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Biomedical subjects

G Scalise

Publications and source records attributed to G Scalise.

At least 91 records · Page 5Linked to original sources

Prevalence and antifungal susceptibility of vaginal yeasts in outpatients attending a gynecological center in Ancona, Italy.

Between February 1993 and May 1994 we studied the prevalence of fungal vulvovaginitis among women attending the Obstetric and Gynecology Clinic of the University of Ancona. Out of the 222 patients, 18 (8.2%) women had symptomatic vaginitis and 24 (10.8%) were carriers. Candida albicans was the species most frequently isolated (44.2%), followed by Torulopsis glabrata (28%) and Saccharomyces cerevisiae (16.2%), from symptomatic and carrier patients. The activity of acid proteinase was determined for C. albicans isolated from both symptomatic and carrier patients. All 13 carriers showed low activity for aspartyl proteinase (score 1+), while 5 of 6 symptomatic patients showed higher activity (score 2+), with a significant difference (p = 0.026). In general, isolates of T. glabrata and S. cerevisiae were less susceptible in vitro to fluconazole than isolates of C. albicans. We did not find any differences in fluconazole MIC results among the C. albicans strains isolated from symptomatic and carrier patients. On the other hand, the fluconazole MICs of T. glabrata and S. cerevisiae isolates showed statistically significant differences between symptomatic and carrier patients (p = 0.009 and p = 0.000, respectively). The differences in proteinase secretion between the isolates from symptomatic and carrier patients suggest a correlation between proteinase production and vaginal candidiasis caused by C. albicans. Torulopsis glabrata, however, was found to be the most common causative agent of vaginitis (7 out 19 episodes), followed by C. albicans (6 out of 19 episodes). Due to the varying patterns of antifungal susceptibility, mainly to fluconazole for the yeast isolates considered in this study, an in vitro susceptibility testing program might be useful for monitoring the outcome of this infection.

Adult↗

In-vitro activity of atovaquone, sulphamethoxazole and dapsone alone and combined with inhibitors of dihydrofolate reductase and macrolides against Pneumocystis carinii.

The anti-Pneumocystis carinii activity of atovaquone, dapsone and sulphamethoxazole alone and combined with dihydrofolate reductase (DHFR) inhibitors and macrolides was investigated against five clinical isolates of P. carinii. The susceptibility tests were performed by inoculation of the organisms on to cell monolayer and parasite count after 72 h incubation at 37 degrees C. Culture plates were added to Dulbecco's modified Eagle's medium containing serial dilutions of atovaquone, dapsone and sulphamethoxazole alone or in combination with diaveridine, pyrimethamine, trimethoprim, azithromycin, clarithromycin and roxithromycin. Atovaquone, dapsone and sulphamethoxazole were found to be effective at levels well below the concentrations that could be achieved clinically, while DHFR inhibitors were shown to combine effectively with dapsone and sulphamethoxazole. No synergy could be demonstrated between atovaquone and DHFR inhibitors or macrolides. A mild synergic effect was noted when macrolides were combined with dapsone and sulphamethoxazole. Pyrimethamine (0.5 mg/L) combined with dapsone and trimethoprim (0.5 mg/L) combined with sulphamethoxazole exerted the strongest inhibitory effect.

Anti-Bacterial Agents↗

In-vitro activity of topoisomerase inhibitors against Pneumocystis carinii.

The activity of eight topoisomerase inhibitors was investigated against five clinical isolates of Pneumocystis carinii. Susceptibility tests were performed by inoculation of the organisms on to a cell monolayer and parasites were counted after 72 h incubation at 37 degrees C. Culture plates were added with Dulbecco's modified Eagle's medium containing serial dilutions of lomefloxacin, norfloxacin, ofloxacin, pefloxacin, rufloxacin, camptothecin, amsacrine and etoposide. Atovaquone, pentamide isethionate and co-trimoxazole were used as control drugs. Etoposide gave inhibition comparable to that observed with atovaquone. Poor activity was demonstrated by pefloxacin, while the other topoisomerase inhibitors had no significant effect.

