Biomedical subjects

G Vita

Publications and source records attributed to G Vita.

At least 19 recordsLinked to original sources

PubMed1992

A computer-assisted automatic method for myelinated nerve fiber morphometry.

This paper describes a computer-assisted automatic method developed for myelinated nerve fiber morphometry. IBAS image analysis system was used. One-micron thick sections of sural nerve were stained with p-phenylenediamine. Dark myelin sheaths, standing out against a pale background, were identified by a binary transformation of the computer-stored image. Different parameters of the fibers as well as of the axons can be measured. The automatic system allows operator-interactive manipulation, if required, to avoid inclusion of wrong histologic structures. A large spectrum of statistics facilities are available. We performed a comparison between automatic and semi-automatic analysis. Measurements resulted virtually overlapping, but time was three to four times shorter with automatic procedure. The method here described is accurate and reliable, and permits economy of time and effort.

Biopsy↗

PubMed1992

Botulinum toxin therapy: distant effects on neuromuscular transmission and autonomic nervous system.

To evaluate distant effects of botulinum toxin, single fibre electromyography on the extensor digitorum communis muscle and six tests of cardiovascular reflexes were performed in five patients injected with BoTox (Oculinum(R) 20-130 units) for craniocervical dystonia and hemifacial spasm. Patients underwent two sessions of treatment and the second time the dosage was doubled. Botulinum toxin injection induced an increase of mean jitter value above normal limits in all cases. An increase of fibre density was recorded six weeks after the treatment. Cardiovascular reflexes showed mild abnormalities in four patients. The data confirm distant effects of botulinum toxin on neuromuscular transmission and on autonomic function.

Adult↗

PubMed1992

The course of autonomic neural function in chronic uraemic patients during haemodialysis treatment.

Autonomic function was followed in 19 patients with uraemia on chronic haemodialysis treatment over a period of 18 months. A smaller group of 12 patients were studied over 56 months. The battery of cardiovascular reflex tests included R-R interval variation test, deep breathing, Valsalva manoeuvre, heart rate, and blood pressure responses to standing and sustained handgrip. Two indices of autonomic function were measured: the autonomic score, and the confidence level on Bayesian analysis. There was great variability in the course of autonomic function over the period studied, with improvement occurring in some subjects and deterioration in others. In addition some patients did not develop any abnormality. Among those patients with uraemia and normal autonomic function at the start of the study, a deterioration occurred in 33-36% in the 18-month follow-up but in 62.5% in the 56-month follow-up. As a group there was no significant change in autonomic function during follow-up, although a clear trend to deterioration was found despite chronic haemodialysis treatment.

Adult↗

PubMed1992

Morphometric analysis of sciatic nerve and its main branches in the rabbit.

In the rabbit the myelinated fibres with the largest diameter originating from the sciatic nerve distribute mainly into the peroneal nerve, even though there is no difference in the density of myelinated fibres of the representative unit between the sciatic nerve and its branches. The distribution of the myelinated fibre diameters is unimodal in the sciatic nerve, but bimodal both in the peroneal and tibial nerves. The quotient axon diameter/fiber diameter (g ratio) shows a different trend between the sciatic nerve and the branches originating from it. Except for the peroneal nerve, the increase of the axon calibre corresponds to the reduction of the relative myelin sheath thickness and therefore to the reduction of internodal distance. The results show that the sciatic nerve and its terminal branches in the rabbit have morphometrical characteristics that are peculiar and differ from those of the other rodents.

Animals↗

PubMed1991

Down-regulation of thyrotropin-releasing hormone (TRH) receptors in spinal cord after transection as revealed by quantitative autoradiography.

The autoradiographic localization of thyrotropin-releasing hormone (TRH) receptors was investigated in the rat spinal cord after transection at the level of T8-T9. The discrete distribution of [3H]-MeTRH binding was measured with a computerized image analyzer at the cervical (C6-C7) and lumbar (L2-L3) level, one week and three weeks after injury. The TRH receptor density was expressed in fmol/mg protein. There was no significant change in the density of TRH receptors below the injury site. In the cervical region, TRH receptor concentration in the dorsal gray matter did not differ from normal controls; in contrast we found a time dependent change in lamina 10 and in the ventral gray, with a significant decrease (25% and 19%, respectively) of TRH receptor binding sites one week after transection and a return to control levels by three weeks. From these data and the known increase of TRH immunoreactivity above a spinal injury, a down-regulation of spinal cord TRH receptors in response to elevated levels of TRH is suggested.

Animals↗

PubMed1991

Diagnostic potential of double contrast arthrography of the knee with the digital technique.

Experience with digital radiography applied to double contrast arthrography of the knee performed with a photostimulable phosphor plate is reported. The image processing technique used to improve the digital image is described, and some theoretical considerations are discussed. A preliminary comparison is also made between arthrographic images obtained with conventional screen-film systems and the digital system, especially in respect of the image quality and visualization of the soft tissue structures least well demonstrated with conventional arthrography.

