Implication of biofilm formation in the persistence of urinary tract infection caused by uropathogenic Escherichia coli

Escherichia coli is the most frequent microorganism involved in urinary tract infection (UTI). Acute UTI caused by uropathogenic E. coli (UPEC) can lead to recurrent infection, which can be defined as either re-infection or relapse. E. coli strains causing relapse (n = 27) and re-infection (n = 53) were analysed. In-vitro production of biofilm, yersiniabactin and aerobactin was significantly more frequent among strains causing relapse. Biofilm assays may be helpful in selecting patients who require a therapeutic approach to eradicate persistent biofilm-forming E. coli strains and prevent subsequent relapses.

Genetics of Obesity: Gene × Nutrient Interactions

Obesity results from a long-term positive energy balance, in which gene-related differences may account for some of the disparities found in weight gain among populations. However, the rising prevalence of obesity in developed and developing societies must reflect lifestyle changes. Despite that the genetic background remains stable over many generations, obesity may be derived from a failure on the homeostasis systems, as a consequence of a dysfunction at the genetic level, which may be affected by changing environmental exposure (dietary habits, sedentarism, etc). In practice, obesity risk at least depends on two important factors, which mutually interact: 1) genetic variants and gene expression changes in candidate genes and 2) exposure to environmental risk factors. Disagreements among studies involving gene-nutrient interactions may reflect the difficulty of accurate measurement of specific types of dietary macro and micronutrients intake as well of phenotype assessment rather than a discrepancy in biological relevance. Identification of individuals who are genetically more likely to respond to particular dietary changes may be important for successful intervention in obesity treatment, since gene screening will allow health professionals to tailor-design weight management and dietary guidance in individuals with a genetic predisposition to become obese.

Rescue and regeneration of injured peripheral nerve axons by intrathecal insulin

Insulin peptide, acting through tyrosine kinase receptor pathways, contributes to nerve development or repair. In this work, we examined the direction, impact and repertoire of insulin signaling in vivo during peripheral nerve regeneration in rats. First, we demonstrated that insulin receptor is expressed on lumbar dorsal root ganglia neuronal perikarya using immunohistochemistry. Immunoblots and polymerase chain reactions confirmed the presence of both alpha and beta insulin receptor subunits in dorsal root ganglia. In vivo and in vitro assessment of dorsal root ganglion neurons showed preferential localization of insulin receptor to perikaryal sites. In vivo, intrathecal delivery of fluorescein isothiocyanate-labeled insulin identified localization around dorsal root ganglia neurons. The direction and impact of potential insulin signaling was evaluated by concurrently delivering insulin or carrier over a 2 week period using mini-osmotic pumps, either intrathecally, near nerve, or with both deliveries, following a selective sural nerve crush injury. Only intrathecal insulin increased the number and maturity of regenerating sensory sural nerve axons distal to the crush site. As well, only intrathecal insulin rescued retrograde loss of sural axons after crush. In a separate experiment, insulin also rescued retrograde loss and atrophy of deep peroneal, largely motor, axons post-injury. Intrathecal insulin increased the expression of calcitonin-gene-related peptide in regenerating sprouts, increased the number of visualized regenerating fiber clusters, and reduced downregulation of calcitonin-gene-related peptide in dorsal root ganglia neurons. Insulin delivered intrathecally does not appear to influence expression of insulin-like growth factor-1 at dorsal root ganglion neurons or near peripheral nerve injury, but was associated with upregulation of insulin receptor alpha subunit in dorsal root ganglia. Intrathecal insulin delivery was associated with greater recovery of thermal sensation and longer distances to stimulus response with the pinch test following sural nerve crush. Insulin signaling at neuron perikarya can drive distal sensory axon regrowth, rescue retrograde alterations of axons and alter axon peptide expression. Moreover, such actions are associated with upregulation of its own receptor.

