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Biomedical subjects

P Nicoletti

Publications and source records attributed to P Nicoletti.

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

A homogeneous fluorescence polarization assay for detection of antibody to Brucella abortus.

A homogeneous fluorescence polarization (FP) assay (FPA) was developed for detection of antibody in bovine sera to Brucella abortus. The assay used O-polysaccharide prepared from B. abortus lipopolysaccharide in the molecular weight range of 20-30 kDa which was conjugated with fluorescein isothiocyanate and used as a tracer. Fluorescence polarization was measured with a FPM-1 fluorescence polarization analyzer. Sample (20 microliters) was added to 2.0 ml of diluent buffer at ambient temperature. A serum blank reading was taken and tracer (10 microliters) to yield approx. 1.5 nM fluorescein equivalents was added. The FP of the tracer was determined after a period of greater than 2 min. A positive reaction was indicated by a significant elevation of the FP reading over the negative control. In a blind study, 9480 bovine sera were tested in addition to sets of four controls which were included with each lot of 100 samples tested. The controls were a strong positive, a weak positive, a negative and a serum derived from a B. abortus strain 19 vaccinated cow. Test sera included 8669 sera from Canadian cattle which were negative by routine serological tests, 561 sera from cows from which B. abortus had been isolated either from tissues or milk and 250 sera from cattle previously vaccinated with B. abortus strain 19 at various times. One lot of O-polysaccharide tracer was used for all tests. The initial cut-off for negative samples in the fluorescence polarization assay was set at 107.2 mP. This resulted in a sensitivity estimate of 98.1 +/- 1.1% and the specificity was 99.8 +/- 0.09%. After decoding the samples and retesting false positive and negative reactions, the sensitivity estimate was 98.5 +/- 1.0% and the specificity was 100%. It became evident that the initial cut-off value was set too high and, using ROC analysis, a cut-off of 90 mP increased the sensitivity to 99.02% while the specificity decreased to 99.96%. Of the 250 sera from vaccinated cattle, 248 were negative giving a point specificity value of 99.2%.

Animals↗
PubMed1995

In vitro activity of MDL 62,879 against gram-positive bacteria and Bacteroides species.

The new thiazolyl peptide antibiotic MDL 62,879 (GE2270 A) showed excellent in vitro activity in testing against staphylococci and streptococci, with MIC90s ranging from 0.23 to 0.9 mg/l. It was very active against Clostridium difficile and Propionibacterium acnes (MIC90 0.06 mg/l in each case) and had variable activity against Bacteroides spp. MDL 62,879 had exceptionally good activity against Enterococcus faecalis, including against a collection of high-level aminoglycoside-resistant isolates where it had an MIC90 of 0.047. The antibiotic was bacteriostatic for enterococcal isolates but bactericidal for a methicillin-resistant isolate of Staphylococcus aureus.

Anti-Bacterial Agents↗
PubMed1995

Improved competitive enzyme immunoassay for the diagnosis of bovine brucellosis.

A modification of the competitive enzyme-linked immunosorbent assay (C-ELISA) for differentiating the antibody response of cattle vaccinated with Brucella abortus strain 19 and B. abortus infected cattle is described. This assay utilizes lipopolysaccharide as the antigen, immobilized on a polystyrene matrix, and a monoclonal antibody (M84) with specificity for an epitope of the O-polysaccharide. A goat anti-mouse IgG antibody-enzyme conjugate is used for detection. The specificity of the modified assay was 99.7% when 1446 sera from brucellosis free herds were tested and it correctly identified 636 sera from B. abortus infected cattle as positive, using a cut-off of 30% inhibition, for a sensitivity estimate of 100%. No reactions were noted among 261 sera from vaccinated cattle. However, in testing 1147 sera that gave positive reactions in the buffered plate antigen test, the indirect ELISA, the complement fixation test or a combination of these tests from the serum bank, 31 gave positive reactions. Twenty-seven of the 31 sera originated from recently vaccinated cattle. The overall specificity for sera from vaccinated cattle was 97.3%. Because of the sensitivity and specificity of this procedure and its ease of performance, it would be a reasonable alternative as a single assay for serological diagnosis of brucellosis.

