Nicotine modulates molecules of the innate immune response in epithelial cells and macrophages during infection with M. tuberculosis.

Smoking increases susceptibility to becoming infected with and developing tuberculosis. Among the components of cigarette smoke, nicotine has been identified as the main immunomodulatory molecule; however, its effect on the innate immune system is unknown. In the present study, the effect of nicotine on molecules of the innate immune system was evaluated. Lung epithelial cells and macrophages were infected with Mycobacterium tuberculosis (Mtb) and/or treated with nicotine. The results show that nicotine alone decreases the expression of the Toll-like receptors (TLR)-2, TLR-4 and NOD-2 in all three cell types, as well as the production of the SP-D surfactant protein in type II pneumocytes. Moreover, it was observed that nicotine decreases the production of interleukin (IL)-6 and C-C chemokine ligand (CCL)5 during Mtb infection in epithelial cells (EpCs), whereas in macrophages derived from human monocytes (MDMs) there is a decrease in IL-8, IL-6, tumor necrosis factor (TNF)-α, IL-10, CCL2, C-X-C chemokine ligand (CXCL)9 and CXCL10 only during infection with Mtb. Although modulation of the expression of cytokines and chemokines appears to be partially mediated by the nicotinic acetylcholine receptor α7, blocking this receptor found no effect on the expression of receptors and SP-D. In summary, it was found that nicotine modulates the expression of innate immunity molecules necessary for the defense against tuberculosis.

The triglycerides and glucose index is associated with cardiovascular risk factors in metabolically obese normal-weight subjects.

PURPOSE: The aim of this study was to determine whether the triglycerides and glucose (TyG) index is associated with the presence of metabolically obese normal-weight (MONW) phenotype and related cardiovascular risk factors. METHODS: Apparently healthy men and non-pregnant women aged 20-65 years were enrolled in a population-based cross-sectional study. Overweight, obesity, smoking, alcohol consumption, pregnancy, diagnosis of hypertension, diabetes, cardiovascular disease, liver disease, renal disease, malignancy, and medical treatment were exclusion criteria. Subjects were allocated into the MONW or normal-weight groups. MONW phenotype was defined by normal weight and the presence of at least one of the following cardiovascular risk factors: elevated blood pressure, hyperglycemia, hypertriglyceridemia, and low HDL cholesterol. RESULTS: A total of 542 subjects were enrolled and allocated into the MONW (n = 354) and normal-weight (n = 188) groups. The adjusted logistic regression analysis showed that the elevated TyG index is significantly associated with the presence of MONW phenotype (OR = 11.14; 95% CI 6.04-20.57), hyperglycemia (OR = 3.18; 95% CI 1.95-5.21), hypertriglyceridemia (OR = 399.19; 95% CI 94.01-1694.98), and low HDL-C (OR = 2.60; 95% CI 1.74-3.87), but not with elevated blood pressure (OR = 1.55; 95% CI 0.93-2.60). CONCLUSION: Results of this study support that the TyG index may be a useful indicator to detect MONW phenotype and associated cardiovascular risk factors.

Polymorphisms in the GSTT1 and GSTM1 genes are associated with increased risk of preeclampsia in the Mexican mestizo population.

Preeclampsia is a pregnancy-specific disorder in humans and a major cause of maternal and neonatal morbidity and mortality. Increasing evidence suggests that oxidative stress plays an important role in the pathogenesis of preeclampsia. The aim of this study was to investigate the relationship between null alleles of the glutathione S-transferases (GST) M1 and T1 genes and the risk of preeclampsia. This case-control study involved 112 preeclamptic and 233 normoevolutive pregnant women. The null polymorphisms were genotyped by multiplex polymerase chain reaction (PCR). Our results showed an increased risk of preeclampsia in patients with the GSTT1 null genotype [odds ratio (OR) = 2.21; 95% confidence interval (CI) = 1.14-4.27; P = 0.018]. Our data further showed that a combination of deletion genotypes of the GSTM1 and GSTT1 genes conferred an even higher risk of preeclampsia (OR = 4.56, 95%CI = 1.59-13.09; P = 0.005). Our results provide the first evidence suggesting that a GSTT1 null polymorphism might be associated with preeclampsia in the Mexican mestizo population, and that this risk increases with the combination of both GSTT1 and GSTM1 null polymorphisms.

