Biomedical subjects

J M Marin

Publications and source records attributed to J M Marin.

At least 19 recordsLinked to original sources

PubMed2006

The 6-min walking distance: long-term follow up in patients with COPD.

The 6-min walking distance (6MWD) test is used in clinical practice and research into patients with chronic obstructive pulmonary disease (COPD). However, little is known about natural long-term change in this parameter. The 6MWD was measured at baseline and then annually for 5 yrs in 294 patients with COPD and its annual rate of decline was determined. Forced expiratory volume in one second (FEV1) was also measured and the relationship between changes in both markers was explored. At baseline, the median 6MWD was 380 m (range 160-600 m). It declined by 19% (16 m.yr(-1)) over the 5 yrs compared with baseline in patients with American Thoracic Society/European Respiratory Society stage III COPD (FEV1 30-50% predicted) and by 26% (15 m.yr(-1)) in patients with stage IV COPD (FEV1 <30% pred). Over the 5-yr follow-up, the proportion of patients with a minimal clinically significant decline of 54 m increased with the severity of the disease. It was 24% in stage II, 45% in stage III, and 63% in stage IV disease. In contrast, the rate of decline of FEV1 was greater in patients with milder airflow obstruction and lesser in patients with lower absolute FEV1 values. In conclusion, the 6-min walking distance test provides increasingly useful information as the severity of chronic obstructive pulmonary disease increases.

Adult↗

PubMed2006

Characterization of Escherichia coli isolated from carcasses of beef cattle during their processing at an abattoir in Brazil.

Beef carcass sponge samples collected between March 2003 and August 2005 at an abattoir in Brazil were surveyed for the presence of Shiga toxin-producing Escherichia coli (STEC). Only one carcass among the 80 tested showed a STEC, stx2-encoding gene by PCR amplification. The frequency of carcass contamination by E. coli during processing was tested at three situations, respectively: preevisceration, postevisceration and postprocessing, during the rain and dry seasons. The prevalence of E. coli at the three points was of 30.0%, 70.0%, 27.5% in the rain season and of 22.5%, 55.0%, 17.5% during the dry season, respectively. The E. coli isolates exhibited a high level (45.0%) of multidrug resistance to two or more antimicrobial agents.

Abattoirs↗

PubMed2004

The incidence of Shiga toxin-producing Escherichia coli in cattle with mastitis in Brazil.

AIMS: To determine the prevalence and molecular characteristics of Shiga toxin-producing Escherichia coli (STEC) isolates from bovine mastitic milk in Brazil. METHODS AND RESULTS: A total of 2144 milk samples from dairy cattle showing mastitis were screened for the presence of E. coli. A total of 182 E. coli isolates were selected and examined. All were subjected to dot blot analysis using the CVD419 probe for the detection of the enterohaemolysin (hly) gene, and to a multiplex PCR for the detection of stx1, stx2 and eaeA genes. STEC were isolated from 22 (12.08%) milk samples. All the STEC isolates were tested for sensibility to 10 antimicrobials; the resistances most commonly observed were to cephalothin (86.3%), tetracycline (63.6%) and doxycycline (63.6%). CONCLUSION: STEC isolates were found in bovine mastitic milk in Brazil. SIGNIFICANCE AND IMPACT OF THE STUDY: STEC isolates from mastitic milk were potentially pathogenic for human in that they belonged to serogroups associated with diarrhoea and haemolytic-uraemic syndrome, some of them were stx2, eaeA and hly positive.

Adhesins, Bacterial↗

PubMed2003

Determination of abamectin and azadirachtin residues in orange samples by liquid chromatography-electrospray tandem mass spectrometry.

