Search PubMed⌕ Search

Biomedical subjects

G Andrioli

Publications and source records attributed to G Andrioli.

At least 37 records · Page 2Linked to original sources
PubMed1996

Dual effects of diclofenac on human platelet adhesion in vitro.

The effect of two non-steroidal anti-inflammatory drugs on the adhesion function of human platelets was evaluated. Platelets isolated from healthy human subjects were treated for 10 min with the indicated drugs and then incubated in fibrinogen-coated microwell plates in the absence or in the presence of ADP (10 microM) and thrombin (0.05 U/ml). After 1 h of incubation, adherent platelets were measured using an enzymatic assay. ADP- and thrombin-stimulated adhesion was significantly inhibited by high doses ( > 500 microM) of diclofenac, while doses ranging from 50 to 300 microM stimulated adhesion in the absence of agonists (resting platelets). A similar stimulatory effect on platelet adhesion was observed also with 200-500 microM flurbiprofen. Moreover, immunocytofluorimetry demonstrated that diclofenac dose-dependently (100-500 microM) induced the expression of GMP-140 and increased the expression of GPIIb/IIIa on the membrane of unstimulated platelets. High doses ( > 500 microM) of this drug inhibited thrombin-stimulated expression of GPIIb/IIIa and GMP-140.

Adenosine Diphosphate↗
PubMed1996

Study of platelet adhesion in patients with uncomplicated hypertension.

OBJECTIVE: To evaluate platelet function in patients with essential hypertension by sensitive methods investigating platelet adhesion and expression of some platelet glycoproteins (GP), namely GPIIb/IIIa (CD41/alpha 2 beta 3) and GMP-140 (CD62/P-selectin/PADGEM). Other markers of platelet (beta-thromboglobulin) and endothelium activation (von Willebrand factor) were also measured. METHODS: We studied 21 uncomplicated essential hypertensive patients and 20 healthy normotensive control subjects, non-smokers, matched for age and sex. Resting and stimulated platelet adhesion was performed with a colorimetric method using the activity of platelet acid phosphatase for the determination of the number of platelets adhering to human plasma- or fibrinogen-coated microwells. Platelet activation was characterized by flow cytometric measurement of GPIIb/IIIa and GMP-140 in whole blood and washed platelets suspensions, with antihuman fluorescent monoclonal antibodies. RESULTS: Thrombin-stimulated platelet adhesion to human plasma-coated microwells was significantly higher in hypertensive patients than in control subjects (0.05 U/ml thrombin: 13.4 +/- 1.0 versus 7.7 +/- 0.6% adhesion; 0.1 U/ml thrombin: 19.4 +/- 2.3 versus 12.6 +/- 1.8%; means +/- SEM), whereas platelet adhesion to fibrinogen-coated wells did not differ in the two groups. Flow-cytometry analysis of whole blood demonstrated a significantly increased expression of GMP-140 in hypertensive patients compared with normal subjects (percentage of CD62+ platelets: 7.3 +/- 1.2 versus 3.7 +/- 1; means +/- SEM), whereas the expression of GPIIb/IIIa did not differ in the two groups (percentage of CD41a+ platelets: 72.5 +/- 4.5 versus 70.4 +/- 3.9). Moreover, flow cytometry showed an increased size of platelets in hypertensive patients compared with that in control subjects (forwards scattering: 46.5 +/- 1.5 versus 38.9 +/- 1.1; means +/- SEM). Flow-cytometric evaluation of washed platelet suspensions showed no statistically significant differences between the expression of GMP-140 and GPIIb/IIIa in the two groups. beta-Thrombo-globulin plasma levels were higher in hypertensive patients than they were in normal subjects (36.3 +/- 2.0 versus 28.2 +/- 1.3 ng/ml; means +/- SEM). Von Willebrand factor plasma levels were not significantly different in the two groups (101.2 +/- 10.3 versus 86.3 +/- 5.6 U/dl). CONCLUSIONS: These findings provide further evidence that there is a significant, albeit weak, platelet activation in hypertensive patients compared with normal subjects.

Adult↗
PubMed1996

The antiplatelet effects of a new nitroderivative of acetylsalicylic acid--an in vitro study of inhibition on the early phase of platelet activation and on TXA2 production.