Effects of aflatoxin chronic intoxication in renal function of laying hens.

Aflatoxins (AF) have a high impact in both human and animal health, causing significant economic losses in the poultry industry, especially by diminution of avian growth, feed efficiency, and product quality. Aflatoxins affect the whole organism, particularly liver and kidney. The objective of this study was to evaluate renal function alterations in laying hens during chronic AF ingestion. Randomly, 84 Leghorn Hy-Line laying hens (13 wk old) were assigned into 4 experimental groups (n = 21): 0.0, 0.5, 1.0, and 1.5 mg of AF/kg of feed. The AF (B(1), B(2), G(1), and G(2)) was obtained from 2 toxicogenic local strains of Aspergillus flavus grown in corn grains; the grain was sterilized, ground, and added to basal diets to achieve the selected AF concentrations. Hens ingested, during 17 and 42 wk, feed contaminated with AF. Data were analyzed in a 4 x 2 factorial arrangement. Hens were anesthetized, ureteral urine samples were collected, and arterial blood samples were taken. The renal functional tests were evaluated by spectrophotometric and flame photometric methods, including a) Na, K, Ca, and phosphate fractional excretions; b) renal hemodynamic studies, glomerular filtration rate and renal plasma flow by inulin and p-aminohippurate clearances, respectively; and c) identification of macroscopic and histopathologic lesions. The hens intoxicated at all levels of AF showed significant (P < 0.05) increases in Ca, Na, and phosphate fraction excretions. Sodium and phosphates were excreted in a pattern of response time-dose. However, glomerular filtration rate exhibited a significant reduction (P < 0.05). The K fractional excretion and renal plasma flow remained unchanged. These results suggest that AF chronic ingestion affects renal functions of laying hens and induces Ca(++), (-3)PO(4), and Na(+) losses, which are of great concern to the poultry industry.

The Ginkgo biloba extract (GbE) protects the kidney from damage produced by a single and low dose of carbon tetrachloride in adult male rats.

Gingko biloba leaves have been used as herbal medicine in China for 5000 years, and the standardized leaf extract (GB-STE) has some beneficial effects in the treatment of age-related, cardiovascular, and neurological diseases. The aim of this study was to investigate the renoprotective effects of the Gingko biloba extract (GbE) against the toxicity of a single and relatively low dose of carbon tetrachloride (CCl4). In male adult Wistar rats, we determined the urine flux, the concentration of total proteins in urine, the concentration of glucose in urine, and the concentration of malondialdehyde (MDA) in renal cortex as well as two markers of renal function (clearance of inulin and p-aminohippurate); we also compared the histological lesions caused by CCl4. Carbon tetrachloride increased the urinary concentration of total proteins, and the renal concentration of MDA; however, it did not modify the urine flux, urinary concentration of glucose, nor the inuline or the p-aminohipurate clearances. Morphologically, CCl4 generated some tubular damage that was more intense in the inner cortex of kidneys. The GbE extract counteracted the effects of CCl4 on the concentration of total proteins in urine, the concentration of renal MDA, and the renal histological changes. In conclusion the main toxic effects produced by CCl4 were prevented by the GbE, probably due to their antioxidant properties and the inhibition of the main P450 isoenzyme (CYP2E1) that metabolize CCl4.

A randomized trial comparing two corticosteroid regimens combined with mycophenolate mofetil and cyclosporine for prevention of acute renal allograft rejection.