Animals↗
PubMed1995

Epirubicin + G-CSF as peripheral blood progenitor cells (PBPC) mobilising agents in breast cancer patients.

BACKGROUND: In an attempt to mobilise peripheral blood progenitor cells (PBPC) from patients with breast cancer, Epirubicin supported with G-CSF was tested. Another aim of the study was also to optimize the procedure so that the number of leukapheresis procedures could be reduced. These cells were subsequently reinfused as hematologic rescue after high-dose chemotherapy programs. PATIENTS AND METHODS: Twenty-nine patients received Epirubicin 150 mg/sqm + G-CSF at the dose of 5 micro/kg/bw s.c. daily, starting 24 hours after chemotherapy. Twelve had metastatic, eight inflammatory or locally advanced disease, and nine were treated in an adjuvant setting. RESULTS: The median numbers of CD34+ cells and CFU-GM collected were 12.9 x 106/kg/bw and 111.7 x 10(4)/kg/bw, respectively. The mean number of leukapheresis procedures per patient was 1.8 +/- 0.3 (range 1-3), and the mean day of the first procedure was the tenth +/- 1 (range 8-13) after Epirubicin. The minimum required target for one high-dose procedure was collected in a single leukapheresis in 13 patients. Moreover, in 9 cases one procedure was adequate for two high-dose courses (i.e. > or = 10 x 10(6)/kg/bw CD34+ cells). Response to Epirubicin was evaluable in 14/20 cases, with a response rate of 50%. CONCLUSIONS: Epirubicin delivered at 150 mg/sqm is a very effective mobilising agent for breast cancer patients; to ameliorate the response rate other active drug(s) should be added.

Adult↗
PubMed1994

The use of divalent cation chelating agents (EDTA/EGTA) to reduce non-specific serum protein interaction in enzyme immunoassay.

An indirect enzyme immunoassay (ELISA) for detection of bovine antibody to Brucella abortus was modified by the addition of divalent chelating agents to the serum diluent. This addition resulted in an increase in specificity from 96.0% in the regular assay to 99.4% in the modified procedure. Of the 15,715 sera initially tested by the indirect ELISA, 691 that had given positive reactions were selected for retesting in the indirect ELISA with EDTA/EGTA added. The buffered plate antigen test (BPAT) correctly identified 98.6% of the samples as negative. The addition of chelating agents did not alter the sensitivity of the indirect ELISA, which correctly classified 609 sera from animals from which B. abortus had been isolated as positive. The sensitivity of the BPAT was 97.8%.

Agglutination Tests↗
PubMed1993

Comparison of enzyme-labeled immunosorbent assay and particle concentration fluorescence immunoassay with standard serologic methods and bacteriologic culture for detection of Brucella sp-infected cows in herds with brucellosis.

Bacteriologic culture of udder secretions and card, rivanol, and complement fixation tests for detection of brucellosis were performed on samples from 828 cows vaccinated with strain 19 in herds with brucellosis. An ELISA and a particle concentration fluorescence immunoassay were performed on sera from 560 and 569 cows, respectively. A field strain of Brucella abortus or strain 19 was isolated from 278 cows. The ELISA and the card test had high sensitivity, but low specificity. Data suggested that there is no advantage to using primary binding assays rather than the simple buffered antigen agglutination procedures to detect cows infected with a field strain of B abortus.

Agglutination Tests↗
PubMed1993

Urinary tract infections in the city of Florence: epidemiological considerations over a twenty-year period.

Our study of significant bacteriurias indicated that the worldwide shift in the etiology of infections also holds true for the Florence area. In a twenty-year period (1970-1990), we noted a decreased frequency of Gram-negative bacilli, particularly of the family Enterobacteriaceae, and a significant increase of Gram-positive cocci in urinary patients. This finding was observed both in hospital and in community-acquired cases in the male sex and only in nosocomial bacteriurias in the female sex. There was a reduced isolation of "classic" urinary pathogens such as Proteus mirabilis: its prevalence in hospital-acquired urinary tract infection (UTI) decreased from 16% in 1970 to 5% in 1990 both in males and in females. On the other hand, we noted an increase of "difficult" microorganisms such as enterococci and methicillin-resistant staphylococci, particularly in the male sex; in 1970 enterococci were occasionally isolated in males both from hospital and from community-acquired UTIs (3% and 5%, respectively), whereas in 1990, on the contrary, they were encountered much more frequently (19% in both cases).

