[Expression of stem cell markers on fetal and tumoral human liver cells in primary culture]. / Expresia de markeri ai celulelor stem pe celulele în cultura primara izolate din ficatul fetal si ficatul tumoral uman.

Hepatic stem cells can be identified by the expression of putative markers such as CD117 (c-kit), CD90 (Thy-1), CD34, and HLA-DR. We have identified populations expressing these markers in both fetal and tumoral human liver by flow cytometry, using monoclonal antibodies against CD90, CD117, CD34, and HLA-DR. In tumoral liver CD117+/CD90+ cells were found in decreasing number from the neoplastic (2.48 +/- 0.67) and peritumoral region (0.88 +/- 0.12) to the area of para-tumoral (normal) parenchyma (0.13 +/- 0.04). The CD117+/CD34+ cells showed the following distribution: 0.35 +/- 0.05% in the tumoral region, 1.01 +/- 0.23% in the peritumoral region and 0.35 +/- 0.01 in the para-tumoral region. Using the same markers on fetal liver cells we have also identified small populations of CD117+/CD90+ cells (0.28 +/- 0.07%) and CD117+/CD34+ cells (1.13 +/- 0.24%), presumably resident stem cells or hematopoietic stem cells. Immunomagnetic negative separation was then performed on fetal liver cells using monoclonal antibodies against specific markers of hematopoietic lineages such as CD3, 14, 16, 19, 22, and CD56 to eliminate this population. The remaining cells were then incubated with fluorescently labeled monoclonal antibodies against CD90 and CD117 and analyzed using fluorescence microscopy. As expected these markers were expressed on the majority of the selected cells (89.28 +/- 9.56%). Isolation using appropriate markers and initiation of primary cultures is a first step to the therapeutic use of fetal stem cells and for the study of adult liver stem cells involvement in carcinogenesis.

Susceptibility testing of Streptococcus mitis group isolates.

BACKGROUND & OBJECTIVES: Suppurative oral and maxillofacial infections are usually mixed infections due to aerobic and anaerobic bacteria, most frequently by oral streptococci and antimicrobial treatment is necessary for such infections. The aim of this study was to investigate the antimicrobial susceptibility of Streptococcus mitis group strains isolated from Romanian patients with different oral and maxillofacial infections. METHODS: Eighty-five isolates belonging to S. mitis group isolated from pus samples were identified at species level by the Rapid ID 32 STREP system. The E test was used to determine the susceptibilities of the isolates to penicillin, ampicillin, cefotaxime, erythromycin, clindamycin, chloramphenicol and tetracycline. RESULTS: Of the 151 samples studied, 85 isolates belonged to S. mitis group. The minimum inhibitory concentration (MIC) values (mg/l) ranged from 0.016-0.75 for penicillin, 0.016-2 for ampicillin, 0.016- 1 for cefotaxime, 0.016-4 for erythromycin, 0.016-0.047 for clindamycin, 0.5-4 for chloramphenicol and 0.047-256 for tetracycline. INTERPRETATION & CONCLUSION: The low susceptibility and the resistance to some commonly used antibiotics found in this study indicated a need for a careful surveillance of the susceptibility pattern of oral streptococci isolates of clinical significance. Clindamycin and chloramphenicol might be suitable alternative agents in treatment of oral and maxillofacial infections involving penicillin-resistant bacteria and in case of patients with hypersensitivity to beta-lactam antibiotics.

Activity of telithromycin and seven other agents against 1034 pediatric Streptococcus pneumoniae isolates from ten central and eastern European centers.

OBJECTIVE: To test the activity of telithromycin against 1034 Streptococcus pneumoniae isolates from pediatric patients in ten centers from ten central and eastern European countries during 2000-2001, and to compare it with the activities of erythromycin A, azithromycin, clarithromycin, clindamycin, and quinupristin-dalfopristin. METHODS: The minimum inhibitory concentrations (MICs) of telithromycin, erythromycin A, azithromycin, clarithromycin, clindamycin, levofloxacin, quinupristin-dalfopristin and penicillin G were tested by the agar dilution method with incubation in air, and mechanisms of resistance to macrolides and quinolones were investigated. RESULTS: Strains were isolated from sputum, tracheal aspirates, ear, eye, blood, and cerebrospinal fluid. Among S. pneumoniae strains tested, 36% had raised penicillin G MICs (>/= 0.12 mg/L). Susceptibilities were as follows: telithromycin, quinupristin-dalfopristin and levofloxacin, >/= 99%; clindamycin, 83%; and erythromycin A, azithromycin and clarithromycin, 78%. Of 230 (22.3%) erythromycin A-resistant S. pneumoniae strains, 176 (79.6%) had erm(B), 38 (16.1%) had mef(A), and 10 (4.3%) had mutations in 23S ribosomal RNA or in ribosomal protein L4. The rates of drug-resistant S. pneumoniae are high in all centers except Kaunas, Riga, and Prague. CONCLUSION: Telithromycin had low MICs against all strains, irrespective of macrolide, azalide or clindamycin resistance. Ribosomal methylation was the most prevalent resistance mechanism among all resistant strains, except in Sofia, where the prevalence of the efflux mechanism was higher.

Activity of telithromycin compared with seven other agents against 1039 Streptococcus pyogenes pediatric isolates from ten centers in central and eastern Europe.