A rapid and sensitive LC-ESI-MS-MS method has been developed for the determination of azadirachtin and abamectin residues in orange samples. Samples were extracted with acetonitrile, in a high-speed blender. After the addition of sodium acetate, an aliquot of extract was directly injected into the LC-ESI-MS-MS system. The highest sensitivity of the method was achieved under MS-MS conditions using [M+Na]+ adducts as precursor ions. Recoveries for both compoundsfrom spiked orange samples at 0.01 and 0.1 mg/kg were above 80%, with good repeatability (<10%). Method detection limits achieved (<0.007 mg/kg) were adequate for the determination of these pesticides in this kind of sample from the regulatory point of view. The importance of the solvent used for extraction, as well as the addition of sodium acetate to the extracts and the selection of adequate chromatographic conditions are discussed.

Chromatography, Liquid↗

PubMed2002

O-serogroups, eae gene and EAF plasmid in Escherichia coli isolates from cases of bovine mastitis in Brazil.

Mastitis has been recognized for some time as the most costly disease in dairy herds. From March 1997 to August 1998, 2144 samples of bovine mastitic milk were collected, from which 182 Escherichia coli isolates were made, and from which 141 isolates had the somatic antigen (serogroup) determined. Twelve different serogroups were isolated from mastitic milk, and among them were O26, O55, O111 and O119, all of them classic enteropathogenic E. coli (EPEC) serogroups. These represented 40.0% of the isolates. The 20 of 57 isolates tested had plasmids and in dot blot hybridization, nine isolates were positive for an EaeA probe and an EPEC adherence factor (EAF) probe while two isolates were negative for EaeA probe but positive for the EAF probe. The nine isolates were characterized as attaching and effacing (A/E) E. coli (AEEC) isolates.

Adhesins, Bacterial↗

PubMed2001

Natural evolution of Elschnig pearl posterior capsule opacification after posterior capsulotomy.

PURPOSE: To study the natural evolution of Elschnig pearl posterior capsule opacification (PCO) after neodymium:YAG posterior capsulotomy. SETTING: Instituto Oftalmológico Murciano, Murcia, Spain. METHODS: This prospective study comprised 173 eyes that had a posterior capsulotomy to treat Elschnig pearl PCO. Patients were included in the study at different stages after posterior capsulotomy and followed using serial anterior segment photographs for 18 to 48 months. RESULTS: During the first year after the capsulotomy, pearls proliferated and migrated toward the capsulotomy edge in 83% of the cases, leading to the formation of a collar-like ring of pearls around the capsulotomy. During the second year, an increase in cells was observed in 45% of cases; in 45% of eyes, there were fewer pearls. The amount of pearls decreased in 48%, 52%, and 26% of cases at 3, 4, and 5 years, respectively, and were completely gone in 6%, 17%, and 45%. After 5 years, 17% of eyes had a reduction in pearls and 67% had no pearls. CONCLUSIONS: Elschnig pearl PCO is a self-limiting process. After posterior capsulotomy, cells proliferated and attempted to occlude the capsular opening. Later, a reduction in the amount of cells was observed, leading to a completely clear posterior capsule in most eyes.

Adolescent↗

PubMed2001

Inspiratory capacity, dynamic hyperinflation, breathlessness, and exercise performance during the 6-minute-walk test in chronic obstructive pulmonary disease.

Patients with severe chronic obstructive pulmonary disease (COPD) develop dynamic lung hyperinflation (DH) during symptom-limited incremental and constant work exercise with cycle ergometer and treadmill. The increase in end-expiratory lung volume seems to be the best predictor of dyspnea. Quantification of DH is based on the relatively complex use of on-line measurement of inspiratory capacity (IC) from flow volume loops. We reasoned that DH could occur during daily activities such as walking, and that it could be simply measured using the spirometrically determined IC. We studied 72 men with COPD (FEV(1) = 45 +/- 13.3% predicted). IC was measured at rest and after a 6-min walk test. Exertional dyspnea was evaluated using the Borg scale and dyspnea during daily activities with the modified Medical Research Council (MRC) scale. IC decreased significantly from 28.9 +/- 6.7% TLC at rest to 24.1 +/- 6.8% TLC after exercise (p < 0.001). Exertional dyspnea correlated with DeltaIC (r = -0.49, p < 0.00001) and baseline MRC (r = 0.59, p < 0.00001). In many patients with COPD, walking leads to DH that can be easily determined with simple spirometric testing. DH helps explain exercise capacity limitation and breathlessness during simple daily activities.

