Biomedical subjects

A Grasso

Publications and source records attributed to A Grasso.

At least 19 recordsLinked to original sources

PubMed1992

Alpha-latrotoxin: preparation and effects on calcium fluxes.

A toxin that causes a massive presynaptic activation of transmitter release from nerve terminals is alpha-latrotoxin, isolated from Latrodectus tredecimguttatus spider venom. This toxin has been highly purified, utilizing as a biological assay a toxin-dependent increase in 45Ca(2+)-accumulation by PC12 cells. The purification protocol includes an ion-exchange step and a gel-filtration column, by fast-flow liquid chromatography. The resulting toxin is a polypeptide of about 125 kDa in molecular mass. At nmol concentrations it specifically activates calcium influx and transmitter secretion after interacting with neuronal acceptors of the presynaptic membrane. The inhibitory effect of trivalent ions (which may develop as degradation product of 45Ca2+) on toxin-dependent calcium accumulation by PC12 cells is described. The results obtained suggest that calcium fluxes directly involved in the neurosecretory event, may occur through newly formed toxin-dependent channels.

Animals↗

PubMed1992

[The incidence and role of the os acromiale in the acromiohumeral impingement syndrome].

Os acromiale (an apparently supernumerary bone) corresponds to persistence of the lateral end of acromion ossification nucleus over 18 years of age. Os acromiale is articulated with the clavicle and the base of acromion; its incidence is high and often bilateral. A rarer variant is secondary os acromiale, lying between acromion and great humeral tuberosity. Both variants predispose to the onset of pain due to acromiohumeral impingement. Rotator cuff tears are frequently associated due to direct injury to subacromial compartment structures and to overtraction of acromiocoracoid ligament following functional overuse. Three hundred and ninety-eight patients were examined (313 males and 85 females, aged 12 to 71 years): 265 of them underwent conventional radiography with specific projections for the shoulder and 133 underwent CT. Dysplasia was observed in 9.55% of cases (38 patients), which is in agreement with reports by other authors. CT demonstrates the presence of os acromiale better than specific radiographic projections, without requiring painful patient positioning. Axial CT scans allow the depiction of subacromial compartment structures that cannot be demonstrated by US. The evident and frequent association of arthrotic-degenerative acromioclavicular alterations even after os acromiale assimilation confirms the close relationship of the latter bone to rotator cuff conditions, especially to rotator cuff tears. In our opinion, the correct description of this finding has high prognostic value in the subjects likely to experience functional shoulder overuse and allows the correct etiopathogenesis of pain. Therefore CT, which is an elective imaging method especially suited to demonstrate calcium-density structures, thanks to its high spatial and contrast resolution, can be used concurrently with MR imaging because it is less expensive and more easily available.

Acromioclavicular Joint↗

PubMed1992

Spinal cord injury: some epidemiological data. A review of 233 cases.

Two hundred thirty-three consecutive cases of traumatic para- and tetraplegia admitted to a department of Neurosurgery in Naples within ten years were reviewed and categorized according to etiology, level of lesion and clinical features. The age of the patients at the time of injury varied from 7 to 74 years with a mean age of 37.1 +/- 17.1 (male mean age = 35.8 +/- 16.7; female mean age = 41.5 +/- 18.2). The male/female sex ratio was 4.8. Of these patients 66 were paraplegic and 167 were tetraplegic. The analysis of the various causes of the spinal cord injury showed that the occupational activities take the first place (32.2%); injuries in recreational activities and road accidents accounted for the majority of the remaining cases.

Adolescent↗

PubMed1991

Familial congenital brachial palsy.

Eight relatives in a Sicilian family, including a sibship of 5, were affected with severe unilateral congenital brachial palsy (CBP) in a pattern suggesting autosomal dominant inheritance with reduced penetrance (6 cases affected on the right, 2 on the left). X-linked inheritance with expression in heterozygous females cannot be excluded.

Arm↗

PubMed1991

Effects of beta-adrenoreceptor antagonists on cerebral blood flow of cirrhotic patients with portal hypertension.

