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Biomedical subjects

J Serra

Publications and source records attributed to J Serra.

At least 55 records · Page 3Linked to original sources
PubMed1999

[The metabolic-chronotropic relation in patients with heart failure--a correlation with functional capacity].

UNLABELLED: Previous studies on chronotropic incompetence (CI) in patients with congestive heart failure (CHF) have defined it as the inability to achieve > 80% of age predicted maximum heart rate (HR) (adequacy of HR response to submaximal exercise levels not being considered). The metabolic chronotropic relation (MCR) concept proposed by Wilkoff allows the assessment of the entire chronotropic function. The value of such an approach for the evaluation of CI in patients with CHF, and its relation to exercise capacity, is unclear at present. METHODS: We imposed maximal symptom-limited treadmill exercise testing while measuring breath-by-breath oxygen consumption, using CAEP protocol, in 25 patients (19 men), 49 +/- 10 years, all in sinus rhythm, with CHF secondary to dilated cardiomyopathy (17) or ischemic heart disease (8), NYHA class II-III. Anaerobic threshold (AT) was attained by all. No exercise was terminated due to arrhythmia or ischemia. MCR was calculated as the slope of the relation between the percentages of HR and metabolic reserves achieved at the end of each exercise stage. Using 2.0 standard deviations below the mean level of MCR in healthy controls, we defined an MCR value < 0.84 as abnormal. The parameters analysed were: age, drug therapy, fractional shortening (FS-%), resting HR (RHR-bpm), exercise duration (DUR-min), peak HR (HRp), peak oxygen consumption (VO2p-ml/kg/min), percentages of predicted maximal HR (% PMHR) and VO2 (% PMVO2), peak ventilatory equivalent for CO2 (VE/VCO2-L/min), time to AT (T-AT), and VO2 at AT (VO2-AT). RESULTS: MCR was normal (1.01 +/- 0.18-0.86 to 1.19) in 10 patients--Group I, and abnormal (0.66 +/- 0.13-0.42 to 0.81) in 15 (60%) patients--Group II. A similar proportion of patients in both groups were taking ACE inhibitors, digoxin and amiodarone. [table: see text] CI defined as an inability to achieve a % PMHR > 80% occurred only in 6 (24%) patients, all in Group 2 (p = 0.022 versus abnormal MCR). CONCLUSIONS: In CHF patients, CI assessed as an abnormal MCR is frequent, and relates to an impaired exercise capacity.

Adult↗
PubMed1998

[Prognostic factors and etiology in patients with severe community-acquired pneumonia admitted at the ICU. Spanish multicenter study. Study Group on Severe Community-Acquired Pneumonia in Spain].

OBJECTIVE: To determine the techniques used for the etiological diagnosis of community-acquired pneumonia in patients admitted to the intensive care unit (ICU) and to describe the predominant causative organisms as well as prognostic factors of ICU mortality. PATIENTS AND METHODS: A total of 262 patients with community-acquired pneumonia admitted to 26 ICUs between 1 November of 1991 and 31 October of 1992 were included in a prospective, open, multicenter study. RESULTS: The diagnostic techniques most frequently used were blood culture (243 cases) and simple tracheal aspirate (166 cases). Simple tracheal aspirate (58.4%), bronchoalveolar lavage (47.7%), and protected-specimen brush (44.2%) were the techniques that showed the highest diagnostic reliability. In 220 cases, techniques considered of high diagnostic probability were employed. With the use of these procedures, the most frequent causative pathogens were Streptococcus pneumoniae (13.6%) and Legionella pneumophila (9.5%). In 100 cases (45.5%), no pathogen was isolated. A total of 88 patients (33.6%) died during the ICU stay. Predictive variables of poor outcome selected by means of a multivariate analysis were as follows: multisystemic failure (OR = 28.6; 95% CI: 12.8-65.1; p = 0.0001), APACHE II at the time of ICU admission (OR = 5.3; 95% CI: 2.5-11.3; p = 0.0001), progression and/or spread of lung infection (OR = 4.5; 95% CI: 2.4-8.4; p = 0.0001), and shock on admission (OR = 8.48; 95% CI: 4.5-15.9; p = 0.0001). CONCLUSIONS: In 45.5% of patients with community-acquired pneumonia admitted to ICU, no causative pathogen was identified. The prognosis of these patients was influenced by the severity of disease assessed by APACHE II score and presence of multisystemic failure and shock at the time of ICU admission.

