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Biomedical subjects

P Ricci

Publications and source records attributed to P Ricci.

At least 91 records · Page 5Linked to original sources
PubMed1992

Significance of IgM antibody to hepatitis C virus in patients with chronic hepatitis C.

We assessed the correlation between the positivity for serum IgM antibody to hepatitis C virus and the activity of liver disease in patients with chronic hepatitis C virus infection. Serum samples were taken from 10 antibody to hepatitis C virus-positive asymptomatic patients with normal serum ALT levels, from 14 untreated patients with clinically and histologically proven chronic hepatitis C and from 26 patients with clinically and histologically proven chronic hepatitis C assigned to receive recombinant interferon alpha-2a (6 million IU three times a week for 6 mo). Each serum specimen was tested for IgM antibody to hepatitis C virus-associated C100-3 antigen by enzyme-linked immunosorbent assay. Patients were observed for at least 12 mo. All 10 patients with normal ALT values tested negative for IgM antibody to hepatitis C virus. In contrast, 33 of 40 (82%) patients with chronic hepatitis C had IgM antibody to hepatitis C virus, and a positive correlation was seen between the ALT level and the level of IgM antibody to hepatitis C virus (r = 0.803, p less than 0.001). During interferon treatment, ALT levels declined into the normal range in 18 of 26 treated patients (69%) and remained normal after stopping treatment in 8 patients (31%). In untreated patients, in treated patients who did not respond to interferon treatment and in responder patients who relapsed, no significant changes in IgM antibody to hepatitis C virus levels were seen during the study period. In contrast, IgM antibody to hepatitis C virus became undetectable by the end of interferon treatment in seven of eight patients with a sustained response.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Migration of the Fungal Protein Cryptogein within Tobacco Plants.

Cryptogein (CRY), a protein secreted by Phytophthora cryptogea, causes necrosis on tobacco (Nicotiana tabacum) plants at the site of application (the stem or the roots) and also on distant leaves. Autoradiography of plantlets after root absorption of radioiodinated CRY demonstrated a rapid migration of the label to the leaf lamina via the veins. Using an anti-CRY antiserum, a CRY-related antigen was detected in the stem and leaves of CRY-treated plants at a distance from the site of application. This antigen had the same molecular weight as CRY and was detected in the leaves as early as 1 hour after stem treatment, i.e. long before necrosis was detectable. The antigen was also detected in plants inoculated with P. cryptogea. The distant location of the necrosis induced by the fungus or by CRY can be ascribed to the migration of this protein, which is toxic to tobacco cells. It is proposed that CRY, which also elicits defense reactions in tobacco, might contribute to the hypersensitive response of tobacco to P. cryptogea.

Journal Article↗
PubMed1991

Efficacy of amphotericin B encapsulated in liposomes (AmBisome) in the treatment of invasive fungal infections in immunocompromised patients.

One hundred and twenty-six patients were treated for 137 episodes of fungal infection with liposomal amphotericin B (AmBisome) at 43 investigational centres. Among the patients were 72 with malignancies, 17 organ transplant recipients, 20 patients with immunological disorders and 17 others. AmBisome treatment was instituted after toxicity from previous amphotericin B treatment in 49 cases, nephrotoxicity or renal insufficiency in 40 and failure of previous antifungal treatment in 41. One hundred and eight episodes were clinically evaluable; among these 52 were caused by Candida spp. and 34 by Aspergillus spp. Ninety-nine patients were treated for at least eight days with a maximum dose of 0.7-5 mg/kg/day. Among 64 cases with proven invasive fungal infection 58% were cured. Fungi were eradicated in 35 of 54 (65%) mycologically evaluable cases. The cumulative dose was 3.2 +/- 3.2 (mean +/- S.D.) in cases where fungi were eradicated in comparison with 3.3 +/- 2.3 g in cases where fungi persisted. The eradication rate was 83% for Candida spp. compared with 41% for Aspergillus spp. (P less than 0.01). Among 24 cases with presumptive invasive fungal infections 14 (58%) were cured. Candida spp. were eradicated in seven of ten of these cases. Among 11 cases with superficial fungal infections eight were cured and three improved. Candida spp. were eradicated in four of five patients. It is concluded that AmBisome is an effective antifungal agent in a majority of patients with invasive or superficial fungal infections.

