Biomedical subjects

L Bernardi

Publications and source records attributed to L Bernardi.

At least 235 records · Page 13Linked to original sources

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↗

PubMedDate not supplied

Subband modeling of the human cardiovascular system: new insights into cardiovascular regulation.

We present a new approach to cardiovascular analysis based on a well-known signal processing technique, namely, the frequency subband decomposition. The subbands are chosen in accordance with physiological standards: (1) 0-0.04 Hz, (2) 0.04-0.15 Hz, (3) 0.15-0.4 Hz. It is shown that such a pre-processing drastically improves the accuracy of the analysis and introduces a new direction in the understanding of the relationships between cardiovascular signals.

Adult↗

PubMedDate not supplied

Effect of rosary prayer and yoga mantras on autonomic cardiovascular rhythms: comparative study.

OBJECTIVE: To test whether rhythmic formulas such as the rosary and yoga mantras can synchronise and reinforce inherent cardiovascular rhythms and modify baroreflex sensitivity. DESIGN: Comparison of effects of recitation of the Ave Maria (in Latin) or of a mantra, during spontaneous and metronome controlled breathing, on breathing rate and on spontaneous oscillations in RR interval, and on blood pressure and cerebral circulation. SETTING: Florence and Pavia, Italy. PARTICIPANTS: 23 healthy adults. MAIN OUTCOME MEASURES: Breathing rate, regularity of breathing, baroreflex sensitivity, frequency of cardiovascular oscillations. RESULTS: Both prayer and mantra caused striking, powerful, and synchronous increases in existing cardiovascular rhythms when recited six times a minute. Baroreflex sensitivity also increased significantly, from 9.5 (SD 4.6) to 11.5 (4.9) ms/mm Hg, P<0.05. CONCLUSION: Rhythm formulas that involve breathing at six breaths per minute induce favourable psychological and possibly physiological effects.

Adult↗

PubMedDate not supplied

Feasibility of a cell kinetic-based adjuvant chemotherapy trial in axillary node-negative breast cancer.

AIMS AND BACKGROUND: Accumulated information on biologic prognostic indicators and predictors of response to different types of treatment in patients with different tumor characteristics has made it possible to design clinical protocols on biologic bases. Among cell proliferation indices, the thymidine labelling index (TLI) has proved to be an independent and consistent prognostic indicator over time. Moreover, experimental and retrospective analyses of clinical studies have revealed a direct relation between TLI and response to chemotherapy. On the basis of the results, a prospective clinical protocol on axillary node-negative breast cancer was activated in Italy in 1989. METHODS: Patients with low TLI tumors were treated with local-regional therapy alone, whereas patients with high TLI tumors were randomized to receive local-regional therapy followed or not by adjuvant chemotherapy consisting of 6 cycles of CMF. RESULTS AND CONCLUSIONS: The present paper reports on the feasibility of a prospective clinical protocol based on a subgroup of patients with specific pathologic (node negative) and biologic (rapidly proliferating) breast cancers. However, patient eligibility was only 11%.

Adult↗

PubMedDate not supplied

[Significance of the electric current characteristics used in rheography. Study on the relationship between frequency, voltage and intensity of the current with reference to impedance values of the body mass].

Impedance variations of corporeal segments were evaluated in relation to the variations in current frequency and intensity using a tetrapolar measuring apparatus. The results appear to confirm the reliability of the technique and, on the basis of the study of current transmission in the segment, it is suggested that frequencies between 70 and 240 KHz. particularly around 140 KHz, are the most suited to this type of measurement.

Electrodiagnosis↗

PubMedDate not supplied

Correlation between p53 gene mutations and p53 protein accumulation evaluated by different methodologies.

