Biomedical subjects

R Bolzani

Publications and source records attributed to R Bolzani.

At least 37 records · Page 2Linked to original sources

PubMed1992

Macular dysfunction in multiple sclerosis revealed by steady-state flicker and pattern ERGs.

Recent evidence indicates that the 2nd harmonics of steady-state (8 Hz) electroretinograms to either sinusoidal flicker (FERG) or to counterphased gratings (PERG) presented in the macular region (9 degrees) represent different subsets of generators in the inner retina. We evaluated the steady-state macular FERG and PERG 2nd harmonics (2F and 2P, respectively) in 19 normal subjects (19 eyes) and in 23 multiple sclerosis patients (44 eyes; 25 eyes with a history of clinical optic neuritis, and 19 eyes with no history of optic neuritis, subclinical eyes). The mean 2F and 2P amplitudes were significantly reduced, as compared to controls, in both subclinical and optic neuritis eyes. The 2P phase was significantly delayed, as compared to controls, in subclinical eyes, whereas 2F phase was delayed in eyes with optic neuritis. 2F was outside the 95% confidence limits (in amplitude or phase) in 11/19 subclinical eyes and in 25/25 optic neuritis eyes. 2P was outside the normal range in 12/19 subclinical eyes and in 24/25 optic neuritis eyes. These results show that FERG and PERG 2nd harmonics are significantly altered in multiple sclerosis eyes with or without a clinical history of optic neuritis. This finding suggests a dysfunction of inner macular layers which may result from direct retinal involvement or retrograde degeneration.

Adolescent↗

PubMed1992

Bioelectric brain maturation in fullterm infants and in healthy and pathological preterm infants at term post-menstrual age.

At the same post-menstrual age (39-41 weeks), EEG maturation assessed according to the Nolte and Haas method (Nolte, R. and Haas, H.G. (1978) Dev. Med. Child Neurol., 20, 167-182) was studied in 16 fullterm infants (FT), 17 healthy preterm infants (HP) and 18 pathological preterm infants (PP) affected by brain lesions (haemorrhage and/or leucomalacia). There were no significant differences in respect to EEG maturational codes, EEG types or bioelectrical age between the FT and HP groups. The preterm infants affected by brain lesions presented higher percentages of younger EEG codes (i.e. 36 weeks) in State 1 and a higher number of fluctuations between one maturation code and another in both State 1 and State 2, with respect to the HP group. Also, although the PP infants with young EEG codes did not present serious background EEG abnormalities, they did reveal minor EEG abnormalities, such as excessive asynchrony of the 'tracé alternant', lack of frontal sharp transients and monomorphic TA 'bouffees' with little activity at 2-6 c/s. However, no relationship between young EEG codes and onset-offset or duration of the states was found: young codes were often randomly distributed in successive State 1-State 2 epochs, regardless of groupings. Bioelectric age appropriate to the post-menstrual age precedes a normal development or only minor handicap at 24 months, while EEG immaturity of more than 2 weeks corresponds to later major handicaps. The prognostic value of EEG immaturity of between 1.1 and 2 weeks is uncertain.

Brain↗

PubMed1992

Dream structure in Parkinson's patients.

Dream reports of patients with Parkinson's disease (PD) were analyzed to ascertain whether cognitive deficits associated with this nonfocal brain pathology influence dream structure or dream recall. Fifteen outpatients with idiopathic PD were sampled (diagnosed from 1 to 10 years and currently in stage II or III of Hoehn and Yarh's scale); all were without psychiatric symptoms or major medical illnesses and were currently being treated with L-dopa. After an adaptation night in the sleep laboratory, each patient spent a night in which he/she was awakened at least twice in rapid eye movement sleep and asked to report dream experience. Thirteen patients were able to report at least one dream. Overall frequency of dream recall (71.4%) was fully compatible with normative data for the elderly. Multiple regression analyses showed that both the length of the dream report as story and the organization of contents into coherent episodes (analyzed using Mandler and Johnson's story grammar) varied significantly in relation to level of cognitive functioning and, in part, of language comprehension, but not in relation to age, illness duration, and dose of L-dopa.

Age Factors↗

PubMed1991

Spatial-frequency-dependent changes in the human pattern electroretinogram after acute acetyl-L-carnitine administration.

