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Biomedical subjects

A De Santis

Publications and source records attributed to A De Santis.

At least 19 recordsLinked to original sources
PubMed1992

Prevalence of hepatitis C virus antibodies and hepatitis C virus-RNA in an urban population.

Several studies had been carried out on anti-hepatitis C virus (HCV) prevalence in populations with blood exposure risks and in blood donors. New tests are now available which allow the investigation to extend to other parameters such as antibody type and HCV-RNA. In this study the prevalence of anti-HCV c100-3 and the associated epidemiological, clinical, and virological markers were evaluated in subjects from an urban population located in central Italy. In positive cases the time persistence of HCV-RNA and anti-HCV antibody pattern was studied. For this purpose, sera from 1,484 randomly sampled individuals, aged 30-69 years, collected in 1985 and stored at -80 degrees C were retrospectively tested. The prevalence was 0.87% (i.e., 13 anti-HCV c100-3 positive cases). A significant association was observed with raised alanine transaminase (ALT) levels (P less than 0.001). Paired serum samples from 11 out of the 13 subjects collected in 1985 and 1991 were tested by nested polymerase chain reaction (PCR) using primers from the 5' non-coding region and by 4-RIBA. Concordant RIBA patterns between 1985 and 1991 were observed in the majority of positive paired sera (7/9) as well as for HCV-RNA (6/9). HCV-RNA was present in sera simultaneously positive to both types of antibody or to anti-c100-3 or anti-c22 alone. A wide spectrum of viral and antibody patterns in anti-HCV c100-3 positive sera was observed in this urban population and persisted for at least 6 years.

Adult↗
PubMed1992

Risk factors for late posttraumatic epilepsy.

The usually accepted risk factors for late post-traumatic seizures (LPTS) are those identified years ago by Jennet: early post-traumatic seizure (EPTS), depressed fracture, intracranial haematoma. Prolonged unconsciousness (PTA greater than 24 hrs) is another factor usually added. More recently, personal experience of the Authors and the data of the literature, compel us to question the validity of known risk factors based on clinical data. Authors believe that the identification of patients at risk for LPTS depends mainly on the precise definition of trauma severity and on CT or surgically documented lesions of brain substance. Three groups of patients, characterized by the presence of one or more of the accepted risk factors of LPTS, have been studied. In our experience, while in adults the presence of documented cortico-subcortical lesions represents the main risk factor of LPTS, in children the appearance of EPTS per se increases the risk of LPTS, irrespective of the presence of documented brain lesions. Alteration of consciousness without a focal lesion, even if prolonged and severe, is not a risk factor for LPTS.

Adolescent↗
PubMed1992

Primary traumatic benign midbrain haematoma in hyperextension injuries of the head.

Primary traumatic brain stem injury occurring in isolation is not universally recognized as a distinct pathological entity which may follow a head injury. We describe two patients with clinical and radiological evidence of primary posttraumatic midbrain haemorrhage occurring in isolation associated with good recoveries. It is suggested that paramedian midbrain syndromes associated with midbrain haemorrhages should be recognized as a distinct, although unusual, complication of hyperextension injury to the head which may have a benign course.

Adult↗
PubMed1992

Bidirectional transmission in the cerebrobuccal connective of Aplysia during feeding.

The neuronal activity of the cerebrobuccal connective (CBC) of Aplysia was recorded, using 2 implanted electrodes, under three conditions; 1) in the absence of feeding behaviour, 2) during appetitive feeding behaviour and 3) during consummatory feeding behaviour. Cross-correlation analysis of the recordings was then performed to subdivide spikes on the basis of their direction and speed of propagation. This revealed differences in the neuronal activity during the 3 conditions. There was little activity in the CBC when animals were not feeding. During appetitive and consummatory feeding behaviour the activity in the CBC increased. Units travelling in each direction were present, but with differential activity during the 2 behavioural patterns.

Animals↗
PubMed1991

Gallstones in cystic fibrosis: a critical reappraisal.

