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Biomedical subjects

A Boulos

Publications and source records attributed to A Boulos.

7 recordsLinked to original sources
PubMed2005

Molecular evaluation of antibiotic susceptibility of Tropheryma whipplei in axenic medium.

OBJECTIVES AND METHODS: Whipple's disease is a rare multisystem chronic infection, involving the intestinal tract as well as various other organs. Tropheryma whipplei is a slow-growing facultative intracellular bacterium that remains poorly understood. In vitro antibiotic susceptibility testing has previously been assessed in cells using a real-time quantitative PCR assay. In this study, we have evaluated the antibiotic susceptibility of three strains of T. whipplei grown in axenic medium using the same assay. RESULTS: The active compounds in axenic medium were doxycycline, macrolide compounds, penicillin G, streptomycin, rifampicin, chloramphenicol, thiamphenicol, teicoplanin, vancomycin, amoxicillin, gentamicin, aztreonam, levofloxacin and ceftriaxone, with MICs in the range 0.06-1 mg/L. Cefalothin was less active, with MICs in the range 2-4 mg/L. We found that co-trimoxazole was active with MICs in the range 0.5-1 mg/L, and sulfamethoxazole alone was active with MICs in the range 0.5-1 mg/L. MICs of trimethoprim varied from 64-128 mg/L. CONCLUSIONS: Co-trimoxazole was effective in vitro, but this activity was due to sulfamethoxazole alone. These results were in accordance with the fact that T. whipplei does not contain the encoding gene for dihydrofolate reductase, the target for trimethoprim.

Anti-Bacterial Agents↗
PubMed2003

Molecular evaluation of antibiotic susceptibility: Tropheryma whipplei paradigm.

Tropheryma whipplei, the agent of Whipple's disease, grows fastidiously only in cell cultures without plaque production, and only three strains have been passaged. The formation of bacterial clumps in the supernatant precludes enumeration of viable bacteria and MIC determination. We evaluated the bacteriostatic effects of fluoroquinolones against two T. whipplei isolates by measuring the inhibition of the DNA copy number increase by real-time quantitative PCR. The analysis of the T. whipplei genome database allowed the identification not only of the gyrA gene but also the parC gene encoding the alpha subunit of the natural fluoroquinolone targets DNA gyrase (GyrA) and topoisomerase IV (ParC), respectively. The parC gene was detected in actinobacteria for the first time. High ciprofloxacin MICs (4 and 8 micro g/ml) were correlated with the presence in T. whipplei GyrA and ParC sequences with an alanine residue at positions 83 and 80 (Escherichia coli numbering), respectively. Alanines at these positions have previously been associated with increased fluoroquinolone resistance in E. coli and mycobacteria. However, the MIC of levofloxacin was low (0.25 micro g/ml). The same T. whipplei GyrA and ParC sequences were found in two other cultured strains and in nine uncultured tissue samples from Whipple's disease patients, allowing one to speculate that T. whipplei is naturally relatively resistant to fluoroquinolones.

Actinobacteria↗
PubMed2000

Acute treatment with tamoxifen reduces ischemic damage following middle cerebral artery occlusion.

Inhibitors of cell-swelling-activated anion channels, including the antiestrogenic compound tamoxifen (TAM), have been shown to attenuate the increase in excitatory amino acids (EAA) during ischemia. Since TAM enters the CNS we tested whether it provides protection from damage due to reversible middle cerebral artery occlusion (rMCAo) in rats. TAM (5 mg/kg, i.v.) infused 25 min before ischemia, potently reduced the total volume of the infarct from 328 +/- 34 mm3 to 41 +/- 21 mm3, a reduction of 87%, as measured by TTC staining. It was equally effective when infused starting at 1 h after reperfusion, i.e. 3 h after initiation of rMCAo. Protection of neurons was also found histologically. TAM had no effect on CBF as measured by hydrogen clearance. This appears to be the first report of a marked neuroprotective effect of TAM. Further studies are needed to determine whether its effects are due to inhibition of EAA release and/or other potential neuroprotective sites of action.

Animals↗
PubMed1995

Factors influencing the outcome of in-vitro fertilization with percutaneous aspirated epididymal spermatozoa and intracytoplasmic sperm injection in azoospermic men.

In-vitro fertilization (IVF) by intracytoplasmic sperm injection (ICSI) with spermatozoa retrieved by percutaneous epididymal sperm aspiration (PESA) is a novel, simple and effective treatment for azoospermic men. In all, 38 azoospermic men had an IVF/PESA/ICSI cycle. A total of 42 cycles were performed. The aetiology of azoospermia was classified as failed vasectomy reversal (12 patients/16 cycles), inflammatory obstruction (five patients/five cycles), partial testicular failure (five patients/five cycles) and bilateral congenital absence of vas (16 patients/16 cycles). Adequate sperm preparations for ICSI were obtained from 38 of the 42 treatment cycles (90%). The mean fertilization rate was 32.7%, and fertilization occurred in 35 cycles (92.0%). Embryo transfer was performed in 13 out of 14 cycles (93%) in men with a failed vasectomy reversal, four out of five cycles in men with an inflammatory obstruction (80%), four out of four cycles in men with a partial testicular failure (100%), and 14 out of 15 cycles in men with a bilateral congenital absence of vas (93%). The overall pregnancy rate per two or three embryos transferred was 28.6 and 26.3% per treatment cycle respectively. The sperm parameters of the final pooled sperm aspirate preparations varied widely among the four aetiological groups. These parameters were of no value in predicting the fertilization or pregnancy rates (P > 0.05), and neither was the embryo cleavage rate.

Cytoplasm↗
PubMed1995

Simplified sperm retrieval and intracytoplasmic sperm injection in patients with azoospermia.

OBJECTIVE: To evaluate the rate of recovery of spermatozoa from the epididymis using a percutaneous aspiration technique and to assess the fertilization rate following intracytoplasmic sperm injection (ICSI). PATIENTS AND METHODS: Forty-two patients with azoospermia underwent a total of 46 treatment cycles of in vitro fertilization (IVF) and ICSI. The sperm used for ICSI was retrieved percutaneously by fine-needle aspiration and syringe suction (percutaneous epididymal sperm aspiration, PESA) from the epididymis in 28 patients (mean age 34.9 years), over 32 cycles. Six patients underwent microsurgical sperm aspiration (MESA) and in the remaining eight patients, neither percutaneous aspiration nor MESA yielded suitable sperm and spermatozoa extracted from testicular biopsy were used. RESULTS: A total of 362 oocytes were collected and of those, 286 (79%) were subjected to ICSI. Of the injected oocytes, 49 (17.2%) were damaged, 138 (48.3%) achieved normal fertilization and, of those, 112 (81.2%) cleaved. A total of 67 embryos were transferred and 18 more were suitable for cryopreservation. Of the 25 cycles with embryo transfer, eight resulted in a pregnancy and of these, one miscarried. The pregnancy rate was 25% per cycle and 32% per embryo transfer. The implantation rate was 12%. CONCLUSIONS: This extensive series of PESA/ICSI cycles indicates that PESA can be used successfully to retrieve spermatozoa in patients with azoospermia. The technique is simple, cost-effective and is associated with fewer complications compared to an open microsurgical procedure.

Adult↗