Olive oil consumption and weight change: The SUN prospective cohort study

The aim of this dynamic prospective follow-up study was to assess the association between olive oil consumption and the likelihood of weight gain or the incidence of overweight or obesity in a large Mediterranean cohort of 7,368 male and female Spanish university graduates (the SUN Project) who were followed for a median period of 28.5 mon. A validated Food Frequency Questionnaire was administered at baseline, and respondents also completed a follow-up questionnaire after 28.5 mon. Changes in participants' consumption of olive oil and their weight were assessed during follow-up. A higher baseline consumption of olive oil was associated with a lower likelihood of weight gain, although the differences were not statistically significant. The adjusted difference in weight gain (kg) was -0.16 [95% confidence interval (CI): -0.42 to +0.11] for participants in the upper quintile of olive oil consumption (median: 46 g/d) compared with those in the lowest quintile (median: 6 g/d). For participants with a high baseline consumption of olive oil whose olive oil consumption also increased during follow-up, we found a slightly increased but nonsignificant risk of incidence of overweight or obesity (adjusted odds ratio = 1.19, 95% CI: 0.73 to 1.95). Our study, carried out in a sample of free-living people, shows that a high amount of olive oil consumption is not associated with higher weight gain or a significantly higher risk of developing overweight or obesity in the context of the Mediterranean food pattern.

High-fat feeding period affects gene expression in rat white adipose tissue

The expression of 76 sequences, previously isolated as differentially expressed in visceral white adipose tissue (WAT) of female rats, fed with a high-fat diet for 11 days (Lopez et al., Biochem Biophys Res Comm 318: 234-239, 2004), was analyzed in epidydimal WAT of male rats after a feeding period of 65 days with the same diet, using microarray technology. After Northern blot validation of the results, only three genes appeared upregulated (caveolin-2, the alpha-1 chain of haemoglobin and rat mammary tumor-7) and two downregulated (adiponectin and dystroglycan). We have also analyzed caveolin-1 gene expression and found that follows the opposite pattern of caveolin-2, indicating that they are inversely regulated. Our results suggest that if feeding with a high-fat diet is prolonged, many of the initial changes in gene expression, probably aimed to consume the energy surplus and prevent excessive fat deposition, are not maintained, and adaptation to an increased lipid storage is developed.

Randomized, multi-center trial of two hypo-energetic diets in obese subjects: high- versus low-fat content

OBJECTIVE

To investigate whether a hypo-energetic low-fat diet is superior to a hypo-energetic high-fat diet for the treatment of obesity.

DESIGN

Open-label, 10-week dietary intervention comparing two hypo-energetic (-600 kcal/day) diets with a fat energy percent of 20-25 or 40-45.

SUBJECTS

Obese (BMI >or=30 kg/m(2)) adult subjects (n = 771), from eight European centers.

MEASUREMENTS

Body weight loss, dropout rates, proportion of subjects who lost more than 10% of initial body weight, blood lipid profile, insulin and glucose.

RESULTS

The dietary fat energy percent was 25% in the low-fat group and 40% in the high-fat group (mean difference: 16 (95% confidence interval (CI) 15-17)%). Average weight loss was 6.9 kg in the low-fat group and 6.6 kg in the high-fat group (mean difference: 0.3 (95% CI -0.2 to 0.8) kg). Dropout was 13.6% (n = 53) in the low-fat group and 18.3% (n = 70) in the high-fat group (P=0.001). Among completers, more subjects lost >10% in the low-fat group than in the high-fat group ((20.8%, n = 70) versus (14.7%, n = 46), P = 0.02). Fasting plasma total, low-density lipoprotein- and high-density lipoprotein-cholesterol decreased in both groups, but more so in the low-fat group than in the high-fat group. Fasting plasma insulin and glucose were lowered equally by both diets.

CONCLUSIONS

The low-fat diet produced similar mean weight loss as the high-fat diet, but resulted in more subjects losing >10% of initial body weight and fewer dropouts. Both diets produced favorable changes in fasting blood lipids, insulin and glucose.

Clinical characterization of breakthrough bacteraemia: a survey of 392 episodes

BACKGROUND

Few data are available on the clinical features of patients who develop breakthrough bacteraemia, understood as positive blood cultures despite appropriate antibiotic therapy.

OBJECTIVES

To determine the clinical significance and outcome of a large series of breakthrough bacteraemia.

DESIGN

Retrospective analysis of a prospectively collected database.

SETTING

Two university-affiliated hospitals in Catalonia, Spain.

SUBJECTS

A total of 392 individuals who suffered an episode of breakthrough bacteraemia recorded between 1997 and 2002.

INTERVENTIONS

Demographic characteristics, underlying diseases, origin of infection, sources of infection, microorganisms isolated, McCabe and Jackson prognostic criteria, and mortality were analysed.

