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Biomedical subjects

J C Petit

Publications and source records attributed to J C Petit.

At least 73 records · Page 4Linked to original sources
PubMed1993

Immediate reconstruction of massive cranio-orbito-facial defects with allogeneic and alloplastic matrices in baboons.

40 cranio-orbito-facial osseous defects were created in 20 adult male baboons (Papio ursinus) to test the effectiveness of an allogeneic and an alloplastic matrix implant for the functional and morphological repair of the disassembled craniofacial complex. In each animal, one defect was reconstructed with a craniofacial bone segment harvested from donor adult baboons, and processed so as to obtain autolysed antigen-extracted allogeneic (AAA) bone matrix, preserving the bone morphogenetic protein (BMP) activity essential for bone induction. The contralateral defect was implanted with spherical macrobeads of polymethylmethacrylate (PMMA) coated with poly-2-hydroxyethylmethacrylate (PHEMA), and sintered into a porous molded implant, replicating the structural anatomy of the avulsed osseous segment. Histological analysis was carried out on undecalcified and decalcified bone sections prepared from specimens harvested at 3, 6 and 12 months after surgery. In AAA bone, the morphogenetic response was characterized by vascular invasion and mesenchymal cell aggregation after partial resorption of the implanted matrix. This was followed by bone deposition at the osteotomy interfaces and within the medullary spaces of the implanted AAA bone. Although bone ingrowth did occur in some PMMA/PHEMA specimens, the majority of implants showed fibrous union at the recipient interfaces. The limited bone ingrowth may be related to narrow interconnections between larger porous spaces after chemical synthesis of the two polymeric components. Osteogenesis in AAA bone appeared consistent with osteoconductive invasion from the viable bone at the recipient interfaces. In addition, the finding of a delicate trabecular-like bone, appositional to the central areas of the implanted matrix, suggests bone formation by induction.

Animals↗
PubMed1993

Synergy of cefotaxime and fosfomycin against penicillin-resistant pneumococci.

The killing kinetics of cefotaxime and fosfomycin, alone and in combination, against seven clinical isolates of penicillin-resistant pneumococci were studied. The antibiotics were tested at 1 x, 2 x and 4 x the MIC for each individual isolate. The results showed a synergic interaction of the two antibiotics for three of the seven strains. This strategy may be useful clinically.

Cefotaxime↗
PubMed1993

Comparison of enterotoxin production, cytotoxin production, serogrouping, and antimicrobial susceptibilities of Clostridium difficile strains isolated from AIDS and human immunodeficiency virus-negative patients.

We analyzed and compared Clostridium difficile strains isolated from diarrheic stools of 49 human immunodeficiency virus (HIV)-negative and 50 AIDS patients. Our results suggest that distribution patterns of serogroups are different in these two populations. Serogroup C (which has been previously reported to be very resistant to antimicrobial agents) represents 66.0 and 18.4% of the isolates from AIDS and HIV-negative patients, respectively (P < 0.001); the selection of serogroup C could be explained by multiple antibiotic pressure to which AIDS patients have been subjected.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Comparison of three enzyme immunoassays, a cytotoxicity assay, and toxigenic culture for diagnosis of Clostridium difficile-associated diarrhea.

Enzyme immunoassays (EIAs) based on monoclonal antibodies for the detection of Clostridium difficile toxins have recently been developed for clinical use. The aim of this study was to compare three commercially available EIAs, two for toxin A (Premier C. difficile Toxin A; Meridian, Osi, Elancourt, France; and Vidas C. difficile Toxin A; bioMérieux, Marcy l'Etoile, France) and one for toxins A and B (Cytoclone A + B EIA; Cambridge Biotech Corp., Codiapharm, Evian, France), with a cytotoxicity assay and toxigenic culture for the diagnosis of C. difficile-associated diarrhea (CDAD). The study was performed with 285 fresh stools from 285 patients with suspected CDAD. In case of disagreement, the tests were repeated on a frozen aliquot of the same stool sample, and the patient's chart was reviewed. CDAD diagnosis was established in 55 cases (incidence, 19.3%). The sensitivities and specificities of the methods were, respectively, 92.7 and 100% for the cytotoxicity assay, 96.4 and 99.1% for toxigenic culture, 75.5 and 97.8% for Cytoclone, 65.4 and 99.6% for Premier, and 65.4 and 100% for Vidas. The results were uninterpretable in 3.2% of cases with Cytoclone, 0.3% with Premier, and 2.5% with Vidas. We conclude that the cytotoxicity assay and toxigenic culture remain the best methods for the diagnosis of CDAD even though they lack standardization and require 48 to 96 h to obtain the result. Despite their rapidity and simplicity, EIAs are not sensitive enough to be relied on as the sole laboratory test.