The current study evaluated the effect of two beta adrenergic-blocking agents, propranolol (PRP) and atenolol (ATN), versus placebo on cerebral blood flow (CBF) of three homogeneous groups of cirrhotic patients with portal hypertension. CBF was measured by the noninvasive 133-Xenon inhalation method at rest and 1 hour after a single oral dose of PRP (40 mg), or ATN (100 mg), or placebo. Blood pressure and heart rate (HR) were measured at the beginning of each examination, and end-tidal pCO2(PeCO2) was monitored. The HR decreased significantly in both the PRP and ATN groups (P less than .01), whereas no changes were recorded for both PeCO2 and mean arterial blood pressure (MABP). The comparisons of the CBF differences among groups (ANOVA with the significance levels adjusted by the Bonferroni's correction) showed a significant increase in CBF after ATN as compared with both placebo (P less than .02) and PRP (P less than .01), whereas no significant differences were seen after PRP as compared with placebo. Our results confirm that PRP does not significantly affect CBF, whereas ATN induces an increase in CBF, although the underlying mechanism is difficult to explain.

Adrenergic beta-Antagonists↗

PubMed1991

[A controlled clinical experiment "within subjects" with heparan sulfate in intermittent claudication].

An experimental clinical trial was carried out using heparan sulphate in order to assess its antithrombophilic, profibrinolytic and possibly hemorheological characteristics. Twenty patients with stage 2 obliterating arteriopathy of the lower limbs were enrolled in the study. Patients were fully informed regarding the experimental protocol: a controlled, crossover and double-blind study. The population sample included 20 subjects, male and female, mean age 60.9 years who received heparan sulphate at a dose of 200 mg/die (one 100 mg tablet twice a day): treatment continued for 120 days (60 days of treatment with heparan sulphate and 60 days with placebo). The results obtained were in favour of medical therapy which was significantly more effective than placebo in relation to a number of parameters: compared to basal values, walking parameters were improved, recovery times were more rapid and gait was longer. Significant changes in hemocoagulative and hemorheological parameters were also observed (euglobulin lysis time, fibrin degradation products, erythrocytic filtration, hematic viscosity) and their positive trend may account for peripheral hematic perfusion, as shown by photoplethysmographic tests, velocimetric tests and the modification of the Windsor index. Therapeutic efficacy and the good tolerance (one case of gastralgia, two of pyrosis) as well as broad safety margins offered by the drug justify the use of heparan sulphate in all clinical conditions characterized by thrombophilia and local ischemia, above all those which require long-term treatment.

Adult↗

PubMed1991

Archaic reflexes in normal elderly people.

The AA. have considered the incidence of some primitive reflexes in the "normal" old people. 120 subjects have been examined (60 M and 60 F) between the 70 to 90 age-group. The patients have been selected on the basis of the absence of neurologic disorders, psychiatric and systematic or dysmetabolic diseases. All the subjects undergo a standard neurologic examination. Results show that the examined reflexes can be present in normal old people. These signs seem to be related to the physiological ageing of the nervous system.

Aged↗

PubMed1991

[Memory. Cognitive, anatomic and pathologic models].

This overview deals with the neuropsychology of memory. First cognitive models proposed for primary and secondary memory are reported, particularly the working memory theory and episodic/semantic distinction are discussed. Briefly the modern point of view about the anatomical bases of memory functions are reported with stressing above all the role of limbic structures. Lastly the pathology of both primary and secondary memory is dealt with, trying to abstract the clinical features of different syndromes.

Brain↗

PubMed1991

An adjustment method for spinal cord stimulators based on simplified gait analysis (1).

The use of electrical stimulators, for pain relief, spasticity reduction, and other applications, is greatly increasing; the programming facilities of the new devices extend the application range and allow to reduce the manufacturing costs. On the other side it is necessary to define methodologies and protocols for a custom setting of these devices. This work, although for only one patient, is a proposal for a methodology, based on a simplified gait analysis, for the adjustment of a spinal cord electrical stimulator.

Electric Stimulation Therapy↗

PubMed1990

Immunocytological localization by monoclonal antibodies of alpha-latrotoxin in the venom gland of the spider Latrodectus tredecimguttatus.

Monoclonal antibodies, raised against alpha-latrotoxin, have been used on serial sections of the venom glands with localization by indirect immunofluorescence. Colloidal gold immunovisualization and electron microscopy were used in order to localize the structure of the cells that synthesize and store the toxin. The antibodies were able to recognize the native toxin revealing its presence mainly in the 'replacement cell' layer, a layer of cells close to the muscular sheath of the gland. These cells apparently replace the disintegrated epithelial cells at the end of the holocrine cycle. Gold grains were predominantly observed around the free ribosomes and the secretion droplets of the 'replacement cells'.

Animals↗

PubMed1990

Alpha-latrotoxin triggers an increase of ionized calcium in Xenopus oocytes injected with rat brain mRNA.