RESULTS

Breakthrough bacteraemia was detected in 392 of 6324 (6.1%) episodes of bacteraemia. Eighty per cent of episodes were nosocomial. The most frequent source of infection in breakthrough bacteraemia was endovascular (70%). Coagulase-negative staphylococci, Staphylococcus aureus, and Pseudomonas aeruginosa were the most significant microorganisms involved. Nosocomial acquisition together with selected sources (central venous catheter, endocarditis and other endovascular foci), underlying conditions (neutropenia, polytraumatism, allogenic bone marrow and kidney transplantation), and particular microbial aetiologies (S. aureus, P. aeruginosa and polymicrobial) were independently associated with increased risk for developing breakthrough bacteraemia. Crude mortality rate was greater in patients with breakthrough bacteraemia (16% vs. 12.3%; P<0.05), and this condition was an independent predictor of death (OR 1.4, 95% CI, 1-1.9; P=0.04).

CONCLUSIONS

In view of a case of breakthrough bacteraemia it is mandatory to search for an endovascular focus. Empiric treatment should be directed to cover S. aureus, coagulase-negative staphylococci and nonfermentative Gram-negative bacilli. Breakthrough bacteraemia is an independent predictor of death.

An integrated system to remote monitor and control anaerobic wastewater treatment plants through the internet

The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem.

Modular expert system for the diagnosis of operating conditions of industrial anaerobic digestion plants

Anaerobic digestion (AD) plants are highly efficient wastewater treatment processes with possible energetic valorisation. Despite these advantages, many industries are still reluctant to use them because of their instability in the face of changes in operating conditions. To the face this drawback and to enhance the industrial use of anaerobic digestion, one solution is to develop and to implement knowledge base (KB) systems that are able to detect and to assess in real-time the quality of operating conditions of the processes. Case-based techniques and heuristic approaches have been already tested and validated on AD processes but two major properties were lacking: modularity of the system (the knowledge base system should be easily tuned on a new process and should still work if one or more sensors are added or removed) and uncertainty management (the assessment of the KB system should remain relevant even in the case of too poor or conflicting information sources). This paper addresses these two points and presents a modular KB system where an uncertain reasoning formalism is used to combine partial and complementary fuzzy diagnosis modules. Demonstration of the interest of the approach is provided from real-life experiments performed on an industrial 2,000 m3 CSTR anaerobic digester.

NF-kappa B-binding activity in an animal diet-induced overweightness model and the impact of subsequent energy restriction

An impaired immune function linked to obesity has been shown in both human and animal studies. The purpose of this work was to analyse the hypothesis that PPAR gamma 1 participates in the inhibition of the immune response by affecting the DNA-binding ability of the NF-kappa B complex and whether the SREBP-1 expression can regulate PPAR gamma 1 expression in spleen. Diet-induced overweight rats showed higher PPAR gamma 1 (p<0.05) and lower SREBP-1 (p<0.01) mRNA expression levels with an inhibition of the DNA-binding ability of NF-kappa B compared to control rats as determined by gel-shift analysis. On the other hand, energy restriction decreased SREBP-1 (p<0.01) mRNA expression with no differences in PPAR gamma 1 mRNA expression compared to non-restricted rats, which was accompanied by a restoration in the DNA-binding ability of NF-kappa B as shown by gel-shift analysis. These results suggest that PPAR gamma 1 may be involved in the altered immune response through changes in the activity of NF-kappa B.

Monocyte function in healthy middle-aged people receiving fermented milk containing Lactobacillus casei

BACKGROUND

Lactic acid bacteria have been suggested as a dietary strategy to enhance immune system activity.

OBJECTIVE

The aim of the current work was to test the effects of a Lactobacillus casei fermented milk consumption on monocyte activity of middle-aged volunteers.

DESIGN

Forty-five healthy volunteers, 24 women and 21 men (aged: 51 - 58 years), were randomized in two groups to receive three cups per day of a fermented milk containing L. casei DN114001 (108 - 1010/g) (n = 23), or placebo (n = 22), during 8 weeks. White blood cell count and the oxidative burst capacity of monocytes and granulocytes were examined with a FACScalibur. Measurements were performed at baseline and after the nutritional intervention, at day fifty-six.

RESULTS

After the trial, no changes in immune cell proportions were detected in both groups, as well as in monocyte activity after the placebo consumption (p = 0.625). However, volunteers included in the probiotic-treated group increased (p = 0.029) their oxidative burst capacity of monocytes, and this increment inversely and significantly correlated with the intensity registered at baseline (r = -0.653, p = 0.004).