Activities of Daily Living↗

PubMed2001

An epidemiological study of Haemophilus influenzae at a Brazilian day care center.

Day care centers are a relatively new phenomenon in Brazil that bring together large numbers of young children susceptible to contagious diseases. Haemophilus influenzae (Hi) is an important infection in the age range of those attending day care centers. In the present study, the carriage rate of Haemophilus influenzae was identified in 38 day care attendees age 6 to 37 months, and 23 staff members, at a day care center in Ribeirão Preto-São Paulo, in 1997. To identify the carriers, two nasopharyngeal swabs were collected; one in July and one in December. The rate of H. influenzae carriers among the children was 77%. Only 2 of 23 staff members (9%) had Hi. Among the children, there were 58 isolates in the two sampling periods; 6 of the Hi were serotype b, 1 was serotype e, and 48 isolates were non-typeable. Two were identified as H. parainfluenzae. One adult had a non-typeable Hi and 1 had H. paraphrohaemolyticus. Three of the 6 children with type B had received a conjugate vaccine against H. influenzae type b, but they still carried this bacterium in the nasopharynx (50%). Forty ribotype patterns were found among the isolates, showing a high exchange rate of nontypeable H. influenzae carriers. The results indicate that, because of the high and changing biotype of Hi carriage, day care centers should be carefully monitored as potential point source of HI disease in the community.

Bacterial Capsules↗

PubMed1999

Ventilatory drive at rest and perception of exertional dyspnea in severe COPD.

BACKGROUND: The reasons for exertional dyspnea in severe COPD are not well established, but they are not solely related to the mechanical load. We tested the hypothesis that breathlessness may be determined, in part, by the response of an individual's central output. METHODS: In 26 patients with severe COPD (FEV1 < 50% predicted) and 22 matched control subjects, we assessed at rest the ventilatory and mouth occlusion pressure (P0.1) response to hyperoxic progressive hypercapnia. At rest and during a symptom-limited exercise test, routine cardiopulmonary variables were measured, and respiratory muscle function was evaluated using esophageal and gastric pressure. Dyspnea was assessed with a visual analog scale. RESULTS: Dyspnea with or without leg discomfort limited exercise in 73% of patients. Peak exercise dyspnea correlated only with dyspnea at rest (r = 0.5, p < 0.008) and P0.1 response to CO2 (deltaP0.1/delta[end-tidal PCO2]PETCO2) (r = 0.48, p = 0.02). Multiple regression analysis including resting and exercise data as independent variables revealed that 47% of the variance for dyspnea at peak exercise was explained by a model including dyspnea at rest and deltaP0.1/deltaPETCO2. Again, deltaP0.1/deltaPETCO2 was the only predictor for the change in dyspnea from rest to peak exercise (delta Dyspnea, r2 = 0.28, p = 0.005). There was no correlation between exercise dyspnea and any metabolic variable, pulmonary function, or respiratory muscle function test. CONCLUSION: In severe COPD, exertional dyspnea is not simply related to respiratory muscle load or mechanical impairment, but also to an individual's central motoneural output to the respiratory system.

Adult↗

PubMed1998

Obstructive sleep apnea and acute myocardial infarction: clinical implications of the association.

