Chest conduction properties and ECG equalization.

In common practice of detecting and recording biomedical signals, it is often implicitly assumed that the propagation, through the whole circuit human body-electrodes recording devices, is frequency and voltage independent. As a consequence, clinicians are not aware that recorded signals do not correspond faithfully to the original electrical activity of organs under investigation. We have studied the transmission of electrical signals in human body at various voltages and frequencies to understand if and to which extent the most diffused stimulating and recording techniques used in medicine are affected by global body conduction properties. Our results show that, in order to obtain a more faithful detection of electrical activity produced or evoked by human organs (e.g. EGG, electromyography, etc.), it is convenient to 'equalize'' recorded signals. To this purpose, two equalization techniques are proposed, based, respectively, on a simple hardware filtering during acquisition, or FFT post-processing of the acquired signals. As an application, we have studied the transmission of electrical signal in human chest and have compared equalized high frequency ECG signals with raw (original) recordings.

Hippocampal synaptic plasticity: effects of neonatal stress in freely moving adult male rats.

The present study examines the effects of neonatal isolation on hippocampal LTP in adult male rats. Changes in dentate granule cell population measures, i.e., EPSP slope and population spike amplitude (PSA), evoked by tetanization of the medial perforant pathway were used to assess the effects of neonatal isolation on LTP over a period of 96 h. Following tetanization significant group differences were obtained for input/output (I/O) response measures of EPSP slope and PSA, with isolated males showing consistently higher values than in the other two groups. Comparisons made at 1 h post-tetanization (establishment of LTP) indicated that isolated males showed significantly greater enhancement than any other group. At 96 h (maintenance of LTP), however, neonatally isolated males showed significantly greater enhancement than either non-isolated siblings or unhandled controls. Additionally, isolation resulted in prolonging the duration of enhancement obtained from males. Thus, males show different enhancement profiles with respect to both the magnitude and duration of LTP and neonatal isolation alters these profiles in profound manner.

Ethyl alcohol induced skin temperature changes evaluated by thermography. Preliminary results.

The authors have investigated the validity of thermography in the study of ethyl alcohol induced hand blood flow changes in normal subjects before and after a standard meal. The superficial temperature changes of the hand of ten healthy subjects, 7 males and 3 females, 25-40 years old, were recorded in 4 conditions: a) on an empty stomach, b) after ingestion of a standard dose of ethyl alcohol (25 cc of whisky at 40%, corresponding to 10 g of alcohol), c) after a standard meal (1200 Kcal), d) after a standard meal and a standard dose of alcohol. Three male subjects were not drinkers. Arterial blood pressure and ECG were monitored during the different phases of the experiment. Results show a typical time course of the hand temperature in response to intake of alcohol, stronger in fasting non drinkers subjects. Our results confirm the valuable role of thermography in the study of alcohol-induced calorigenic effects.

Some blood parameters of water buffalo in different physiological conditions.

The Authors have studied the changes of GOT, GPT, ALP, CPK and Se in buffaloes under different physiological conditions (age, diet, different pre and post partum times). 99 adult buffaloes were classified in 8 groups on the basis of different pre, post partum time intervals. Moreover, other 39 animals were divided into 4 groups: A = 60-90 day old animals, fed with reconstituted milk supplemented with Vit E; B = same age, fed with maternal milk; C = 6-8 month old animals; D = 12-18 month old animals. In the various classes of animals blood ALP, GPT, GOT, CPK and Se were monitored. Results showed that the high variability in blood activity of the studied enzymes suggest that in establishing their reference values the physiological condition of the subject and the time interval from the parturition must be taken into account. The fact that Se was not detectable in many pregnant animals suggests that the prevention of myodistrophy in buffalo calves must be effected in prenatal epoch.

Simultaneous evaluation of vitamins A and E in human plasma by normal phase HPLC.

The production of toxic oxidants such as H2O2; OH. and O2.- which follows aerobic metabolism is highly enhanced in aging, alcohol consumption and in a variety of degenerative diseases including neoplasias. Among the different antioxidant agents that in human organisms counterbalance the oxidative stress, which damages lipid, protein and DNA, are included beta-carotene, alpha-tocopherol, glutathione, ascorbate, ubiquinol and specific enzymes such as superoxide dismutase, catalase and glutathione peroxidase. In particular, vitamins A and E are the most important lipid-soluble antioxidants in human tissues protecting polyunsaturated fatty acid from peroxidation. In this paper we report an improved method, obtained after modification of a normal phase HPLC method, which allows the simple and rapid simultaneous evaluation of vitamins A and E in plasma. The separation of vitamins is achieved by eluting the HPLC column with a linear gradient from 1 to 5% isopropanol in n-hexane. The eluate is simultaneously monitored by U.V. and fluorescence detection to identify and quantify vitamins A and E, respectively.

Finger tremor and the central nervous system.

It is well known that normal physiological tremor of the fingers and alpha rhythm in the EEG, may share a common frequency band in the region of 10 Hz; that these two characteristics may be in some way related as a function of their frequencies, is a hypothesis which needs to be tested, as one element in establishing the physiology of physiological tremor. Bilateral occipital EEGs and simultaneous measurements of acceleration from the terminal phalanx of the middle finger of both hands were recorded from eight subjects. The data were analysed to produce power spectral densities and coherence functions, the latter being used to reveal the presence or absence of frequency elements common to both signals. No evidence was found that would support a hypothesis that the two characteristics were in any way frequency related, from which it can be inferred that the tremor is not under central control. In addition, tremor of the right and left hands does not show a synchronous relationship.

The serum lipoprotein pattern of water buffalo (Bubalus bubalis).

1. The serum lipoprotein pattern of water buffalo was studied by means of electrophoresis and the lipoproteins were isolated by ultracentrifugation on the basis of their hydrated density. 2. High density lipoproteins (HDL) showed a higher level of cholesterol than did the other lipoproteins. Moreover, the level of phospholipids was higher in HDL than in very low density lipoproteins (VLDL). 3. The buffalo B100 apoprotein was similar to that of man and rat. Three apoproteins similar to human apo E, apo AI and AII were found in buffalo HDL, buffalo VLDL contained essentially apo B protein.

Digital sampling rate and ECG analysis.

The influence of sampling rate on the accuracy of measurements of various ECG parameters has been studied. Statistical analysis showed no significant difference between results obtained at sampling rates of 500 and 250 samples s-1. Recordings made at 125 samples s-1, however, showed significant reductions in peak amplitude values. Some interval measurements also varied significantly to both larger and smaller values. Other intervals did not seem to be affected significantly. It is concluded that a sampling rate of 125 samples s-1 could be used in particular conditions when only the measurement of certain intervals is required.

[Erythrocyte deformability dependent on variations in pH]. / La deformabilita' degli eritrociti in rapporto a variazioni del pH.

Authors studied the influence of pH changes on red blood cell deformability by means of filtration technique. In 0,9% NaCl solutions, there was decrease of RBC deformability upon both lowering and increasing of pH. In Teitel solutions, RBC deformability increased on alcalyne pH.

[Erythrocyte deformability determined by filtration]. / Determinazione della deformabilita' degli eritrociti mediante filtrazione.

Authors studied red blood cell filtrability by means of an original apparatus. The red blood cells were suspended in 0,9% NaCl and Teitel solutions. Teitel solution was the most usefullness in filtrability studies.