Synthesis of the biologically active beta-subunit of human nerve growth factor in Escherichia coli.

The gene (NGFB) encoding the beta subunit of mature human nerve growth factor (hNGFB) was subcloned into the pJLA503 expression vector under the control of bacteriophage promoters PR and PL, and expressed in Escherichia coli. The recombinant protein represented approximately 3% of the total cellular protein. Biologically active hNGFB was solubilized (0.2% total NGFB) and purified by cation-exchange chromatography and it yielded two bands on polyacrylamide-gel electrophoresis under nonreducing conditions, corresponding to the monomeric (14 kDa) and homodimeric (26.5 kDa) forms of the molecule. Both hNGFB forms were immunopositive on Western blots with rabbit anti-NGFB antibodies; however, following additional purification, only the species corresponding to the hNGFB homodimer was biologically active on cultured chicken dorsal root ganglion neurons. These results demonstrate the feasibility of synthesizing the biologically active form of hNGFB in E. coli.

Isepamicin once daily plus ceftriaxone versus amikacin plus ceftriaxone in febrile neutropenic patients.

Isepamicin is a new aminoglycoside with in-vitro activity superior to amikacin. It is a poor substrate for the 6'-aminoacetyltransferase-I enzyme which inactivates amikacin and therefore organisms possessing this enzyme are not resistant to isepamicin. The aim of this study was to compare the efficacy and safety of co-administration of isepamicin once daily plus ceftriaxone to amikacin twice daily plus ceftriaxone to amikacin twice daily plus ceftriaxone in febrile neutropenic cancer patients. Febrile episodes in 235 patients (156 in isepamicin group and 79 in amikacin group) were treated in this study. They occurred in 218 different patients. Fifteen patients were enrolled twice and one three times. Response rates to the two treatment regimens for microbiologically documented episodes, clinically documented episodes and further unexplained fever were similar. Tolerance of the treatment regimens, as measured by serum creatinine levels, hypoaccousia and cutaneous allergy was also similar in both treatment groups. In conclusion, isepamicin given once daily when combined with ceftriaxone in the treatment of febrile episodes in neutropenic cancer patients was as effective and no more toxic than amikacin.

[Role of invasive candidiasis in hospital pathology]. / Place des candidoses invasives en pathologie hospitalière.

The frequency, mode of occurrence, diagnostic criteria and main features of systemic and visceral candidiasis have been evaluated in a retrospective study of all cases managed in St Louis Hospital, Paris, during the [June 1, 1985-May 31, 1986] period. During this one year period 23 patients suffered from systemic or visceral candidiasis and Candida spp. accounted for 9.6% of all positive blood cultures, fourth in number after Enterobacteriaceae, Staphylococcus and Pseudomonas. Abnormal underlying condition was present in all patients, mainly haematologic malignancies, serious abdominal surgery and AIDS. In patients with haematologic malignancies C. tropicalis was the main species involved in contrast with surgical patients in whom the dominant responsible species was C. albicans. No Candida oesophagus was common. Therapeutic regimens included amphotericin B in all patients with systemic disease. We conclude that in an institution mainly oriented toward management of cancer and surgical patients, systemic and visceral candidiasis are common and represent a serious problem.

[High-dose methotrexate and cerebral neurotoxicity. Apropos of a case of arachnoiditis]. / Méthotrexate à fortes doses et neurotoxicité cérébrale. A propos d'une arachnoïdite.

BACKGROUND: High-dose methotrexate has been used as a therapeutic strategy in osteosarcoma for 20 years. Cerebral neurotoxicity is frequent. CASE REPORT: A 21-year-old patient with non-metastatic osteosarcoma was given high-dose methotrexate prior to surgery. He developed subacute encephalitis and arachnoiditis after intravenous injection of methotrexate. COMMENTS: Although pharmacokinetic monitoring and leucovorin rescue is helpful in controlling systemic toxicity, cerebral toxicity with acute, subacute or delayed reactions may occur, depending on the administration route and use of the folate antagonist. Generally, acute arachnoiditis and subacute encephalitis are reversible and occur respectively after intrathecal methotrexate and intravenous high-dose methotrexate, while the chronic delayed leukoencephalopathy usually begins several months after a combination regime using intrathecal methotrexate, intravenous methotrexate and cerebral irradiation.

[Invasive aspergillosis sinusitis in patients infected by the human immunodeficiency virus]. / Sinusites aspergillaires invasives chez les patients infectés par le virus de l'immunodéficience humaine.

Invasive aspergillus sinusitis invasive is a rare, life threatening infection observed in immunocompromised patients. We report three cases of patients with AIDS. Diagnosis was based on surgical biopsy specimen performed on patients with unilateral sinusitis with facial pain and osteolysis on CT scanning, associated in one patient with neurological disorders. One patient with frontal sinusitis and meningeal involvement died despite therapy. One patient with limited maxillary sinusitis who underwent surgical satisfactory resection and antifungal therapy was successfully treated without relapse 12 months later. One patient with orbital and cavernous sinus extension of ethmoiditis was successfully cured with antifungal therapy by itraconazole. Our results confirm the necessity of early diagnosis when clinical and CTscanning are suggestive and the curability of aspergillus sinusitis.

