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Background: Medullary thyroid carcinoma (MTC) is a calcitonin (CT)-producing C-cell tumor. In hereditary cases, a germline RET mutation is found in 98% of families. Because MTC is cured only if intrathyroidal, prophylactic thyroidectomy is recommended in the gene carrier (GC)., Aims: The aim was to determine whether thyroidectomy performed when stimulated CT becomes detectable is as safe as prophylactic thyroidectomy and to identify the serum CT cutoff able to distinguish intrathyroidal from extrathyroidal MTC., Patients: Eighty-four GC were prospectively enrolled; 53 of the 84 underwent total thyroidectomy, one refused surgery, and 30 with normal basal and stimulated CT were under surveillance. The follow-up ranged from 2 to 18 yr., Results: GC operated on for elevated stimulated CT included 27 GC with a positive peak CT at the screening and four cases who became positive after 4 yr. All of them had intrathyroidal MTC and no node metastases; all were cured after a mean follow-up of 7.5 yr. Among those operated on for detectable basal CT, intrathyroidal tumors were found when CT was below 60 pg/ml, whereas either node metastases or larger tumors were observed when CT was above 60 pg/ml. No correlation among serum CT, age, and type of RET mutation was observed. Thirty GC were still biochemically negative at the annual control., Conclusions: The time of thyroidectomy in GC with negative CT could be personalized and safely planned when stimulated CT becomes positive, independent of the type of RET mutation and patient's age. In this series, a basal CT below 60 pg/ml was always associated to an intrathyroidal localization of MTC.

About 30% of hereditary Medullary Thyroid Carcinoma (MTC) have been demonstrated to harbour imbalance between mutant and wild-type RET alleles. We studied the RET copy number alterations (RET CNA) in 65 MTC and their correlation with RET mutation and patients' outcome. Fluorescence in situ Hybridization and Real-time PCR revealed RET CNA in 27.7% MTC but only in a variable percentage of cells. In sporadic MTC, RET CNA were represented by chromosome 10 aneuploidy while in hereditary MTC by RET amplification. A significant higher prevalence of RET CNA was observed in RET mutated MTC (P=0.003). RET CNA was also associated to a poorer outcome (P=0.005). However, the multivariate analysis revealed that only RET mutation and advanced clinical stage correlated with the worst outcome. In conclusion, 30% MTC harbour RET CNA in variable percentage of cells suggesting cell heterogeneity. RET CNA can be considered a poor prognostic factor potentiating the poor prognostic role of RET mutation., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Objective: This study was aimed to demonstrate the clinical benefits of rearranged during transfection (RET) genetic screening in patients with apparently sporadic medullary thyroid cancer (MTC) not only to identify the hereditary nature of the disease in the index case but also to discover family members harbouring the same germline mutations (i.e. gene carriers) who are unaware of their condition., Context: RET genetic screening allowed the identification of germline RET mutations in apparently sporadic MTC resulting in their re-classification as hereditary forms., Patients and Measurements: RET genetic screening was performed in 729 apparently sporadic MTC patients by direct sequencing RET exons 5, 8, 10, 11 and 13-16. Clinical and biochemical evaluation of gene carriers was also performed., Results: We discovered an unsuspected germline RET mutation in 47 of 729 (6·5%) apparently sporadic MTC who were re-classified as hereditary. We found 60 of 146 (41·1%) gene carriers, 35 of whom had biochemical or clinical evidence of MTC. Thirty gene carriers underwent total thyroidectomy and 27 of 30 (90%) were persistently cured after a mean follow-up of 6·0 years. As a further result of RET genetic screening, we observed a significantly higher prevalence of familial medullary thyroid cancer (FMTC) in our series with respect to the largest series of the International RET Consortium (P = 0·0002)., Conclusions: RET genetic screening of patients with apparently sporadic MTC represents a major tool for the preclinical diagnosis and early treatment of unsuspected affected family members and allows the identification of a relevant percentage of hidden FMTC., (© 2011 Blackwell Publishing Ltd.)

Background: Medullary thyroid carcinoma (MTC) is a well-differentiated thyroid tumor that maintains the typical features of C cells. An advanced stage and the presence of lymph node metastases at diagnosis have been demonstrated to be the most important bad prognostic factors. Somatic RET mutations have been found in 40-50% of MTCs. Although a relationship between somatic mutations and bad prognosis has been described, data are controversial and have been performed in small series with short-term follow ups. The aim of this study was to verify the prognostic value of somatic RET mutations in a large series of MTCs with a long follow up., Methods: We studied 100 sporadic MTC patients with a 10.2 yr mean follow-up. RET gene exons 10-11 and 13-16 were analyzed. The correlation between the presence/absence of a somatic RET mutation, clinical/pathological features, and outcome of MTC patients was evaluated., Results: A somatic RET mutation was found in 43 of 100 (43%) sporadic MTCs. The most frequent mutation (34 of 43, 79%) was M918T. RET mutation occurrence was more frequent in larger tumors (P=0.03), and in MTC with node and distant metastases (P<0.0001 and P=0.02, respectively), thus, a significant correlation was found with a more advanced stage at diagnosis (P=0.004). A worse outcome was also significantly correlated with the presence of a somatic RET mutation (P=0.002). Among all prognostic factors found to be correlated with a worse outcome, at multivariate analysis only the advanced stage at diagnosis and the presence of a RET mutation showed an independent correlation (P<0.0001 and P=0.01, respectively). Finally, the survival curves of MTC patients showed a significantly lower percentage of surviving patients in the group with RET mutations (P=0.006)., Conclusions: We demonstrated that the presence of a somatic RET mutation correlates with a worse outcome of MTC patients, not only for the highest probability to have persistence of the disease, but also for a lower survival rate in a long-term follow up. More interestingly, the presence of a somatic RET mutation correlates with the presence of lymph node metastases at diagnosis, which is a known bad prognostic factor for the definitive cure of MTC patients.

