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Biomedical subjects

M Romero

Publications and source records attributed to M Romero.

At least 55 records · Page 3Linked to original sources
PubMed2001

Using a jail-based survey to monitor HIV and risk behaviors among Seattle area injection drug users.

Routine monitoring of human immunodeficiency virus (HIV) and risk behaviors among injection drug users (IDUs) is difficult outside drug treatment settings. We developed and implemented a survey of recently arrested IDUs to describe the prevalence of HIV, drug use, and sexual behaviors among them. A probability sampling survey was instituted in the King County Correctional Facility in Seattle, Washington, to sample recently arrested IDUs at the time of booking and in the jail health clinic between 1998 and 1999. Following HIV risk assessment and blood draw, additional information on drug use practices was gathered using a standardized questionnaire. Potential participants who were released from jail early could complete the study at a nearby research storefront office. Of the 4,344 persons intercepted at booking, 503 (12%) reported injection drug use, and 201 of the IDUs (40%) participated in the study. An additional 161 IDUs were enrolled in the study from the jail health clinic. Among the 348 unduplicated subjects, HIV prevalence was 2%; in the past 6 months, 69% reported two or more shooting partners, 72% used a cooker after someone else, 60% shared a syringe to divide up drugs, and 62% injected with used needles. Only 37% reported being hepatitis C seropositive, and 8% reported hepatitis B vaccination. It was feasible to conduct a jail-based survey of recently arrested IDUs that yielded useful information. The high prevalence of reported risky drug use practices warrants ongoing monitoring and illustrates the need for improving prevention programs for HIV and hepatitis B and C in this population, including expansion of hepatitis C screening and provision of hepatitis B vaccination at the jail health clinic.

Adolescent↗
PubMed2001

Expression of mosquito active toxin genes by a Colombian native strain of the gram-negative bacterium Asticcacaulis excentricus.

Mosquito control with biological insecticides, such as Bacillus sp. toxins, has been used widely in many countries. However, rapid sedimentation away from the mosquito larvae feeding zone causes a low residual effect. In order to overcome this problem, it has been proposed to clone the Bacillus toxin genes in aquatic bacteria which are able to live in the upper part of the water column. Two strains of Asticcacaulis excentricus were chosen to introduce the B. sphaericus binary toxin gene and B. thuringiensis subsp. medellin cry11Bb gene cloned in suitable vectors. In feeding experiments with these aquatic bacteria, it was shown that Culex quinquefasciatus, Aedes aegypti, and Anopheles albimanus larvae were able to survive on a diet based on this wild bacterium. A. excentricus recombinant strains were able to express both genes, but the recombinant strain expressing the B. sphaericus binary toxin was toxic to mosquito larvae. Crude protease A. excentricus extracts did not degrade the Cry11Bb toxin. The flotability studies indicated that the recombinant A. excentricus strains remained in the upper part of the water column longer than the wild type Bacillus strains.

Animals↗
PubMed2001

Restoration of a fractured primary incisor.

Esthetic restoration on primary teeth has been a special challenge to pediatric dentists. Composite restorations are the most often used treatment for decay and fractures of primary teeth, however, there are other possible alternatives. We present a case in which we have used an acrylic crown to treat a fractured primary incisor in a 1.8 years old child.

Acrylic Resins↗
PubMed2001

[Viral agents in patients with infectious processes of the central nervous system].

Local statistics report a great number of cases of neurological diseases of unidentified cause. The purpose of this research was to determine the presence of viral agents in patients with affection of the central nervous system, in Zulia State, Venezuela. In different health centers throughout the state, we collected 129 randomized samples of cerebrospinal fluid (CSF) and serum from patients ranging from 1 day to 41 years of age, showing symptoms of CNS disease and whose bacteriological test resulted negative. The serum/CSF albumin ratio was determined to exclude contaminated CSF samples, thus 54 optimal samples were obtained for the research. We determined serum IgM and CSF IgG specific for Venezuelan equine encephalomyelitis (VEE), Herpes simplex (HSV), Epstein Barr (EBV), Dengue, Rubella and Measles virus, through ELISA and indirect immunofluorescence techniques. Of the 54 samples studied, 33 (61.11%) were positive. %). The etiological agents implicated were VEE 14 cases (42.42%); HSV 11 cases (33.33%); EBV 5 cases (15.15%) and Dengue 3 cases (9.09%). We did not detect Rubella o Measles. Regarding the age distribution, the most affected group was that of children under 12 (83.34%). We analyzed the clinical manifestations and the CSF characteristics and did not find differences suggestive of an specific etiological diagnosis, even though certain signs could be considered early indications of CNS alterations due to viral causes. Our study shows that a large percentage of CNS affections of unknown etiology are produced by viral agents, indicating that in our region, most of this cases are not registered.