CONCLUSIONS

Results showed that daily intake of fermented milk containing Lactobacillus casei was able to module the oxidative burst capacity of monocyte subset in healthy middle-aged people, particularly in subjects with lower initial levels. Thus, this nutritional strategy could be considered to maintain immune competence in ageing.

Basal fat oxidation and after a peak oxygen consumption test in obese women with a beta2 adrenoceptor gene polymorphism

The Glu27Glu genotype in the beta2-adrenergic receptor (ADRB2) has been linked to a higher fat deposition and obesity in females. Also, in our population, it has been described that physically active women carrying the Glu allele had a higher BMI as compared to non-carriers performing the same level of activity. Since exercise may counterbalance a gene predisposition to obesity, we tested the hypothesis of a potential different metabolic response among ADRB2 Gln27Gln versus Glu27Glu obese women when submitted to a peak oxygen consumption test on a treadmill. In our study, 10 obese women with the Gln27Gln genotype were compared to 9 matched obese women bearing the Glu27Glu genotype. The ADRB2 polymorphism was identified by PCR-RFLP, fat oxidation was determined by indirect calorimetry and blood measurements were carried out following conventional procedures. The ADRB2 Glu27Glu subjects had lower plasma glycerol levels (P = 0.026), while plasma triglycerides (P <0.001) and the insulin:glucose ratio were higher (P = 0.046) as compared to the Gln27Gln group along the peak oxygen consumption trial intervention. There was a significantly lower fat oxidation (P = 0.024) in the Glu27Glu obese women during the recovery compared to Gln27Gln obese individuals. These data suggest that exercise would not benefit equally the two ADRB2 polymorphism homozygous groups, since both lipolysis and fat oxidation promoted by a peak oxygen consumption test appear to be blunted in the polymorphic Glu27Glu obese group.

A novel nonsense mutation in the melanocortin-4 receptor associated with obesity in a Spanish population

BACKGROUND

In recent years, several groups have reported dominant inheritance of obesity conferred by missense, nonsense and frameshift mutations in the melanocortin 4 receptor gene (MC4R). Hence, MC4R is involved in the most common monogenic form of human obesity described so far.

OBJECTIVES

In this context, we screened a Spanish population, composed of obese subjects and normal weight controls, for mutations in the MC4-R by single-strand conformational polymorphism (SSCP).

SUBJECTS AND METHODS

Overall 313 individuals, 159 obese subjects (body mass index: BMI: 37.6 kg/m(2), 95% CI: 36.7-38.5 kg/m(2)) and 154 normal weight control subjects (BMI: 22.3 kg/m(2), 95% CI: 22.0-22.6 kg/m(2)) were screened for MC4-R mutations.

RESULTS

We detected a novel nonsense mutation at codon 16 of the MC4-R in an obese female (BMI: 30.0 kg/m(2)) and a previously described missense mutation (Val-253-Ile) located within the sixth trans-membrane domain of the MC4-R in a normal weight individual (BMI: 19.0 kg/m(2)). The polymorphism Val-103-Ile was detected in one obese individual, while four subjects (two cases and two controls) with the polymorphism Ile-251-Leu were found.

CONCLUSIONS

We have identified a novel nonsense mutation (Trp-16-Stop) that, based on previously described frameshift and nonsense mutations, most likely results in dominantly inherited obesity. Within this Spanish population, the frequency of the Ile-251-Leu polymorphism of the MC4R was similar in obese and control subjects (about 1.3%), while the polymorphism Val-103-Ile was only detected in an obese individual (0.6%).

TRP64ARG polymorphism of the beta 3-adrenergic receptor gene and obesity risk: effect modification by a sedentary lifestyle

AIM

We performed a case-control study to assess the association between obesity risk and the Trp64Arg polymorphism of the beta 3-adrenergic receptor gene.

METHODS

Obese subjects [n = 159; body mass index (BMI) > 30 kg/m2] and controls (n = 154; BMI < 25 kg/m2) were compared using multivariable logistic regression to control for potential confounders.

RESULTS

A higher obesity risk (adjusted OR: 2.98; 95% CI: 1.00-8.56; p = 0.05) was associated with the Trp64Arg polymorphism among sedentary, but not among more active people.

CONCLUSIONS

Our results suggest that the TRP64ARG polymorphism of the ADRB3 seems to be a risk factor for obesity that is dependent on a sedentary lifestyle.