When Xenopus oocytes are injected with rat brain mRNA, they acquire the ability to respond to bath applied alpha-latrotoxin. This spider venom toxin is normally highly selective for nerve endings, where its binding is associated with a high-frequency, quantal discharge of neurotransmitter. By 'transplanting' toxin acceptor sites to Xenopus oocytes, we have observed both a toxin-mediated rise in cellular ionized Ca along with the triggering of a calcium-dependent chloride channel in these cells. This approach may contribute both to a better understanding of the mechanism of action of this toxin and to efforts to clone the cDNA for this binding site.

Animals↗

PubMed1990

Motor nerve terminal restoration after focal destruction in young and old mice.

Regeneration of soleus motor nerve terminals after focal destruction by black widow spider venom (BWSV) or its active factor alpha-latrotoxin (LTx) was compared in young and old CBF-1 mice. The object was to determine whether previously reported delayed regeneration after nerve injury in old rodents was due to altered removal of debris, or delay or aberrancy in structural or functional restoration of the neuromuscular junction. In addition, the use of a new fluorescent technique permitted for the first time quantitation of the accuracy of early nerve terminal regeneration in mammalian muscle. Immunohistochemical and electron micrographic studies showed no age difference in destruction of terminals and removal of debris 2 days after toxin application. The indirect twitch and structural reinnervation (measured with flourescent techniques) returned to an equal extent in young and old mice beginning at 3 days after LTx treatment. BWSV (as opposed to LTx) delayed regeneration 1 day in young but not in old mice. On the first day of reinnervation, there was perisynaptic outgrowth in both young and old mice, although in the latter, there was a higher incidence of aberrant outgrowth. The relation between return of twitch strength and recovery of nerve terminal area (measured in teased zinc iodide-stained preparations) showed no age dependency. We conclude that factors cited to explain altered reactive sprouting in the aging CNS do not apply to regeneration of peripheral motor nerve terminals. However, it is possible that the aberrant regrowth observed at the neuromuscular junction in old mice will pertain to the aging CNS. Altered axonal rather than nerve terminal regeneration is the likely source of delayed peripheral nerve regeneration in old animals.

Aging↗

PubMed1990

[Sports pathology of the shoulder: its imaging diagnosis].

Success and diffusion of various sports have produced more frequent capsular-ligamentous lesions of the shoulder. Diagnosis up to now has relied on traditional radiology using many projections to demonstrate extremity lesions and their congruences; however for capsular-ligamentous lesions, arthrography in used successfully. Since the last few years new investigating methods are used (U.S., C.T., M.N.R.). After examining benefits of each diagnosing method compared to traditional radiology, the authors conclude that traditional radiology still has a pre-eminent role in diagnosing sports pathology of the shoulder.

Arthrography↗

PubMed1990

[The physiopathology of supranuclear structures in oculomotor disorders].

Several structures, located at different levels in the Central Nervous System (CNS), collaborate to the control and realization of ocular movements (O.M.) Therefore, alterations of oculomotricity, of varying degree and of different kinds, may be found in a lot of diseases of the CNS. The study of O.M., expecially when carried out by means of specific techniques such as electro-oculography, may represent an useful tool in the diagnosis (both from a topographic and an etiological standpoint) and in the follow-up of patients, possibly also allowing a precise evaluation of therapy effectiveness. In this review the Authors briefly examine the role of the supranuclear structures mostly involved in the control and in the execution of oculomotricity and the characteristics of the different types of O.M. (rapid and slow, vergence movements). Successively, they analyze the semeiological features of supra-nuclear disturbances of O.M., describing alterations of saccadic movements (slowing, dysmetria) and of smooth pursuit, fixation instability (square waves, flutter, opsoclonus, nystagmus,...) and other alterations of O.M. (ocular bobbing, see-saw nystagmus, skew deviation,...). Successively, disturbances of O.M. are analyzed in relation to their topodiagnostic significance, describing oculomotor involvements due to focal lesions of different areas of CNS (frontal cortex, parieto-occipital cortex, basal ganglia, cerebellum, brainstem) and particular syndromes (Foville syndromes, locked-in syndrome, Parinaud syndrome, anterior internuclear ophthalmoplegia, "one and a half" syndrome, Balint syndrome,...). Finally, particular attention is drawn to the oculomotor disturbances observed in degenerative cerebellar and multisystemic diseases, and several abnormal "oculomotor patterns", which seem to be specifically related to particular diseases, are described. In particular, the oculomotor patterns of Steele-Richardson-Olszewsky disease (slowing and hypometria of horizontal saccades, loss of upward saccades with preservation of reflex movements) and of Friedreich ataxia (fixation instability mostly due to the occurrence of square waves, saccadic dysmetria, impairment of smooth pursuit) are stressed.