INTRODUCTION: The launching of mycophenolate mofetil (MMF) has reduced the incidence of acute rejection episodes. We sought to evaluate the efficacy of decreasing the steroid dose. MATERIALS AND METHODS: This was a quasiexperimental, randomized, prospective trial. We enrolled 150 patients who received de novo renal transplantations from living or cadaveric donors, fulfilling the screening criteria. Patients were randomized to one of the following two arms: (A) MMF at a 2 g/d dose, cyclosporine (CsA) at a dose necessary to achieve target levels, and corticosteroids at the usual doses; (B) MMF at a 2 g/d dose, CsA at a dose necessary to achieve target levels, and corticosteroids at doses 50% lower than those of group A. RESULTS: Group A included 72 (48%) and group B, 78 patients (52%). There were no differences among the variables: leukopenia occurred in 11 patients in group A, and five patients in group B. Complications occurred in 67.4% (56) of group A, but only 32.6% (27) were related to infections. One case of urinary infection occurred in group B, while six occurred in group A. There was one case of acute rejection in group A, and none in group B. One graft loss occurred in group A. There were no differences in the remaining variables under study. DISCUSSION: The results showed an increased complication rate related to receiving usual steroid doses. There was no increase in acute rejection episodes among patients receiving 50% of the usual steroid dose.

The ATP levels in kidneys and blood are mainly decreased by acute ingestion of tullidora (Karwinskia humboldtiana).

Our previous acute toxicity studies with Karwinskia humboldtiana (Kh) in rats showed renal hemodynamic changes with a marked increase in the fractional excretion of sodium and morphological damage. To analyse the effects of Kh or 'tullidora' on energetic metabolism, a single dose of an oral preparation from the seed fruits was given to Wistar rats (1.25 g/kg). In tullidora-treated rats there was 8% mortality. ATP concentrations in renal tissue decreased significantly (control: 53.85+/-3.34, tullidora 38.28+/-5.31 micromol/g fresh tissue, P<0.05). Total blood (54.8+/-0.96, tullidora: 40.2+/-1.55 micromol/dL, P<0.01) and haemoglobin-ATP concentrations (3.69+/-0.12, tullidora: 2.56+/-0.11 micromol/g, P<0.01) were also significantly diminished. Moreover, the total protein in renal cortex from tullidora-treated rats decreased as compared to control group (control: 71.43+/-2.88, tullidora: 55.20+/-4.06 mg/g fresh tissue, P<0.05). In contrast, Na+-K+-ATPase activity in tullidora-treated animals was not different from control rats. These findings might partially explain the acute effects and mortality observed in the Kh treated rats.

Safety assessment of the conversion from mycophenolate mofetil to enteric-coated mycophenolate sodium in stable renal transplant recipients.

The immunosuppressant mycophenolate mofetil (MMF; CellCept) has greatly improved transplant recipients' clinical outcomes, but its efficacy may be limited by dose adjustments due to adverse events (AEs). An enteric-coated formulation of mycophenolate sodium (EC-MPS; myfortic), designed to improve gastrointestinal tolerability is now available. This Latin-American, prospective, multicenter, open-label, 6-month trial assessed the safety and tolerability of converting renal transplant recipients from MMF to EC-MPS. In total, 237 renal transplant recipients (stable > or = 3 months' posttransplant) receiving MMF (< or =1000 mg b.i.d.) were enrolled. Adults (n = 218) were converted to EC-MPS 720 mg b.i.d. (equimolar to MMF 1000 mg b.i.d.) even if they were initially receiving <1000 mg MMF b.i.d. (ie, 47 adults received a higher than equimolar dose of EC-MPS). Children (n = 19) were converted to EC-MPS 450 or 432 mg/m2 b.i.d. Patients also received cyclosporine microemulsion (Neoral) and corticosteroids. There were three acute rejections and no graft failures. The incidence of AEs was 59.9% (in those receiving a higher than equimolar EC-MPS dose it was 57.4%). In all, 22% of patients had gastrointestinal AEs, 37% had infections, and 4.8% had hematological AEs. Only 24 patients (10%) had an AE-related dose reduction. Seven of these patients had received higher than equimolar doses of EC-MPS. Patients can be safely converted from different doses of MMF to a standard dose of EC-MPS. The requirement for EC-MPS dose reduction to manage AEs was relatively low. Use of EC-MPS is a valid alternative for renal transplant recipients receiving maintenance MMF treatment.