It is not known whether patients with acute myocardial infarction (MI) with coexistent obstructive sleep apnea (OSA) have a poor clinical course during the acute phase of MI. Therefore, we investigated the impact of OSA on in-hospital morbidity and mortality during an acute MI. Patients admitted to the intensive cardiac unit (ICU) with acute MI underwent Holter monitoring and night pulse oximetry (SpO2). During the first complete day at the ICU, both recordings (ECG and SpO2) were matched in time to determine association between cardiac arrhythmias and hypoxemia episodes. We identified and compared 55 heavy snorers with daytime sleepiness who showed more than 10 episodes of desaturation per hour on pulse oximetry (OSA group), and 196 nonOSA patients. There was an increase in the incidence of premature ventricular contraction (PVC, p < 0.05) and couplets PVC (p < 0.05) in OSA patients; the proportion of those arrhythmias increased in parallel with desaturation episodes in the OSA group. There were no differences between OSA and nonOSA groups for major MI complications (38.2% vs 34.2%, p > 0.05), ICU/hospital stay (3.6 +/- 1.2 vs 2.7 +/- 0.9 days, p > 0.05), or mortality within 30 days (14.5% vs 12.2%, p > 0.05). In conclusion, despite the greater incidence of some types of cardiac arrhythmias during an acute MI in OSA, these patients have the same clinical course in hospital and mortality rate as nonOSA patients.

Acute Disease↗

PubMed1997

Spontaneous disappearance of Elschnig pearls after neodymium:YAG laser posterior capsulotomy.

Posterior capsule opacification (PCO) from Elschnig pearl formation is a common complication of extracapsular cataract extraction. After PCO treatment by neodymium:YAG (Nd:YAG) laser posterior capsulotomy, Elschnig pearls may undergo hyperproliferation at the edge of the capsulotomy, which may close it. We have seen six eyes in five patients who presented with spontaneous disappearance of Elschnig pearls, resulting in a perfectly clear posterior capsule several years after an Nd:YAG posterior capsulotomy. Possible causes include (1) falling of pearls into the vitreous through the capsulotomy; (2) phagocytosis of pearls by macrophages; (3) cell death by apoptosis.

Aged↗

PubMed1997

Prevalence of sleep apnoea syndrome in the Spanish adult population.

BACKGROUND: Some data indicate that obstructive sleep apnoea syndrome (OSAS), a disorder characterized by recurrent episodes of cessation of respiratory airflow during sleep, is highly prevalent in the general population but no such data exist in southern Europe. METHODS: In the Zaragoza metropolitan area (northeast of Spain) a representative sample of 1360 subjects aged > 18 years and selected by quota methods according to age, sex and geographical distribution agreed to participate. Trained interviewers visited selected residents to administer a sleep questionnaire in the presence of a bedmate or another closely-related person who lived in the subject's home; anthropometric data and arterial blood pressure were also recorded. All participants were invited to record nocturnal home oximetry (NHO). The NHO results were classified as 'abnormal' (or consistent with OSAS) in the presence of repetitive, short-duration arterial oxyhaemoglobin saturation (SaO2) fluctuations. RESULTS: The diagnosis of OSAS was established in subjects with loud (severe) snoring + excessive daytime sleepiness + abnormal oximetry In the group of 1222 subjects (597 males, 625 females) who agreed to have NHO, 63.7% of men and 36.3% of women snored 'usually' or 'always' (severe snorers): daytime sleepiness in active situations occurred in 12.1% and 14.4% respectively. The association of severe snoring plus daytime sleepiness plus abnormal NHO was found in 18 subjects (13 males, 5 females). CONCLUSIONS: We estimated that among Spanish adults, 0.8% of women and 2.2% of men meet the minimal criteria to diagnose sleep apnoea syndrome.

Adolescent↗

PubMed1996

Effects of nedocromil sodium in steroid-resistant asthma: a randomized controlled trial.