Gln27Glu polymorphism in the beta2 adrenergic receptor gene and lipid metabolism during exercise in obese women

BACKGROUND

The Glu27Glu genotype in the beta-2-adrenergic receptor (ADRB2) is associated with fat mass, body mass index and obesity in females. In our population, we previously found an association of higher body mass index (BMI) among women who reported more physical activity and carried the Glu27 allele as compared to non carriers with the same level of activity.

OBJECTIVE

To examine the lipid metabolism differences, both at rest and during submaximal exercise in ADRB2 Glu27Glu vs Gln27Gln obese women.

SUBJECTS

Eight obese women with the Glu27Glu genotype (age, 43+/-5 y; body mass index (BMI), 31.7+/-0.9 kg/m(2); percentage fat mass, 42.0+/-1.3; WHR, 0.83+/-0.02; and VO(2max), 21.6+/-0.9 ml/kg/min) were compared with seven obese women with the Gln27Gln genotype (age, 43+/-5 y; BMI, 33.9+/-1.3 kg/m(2); percentage fat mass, 41.6+/-1.2; WHR, 0.83+/-0.02; and VO(2max), 20.6+/-0.8 ml/kg/min).

MEASUREMENTS

The ADRB2 polymorphism was identified by PCR-RFLP. Respiratory quotient was determined by indirect calorimetry at baseline, during 1 h of walking on a treadmill and 1 h after the exercise. Plasma triglycerides, glycerol, FFA, hydroxybutyrate, glucose and lactate were assayed by spectrophotometric methods. Insulin, leptin and progesterone were measured by radioimmunoassay. Adrenaline and noradrenaline were quantified by high performance liquid chromatography.

RESULTS

The ADRB2 Glu27Glu subjects had lower plasma glycerol (P=0.047) and lower hydroxybutyrate (P=0.001) throughout the study than the Gln27Gln group. Plasma triglycerides (P=0.001), lactate (P<0.05) and serum insulin (P<0.05) remained higher in the Glu27Glu group vs the Gln27Gln group. The respiratory quotient (RQ) was higher in the Glu27Glu obese women along the study (P=0.046), and fat oxidation was significantly lower in this group during the recovery (P=0.048). The other variables did not differ statistically between groups.

CONCLUSION

These data suggest that both lipolysis and fat oxidation promoted by an acute submaximal exercise intervention could be blunted in the polymorphic ADRB2 Glu27Glu group of our female obese population.

Decreased invasive capacity of quinolone-resistant Escherichia coli in patients with urinary tract infections

Quinolone-resistant (QR) Escherichia coli may have lower invasive capacity than does quinolone-susceptible E. coli. To evaluate this, we prospectively collected data regarding all cases of E. coli invasive urinary tract infections (IUTI) in 669 adults admitted to the Infectious Diseases Unit of our hospital during a 3-year period, as well as 10,950 patients with cystitis or asymptomatic bacteriuria who presented to the outpatient clinic during a 1-year period. QR E. coli was isolated in 20% of patients with cystitis, compared with 8% of those with IUTI (P<.05). The proportion of E. coli isolates that were quinolone resistant was similar in patients with bacteremic and nonbacteremic IUTI. The factors of urinary manipulation and structural abnormalities were independently associated with the presence of quinolone resistance. Old age was the only variable independently associated with blood invasion. QR E. coli is less likely to produce invasive disease (pyelonephritis and prostatitis) than is quinolone-susceptible E. coli. However, once pyelonephritis or prostatitis have developed, there is no difference in the incidence of bacteremia.

Elevation of soluble interleukin-2 receptor levels in the bronchoalveolar lavage from patients with systemic sclerosis

This study was designed to investigate the levels of IL-2 and its soluble receptor (sIL-2R) in bronchoalveolar lavage fluid (BALF) from patients with systemic sclerosis (SSc). We studied 18 patients with SSc and 10 healthy volunteers. Based on high-resolution computed tomography lung scans the patients were divided into two groups, those with (SSc-ILD group, n= 10) and those without (SSc group, n = 8) evidence of interstitial lung disease (ILD). Both groups showed significantly higher total cell and neutrophil counts in the BALF than controls. The SSc group also showed significantly higher levels of lymphocytes than controls. IL-2 was not detectable in BALF. The patients showed significantly higher levels of sIL-2R than controls (77.8% vs 20%, P=0.005). The median sIL-2R levels detected did not differ between the two patient groups (SSc-ILD 270 pg/ml, SSc 232 pg/ml). This study suggests that SSc patients with or without ILD have elevated levels of sIL-2R in BALF and that in some of these patients this finding could be explained by subclinical pulmonary inflammation.