Antibodies, Viral↗
PubMed2000

Effect of thyroid hormones on mitochondrial oxygen free radical production and DNA oxidative damage in the rat heart.

Mitochondria seem to be involved in oxygen radical damage and aging. However, the possible relationships between oxygen consumption and oxygen radical production by functional mitochondria, and oxidative DNA damage, have not been studied previously. In order to analyze these relationships, male Wistar rats of 12 weeks of age were rendered hyper- and hypothyroid by chronic T(3) and 6-n-propyl-2-thiouracil treatments, respectively. Hypothyroidism decreased heart mitochondrial H(2)O(2) production in States 4 (to 51% of controls; P<0.05) and 3 (to 21% of controls; P<0.05). In agreement with this, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) decreased in the heart genomic DNA of hypothyroid animals to 40% of controls (P<0.001). Studies with respiratory inhibitors showed that the decrease in oxygen radical generation observed in hypothyroidism occurred at Complex III (mainly) and at Complex I; that decrease was due to the presence of a lower free radical leak in the respiratory chain (P<0.05). Hyperthyroidism did not significantly change heart mitochondrial H(2)O(2) production since the increase in State 4 oxygen consumption in comparison with control and hypothyroid animals (P<0.05) was compensated by a decrease in the free radical leak in relation to control animals (P<0.05). In agreement with this, heart 8-oxodG was not changed in hyperthyroid animals. The lack of increase in H(2)O(2) production per unit of mitochondrial protein will protect mitochondria themselves against self-inflicted damage during hyperthyroidism.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed2000

Nitric oxide production and mitochondrial dysfunction during rat thymocyte apoptosis.

Production of nitric oxide (NO) by mitochondrial membranes as methemoglobin formation sensitive to N(G)-methyl-l-arginine inhibition and mitochondrial O(2) consumption in metabolic states 3 and 4 and the respiratory control (state 3/state 4) were measured at early stages of rat thymocyte apoptosis. Programmed cell death was induced by addition of methylprednisolone and etoposide to thymocyte suspensions. Increased NO production by mitochondrial membranes was observed after 30 min of methylprednisolone and etoposide addition and was accompanied by mitochondrial respiratory impairment as an early phenomenon in apoptotic thymocytes. The respiratory control in isolated mitochondria from untreated thymocytes was 4.2 +/- 0.2 and decreased to 3.1 +/- 0.2 and 1.9 +/- 0.3 after 1 h of methylprednisolone and etoposide treatment, respectively. The low mitochondrial respiratory control was accompanied by a marked decrease in GSH and cytochrome c content. Moreover, an inhibitory effect in the amount of apoptosis due to thymocyte pretreatment with N(G)-methyl-l-arginine and N(omega)-nitro-(l)-arginine (l-NNA), indicate that nitric oxide production is closely involved in the signaling of rat thymocyte apoptosis.

Animals↗
PubMed2000

Transcatheter occlusion of complex atrial septal defects.