Community-Acquired Infections↗
PubMed1998

Modulation of gut perception in humans by spatial summation phenomena.

1. We have recently shown that perception of intestinal stimuli increases by spatial summation phenomena. Our aim was to determine in humans whether intestinal perception depends on (a) the length of gut stimulated, and (b) the distance between stimuli. 2. In a first series of studies, we compared perception of isobaric intestinal distensions applied over a 3 cm segment and a 36 cm segment by means of two separate barostats (n = 8). In a second series of studies we compared perception of intestinal distensions applied simultaneously by two balloons sited 3, 12 or 48 cm apart (n = 6). 3. Distension of the 36 cm segment induced significantly greater perception than distension of the 3 cm intestinal segment (discomfort perceived at 20 +/- 2 mmHg and 31 +/- 2 mmHg, respectively; P < 0.05). Perception of intestinal balloon distension increased when a second stimulus was simultaneously applied, independently of the distance between the two balloons (the discomfort thresholds were 30 +/- 11, 20 +/- 6 and 28 +/- 7% lower with simultaneous distensions 3, 12 and 48 cm apart, respectively). 4. We conclude that perception of intestinal distension is determined by the extension of the field of stimulation, and the summation effect is similar whether adjacent or distant fields are stimulated.

Adult↗
PubMed1998

Ectopic impulse generation and autoexcitation in single myelinated afferent fibers in patients with peripheral neuropathy and positive sensory symptoms.

Microneurographic studies were performed using cutaneous nerves of 8 patients with documented peripheral neuropathy who expressed positive sensory symptoms. Intraneural recordings in single myelinated fibers revealed: (i) ectopic generation of bursts of spontaneous action potentials; (ii) ectopic generation of ongoing repetitive discharges transiently interrupted by natural stimulation of the receptive field; and (iii) repetitive discharges triggered by a preceding action potential. These results provide direct evidence of a peripheral pathophysiological basis for spontaneous and stimulus-induced paresthesias and dysesthesias in patients with peripheral neuropathy.

Action Potentials↗
PubMed1998

Efficacy of PdB in preventing intraoperative risk of infectious diseases.

The objectives of this study were to (1) determine the number of punctures surgeons and assistants suffer during operations involving a laparotomy during the intraabdominal and closure phases; and (2) determine if the number of puncture injuries during wound closure can be reduced using a new surgical instrument (PdB) that protects the surgeon's hands and the patient's viscera against needlesticks. For the first objective, all laparotomies performed during 1 month (n = 52) were controlled, collecting the gloves used and determining the number of perforations. For the second objective, a randomized prospective controlled study, involving two series of 100 medial laparotomies, was carried out. The incidence of perforations was 29% during the intraabdominal phase and 16% during the wound closure phase. The glove perforation rate while closing medial laparotomies was 31.5% if the PdB was not used and 3% if the PdB was used (p < 0.0001). The glove perforation rate during laparotomy is significant, but with the use of the PdB this incidence can be significantly reduced.

Abdominal Muscles↗
PubMed1998

Intestinal gas dynamics and tolerance in humans.