Pulmonary embolism with ST segment elevation in leads V1 to V4: case report and review of the literature regarding electrocardiographic changes in acute pulmonary embolism

A 62-year-old man presented to the Emergency Department (ED) after having three short syncopal episodes earlier that day soon after experiencing acute onset of shortness of breath. He had no significant past medical history and was a nonsmoker. Initially in the Emergency Department he was without any complaints, but then became acutely short of breath and hemodynamically unstable and died despite resuscitative efforts. His electrocardiogram showed ST segment elevations in leads V1 to V4, which is consistent with an anteroseptal myocardial infarction. Autopsy revealed that this patient did not have a myocardial infarction, but rather died of a pulmonary embolism (PE). This case demonstrates how a PE can mimic an anteroseptal myocardial infarction on electrocardiogram. This patient's lack of risk factors for PE also makes this case unusual.

Up-regulation of a thermogenesis-related gene (UCP1) and down-regulation of PPARgamma and aP2 genes in adipose tissue: possible features of the antiobesity effects of a beta3-adrenergic agonist

A number of experiments have demonstrated the antiobesity effects of beta(3)-adrenergic receptor stimulation by promoting thermogenesis and/or lipolysis. While many studies have been performed in order to develop beta(3)-adrenergic agonists as a novel strategy in the management of obesity, more information is needed about the mechanisms involved in thermogenesis and the actions of these drugs on adipocyte differentiation. To address this, the possible thermogenic and antiadipogenic properties of Tertatolol, a beta(3)-adrenergic agonist, in a diet-induced obesity model has been tested. Animals fed on a high-fat diet gained more weight and fat mass as compared with control and high-fat fed animals treated with Tertatolol. A RT-PCR was carried out in white adipose tissue specific genes involved in thermogenesis such as uncoupling proteins (UCPs) and adipogenesis such as peroxisome proliferator-activated receptor (PPARgamma2), retinoid receptors (RXRalpha/RARalpha), and fatty acid binding protein (aP2). Levels of UCP1 mRNA were augmented in the Tertatolol-treated group as compared to non-treated high-fat fed animals, while the beta(3)-adrenergic agonist treatment significantly decreased the expression levels of aP2 and transcription factors such as PPARgamma2 and the ratio RXRalpha/RARalpha as compared to obese rats. Altogether these data suggest that the antiobesity effects of beta(3)-adrenergic agonists are not limited to the promotion of thermogenesis and/or lipolysis and support the implication that these beta(3)-adrenergic agonists also affect fat deposition by impairing adipogenesis in white adipose tissue (WAT).

Early alteration in glomerular reserve in humans at genetic risk of essential hypertension: mechanisms and consequences

Essential hypertension has a familial predisposition, but the phenotype of elevated blood pressure has delayed penetrance. Because the kidney is a crucial determinant of blood pressure homeostasis, we studied early glomerular alterations in still-normotensive young subjects at genetic risk of hypertension. Thirty-nine normotensive adults (mean age 29 to 31 years), stratified by genetic risk (parental family history [FH]) of hypertension (26 with positive FH [FH+], 13 with negative FH [FH-]), underwent intravenous infusion of mixed amino acids. Before and during amino acid administration, we measured glomerular filtration rate (GFR), putative second messengers of amino acids (nitric oxide [NO.] metabolites and cGMP), serum insulin and amino acid concentrations, and the FE(Li)+ as an index of renal proximal tubular reabsorption. The FH+ group had a blunted GFR rise in response to amino acids (2.43+/-8.16% versus 31.0+/-13.4% rise, P:=0.0126). The amino acid-induced change in GFR correlated (r=0.786, P:<0.01) with the change in urinary NO. metabolite excretion; a diminished rise in urinary NO. metabolite excretion in the FH+ group (P:=0.0105) suggested a biochemical mechanism for the different GFR responses between FH groups: a relative inability to convert arginine to NO. The FH+ group had a far lower initial cGMP excretion at baseline (261+/-21.1 versus 579+/-84.9 nmol. h(-1)/1.73 m(2), P:=0.001), although cGMP did not change during the amino acid infusion (P:=0.703). FH status, baseline GFR, and baseline serum insulin jointly predicted GFR response to amino acids (P:=0.0013), accounting for approximately 45% of the variance in GFR response. Decline in FE(Li)+, an inverse index of proximal tubular reabsorption, paralleled increase in GFR (r=-0.506, P:=0.01), suggesting differences in proximal tubular reabsorption during amino acids between the FH groups. GFR response to amino acid infusion was blunted in the FH+ group despite significantly higher serum concentrations of 6 amino acids (arginine, isoleucine, leucine, methionine, phenylalanine, and valine) in the FH+ group, suggesting a novel form of insulin resistance (to the amino acid-translocating action of insulin) in FH+ subjects. We conclude that blunted glomerular filtration reserve in response to amino acids is an early-penetrance phenotype seen even in still-normotensive subjects at genetic risk of hypertension and is linked to impaired formation of NO. in the kidney. Corresponding changes in GFR and fractional excretion of Li(+) suggest that altered proximal tubular reabsorption after amino acids is an early pathophysiologic mechanism. Resistance to the amino acid-translocating actions of insulin may play a role in the biological response to amino acids in this setting. This glomerular reserve phenotype may be useful in genetic studies of renal traits preceding or predisposing to hypertension.