Antibodies, Monoclonal↗
PubMed1993

Human cytomegalovirus (HCMV) late-mRNA detection in peripheral blood of AIDS patients: diagnostic value for HCMV disease compared with those of viral culture and HCMV DNA detection.

A reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect a human cytomegalovirus (HCMV) late mRNA in peripheral blood leukocytes (PBL) of 102 human immunodeficiency virus-infected individuals. The clinical value of this new technique for the diagnosis of acute HCMV disease was evaluated in comparison with viral culture and direct amplification of viral DNA (PCR). The sensitivity of the RT-PCR was slightly lower than that of the two other methods, but its specificity was 94%, compared to 55 and 32% for culture and PCR, respectively. Transcription of this late mRNA is linked to viral replication, and its detection in PBL confirms that these cells can support a complete viral cycle. The relationship between complete replicative cycles and HCMV disease makes RT-PCR a useful clinical tool.

AIDS-Related Opportunistic Infections↗
PubMed1992

A reverse polymerase chain reaction method for detection of human cytomegalovirus late transcripts in cells infected in vitro.

A rapid and simple application of the polymerase chain reaction is described for the detection of human cytomegalovirus (HCMV) mRNAs in cells infected in-vitro. The method was first used to study the transcription of two HCMV genes, and confirm the link between the transcription of one, encoding for the major capsid protein, and viral replication. The oligonucleotides chosen in this region were specific for HCMV genome and sensitivity experiments showed that a single infected cell in 5 x 10(5) can be detected. Detection of this transcript should be suitable for diagnostic purposes, permitting the distinction between latency and active infection.

Base Sequence↗
PubMed1992

Rapid detection of cytomegalovirus DNA in cerebrospinal fluid of AIDS patients with neurologic disorders.

A polymerase chain reaction (PCR)-based method was used to detect cytomegalovirus (CMV) DNA in 82 cerebrospinal fluid (CSF) samples from 67 patients infected by human immunodeficiency virus (HIV). The test was positive for 14 patients, 8 of whom had CMV-related neurologic disease proven by viral culture of CSF or histologic examination. Encephalitis was the most frequent manifestation in patients with positive PCR results, but CMV DNA was also present in some patients with peripheral neuropathy or polyradiculomyelitis. All patients with proven CMV neurologic disease were positive by PCR. In contrast, viral culture was negative for 4 of the 8 patients and pathologic studies were available only for 5. The specificity of the PCR-based assay could not be assessed precisely because of the lack of a reference standard, but the results correlated well with clinical course and results of the other methods. These findings suggest that the PCR-based method may be a useful noninvasive tool for the rapid diagnosis of CMV-related neurologic disease.

AIDS-Related Opportunistic Infections↗
PubMed1992

[Evaluation of the immunoenzyme test (Elisa) in detecting Clostiridium difficile toxin A in fecal samples].

Currently, the method of choice in diagnosis of Clostridium difficile-associated intestinal diseases is the detection of toxin B in fecal specimens. This method is long (72 h) and can be realized in laboratories which have tissue culture facilities. Commercial agglutination test have been evaluated but they lack in specificity. An immunoenzymatic test has been recently commercialized for detection of toxin A. We have compared the results of this assay on 275 fecal specimens from patients suspected of having Clostridium difficile-associated intestinal diseases with the results obtained with the cytotoxicity test and the culture. Of the 275 fecal specimens, 58 were positive in cytotoxicity and 53 in Elisa. The overall sensitivity and specificity of the Elisa compared with cytotoxicity were 89.5% and 99.0% respectively. The immunoenzymatic test detecting Clostridium difficile toxin A is an easy test to perform in 2 h 15; it displays a good correlation with detection of toxin B and can be very useful in daily laboratory diagnosis.

Bacterial Toxins↗
PubMed1992

[Bacteriostatic activity and killing curves of eight antibiotics against seven strains of penicillin G-resistant pneumococci].