Adolescent↗
PubMed1991

Responses of Cultured Tobacco Cells to Cryptogein, a Proteinaceous Elicitor from Phytophthora cryptogea: Possible Plasmalemma Involvement.

In culture, the phytopathogenic fungus Phytophthora cryptogea secretes a protein which elicits hypersensitive-like necroses and protects tobacco plants against invasion by the pathogen Phytophthora parasitica var. nicotianae. This protein, named cryptogein, has been purified and its amino acid sequence determined. In this work, we studied the effect of cryptogein on tobacco cell suspension cultures. Cryptogein was lethal at about 0.10 micromolar. When added at sublethal doses, it elicited the production of ethylene and phytoalexins. It also induced a rapid increase in pH and conductivity of the extracellular medium without affecting the integrity of the plasma membrane. Cryptogein reduced the fusicoccin-induced acidification of the extracellular medium. The concentration which inhibited the fusicoccin response by 50% was 0.8 nanomolar, while 1 micromolar erythrosine B, an ATPase inhibitor, was needed to produce the same inhibition. However, cryptogein did not inhibit the activity of a purified plasma membrane ATPase. Results of binding studies with whole cells suggested the presence of elicitor-binding sites with a high affinity for cryptogein. The involvement of the plasma membrane during the initial interaction between elicitor and cells is discussed.

Journal Article↗
PubMed1991

Ticlopidine lowers plasma fibrinogen in patients with polycythaemia rubra vera and additional thrombotic risk factors. A double-blind controlled study.

Thirty-seven patients affected by polycythaemia rubra vera (PRV) and with at least one additional thrombotic risk factor (overt vascular disease, diabetes mellitus, treated hypertension, smoking habit, plasma hyperviscosity, hyperfibrinogenemia) were enrolled in a double-blind randomized placebo-controlled study, and 18 were given ticlopidine 250 mg, b.i.d., for 60 days. All the patients had previously been submitted to cytoreduction, and PRV was under control in all cases at the start of the study. During the study, the haematological parameters were controlled every 15 days, and venesection was performed if haematocrit was greater than 46%. Whole blood viscosity, at low and high shear rates, plasma viscosity, and fibrinogen were measured on days 0 and 60. In the ticlopidine group, we recorded a significant 13.14% reduction of the mean fibrinogen level after treatment (390 +/- 63 vs. 449 +/- 97 mg/dl, p less than 0.01). All the other haemorheological parameters were not significantly modified by ticlopidine treatment, nor were there significant modifications recorded in the placebo group. Our study shows that ticlopidine may reduce a probable thrombotic risk factor (hyperfibrinogenemia) in PRV patients.

Aged↗
PubMed1991

[Effect of the resection margin and the extrarectal spread on the recurrence following 2 types of surgical procedures in rectal cancer].

A prospective unrandomized clinical study was conducted to determine the incidence of local recurrences after radical surgery and to ascertain whether the anterior resection could be an effective approach in cases of the tumours of the rectum, also in presence of the unsatisfied distal clearance and the extraparietal spread. For this purpose the length of the rectum below the tumor, mesorectum included, was cut in little cubes of 1 square cm and 10 microslices/cm at random were histologically examined to locate the intramural diffusion and extraparietal spread. Sixty-one patients undergoing curative surgery for rectal cancer entered the trial. Thirty-seven of them have been operated on by anterior resections (AR) and twenty-four by abdominal-perineal amputation. Thirteen local recurrences (21.3%) have been recorded during a five-year follow-up: 9 after AR and 4 after Miles operation. Nine relapses were among the cases with distal clearance less than 3 cm an eight of these have undergone anterior resections. No recurrence was seen in cases with distal clearance greater than 5 cm. Spread was found in 11 (18%) patients. Five recurrences were recorded all belonging to the group with anterior resection. No statistical difference exists between conservative surgical procedure and abdominal-perineal operation. We have been able to demonstrate only the direct relationship between relapse and Dukes C stage after curative rectal surgery.

Actuarial Analysis↗
PubMed1990

Myelofibrosis with myeloid metaplasia: clinical and haematological parameters predicting survival in a series of 133 patients.