Electronic microscopy and EDX characterization of Teotihuacan prehispanic mortar from the cave under the Sun Pyramid.

A cave (102 m long) under the structure of the Sun pyramid of the prehispanic Teotihuacan City indicates the importance of the pyramid. Studies of the cave mortar samples using energy dispersive X-ray (EDX) fluorescence, scanning electron microscopy (SEM) and X-ray diffraction (XRD) showed no difference in the chemical elemental composition. The elements can be distributed in three groups: major, minor and trace elements. The minerals identified were compatible with the origins of the cave and with the magnetic pattern.

[Comparative study between cystoscopy, urinary cytology, NMP-22 and a new method, bladder chek, in the follow-up of superficial bladder cell carcinoma]. / Estudio comparativo entre cistoscopia, citología urinaria, NMP-22 y un nuevo método, bladder chek, en el seguimiento del cáncer vesical superficial.

OBJECTIVE: The goal of this work tries to evaluate the utility of the qualitative determination of NMP-22 in the evaluation of the superficial bladder carcinoma in asymptomatic patients, comparing it with its quantitative determination, the cytology and the cystoscopy. MATERIALS AND METHODS: A simple of urine just voided was taken in 88 asymptomatic patient follow-up for superficial bladder cell carcinoma. This dose was distributed in 3 parts, for performed cytology, for determination of NMP-22, and 4 drops of the third part are added to device bladder chek. Later, we performed cystoscopy and transurethral resection in patients with a suspicion of bladder cancer. RESULTS: 26 patients had tumor relapse and 62 patients were free of disease. The sensitivity for the bladder chek was of 28%, 34.62% for NMP-22, 34.62% for cytology and 100% for cystoscopy. The specificity was of 93.55%, 80.33%, 87.10% and 87.10% respectively. The sensitivity by degree was 25 in G1, 28.57 in G2 and 50 in G3 for Bladder chek; 29.41, 42.86 and 50 for NMP-22; 23.53, 71.43 and 0 for cytology. The sensitivity by stages was 27.7 in Ta-1 and 50 in T2 for Bladder chek; 34.78 and 50 for NMP-22; 39.13 and 0 for the cytology. CONCLUSIONS: The low sensitivity of bladder chek invalidates it like alternative method to the cystoscopy in the follow-up of the superficial asymptomatic bladder cell carcinoma.

Influence of sex differences on the renal secretion of organic anions.

The kidney's responsiveness to male sexual hormones has been often neglected. Renal secretion of organic anions is higher in male than in female individuals; as a consequence, most of the xenobiotics that are excreted from the organism through this pathway are eliminated more rapidly by males than by female animals. To gain further insight into this issue, we studied in vitro and in vivo characteristics of the transport of p-aminohippurate (PAH), a suitable marker for this system, in male and female rats, under different hormonal conditions. Kinetics of PAH showed a shorter elimination half-time in male than in female rats (t(1/2el): male = 16.2 +/- 2.1 min, female = 25.7 +/- 4.5 min, P < 0.05). Castration of male rats increased t(1/2el) to a value similar to that of female rats (t(1/2el): orchiectomized rat = 28.1 +/- 7.1 min). Testosterone treatment of female rats increased the elimination rate to a value similar to that of male rats. In vitro PAH uptake by renal cortical slices from intact male rats was higher than that by slices from orchiectomized rats. Kinetic analyses of PAH uptake suggest that the difference was caused by a lower number of transporting molecules in orchiectomized than in intact animals, whereas the transporting capacity for each carrier was similar in male and in orchiectomized rats. Our results suggest that testosterone increases the number of functional carriers for PAH in the kidney.

Efficacy of oral tegafur modulation by uracil and leucovorin in advanced colorectal cancer. A phase II study.

