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Biomedical subjects

A Matani

Publications and source records attributed to A Matani.

At least 19 recordsLinked to original sources
PubMed2004

MEG latency difference measurement for priming experiments.

Latency analysis of magnetoencephalography (MEG) for priming experiments, not in motor readiness level but in cognition level, may be useful for identification of the brain system. We performed a masked priming experiment for repetitive presentation of visual words. The subjects of the experiment were asked to perform a categorization task and button-pressing. The stimuli of the experiment consisted of mask (duration: 700 ms) - prime (70 ms) - target (1000 ms). There were four types of experiment which depended on the combinations of primes and targets: #1) in-category/in-category; #2) pseudo-characters/in-category; #3) out-category/out-category; and #4) pseudo-characters/out-category. As a result, the order of reaction times (RTs) were #1 < #2 < #3 approximately #4. We performed MEG recording with the above experiment simultaneously. Due to such a short stimulus onset asynchrony (SOA) of 70 ms and higher-order brain activity for language processing, the MEG activity continued for several hundred milliseconds, did not have conspicuous peaks, and could not be separated in the prime and target responses. This kind of MEG data is difficult to investigate with conventional signal processing methods, such as subtraction or signal source estimation. We applied a pattern analyzing method that measured the similarity time course between two sets of MEG data. The similarity time courses between experiments #3 and #4 and the other experiments were calculated. The order of the peak latencies of the time course was the same as that of RTs.

Humans↗
PubMed2001

High prevalence of HCV infection among the general population in a rural area of central Italy.

The hepatitis C virus infection (HCV) is the most frequent cause of hepatic infection in Europe. In Italy, anti-HCV positivity values are extremely variable, depending on the age and geographic location of the population being analysed. The aims of the study were: (1) evaluating positivity for anti-HCV antibodies in various age groups and determining the HBsAg in a mountainous and predominantly farming area in central Italy; (2) assessing some anamnestic and clinical variables through a questionnaire, submitted during the taking of blood samples, in order to determine HCV exposure and risk factors for the target population. 344 subjects selected by random sampling among 3308 people, older than 16, were considered as the target population. A prevalence study was carried out. The sources of data were: blood samples taken to carry out the HCV positivity test; a questionnaire including items about exposures at risk and case-historical and clinical patient data. The risk of infection was evaluated by a multiple logistic regression model. The inferred HCV+ prevalence rate is 22.4/100 (95% confidence interval (CI): 20.8-24.1). An increasing age trend is shown with a higher positive predominance among females (28.99/100 vs. 14.29/100 in males). The positive HBsAg prevalence in the examined survey is 1.2/100. Variables associated with the HCV occurrence are case history of pneumonopathy (OR: 4.9) and exposure to parenteral therapies with glass syringes (OR: 3.3). This study is consistent with literature about the hypothesis of a north-south geographic gradient in the hepatitis C occurrence in Italy. Data clearly show the effects of the inappropriate use of medical or surgery practices on the population, with particular reference to the use of glass syringes. No elements prove that the farming features of the area may be predictive of HCV infection risk. The extent of the recorded prevalence values calls for the implementation of programmes aimed at detecting clusters or population areas at risk.

Adult↗
PubMed1999

A compression and transmission system of ultrasonic image sequence for telemedicine.

OBJECTIVE: A newly developed compression and transmission system of ultrasound image sequence for telemedicine is proposed for transmitting ultrasonic image sequence in real time via IP-connected computers for telemedicine. MATERIALS AND METHODS: In the compression method, the characteristics of ultrasound images were taken into account. Only sound data were essential, and the histogram of the images had two narrow distributions around black-and-white areas. The sound data, therefore, were run length encoded and then transmitted. In the transmission, UDP/IP was employed with a time weight insertion among the packets so as not to overflow the data buffers of computers in this system to derive the maximum transmission performance up to the network capacity. The decompression method was the same as the generation of the sector scan images from the sound data, so that natural ultrasound image sequence could be obtained. RESULTS: This system was evaluated by transmitting the ultrasonic image sequence of the heart via ISDN (1. 5 mbps). Although this system completely specialized in compression and transmission of the ultrasound sector scan image sequence, a relatively good performance in the frame rate and the image quality was achieved, compared with the previous systems (H.260, JPEG, and MPEG-1).

Heart Diseases↗
PubMed1995

Functional localization of bilateral auditory cortices using an MRI-linked whole head magnetoencephalography (MEG) system.