In total, 1039 pediatric Streptococcus pyogenes isolates from Bulgaria, Croatia, the Czech Republic, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia and Slovenia were studied. All strains were susceptible to penicillin G, levofloxacin, and quinupristin-dalfopristin, 91-100% to telithromycin, and 82-100% to erythromycin, azithromycin, and clarithromycin, and 90-100% to clindamycin. Macrolide resistance occurred mainly in Slovakia (25%), the Czech Republic (17.3%), and Croatia (15.8%). Overall, 9.7% of S. pyogenes isolates were erythromycin resistant due to erm(B)- or erm(A)-encoded methylases (72.3%) or to a mef(A)-encoded efflux pump (25.7%). One strain had alterations of both 23S rRNA (A2058G Escherichia coli numbering) and ribosomal protein L22 (G95D).

[Hepatic serial resection. Portal vein resection followed by hepatic resection in second time]. / Rezectia hepatica seriata. Ligatura de vena porta urmata de rezectie hepatica în timpul doi.

Hepatic resection still remains the only potential curative treatment for either primary or secondary malignant liver tumors. In order to increase the resectability of initially considered non-resectable tumors and to decrease the posthepatectomy morbidity and mortality, ligature of a portal branch with consecutive hepatic resection is recommended. The ligature of a portal venous branch was performed in 12 patients with gross hepatic tumor: hepatocellular carcinoma (2), peripheral cholangiocarcinoma (5), hepatic metastases from colorectal cancer (5). Two-stage hepatectomy was performed in 5 patients. The interval between the two operations ranged between 4 weeks and 6 months. Hepatic resection could not be performed in 7 cases due to the loco-regional progression of the disease (4 cases) or to the absence of the hypertrophy-atrophy process (3 cases). Hepatic failure occurred posthepatectomy in 2 patients, resulting in the death of one of the patients. Two patients died at 5 and 10 months respectively while two other patients are still alive, free of recurrence at 6 and 12 months respectively. In conclusion, portal vein ligature can be considered in selected cases of unresectable gross hepatic tumors that can be eventually, resected in a second operation. The two-staged hepatectomy is not always feasible. Moreover, the hypertrophy of the controlateral lobe does not always prevent the postoperative hepatic failure..

Flow cytometric determination of Enterococcus spp. susceptibility to four antimicrobial agents.

Two Enterococcus strains (E. faecalis and E. faecium) isolated from 2 patients in an intensive care unit (blood and drain, respectively) were analyzed for susceptibility to 4 antibiotics (penicillin, vancomycin, gentamicin, streptomycin) by agar dilution standard method (MICs), time-kill and flow cytometry. We compared the data from classical methods of antibiotic susceptibility detection, that are compulsory 24 hrs long and flow cytometry results at 5 and 24 hrs cultivation. The results from both classical and flow cytometric analyses were highly cogent and revealed the fact that flow cytometry is very useful in early diagnosis of bacterial resistance to antibiotics.

Study of the sensitivity to antimicrobial drugs of some S. pneumoniae strains isolated from different pathological states.

76 Str.pneumoniae strains isolated from different clinical disease forms were studied for the sensitivity to antimicrobial drugs using the diffusimetric method and the dilution in agar method (MIC to penicillin). The results revealed that 44.74% of pneumococci were sensitive to penicillin, the remaining pneumococci being resistant; 18.42% showed a high resistance (MIC > or = 2 micrograms/ml). A close relationship was seen between sensitivity to penicillin on the one hand and the Pneumococcus origin and serotype on the other. As concerning the multiresistance to antimicrobial drugs, 47.4% of the strains presented resistance to > or = antibiotics belonging to different classes, the most frequent resistance pattern being P, E, Te, SxT. The most active antimicrobial drugs were vancomycin, amoxiclave, rifampicin, followed by ceftriaxone and amoxicillin.

Antibiotic resistance study of invasive S.pneumoniae.

121 invasive pneumococci isolated from meningitis, septicemia, pneumopathies and other clinical infections (osteo-arthritis, peritonitis, sinusitis, otilis, conjunctivitis, plagues) were screened for susceptibility to penicillin G (P), erythromycim (E), chloramphenicol (Cl), tetracycline (T), ceftriaxone (Cro), and sulfametoxazole trimethoprim (SxT) by diffusimetric method, by MICs to P and Cro by agar dilutions and E-test. 48.8% were penicillin resistant (MICs > 0.12 microgram/ml), 22.7% being highly resistant (MICs 3-8 micrograms/ml). Any strain was resistant to P only, but patterns with P included were frequent (55.8%). Resistance to SxT was highest (monoresistance 25.6% as well as polyresistance 69.8%). 72.9% were resistant strains to > or = 1 antibiotic with 12 patterns of resistance (1-5 antibiotics). All of the strains were susceptible to Cro (MICs-0.003-0.5 microgram/ml). Resistance was closely correlated to serotypes 6,9,14,19,23 to site of isolation and diagnosis. Pneumococci from meningitis were 2-3 times more susceptible to P,E,Cl,T and SxT than the isolates from pneumopathies or other infections.

Metastatic tumors to the jaws and oral cavity.

Observations of the incidence of MT from distant organs and tissues to the maxillofacial region are presented on the basis of 13 cases (3.2% of the total number of patients with malignant tumors). Metastatic carcinomas are most frequently found in the mandible (61.5%). The primary locus is usually the breast, kidney, bronchus, or thyroid gland (61.5%), the diagnosis of metastasis aided in localization of the primary tumor. Successful results of radical treatment were obtained in only two cases; they survived for three and 11 years. The other 11 patients died within two months to a year. The function of maxillofacial surgeons in discovering primary and metastatic tumors of the jaws and face is emphasized.