Brain Diseases↗

PubMed1990

[Side effects of spinal nerve root radiography. How to reduce them?].

Contrastographic techniques with intrathecal injections (SRG, Myelo-CT) are widely employed in the diagnostic approach to lumbar pathologic conditions. These techniques allow pathologic changes to be demonstrated and the information they yield helps plan the correct surgical approach. However, these invasive examinations are seldom employed for the high incidence of side-effects. The latter are related to various causes, the identification of which can help reduce the side-effects themselves. The authors analyzed a study population of 522 patients subjected to radiculography, using needles of different gauges (18-23 G), and injected non-ionic contrast medium in doses ranging 5-10 ml. The incidence of side-effects was significantly higher in the patients suffering from usual headache (79/237 = 33%), in those under 40 (87/238 = 37%), and in female patients (86/221 = 39%). The incidence of side-effects was lower with fine needles (41/139 = 17%) and contrast medium in doses less than 8 ml (80/337 = 24%). The patients were divided into 4 subgroups according to the different doses of contrast medium administered and to needle gauges: the above parameters exhibited a percentage decrease (21/161 = 14%) with 21-23 G needles and 8 ml of contrast medium. The authors believe it possible to reduce side-effects by using fine needles and smaller doses of contrast medium.

Adolescent↗

PubMed1989

A protein induced by NGF in PC12 cells is stored in secretory vesicles and released through the regulated pathway.

We have previously described the isolation of a cDNA clone corresponding to an mRNA rapidly induced to high levels in PC12 cells by treatment with NGF. We report here the complete amino acid sequence of the protein (named VGF8a) as deduced by nucleotide sequencing of overlapping cDNA clones. VGF8a is particularly rich in proline residues and has a conspicuous number of short stretches of basic amino acid residues which may represent potential targets for proteolytic cleavage. Antibodies directed against recombinant VGF8a-beta-galactosidase fusion proteins were used for immunofluorescent staining of the protein in PC12 cells as well as for its localization, by Western blot analysis, in subfractions of cell homogenates. We demonstrate that in PC12 cells, VGF8a protein is stored in secretory vesicles and is released in response to a variety of stimuli that are known to induce the regulated secretion of neurotransmitters.

Adrenal Gland Neoplasms↗

PubMed1989

Cerebral blood flow and plasma free tryptophan in cirrhotics with and without hepatic encephalopathy.

Cerebral blood flow (CBF), measured by the non-invasive 133-Xenon inhalation method, plasma levels of ammonia (NH3) and free tryptophan (fTRP) were determined in 30 cirrhotic patients without overt encephalopathy. Psychometric evaluation detected subclinical hepatic encephalopathy (SHE) in 20 of them, and was normal in the other 10. A significant CBF difference (p less than 0.05) was found between the SHE and the non-SHE patients. fTRP levels were significantly (p less than 0.05) higher in patients with SHE than in those without SHE, and a significant negative correlation (p = 0.003) was found between CBF values and fTRP in the whole group of patients. NH3 did not differ in the two subgroups and did not correlate with CBF values. It is concluded that CBF could have some implications in SHE, although its relevance is still unclear. The negative correlation between CBF and fTRP prompts further investigation concerning the relationships between plasma fTRP, brain serotonin, cerebral metabolism and blood flow in the development of brain derangement during cirrhosis.

Adult↗

PubMed1989

Tryglycylvasopressin-reduced portal and systemic concentrations of serum bile acids after exogenous chenodeoxycholic acid load in rats as a reflection of reduced splanchnic blood flow.

The effect of triglycylvasopressin (TGVP) on the absorption of chenodeoxycholic acid (CDCA) was investigated in three groups of six rats (controls, CDCA, CDCA + TGVP) through the evaluation of portal and caval serum bile acids (SBA) concentrations after an oral load with CDCA to investigate whether changes in this parameter reflect variations in splanchnic blood flow induced by a vasoconstrictor. The results indicate that CDCA was absorbed and led to a significant increase in SBA. This increase was reduced by TGVP administration: portal blood 380.0 +/- 61.2 vs 279.7 +/- 45.3; caval blood 151.8 +/- 45.7 vs 41.7 +/- 12.5 (mumol/l; mean +/- s.d.). This suggests that variations in SBA concentrations could reflect changes in splanchnic circulation.

Animals↗