Percutaneous device occlusion of secundum atrial septal defects (ASDs) is becoming an accepted alternative to surgical closure. This method allows us to evaluate patients with complex conditions for treatment. From a total of 70 patients with ASD evaluated for percutaneous closure, we selected for analysis 28 who had complex conditions. The mean age was 36+/-23 yr (range, 4-72). Six had heart failure, and of these six, three had atrial fibrillation. At cardiac catheterization, the pulmonary pressure was 47+/-24 mm Hg, and the QP/QS was 1.7+/-0.4; two patients had bidirectional shunt and systemic pulmonary pressure. Two patients received a buttoned device and 26 an Amplatzer septal occluder. The groups of patients with complex conditions were separated into the following groups. Group I (n = 4) underwent combined treatment of associated anomalies. Two patients had pulmonary stenosis, one had mitral stenosis, and one had an aortic root-left atrium fistula. They were treated in or during with the same procedure by combined transcatheter techniques (balloon valvuloplasty and fistula occlusion) before ASD occlusion. Group II (n = 9) had multiple defects (cribiform or two separate holes). They were treated with a single device in five instances and with two separate devices in four cases. Group III (n = 14) had large (32+/-3 mm) single defects. Nine of them underwent successful implantation using a device 33+/-3 mm in diameter; in the remaining five patients the device was removed because of instability. Group IV (n = 3) had residual defects after previous partial device occlusion. All three defects were successfully occluded with a second device. No movement or interference with the first device was observed. Group V (n = 6) had severe pulmonary hypertension (86+/-16 mm Hg). Immediately after ASD occlusion we observed significant relief in these patients (67+/-14 mm Hg; P<0.01). There were no major complications; all 23 patients with successful implants were discharged without symptoms 2-7 days later; one patient with atrial fibrillation recovered sinus rhythm. The follow-up (8+/-5 mo) Doppler echo study showed complete ASD occlusion in 22 patients and a peak pulmonary pressure of 30+/-14 mm Hg. We conclude that transcatheter occlusion of ASDs is an effective and safe treatment for patients with complex anatomic or physiopathologic conditions, as evaluated by short-term follow-up.

Adolescent↗
PubMed2000

Modulation of ICAM-1 tissue expression in patients with liver transplantation (LT) and acute rejection (AR) after glucocorticoid treatment.

Acute rejection (AR) is a frequent complication following liver transplantation (LT). ICAM-1 may be involved in its pathogenesis. High doses of glucocorticoids are the standard treatment in these patients. The aim of this study was to describe corticoid effects on ICAM-1 tissue expression in liver biopsies of patients with LT and AR. The study included liver biopsies performed before and after treatment in 12 patients with LT and proven AR. In 10 patients AR was reversible and in 2, was steroid resistant. For immunohistochemistry, an indirect immunoperoxidase technique was used. Each histology section was semiquantitatively evaluated as follows: 0: < 10% staining, 1: 10-25%, 2: 25-50%, 3: > 50%. The control group comprised nine patients with LT and normal liver biopsies. In pre-treatment liver biopsy samples, ICAM-1 was markedly expressed on sinusoidal cells (2.41 +/- 0.66), and there was also expression on periportal (0.66 +/- 0.65) and perivenular hepatocytes (0.83 +/- 0.57). By contrast, in the liver tissue from the control group, sinusoidal ICAM-1 reactivity was significantly lower (0.88 +/- 0.33; P < 0.05), and hepatocytes showed no reliable ICAM-1 expression. After steroid treatment the intensity of ICAM-1 decreased significantly in sinusoids (1.5 +/- 0.67; P < 0.05) and in perivenular hepatocytes (0.25 +/- 0.86; P < 0.05). Additionally, we also observed a decreased ICAM-1 reactivity in portal hepatocytes (0.25 +/- 0.62), but these differences did not reach statistical significance. Remarkably, after treatment, hepatocytes did not show ICAM-1 reactivity in resolved AR, but in corticoid-resistant patients AR did not change or increase. In conclusion, in patients with LT and AR, ICAM-1 was expressed in hepatocytes and with more intensity in sinusoid cells. Additionally, a down-regulation of the ICAM-1 tissue expression after corticoid treatment may exist, although in corticoid-resistant AR no modulation on ICAM-1 tissue expression was observed.

Acute Disease↗
PubMed2000

Renal tubular acidosis and vasculitis associated with IgE deposits in the kidney and small vessels.

