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Biomedical subjects

G Marti

Publications and source records attributed to G Marti.

29 records · Page 2Linked to original sources
PubMed1989

Cardiac autonomic dysfunction in obese subjects.

1. The prevalence of cardiac autonomic alterations was evaluated in 23 obese subjects with body mass index 37.2 +/- 3.03 kg/m2 (mean +/- SD), compared with 78 controls with body mass index 22.5 +/- 2.6 kg/m2 (P less than 0.001). 2. Cardiac autonomic function was assessed by four standard tests (heart rate response to deep breathing and to the Valsalva manoeuvre, systolic blood pressure fall after standing and diastolic pressure rise during handgrip) and by the cross-correlation test, a new method of computerized analysis of respiratory sinus arrhythmia based on spectral analysis of electrocardiographic and respiratory signal. 3. Considering tests indicative of parasympathetic function, only the heart rate response to the deep breathing and the cross-correlation test were significantly lower in the obese than in the control group [deep breathing = 13.95 +/- 8.65 beats/min (mean +/- SD) vs 24.5 +/- 7.65, P less than 0.001; cross-correlation 4.28 +/- 0.74 units vs 5.14 +/- 0.63, P less than 0.001]. Deep breathing and/or cross-correlation were abnormal in 10 (43.5%) obese subjects (deep breathing: seven subjects, cross-correlation: eight subjects). No significant difference between groups was found for the response to the Valsalva manoeuvre: the Valsalva ratio was 1.69 +/- 0.45 in obese subjects and 1.88 +/- 0.33 in controls (P = NS). The Valsalva ratio was abnormal in three obese subjects. 4. No significant differences were found between groups for tests indicative of sympathetic function.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Cross correlation of heart rate and respiration versus deep breathing. Assessment of new test of cardiac autonomic function in diabetes.

Cross correlation is a mathematical function whereby spectral analysis is used to describe the relationship between heart-rate fluctuations (256 R-R intervals) and respiration (simultaneously obtained by pneumotacograph). To assess its usefulness for testing autonomic integrity, cross correlation and deep breathing were compared in 141 diabetic subjects (aged 39 +/- 14 yr) and in 77 control subjects (aged 33 +/- 13 yr). To characterize patients, Valsalva maneuver, 30:15 ratio, tilt, and handgrip tests were performed in 96 of these patients; 23 had two or more abnormal tests (group A), 28 had one (group B), and 45 had none (group C). Sensitivity to parasympathetic withdrawal was compared in 9 control subjects (aged 26 +/- 4 yr) by four sequential 0.01-mg/kg i.v. atropine administrations. Reproducibility was compared in 11 control subjects (aged 25 +/- 2 yr) by repeating the tests four times for 2 consecutive days. Considering all 141 patients, cross correlation and deep breathing were less than 2SD of the mean of control subjects in 64 and 36 subjects, respectively. Considering patients who also performed other tests of autonomic function, cross correlation and deep breathing were less than 2SD of the mean of controls in 42 and 30 subjects, respectively (group A, 20 and 15; group B, 12 and 9; group C, 10 and 6). Cross correlation had better reproducibility than deep breathing (C.V. 10.3 vs. 30.6% at 6 breaths/min) and greater sensitivity to atropine (after the 1st injection, cross correlation and deep breathing decreased to 34.6 and 48.2% of baseline values, respectively; P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

IL-2-dependent expansion of CD3+ large granular lymphocytes expressing T cell receptor-gamma delta. Evidence for a functional receptor by anti-CD3 activation of cytolysis.