We studied in vitro the antiplatelet activity of a new nitroderivative chemically related to acetylsalicylic acid: 2 acetoxybenzoate 2-[1-nitroxy-methyl]-phenyl ester (NCX 4016), in order to identify any effects due to the release of nitric oxide and the blockade of cyclo-oxygenase. The effects of scalar doses of NCX 4016 on the early phase of platelet activation, platelet aggregation and thromboxane A2 production were investigated. We observed inhibitory effects of NCX 4016 on platelet adhesion (IC50 = 7.3 x 10(-5) M), platelet cytosolic calcium concentration, assayed by fluorescent probe Fura 2, and the expression of glycoprotein IIb/IIIa (CD41/alpha IIb beta 3) (IC50 = 3.4 x 10(-5) M) and P-selectin (CD62/GMP-140) (IC50 = 4.9 x 10(-5) M) measured by flow cytometry. NCX 4016 also prevented thrombin-induced platelet aggregation (IC50 = 3.9 x 10(-5) M). None of these parameters were affected by acetylsalicylic acid. These inhibitory activities of NCX 4016 were abolished by oxyhaemoglobin and methylene blue. Intracellular cyclic GMP observed during thrombin-induced aggregation was increased by incubation with NCX 4016. These results appear to be attributable to the release of nitric oxide, which activates soluble platelet guanylylcyclase and promotes intracellular cyclic GMP increase. NCX 4016 almost completely inhibited platelet thromboxane A2 production and arachidonic acid-induced platelet aggregation. This also occurred in the presence of oxyhaemoglobin and methylene blue, indicating that its antiplatelet activity can be attributed not only to nitric oxide release but also to cyclo-oxygenase inhibition.

Adult↗
PubMed1995

Spinal dermoid cysts originating intracranial fat drops causing obstructive hydrocephalus: case reports.

The authors report two cases of spinal dermoid cysts whose rupture originated the migration of free fat drops into the ventricles and intracranial subarachnoid spaces. In both cases the fat drops caused obstructive hydrocephalus, which represents a quite exceptional complication. Moreover, one of the cases is unique, since the finding of intracranial fat causing hydrocephalus considerably preceded the discovery of the spinal neoplasm. The authors suggest that the finding of intracranial fat in the absence of a local source makes the search for a intraspinal dermoid or epidermoid tumor mandatory.

Cerebral Ventricles↗
PubMed1994

A colorimetric method for the measurement of platelet adhesion in microtiter plates.

A procedure for the determination of the adhesion of human platelets to protein-coated culture microwells was developed. The number of platelets was quantitated by measuring the activity of acid phosphatase, a platelet enzyme whose activity is stable independently of platelet stimulation and is not released. Isolated and washed platelets were incubated in 96-well microtiter plates with flat-bottom wells that had been precoated with various compounds, including collagen, fibrinogen, human plasma, and human albumin. At the end of incubation (optimal time: 40-60 min), nonadherent platelets were washed out, adherent platelets were solubilized with Triton X-100, and the acid phosphatase activity was measured by using the substrate p-nitrophenyl phosphate. The p-nitrophenol produced was measured with a microplate reader at 405 nm and the percentage of adhesion was calculated with reference to known platelet standards. ADP and thrombin stimulated platelet adhesion in a dose-dependent manner to fibrinogen and human plasma, but not to human albumin. Platelets adhered to collagen even in the absence of stimulants. Simultaneous evaluation of adhesion and aggregation demonstrated that with ADP as stimulus, but not with thrombin, the two platelet responses were dissociated. Microscopic examination of culture wells showed that most of platelets adhered as single cells and not as aggregates. The sensitivity of this method allowed the assay of platelet adhesion by using only 2.5 x 10(5) platelets/well.

Acid Phosphatase↗
PubMed1994

Brain metastasis from endometrial carcinoma. Report of two cases.

The authors report two cases of surgically treated brain metastases from endometrial cancer which are quite unusual occurrences. In one of them the brain lesion was the presenting symptom of malignancy while in the other the metastasis was discovered after the primary tumor had been treated. Both the brain lesions were scarcely differentiated adenocarcinomas which closely resembled the uterine primaries histologically. The authors review the four cases reported in the literature and discuss the clinical features and the treatment of this disease. The analysis of cases shows that the metastatic potential of endometrial cancer is extremely variable and unpredictable but less severe than that observed in ovarian or cervical tumors. The authors suggest that the erratic behaviour of endometrial cancer may justify an aggressive (though necessarily palliative) approach to brain metastases even in the presence of circumscribed metastatic involvement.

Adenocarcinoma, Papillary↗
PubMed1994

Urokinase thrombolytic therapy of pulmonary embolism in neurosurgically treated patients.

Pulmonary embolism (PE) is a severe complication in neurosurgery. The best treatment of PE is thrombolytic therapy, but the presence of either intracranial neoplasm or recent neurosurgical procedures is considered a major contraindication to this therapy. We have used urokinase thrombolytic therapy in nine of our patients with severe PE that occurred from 7 to 34 days after a neurosurgical operation. All patients survived. No intracranial hemorrhage occurred. We also advocate thrombolytic therapy for severe PE in patients who were recently operated on by neurosurgical procedure.

