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Biomedical subjects

A Riva

Publications and source records attributed to A Riva.

At least 163 records · Page 9Linked to original sources
PubMed1993

Acute cholecystitis potentiates bradykinin stimulated fibroblast prostanoid release in the rabbit.

Gallbladder explants from control rabbits and rabbits subjected to bile duct ligation (BDL) for 24 and 72 h (cholecystitis model) were placed in cell culture to determine the source for increased gallbladder prostanoid synthesis during cholecystitis. Cultures from control and 24 h BDL gallbladders grew spindle shaped fibroblasts which did not exhibit increased prostanoid synthesis. 72 h BDL gallbladder cell cultures grew large polygonal shaped cells which appeared to be 'stimulated fibroblasts' by light and electron microscopy and were associated with increased basal and bradykinin stimulated 6-keto-PGF1 alpha release and increased content of prostacyclin synthase when measured by enzyme immunoassay and protein immunoblot analysis respectively. Use of bradykinin antagonists showed that the bradykinin BK2 subtype receptor was the most prominent in the 72 h BDL cell cultures. The 'stimulated fibroblasts' were the source of bradykinin stimulated gallbladder 6-keto-PGF1 alpha synthesis in the inflamed rabbit gallbladder which was mediated by the bradykinin B2 subtype receptor.

6-Ketoprostaglandin F1 alpha↗
PubMed1993

Pulmonary thromboembolism in leukaemic children undergoing bone marrow transplantation.

Of 67 leukaemic children transplanted in our BMT unit 3 presented with severe acute respiratory syndrome associated with pulmonary thromboembolism (PTE) as diagnosed by scintiscan and/or angiography in the first month after BMT. Intervention with continuous positive pressure ventilation, urokinase (loading dose, then continuous infusion for 12-18 h) and heparin (continuous infusion for an average of 10 days) has been carried out successfully in two cases. In conclusion, when evaluating patients undergoing BMT and developing early pulmonary complications, PTE must be considered. The pathogenesis of PTE is still difficult to ascertain but urokinase therapy may reduce early morbidity.

Adolescent↗
PubMed1992

Immunocompetent cell markers in human fetal astrocytes and neurons in culture.

During the past few years, evidence has accumulated that interaction with peripheral immune cells as well as immunoregulatory functions in the central nervous system (CNS) can be played by several types of brain resident cells. Since very little information is available in man, however, we investigated the presence of markers so far considered typical of immunocompetent cells in in vitro cultures of human fetal brain. Immunocytochemistry at the light, scanning, and transmission electron microscopic levels revealed positivity for a very restricted range of macrophage antigens in astrocytes, which, however, were incapable of phagocytosis. In particular, expression of the major histocompatibility complex-class II antigen HLA-DR was observed in the cytoplasm and on the cell surface of GFA-P+ astrocytes and increased with time in culture and cell passages. Among the T-lymphocyte markers tested, Thy.1 and CD4 were positive. Both neurons and astrocytes carried Thy.1 from early cell passages. Noteworthy was the presence of CD4, which serves as the receptor for AIDS virus, in neurons from the first 2 weeks, whereas astrocytes became positive after only 4-6 weeks. Even if most staining was in the cytoplasm, some was exposed on cell surface. Astrocytes were found positive for the B-lymphocyte marker CD21, the cellular receptor for Epstein-Barr virus, whereas CD24 was detected in both neurons and astrocytes. Both antigens are related to B-cell proliferation. Results are in favour of the hypothesis of human brain cells being actively involved in CNS immunological events.

Astrocytes↗
PubMed1992

Selective intra-arterial chemotherapy with BCNU in recurrent malignant gliomas.

Study of intra-arterial BCNU in 12 patients with recurrent glioblastoma multiforme and 5 patients with recurrent anaplastic astrocytoma already treated by surgery and radiotherapy indicates that the risk of BCNU toxicity can be reduced by the use of relatively low doses (160-180 mg/m2) of BCNU, the use of dextrose as solvent, selective injections of BCNU, and fast "bolus" injections of drug. No certain toxic effects of BCNU were observed in the 17 patients treated this way. Anaplastic astrocytomas, particularly in young patients, seem to respond relatively well to this treatment.