Radiolucent gallstones are common in young adults with cystic fibrosis. In the mid-1970s, it was suggested that gallstones are made of cholesterol, but this hypothesis has never been tested. Several recent studies have shown that the detection of cholesterol monohydrate crystals in bile has high sensitivity and specificity for the diagnosis of cholesterol gallstones. We therefore used this approach to study 17 young adults with cystic fibrosis, 10 of whom had radiolucent gallstones. The two groups of patients were comparable in age and gender (all patients but one were male). Duodenal bile was obtained after gallbladder contraction with intravenous cerulein; it was used for lipid and protein chemistry studies and for polarizing microscopy. The latter was performed both in whole bile and in the postultracentrifugation (100,000 g) sediment. Bile cholesterol saturation did not significantly differ between patients with (1.21 +/- 0.28) or without gallstones (0.99 +/- 0.54). Slight cholesterol supersaturation was found in 7 of 10 gallstone and three of seven nongallstone patients. At no time were cholesterol crystals detected in either the group, even after bile ultracentrifugation. Two more cystic fibrosis patients with gallstones died of severe bronchopneumopathy, and small pigment gallstones were obtained at autopsy. At stone analysis, cholesterol content was 44% and 28% of dry weight, respectively. Infrared spectroscopy of stone powder was compatible with the presence of calcium bilirubinate and proteins as major components. We conclude that radiolucent gallstones of cystic fibrosis are not of the conventional cholesterol type.

Adolescent↗
PubMed1990

Prevalence of gallstones in patients with primary immunoglobulin deficiency. Evidence for lack of association.

In the early 1970s an increased prevalence of gallstones was reported in adults and children with immunoglobulin deficiency. As the advent of ultrasonography has largely changed the diagnostic approach to gallstones, we have reevaluated the prevalence of cholelithiasis in a group including 37 patients with common variable immunodeficiency and seven patients with other forms of primary immunodeficiency. All patients were receiving intravenous gammaglobulin replacement since 1983 or, in more recent cases, soon after the diagnosis was made, and therefore had relatively few infections. All patients underwent a hepatobiliary ultrasonogram and blood sampling. Data were compared, after age and sex standardization, with those obtained by the GREPCO in a free-living population of 1239 men and 1081 women. Only two women with immunoglobulin deficiency had gallstones. One of these was obese and had had one pregnancy. Both were asymptomatic. None of the patients studied had a history of cholecystectomy or evidence of biliary sludge. Thus, the observed prevalence rates of gallstone disease were 8.7% in women and 0% in males, respectively, against expected values of 9.5% and 3.2%. Immunodeficient patients expressed several putative risk factors for gallstones in the low range (body mass index, total and HDL cholesterol, and blood glucose in both sexes, and triglycerides in men). We conclude that gallstone disease is not more frequent in patients with immunodeficiency syndromes undergoing immunoglobulin therapy than in the general population.

Adult↗
PubMed1990

The frog spinal cord: a model to study methanethiol-central nervous system interaction.

1. The effects of methanethiol (MT), DL-dithiothreitol (DTT) and N-ethyl-maleimide (NEM) were studied on the electrical activities of the frog cord. 2. Methanethiol depressed spontaneous dorsal and ventral root potentials, whereas no effects were observed on evoked responses. 3. N-ethyl-maleimide, a SH modifying agent, irreversibly depressed electrical cord activities. 4. DL-Dithiothreitol, a SH reducing agent, dramatically increased spontaneous electrical cord pattern. 5. It is suggested that interneuronal membrane sulphydryl groups of dorsal horn cell population are involved in the origin of spontaneous electrical cord activities and that MT interacts with these interneurones, probably oxidizing membrane SH groups.

Animals↗
PubMed1990

Biliary sludge: a critical update.

Biliary sludge has been for many years a poorly defined entity, usually with low amplitude, nonshadowing echoes within the most dependent part of the gallbladder, which shift under the influence of postural changes. From a sonographic point of view, the detection of sludge implies the coexistence of small-sized, solid components and of a gel-like embedding material. The chemical nature of biliary sludge has recently been recognized to be predominantly composed of a coaggregate of cholesterol monohydrate crystals and liquid crystalline droplets, and in some cases, such as obstructive jaundice or symptomatic liver diseases, by bilirubin granules, all embedded in a gel matrix of mucous glycoproteins. From a pathogenic point of view, biliary sludge is often associated with biliary stasis, or with conditions characterized by impaired gallbladder contraction, such as prolonged total parenteral nutrition, fasting, and pregnancy. Other causes include mucus hypersecretion, which may favor cholesterol nucleation and crystal growth, and bile infection. Sludge may be an intermediate step in the formation of different types of stones. From an epidemiological point of view, sludge is quite rare in the asymptomatic, free-living population, but may be common in selected series of symptomatic patients. From a clinical point of view, sludge often has a fluctuating course, including frequent disappearances and reappearances, suggesting that the early stages of gallstone formation are reversible.

Bile↗
PubMed1989

Chronotropic and inotropic effects of atrial peptides on the isolated systemic heart of Octopus vulgaris.

