging to 82 families were studied; 59% of them were examined during the first year of life. Leukocoria was the most common reason for consultation. Other presenting signs were strabismus and glaucoma. Enucleation of the affected eye was performed in 85% of the cases and the complication rate was 13%.

RESULTS

An appropriate therapy allowed the survival of 84 of the 86 patients. Two children with malformations and growth retardation had an abnormal karyotype with a deletion in 13q14. Segregation analysis of polymorphic sites within the retinoblastoma gene and the parental origin of the allele lost in the tumor were analyzed in 30 of the 82 families. Five mutant alleles transmitted through the germline and six de novo germline mutant alleles were identified in 12 patients with hereditary retinoblastoma. Most de novo germline mutant alleles were paternally derived. Molecular analysis of nonhereditary retinoblastoma showed loss of heterozygosity in three of eight cases. From these, two maternal alleles and one paternal allele were lost, thus not indicating a significant difference in the parental origin for the lost allele.

CONCLUSIONS

These data are useful for deoxyribonucleic acid diagnosis of susceptibility to retinoblastoma in relatives of hereditary patients, even if mutations have not been identified.

Stimulation of tubular secretion of creatinine in health and in conditions associated with reduced nephron mass. Evidence for a tubular functional reserve

BACKGROUND

The increment in glomerular filtration rate (GFR) after a protein load has been taken to reflect the renal reserve capacity; however, this response is preserved in end-stage kidney disease. Tubular secretion of creatinine is increased in relation to the GFR in renal failure, but little is known about the tubular functional response to stimulation despite the fact that tubulointerstitial lesions are always pre-eminent in chronic renal damage. Therefore we decided to compare the urinary creatinine excretion (UcrV) and tubular secretion of creatinine (TScr) induced by a test meat meal in normal individuals and in individuals with reduced nephron mass.

METHODS

We studied 12 normal subjects, seven healthy uninephrectomized (kidney donors) and eight patients with chronic renal disease (serum creatinine ranging from 212.2 to 486 micromol/l). They had been on a standard diet for 5 days before the studies. The test meal provided 80 g of animal protein. Three baseline and four stimulated (post-meal) 30-min simultaneous inulin and creatinine clearances were carried out.

RESULTS

We found that normals increased more than twice the UcrV (post-meal=329.5 +/-SEM 13.1 nmol/min/kg) and 3.4 times the TScr (114.4+/-12.7 nmol/min/kg) after the test meal. In contrast, patients were unable to raise their baseline values (P<0.001), despite a normal increment in GFR. The data in kidney donors fell between normals and patients. Strong correlation existed between the stimulated (but not the baseline) TScr (P=0.003) and GFR and between UcrV post-meal/pre-meal ratio and GFR (P<0.0001).

CONCLUSION

The increment in TScr resulting from a protein meal is related to the functioning nephron mass. Evaluation of this increment could have potential clinical relevance.