Increasing resistance to multiple antimicrobial agents including penicillins is a current problem with Streptococcus pneumoniae. Seven cases of severe infection due to penicillin G-resistant pneumococci were seen in two teaching hospitals in Paris (France) during the first half of 1991; six of the strains were recovered from pulmonary secretions (protected brush specimens) and one from cerebrospinal fluid (CSF). The bacteriostatic activity and killing curves of eight antimicrobials against these seven strains were studied. Antimicrobial agents tested included penicillin G (PEN), amoxicillin (AMX), cefotaxime (CTX), imipenem (IPM), rifampin (RIF), vancomycin (VAN), fosfomycin (FOS), and erythromycin (ERO). MICs were determined using the agar dilution method. Killing curves were obtained using a liquid medium inoculated with 10(5) to 10(6) CFU/ml and subjected to continuous agitation; survivors were counted at baseline and after 1, 3 and 5 hours incubation. MICs of each antimicrobial (mg/l) for the seven strains were in the following ranges: PEN: 0.5-2, AMX: 0.5-2; CTX: 0.125-1; IPM: 0.03-0.25; RIF: 0.12-0.25; VAN: 0.25-1; FOS: 16; ERO: 0.06 greater than 4. Overall, bactericidal activity was greatest with vancomycin, followed by imipenem, then amoxicillin. The cefotaxime-fosfomycin combination proved synergistic and exhibited bactericidal activity (2MIC + 2MIC) for three of the seven strains. This study demonstrated the value of the cefotaxime-fosfomycin combination. Both these antimicrobials seem appropriate for the treatment of meningitis caused by penicillin G-resistant pneumococci provided their dosage is adjusted to achieve adequate drug levels in the cerebrospinal fluid.

Amoxicillin↗
PubMed1991

Polyadenylic-polyuridylic acid plus locoregional and pelvic radiotherapy versus chemotherapy with CMF as adjuvants in operable breast cancer. A 6 1/2 year follow-up analysis of a randomized trial of the French Federation of Cancer Centers (F.F.C.C.).

In this study, patients with operable breast cancer T2 or T3, treated by mastectomy + axillary dissection and with invaded axillary nodes (N+), were randomized to receive either: 1) postoperative locoregional and pelvic radiotherapy (RX) and Poly(A).Poly(U) (AU), 60 mg IV once a week for 6 weeks, or 2) CMF (cyclophosphamide 100 mg/sqm P.O. on days 1-14, methotrexate 40 mg/sqm IV on day 1 and 8, fluorouracil 600 mg/sqm IV on day 1 and 8; monthly cycle, for 6 months. Between March 1982 and December 1985, 517 patients were enrolled, 257 of whom were treated by RX + AU and 260 with CMF. The main clinical, pathological and prognostic characteristics were equally distributed in the two groups. The present analysis was conducted after a mean follow-up of 69 months (S.D. = 13). There was no significant difference in overall survival (OS) between the two groups (test adjusted by center and menopausal status); the five-year OS rate was 74% in the RXAU group and 77% in the CMF group. Relapse-free survival (RFS) was significantly higher (p = 0.05) in the RXAU group compared to the MCF group; the five-year RFS rates were 57% and 46% in the two groups respectively. This short, well-tolerated combined RXAU treatment appears to be as efficient as CMF and might offer an alternative to chemo- or hormonotherapy, in case of contraindications to these treatments.

Adult↗
PubMed1991

Use of the SL-IV and the PGL-Tb1 glycolipid antigens in ELISA for the diagnosis of tuberculosis in AIDS patients.

At a predetermined specificity of 100.0%, the sensitivity of ELISA using the PGL-Tb1 and SL-IV antigens and IgG assays was 35.0% for the diagnosis of tuberculosis in AIDS patients (44.1% when tuberculosis was diagnosed before AIDS, 21.7% when AIDS was diagnosed before tuberculosis). Serial assays in sera collected from 11 AIDS patients before tuberculosis was diagnosed indicated that significant antibody titres were detected 10 months before the onset of clinical tuberculosis. Consequently, it was proposed that serodiagnosis using the glycolipid specific antigens should help in deciding on preventive antituberculosis treatment in these patients.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Bacteremias caused by Selenomonas artemidis and Selenomonas infelix.

We report two different cases of bacteremia caused by two recently described Selenomonas species, Selenomonas artemidis and Selenomonas infelix. Both species are normally found in human buccal flora. S. artemidis bacteremia appeared in a patient (number 1) who presented with an air-fluid pulmonary cavity and clinical conditions consistent with an anaerobic lung abscess. While the patient improved with antibiotic therapy, cultures of respiratory secretions yielded Mycobacterium tuberculosis. This case demonstrated a strong possibility of a coexisting lung abscess due to S. artemidis. S. infelix bacteremia appeared in a cancer patient (number 2) with heart disease during preterminal acute respiratory distress. It was more difficult in this case to assess the clinical impact of the Selenomonas organisms on the patient.

Adenocarcinoma↗
PubMed1990

Multiple myeloma of the periodontium. A case report.

Multiple periodontal lesions were the presenting features leading to a diagnosis of multiple myeloma in a 38-year-old male. Ulceration and bleeding from a rapidly growing retromolar myelomatous mass, multiple foci of alveolar bone destruction and cortical expansion together with multifocal skeletal destruction were the hallmarks of the neoplastic process. Radiotherapy and chemotherapy brought a substantial, but temporary, remission with improvement of the periodontal condition. A sudden exacerbation of the died 22 months after the diagnosis was made.

Adult↗