Acetyl-L-carnitine (LAC) is a neuroactive compound that is thought to be involved in cholinergic transmission. The effects of acute intravenous LAC administration (30 mg/kg) on pattern-evoked electroretinograms (P-ERGs) were evaluated in nine healthy volunteers ranging in age between 21 and 27 years. Nine age-matched, normal subjects treated with a placebo served as controls. Steady-state (8 Hz) P-ERGs recorded in response to counterphased sinusoidal gratings of variable spatial frequency (0.6-4.8 cycles/degree) were obtained before and at 20, 50 and 80 min after LAC or placebo administration. The amplitude and phase of the Fourier-analysed P-ERG second harmonic were measured. As compared with placebo-treated controls, LAC-treated subjects showed a selective P-ERG amplitude increase (Mann-Whitney rank test: P less than 0.05), which was found 80 min posttreatment at a spatial frequency of 4.8 cycles/degree. For the same stimulus a significant (P less than 0.05) P-ERG phase shortening (at 50 min after drug administration) was also found. The spatial frequencies of other stimuli did not show a significant difference between the LAC- and placebo-treated groups. These results indicate that acute LAC administration induces a spatial-frequency-dependent enhancement of the human P-ERG. This is compatible with a cholinergic excitatory effect and suggests a therapeutic role for this compound in retinal dysfunctions with selective vulnerability to medium-high spatial frequencies.

Acetylcarnitine↗

PubMed1990

Mathematical model to analyse urea synthesis following alanine infusion in control subjects and in patients with liver cirrhosis.

A three-compartment model was used to analyse the urea response to an alanine infusion in control subjects and patients with liver cirrhosis. Discriminant analysis showed a good separation between model coefficients of the two groups. A single parameter was derived, able to quantify the liver functional capacity. The method provides a useful diagnostic tool in patients with liver disease.

Alanine↗

PubMed1990

Vergence movements in comitant strabismus.

Vergence movements induced by base-out prisms were recorded, with an infrared eye tracker, for 6 patients with comitant esotropia (i.e., convergent strabismus) and anomalous retinal correspondence and for 6 normal subjects. Vergence movements of strabismic subjects were much slower and showed characteristics different from those of controls. It may be argued that vergence movements are induced by disparity and represent the motor fusion component left over in strabismus. In fact, in this study accommodative as well as proximal vergence had been ruled out. Therefore, the movements recorded can be considered the objective representation of the well-known phenomenon of prism compensation or adaptation, found in many strabismic patients.

Accommodation, Ocular↗

PubMed1989

Recording of disparity vergence in comitant esotropia.

Vergence movements induced by base-out prisms were recorded, with an infrared eye movement recording system, in 5 patients with comitant esotropia and anomalous retinal correspondence and in 5 normal volunteers. The findings support the hypothesis that vergence movements in strabismus are induced by disparity, since accommodative as well as proximal vergence had been ruled out. Vergence movements are much slower and with different characteristics in strabismic patients with respect to normals. It may be argued that vergence movements represent the motor fusion component left over in strabismus. They may be considered the objective representation of the well-known phenomenon of prism compensation or adaptation, found in many strabismic patients.

Adolescent↗

PubMed1989

Further evidence for the role of proprioception in space perception.

In this paper results are presented of errors in spatial localization found after encircling procedures for retinal detachment both in the operated and in the normal eye. Also changes in spatial localization were found in strabismus patients in which a stretch on the operated muscle was exerted after an adjustable recession. In both groups of patients a manipulation of the eye muscle was performed without inducing an eye muscle imbalance in the retinal detachment patients and without modifying the eye position in the strabismus patients in which a stretch was exerted. These data provide further evidence in favour of the role of proprioceptive information in space perception.

Humans↗

PubMed1989

Gaze and eye-contact with anorexic adolescents.

Interviews with seven anorexic female adolescents and 12 control subjects were videotaped for analysis of visual behaviour. Individual looking and mutual gaze of subject and interviewer were coded by two judges and recorded through a two-channel push-button system of time recording for 10 min of interview segments. The results indicated that anorexics looked toward the eyes of the interviewer less frequently and more briefly than controls, and that mutual gazing was less common.

Adolescent↗

PubMed1988

Role of the central field in disparity-induced vergence movements in strabismus.

Disparity-induced vergence movements (fusional movements) were analyzed in esotropic patients by calculating the time required for compensation of a prismatic correction of their angle of deviation. The effect of central and peripheral field stimulation on these movements was studied by masking the central or the peripheral field. Both the center and the periphery were effective in triggering disparity-induced vergence movements. The center even seemed to prevail over the periphery. It is concluded that in comitant esotropia motor fusion is present not only in the periphery but also in the center, if appropriately tested.