Adult↗
PubMed1992

A phase II study of high dose epirubicin in unresectable non small cell lung cancer.

Epirubicin (EPI), a doxorubicin analogue, is reported to have equal antitumour activity with lower cardiac and systemic toxicity. Recently, the maximum tolerated dose of this drug has been revised upwards with reported increased response rates in several malignancies. We initiated a phase II study of high-dose EPI as initial treatment for patients with advanced non-small cell lung cancer (NSCLC) (stage III and IV). Between May 1988 and November 1989, 25 patients were entered. The starting dose of EPI was 135 mg m-2, with dose attenuations and escalations of 15 mg m-2 based on mid-cycle evaluation of toxicity. Treatment was repeated every 3 weeks. Nine partial responses (36%, 95% CI: 18-57.5%) and 11 patients with disease stabilisation (44%) were observed. Median (range) time to progression was 19 (3-70) weeks. Median (range) survival is 32 (9-116+) weeks. There were no treatment related deaths. Major side effects were leukocytopenia WHO grade III/IV (23% of courses) and mucositis WHO grade II/III (15% of courses). In two patients left ventricular ejection fraction decreased greater than 15% compared to baseline values after a cumulative Epirubicin dose of 435 mg m-2, and therefore went off study. In none of the patients clinical signs of congestive heart failure were observed. We conclude from our data that high-dose EPI, contrary to previous negative studies using lower doses of EPI, ranks amongst the most active regimens against advanced NSCLC. Toxicity of high-dose EPI is moderate. Further evaluation of this compound in combination regimens is recommended.

Adult↗
PubMed1992

Superficial siderosis of the central nervous system: neuroradiological evaluation of two cases.

We present 2 cases of superficial siderosis of the central nervous system secondary to chronic subarachnoid bleeding. The diagnosis was made with MR and cerebrospinal fluid (CSF) examination. MR showed, in T2-weighted images, superficial hypointensity of the cervical cord, brainstem, cerebellum, and basal cisterns due to hemosiderin deposits. CSF was xanthochromic, with increased protein content. In 1 of the 2 cases also the CT examination was positive, showing a hyperdense rim around the brainstem. A complete neuroradiological evaluation (MR, CT, angiography and myelography) did not permit to detect the source of the bleeding.

Central Nervous System Diseases↗
PubMed1992

The myoepithelial and basal cells of ducts of human major salivary glands: a SEM study.

The cytoarchitecture and distribution of myoepithelial (mecs) and basal (bc) cells of intralobular (intercalated, striated) and interlobular (excretory) ducts of human major salivary glands were studied by SEM through a variety of maceration and microdissection techniques. Intercalated ducts are covered by mecs which, unlike the large stellate cells of acini, are spindle shaped. Small star shaped mecs are rarely observed even in the most distal striated ducts, while no such cells are seen in excretory ducts. Basal cells form a more or less continuous row of small, basally placed cells in excretory ducts. Sparse bc are occasionally present in proximal striated ducts as well. Following microdissection, bc exhibit a cup-shaped apex which embraces the convex base of principal cells. This configuration may explain why, in TEM, bc seem to possess lateral processes which may be mistaken for mecs processes. Moreover, the lateral surfaces of bc do not exhibit the complex system of plasmalemma folds typical of principal cells. The present study demonstrates that fusate mecs are present in intercalated ducts and that basal cells are distinct from myoepithelial cells. These results may have some relevance in histogenetic studies of salivary gland neoplasms.

Adolescent↗
PubMed1992

Scanning electron microscopy of proteoglycans in metaphyseal cartilage.

Alcian blue (AB) was used for scanning electron microscope investigations on metaphyseal cartilage. In the pericellular area three-dimensional network connecting the cell membrane surface to the lacunar wall is evident. The network is formed by very long rod-like filaments about 50 nm thick. The segments may be interpreted as the proteoglycans (PGs) of the pericellular area. In the pericellular area in hypertrophic and degenerative zones, the rod-like segments are closely connected to "chain granules" which are the morphological expression of Ca-P non crystalline compounds. The rod-like segments are not at all evident either in glutaraldehyde-osmium fixed fragments or in predigested-(streptococcal hyaluronidase and chondroitinase) AB stained ones. It is concluded that AB is a good method to detect the three-dimensional spatial disposition of cartilage PGs.