A phase II study was performed to assess the efficacy and toxicity of UFT (tegafur-uracil in the molar ratio 1:4) modulated with leucovorin (LV) in previously untreated patients with advanced colorectal carcinoma (CRC). 79 patients with measurable advanced colorectal cancer (CRC) and no prior chemotherapy were included. 75 patients were evaluable for toxicity and response. The regimen consisted of LV 500 mg/m2 administered intravenously on day 1, followed by oral UFT 390 mg/m2 on days 1-14. Patients received oral LV 15 mg every 12 h on days 2-14. Treatment was repeated every 28 days for a minimum of four courses per patient. Three hundred and ninety-eight cycles of chemotherapy were delivered (median five per patient). 7 patients (9%) had a complete response, and 22 a partial response for an overall response rate of 39%. Mild gastrointestinal toxicity was dose limiting: grade 3-4 diarrhoea appeared in 9% of patients. Other grade 3-4 toxicities were nausea/vomiting and mucositis in 4% of patients, gastric pain and leucopenia in 3%. Oral UFT modulated by oral LV is active in advanced CRC and can be administered on an outpatient basis with no significant toxicity requiring hospitalisation. Given its excellent tolerance profile and low toxicity, the regimen should be thoroughly studied and compared with 5-fluorouracil modulated by LV.

Glutathione S-transferases and esterases in placenta after normal and pre-eclamptic pregnancies.

Severe pre-eclampsia reduced significantly (P<0.05) by 68+/-6 per cent (mean+/-sem, n=10) the maximal velocity (V(max)) and, consequently, reduced significantly by 60+/-7 per cent the catalytic efficiency (C(E)) of placental glutathione transferase pi, assayed with ethacrynic acid. Mild and severe pre-eclampsia reduced significantly by 82+/-5 per cent (mean+/-sem, n=5) and by 41+/-5 per cent (mean+/-sem, n=10), respectively, the V(max)and, consequently, reduced significantly by 72+/-7 and by 33+/-13 per cent, respectively, the C(E)of esterase, assayed with p-nitrophenyl acetate. Furthermore, severe pre-eclampsia increased significantly by 296+/-78 per cent the Michaelis-Menten constant (K(m)) of total GST, assayed with chlorodinitrobenzene and, consequently, decreased significantly the C(E)by 83+/-3 per cent. On the other hand, the concentrations of total and non-protein thiols did not change significantly in placental homogenates from patients with mild or severe pre-eclampsia compared to normal pregnancies. These findings would indicate a decreased capacity of the glutathione transferases and esterase detoxification systems to protect the fetus from drugs prescribed to pregnant women suffering pre-eclampsia, mainly in the severe phase.

Ten years of selective shunts for hemorrhagic portal hypertension.

Selective portosystemic shunts have been performed in our hospital since 1973 for the treatment of variceal bleeding secondary to portal hypertension. We report our experience in 139 selective operations performed in a 10-year period (1973 to 1983). One hundred thirty patients underwent elective nine underwent emergency surgery. Eighty-five patients were classified in the A functional group of Child, 42 in group B, and 12 in group C. The overall mortality rate in the emergency group was 44% and in the elective group, 13%. Ascitis and transitory hepatic failure were the most common postoperative complications. The long-term follow-up clinical encephalopathy rate was 16%. The survival rate according to the Kaplan-Meier survival analysis was 80% at 2 years, 68% at 5 years, and 67% at 10 years.

Drug use pathways among high school students of Mexico.

OBJECTIVE: This study surveyed high school student drug users in urban areas of Mexico to describe use patterns and drug-related behaviors among adolescents and to develop predictor models of pathways to underage drug use. SUBJECT/DESIGN: A National School Survey was conducted among high school students where data are provided by the State. Only urban sites were considered for this study (n = 40,521). Stratified two-stage cluster sampling was used; schools and groups within the schools were the sampling units. CONCLUSIONS: Male adolescents who have worked the previous year, have high exposure within the family and are affiliated with drug using peers are at increased risk of becoming drug users and subject to depression and suicidal ideation as well as drug-related social problems.