Bacteriuria↗
PubMed1993

In vitro brodimoprim activity on nosocomial bacterial strains.

The activity of brodimoprim, a new diaminopyrimidine, against 385 recent clinical isolates of Gram-positive cocci and Gram-negative bacilli was in vitro tested by the disk sensitivity test (DST) of Bauer et al. with disk concentration of 2.5 micrograms and by the agar dilution method. The postantibiotic effect (PAE) and the postantibiotic leukocyte killing enhancement (PALE) were determined on selected pathogens. The MICs were determined with Müller Hinton II agar (BD) and a multipoint inoculator (Denley A 400); thymidine phosphorylase (0.08 U/ml) was added to the test agar. Brodimoprim was very active against S. pyogenes (27), Salmonella sp. (30), methicillin susceptible S. aureus (36) and E. faecalis (34). The geometric means (GM) of MICs ranged from 0.08 to 0.63 and % of resistance from 0.0 to 14.7. Higher MICs (GM from 1.02 to 2.67) were shown against Citrobacter sp. (32), Klebsiella sp. (27), E. coli (36), methicillin-resistant S. aureus (33), Enterobacter sp. (32), Proteus sp. (31) and methicillin-susceptible coagulase negative staphylococci (34); resistant strains ranged from 18.7 to 41.2%. The in vitro activity against methicillin-resistant coagulase-negative staphylococci (33) (72.7% of resistance to brodimoprim) was very low. Regression analysis, obtained correlating the results of MICs with those of agar diffusion, shows that the resistant strains have a diameter less than 11 mm, the intermediate ones a diameter of 11-13 mm and susceptible strains a diameter greater than 13 mm. The PAE was determined using the Abbott AVANTAGE system. Strains were exposed to brodimoprim (1/4 x MIC - 4 x MIC range) for 2 or 6 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Cross Infection↗
PubMed1992

An evaluation of serologic tests used to diagnose brucellosis in buffaloes (Bubalus bubalis).

Five serologic procedures were evaluated in buffaloes and results compared with cultures of 64 udder secretion specimens. The rivanol test was superior to all other methods in specificity. The card, rivanol and complement fixation tests identified all infected cows. Many sera had complement fixing antibodies while agglutinins were absent. It was concluded that these were false positive results. A new procedure, the particle concentration fluorescence immunoassay, was a sensitive screening test but lacked specificity. On a limited number of samples, the tube agglutination test lacked sensitivity and was not a very useful procedure for the diagnosis of brucellosis. All 18 isolates of Brucella abortus were biovar 1.

Agglutination Tests↗
PubMed1992

Control of brucellosis in Kuwait by vaccination of cattle, sheep and goats with Brucella abortus strain 19 or Brucella melitensis strain Rev. 1.

In Kuwait, approximately 12,000 dairy cows were vaccinated with a reduced dose of 3 x 10(9) Brucella abortus strain 19 and approximately 350,000 sexually mature sheep and goats with a reduced dose of 10(7) B. melitensis strain Rev. 1. Using the criteria of prevaccinal and postvaccinal incidences of antibodies, abortions, and human cases of brucellosis, the programme was very successful. Widespread vaccination of adult animals is the most effective method of controlling brucellosis among cattle, sheep and goats in many countries.

Animals↗
PubMed1990

Evaluation of serologic and cellular immune responses of cattle to a nonlipopolysaccharide antigen from Brucella abortus.

Cows naturally infected with Brucella abortus developed antibody (Ab) responses to a nonlipopolysaccharide antigen (NLA) purified from B abortus strain 1119-3. Sera from strain 19-vaccinated cows did not have detectable amounts of Ab. Weak lymphoproliferative responses to NLA were observed in blood mononuclear cell suspensions obtained from infected cows. There was no evidence of NLA-specific lymphoproliferation in cell suspensions from healthy cows. Nonlipopolysaccharide antigen binding to bovine blood mononuclear cells was observed by antigen-consumption assays and direct binding of radiolabeled antigen. Cells from infected cows bound less NLA than did cells from healthy cows when assays were conducted with intact blood mononuclear cell preparations (monocytes plus lymphocytes). Monocytes obtained from any group did not bind NLA. Purified B lymphocytes from infected and healthy vaccinated cows bound about 3 times more NLA than did T lymphocytes, but there were no apparent differences between the 2 groups in extent of binding. Results of the study indicate that bovine lymphocytes have binding sites for a NLA purified from B abortus strain 1119-3.

