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Biomedical subjects

J Gea

Publications and source records attributed to J Gea.

At least 19 recordsLinked to original sources
PubMed1997

Diaphragm muscle fiber injury after inspiratory resistive breathing.

Five awake previously tracheotomized mongrel dogs were challenged with inspiratory resistive breathing (IRB). The mean peak tracheal pressure = -35.4 +/- 1.1 cmH2O, ETCO2 = 39.8 +/- 1.5 mmHg was sustained for 2 h/d over 4 consecutive d. On the fourth day, following IRB, the dogs were placed under general anaesthesia, and the diaphragm was perfused via the internal mammary artery with a low molecular weight fluorescent tracer (Procion orange, FW = 631), to which normal muscle fibers are impermeable. Muscle fiber membrane damage was identified on tissue sections by using fluorescent microscopy showing the presence of the tracer in the cytoplasm. Four dogs undergoing the same protocol (except IRB) served as control. The dye was seen in 7.6 +/- 2.6% and in 0.3 +/- 0.1% of fibers in the IRB and control groups, respectively (p < 0.05). Via ATPase staining, it was found that fibers of type I were predominantly affected as compared to type II (p < 0.05). In addition, an increased area fraction of fibers demonstrating sarcomere disruption was found after IRB (2.4 +/- 0.5%) compared to pre-IRB (0.4 +/- 0.1%; p < 0.05). We conclude that resistive breathing of a magnitude similar to that seen in some respiratory diseases, or used in respiratory muscle training programs induces muscle membrane and sarcomere injury.

Animals↗
PubMed1995

[Muscle relaxants in the morphometric study of the respiratory muscles in human beings].

The morphological examination of respiratory muscle can be affected by muscular contraction following biopsy. Most morphometric studies of respiratory muscles, however, have been carried out without taking into account this factor, the effect of which can be reduced by using relaxants when taking samples. Objective. To examine the effect of using a relaxant in the morphometric analysis of muscle fibers. We examined 31 muscle samples from 7 patients. Immediately after removal, each pipe was divided in half. One was placed in an isotonic physiological solution and the other in a solution of curare 0.02%. Later, both samples were processed for morphometric study with ATP-ase, NADTH and PAS tincture. Morphological data recorded for the different types of fibers included measurement of minimum diameter (Dmin), atrophy and hypertrophy indices (AI and HI) and heterogeneity of distribution (SDDmin). The Dmin was smaller in fibers transported in a curare solution than in those transported in physiological solution (67 +/- 2 microns vs. 71 +/- microns, p < 0.05). The same was true of SDDmin (13 +/- 3 vs. 12 +/- 3, p < 0.05), HI (300 +/- 88 vs. 457 +/- 107, p < 0.05). Likewise, we found a similar direct correlation between size of fibers processed with physiological solution and those processed in curare (Dmin, r = 0.731, p < 0.001; HI, r = 0.827, p < 0.001; SDDmin, r = 0.636, p < 0.0001). The use of relaxants in processing muscle samples prevents contraction and should be used systematically in the morphological analysis of muscle fibers.(ABSTRACT TRUNCATED AT 250 WORDS)

Biopsy↗
PubMed1995

Effects of interpleural bupivacaine on respiratory muscle strength and pulmonary function.

BACKGROUND: Several reports suggest that interpleural local anesthetics may have deleterious effects on respiratory function. The current study investigated the effects of interpleural bupivacaine on human respiratory muscles and lung function. METHODS: Thirteen patients (55 +/- 4 yr old) with normal respiratory function and scheduled for cholecystectomy entered the study before surgery. Respiratory parameters were compared before and after the interpleural administration of 20 ml 0.5% bupivacaine plus 1:200,000 epinephrine while patients were supine; we evaluated breathing pattern, dynamic and static lung volumes, airway conductance, maximal inspiratory pressures (at the mouth; at the esophagus [Pessniff]; at the abdomen [Pgasniff]; and transdiaphragmatic [Pdisniff]), functional reserve (tension-time index) of the diaphragm, and maximal expiratory pressures (at the mouth; at the esophagus [Pescough]; and at the abdomen [Pgacough]). Hemoglobin oxygen saturation by pulse oximetry, heart rate, and mean arterial pressure were continuously monitored. RESULTS: Respiratory rate (15 +/- 1 to 19 +/- 1 breaths/min; P < 0.01) and heart rate (78 +/- 3 to 83 +/- 3 beats/min; P < 0.01) were slightly increased. Dynamic and static lung volumes, airway conductance, hemoglobin saturation, and the remaining breathing pattern parameters were unchanged. Regarding respiratory muscles, maximal inspiratory pressure at the mouth, Pessniff, and tension-time index of the diaphragm did not change. Pdisniff decreased slightly (102 +/- 10 to 92 +/- 10 cmH2O; P < 0.05) because of a change in Pgasniff (24.2 +/- 7.4 to 18.4 +/- 6.8 cmH2O; P < 0.05). Maximal expiratory pressure at the mouth remained unaltered, but Pgacough decreased (108 +/- 10 to 92 +/- 8 cmH2O; P < 0.01), and Pescough showed a trend to decrease (92 +/- 13 to 78 +/- 10 cmH2O; P = 0.074). CONCLUSIONS: In our experimental conditions, interpleural bupivacaine did not significantly change lung function or inspiratory muscle strength but induced a slight decrease in abdominal muscle strength. Although this effect was minimal, its clinical relevance needs to be evaluated further in patients with impaired respiratory function.