Enzyme Inhibitors↗

In vitro activities of terbinafine in combination with fluconazole and itraconazole against isolates of Candida albicans with reduced susceptibility to azoles.

A checkerboard microdilution method was applied to study the in vitro interaction of terbinafine with either fluconazole and itraconazole against 30 strains of Candida albicans. Synergy was observed in 40% of the terbinafine-fluconazole interactions and in 43% of the terbinafine-itraconazole interactions, while antagonism was not observed. Even when only additivity was achieved, the combinations still showed beneficial effects since at least twofold reductions in the MICs of both drugs were found in 100% of the terbinafine-fluconazole interactions and in 76% of the terbinafine-itraconazole interactions.

Antifungal Agents↗

A randomized trial (ISS 901) of switching to didanosine versus continued zidovudine after the diagnosis of AIDS.

Although the efficacy of switching from zidovudine (AZT) to didanosine (ddI) has already been evaluated in controlled studies, prior investigations were not specifically designed to evaluate this issue in patients with acquired immune deficiency syndrome (AIDS). This open, randomized, multicenter study (ISS 901) was designed to evaluate the clinical benefit in patients with AIDS of switching to ddI after 6-18 months of AZT and no major intolerance. Patients were randomized to continue AZT, maintaining the current dosage at randomization (n = 79), or to receive ddI (n = 80) at the dosage of 375 mg and 250 mg b.i.d. for body weight > 60 and < or = 60 kg, respectively. Primary efficacy measures were survival and time to new AIDS-defining events, analyzed by the intent-to-treat approach. The two groups were comparable for baseline characteristics, follow-up (15 months), and time spent on allocated treatment. At the end of the study, 104 patients (48 AZT, 56 ddI) had died and 90 had at least one new AIDS-defining event (44 AZT, 46 ddI). Kaplan-Meier estimates of survival and of time to first new AIDS-defining event showed no differences between the treatment groups. No differences were detected in other efficacy measurements (p24 antigenemia, CD4+ count, Karnofsky score, and body weight), occurrence of severe toxicities, and treatment modifications. Pancreatitis occurred only in ddI-treated patients (6%). In our population of patients with advanced disease, switching from AZT to ddI did not produce apparent benefits, suggesting that application of this strategy earlier in the course of human immunodeficiency virus disease should be considered.

Acquired Immunodeficiency Syndrome↗

In-vitro activity of macrolides alone and in combination with artemisin, atovaquone, dapsone, minocycline or pyrimethamine against Cryptosporidium parvum.

The anticryptosporidial activity of four macrolides alone and in combination with other antimicrobial agents was investigated against ten clinical isolates of Cryptosporidium parvum recovered from stools of AIDS patients. The susceptibility tests were performed by inoculation of the protozoa on to cell monolayers and determining the parasite count after 72 h incubation at 37 degrees C. The culture medium was supplemented with Dulbecco's modified Eagle's medium containing serial dilutions of azithromycin, clarithromycin, roxithromycin, spiramycin, alone or in combination with artemisin, atovaquone, dapsone, minocycline or pyrimethamine. Most of the agents had an inhibitory effect on parasite growth, but only at high concentrations. No agent was able to inhibit parasite growth completely, even at the highest concentrations used. The more effective agents, azithromycin, clarithromycin, roxithromycin, minocycline and pyrimethamine, produced no more than a 13.1-27.8% reduction in oocyst count and no more than a 15.1-35.7% in schizont count. Positive interaction was clearly demonstrated when macrolides were tested in combination with minocycline or pyrimethamine.

Acquired Immunodeficiency Syndrome↗

Variation in fluconazole efficacy for Candida albicans strains sequentially isolated from oral cavities of patients with AIDS in an experimental murine candidiasis model.