BACKGROUND: Some patients with asthma respond poorly to corticosteroids and have persistent airway inflammation and daily clinical symptoms. The aim of this study was to investigate the effects of nedocromil sodium (NS), a nonsteroidal antinflamatory drug, in the treatment of steroid-resistant asthma. METHODS: Steroid-resistant asthma as diagnosed in any patient who demonstrated 20% improvement in FEV1 after treatment with inhaled salbutamol with failure of FEV1 to improve by at least 15% after a 2-week trial of prednisolone, 30 mg daily. In a double-blind placebo-controlled trial, the patients received either 4 mg of inhaled NS (n = 13) or placebo (n = 13), 4 times daily for 3 months. RESULTS: NS but not placebo resulted in a mean increase in FEV1 of 11.4% after 12 weeks of therapy (p = 0.05) and of 12.4% (p = 0.04) and 15% (0.02) in morning peak expiratory flow after 8 and 12 weeks of treatment, respectively. Changes in FEV1 at 4 and 8 weeks and in peak expiratory flow at 4 weeks of NS therapy were not significant. NS was also effective in reducing variability of peak expiratory flow (p = 0.02) and use of salbutamol (p = 0.005) and in improving quality of life (p = 0.007) by the trial end. Six of the 12 patients treated with NS who completed the treatment period showed a "good response," defined by a reduction in salbutamol use of more than 50% and an increase in morning peak expiratory flow of more than 20% from baseline; there were no clinical predictors of this response. Two patients were withdrawn from the study because of severe asthma exacerbation (one from each treatment group). CONCLUSION: Inhaled NS improved pulmonary function and decreased asthma severity in steroid-resistant asthma, but its effectiveness is not homogeneous and cannot be predicted from baseline clinical data.

Adult↗

PubMed1994

Changes in obstructive sleep apnea characteristics through the night.

It was our impression that the respiratory parameters in obstructive sleep apnea (OSA) worsened as the night progressed. To confirm this, we review polysomnographic studies from 66 patients with apnea-hypopnea indices (AHI) of 40 to 125 events per hour, dividing bed time into equal quartiles. As the night progressed, the mean apnea duration (MAD) increased from 27.2 s to 34.6 s (p < 0.0001), mainly from increases during NREM sleep. The proportion of time spent in apnea increased from 54 to 71% (p < 0.0001) due to increases in both MAD and the proportion of REM sleep (from 2.8 to 14.7% of the total sleep time). The AHI did not change significantly between quartiles. Even though preapneic oxygen saturation did not change and apnea duration increased as the night progressed, the end-apneic saturation did not decrease, hence the rate of oxygen desaturation decreased. Also, it was found that patients with an AHI greater than 65 events per hour increased their proportion of time spent in apnea significantly more than those with an AHI smaller than 65, as the night progressed. In the patients with an AHI greater than 85, this was due to both an increase in MAD and AHI. In conclusion, in patients with an AHI greater than 40 events per hour, the severity of apnea increased as the night progressed due to lengthening of MAD, increased proportion of REM sleep, and in the most severe patients, also an increase in AHI. Even though the exact pathophysiologic mechanisms for the observed changes are unknown, a decrease in respiratory muscle effort with consequent decrease in oxygen consumption may explain both the lengthening of the apneas and the decrease in the rate of oxygen desaturation.

Apnea↗

PubMed1993

Influence of the climacteric on the bone mass of the spine and femur.

OBJECTIVE: To determine the correlation between the bone mass of the lumbar spine and the neck of the femur in Spanish climacteric women. METHOD: Bone mass was measured using quantitative digital radiology in 200 climacteric women who had no record of receiving hormone replacement therapy. RESULT: A statistically significant correlation (P < 0.05) is observed between the bone mineral density and content of the lumbar spine and the femur in all the groups of climacteric women, although only in the postmenopausal women does it approach 70%. A direct relationship is observed between the loss of bone mass and the onset of the menopause, as well as with the patients' body mass index. CONCLUSION: When the different parameters are analyzed, the results show that measurement of the lumbar spine is essential, and measurement of the femur should not be used as a substitute, but rather in addition to it.

Adult↗

PubMed1993

Relationship of resting lung mechanics and exercise pattern of breathing in patients with chronic obstructive lung disease.