Arthrography↗

PubMed1991

Multivariate analysis of cardiovascular reflexes applied to the diagnosis of autonomic neuropathy.

A battery of cardiovascular reflex tests is usually performed for the diagnosis of autonomic neuropathy. The tests discriminate well between normal and definitely abnormal autonomic function. However, in some patients the results are borderline and their autonomic status cannot be better defined. We performed multivariate statistical analysis of six cardiovascular autonomic tests with the aim of increasing their diagnostic efficiency. Eighty-five healthy subjects and 95 patients at risk for autonomic neuropathy were studied. Principal component analysis and two pattern recognition methods, the Bayesian technique and the SIMCA method, were applied. It was found that: (1) normal models obtained by Bayesian analysis showed very high specificity and sensitivity; (2) a battery of two tests for parasympathetic function (R-R interval variation test, deep breathing) and two tests for sympathetic function (blood pressure responses to standing and to sustained handgrip) provide an appropriate diagnostic approach, if multivariate analysis is used; (3) multivariate analysis allows a more precisely defined assessment of autonomic nervous system function in so-called borderline patients.

Adult↗

PubMed1991

Uremic autonomic dysfunction evaluated by pattern recognition analysis.

A pattern recognition analysis of six cardiovascular reflex tests was performed with the aim to increase their diagnostic efficiency. A normal model was defined by SIMCA method using log-transformed values of 85 healthy subjects. The model was tested with data from 60 patients with chronic renal failure. Specificity resulted 94% and sensitivity 96%. 55% of the uremics were recognized affected by autonomic damage. The method allowed a better definition of autonomic function in those patients defined as "borderline" on conventional evaluation of the tests. Pattern recognition analysis of autonomic tests provides a global assessment of all the tests performed. Its use should be encouraged as a diagnostic tool.

Autonomic Nervous System Diseases↗

PubMed1990

Effects of experimental spinal cord transection on substance P receptors: a quantitative autoradiography study.

The autoradiographic localisation of Substance P (SP) receptors was investigated in the rat spinal cord following cordotomy at the thoracic 8-9 level. The binding of [125I]-BH-SP was measured in discrete gray matter structures above (C6-C7 level) and below (L2-L3 level) the injury site, and expressed in fmol/mg protein. There was a statistically significant increase in SP receptor density 1 week after cordotomy in the dorsal horn and in the central canal of lumbar region, in laminae 3-4-5 and also in the ventral horn of cervical spinal cord. Elevated SP receptor density was also noted in cervical ventral horn at 3 weeks after thoracic cordotomy, whereas the increase seen at 1 week was normalized at 3 weeks everywhere else. Since SP concentration has been reported to show a similar localized increase below a spinal transection, the present results are consistent with an up-regulation of SP receptors. A similar direct relationship between SP receptors and SP content appears to occur also in the ventral horn above the injury site.

Animals↗

PubMed1990

Uraemic autonomic neuropathy.

Symptoms of uraemic autonomic neuropathy are often vague and aspecific. A correct diagnosis of autonomic dysfunction is possible by using several simple and non-invasive tests of parasympathetic and sympathetic control of the cardiovascular system. A defective regulation of the heart rate, due mostly to an afferent lesion, is more common than damage of reflex blood pressure control. The former appears isolated in 14 to 34% of uraemics on haemodialysis and combined to the latter in 18 to 26%. Contradictory results are reported about influence of intermittent haemodialysis, continuous ambulatory peritoneal dialysis and kidney transplantation on disturbed autonomic nervous system. Pathogenesis of uraemic autonomic neuropathy remains unknown and some mechanisms are only putative.

Autonomic Nervous System↗

PubMed1990

Digital radiography versus conventional radiography during excretory urography: our experience.

The authors describe a computed radiographic system employed to generate and archive digital images in intravenous urography. For each exposure the system produces two digital images: the first (left image) simulates a conventional screen-film radiograph, the second (right image); enhances some spatial frequencies and emphasizes the margins of the structures. These images can be modified in their chief parameters and then printed by a laser-printer and archived on optical disks. Four experienced radiologists evaluated digital images with regard to some chief diagnostic parameters and, in 50 patients, they compared digital images with conventional screen-film radiographs and submitted the results to statistical analysis. For some of the chosen parameters, particularly for the evaluation of renal margins before and after contrast medium injection, digital images gave statistically better results than conventional films, while, no statistically significant different was observed for the other parameters. From the results of this preliminary study digital radiography was found to be useful in intravenous urography by reducing the patient's exposition dose, by always obtaining images of good quality, and by enhancing some particular features of the standard image; on the other hand there were many unsolved problems regarding the communicating and archiving system (PACS), because of the slowness of the image transfer procedure, difficulties in data transmission and complexity of referential procedures.