We report a woman with a history of allergies, polyuria, polydipsia, proteinuria, renal loss of electrolytes, renal tubular acidosis, nephrocalcinosis, and palpable purpura. A proximal defect was excluded by a normal bicarbonate reabsorption curve, and a distal tubular defect was shown because urine pH did not decrease to less than 6.4 despite ammonium chloride-induced systemic acidosis. Moreover, furosemide failed to improve urinary acidification. Urine-to-blood PCO(2) gradient was less than 14 mm Hg, although the urine bicarbonate level reached values as high as 89 mEq/L. Combining bicarbonate and neutral phosphate infusions increased the urine-to-blood PCO(2) gradient to only 20 mm Hg. These subnormal PCO(2) gradient values point to proton-pump dysfunction in the collecting tubule. Histological evidence of tubulointerstitial disease accompanied the tubular defects. The striking histological feature was the presence of immunoglobulin E (IgE) deposits in glomeruli, tubuli, and vessels. Concurrent with these findings, she had high serum IgE titers and CD23 levels. IgE antibodies from her serum were reactive against human renal tubuli, with binding to two regions that matched two different proteins present in cortex and medulla. One of these proteins corresponded to carbonic anhydrase II (31 kd); the second, to an unidentified protein that seems attached to cell membranes. We suggest that these IgE antibodies could have had a pathogenic role in this patient's glomerular, tubular, and small-vessel disease.

Acidosis, Renal Tubular↗
PubMed2000

Multicenter prospective study of children with sickle cell disease: radiographic and psychometric correlation.

After obtaining familial informed consent, between January 1996 and July 1997, 173 children (5 to 15 years old) with sickle cell disease were enrolled in a prospective multicenter study using blood screening, transcranial Doppler ultrasonography (n = 143), cerebral magnetic resonance imaging (n = 144), and neuropsychologic performance evaluation (n = 156) (Wechsler Intelligence tests WISC-III, WIPPSI-R), which were also performed in 76 sibling controls (5 to 15 years old). Among the 173 patients with sickle cell disease (155 homozygous for hemoglobin SS, 8 sickle cell beta0 thalassemia, 3 sickle cell beta+ thalassemia, 7 sickle cell hemoglobin C disease SC), 12 (6.9%) had a history of overt stroke, and the incidence of abnormal transcranial Doppler ultrasonography (defined as mean middle cerebral artery velocity > 200 cm/sec or absent) was 8.4% in the overall study population and 9.6% in patients with homozygous sickle cell anemia The silent stroke rate was 15%. Significantly impaired cognitive functioning was observed in sickle cell disease patients with a history of stroke (Performance IQ and Full Scale IQ), but also in patients with silent strokes (Similarities, Vocabulary, and Verbal Comprehension). However, infarcts on magnetic resonance imaging were not the only factors of cognitive deficit: Verbal IQ, Performance IQ, and Full Scale IQ were strongly impaired in patients with severe chronic anemia (hematocrit < or = 20%) and in those with thrombocytosis (platelets > 500 x 10(9)/L). Multivariate logistic regression analysis showed that abnormal magnetic resonance imaging (odds ratio [OR] = 2.76) (P = .047), hematocrit < or =20% (OR = 5.85) (P = .005), and platelets > 500 x 10(9)/L (OR = 3.99) (P = .004) were independent factors of cognitive deficiency (Full Scale IQ < 75) in sickle cell disease patients. The unfavorable effect of low hematocrit has already been suggested, but this is the first report concerning an effect of thrombocytosis and showing that silent stroke alone is not a factor of cognitive deficit when not associated with low hematocrit or thrombocytosis. The effect of hydroxyurea, which is known to increase hematocrit and decrease platelet count, on cognitive functioning of sickle cell patients should be evaluated prospectively.

Adolescent↗
PubMed2000

Combined percutaneous atrial septal defect occlusion and pulmonary balloon valvuloplasty in adult patients.

Severe pulmonary stenosis in association with a large atrial septal defect is uncommon. When these 2 conditions are present, significant left-to-right shunt is often prevented by the outflow obstruction, which protects the pulmonary bed until adulthood. This report shows our initial experience of percutaneous treatment of both congenital malformations, either staged or combined in the same procedure, in 2 adult patients whose treatments yielded effective atrial septal defect occlusion and right ventricular pressure relief that persisted at mid-term follow-up. Although these opposite procedures (opening and closing) have been applied as isolated methods of treatment, this preliminary experience appears to demonstrate the feasibility and effectiveness of a combined percutaneous treatment.