The prognostic value of 12 clinical and haematological parameters, recorded at diagnosis, in myelofibrosis with myeloid metaplasia (MMM) was retrospectively analysed in a consecutive series of 133 patients followed for a minimum of 60 months. Multivariate analysis showed that the following features were associated with a significantly shorter survival: (1) short period of time (less than 13 months) between first symptoms and diagnosis; (2) anaemia (haemoglobin less than 10 g/dl); (3) leucocyte count greater than 12 x 10(9)/l; (4) peripheral blood granulocyte precursors greater than 10%. Age, splenectomy and percentage of peripheral blood metamyelocytes were found significantly to affect survival only from univariate analysis, whereas sex, size of spleen, thrombocytopenia and thrombocytosis were of no prognostic significance. These data suggest that a more intensive chemotherapy might be useful for younger patients with bad prognostic factors at diagnosis.

Adult↗
PubMed1989

Structure and activity of proteins from pathogenic fungi Phytophthora eliciting necrosis and acquired resistance in tobacco.

The phytopathogenic fungi Phytophthora cryptogea and Phytophthora capsici cause systemic leaf necrosis on their non-host tobacco; in culture they release proteins, called cryptogein and capsicein, which elicit similar necrosis. In addition, both proteins protect tobacco against invasion by the pathogen Phytophthora nicotianac, the agent of the tobacco black shank, that is unable to produce such an elicitor. Cryptogein causes visible leaf necrosis starting at about 1 microgram/plant, whereas 50-fold as much capsicein is required for the same reaction. Capsicein induces protection even in near absence of leaf necrosis. The activities of both elicitors are eliminated upon pronase digestion. They are proteins of similar Mr (respectively 10,323 and 10,155) and their complete amino acid sequences were determined. They consist of 98 residues, with some internal repetitions of hexapeptides and heptapeptides. 85% identity was observed between both sequences: only two short terminal regions are heterologous, while the central core is entirely conserved. Secondary structure predictions, hydropathy and flexibility profiles differ only around position 15 and at the C-terminus; these modifications could play a role in the modulation of their biological activities. After a search of the sequence data bases, they appear to be novel proteins.

Algal Proteins↗
PubMed1989

Slowly progressive ischemic stroke as first manifestation of essential thrombocythemia.

We report a case of essential thrombocythemia, the only clinical manifestation of which consisted of neurologic symptoms, including anomic aphasia, tactile and painful hypesthesia in the right hand, headache, and Gerstmann syndrome, with a relatively benign and slowly progressive clinical course. Neuroradiologic examination disclosed a large ischemic area in the left temporoparietal region. Cerebral angiography revealed an occlusion of the cortical branches of the left middle cerebral artery with total sparing of the carotid vessel. These findings are discussed in relation to the possible pathogenetic mechanisms of the vascular occlusion due to abnormal platelet function in essential thrombocythemia.

Adult↗
PubMed1988

Angiotensin stimulation of adrenal fasciculata cells.

In this paper we provide evidence to show that the pathways by which adrenocorticotropic hormone (ACTH) and angiotensin II (AII) stimulate steroidogenesis in bovine fasciculata cells are only partially independent. Both hormones have the same intrinsic activity but a 500-fold higher dose of AII is required to achieve 50% stimulation of steroidogenesis. Whereas ACTH acts by way of cAMP, AII appears to operate through protein kinase C. The phorbol ester, 12-O-tetradecanoylphorbol-13 acetate (TPA), and the calcium ionophore, A23187, each stimulate steroidogenesis and, when added together, act synergistically. To test the relationship between the ACTH and AII pathways, we added the two hormones simultaneously and measured steroid production. When the hormones were present at submaximal concentrations, their effects were additive. At maximal doses, steroid production was 40% above that elicited by either hormone alone. In contrast to the action of AII in the glomerulosa cell where it inhibits ACTH-stimulated cAMP formation, AII causes no inhibition in the fasciculata. Cycloheximide inhibits steroidogenesis stimulated by AII or a mixture of TPA and A23187. Scatchard analysis of the binding of 125I-AII to particulates from adrenal cortical fasciculata indicates the presence of a single class of binding sites (Kd = 0.6 X 10(-8) M). Binding is not inhibited by ACTH. Biotin-containing AII analogs that bind specifically to the particulates have been evaluated as potential tools for avidin-biotin affinity chromatography of the receptor. One of these, [N epsilon-6-(biotinylamido)hexyllys1, Val5] AII, is a promising candidate for receptor isolation.

Adrenal Cortex↗