Four strains of Candida albicans, isolated from two patients with AIDS who had undergone prolonged fluconazole therapy for oral candidiasis, were studied in a model of disseminated murine candidiasis. Pre- and posttreatment isolates from each patient were genetically related, and the fluconazole MICs for the strains had increased significantly, from 0.25 to 32 micrograms/ml for the strains isolated from patient 1 and from 1.0 to 16 micrograms/ml for the strains isolated from patient 2. Mice were infected intravenously and were treated orally with fluconazole. For survival studies, mice were treated from day 1 to day 10 postinfection and were observed through day 30. The fluconazole dosages were as follows: 0.25, 0.5, 1.0, and 5.0 mg/kg of body weight twice a day. For tissue burden studies, two groups of mice (each group received fluconazole at 0.25 or 5.0 mg/kg) were treated from day 1 to day 7 and were sacrificed 1 day later for quantitative tissue cultures of the spleen and both kidneys. For pretreatment isolates from both patients, all fluconazole dosing regimens were effective at prolonging survival compared with the survival of the control groups. For posttreatment isolates, only fluconazole at 5.0 mg/kg was effective at prolonging survival. Both fluconazole dosing regimens used in the tissue burden studies significantly reduced the counts of the pretreatment isolate from patient 1 in the spleen and kidney, while fluconazole at 5.0 mg/kg was effective at reducing the counts of the posttreatment isolate. For both isolates from patient 2, only fluconazole at 5.0 mg/kg was effective at reducing the counts in the spleen and kidney. The study indicates that C. albicans mutation to resistance to fluconazole may play a critical role in fluconazole-refractory oral candidiasis in AIDS patients.

Acquired Immunodeficiency Syndrome↗

Benefit of oral zinc supplementation as an adjunct to zidovudine (AZT) therapy against opportunistic infections in AIDS.

Zinc is perhaps the most important trace element for immune function. Congenital or acquired zinc deficiencies are associated with immune abnormalities and increased susceptibility to infectious diseases. AIDS subjects suffer from reduced zinc bioavailability, more severe in stage IV than in stage III. Such zinc deficiency causes, among other effects, a profound reduction in the biological activity of one of the thymic hormones, thymulin (zinc-facteur-timique-serique, ZnFTS). With these premises, zinc sulphate was administered orally at a daily dose of 200 mg for 30 days to AZT-treated stage III subjects with generalized lymphadenopathy (17 subjects) and stage IV subgroup C1 (12 subjects) AIDS patients. 18 stage III subjects with generalized lymphoadenopathy and 10 stage IV subgroup C1 subjects treated only with AZT served as controls. Zinc sulphate supplementation of stage III and in stage IV C1 patients was followed by an increase or a stabilization in the body weight and an increase of the number of CD4+ cells and the plasma level of active zinc-bound thymulin. The frequency of opportunistic infectious episodes in the 24 months following entry into the study was reduced after zinc supplementation in stage IV C1 subjects (11 infections vs 25 in controls) and delayed in stage III zinc-treated subjects (1 infection/24 months vs 13 infections/24 months in controls). The effect of zinc on opportunistic infections is restricted to infections due to Pneumocystis carinii and Candida, whereas no variations have been observed in the frequencies of cytomegalovirus and toxoplasma infections. These data may support the benefit of zinc as an adjunct to AZT therapy in AIDS pathology.

AIDS-Related Opportunistic Infections↗

Electrophoretic karyotype and in vitro antifungal susceptibility of Cryptococcus neoformans isolates from AIDS patients.

Electrophoretic karyotype (EK) was used to type 13 clinical isolates of Cryptococcus neoformans from eight AIDS patients. All of the isolates were also tested for their in vitro susceptibilities to fluconazole, itraconazole, D0870, flucytosine, and amphotericin B by a broth macrodilution technique performed according to the National Committee for Clinical Laboratory Standards recommendations. Although all strains were isolated from a limited geographic area, DNA typing showed a wide genetic variation in this group of patients, yielding seven different patterns. Two patients in whom C. neoformans was isolated in the same time period shared similar EK profiles, suggesting the possibility of cross-infection. In three patients, sequential isolates were evaluated: in two of them, EK analysis showed the persistence of the same genotype throughout the infection, whereas from the third, two isolates of C. neoformans with two different DNA profiles were obtained. Despite the small number of strains considered in this study, our susceptibility data indicate that C. neoformans isolates are very susceptible to the new triazoles.

