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Biomedical subjects

D Medici

Publications and source records attributed to D Medici.

At least 19 recordsLinked to original sources
PubMed1998

Cardiac Troponin T to evaluate myocardial protection via intermittent cold blood or continuous warm blood cardioplegia in coronary artery bypass grafting.

BACKGROUND: The aim of our study was to evaluate the efficacy of myocardial protection during coronary artery bypass grafting (CABG) in cold blood intermittent (CBIC) and warm continuous blood cardioplegia (WCBC). To assess myocardial necrosis, Troponin T, a structural protein belonging to the troponin complex, was measured. Troponin T is released in the blood stream 4 hours after myocardial damage, and it does not cross-react with the isomeric form of the skeletal muscle. METHODS: Our study involved 20 consecutive patients, scheduled for isolated CABG. They were divided into two groups: the first group (10 patients; 8 m, 2 f) underwent surgery with the use of CBIC, the second group (10 patients; 9 m, 1 f) with WCBC. The serum levels of cardiac Troponin T (cTn-T) were all <0.2 microg/l before operation. RESULTS: In the CBIC the mean cTn-T peaked on the 1st day after CABG, in the WCBC group the first peak occurred in the 2nd hour after arrival in the intensive care unit, and the second peak occurred on the 4th day postoperatively. The mean serum cTn-T was lower in the WCBC vs CBIC group from the 1st to the 5th day postoperatively, with a statistical difference on the 1st day (p<0.05). In the CBIC group either the cTn-T peak values (r=0.77; p<0.02) or area under the concentration curve of cTn-T release (r=0.85; p<0.004), were directly correlated with the aortic cross-clamping time. This was not demonstrated in the WCBC. CPK and CK-MB peaked in both groups 6 hours after arrival in the intensive care unit and on the 1st day postoperatively, with higher values at 6 hours in the WCBC group (p<0.05). The CK-MB/CPK ratio was significantly lower in the WCBC group at the six hours (p<0.05). CONCLUSIONS: The results of this preliminary study suggest that fewer necrosis markers are released during CABG in the WCBC group; in the CBIC group the release of cTn-T whether measured by peak serum level or by area under the curve, shows a statistically significant correlation with cross-clamping time. Warm blood cardioplegia is safe and supplies adequate myocardial protection during CABG; the more prolonged cross-clamping is, the more myocardial protection is afforded by WCBC.

Aged↗
PubMed1996

Electrode positioning for reliable telemetry ECG recordings during social stress in unrestrained rats.

We describe a surgical procedure for optimizing the location of telemetry ECG leads in rats. The new location was aimed at obtaining an accurate representation of ECG features throughout the cardiac cycle by limiting the voltage instability usually observed during intense somatomotor activity and improving the signal-to-noise ratio. The two electrodes (wire loops) were fixed on the dorsal surface of the xiphoid process and in the anterior mediastinum close to the right atrium. The implantation procedure was fast, little invasive, and allowed animals to completely recover from intervention. The performance of the "improved" location (IL, n = 10) with respect to two subcutaneous (SC) positionings ("conventional positioning" CSP, n = 5; "updated location," USL, n = 5) was evaluated by comparing ECGs obtained in baseline, stress and recovery conditions and during different behavioral activities (immobility and grooming). The resident-intruder test (emotional/physical challenge) was chosen as experimental stress paradigm. The noise level of ECGs obtained from IL rats was lower than in CSP and USL animals, in all recording conditions. Percentages of correctly recognized beats (CRBs) over the total number of beats (TBs) were significantly higher in IL rats than in CSP and USL animals, both in baseline conditions (99% vs. 11% and 40%) and situations involving high somatomotor activity (stress: 97%, 5% and 16% recovery; 97%, 7% and 15%) (p < 0.01). The performance of IL as compared to CSP and USL was also better when percentages during grooming and immobility were considered (grooming: 93% vs. 4% and 23%: immobility: 97%, 6%, and 33%; p < 0.01).

Animals↗
PubMed1994

Unusual synkinetic movements between facial muscles and respiration in hemifacial spasm.

We describe two cases of hemifacial spasm (HFS) with unusual synkinetic movements between facial muscles and respiratory activity. Patient 1 developed an idiopathic HFS. She underwent microvascular decompression surgery, followed by transitory facial nerve palsy; she recovered but later developed a facial synkinesia characterized by involuntary and forced eyelid closure on spontaneous and deep breathing; the orbicularis oculi muscle was active also when her mouth was open (the so-called Marin-Amat syndrome). Patient 2, 1 year after a peripheral facial nerve palsy (Bell's palsy), developed an HFS together with synkinetic movements between the orbicularis oculi muscle and respiration. In both cases electrophysiological studies showed pathological synkinetic electromyographic activity. An enhanced hyperexcitability of brain stem interneurons and facial motoneurons could be suggested to explain the phenomenon.

Aged↗
PubMed1994

Migrant sensory neuritis associated with AIDS: case report.

We studied an AIDS patient who suffered from numbness, paresthesias and pain in the territories of different non-contiguous cutaneous nerves at different times. A transitory partial loss of touch and pinprick sensibility was also present in the same cutaneous areas. Sensory conduction velocities and SAP amplitudes were normal. The clinical picture was consistent with the Migrant Sensory Neuritis of Wartenberg. This rare neuropathy has never previously been described in patients affected by AIDS.

