Biomedical subjects

M Manca

Publications and source records attributed to M Manca.

36 records · Page 2Linked to original sources

PubMed1984

[The conduction of optic nerve fibers using different visual patterns].

The Authors have studied the behaviour of checkerboard pattern visual evoked potential (VEP) latencies by using different spatial frequency stimuli and different stimulating visual fields in order to demonstrate whether spatial frequency might constitute a parameter capable of exciting different retinal regions like different stimulus fields. According to the recent literature low spatial frequency stimuli generate VEP with latencies which are significantly shorter than high spatial frequency stimuli, making this method more reliable for the differentiation of macular and peripheral retinal fields.

Adult↗

PubMed1984

Determination of glycosylated haemoglobin by isoelectric focusing in non-linear pH gradients.

A new isoelectric focusing technique for the separation and quantitation of glycosylated haemoglobin (HbA1c) is described. By using an equimolar mixture of two separators (0.2 M beta-alanine + 0.2 M 6-aminocaproic acid) a 2-pH unit Ampholine range (pH 6-8) is transformed in a shallow, 0.6-pH unit span (pH 6.7-7.3). This brings about an increment of resolution between HbA and HbA1c by a factor of about three, thus allowing proper densitometric evaluation of the trichloroacetic acid-fixed MetHb bands by conventional gel scanners. Excellent agreement is found among microchromatography, isoelectric focusing followed by densitometry in situ, and isoelectric focusing followed by band excision, elution and spectrophotometric determination. The present method also allows full resolution between HbA1c and fetal haemoglobins (F and Fac bands).

Adult↗

PubMed1984

Pattern electroretinogram in multiple sclerosis.

The pattern electroretinogram obtained in patients affected by multiple sclerosis were compared with those in a normal population. The pattern electroretinogram amplitude in multiple sclerosis optic neuritis frequently appeared normal, but pattern electroretinogram amplitude abnormalities were found in patients suffering from recurrent multiple sclerosis optic neuritis. Pattern electroretinogram examination appears a useful method in the differential diagnosis between axonal and demyelinating optic nerve impairment.

Adult↗

PubMed1983

Static vestibulospinal influences in relation to different body tilts in man.

In this study, H-reflex testing was used to identify possible static vestibular influences on soleus alpha motoneuron excitability in man in relation to different body tilts. Ten normal adult volunteers and one labyrinthine-defective patient were tested in an experimental situation designed to minimize all afferent inputs except the vestibular ones. Each subject was fixed to a rigid platform inclinable from the horizontal (0 degree) to the vertical (90 degrees) position and vice versa. On each subject, 10 consecutive H reflexes were recorded for each of the following positions: 0 degree, 15 degrees, 30 degrees, 45 degrees, 60 degrees, 75 degrees, 90 degrees and 90 degrees, 75 degrees, 60 degrees, 45 degrees, 30 degrees, 15 degrees, 0 degree. In all normal subjects, we observed a significant increase in amplitude of the H reflex as the body was tilted from horizontal to vertical, and a significant decrease when the body was returned to the original position. These progressive changes in spinal motoneuron excitability were linearly related to the tilt angles. By contrast, no significant change in H-reflex amplitude was observed in the labyrinthine-defective patient. These results would seem to indicate that the vestibular system exerts some influences on antigravity muscles in static tilts and that these influences are behaviorally adequate to provide for the postural stability.

Adult↗

PubMed1983

The frequency of multiple sclerosis in Mediterranean Europe. An incidence and prevalence study in Barbagia, Sardinia, insular Italy.

Recent investigations on multiple sclerosis (MS) distribution in Italy, based on relatively small population groups, contradict the current thesis, derived from studies undertaken in populations exceeding 300,000, of a lower spreading of the disease in Mediterranean Europe. Intensive surveys on small populations strengthen the suggestion that Italy is a high-risk area, although MS studies based on prevalence rather than incidence could also be biased by geographic variables making prevalence unsuitable for comparing MS prevalence rates found in different years and/or zones. We report a further epidemiologic study in Barbagia, Sardinia, insular Italy, undertaken both to establish the MS incidence in the last 20 years, and to estimate a new prevalence rate. Based on 31 probable incident cases, the mean incidence per year for the years 1961-1980 was 2.9 per 100,000 (3.2 if age- and sex-standardized to the Italian population). On October 24, 1981, the prevalence per 100,000 was 65.3 (77.9 if standardized to the Italian population). These results confirm that in Barbagia, MS occurs more frequently than expected in a Mediterranean area, and give further support to the idea that MS frequency in Italy is similar to that established for most central and northern European countries.

Adolescent↗

PubMed1982

Neonatal screening of beta-thalassemias by thin layer isoelectric focusing.

As an alternative to the recently proposed screening for beta-thalassemias by isoelectric focusing (IEF) of denatured globin chains in urea-detergent gels [6], IEF of intact hemoglobins, obtained from umbilical cord blood in neonatal units, is reported here. For maximum separation, IEF should be performed in nonlinear pH gradients, in gels containing 0.2 M beta-alanine and 0.2 M 6-amino caproic acid, which flatten the pH gradient around pH 7, thus increasing the resolution between HbA and HbFac. The method can unambiguously detect homozygous and heterozygous beta-thalassemic conditions. A bimodal distribution of HbA at birth has been found: In heterozygous patients, HbA values of 9.02% (range 6.8-9.98%) have been found while in normal newborns HbA levels of 20.34% (range 11.02-30.6%) have been demonstrated.

Fetal Blood↗

PubMed1982

Uremic neuropathy: correlations between electroneurographic parameters and serum levels of parathyroid hormone and aluminum.

An electrophysiological investigation on 29 dialysis patients was performed with the aim of verifying whether serum parathyroid hormone (PTH) and aluminum (Al) levels may play a role in the pathogenesis of uremic neuropathy. All patients except 1 showed electrophysiological abnormalities. Both PTH and Al levels were found to be significantly correlated with the time on dialysis. On the contrary, the values of each single electroneurographic parameter did not show any correlation with the duration of dialysis, PTH levels and Al levels. The authors conclude that PTH and Al does not seem to play a role in the etiology of uremic neuropathy.

Adult↗

PubMed1981

The diagnostic value of H-index in S1 root compression.

The H-index was studied in 42 healthy subjects and in 20 patients showing unilateral S1 root compression. When compared to the normal subjects, all patients showed a decreased H-index, or an increased difference in H-index between the sides or both. These results indicate that both parameters are valuable in the diagnosis of S1 root impairment due to intervertebral disc protrusion.

Adult↗

PubMed1980