Adult↗
PubMed2000

Percutaneous balloon-expandable stents for sealing of acute aortic dissection.

Acute aortic dissection is a highly lethal disease. When dissection involves only the descending aorta and there are no ischemic complications, medical management may be the treatment of choice. However, a high risk of expansion or rupture of the dissection remains. When renal or limb ischemic complications do appear, surgery has been the only option, despite high mortality and morbidity. Percutaneous placement of stents for sealing an acute aortic dissection might be an alternative to surgical treatment. We treated 2 patients with acute type B aortic dissection by stent-fixation of the proximal and distal descending aorta. In both patients, there was evidence of persistent flap fixation at midterm follow-up.

Acute Disease↗
PubMed2000

Multicenter retrospective study of response to interferon in chronic hepatitis B.

AIM: The only agent known to have a lasting beneficial effect in chronic hepatitis B is interferon alpha, which achieves long-term remission in 25-40% of the patients. The goals of treatment are to induce clearance of HBV DNA from serum, to return serum aminotransferases to normal, and to improve histological findings in the liver. The most important factors predictive of response to treatment are high serum aminotranferases levels, low serum HBV DNA concentrations, and active histologic changes on liver biopsy. The aim of this study was to assess the response to interferon alpha in patients with chronic hepatitis B and to analyze the factors predictive of response. METHODS: We conducted a multicenter retrospective study to investigate the effect of interferon treatment in 132 patients with chronic hepatitis B in overall terms and based on HBeAg, and factors predictive of response. RESULTS: A overall sustained response was noted in 59 of 132 interferon-treated patients (45%) and 61 patients were nonresponders (46%). 12 patients relapsed (9%). None of the patients had negative HBsAg. No difference was observed in the response rate between the two treatment groups (HBeAg-positive and HBeAg-negative patients). Overall, high initial levels of serum AST and ALT predicted a good response. Age and liver biopsy findings were factors predictive of response in HBeAg-positive and HBeAg-negative patients respectively. Sex, epidemiological factors, treatment and type of virus did not correlate with the response to interferon. CONCLUSIONS: A sustained response to interferon alpha was observed in 45% of the patients with chronic hepatitis B. HBeAg seroconversion was found in up to 50% of HBeAg-positive patients. None of the patients had negative HBsAg. Overall, the response rate was higher in patients with high pretreatment serum aminotransferase levels. Age was the predictive factor in HBeAg-positive patients, and histological features were predictive in the HBeAg-negative group. However, further studies in a larger patient population are necessary to obtain well-substantiated conclusions.

Adolescent↗
PubMed2000

Surgical solutions to periodontal complications of orthodontic therapy.

Collaboration of various specialists has become essential in pediatric dental practice. In orthodontics, this collaboration is completely necessary when the patient presents periodontal problems. Even in healthy patients, who do not suffer from periodontal disease, periodontal complications may occur during treatment with fixed appliances. Two cases of young patients, in which periodontal procedures were used to complement the results of orthodontic treatment are presented.

Adolescent↗
PubMed2000

[Smoking among academics, non-academics and students of the Universidad de Concepción].

BACKGROUND: Effective smoking cessation campaigns require as baseline, precise estimations of smoking habits in different populations. AIM: To assess the prevalence of smoking in academic, non-academics workers and student of the University of Concepción. MATERIAL AND METHODS: In a random and stratified sample of 272 workers (including academics) and 1146 students, a previously validated, self administered questionnaire about smoking was applied. Daily smoking was defined as smoking seven or more cigarettes per week and occasional smoking as smoking less than seven cigarettes per week. RESULTS: The prevalence of smoking was 23% among academics, 34% among non-academic workers and 44% among students. Nineteen percent of men and 16% of women were occasional smokers; 23% of men and 25% of women were daily smokers. Students started smoking at 15 +/- 2 years old and workers did so at 18 +/- 3 years old. The greater influence about smoking came from parents. Workers from the administrative services and from the natural sciences faculty had the higher prevalence of the habit. The total annual cost of smoking was $33,000,000 (US$62,000). CONCLUSIONS: The prevalence of smoking at the University of Concepción is higher among students than workers. Quitting programs are urgently needed.

Adolescent↗