BACKGROUND & AIMS: Abdominal symptoms are often attributed to intestinal gas. In humans, gas production and composition have been previously investigated, but intestinal gas dynamics and tolerance remain virtually unknown. The aim of this study was to establish the relationship between intestinal gas loads, evacuation, perception of symptoms, and objective abdominal distention in healthy humans. METHODS: A dose-response study was performed in 46 healthy subjects; intestinal gas was infused for 3 hours (0, 1, 4, 12, and 30 mL/min), and anal gas evacuation, symptom perception, and abdominal distention were measured. A mixture of gases was infused in venous proportions to minimize diffusion. Anal gas recovery and calculations of gas retention were validated using sulfur hexafluoride as a nonabsorbable gaseous marker. RESULTS: At all of the infusion rates, gas evacuation rapidly equilibrated and paralleled gas infusion without significant differences in perception. Only 6 subjects retained >400 mL gas, and 5 of them developed abdominal distention and symptoms. By contrast, all but 4 of the 41 subjects without retention tolerated the gas loads without discomfort. CONCLUSIONS: Intestinal gas tolerance is normally high, because expeditious gas transit and evacuation prevent gas pooling and symptoms. When this protective mechanism is insufficient, gas retention occurs, and it causes abdominal symptoms and distention.

Abdomen↗
PubMed1998

Intercontinental spread of a multidrug-resistant methicillin-resistant Staphylococcus aureus clone.

Two hundred ten methicillin-resistant Staphylococcus aureus (MRSA) isolates recovered between 1990 and 1997 from three Portuguese hospitals located in Lisbon and Oporto were analyzed by molecular fingerprinting techniques. The hybridization of ClaI restriction digests with the mecA- and Tn554-specific DNA probes combined with pulsed-field gel electrophoresis documented the abrupt appearance and extensive intrahospital spread of the Brazilian epidemic MRSA clone in the 1995 samples of each one of the three hospitals analyzed-suggesting the intercontinental transfer of this strain from Brazil to Portugal. The appearance of this clone may challenge the dominance of another highly epidemic imported clone-the Iberian MRSA, currently the most widely spread MRSA clone in Portuguese hospitals.

Brazil↗
PubMed1998

Flare and hyperalgesia after intradermal capsaicin injection in human skin.

Flare and hyperalgesia after intradermal capsaicin injection in human skin. J. Neurophysiol. 80: 2801-2810, 1998. We investigated the neurovascular mechanisms that determine the flare response to intradermal capsaicin injection in humans and delineated the associated areas of mechanical and heat hyperalgesia. The flare response was monitored both visually and with infrared telethermography. The areas of mechanical and heat hyperalgesia were determined psychophysically. Thermography detected very large areas of flare. As an early event underlying the flare and before onset of the area of rubor of the skin, thermography detected the appearance of multifocal spots of increased temperature caused by dilatation of cutaneous arterioles. Repetition of capsaicin injection days apart into the same forearm induced multifocal spots of temperature elevation identical to the ones obtained in the first session, indicating dilatation of the same arterioles. Reactive hyperemia also consisted in the appearance of multifocal spots of increased temperature, which were identical to the ones reacting during the flare response, suggesting participation of the same arterioles in both events. Strips of local anesthetic placed to block cutaneous nerves prevented the spread of both the thermographic flare and associated hyperalgesia. It is inferred that the cutaneous nerve fibers responsible for the thermographic flare branch, or have coupled axons, over a long distance. The large area of flare coincided with the area of mechanical and heat hyperalgesia. Equivalence of the areas of flare and mechanical and heat hyperalgesia induced by intradermal capsaicin injection suggests that all three phenomena are the consequence of neural factors that operate peripherally.

Adult↗
PubMed1998

Helical CT versus CT arterial portography in the detection of hepatic metastasis of colorectal carcinoma.

OBJECTIVE: The study is a prospective comparison of helical CT with nonhelical CT arterial portography (CTAP) in the detection of liver metastases from colorectal carcinoma, using surgical and histologic findings as the gold standard. SUBJECTS AND METHODS: Thirty-five patients with colorectal carcinoma and suspected liver metastases were prospectively examined with helical CT and CTAP before surgery. In nine cases, surgery was not performed. In the remaining 26 patients, imaging results were correlated with surgical and pathologic findings. Three radiologists prospectively assessed metastatic involvement with both techniques. The results were compared with pathologic and surgical findings on a lesion-by-lesion basis. In a second phase, three radiologists not directly concerned in the design of the study independently assessed metastatic involvement of the liver as revealed on helical CT and CTAP on a segment-by-segment basis with a five-level scale of confidence. Results were analyzed by receiver operating characteristic methods. RESULTS: The results of the histologic study disclosed 50 metastatic lesions. Helical CT had a sensitivity of 76% (38/50) and a positive predictive value of 90%. CTAP had a sensitivity of 74% (37/50) and positive predictive value of 69%. Receiver operating characteristic analysis revealed a greater area under the curve (Az index), 0.96, for helical CT than for CTAP (0.86). Differences were statistically significant (p < .001). CONCLUSION: Helical CT is superior to nonhelical CTAP in the detection of hepatic metastases from colorectal carcinoma.