Animals↗
PubMed1990

[Iron deficiency in an area of Bolivia and high prevalence of intestinal helminthiasis].

Between November and December 1987, 201 subjects from three communities of the Cordillera Province, Santa Cruz Department, South-East Bolivia (Camiri, Boyuibe, and Gutierrez) were examined for serum iron levels. Sixty-three (31.3%) were iron deficient. There were no significant differences between males and females (37.2% and 26.9%, respectively) and among the three localities studied. Iron deficiency was highest in the 3- to 9-year-old age group and lowest in the 30- to 39-year-old group. Considering the prevalence in the same localities of infections by hookworms, Trichuris trichiura, Strongyloides stercoralis, and Trichostrongylus, it is suggested that hookworms and possibly other intestinal parasites may be an important cause of the observed iron deficiency.

Adolescent↗
PubMed1990

Vaccination against Brucella.

Vaccination has played an enormous role in reducing brucellosis in many countries. It is certain to continue to be the preeminent factor in control of the disease in others. The search for an ideal vaccine continues. Live vaccines have proved to be superior to inactivated products. They are effective, inexpensive, and immunity is more persistent. The disadvantages of postvaccinal antibodies can be minimized by reduction of previously recommended doses and through use of supplemental diagnostic tests. These procedures now make entire population vaccination of great practical significance with many advantages over limited use of the strains 19 and Rev. 1. Adult animal vaccination should be much more extensive in many countries. A live B. suis strain 2 vaccine developed in China deserves much additional evaluation, including use in swine, for which no satisfactory vaccine exists. It is generally agreed that cell-mediated responses are the dominant aspect of immunogenesis. However, the correlates that have frequently been used--dermal hypersensitivity and lymphocyte stimulation in vitro--appear to be poor indices of cell-mediated immunity in brucellosis. Many studies have shown that postvaccinal antibodies do not predict subsequent immunity. There is a great need for simple in vivo or in vitro methods to measure CMI. While vaccination of humans may be useful in control of brucellosis in some high-risk occupations, the ultimate success is dependent upon reduction of this very important zoonosis in natural hosts. This is most effectively accomplished by widespread use of vaccination.

Animals↗
PubMed1989

Efficacy of various treatment regimens, using liposomal streptomycin in cows with brucellosis.

Thirty cows naturally infected with Brucella abortus were treated by various routes, using free or liposomal streptomycin or a combination of liposomal streptomycin and a long-acting oxytetracycline preparation. Of 21 cows treated with liposomal streptomycin alone, 3 (14%) were culture negative and 3 had 10 or fewer bacterial colonies isolated from tissues obtained at necropsy. Thirteen (62%) cows continued to shed organisms in udder secretions and were considered treatment failures. Of 9 cows that were given a combination of liposomal streptomycin and long-acting oxytetracycline, 5 (56%) were cured, 3 had 10 or fewer colonies on culture plates of tissue after necropsy and only 1 continued to shed B abortus in udder secretions after treatment. Eleven cows were given streptomycin liposomes by intramammary infusion with or without IM administration of long-acting oxytetracycline. The most effective regimen consisted of 2 intramammary infusions of streptomycin liposomes and 2 doses of oxytetracycline administered IM. Of 5 cows treated thusly, 2 were cured and all others had fewer than 10 B abortus colonies isolated from tissues obtained at necropsy.

Animals↗
PubMed1989

Prevalence of antibody to hepatitis A virus in the Santa Cruz region of Bolivia.

Several epidemiological studies have shown the worldwide distribution of hepatitis A with the highest prevalence of anti-HAV antibodies in developing countries (Papaevangelou 1984). There is no information about the epidemiology of hepatitis A in Bolivia. The goal of this study was to evaluate the anti-HAV antibody prevalence in the Santa Cruz region, southeastern Bolivia.

Age Factors↗