AIDS-Related Opportunistic Infections↗

DNA subtypes and fluconazole susceptibilities of Candida albicans isolates from the oral cavities of patients with AIDS.

Sixty-two Candida albicans isolates from the oral cavities of 28 patients with AIDS who were receiving fluconazole therapy were typed by restriction endonuclease analysis followed by pulsed-field gel electrophoresis; these isolates were then tested for fluconazole susceptibility by a standard broth dilution method. Sequential isolates (range, 2-4) were evaluated for 22 patients; only one isolate was evaluated for six patients. DNA subtyping revealed a total of 37 different DNA subtypes. Twelve (54.5%) of 22 patients with multiple episodes of oropharyngeal candidiasis were infected with a single DNA subtype throughout the observation period. Ten (45.5%) of 22 patients with multiple episodes of oropharyngeal candidiasis were infected with two or three DNA subtypes during the observation period. In vitro susceptibility tests revealed that MICs of fluconazole ranged from < or = 0.125 microgram/mL to 64 micrograms/mL, with an MIC50 of 0.5 microgram/mL and an MIC90 of 4 micrograms/mL. A significant increase in the MICs (fourfold or greater) of fluconazole for sequential C. albicans isolates was found for 66.6% of the patients infected with a single DNA subtype and for 50% of the patients infected with multiple DNA subtypes. Despite a limited number of patients and isolates, our data suggest that C. albicans isolates that are susceptible to fluconazole at MICs of > or = 8 micrograms/mL in vitro will be less susceptible in vivo to standard doses (100-200 mg/d) of this drug.

AIDS-Related Opportunistic Infections↗

Transmission of fluconazole-resistant Candida albicans between patients with AIDS and oropharyngeal candidiasis documented by pulsed-field gel electrophoresis.

Electrophoretic karyotype and restriction endonuclease analysis of genomic DNA were used for the typing of nine isolates of Candida albicans from the oral cavities of two patients with AIDS--a husband and wife--whose infections became resistant to treatment with fluconazole (400 mg/d). The in vitro susceptibilities of sequential isolates to fluconazole and two other triazoles, itraconazole and the investigational drug D0870, were also evaluated. DNA analysis showed that the isolates responsible for fluconazole-resistant episodes of oropharyngeal candidiasis in the two patients were genetically related. In vitro susceptibility to fluconazole correlated well with clinical outcome. Although the minimal inhibitory concentrations of itraconazole and D0870 for fluconazole-resistant isolates were higher than those for fluconazole-susceptible isolates, both of the former triazoles exhibited good in vitro activity against the isolates tested.

AIDS-Related Opportunistic Infections↗

Quantitative molecular monitoring of human immunodeficiency virus type 1 activity during therapy with specific antiretroviral compounds.

Methods for the absolute quantitation of nucleic acids present in small amounts in biological samples (competitive PCR and competitive reverse transcription PCR) were applied to the direct monitoring of specific anti-human immunodeficiency virus type 1 (HIV-1) therapy. With these techniques, different parameters of HIV-1 activity (including genomic RNA copy numbers in plasma, proviral and late transcript copy numbers in peripheral blood lymphocytes, and mean transcriptional activity per each HIV-1 provirus) were monitored during therapy with azidothymidine or ddI. In most of these treated patients, a direct response to the antiretroviral compounds employed was detected during the first few weeks of treatment, as documented by a fast decrease of all molecular indexes of HIV-1 activity. However, residual viral replication (albeit at minimal levels) was documented during therapy in all subjects monitored in this study. In a minority of the patients under study (3 of 12), the drug-dependent viral inhibition was maintained throughout the observation time (213 to 791 days), but in 9 patients a rebound in viremia level was detected during therapy with competitive reverse transcription PCR. Sequencing analysis of a portion of the HIV-1 gene pol from cell-free virions showed that circulating viral variants bearing at least two mutations compatible with azidothymidine or ddI resistance were detectable in the patients who exhibited a rebound in cell-free HIV-1 genomic RNA copy numbers in plasma but not in one patient who maintained (for 455 days) lowered levels of viral load during ddI treatment.

Amino Acid Sequence↗