Late-onset infections of synthetic vascular grafts (LO-SVGIs) are generally caused by staphylococci that produce a slime polysaccharide and grow as a biofilm on the graft surface. We developed an ELISA to detect serum antibodies against staphylococcal slime polysaccharide antigens (SSPA). Patients with an ongoing staphylococcal LO-SVGI had greater titres of IgM antibodies against SSPA than did patients in other groups. Antibody titres of 0.40 ELISA units (EU) or more, or 0.35 EU or more detected 97% and 100% of staphylococcal LO-SVGIs, respectively, 0% and 2% titre/unit false-positive results. Our findings suggest that such an ELISA represents a sensitive, specific, and non-invasive diagnostic test for staphylococcal LO-SVGIs.

The effect of the type of sugar used as substrate on the susceptibility of Streptococcus mutans to antibiotics was evaluated. Thirty strains, grown in excess of sucrose (s-MIC) and in excess of glucose (g-MIC), were tested for susceptibility to four cephalosporins. About 21% of the strains were sensitive in the presence of sucrose and resistant in the presence of glucose, whereas only 3% of the strains showed the opposite situation. The mean values of the s-MICs of the four cephalosporins were significantly lower than those of the g-MICs. These findings may also be explained by the synthesis, in excess of sucrose, of insoluble glucan by Streptococcus mutans which increases the interbacterial distance and promotes antibiotic diffusion. Given the susceptibility of Streptococcus mutans grown in excess of sucrose to cefotaxime and cefepime, these antibiotics may be used in the primary prevention of infective endocarditis, when subjects predisposed to endocarditis need invasive dental therapy.

It has been clearly established that the inoculum size greatly affects the results of antibiotic susceptibility tests performed in both liquid and solid media in standard laboratory growth conditions (i.e. planktonic). Recently methods were developed to perform antibiotic susceptibility tests on bacteria growing in sessile conditions. The present study investigates the effect of the inoculum size on results obtained by these methods. Results show that the inoculum size does not affect tests performed in sessile conditions. A simple and reliable method is proposed to be applied to routine microbiological laboratory procedures.

The percentage of anaerobic micro-organisms in the subgingival microflora represents a simple microbiological index which not only refers to the state but also the risks of periodontal health. The present study aimed to compare two different methods of calculating this index. The study was performed in 45 subjects with moderate gingivitis provoked by the previous application of dental fixtures anchored to both arches. A sample of subgingival microflora was collected from each patient at the level of the vestibular gingival sulcus of the first upper right molar. This was then vortexed, diluted and inoculated in three series of plates. It was chosen to use Walker's culture medium. The total bacterial count was evaluated by incubating the first series of plates in anaerobiosis; the anaerobic bacterial was calculated by subtracting from the total the of facultative aerobic-anaerobic micro-organisms, which in turn was obtained using two methods: the first (method AE) consisted of incubating another series of plates in aerobiosis; the second (method M) involved incubating the last series of plates in anaerobiosis, and adding metronidazole to the culture medium in a solution of 2.5 mg/l. The plates were then kept at 37 degrees C for seven days. The mean percentage of anaerobic microorganisms, given by the percentage ratio between anaerobic and total, relating to the 45 cases studied, was as follows: using method AE: 57.8 +/- 26.3%, and using method M: 40.2 +/- 27.2%. Both figures come close to that proposed and calculated using a much more sophisticated method by Slots, namely 41.5 +/- 19.2% in the event of gingivitis.(ABSTRACT TRUNCATED AT 250 WORDS)

The reliability of bioluminescence assays which employ the luciferin-luciferase ATP-dependent reaction to evaluate bacterial counts was studied, both in vitro and on urine specimens. Bioluminescence and cultural results for the most common urinary tract pathogens were analyzed. Furthermore, the influence of the culture medium, of the assaying method, and of the phase of growth on bioluminescence readings was studied. Results show that Proteus, Providencia, and Morganella strains are not correctly detected, neither in vitro nor in urine samples, by the standard assaying method. The analysis of assaying parameters demonstrated that some modifications to the extraction procedure of bacterial ATP could improve the reliability of this technique.

