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Biomedical subjects

D Buffa

Publications and source records attributed to D Buffa.

At least 19 recordsLinked to original sources
PubMed2006

Use of marginal donors in kidney transplantation: our experience.

The use of elderly donors has been advocated to expand the organ donor pool because of increased needs and the organ shortage. The aim of this study was to analyze whether the use of elderly donors and marginal kidneys affected the outcome of renal transplantations. Herein we presented data on 126 kidney transplantations performed from January 1996 to September 2003 using 32 marginal donors (group A) and 94 ideal donors (group B). We analyzed the medical and surgical complications and the graft survivals at a median follow-up of 18 months. Medical and surgical complications occurred in 22% and 5% versus 7% and 4% in groups A and B, respectively. The mean cold ischemia time and the mean age were greater for patients undergoing kidney transplantations from marginal donors. No differences were observed in graft survival in groups A and B. In conclusion, our data suggested that with an appropriate strategy and a correct selection of patients, marginal kidneys can be safely used to decrease the gap between demand and supply.

Cadaver↗
PubMed2002

A transcranial magnetic stimulation study evaluating methylprednisolone treatment in multiple sclerosis.

OBJECTIVE: To investigate the efficacy of two different high doses of intravenous methylprednisolone (IVMP) during Multiple Sclerosis (MS) relapses. BACKGROUND: Transcranial Magnetic Stimulation (TMS) is the most sensitive neurophysiological ascertainment to quantify motor disability, to follow the recovery from an MS relapse, and to detect the response to treatment. DESIGN AND METHOD: Twenty-four clinically definite relapsing - remitting MS patients presenting a relapse were randomly assigned to a treatment for 5 days with IVMP 1 or 2 g/day. The response to treatment of each patient was evaluated through Expanded Disability Status Scale (EDSS), Medical Research Council (MRC) score, and TMS by means of motor evoked potential (MEP) parameters. RESULTS: Motor threshold (MT), central motor conduction time (CMCT) and MRC showed a higher improvement with the highest dose of IVMP. Silent period and EDSS improved with both treatments. CONCLUSION: The dose of 2 g/day of IVMP is more effective in MS relapse.

Adult↗
PubMed2001

rTMS of the unaffected hemisphere transiently reduces contralesional visuospatial hemineglect.

To verify the role of interhemispheric influences on manifestations of neglect, the authors investigated the effects of a transient repetitive transcranial magnetic stimulation (rTMS)-induced disruption of the unaffected hemisphere on contralesional visuospatial neglect in two left- and five right-brain-damaged patients. Parietal rTMS of the unaffected hemisphere during the execution of a computerized task of bisected line's length judgment transiently decreased the magnitude of neglect as expressed in the number of errors.

Aged↗
PubMed2001

Modulation of intracortical inhibition induced by low- and high-frequency repetitive transcranial magnetic stimulation.

We studied the changes of duration of subsequent silent periods (SPs) during repetitive magnetic stimulation (rTMS) trains of ten stimuli delivered at low (1 Hz) and high (7 Hz) frequencies. The effects at different intensities of stimulation (motor threshold, MT, 115% and 130% above the MT) were also evaluated. rTMS was performed in eight healthy subjects with a figure-of-eight coil placed over the hand motor area. The SP was recorded from abductor pollicis brevis (APB) muscle during a voluntary contraction of 30% of maximum effort. rTMS at 1-Hz frequency progressively decreased the duration of SP, whereas an alternating pattern of smaller and larger values was observed during trains at 7-Hz frequency and higher stimulus intensity. The findings show that rTMS changes the duration of cortical SPs; the effect is probably due to the modulation of intracortical inhibitory interneurons depending on the frequency and intensity of stimulation.

Adult↗
PubMed2000

Contralateral neglect induced by right posterior parietal rTMS in healthy subjects.

We applied repetitive transcranial magnetic stimulation (rTMS) in order to induce interference on visuo-spatial perception in 11 healthy subjects. Subjects performed a visuo-spatial task requiring judgements about the symmetry of prebisected lines. Visual stimuli consisted of symmetrically or asymmetrically transected lines, tachystoscopically presented for 50 ms on a computer-monitor. Performance was examined in basal condition and during rTMS trains of 10 stimuli at 25 Hz, delivered through a focal coil over right or left posterior parietal cortex (P5 and P6 sites) and triggered synchronously with visual stimulus. Randomly intermixed sham rTMS trains were employed to control for non-specific effects. Right parietal rTMS induced a significant rightward bias in symmetry judgements as compared with basal and sham rTMS conditions. No differences emerged between other conditions.

Adult↗
PubMed2000

Is season of birth associated with multiple sclerosis?

OBJECTIVE: To compare the monthly distribution of multiple sclerosis (MS) patients' births with that of the Sicilian population. BACKGROUND: Studies on the association between season of birth and risk of MS are scanty and controversial. DESIGN AND METHODS: Archives of the Institute of Neuropsychiatry of the Universities of Palermo and Catania were searched up to 1995 for definite MS patients (McDonald & Halliday criteria). The monthly distribution of MS patients' births (N= 965) was compared with that of the Sicilian population (N= 5,608,307). RESULTS: The distribution of births among MS patients compared with the general population was not different when tested by the chi2 statistic (P> 0.25). The Hewitt's non-parametric test for seasonality showed an excess of births between June and November among MS patients (P=0.004). CONCLUSION: A different pattern of MS patients' births is observed in Sicily and in Northern countries.