Adolescent↗

PubMed1988

Episodic pulsatile secretion of FSH, LH, prolactin, oestradiol, oestrone, and LH circadian variations in polycystic ovary syndrome.

Pulsatile secretion of LH, FSH, PRL, oestradiol and oestrone was studied in a group of 16 patients with micropolycystic ovary syndrome (PCOS) and compared with that of normal ovulatory women in the fifth to sixth day of the cycle. Hormone concentrations were measured at 10 min intervals for 8 h starting at 0930 h. In seven subjects, the study was prolonged for 24 h, with 20 min interval samples, in an attempt to evaluate the circadian rhythm of LH by cosinor analysis. Significant fluctuations occurred in the concentration of each hormone. Values shown are mean +/- SD. PCOS subjects had high LH mean values (27.9 +/- 5.9 IU/l) (P less than 0.005). LH pulse amplitude was higher than controls (11.6 +/- 3.7 IU/l versus 5.2 +/- 1.8 IU/l; P less than 0.005) while no consistent changes in frequency or interpulse interval (62.0 +/- 10.7 min versus 65.8 +/- 19.2 min; P = NS) were found. A mean of 4.8 +/- 1.2 pulses of FSH occurred in 8 h and the mean pulse amplitude was 2.68 +/- 1.11 with no differences from controls. All patients were normoprolactinaemic. A mean of 5.5 +/- 1.9 pulses occurred in 8 h, the interpulse interval was 76.1 +/- 14.4 min and the amplitude was 2.87 +/- 0.76 ng/ml and there were no significant differences from controls; 75% of PRL pulses showed a temporal relationship with LH pulses. Oestrone mean basal values were higher in PCOS (47.2 +/- 12.5 pg/ml) than controls (32.0 +/- 9.9 pg/ml; P less than 0.02), while no differences were observed as regards oestradiol. Oestradiol pulse amplitude was nearly the same as oestrone (43.6 +/- 18.8 pg/ml and 37.7 +/- 16.1 pg/ml, respectively); 6.0 +/- 2.2 pulses and 6.0 +/- 1.6 pulses occurred in 8 h with an interpulse interval of 81.1 +/- 27.1 min and 71.8 +/- 11.1 min, respectively. Sixty-five per cent of LH pulses were followed by an oestradiol and oestrone peak. The mean time of the appearance was 17 +/- 15 min and 25 +/- 23 min, respectively. In the PCOS group a consistent 24 h rhythm in mean plasma LH levels was found with the highest hormone values at 1720 h (P less than 0.05) unrelated to apparent sleep and different from that of adult women. Pulse frequency showed a significant slowing during the night with the longest interpulse interval at 0327 h (P less than 0.03) while no significant periodicity was observed in LH pulse amplitude.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗

PubMed1987

Distance judgement in comitant strabismus with anomalous retinal correspondence.

Judgement of distances was evaluated in 19 patients with comitant esotropia and without appreciable stereopsis. In nine patients anomalous retinal correspondence (ARC) was present at Bagolini's striated glasses. In the remaining patients there was suppression with the same test. Distance judgement of strabismics with ARC does not differ statistically from that one of normals. Significantly different results were found in strabismics with suppression. It is concluded that ARC is not only an anti-diplopic mechanism, but provides the patients with useful clues in their daily life.

Adolescent↗

PubMed1987

Circadian variations of luteinizing hormone can have two different profiles in adolescent anovulation.

The circadian profile of plasma LH concentrations was investigated in 12 healthy anovulatory adolescent women by drawing blood samples every 20 min for 24 h during the early follicular phase. Plasma 17 beta-estradiol, testosterone, and androstenedione levels were measured in the first sample. Ovarian size was measured by ultrasound. According to their mean plasma LH levels, the adolescents were divided into two groups, those with a high plasma LH level (2 Sd or greater than the mean adult value) and those with a normal plasma LH level. The mean plasma estradiol (P less than 0.001) and testosterone (P less than 0.05) levels were higher in the women with high plasma LH levels compared to those in women with normal plasma LH levels. The LH pulse amplitude was greater (P less than 0.05) and the interpulse interval shorter (P less than 0.025) in the high LH group compared to those in the normal LH group. A 24-h periodicity with the highest plasma LH levels and the greatest pulse amplitude in the afternoon was found in high LH group. In the normal LH group, the highest plasma LH levels and greatest pulse amplitude occurred in the first hours of the morning. An accentuated 24-h LH periodicity is typical of puberty, but disappears in adulthood. We have recorded the persistence of pronounced LH circadian changes in anovulatory adolescent women which might be a marker of a continuing maturational process. Furthermore, LH circadian changes have opposing profiles according to the mean LH values, suggesting the presence of different central nervous system pubertal programs.