Adult↗
PubMed1994

Cerebellopontine angle osteoma causing trigeminal neuralgia: case report.

A case of cerebellopontine angle petrous bone osteoma manifesting as homolateral trigeminal neuralgia and causing a mild brain stem compression is presented. The literature concerning osteomas and particularly those affecting the temporal bone is reviewed. This is the second report of an osteoma located on the inner surface of the petrous bone and causing intracranial complications. Moreover, we discuss the intracranial tumors presenting with trigeminal neuralgia or atypical facial pain.

Brain Stem↗
PubMed1994

Intraventricular pneumocephalus after posterior fossa and CSF shunting surgery. Case report.

The authors report a case of tension intraventricular pneumocephalus developed six months after the removal of an acoustic neuroma and a CSF ventriculoperitoneal shunt procedure due to a concomitant hydrocephalus. A review of the literature show only 19 cases of CSF shunt complicating pneumocephalus. The authors discuss both about the etiology of pneumocephalus and its therapeutic options. In our case we were unable to preoperatively localize the cranial base communication allowing intracranial air antry. The literature show however that eroded or thinned bone areas may be multiple and even diffuse their development depending upon several factors. We suggest in these cases a direct surgical repair through a craniotomy, as reported by others, is not mandatory. According to the etiology of pneumocephalus a temporary extraventricular drainage and the revision of the shunting pressure regimen may represent an effective treatment of this complication.

Cerebrospinal Fluid Shunts↗
PubMed1993

Dual effects of formylpeptides on the adhesion of endotoxin-primed human neutrophils.

Neutrophils, treated with sequential additions of bacterial products such as endotoxin (E. Coli lipopolysaccharide, LPS) and the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP), undergo to metabolic activation and express membrane-anchoring proteins that promote adhesion to serum-coated culture wells. By investigating the dose-response relationships of these phenomena, we have found that: (a) resting neutrophils do not produce a significant amount of superoxide (O2-) and show only minimal adhesion to serum-coated plastic surfaces; (b) fully activatory doses (> 5 x 10(-8) M) of fMLP induce the release of O2- and a significant increase of the cell adhesion; (c) pretreatment of the cells for 1 h with LPS augments cell adhesion to serum-coated culture wells in the absence of further stimulation and primes the neutrophils to enhanced fMLP-dependent O2- release; (d) addition of low, substimulatory doses of fMLP (from 10(-10) M to 5 x 10(-9) M) inhibits and reverses the adhesion of LPS-treated cells, (e) high fMLP doses ( > 10(-7) M) are additive to LPS in promoting adhesion. Phorbol-myristate acetate (> 10(-9) M) increased adhesion in both normal and LPS-treated neutrophils, but low doses of this stimulant did not inhibit adhesion. Low doses (10(-9) M) of fMLP increased intracellular cyclic AMP in both normal and LPS-treated neutrophils, suggesting that stimulus-induced rises in cAMP may be the negative signal responsible for down-modulation of adhesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, CD↗
PubMed1991

"Unusual" MRI appearance of sphenoid sinus mucocele.

The authors report a case of sphenoid sinus mucocele which exhibited unusual MRI features. However a review of the literature shows that these lesions may present with different MRI appearances probably related to the variability of the cyst content. Further series are needed for a better definition of the MRI behaviour of the lesions.

Adult↗
PubMed1991

Brain stem abscess treated successfully by medical therapy.

A case of a solitary brain stem abscess in a 55-year-old man is presented. The computed tomographic scan and clinical picture allowed the presumptive diagnosis to be made. The abscess resolved completely after treatment with chloramphenicol, vancomycin, and ceftazidime administered intravenously. Medical therapy should be considered as an effective treatment of a brain stem abscess, provided the antibiotic therapy is administered under close clinical and computed tomographic monitoring.

Brain Abscess↗
PubMed1988

Extracranial posterior inferior cerebellar artery aneurysm causing isolated intraventricular hemorrhage: a case report.

The authors report the unusual case of an aneurysm arising on an extracranial loop of the left posterior inferior cerebellar artery (PICA). The computed tomographic scan showed an isolated hemorrhage in the lateral ventricles, and the lesion was recognized 1.5 cm below the foramen magnum at the level of the atlas. The literature concerning peripheral PICA aneurysms is reviewed and the clinical and radiological features of these lesions are discussed. A tendency for subarachnoid bleeding from distal PICA aneurysm ruptures to spread into the ventricular system is suggested. The diagnosis of distal PICA aneurysm should also be considered in cases of isolated intraventricular hemorrhage without obvious parenchymal or subarachnoid hemorrhage. The need for four-vessel angiography when studying patients suffering from a subarachnoid hemorrhage is stressed.

Adult↗