Adult↗
PubMed1998

[Omeprazole: a new treatment for paranasal sinus polyps in Widal syndrome. Preliminary study].

A preliminary report is made of the potential therapeutic effect of omeprazol in reducing nasosinusal polyps. This study is based on the empirical observation of nasal airflow improvement in patients suffering from nasosinusal polyposis after administering omeprazol. Different phases of the study suggested that patients with Widal's syndrome benefited the most. Based on the results of this study, we have undertaken a randomized, parallel, double-blind, placebo-controlled clinical trial.

Anti-Inflammatory Agents↗
PubMed1998

[Audit of deaths due to cervical cancer in a health service of Santiago. A preliminary analysis].

BACKGROUND: Despite the epidemiological importance and the surveillance programs to detect cervix uterine cancer in Chile, its mortality continues to be high. AIM: To perform an audit of all deaths due to cervix uterine cancer, that occurred in a health service of Santiago during 1995. MATERIAL AND METHODS: The clinical records and pathological studies of 46 women, whose death certificates indicated cervix uterine cancer as the cause of death, were audited. RESULTS: In six women, the audit revealed that the cause of death was not a cervix uterine cancer, and they were discarded from further analyses. The higher mortality rate (36/100,000) occurred in women over 64 years old, those living in the poorest community and with less Papanicolaou vaginal smears coverage (La Pintana). The evolution prior to diagnosis was registered in only four women and was of less than one year. Most women consulted in advanced stages of the disease and only 48% were subjected to some sort of treatment (surgery, radiotherapy or chemotherapy). Mean survival was 3 years and mean age at death was 55.5 years old. There was a great lack of clinical and epidemiological information. In only 13 women information about previous Pap smears was registered. CONCLUSIONS: Audit of deaths should be an important component of preventive programs for cervix uterine cancer, and the coverage of Pap smears should be improved.

Adult↗
PubMed1998

[Nitric oxide synthase activity in nasal mucosa].

Nitric oxide (NO) plays an important regulatory role in airway function and seems to be implicated in the pathophysiology of several airway diseases. We studied the presence of NO synthase activity in human nasal mucosa and nasal polyp tissues obtained from patients undergoing septoplasty or polypectomy, respectively. NO synthase activity was quantified in tissue homogenates using citrulline release assay and was located in tissue sections using NADPH-diaphorase histochemistry. The results indicated that nasal polyps contain higher levels of total NO synthase activity than nasal mucosa tissue. In addition, nasal polyps contained mainly inducible NO synthase activity whereas all NO synthase activity detected in the nasal mucosa was in constitutive form. In both cases, NO synthase activity was localized in epithelial cells. In view of these results, we conclude that NO may be an important inflammatory mediator in the respiratory system and that the epithelium may be a source of NO production.

Adult↗
PubMed1998

[Second primary tumors in patients with laryngeal neoplasms].

A cohort epidemiologic study of second primary tumours appeared in patients diagnosed of laryngeal neoplasms, between years 1988 and 1990, and a follow-up term of 5 years, is presented. An statistical analysis of several data to define a possible high risk group for developing primary tumours was performed for all patients.

Adolescent↗
PubMed1997

[Single dose of fleroxacin for the treatment of adult acute diarrhea].