Age Factors↗
PubMed1999

Reorganization of cortical motor area in prior polio patients.

OBJECTIVE: Focal transcranial magnetic stimulation (TMS) was used to study the motor maps of upper limb muscles in 7 adult patients with a history of paralytic poliomyelitis. The aim of the study was to verify the potential for long-term cortical reorganization of a selective peripheral motor neuron lesion suffered early in life. METHODS: Patient selection was based on the prevalent involvement of proximal muscles in only one of the upper limbs. Motor evoked potentials (MEPs) were recorded from deltoid and abductor pollicis brevis (APB) muscles. Each muscle map was characterized by area (no. of excitable positions), volume (the sum of MEP amplitudes at all scalp positions), maximal amplitude (the highest MEP recorded). RESULTS: In the patients, the mean area, volume and maximal amplitude were significantly greater in affected vs. contralateral deltoid (P<0.05) and vs. controls (P<0.01). No significant differences were found in APB map parameters. The APB/deltoid ratio for area was lower in the affected compared with the unaffected side and controls (P = 0.06). Cortical reorganization was not significantly correlated with motor performance. CONCLUSION: These findings are consistent with a rearrangement in human motor pathways targeting muscles affected by a lower motor neuron lesion.

Adult↗
PubMed1999

Multievoked potentials in type I diabetic patients: one year follow-up study.

A neurophysiological (SEP, VEP) follow-up study was carried out in 30 diabetic patients with type I diabetes mellitus of ten or more years duration. This in order to investigate whether one year of improved glucoregulation may influence the progression of central damage. In our series, patients showed a significant decrement of HbA1C levels (p < 0.05) in the one-year follow-up. In the same period the frequency of SEP and VEP abnormalities varied from 10/30 (33%) to 16/30 (53%) and from 8/30 (26%) to 5/30 (16%) respectively. This finding would suggest that prevailing glycaemic control would be a major determinant for the outcome of VEP measurements. SEP alterations, in contrast, tend to progress in a 12 months period despite a considerable improvement in glycaemic control. However, by dividing patients in two groups according mean one year HbA1C less than 8% and more than 8%, the latter group only showed a significant increasing of absolute latencies of each median and tibial SEP components. Our results suggest that VEP abnormalities are still reversible in diabetic patients with improved metabolic control. The acquired abnormalities of somatosensory pathways persist longer, but a strict glycaemic control may influence and retard the progression of central conduction involvement.

Adolescent↗
PubMed1999

Cell counting and three-dimensional reconstruction to identify a cellular wave in human spermatogenesis.

OBJECTIVE: To collect quantitative and stereologic data on the main cell types represented in the seminiferous tubule in order to produce a three-dimensional representation of the morphologic events of normal cell production and maturation. STUDY DESIGN: Three-dimensional reconstruction and differential cell counting were performed on serial sections of normal testicular tissue from normal young men through image analysis and computer-based rendering. RESULTS: Peculiar periodicity in the total number of tubular cells considered along the sequence of serial sections was recognized. Also, consensual periodicity pertaining to each cell type was recognized. Adjacent high cellularity and low cellularity segments included a fairly constant mixture of cell types considered. CONCLUSION: A newly defined cellular wave, composed of regular alternations of high and low cellularity segments, was identified in the normal human seminiferous tubule.

Adult↗
PubMed1998

Neurophysiological and radiological findings in myotonic dystrophy patients.

Somatosensory evoked potentials (SEPs) and brainstem auditory evoked potentials (BAEPs) were recorded in 10 patients with myotonic dystrophy and in 20 sex and age-matched healthy controls. In all patients a brain MRI examination was also performed. In our results, the significantly longer absolute peak latencies of the SEPs and the abnormal increasing of the later components of the BAEPs suggest an involvement of the afferent sensory and central auditory pathways. Brain MRI showed white matter hyperintense lesions (WMHL) in eight patients (80%). No correlations were found between individual abnormal electrophysiological parameters or severity of WMHL and age, age at onset, disease duration or muscular impairment. The total number (SEP + BAEP) of electrophysiological abnormalities significantly correlated with muscular impairment (p < 0.05) and MRI changes (p < 0.005), suggesting a strict pathogenetic linkage between muscular and nervous system alterations in this disease.

Journal Article↗
PubMed1997

Magnetic stimulation study in patients with myotonic dystrophy.