[Portal vein thrombosis associated with an acute cytomegalovirus infection]. / Thrombose portale associée à une infection aiguë à cytomégalovirus.

UNLABELLED: Portal vein thrombosis is an unusual condition and its association with an acute cytomegalovirus (CMV) infection is known but rarely reported. We present here the case of a 24-year-old woman suffering from a symptomatic portal vein thrombosis, confirmed by CT angiography, and acute CMV-related hepatitis. Besides a second generation oral contraceptive with estrogen and progesterone, not associated with smoking, the acute CMV infection was the only cause found to have provoked the venous thrombosis; a myeloproliferative disorder or biological thrombophilia were ruled out. The patient rapidly recovered with vitamin K antagonists (VKA) anticoagulant treatment. Eighteen cases of splanchnic vein thrombosis complicating acute CMV infection were found in the literature. All patients had acute hepatitis. The outcome was usually favorable with warfarin therapy for a period lasting 3 to 7 months. Antiviral treatment (anti-CMV) was used in three cases of severe infection. The antiviral therapy was given only in immunosuppressed patients. For immunocompetent patients, CMV infection is usually asymptomatic and clinical signs are often non-specific and mild, not requiring treatment. CONCLUSION: This case report and the review of the literature recall the need to search for acute CMV infection in patients with portal thrombosis so a possible transient trigger for venous thromboembolism can be identified, avoiding extended anticoagulation.

Role of beta-lactamases in the resistance of gram-negative bacilli to beta-lactam antibiotics.

Few studies in animal models or humans have been performed to prove that the mechanism of resistance to beta-lactam antibiotics in the presence of beta-lactamases is similar in vivo and in vitro. In vivo, it seems likely that different parameters will influence each other: the penetration of the antibiotic into the site of infection; the stability of the drug; and the organism responsible for the infection, which affects the type and amount of beta-lactamase released into the environment. In vitro, the different enzymatic parameters responsible for the inactivation of various compounds have been well defined. However, overall resistance to beta-lactams in the presence of beta-lactamase may also be influenced by the function of the outer membrane in gram-negative bacteria.

Pulmonary localization of Enterocytozoon bieneusi in an AIDS patient: case report and review.

Enterocytozoon bieneusi is an agent of intestinal microsporidiosis leading to malabsorption syndrome and diarrhea in AIDS patients. Respiratory tract microsporidiosis due to Encephalitozoon spp. has been reported. To date, however, only two cases of pulmonary involvement of E. bieneusi have been documented for patients with intestinal microsporidiosis. We report here another pulmonary localization of E. bieneusi in a human immunodeficiency virus-infected patient. Clinical features of these three cases are reviewed. E. bieneusi can colonize the respiratory tract but could be considered a simple carriage associated with an intestinal infection.

Large scale purification and immunological characterization of human placental nerve growth factor.

Nerve growth factor (NGF) is a protein which plays a critical role in the development and survival of not only peripheral neurons, but possibly also cholinergic brain neurons. The present study describes a procedure for large scale isolation of human NGF of placental origin, and its immunological characterization. A protein species of approximately 26 kDa was obtained, which cross-reacted with antibodies to mouse NGF. Polyclonal and monoclonal anti-mouse NGF antibodies appeared to recognize different bands within this human NGF preparation. Although these polyclonal antibodies recognized both the dimeric and monomeric forms of mouse NGF, the monoclonal antibody recognized only a band corresponding to the dimeric form of mouse NGF.

Population pharmacokinetic study of isepamicin with intensive care unit patients.

The pharmacokinetics (PK) of isepamicin, a new aminoglycoside, were studied in 85 intensive care unit (ICU) patients and were compared with those observed in 10 healthy volunteers. A parametric method based on a nonlinear mixed-effect model was used to assess population PK. Isepamicin was given intravenously over 0.5 h at dosages of 15 mg/kg once daily or 7.5 mg/kg twice daily. The data were fitted to a bicompartmental open model. Compared with healthy volunteers, the mean values of the PK parameters were profoundly modified in ICU patients: elimination clearance was reduced by 48%, the volume of distribution in the central compartment (Vc) was increased by 50%, the peripheral volume of distribution was 70% higher, the distribution clearance was 146% lower, and the elimination half-life was ca. 3.4 times higher. The interindividual variability in PK parameters was about 50% in ICU patients. Five covariates (body weight [BW], simplified acute physiology score [SAPS], temperature, serum creatinine level, and creatinine clearance [CLCR]) were tentatively correlated with PK parameters by multivariate linear regression analysis with stepwise addition and deletion. The variability of isepamicin clearance was explained by three covariates (BW, SAPS, and CLCR), that of Vc was explained by BW and SAPS, and that of the elimination half-life was explained by CLCR and SAPS. Simulation of the concentration-versus-time profile for 500 individuals showed that the mean peak (0.75 h) concentration was 18% lower in ICU patients than in healthy volunteers and that the range in ICU patients was very broad (28.4 to 95.4 mg/liter). Therefore, monitoring of the isepamicin concentration is in ICU patients is mandatory.