Sugiura procedure outside Japan. The Mexican experience.

In the last 10 years, we operated on 231 patients with hemorrhagic portal hypertension. Most of these patients had some form of liver disease. We performed various surgical procedures: 47 conventional shunts with H grafts and terminolateral portacaval shunts with arterialization of the portal stump, 139 selective Warren shunts, and in those patients in whom a selective portasystemic shunt could not be performed for technical reasons, esophagogastric devascularization in the form of the Sugiura procedure. Forty-five patients were treated with the Sugiura procedure as a one stage or two stage procedure. A total of 68 emergency and elective operations were performed. The operative mortality rate for the emergency thoracic operation was 41 percent and for the abdominal operation, 42 percent. The overall operative mortality rate in the emergency group was 41 percent. The incidence of recurrent variceal bleeding and encephalopathy was 0 in the surviving patients. The survival rate at 3 year follow-up was 40 percent. The elective group was made up of 24 patients. Eighteen patients had a two stage procedure and 6 patients had a one stage procedure. The operative mortality rate for the abdominal operation was 11 percent, whereas that for the thoracic operation was 7 percent. The operative mortality rate for the one stage procedure was 16 percent. The overall operative mortality rate in the elective group was 10.8 percent. None of these patients had recurrent variceal bleeding and encephalopathy developed in only one (5 percent). The encephalopathy was easily controlled with medical treatment. The 3 year survival rate was 83 percent. We conclude that the Sugiura procedure is an effective procedure to treat hemorrhagic portal hypertension when a selective shunt cannot be performed.

Structural improvement of higher education in environmental toxicology in Latin America and Europe.

Industrial development has resulted in an increased release of chemicals and other agents into the environment, resulting in damage to the environment as well as increasing the risk of adverse effects on human health. Environmental toxicology (ET) is the discipline responsible for assessing the risks to human health and the environment from the effects of new chemicals and those already present in the environment. The development of human resources in toxicology is therefore a priority in both Latin America (LA) and the European Union (EU), although LA professionals are more involved in risk evaluation than in risk assessment compared to their EU colleagues. A solid background in general toxicology will enable those interested in environmental issues to tackle local problems. Moreover, the increasing globalization of markets and, therefore, of the necessary regulations, requires harmonisation of postgraduate programmes to ensure that risk assessment and management related to the environment are dealt with uniformly and by highly qualified scientists. The Inaugural Meeting of the ALFA-OMET Toxicology', a 2-year programme supported by the European Commission, offered the opportunity to discuss a number of these issues. The present status of existing ET courses in the EU and LA and the corresponding professional profiles in the two regions were examined, and a harmonized academic curriculum for a postgraduate professional profiles in the two regions were examined, and a harmonized academic curriculum for a postgraduate course in environmental toxicology was developed. Finally, a course programme for toxicology and a specialization in environmental toxicology designed by a panel of experts was discussed, and its relevance as a model for other specialisation programmes was analysed. Exercises such as those performed by ALFA-OMET may be useful not only in promoting discussion for the implementation of national and international professional registers in LA, but also in encouraging the same, ongoing process in the EU.

Stable renal transplant recipients can be safely converted from MMF to enteric-coated mycophenolate sodium tablets: Interim results of a multicenter Latin American study.