Sixteen patients that underwent periodontal regeneration procedures by implantation of Goretex membranes were studied to evaluate the microbiota that colonized membranes. The microbiological follow-up showed that colonization was principally due to opportunist gram-negative glycocalyx-producing bacteria. The comparison of the microbial flora of treated and untreated sites showed the influence of surface characteristics on the quality of the resident microbiota. These findings suggest the necessity for developing efficient prohylactic protocols for these cases.

We found it of interest to try to determine a microbiological parameter for the effects that sub-inhibitory doses of a chemotherapeutic agent may have on bacteria. To this end, the antibacterial activity of nalidixic acid was analyzed and our attention was directed to evidence of the production of beta-lactamase by 60 strains. The tests carried out showed that sub-inhibitory concentrations of nalidixic acid, from 2 to 64 times lower than the MIC (minimum inhibitory concentrations), were able to inhibit production of penicillinases in the 14 strains of Staphylococcus spp. tested, while only in 7 of the 21 strains of Gram-negative bacteria. Strains from our collection of beta-lactamase producing bacteria were analyzed, and our results confirmed that nalidixic acid inhibits plasmidic and chromosomic beta-lactamases.

The antimicrobial activities of nalidixic acid-cephalexin (ratio 1:1) and cinoxacin-cefadroxil (ratio 1:2) combinations have been evaluated against 396 clinical isolates; many of them were nalidixic acid- or cinoxacin-resistant organisms (MIC greater than or equal to 100 micrograms/ml). We have also tested the nalidixic acid-amoxicillin combination (ratio 1:1) against 225 amoxicillin-resistant bacterial strains (MIC greater than or equal to 800 micrograms/ml). Synergy was found for 62-70% of the Enterobacteriaceae and nonfermenter bacilli tested and for 85-92% of the gram-positive bacterial strains. The 225 clinical isolates resistant to amoxicillin (MIC greater than or equal to 800 micrograms/ml) were synergistically inhibited by the nalidixic acid-amoxicillin combination.

The validity of nonsimultaneous association of penicillinase-sensitive beta-lactam antibiotics with halogenated isoxazolylpenicillins was tested in various Enterobacteriaceae strains. With several bacterial strains, expecially if producers of beta-lactamase type IV, exposure of either the bacterial suspensions of the brothsupernatant to the isoxazolylpenicillins appears both in vivo and in vitro to reduce the extent of subsequent hydrolysis of penicillinase-sensitive beta-lactam antibiotics.

The antibacterial activity of 6 antibiotics towards 10 gram-positive and 6 gram-negative glycocalyx-producing strains, has been evaluated by employing a method which partially simulates the in vivo colonization of prosthetic devices. The results showed that routine antibiotic sensitivity tests are not predictive about the response of the glycocalyx-embedded bacteria, and that prophylaxis may be useful with ofloxacin and clindamycin, before placing a prosthetic device. Once bacterial colonization had already occurred, however, none of the tested antibiotics was able to eradicate the sessile bacterial form. The minimum bactericidal concentration (MBC) values, indeed, were much higher than those determined on the planktonic form, and were much higher than serum and tissue levels that can be reached in vivo.

Nalidixic acid and two recently synthetized 4-quinolones eliminated F'lac and R-plasmids from E. coli at concentrations of one half or one quarter of the minimum inhibitory concentration (MIC). Two of the three plasmids tested were cured by all derivatives, although with different frequencies. Pefloxacin was the most effective compound compared with the other quinolones and nalidixic acid the least active.

Four fluoroquinolones (norfloxacin, ciprofloxacin, ofloxacin, and pefloxacin) were compared with nalidixic acid for their inhibitory effect on conjugal plasmid transfer. The inhibition was observed in mating experiments using various combinations of drugs at subinhibitory concentrations and 3 different plasmids in the E. coli k12 genetic background. Fluoroquinolones inhibited plasmid transfer to a greater extent than nalidixic acid. Ofloxacin and pefloxacin were consistently the most active agents, causing 90 to 100% inhibition of plasmid transfer in all mating systems studied.

We found that nalidixic acid is a good inhibitor of conjugal transfer of R-plasmids and that related compounds show the same properties. We investigated recently synthetized quinolinic molecules. The inhibition was not due to bacterial activity of the compounds against donors, recipients or R transconjugants; in fact, the drug concentrations were twice or four times lower than the M.I.C. values. The new molecules showed a marked inhibitory effect in various R-mating experiments.

The microbiological properties of cephapirin, a new semisynthetis cephalosporin, have been studied. This antibiotic, if compared with ampicillin, shows a greater activity against gram positive bacteria, a lack of sensitivity to staphlococcal beta-lactamase, and a lower sensitivity to those produced by gram-negative bacteria. Useful therapeutic of cephapirin levels can be detected in human serum 6 h after administration of 500 and 1,000 mg parenterally.

On the premise that a microorganism is sensitive or resistant to a chemoantibiotic according to it's concentrations in biological fluids and tissues, the A. examines those methods available in chemoantibiotic titration such as chemical, enzymatic, radio-immunologic, turbidimetric, potentiometric and agar-diffusion methods. By further evaluating the limits and capacities of these different methods, the A. describes in larger detail the agar-diffusion method which is considered more sensitive, practical and efficient. A brief report is made on the possibility of measuring antibiotic association.