Animals↗
PubMed1992

A correlative SEM/TEM examination of the endothelium surface in neural capillaries.

The modifications of the endothelial surfaces were analyzed in growing neural microvessels by scanning and transmission electron microscopes in the optic tecta of chick embryos and chickens. The endothelial inner aspect appears regular and smooth in the early stages of the vessel growth (7th incubation day). Later (14th incubation day) both the abluminal and luminal surfaces of the endothelium follow a very sinuous course and the luminal ones appear extremely rich in pleomorphic microprojections. When the endothelium differentiation is concluded (5-day-old chicken), the cells are very thin and again exhibit regular and smooth surfaces. These findings reveal a great mobility of the cell membrane of the endothelial cells when they are growing longer and thinner by a moulding process. Moreover, the presence of a number of pinocytotic pits in the embryo vessels would indicate that the neutral vessels, provided with a typically low pinocytotic activity in the adult life, are engaged in this function during development.

Aging↗
PubMed1991

Soluble interleukin-2 receptor decrease in the sera of HIV-infected patients treated with zidovudine.

Laboratory parameters which are modified following administration of zidovudine are becoming increasingly useful in monitoring the efficacy of treatment of early stages of HIV-1 infection. The serum levels of soluble interleukin (sILR)-2 receptor, which have been reported to increase early in HIV-1 infection, were found to be significantly lower in 24 patients being treated with zidovudine than in 69 patients who were not treated, 28 of whom had CD4+ counts greater than 400 x 10(6)/l, and 41 less than 400 x 10(6)/l, respectively (P less than 0.0001). A prospective study group of 33 subjects treated with zidovudine demonstrated a decrease in sIL-2R during therapy (base values 2113 +/- 1131 versus 1444 +/- 728 after 90 days of therapy; P less than 0.0007). The reduction of sIL-2R was greater in those subjects were p24 antigen became negative during treatment. sIL-2R therefore seems to be a useful tool in the monitoring of therapy with zidovudine.

CD4-Positive T-Lymphocytes↗
PubMed1991

3D microanatomy of human parotid gland.

We have performed a scanning electron microscope study on human parotid gland. By using a variety of techniques of maceration and digestion we have shown the 3D morphology of cells and of isolated endpieces.

Anatomy↗
PubMed1991

[The effects of administering surfactant to two adolescents with leukemia suffering from respiratory distress].

Two adolescents (12 years old, suffering from acute lymphoid leukaemia (LLA) and 16 years old with acute myeloid leukaemia (LMA)) were treated with porcine surfactant (Curosurf). The indication for this treatment was a severe Respiratory Distress Syndrome (RDS) which appeared during leukaemia treatment. Pulmonary thrombo-embolism was suspected. The surfactant administered improved ventilation and oxygenation, enabling confirmation of the diagnosis which would otherwise have been impossible due to the seriousness of their condition.

Acute Disease↗
PubMed1990

[Gonococcal endocarditis: an infection as rare as it dangerous. Apropos of a case: the importance of suspicion in diagnosis and of immediate treatment].

Gonococcal endocarditis, although extremely rare, is increasing in frequency, particularly among young exposed patients. It has a distinct predilection for aortic and mitral valve involvement and tends to cause rapid valvular destruction and acute heart failure. Blood cultures are often negative during the first (3 to 31) days. Echocardiography with Doppler is helpful in detecting valvular vegetations, regurgitation and signs of hemodynamic deterioration. Early antibiotic treatment may stabilize the hemodynamic situation only in mitral but not in aortic valve involvement, which necessitates prompt valvular replacement in the event of perforation and/or annulus abscess. Gonococcal endocarditis should be the first item to be excluded in cases of fever with systemic symptoms in young people with a history of sex-transmitted disease. We present a typical case.

Adult↗