Enteric-coated mycophenolate sodium (EC-MPS) is designed to reduce mycophenolate acid (MPA)-related upper gastrointestinal (GI) adverse events (AEs). A multicenter, open-label, Latin American study in stable renal transplant patients is ongoing to assess the safety of the conversion from mycophenolate mofetil (MMF) to EC-MPS. An interim analysis was performed when 93 patients had completed 3 months. Prior to conversion, they had received MMF at a dose of 2 g/d, with the exception of eight adult patients who were receiving an average daily dose of 1.25 g. All adult patients were converted to EC-MPS (1.44 g/d; 0.450 g/m(2) bid for children). After conversion, the reported total incidence of AEs was 40.9%, including 28% infections, 1.1% hematologic, 19.4% GI, including 10.8% upper-GI AE (all mild) and 5.4% diarrhea. No patient discontinued the study medication due to adverse events. Only six patients (6%) required a dose adjustment. There were no episodes of acute rejection, death, or graft loss. During the period of analysis, the conversion from MMF to EC-MPS was safe, the enteric-coated tablet formulation prevented release of MPA in the upper GI tract, and only one patient had to reduce the dose due to an upper GI AE, concomitant with diarrhea. EC-MPS offers transplant physicians and their patients an alternative MPA therapy that is as effective and safe as MMF, but in a formulation that may provide GI tolerability benefits.

Distribution, origin and fate of chromium in soils in Guanajuato, Mexico.

Total, hexavalent and trivalent chromium were determined in surface and 30-cm depth soil samples from a highly chromium-polluted area in Guanajuato state, central México. Four samples were also analyzed by a sequential extraction procedure. Nearly 0.9 km(2) out of the 8 km(2) area sampled was polluted with chromium, at concentrations up to 12960 mg kg(-1), mostly as Cr(III). Concentrations of Cr(VI) were lower than 0.5 mg kg(-1) in most sampled points, with the exception of one, where the concentration was found to be 65.14 mg kg(-1). Chromiumcontaining dust from a chromate factory accounted for most of the contamination. The highest concentrations of hexavalent chromium in soil, were in the bottom sediments of an abandoned water reservoir used to store polluted water from a well, before use of the water in the factory process. Tannery wastes, dust from a sanitary landfill of chromate compounds and the transport of chromium products are the sources of chromium at other sites. Chromium is fixed preferentially in the hydrous Fe and Mn oxides in the more polluted soils. Less polluted soils have a high proportion of chromium associated with the sulfide and organic fraction. Cr(III) is retained preferentially in the superficial soil layer. Variations in the physical characteristics of the soil, relative abundance of the various soil components and characteristics of the contaminant source, give rise to differences in chromium soil concentrations with depth.

[Intravascular ultrasonographic evaluation of direct stents, implanted without predilatation. Comparison of results according to lesion types]. / Evaluación con ultrasonografía intravascular de stents implantados sin predilatación (stents directos). Comparación de resultados según el tipo de lesión.

INTRODUCTION AND OBJECTIVES: Direct stenting is a safe and feasible technique in selected lesions yielding excellent angiographic results. However, there are no studies providing intravascular ultrasonographic examination after direct stenting. The aim of this study was to evaluate direct stent expansion with ultrasonography and to know whether there are differences in the results based on lesion types. METHODS: Patients with amenable lesions for direct stenting were enrolled; including patients with no occlusion, no calcification, no significant tortuosity or angulation, a length 15 mm and a reference lumen diameter 2.5 mm. Intravascular ultrasonography was performed after stent implantation. The ultrasonographic criteria for optimal expansion were: complete apposition and a minimal intrastent lumen area > 80% of the average reference luminal area and 90% of the distal reference lumen area. RESULTS: We included 40 patients (50 lesions). The final angiographic result was good in all the patients but in one case an additional stent was used due to dissection. The ultrasonographic examination did not show significant differences between type A and B lesions. Optimal expansion was achieved in 14/21 (66%) of type A lesions and 17/29 (58%) of type B lesions (p = 0.5). The balloon/artery ratio was the only factor significantly related to ultrasonographic results. When this ratio was 1.1-1.2 (25 cases), 76% of the stents were optimally expanded and when the ratio was < 1. 1 (25 cases) only in a 48% an optimal result was achieved (p < 0.05). CONCLUSIONS: Direct stenting in selected lesions provides ultrasonographic results comparable to those expected with conventional stenting and these results could be even improved if a balloon artery ratio 1.1-1.2 is used. Taking into consideration the selection criteria the differences observed between lesion types A and B are not significant.