Adolescent↗

PubMed1986

Surgical correction of convergent strabismus: its relationship to prism compensation.

Esotropic patients whose angle of strabismus has been corrected by prisms frequently increase their angle deviation to compensate for the prismatic correction. This sensorio-motorial reaction to prism correction has been given the name of anomalous movements (a.m.). Quantification of a.m. has been made according to the amount of prisms that an esotropic patient is capable of compensating for (progressive prism compensation test--p.p. test). Some esodeviation does not compensate for any prisms at all since a.m. have not yet developed. Other cases compensate for as much as 40 or 60 prism diopters and more of over-correction of the angle deviation and they therefore have powerful a.m. The interference of these innervational forces acting on the medial recti to corrective surgery has been studied in 126 operated esotropic patients. A significant decrease from the expected surgical result (p less than 0.001) has been found in patients having powerful a.m., as can be judged by the p.p. test. It is believed that a.m. are an important drawback contributing to vitiate any formula on the amount of muscle surgery to be performed in patients having no possibilities of restoring normal binocular vision. Practical advice on how to eliminate this drawback and theoretical reasoning on the significance of a.m. are offered.

Adaptation, Physiological↗

PubMed1986

Abnormal spatial localization in patients with herpes zoster ophthalmicus. Evidence for the presence of proprioceptive information.

Patients with herpes zoster of the ophthalmic branch of the trigeminal nerve and normal ocular motility were examined. They were asked to point to targets without the sight of their own hand. Significant errors were found on the affected side. Proprioceptive information of the extraocular muscles is assumed to travel in the trigeminal nerve, and these results thus suggest the existence of peripheral afferent signals influencing eye-hand coordination.

Herpes Zoster Ophthalmicus↗

PubMed1986

Abnormal blood rheology in retinal vein occlusion. A preliminary report.

Hemorheological factors were studied in 34 patients affected by retinal vein occlusion (RVO) and in 25 control subjects. Whole blood viscosity, plasma viscosity, fibrinogen and hematocrit were increased in RVO patients compared with controls. Whole-blood filterability was reduced in RVO patients compared with controls. However, when evaluating the type of capillaropathy at fluorescein angiography, blood viscosity and plasma viscosity were altered in both patients with and without evidence of capillary nonperfusion. Reduction of blood filterability showed statistical significance only in patients with capillary nonperfusion. This finding suggests that reduced whole-blood filterability might be a causal factor in the development of capillary nonperfusion in RVO patients.

Adult↗

PubMed1985

[Hemorheological changes in retinal vein occlusions].

Some hemorheological factors were studied in 34 patients affected by retinal vein occlusion (RVO) and in 25 healthy control subjects. Whole blood viscosity, plasma viscosity, fibrinogen and hematocrit were increased in RVO patients compared with controls. Erythrocyte filterability was reduced in RVO patients compared with controls. However, when evaluating the type of capillaropathy at fluorescein angiography, blood viscosity and plasma viscosity were altered both in patients with and without evidence of capillary non-perfusion. Reduction of red cell filterability showed statistical significance only in patients with capillary non-perfusion. This finding suggests that reduced erythrocyte filterability might be a causal factor in the development of capillary non-perfusion in RVO patients.

Adult↗

PubMed1984

Binocular visual perception in strabismics studied by means of visual evoked responses.

Ten normal subjects and 14 patients with comitant esotropia were examined by means of pattern visual evoked responses (VER) under monocular and binocular viewing conditions. When both eyes were stimulated together a VER summation was noted both in normals and in strabismics with small-angle deviation and anomalous retinal correspondence (ARC). This is considered as an objective proof of binocularity. Patients with large-angle strabismus and/or suppression of the image of the deviated eye did not show summation. The significance of summation and its relationship with binocular vision was analyzed by recording binocular VER in normals in which diplopia was artificially induced and in strabismics who spontaneously exhibited double vision. A simple way for differentiating normals from strabismics by means of VERs is presented, considering that the presence or absence of summation per se does not achieve this result. This method is based on the anteposition in front of the fixing eye of neutral filters of increasing density. Summation disappears in strabismics with much weaker filters than in normals (0.5 versus 1.6 log. unit).

Electrophysiology↗