To investigate the influence of resting pulmonary mechanics on the pattern of breathing during exercise in chronic obstructive pulmonary disease (COPD), we studied 29 patients with moderate to severe COPD (FEV1 50 +/- 20 percent predicted), and 10 normal subjects. Lung mechanics were studied using esophageal balloon technique and body-box. Incremental exercise testing was performed to exhaustion. As minute ventilation (VE) increases, COPD patients with the highest pulmonary resistance (RI) or lowest elastic recoil pressure (PL), used a greater tidal volume/vital capacity ratio (VT/VC) than the COPD patients with more normal RL or lowest PL. To describe the breathing pattern during exercise, an exponential constant (K) describes the rates of increase in VT/VC ratio with increasing VE, calculated according to the equation VT = VC(1-e-KVE). The K values achieved by COPD patients were higher than in normal subjects. In addition, K value correlated negatively with the resting FEV1 and FVC of COPD patients. When COPD patients were grouped according to their K values, it was revealed that patients with high K values generated greater VT/VC ratio and also have the most abnormal resting lung mechanics. These results suggest that the exercise breathing pattern in COPD patients is significantly influenced by the degree of impairment of resting lung mechanics.

Adult↗

PubMed1991

Subclinical cardiac dysfunction in sarcoidosis.

Clinically apparent myocardial disease is infrequent in sarcoidosis. However, autopsy data show myocardial involvement in up to 30 percent of patients. Unexplained exertional symptomatology is a common complaint in patients with sarcoidosis. In this study, we investigated whether abnormal cardiac function might limit exercise performance in patients with sarcoidosis without overt cardiac involvement. We studied exercise responses in 35 patients with sarcoidosis and compared them with 28 untrained controls. Seventy-seven percent of the patients were symptomatic. Pulmonary function test results were lower in the group with sarcoidosis than normal controls, but they were within normal range. Only one patient had evidence of ventilatory limitation to exercise. Sixteen (46 percent) patients had abnormally increased heart rates (HRs) at rest prior to exercise testing and/or with exercise. Rapid HRs were confirmed during daily activities by continuous ambulatory electrocardiographic (ECG) monitoring. Left ventricular ejection fraction (LVEF) was measured to determine if systolic dysfunction could account for abnormal HR responses. Of patients with abnormally increased HRs, five had LVEFs less than 50 percent, and eight had normal LVEFs, of whom 75 percent had tachycardia at rest. Retrospective comparison of HR responses and LVEF between patients who did or did not receive corticosteroids revealed no significant differences between groups. We conclude that abnormal HR responses in patients without evident cardiac sarcoidosis are common and exertional symptoms in this population are often associated with chronotropic abnormalities. The exact mechanisms underlying the chronotropic abnormalities are unclear, but they likely include ventricular systolic dysfunction, sinus node dysfunction from granulomatous infiltration, or combinations of the two.

Adult↗

PubMedDate not supplied

Prevalence of mutans streptococci in 93 members from six Brazilian families.

Several studies report that mutans streptococci (MS) are closely associated with caries in humans and that there is a correlation between the number of carious lesions and the levels of MS in the saliva of children and adults. The presence of MS in the saliva of 93 members of six Brazilian families with at least 3 generations was investigated. Samples of whole unstimulated saliva were collected and diluted. Aliquots of 50 microliters of each suspension were dropped onto SB20 agar and incubated in a candle jar at 37 degrees C for 72 h. Colonies resembling MS were counted, collected, seeded in thioglycoilate medium and subjected to biochemical typing. Mutans streptococci were isolated from 80 subjects (86.0%) and the counts ranged from 3.0 x 10(2) (log 2.477) to 1.6 x 10(8) (log 8.204) CFU/ml of saliva. All of the 73 adults were colonized by MS, but the bacteria were detected in only 7 (35.0%) of the 20 children evaluated. Streptococcus mutans occurred in 78 subjects (97.5%), and 51 (63.7%) were monocolonized. S. sobrinus occurred in 29 individuals (36.3%) and 2 (2.5%) were monocolonized. Twenty-seven (33.8%) subjects were multicolonized with S. mutans and S. sobrinus. This study showed a high prevalence (86.0%) of mutans streptococci in the saliva of members of the studied families, which suggests the risk of intrafamilial transmission.

Adult↗