Acquired Immunodeficiency Syndrome↗
PubMed1994

On the cause of tendon areflexia in the Holmes-Adie syndrome.

A case of Holmes-Adie syndrome was studied clinically and electrophysiologically. A total loss of tendon reflexes was observed in upper and lower limbs. The main electrophysiological finding was a marked increase of the central conduction time after stimulation of peroneal and tibial nerves. Motor evoked potentials in soleus muscle after transcranial magnetic stimulation showed normal threshold and latencies. We suggest that tendon areflexia could be a consequence of a dysfunction of somatosensory large diameter afferent fibres at the spinal level.

Adie Syndrome↗
PubMed1992

Acute sensory and autonomic neuropathy: possible association with coxsackie B virus infection.

This report describes a 26 year old woman with a Coxsackie B virus infection complicated by an acute pandysautonomic and sensory neuropathy. Electrophysiological studies suggested an axonal neuropathy. A sural nerve biopsy performed early in the disease showed axonal degeneration with a virtual absence of unmyelinated fibres and moderate loss of myelinated fibres, mainly affecting the small fibres; this differs from previous reports. An immune-mediated or direct virus action might explain the pathogenesis of this unusual evolution of a viral infection.

Adult↗
PubMed1992

Presurgical electrophysiological findings in acoustic nerve tumours.

The clinical involvement of the facial nerve is a rare finding among the initial symptoms of acoustic neurinomas. However, compression of the facial nerve is a common intraoperative finding. Blink reflex was recorded in 20 patients affected by cerebellar-pontine angle tumor confirmed at surgery. Recordings were also made of the M-response of the facial nerve from the naso-labial folds. In 6 cases jaw reflex was also recorded. In summary, these electrophysiological studies revealed a facial nerve damage in 13 and a trigeminal nerve dysfunction in 2 out of 18 clinically unaffected patients. The combined study of the 3 tests proved to be useful when the blink reflex showed an isolated R1 delay, that is, in cases in which the level of damage along the trigemino-facial reflex arc cannot be defined by the recording of the blink reflex alone.

Adolescent↗
PubMed1991

Magnetic motor evoked potentials (MEPs) in masseter muscles.

Electromyographic responses of the masseter muscles and orbicularis oris muscles following transcranial magnetic stimulations were recorded with surface and needle electrodes. MEPs in masseter muscles (latency 6.9 +/- 0.71 ms, mean +/- SD) due to activation of controlateral cortico-nuclear connections were evoked by magnetic stimulations at 4 cm laterally to the vertex on the biauricular line. These MEPs were followed bilaterally by a silent period lasting about 20 ms and, less constantly, by a later silent period lasting up to 80 ms. The ipsilateral responses to the same stimuli presented shorter latencies and higher amplitudes and they were ascribed to direct stimulation of the trigeminal nerve, probably its intracisternal portion. Ipsilateral masseter "cortical" MEPs could be elicited only by a lower output setting (70% of the maximum output) of the stimulator. Orbicularis oris MEPs were polyphasic and dispersed with latencies ranging from 7 to 11 ms. In patients with hemispheric or capsular ischemic lesions "cortical" MEPs were absent when stimulating the affected hemisphere and present when stimulating the unaffected one. We suggest that the direct corticomotoneuronal projections for the masseter are mainly crossed.

Adult↗
PubMed1991

[Intraoperative angioplasty and bypass for the treatment of diffuse symptomatic coronary lesions].

After a brief description of the intraoperative angioplasty technique carried out together with direct revascularization through bypass with venous segments or with internal mammary (IMA) we hereby report the immediate and mid-term results obtained in 18 patients with this treatment. The simplicity of execution, having the possibility to operate on still heart and under the direct vision of the lesion the rareness of any complication, the fact that the coronary segment is open also during all checks done after 3 years from the treatment, and finally the considerable improvement in clinical symptomatology, lead the authors to consider this therapeutical succession possible in some selected cases, for which surgical operation is necessary.

Angioplasty, Balloon, Coronary↗
PubMed1988

Cell metabolism response to cardiopulmonary bypass in patients undergoing aorto-coronary grafting.

The main parameters of muscle acid-base, water and energy metabolism were studied in ten patients undergoing low-flux (1.5 l/min/m2), low-pressure (40 to 60 mmHg) hypothermic (26 degrees C) cardiopulmonary bypass (CPB) for aortocoronary grafting; absolute gas exchange and haemodynamic data were also measured throughout the entire CPB period. At the end of CPB a substantial preservation of water and energy metabolic indexes was found; a condition of extracellular metabolic acidosis was apparently sustained by muscle cell anaerobic glycolysis enhancement with a consequent increase of both muscle and plasma lactate content. Subnormal cell phosphocreatine levels as well as reduced bicarbonate buffer stores and decreased intracellular pH, were detected. Direct limiting effects of hypothermia on tissue O2 delivery and muscle oxidative metabolism as well as vasoconstriction and arteriovenous shunting associated with CPB procedures are likely to be involved in the above mentioned alterations of cell metabolism.

Acid-Base Equilibrium↗