Adult↗
PubMed1995

Structure of the latissimus dorsi muscle and respiratory function.

The aim of this study was to evaluate whether respiratory function influences the structure of the latissimus dorsi muscle (LD). Twelve patients (58 +/- 10 yr) undergoing thoracotomy were studied. Lung and respiratory muscle function were evaluated before surgery. Patients showed a forced expired volume in 1 s (FEV1) of 67 +/- 16% of the reference value, an FEV1-forced vital capacity ratio of 69 +/- 9%, a maximal inspiratory pressure of 101 +/- 21% of the reference value, and a tension-time index of the diaphragm (TTdi) of 0.04 +/- 0.02. When patients were exposed to 8% CO2 breathing, TTdi increased to 0.06 +/- 0.03 (P < 0.05). The structural analysis of LD showed that 51 +/- 5% of the fibers were type I. The diameter was 56 +/- 9 microns for type I fibers and 61 +/- 9 microns for type II fibers, whereas the hypertrophy factor was 87 +/- 94 and 172 +/- 208 for type I and II fibers, respectively. Interestingly, the histogram distribution of the LD fibers was unimodal in two of the three individuals with normal lung function and bimodal (additional mode of hypertrophic fibers) in seven of the nine patients with chronic obstructive pulmonary disease. An inverse relationship was found between the %FEV1-forced vital capacity ratio and both the diameter of the fibers (type I: r = -0.773, P < 0.005; type II: r = -0.590, P < 0.05) and the hypertrophy factors (type I: r = -0.647, P < 0.05; type II: r = -0.575, P = 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1995

Activity of latissimus dorsi muscle during inspiratory threshold loads.

The ability of the latissimus dorsi muscle (LD) to participate as an accessory inspiratory muscle has been the subject of controversy. Electromyographic (EGM) activity of LD was evaluated in 11 healthy subjects (aged 30 +/- 2 yrs; forced expiratory volume in one second (FEV1) 106 +/- 5% predicted; maximal inspiratory pressure (Pmax), 120 +/- 6 cmH2O) under different breathing conditions. The ipsilateral biceps brachii was chosen as the control muscle. The EMG was recorded from surface electrodes, but needle electrodes were also used for LD evaluation in a subset of three subjects. The EMG signal from both muscles was recorded simultaneously, rectified and integrated, with subtraction of the electrocardiographic signal. Situations evaluated were: 1) maximal voluntary contraction (MVC); 2) apnoea; and 3) breathing under progressive inspiratory threshold loads (20-100% Pmax, at 20% intervals). A close relationship was evident between LD recordings from surface and needle electrodes (r = 0.975). Activity of LD at baseline was 1.8 +/- 0.4% MVC, and showed a phasic increase during inspiration under loads. This change had a linear tendency and was significant for loads corresponding to 40, 60, 80 and 100% of Pmax when compared to the control muscle. At this latter level, LD activity was equivalent to 32 +/- 5% MVC (range 11-61%), whereas mean activity of the control muscle was less than 7.5% MVC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Usefulness of respiratory endoscopy in patients with severe rhonchi and/or sleep apnea syndrome].

BACKGROUND: Obstruction of the upper respiratory tract is the most common cause of the sleep apnea syndrome (SAS). Different methods have been used to localize this obstruction and give the appropriate treatment. The aim of this study was to evaluate the usefulness of respiratory endoscopy performed during arousal to identify the site and cause of the obstruction in patients with severe rhoncopathy and/or SAS. METHODS: Sixty-eight patients with acute rhoncopathy were included in the study with 36 also fulfilling polysomnographic criteria of SAS (36%). The endoscopy was performed via the upper respiratory tract with inspiratory collapse at each level being evaluated in both easy respiration and during the Müller manoeuver. RESULTS: The site and cause of the obstruction was identified in 61 patients (90%, CI 95%, 79.9 +/- 95.8). In most cases the Müller manoeuver best demonstrated the collapse. The predominant obstruction was in the nasopharyngeal region (72%, mainly associated to changes in soft palate), followed by obstruction in the oropharyngeal region at the base of the tongue (29%). Multiple localization of the obstruction was observed in 19 patients. CONCLUSIONS: Endoscopy performed during arousal may allow the identification of the site and cause of obstruction in most of the patients with rhoncopathy and sleep apnea syndrome, thus aiding in the selecting the most adequate treatment for the patient.