Evaluation Studies as Topic↗

PubMed1990

[Digital radiography in neonatal intensive care].

The authors report their experience with the routinary use of a computerized digital radiography system in Intensive Neonatal Care department. The conventional screen-film system is replaced by photostimulable imaging plates, which are scanned during processing by a laser providing the digital image. The latter is subsequently processable on high-resolution monitors. Over a 6-month period 86 examinations were performed with this method in Intensive Neonatal Care; good technical results were obtained. The use of digital radiography in intensive neonatal care is extremely promising for it allows high-quality images to be obtained, and radiation dose and number of acquisitions to be reduced. Finally, work stations allow both selective visualization of different body structures and their magnification.

Humans↗

PubMed1990

[Traditional and digital urography compared. The authors' own experience].

A computed radiographic system for generating and archiving digital radiographic images was employed in ivp. The system produces 2 digital images per exposure: the first one simulates a conventional radiograph, while the second enhances some spatial frequencies and emphasizes the structure borders. The conventional radiographs and the digital images of 50 patients submitted to ivp were reviewed by four experienced radiologists to evaluate their comparative quality, and the results were statistically analyzed. Digital images proved to be better than conventional radiographs for some of the selected parameters, especially in the evaluation of renal edges and sometimes for calyceal opacification. As for the other parameters, no statistically significant difference was observed between conventional radiographs and digital images.

Adult↗

PubMed1989

Peripheral neuropathy in amyotrophic chorea-acanthocytosis.

We investigated involvement of the peripheral nervous system in 6 patients with amyotrophic chorea-acanthocytosis. Electromyographic and neurographic findings, and pathological changes as demonstrated by examination of biopsy specimens of muscle and sural nerve indicate that most patients had an axonal sensorimotor polyneuropathy with more pronounced involvement of the distal portion of the nerves. Results obtained in one patient raised the question of an anterior horn cell disorder.

Acanthocytes↗

PubMed1989

Prevalence survey of major neurological disorders in Sicily. Results of a pilot study.

A pilot study on the prevalence of neurological disorders in Sicily was carried out with a protocol never previously used in Italy. A screening questionnaire was administered to 1,601 subjects of a community, designed to identify patients with cerebrovascular diseases, epilepsy, extrapyramidal syndromes, peripheral neuropathies, migraine and intracranial neoplasms. Of 262 subjects who were identified as likely to be suffering from neurological illness, 248 (94.6%) were examined by a neurologist. Of these, 8.9% were found to be normal, 46.8% were suffering from non-neurological diseases, 44.3% had one or more neurological diseases (prevalence of 6.8%). This pilot study proved to be a good starting-point for a future major survey.

Adolescent↗

PubMed1989

Morphometry of in vitro systems. An image analysis of two human prostate cancer cell lines (PC3 and DU-145).

Morphometric analysis on two human prostate cancer cell lines (PC3 and DU-145) was carried out to better characterize these cells and to approach some problems concerning their polymorphism. In our hands, these cells appear to differ either in their ability to oxidize testosterone or in their androgen receptor content. Morphometric evaluation was performed by means of an Interactive Image Analysis System (IBAS 1), which computes several parameters related to the whole cell and to the nucleus. Our results clearly indicate that nuclear parameters alone may discriminate PC3 from DU-145 cells. Particularly, the Nuclear Roundness Factor appeared important, since it quantifies changes in nuclear shape. Nevertheless, the value of this parameter for "in vitro" morphometry may be overshadowed by the polymorphism common to the cultured cells. However, morphometric evaluation of PC3 and DU-145 cells is relevant to a better understanding and definition of the biologic nature of these cells, even if polymorphism, heterogeneity and genetic instability, specially of PC3, require further investigations.

Cell Nucleus↗

PubMed1989

Adult-onset centronuclear myopathy: evidence against a neurogenic pathology.

A case of sporadic adult-onset centronuclear myopathy is presented. EMG was myopathic and nerve conduction study entirely normal. Single-fiber electromyography showed a normal percentage of potential pairs with abnormal jitter, slightly increased mean jitter value, no blocking and normal fiber density. Somatosensory and motor evoked potentials were within the normal limits. While it is still a subject of debate whether centronuclear myopathy is neuropathic or myopathic in origin, our findings are against peripheral nerve and CNS involvement.

Adult↗

PubMed1989

Neuroepidemiological survey on Sicilian population. A feasibility study.

This research was designed as a pilot study in order to determine the feasibility and the reliability of a major door-to-door neuroepidemiological survey to be performed in the near future in 3 Sicilian towns with a total population of 30,000 inhabitants. 1,601 subjects were investigated by means of a questionnaire for the prevalence of stroke, epilepsy, parkinsonian syndromes, peripheral neuropathies, intracranial neoplasm and migraine. This preliminary study proved to be a good starting point, but some difficulties were identified in the questionnaire, in data collecting instruments and in diagnostic criteria.

Adolescent↗