The purpose of this work was to evaluate the efficacy and safety of a single dose of 400 mg of fleroxacin for the empiric antibiotic treatment of acute diarrhea in adult patients. A prospective, double-blind, placebo-controlled, randomized trial was designed. All the adult patients who consulted in our hospital for acute diarrhea from December 1994 to April 1995 were included. 72 patients were randomized to receive a single dose of fleroxacin 400 mg and 73 were placebo. Thirty-eight patients in each group were evaluable for efficacy. Between both groups there were not statistically significant differences in age, sex, number of loose stools per day at inclusion, days since the onset of symptoms up to inclusion, other symptoms than diarrhea at inclusion, percentages of bacterial pathogens and parasites isolated and symptomatic treatment indicated. At the third day since inclusion, clinical cure occurred in 72.2% of the patients receiving fleroxacin, compared with 36.4% of those receiving placebo; p = 0.002. The mean +/- SD time to cure was 2.2 +/- 1.2 days in the fleroxacin group and 3.2 +/- 2.0 days in the placebo group; p = 0.01. Twenty-eight and 16.7% of patients reported adverse effects in the fleroxacin and placebo groups respectively; p = 0.3. It is concluded that a single dose of fleroxacin 400 mg is an effective and safe alternative for the empiric antibiotic treatment of acute diarrhea in adults.

Acute Disease↗
PubMed1997

[Postoperative infections in critically ill patients].

Patients subjected to surgery often develop nosocomial infections, among which the intra-abdominal ones stand out as being a common cause of septicemia, multi-organ failure, and death of the critical patients. Advances have been made in the study of the physiopathology by studying the mediators which are responsible for the systemic inflammatory response, the microbiology (changes in the pathogen type and in the antimicrobial sensitivity), and for the clinical picture (cholecystitis, tertiary peritonitis). Abdominal ultra-sound and computerized axial tomography have contributed greatly to the diagnosis of these infections. The new treatment techniques are discussed, both of the drainage of the septic focus (percutaneous or surgical), as of the antimicrobial treatment and the supportive measures. The diagnostic and therapeutic advances have modified the prognosis of these patients, although this continues to be poor when there is development of the multi-organ failure syndrome.

Bacterial Infections↗
PubMed1997

[Microbiological and auditory analysis before and after topical treatment of chronic suppurative otitis media without cholesteatoma].

The AA. present a study microbiologic and auditive as well about chronic, suppurative otitis media non cholesteatomatous, before and after topical treatment. They contemplate 178 samples of chronic discharging ears which were treated with gentamycin 0.3 %, instillation 5 drops every 8 hours, during 10 days. Twelve days later were newly assessed both the otorrhea and the cochleovestibular picture. Germs most frequently detected: Gram-negative 61.6 %, Gram-positive 19.8 %, associated flora 6.4 % and mycosis 2.2 %, among other. Clinic healing accounted for 97.29 % and not significative differences scored pre--and post-treatment.

Administration, Topical↗
PubMed1996

C-polymodal nociceptors activated by noxious low temperature in human skin.

1. Fifty-five C-polymodal nociceptors innervating hairy skin in human volunteers were tested for discrete stimulus-response properties through microneurography. 2. All fifty-five units were responsive to mechanical and heat stimuli. Twenty-two (40%) of these exhibited an additional response to noxious low temperature. The twenty-two mechano-heat-cold nociceptors displayed similar receptor responses to heat and mechanical stimuli, and conduction velocity, as those of the pure mechano-heat C-polymodal nociceptors. 3. Low temperature stimuli between 19 and 0 degree C evoked responses at low discharge frequency (0.4 +/- 0.22 impulses s-1, mean +/- S.E.M.) in the twenty-two units sensitive to such energy. These units displayed a tendency to decrease their discharge after a few seconds of steady stimulation. 4. Three units tested with a freezing stimulus responded with relatively vigorous discharge, which never exceeded the maximal discharge frequency elicited by either mechanical or heat stimuli. One of these units became sensitized to heat after the freezing challenge. 5. It is concluded that a subpopulation of C-polymodal nociceptors is sensitive to noxious low temperature and may thus contribute to the determination of cold pain. The same type of primary afferent is probably one mediator of the symptom cold hyperalgesia in peripheral nerve disease.

Action Potentials↗