Endoscopy↗
PubMed1994

Simplified exercise test for the initial differential diagnosis of Pneumocystis carinii pneumonia in HIV antibody positive patients.

BACKGROUND: This study was designed to evaluate the usefulness of a simplified exercise test in the differential diagnosis of Pneumocystis carinii pneumonia (PCP). METHODS: Forty five subjects with antibodies against the human immunodeficiency virus (HIV) and pneumonia were included and divided into two groups: those with PCP and those with "other pneumonias" (non-PCP). The test involved pedalling for two minutes on a stretcher bed and was considered positive if SaO2 decreased by at least 3%. RESULTS: During the exercise the mean(SE) SaO2 fell in patients with PCP from 88(4)% to 84(3)%, p < 0.01, whilst it improved slightly in subjects with non-PCP from 91(1)% to 93(3)%, p < 0.05. Sensitivity was 77% and specificity 91%. CONCLUSIONS: This simple test seems potentially useful for the initial investigation of HIV antibody positive patients with pneumonia.

Adult↗
PubMed1994

[Neutrophilia in the bronchoalveolar lavage of patients with AIDS and Pneumocystis carinii pneumonia. Reflections on its prognostic value in the Spanish setting].

The prognostic value of neutrophilia (> 5%) in bronchoalveolar lavage (BAL) in our context is studied in 21 patients with AIDS and Pneumocystis carinii pneumonia. Neutrophilia does not seem to be a good prognostic indicator in our context. We have found this condition, with a mean of 6 +/- 4%, in only 33% of our sample. The sensitivity of this parameter with respect to risk of death was very low (25%), while specificity was moderate (65%). In contrast with what has been reported in studies done with Anglo-Saxon populations, neutrophilia in BAL is probably of little prognostic use in our context. This may be due to various factors, among them the type of population (most being intravenous drug users) and the therapeutic protocol (early empirical treatment).

AIDS-Related Opportunistic Infections↗
PubMed1993

Diaphragmatic activity induced by cortical stimulation: surface versus esophageal electrodes.

Evoked responses of the diaphragm can be induced by magnetic cortical stimulation and recorded by either surface or esophageal electrodes. The former recording system is tolerated better by the patient but has potential problems with the specificity of the diaphragmatic signal. This study compares the responses of the diaphragm to cortical stimulation that were recorded simultaneously with surface and esophageal electrodes on seven patients (61 +/- 4 yr) with chronic obstructive pulmonary diseases. Stimuli were delivered in three ventilatory conditions: at baseline, during deep breathing, and during voluntary panting. No differences were observed between results recorded by surface and esophageal electrodes [amplitude of the compound motor of the action potential (CMAP), 0.8 +/- 0.1 vs. 0.8 +/- 0.1 mV, NS; latency, 13.1 +/- 0.4 vs. 12.6 +/- 0.5 ms, NS]. In addition, significant correlations were found (CMAP, r = 0.77, P < 0.001; latency, r = 0.71, P = 0.002). The concordance analysis, however, indicated some dissimilarity between the recordings of the electrodes (CMAP, R1 = 0.31; latency, R1 = 0.26). These differences may be due to the area of the muscle mainly recorded by each electrode and/or to the additional activity from other muscles recorded by surface electrodes. On the other hand, the diaphragmatic responses observed in these patients with chronic obstructive pulmonary diseases were similar to those previously reported in healthy subjects.

Action Potentials↗
PubMed1993

Pneumatoceles and pneumothorax after Pneumocystis carinii pneumonia.

Pneumocystis carinii pneumonia (PCP) is common in patients with AIDS. The usual chest X-ray pattern is a diffuse interstitial pulmonary infiltrate. Nevertheless, unusual roentgenographic forms can appear. A patient with PCP that resulted in pneumatoceles and a further pneumothorax is described.

AIDS-Related Opportunistic Infections↗
PubMed1992

[Sepsis caused by Mycobacterium tuberculosis in patients with AIDS].

BACKGROUND: Techniques for detecting mycobacteria in blood can be a good alternative for diagnosing tuberculosis in acquired-immunodeficiency syndrome patients (AIDS). PATIENTS AND METHODS: Eleven patients with AIDS and pulmonary tuberculosis, and four controls with AIDS and without tuberculosis were studied. The diagnosis of mycobacteremia was made by the identification of the microorganisms in blood. The method used was a lysis-centrifugation with subsequent stain or culture identification in different media (agar Löwenstein-Jensen, M7H9, M7H11, brain-heart infusion and Sauton broth). RESULTS: In one case, direct staining of sample was positive. The culture results were positive in all 11 patients with tuberculosis and in none of the controls. M7H11 was the media that allows the fastest detection. CONCLUSIONS: This technique can be a good alternative method for tuberculosis diagnosis in AIDS patients. Is easy to perform, relatively fast an with diagnostic performance. It also could be of interest in extra-pulmonary tuberculosis.