The chronotropic and inotropic effects of four atrial peptides (cardiodilatin 1-16, atrial natriuretic factor 8-33 and atriopeptin I and III) on the isolated systemic heart of Octopus vulgaris were studied. Using a preparation that produces a physiological stroke volume at physiological input pressures, it was found that ANF, atriopeptin I and atriopeptin III exerted both negative chronotropic and inotropic effects. In contrast, cardiodilatin produced a positive inotropic effect. A dose-response curve of ANF is reported, showing a threshold concentration of about 10(-12) M. The pharmacological and physiological implications of these results are discussed in relation to some characteristics of the cephalopod systemic heart.

Animals↗
PubMed1989

Relationships between a neuronal buccal population and the peribuccal regions in Aplysia: an electrophysiological study.

1. The relationships between Aplysia buccal neurons projecting the cerebral ganglion (L cells) and peribuccal regions were studied by electrophysiological techniques. 2. Stimulation of the cerebral upper labial (UL) and anterior tentacular (AT) nerves produced excitatory postsynaptic potentials in L cells. 3. Sixteen cells out of 24 were found possess an axonal branch in the labial branch of the AT nerve, 1 out of 8 in the UL nerve. 4. These axonal branches did not show any direct motor or sensory function in "reduced" preparations. 5. A modulatory function for the axonal projections and a sensory role for the synaptic relationships are hypothesized.

Action Potentials↗
PubMed1989

Neuropsychological follow-up of patients operated for aneurysms of anterior communicating artery.

The neuropsychological outcome of 43 patients operated for ACoA aneurysms was assessed with a battery of 15 tests, tapping a wide spectrum of cognitive abilities. As a group ACoA aneurysms patients were impaired on 8 tests, including the three assessing memory. When however, patients falling below the cut-off point determined in normal controls were considered, 42% of the sample was unimpaired and only 35% fell on two or more tests. The analysis of single cases showed that memory was often affected, but short-term memory even more than long-term memory. In addition to the well known memory disorder, the patients showed a wide range of neuropsychological defects, including language and space functions. The hypotheses that could account for this broad-based neuropsychological impairment are discussed.

Follow-Up Studies↗
PubMed1989

Neuropsychological follow-up of patients operated for aneurysms of the middle cerebral artery and posterior communicating artery.

This study assessed with a neuropsychological battery the outcome of 27 patients operated on for an aneurysm of the Middle Cerebral Artery a mean of 35 months before, and of 27 patients operated for aneurysms of the Posterior Communicating Artery, a mean of 47 months before. Both groups showed a defective pattern of performance that was related to the hemispheric side of the aneurysm with left-sided patients impaired on naming, verbal fluency and verbal short-term memory and right sided patients on both short-term and long-term spatial memory and discrimination of line orientation. In single cases, the scope of neuropsychological impairment was sometimes wider than that expected only on the basis of the competence of the affected hemisphere.

Follow-Up Studies↗
PubMed1989

New evidence that L-glutamate is a transmitter at the squid giant synapse.

Experiments are described showing unequivocally that transmission at the squid giant synapse can be reversibly blocked by L-glutamate and its agonists kainate, quisqualate and AMPA, though not by NMDA. This effect is presumably brought about by desensitization. The glutamate antagonists cis-2,3-PDA, GAMS and the new quinoxalinediones CNQX and DNQX are also potent reversible blockers. These findings provide new evidence that L-glutamate is a transmitter at the giant synapse and further suggest that the glutamate receptor may be of the non-NMDA type.

Action Potentials↗
PubMed1989

[Diffuse traumatic cerebral injuries in children].

A consecutive series of 41 patients aged less than 16 and admitted to the Department of Neurosurgery of the University of Milan in the period 1977-1978 following serious cranioencephalic trauma with Glasgow Coma Score (GCS) less than or equal to 7, duration of coma longer than 24 h and CT picture of diffuse lesion has been examined. These patients account for 5% of the paediatric cranial traumas observed in the same period and 66% of those in a state of coma. The CT picture made it possible to split patients into 3 groups: a) those without visible cerebral lesions and with subarachnoid and cisternal spaces present; b) those with small hyperdense lesions due to intraparenchymal or median/paramedian subcortical shearing lesions; c) those with marked constriction or absence of the 3rd ventricle and of the perimesencephalic cisterns. The first two pictures (a, b) were considered to be the expression of diffuse axonal damage, the last (c) of diffuse cerebral swelling. Intracranial pressure was monitored in about 50% of patients. The overall outcome of the series was favourable in more than 68% of cases with total mortality of 26.8%. Analysis of individual tomographic categories, however, showed that whereas the group of patients with diffuse axonal lesion presented nil mortality, those with diffuse cerebral swelling had 52% mortality owing to the onset of refractory intracranial hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