The nature and function of the TCR on PBL of a patient with a chronic CD3+ large granular (LGL) proliferation was studied. Fresh peripheral blood from this individual was comprised of 80% lymphocytes, 65 to 75% of which were CD3+, CD8+, Leu-7+ LGL. Of these LGL, 72% initially expressed the TCR-alpha beta heterodimer, whereas 21% did not. Cytotoxicity directed against MHC-unrestricted targets was minimal. After several days of exposure to rIL-2, cytotoxic activity was greatly enhanced, correlating with a disappearance of CD3+ cells expressing the alpha beta heterodimer. Twelve days after rIL-2 exposure, the LGL expressed only TCR-gamma delta heterodimer in association with CD3 and alpha beta heterodimer expression could no longer be detected. The TCR/CD3 complex on these cells was demonstrated to be functional as anti-CD3 elicited an increase in cytoplasmic free calcium concentration, stimulated cytolytic activity, and stimulated granule enzyme secretion from the LGL.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1983

B4, a human B lymphocyte-associated antigen expressed on normal, mitogen-activated, and malignant B lymphocytes.

The characterization of a new B cell-specific antigen (B4) is described in this report. With the use of a monoclonal antibody to B4, it was shown that B4 is present on B cells isolated from peripheral blood and lymphoid organs, on cell lines derived from normal and malignant B cells, and on tumor cells isolated from patients with B cell-derived neoplasms. B4, in contrast, was not detected on normal, activated, or malignant cells of T or myeloid origin. The B4 antigen is distinct from known B cell antigens, including sIg, Ia, B1, B2, Fc, and C3. Examination of mitogen-stimulated B lymphocytes suggests that the B4 antigen initially increases with B cell activation and then is lost at the terminal stage of B cell differentiation. Moreover, the observation that B4 is expressed on almost all early B cell tumors suggests that it may precede B1, CALLA, cytoplasmic mu, and B2 in early B cell ontogeny.

Animals↗
PubMedDate not supplied

Relationship between retinal ischemia and cardiovascular autonomic damage in diabetes.

In order to investigate the relationship between ischemic diabetic retinopathy and cardiac autonomic dysfunction we studied 40 diabetic patients (mean age +/- SEM: 48 +/- 2 years). Retinopathy was evaluated by fluorescein angiography and patients were divided into three groups: a) with ischemic retinopathy (15 patients), b) with edematous retinopathy (13 patients) and c) without retinopathy (12 patients). Cardiac autonomic function was assessed by 4 tests based on cardiovascular reflexes (heart rate response to Valsalva maneuver and to deep breathing; systolic blood pressure fall after standing and diastolic blood pressure rise during handgrip) and by the cross-correlation test, a computerized technique for the analysis of respiratory sinus arrhythmia based on spectral analysis of electrocardiographic and respiratory signals. Abnormalities of cardiac autonomic tests were present in 26/40 patients (65%); considering the retinal angiographic classification, autonomic test abnormalities were found in 13/15 (86.6%) patients with ischemic retinopathy, in 7/13 (53.9%) patients with edematous retinopathy and in 6/12 (50%) patients without retinopathy. The prevalence of cardiac autonomic dysfunction was significantly higher (p less than 0.005) in the ischemic retinopathy group compared to the other groups. These results show a strong association between ischemic retinopathy and cardiac autonomic dysfunction.

Autonomic Nervous System↗
PubMedDate not supplied

Bedside diagnosis of cardiac autonomic damage by computerized analysis of heart rate-respiration relationship.

In this study we propose a method for the analysis of the relationship between heart rate changes and respiration as a possible diagnostic tool for cardiac autonomic damage. The method consists in recording R-R intervals and respiratory amplitude by a suitably equipped personal computer, and by evaluating the cross-correlation peak between the two signals. This mathematical function appeared to be more sensitive to the degree of concordance between the two signals, rather than their absolute amplitude. The cross-correlation appeared to be lower in diabetics with autonomic dysfunction, markedly decreased after injection of atropine (only in normals), slightly increased after propranolol. Hyperpnea increased the cross-correlation peak between 3-18 breaths/min in normals, but only at lower frequencies, if at all, in diabetic subjects with various degrees of autonomic dysfunction. The cross-correlation showed the best reproducibility among R-R change tests. These preliminary results suggest that this method may provide new information on autonomic integrity and a substantial advantage in terms of reproducibility.

Adult↗