Acquired Immunodeficiency Syndrome↗
PubMed1992

[Antigenic response against PPD and antigen 60 in tubercular patients: single antigen versus the combined test].

We analyze serum samples from 70 patients with pulmonary tuberculosis and 50 healthy individuals. The antigenic activity (IgG) against protein purified antigen (PPD) and antigen 60 (A60) from M. tuberculosis. Thirteen patients were also HIV infected, and three patients had AIDS defined by the presence of disseminated tuberculosis. The test using antigen alone showed a 77% sensitivity and 74% specificity when PPD is used. When A60 was used, both values improved (81% sensitivity, 94% specificity). The use of a combined test (PPD and A60) improves the sensitivity (89%) but reduces the specificity (82%). The HIV infected patients showed similar responses to those of other patients. The combined use of different antigens might be useful for diagnosing tuberculosis.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Ototoxic reaction to erythromycin.

We report a case of bilateral hearing loss in a patient treated with intravenous erythromycin lactobionate. The ototoxic reaction occurred despite the patient's having normal renal and hepatic function and the fact that serum erythromycin levels were within the predicted normal range. In addition to hearing loss, a marked labyrinthic hyporreflexia was also observed. Hearing loss improved after the treatment was discontinued, but labyrinthic abnormalities persisted suggesting that erythromycin had caused a permanent vestibular damage.

Erythromycin↗
PubMed1991

Mechanisms of abnormal gas exchange in patients with pneumonia.

The mechanisms of abnormal gas exchange in patients with pneumonia and the gas exchange response while breathing high inspired O2 concentrations have not been clearly elucidated. To this end, we studied 23 inpatients with pneumonia and mild to severe arterial hypoxemia and/or increased alveolar - arterial O2 difference. Ventilation-perfusion (VA/Q) distributions were obtained upon breathing room air (or maintenance inspired oxygen fraction) and 100% O2 in random order. Subjects were divided in two groups according to whether they were spontaneously breathing (SB, n = 13) or their lungs were mechanically ventilated (MV) because of acute severe respiratory failure (n = 10). The SB patients showed only small amounts of shunt (7 +/- 2%) (mean +/- standard error) and moderate VA/Q mismatching, characterized by the presence of a small percentage of blood flow to low VA/Q units (VA/Q less than 0.1) (4 +/- 1%). In contrast, patients whose lungs were MV had larger shunts (22 +/- 5%) and greater percent of perfusion to low VA/Q units (11 +/- 5%). While breathing 100% O2, shunt remained unchanged but the dispersion of the pulmonary blood flow distribution (log SDQ) (normal range, 0.3-0.6) increased in each group (from 1.04 +/- 0.10 to 1.29 +/- 0.13 in SB and from 1.40 +/- 0.11 to 1.64 +/- 0.14 in MV; P less than 0.05 each), suggesting release of hypoxic pulmonary vasoconstriction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Mechanisms of gas-exchange impairment in idiopathic pulmonary fibrosis.

To investigate the mechanisms of pulmonary gas-exchange impairment in idiopathic pulmonary fibrosis (IPF) and to evaluate their potential relationship to the CO diffusing capacity (DLCO), we studied 15 patients with IPF (mean DLCO, 52% of predicted) at rest (breathing room air and pure O2) and during exercise. We measured pulmonary hemodynamics and respiratory gas-exchange variables, and we separated the ventilation-perfusion (VAQ) mismatching and O2 diffusion limitation components of arterial hypoxemia using the multiple inert gas elimination technique. At rest VA/Q mismatching was moderate (2 to 4% of cardiac output perfusing poorly or unventilated lung units), and 19% of AaPO2 was due to O2 diffusion limitation. During exercise VA/Q mismatch did not worsen but the diffusion component of arterial hypoxemia increased markedly (40% AaPO2, p less than 0.005). We observed that those patients with higher pulmonary vascular tone (more release of hypoxic pulmonary vasoconstriction) showed less pulmonary hypertension during exercise (p less than 0.05), less VA/Q mismatching [at rest (p less than 0.005) and during exercise (p less than 0.0025)], and higher arterial PO2 during exercise (p = 0.01). We also found that DLCO corrected for alveolar volume (KCO) correlated with the mechanisms of hypoxemia during exercise [VA/Q mismatching (p less than 0.025) and O2 diffusion limitation (p less than 0.05)] and with the increase in pulmonary vascular resistance elicited by exercise (p less than 0.005). In conclusion, we showed that the abnormalities of the pulmonary vasculature are key to modulate gas exchange in IPF, especially during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