In 20 healthy subjects, auditory evoked magnetic fields were measured over the entire head, using a helmet-shaped 66-channel MEG system linked to MRI. When the left or right ear was stimulated by 60 msec 2 kHz tones, the prominent 100 msec response (N100m) appeared significantly earlier in the contralateral hemisphere than in the ipsilateral one. In 16 cases, the N100m dipolar field patterns were clear in both hemispheres, overlapping each other across the midline. The N100m sources were estimated using a 2-dipole model in a spherical conducting medium with the size and location of the sphere determined individually according to the MRI images. No differences were found between the contralateral and ipsilateral N100m dipole positions in one hemisphere. When superimposed on MRI, the N100m dipoles were located precisely on the upper surface of bilateral temporal lobes with a standard deviation of 2.2 mm in the superior-inferior direction. In 16 right handed males, the right hemispheric N100m dipoles were 6 mm anterior to the left hemispheric dipoles. The whole head MEG is suitable to see small but significant differences of bilateral cerebral function, with exceptionally high spatial resolution, confirmed by the MRI-linked system.

Adult↗
PubMed1994

[Whole head measurement of auditory evoked magnetic field using a MR-linked helmet shaped MEG system].

Authors compared MR anatomy and magneto-encephalographic (MEG) functional methods in locating auditory cortex in 20 normal volunteers and 56 patients with intracranial structural lesions. Auditory evoked response was measured over the entire head, using a helmet shaped 64 channel MEG system. In each subject, three dimensional MR image was obtained with identical coordinate system of MEG. Best fit sphere to each subject's head was calculated from MRI data. Signal source of auditory evoked MEG was estimated using a two dipole model in the best fit sphere. Position and orientation of dipoles were superimposed on each subject's MRI. Both left and right dipolar patterns appeared about 100 ms after unilateral auditory stimuli (N100m) in 19 normal subjects and 47 patients. These dipolar patterns overlap each other across the midline. A two dipole model successfully localized bilateral N100m dipoles in the upper surface of superior temporal planes. N100m response was missing unilaterally in 1 normal subjects and 9 patients inspite of normal audiometry findings, suggesting sub-clinical auditory dysfunction. The MR-linked whole head MEG is a non-invasive tool to localize source of auditory evoked N100m response even in the case with intracranial structural lesions.

Acoustic Stimulation↗
PubMed1990

Low-dose dopamine during cardiopulmonary bypass in patients with renal dysfunction.

Thirty-six patients with preoperative renal dysfunction were studied to evaluate the effects of dopamine (D) and dopamine-nitroprusside (DN) on renal function during cardiopulmonary bypass (CPB). No differences from the control group (C) were found in creatinine clearance, fractional sodium excretion, osmolarity and free-water clearance. Sodium output/intake ratio during CPB was higher in group D than in groups C and DN (P less than 0.05); water output/intake ratio was higher in group D than in group C (P less than 0.05). Urine lysozime levels and alpha-glycosidase/creatinine ratios increased similarly in the three groups, suggesting ischemic tubular cell damage. No patients showed acute postoperative renal failure or a worsening of their renal dysfunction. The data suggest an increased water and sodium excretion during CPB with a dopamine infusion, possibly resulting from a renal vasodilator effect that was abolished by simultaneous nitroprusside administration.

Aged↗
PubMed1990

[Single cell preparation of the human heart. Technic of dissociation and isolation of myocytes].

This paper describes a procedure of cellular dissociation which allows the isolation of single cells from the human heart while preserving their integrity and physiological function necessary for electrophysiological studies in vitro. During open heart surgery, biopsies were obtained from the right atrium of the beating heart in 16 patients immediately before starting the extracorporeal circulation. The tissue was immediately placed in a cardioplegic solution at 4 degrees, and subsequently in a free-calcium solution at 20 degrees from 20' to 30'. It was then exposed to the proteolytic action of Collagenase type I and Protease type VII (Sigma Chemical Co., St Louis, USA) at 35 degrees for a maximum of 5 hours. The cells were finally transferred into a Tyrode solution at room temperature. With this method we obtained up to 70% of intact human myocytes, 40% of which calcium-tolerant. The subsequent electrophysiological studies performed showed that the cells maintained their morphological and physiological properties.

Adult↗
PubMed1989

[Pseudomonas aeruginosa infection of the sternum and costal cartilages in cardiosurgery. Therapeutic experience using aztreonam].