To further define motor nervous system alterations in myotonic dystrophy (MD), motor potentials to transcranial and cervical magnetic stimulation (MEPs) were recorded from the right abductor pollicis brevis muscle in 10 patients with MD and in 10 healthy controls. Cortical and cervical latencies, central motor conduction time (CMCT), stimulus threshold intensity and cortical MEP amplitudes expressed both as absolute values and as %M were analysed. MEP cervical latency, absolute or relative amplitude and excitability threshold did not significantly differ in patients and controls. The mean cortical motor latency and CMCT were significantly prolonged in MD patients with respect to normal subjects. Moreover, CMCTs were found to be significantly related to stimulus threshold intensity (P = 0.03) and only marginally related to absolute cortical amplitude (P = 0.06). These findings are indicative of a central motor delay, also related to decreased excitability of motor neurons, in patients with MD. No correlations were found between individual neurophysiological parameters and age, duration of disease and clinical impairment. Our results suggest that magnetic stimulation studies can detect subclinical dysfunctions of the central motor system in MD patients, as one of the multisystemic manifestations of the disease, rather independent of the primitive muscle damage.

Adolescent↗
PubMed1997

Evoked potential study in facio-scapulo-humeral muscular dystrophy.

Nerve conduction velocities (NCVs), somatosensory (SEPs) and auditory evoked potentials (BAEPs) were recorded in 9 patients with facio-scapulo-humeral dystrophy (FSHD) and in 20 age-matched controls. In FSHD patients a significant increase of the nerve distal sensory latencies and of the absolute SEP latencies revealed a subclinical involvement of the afferent sensory pathways, as well as the abnormal slowing of the later components of the BAEPs, pointed to a central auditory dysfunction. Moreover all patients underwent brain MRI that showed the presence of white matter hyperintense lesions in 4 of them (44%). No correlations were found between individual or total number of SEP and BAEP abnormal electrophysiological parameters and severity of WMHL, age, age at onset, duration of the disease or muscular impairment. These findings make the interpretation and pathophysiology of the nervous damage in FSHD rather uncertain. More studies are required to better define the aspects of neurogenic involvement in this type of muscular dystrophy.

Adult↗
PubMed1996

Somatosensory and visual evoked potentials study in young insulin-dependent diabetic patients.

To evaluate central nervous system involvement in diabetes, somatosensory (SEPs) and visual (VEPs) evoked potentials were investigated in a group of 35 patients and 20 sex, age-matched controls. In order to avoid methodological biases due to different type and duration of disease, we studied an omogeneous group of young insulin-dependent diabetics with ten or more year duration of disease. In our results VEP and SEP parameters were found abnormal in 10 (28%) patients, all of whom presenting clear signs of peripheral neuropathy. In diabetic patients median and tibial SEPs showed significant increase in absolute latency mean values of several components except interpeak intervals, as well as mean P 100 latencies were significantly increased in both eyes at 15' check size stimulation pattern. VEP and SEP components were not generally significantly associated with the indices of peripheral function. In contrast, in diabetics significant correlations were found between P 100 latencies and median SEP parameters including interpeak intervals. No major associations related VEP and SEP latencies to duration of diabetes and prevailing glycaemic control. In conclusion the central nervous system involvement in young insulin-dependent diabetics, even though diffusely present, seems unequivocally concomitant to peripheral conduction impairment.

Adolescent↗
PubMed1987

Short-chain fatty acids produced by anaerobic bacteria alter the physiological responses of human neutrophils to chemotactic peptide.

The effect of some short-chain fatty acids (SCFA) produced by anaerobic bacteria, namely acetic, propionic, isobutyric, butyric, isovaleric and succinic acids, on production of light and release of lysozyme by human neutrophils exposed to chemotactic peptide fMet-Leu-Phe was investigated. A short period of incubation of neutrophils with SCFA led to marked inhibition of both granulocytic chemiluminescence and degranulation (P less than 0.001). Ultrastructural studies of neutrophils, incubated with concentrations of SCFA inhibiting the chemotactic response, chemiluminescence and release of lysozyme (30 mmol/l), effected alterations in cellular morphology with formation of protrusions of varying shape. The data reported indicate that SCFA might be regarded as important pathogenicity factors. The observed effect on neutrophils could also partially explain the ability of anaerobes to inhibit their own phagocytosis and killing as well as that of the aerobic species present in mixed infections.

Bacteria, Anaerobic↗
PubMed1986

[Changes in the response time of anti-HBc IgM in a hepatitis B case load. Diagnostic implications].

Anti-HBc IgM were determined in 46 patients whose serum was positive for hepatitis B surface antigen (HBsAg). All sera were tested from 1:4000 up to 1:8128000 dilution with a radioimmunometric assay. Anti-HBc IgM persisted at detectable level for up 15 months from acute infection in more than 50% of the patients. High levels of anti-HBc IgM are seen only in the acute phase but it is difficult to establish a cut-off dilution displaying diagnostic value between current and remote infection. Anti-HBc IgM are always detectable in acute hepatitis B virus (HBV) so that the absence of HBc IgM in acute hepatitis with positive HBsAg allows to discard HBV as the causative agent and to suspect a non-B hepatitis (A, delta, NANB). On the contrary the presence of anti-HBc IgM in detectable amounts in patients with acute hepatitis and negative HBsAg makes possible the diagnosis of acute B virus hepatitis.

Acute Disease↗