Isepamicin in intensive care unit patients with nosocomial pneumonia: population pharmacokinetic-pharmacodynamic study.

A population approach was used to determine isepamicin pharmacokinetics in 196 intensive care unit patients treated for nosocomial pneumonia with isepamicin and a broad-spectrum beta-lactam. Patients were randomized in four groups with respect to the following isepamicin dosing regimens: (i) 15 mg/kg od for 5 days or (ii) 10 days, (iii) 25 mg/kg on the first day followed by 15 mg/kg od for 4 days or (iv) 9 days. A total of 1489 serum isepamicin concentrations were measured (median, eight per patient; range, 1-18). Mean +/- S.D. 1 h-peak levels at day 1 were 76 +/- 32 mg/L after the 25 mg/kg dose (n = 85) and 43 +/- 15 mg/L after the 15 mg/kg dose (n = 99). A bicompartmental model was fitted to the data by a mixed-effect modelling approach. Isepamicin clearance was related to age, bodyweight and serum creatinine level. Central volume of distribution was related to bodyweight. Pharmacokinetic parameters were independent of the dosage in the range 15-25 mg/kg and were not different in the patients treated for 5 or 10 days. Bayesian estimates of individual pharmacokinetic parameters were used to calculate various surrogate markers of isepamicin exposure to be tentatively correlated with clinical outcome and nephrotoxicity. No correlation was found between peak, AUC or their ratio with MIC and clinical efficacy. A weak correlation was found between the increase of serum creatinine level (day 1 versus day 5) and isepamicin 24 h trough level at day 1 (R2 = 0.10). These data do not favour a systematic therapeutic monitoring of isepamicin in intensive care unit patients, at least with the doses and antibiotic combinations used in this study.

Fluoroquinolone use and fluoroquinolone resistance: is there an association?

In an assessment of potential risk factors for nosocomial infections caused by fluoroquinolone-resistant gram-negative organisms, 68 patients who developed a nosocomial infection caused by a fluoroquinolone-resistant gram-negative bacillus were compared with 191 patients who developed a nosocomial infection caused by a fluoroquinolone-susceptible gram-negative bacillus. A history of previous infection, immunosuppression, prior receipt of fluoroquinolones, and hospitalization on the burn unit were independent risk factors. Except for immunosuppression, the same risk factors were identified when the 50 patients whose isolates were resistant to fluoroquinolones, aminoglycosides, and beta-lactam antibiotics were compared with the 95 patients whose isolates were susceptible to all of these classes of antimicrobial agents. The identification of hospitalization on the burn unit as a risk factor was attributable to an outbreak of infections caused by a resistant strain of Pseudomonas aeruginosa during the study period. The occurrence of nosocomial outbreaks and the selective pressure of fluoroquinolone use were the main exogenous risk factors involved in the emergence of resistance to fluoroquinolones.

Purification and characterization of Fab fragments from anti-mouse NGF polyclonal antibodies.

A functional role for Nerve Growth Factor (NGF) in the peripheral nervous system is well-documented, but a similar case for NGF in the central nervous system remains to be established. One approach to answering this question would be the availability of high-affinity monospecific Fab fragments obtained against NGF. In the present studies we describe the preparation and characterization of such Fab fragments from anti-mouse NGF polyclonal antibodies. Following their purification by the use of a NGF Sepharose-coupled affinity column, the Fab fragments were examined for biological competence in several ways. In vitro, the anti-Fab fragments blocked the neuronotrophic activity of NGF, as measured by the survival of chicken embryonic day 8 dorsal root ganglion neurons. In vivo, these Fab fragments, when administered systemically to neonatal rats, produced a decrease of noradrenaline levels in two sympathetically innervated organs, the heart and the spleen. These findings suggest that affinity purified Fab fragments of anti-NGF antibodies can be a useful tool for studying the physiological function of NGF in the nervous system.

Recurrent subcutaneous infection due to Scopulariopsis brevicaulis in a liver transplant recipient.

We describe a case of recurrent Scopulariopsis brevicaulis subcutaneous infection, which occurred 6 years after the patient underwent liver transplantation. Combined surgery and long-term oral therapy with terbinafine resulted in a favorable outcome, although this is not the rule in the previously reported S. brevicaulis infections in immunocompromised patients.