Clinical effectiveness of Aztreonam was studied. This new monobactam antimicrobial agent was tasted in the treatment of post-operative infectious complications of cardiac surgical sternal wounds. Ten patients (4 men and 6 women, age range 20 to 68 years) were entered into the study. All had a Pseudomonas aeruginosa infection of sternum or sternum and ribs and all underwent an extensive regional surgery of the infection wound and received a topical and/or IV treatment with Aztreonam. In all cases we obtained a satisfactory result, with complete eradication of the infection. Both local and systemic tolerance to the drug were excellent and no side-effect was registered. Therefore Aztreonam can be considered an active and safe antibiotic for the treatment of sternal and/or costal postsurgical infections by Pseudomonas aeruginosa.

Adult↗
PubMed1988

Protection of the heart by nifedipine cardioplegia during coronary artery surgery. A clinical-haemodynamic evaluation.

This study was undertaken to evaluate the myocardial preservation obtained by adding a Ca++ channel blocker, nifedipine, to cold potassium cardioplegia (4 mcg/Kg/L) in 24 patients undergoing coronary artery surgery. They were randomly divided into a treated (N) and a control (C) group. Significant differences between the two groups were noted in the cardiac arrest time (p less than 0.001), in the mechanical recovery mode (p less than 0.01) and in the inotropic support needed (p less than 0.01). Cardiac index increased significantly in group N but decreased in group C (p less than 0.01). Peripheral delta P/delta t and endocardial viability ratio (EVR) decreased in both groups. Coronary sinus and serum CK and CK-MB release were significantly lower in the treated group. ECG ischaemic changes occurred in 8 patients in group C but only in 1 case in group N (p less than 0.001). Arrhythmias occurred in 3 cases in group C (p less than 0.05). The incidence of perioperative myocardial infarction was not significant (2 cases in group C). These data suggest that nifedipine can protect the myocardial cell from ischaemic injury without depressing myocardial contractility or AV conduction.

Arrhythmias, Cardiac↗
PubMed1986

Diltiazem cold cardioplegia in coronary artery surgery: effects on myocardial function and ischemia.

This study was undertaken to evaluate the myocardial preservation obtained by adding a calcium channel blocker, diltiazem (200 mcg/kg of body weight) to cold potassium cardioplegia in 24 patients with coronary artery disease who underwent myocardial revascularization, and were randomly divided into a treated Group D and a Control Group C. No significant differences were noted between the groups in cardiac electrical arrest and recovery time, recovery rhythm, mechanical function recovery, inotropic support, stroke index, or cardiac index. After cardiopulmonary bypass, the stroke index decreased by 13.1% in Group D and by 20.7% in Group C; cardiac index increased in both--18.6% and 14.0%, respectively--but the results were possibly from compensatory heart rate increases. Peripheral deltaP/deltat and endocardial viability ratios decreased in both groups. Coronary sinus enzymes and serum CK were slightly lower in the treated group. Serum CK-MB, however, was significantly higher in the Control Group. Electrocardiographic ischemic changes occurred in four patients, all in Group C (p =.046). Hyperkinetic arrhythmias occurred in five of the controls, but in none of the treated patients (p =.018). One perioperative myocardial infarction was diagnosed in the Control Group. These data suggest that diltiazem has no negative side effects on hemodynamics or cardiac rhythm and does not reduce impairment of myocardial function due to ischemia, but it does decrease the incidence of ischemic lesions in patients undergoing coronary artery bypass procedures.

Journal Article↗
PubMed1982

Immunocytochemical demonstration of a1-Antitrypsin and a1-Antichymotrypsin in human gastrointestinal tract.

a1-Antitrypsin and a1-Antichymotrypsin were demonstrated by the peroxidase--antiperoxidase (PAP) technique in paraffin sections from various parts of the normal adult gastrointestinal tract. Thus, positive reaction for these two proteinase inhibitors was given by the absorptive epithelial cells of the small intestine and epithelial cells of Brünner's duodenal glands and the glands of the pyloric antrum. Our findings suggest that the presence of a1-Antitrypsin and a1-Antichymotrypsin in epithelial cells of the small intestine, may represent a self-protecting mechanism against the pancreatic proteolytic enzymes of the intestinal juices. The significance of our observation and its possible role in the previously reported a1AT deficiency associated with coeliac-like disease is also discussed.

Brunner Glands↗