UCP2 muscle gene transfer modifies mitochondrial membrane potential

OBJECTIVE

The aim of this work was to evaluate the effect of uncoupling protein 2 (UCP2) muscle gene transfer on mitochondrial activity.

DESIGN

Five week-old male Wistar rats received an intramuscular injection of plasmid pXU1 containing UCP2 cDNA in the right tibialis anterior muscles. Left tibialis anterior muscles were injected with vehicle as control. Ten days after DNA injection, tibialis anterior muscles were dissected and muscle mitochondria isolated and analyzed.

RESULTS

There were two mitochondrial populations in the muscle after UCP2 gene transfer, one of low fluorescence and complexity and the other, showing high fluorescence and complexity. UCP2 gene transfer resulted in a 3.6 fold increase in muscle UCP2 protein levels compared to control muscles assessed by Western blotting. Furthermore, a significant reduction in mitochondria membrane potential assessed by spectrofluorometry and flow cytometry was observed. The mitochondria membrane potential reduction might account for a decrease in fluorescence of the low fluorescence mitochondrial subpopulation.

CONCLUSION

It has been demonstrated that UCP2 muscle gene transfer in vivo is associated with a lower mitochondria membrane potential. Our results suggest the potential involvement of UCP2 in uncoupling respiration. International Journal of Obesity (2001) 25, 68-74

Electrical injuries

Electrical injuries may occur from high or low voltage contact. Low voltage injuries usually occur in the home, tetany may lead to sustained contact, and dangerous cardiac disturbances often result. High voltage injuries are usually work related and result from brief contact but may cause serious tissue destruction and secondary injuries. Both forms may be fatal. Electrical injury more closely resembles a crush injury than a thermal injury and is managed accordingly. External manifestations often belie the severity of deeper wounds.

Protective effect of aminoguanidine in a murine model of pulmonary fibrosis induced by bleomycin

Aminoguanidine is a drug known for more than a century, which has been attracting increasing interest in recent years due to the discovery of new pharmacological properties. This study investigated the effects of aminoguanidine on the fibrotic response induced by intratracheal administration of bleomycin to rats. Three groups of animals were studied: Group A (n = 19) corresponded to the control group. Group B (n = 20) received 10 IU/kg bleomycin intratracheal, and Group C (n = 12) received the same amount of bleomycin as Group B followed by 50 mg/kg/day aminoguanidine bicarbonate for 4 weeks. Aminoguanidine led to significant reductions in total hydroxyproline content of the lungs in Group C compared to Group B (Group A: 1.83+/-0.14 mg x Group B: 3.46+/-0.36 mg x Group C: 2.09+/-0.22 mg). Morphometric collagen studies carried out on histological sections stained with Sirius red F3BA showed that aminoguanidine promoted a significant reduction of the area occupied by collagen in the axial and septal zones of the lungs (Axial region = Group A: 4.29+/-1.31% x Group B: 19.30+/-4.86% x Group C: 8.52+/-1.96%; Septal region = Group A: 0.15+/-0.06% x Group B: 0.61+/-0.21% x Group C: 0.15+/-0.06%). These results suggest that aminoguanidine is a potential therapeutic agent for the treatment and prevention of pulmonary fibrosis which is associated with different clinical conditions.