Mutations in the p53 gene are the most common genetic alterations in many tumour histotypes. Many of these mutations induce conformational changes resulting in p53 protein stabilisation and consequently an accumulation detectable with immunochemical methods. Available data on the correlation between p53 gene alterations and p53 overexpression widely vary. In this study we analysed the correlation between p53 gene alterations detected by DGGE, SSCP and sequencing and protein expression detected by flow cytometric and immunohistochemical approaches by using PAb 1801 antibody. The study was performed on 21 bladder tumours and 10 cell lines derived from different tumour histotypes as representative of different methodologic problems which can be met starting from different types of biological material. The best correlation (81%) was observed between p53 mutations and FCM results, using a double evaluation criterion for the latter which includes the percentage of positive cells and "delta values", evaluated as the difference between the mean values of Pab 1801 stained cells and isotypic control. The high correlation obtained between results from this FCM double criterion and p53 gene mutations is a good starting point for the analysis on large series of tumours and for a multiparameter FCM analysis including p53 protein levels.

Carcinoma, Transitional Cell↗

PubMedDate not supplied

[Functions and changes of chemoreflex in physiological and pathological conditions].

Chemoreceptors are known to respond to changes in composition of the gases in the inspired air by changing pulmonary ventilation. Whereas, less known it is the role that they play in many both physiologic and pathologic conditions. In this review we do not only consider the anatomic and physiologic chemoreceptor features but also we analyse the relationship between chemoreflex and baroreflex in the cardiovascular control, their role in the pathogenesis of essential hypertension and in the increase of blood pressure in subjects affected by obstructive sleep apnea, their implication in the genesis of dyspnea in chronic heart failure and their role in pulmonary disease. In this review we also analyse the chemoreflex changes with relation to physiologic situations such as aging, obesity, exercise, training and high altitude. Three methods are described for the study of the chemoreflex function, but more attention is paid to the new rebreathing technic. The aim of this paper is to underline the interactions between chemoreceptors and cardiovascular system and to analyse their functional changes in both physiologic and pathologic conditions.

Adult↗

PubMedDate not supplied

[Blood histamine during submaximal muscular work].

Blood histamine was measured in 20 healthy males before and after performance of rectangular type submaximal work. The results show that following muscular work there is an increase in the blood concentration of the substance in all the subjects examined, the average increase being 33% although variations from one subject to another were considerable. It is hypothesized that the increase in the histamine level can be explained by admitting an increase in histidine-decarboxylase activity at tissue level with consequent synthesis of a greater quantity of histamine. It is also hypothesized that an excess of blood histamine may be of importance in the organism's general adaptation reaction to stress.

Adaptation, Physiological↗

PubMedDate not supplied

[Quadriplegia and prolonged respiratory insufficiency due to tick-borne encephalomyelitis. Case report].

Tick-borne encephalitis (TBE) is an uncommon and potentially severe illness. TBE virus is transmitted to the humans by an infected tick and it spreads to the central nervous system determining various clinical pictures. A case in which TBE virus caused an encephalomyelitis with quadriplegia and respiratory insufficiency that persist one year after the diagnosis, is reported. Such a clinical manifestation of TBE has never been described in Italy till now.

Adult↗

PubMedDate not supplied

[To delay may be wise].

We report a case of acute renal failure, quickly evolved, in which the coexistence of parenchimal nephropaty and renal mass, have induced not a common diagnostic and therapeutic approach, finalized to optimize the interventional nephrology procedures, with the use of various imaging procedures. It is followed a multidisciplinar therapeutic approach, with the employment of dialysis, steroid therapy and surgical treatment.

Acute Kidney Injury↗

PubMedDate not supplied

Microcomputer-aided diagnosis in cardiology. An expert system based on clinical and phono-mechanocardiographic data.

A knowledge-based consultation system capable of making multiple diagnoses in noninvasive cardiology is presented here. The system, expressly designed for a personal computer, is able to provide assistance in the diagnosis of 49 disease-entities. When tested in 52 retrospective cases (33 patients with one disease-entity, 17 with two, 2 with three), it made 39 correct diagnoses (75%). The average score of the actually present disease-entities was 94 +/- 3.2 (mean +/- standard error of the mean), significantly higher than the highest score obtained by the incorrect diagnoses (87.2 +/- 3.1) (p less than 0.001). The system was able to correctly perform 1 triple diagnosis and 9 double diagnoses. The results obtained, comparable with those of well-known expert systems (MYCIN, INTERNIST-1), demonstrate the reliability of a microcomputer-based expert system for medical diagnosis in cardiology.

Diagnosis, Computer-Assisted↗

PubMedDate not supplied