[Microbiological diagnosis of bacteremia from a catheter: a simple method? Results of a retrospective study]. / Diagnostic microbiologique de bactériémie liée à une chambre implantable: une méthode simple? Résultats d'une étude rétrospective.

Diagnosing catheter-related bloodstream infections is important but not always easy and a failure to make the diagnosis may have serious consequences. A high rate of unnecessary catheter removal is noted. We retrospectively compared the clinical and usual methods of microbiological diagnoses of catheter-related sepsis to the speed of detection of the catheter versus peripheral blood cultures using the Bact-Alert system. We analyzed 50 files of patients with central indwelling devices: 16 single lumen catheters and 34 implanted ports. Twenty-one catheters were classified as infected, and we observed an earlier positivity of catheter versus peripheral blood in all cases, but significant for 19 patients. According to standard diagnosis methods, 29 catheters were estimated non-infected, a more rapid detection of peripheral culture was reported for 17 specimens and, for another eight patients, the time of detection was equal to blood culture drawn from the catheter. In this group, four discrepancies were recorded with a differential time in favor of sepsis related to catheters ranging from 0.5 to 2 hours. Because of its simplicity and low cost, we believed that this method could be the first step of a diagnosis of catheter-related sepsis and could, therefore, avoid unjustified removal, in particular for the implanted ports for which the diagnostic methods are less codified than for catheters. A prospective study is ongoing; the design of the study focuses only on implanted ports.

Ubiquitin-dependent protein processing controls radiation-induced apoptosis through the N-end rule pathway.

The ubiquitination of nuclear proteins activated in human lymphocytes undergoing radiation-induced apoptosis and the subsequent downstream proteasomal protein processing, shown to be involved in apoptotic death control, may be dependent on an amino-terminal sequence identity of ubiquitin target proteins, the "N-end rule" pathway. Here we report that this selective pathway controls radiation-induced apoptosis and that it is involved in the initiation of this type of cell death. Dipeptide competitors of protein ubiquitination/processing dependent solely on the basic amino-terminal residues (type I) efficiently inhibited the radiation-induced apoptotic death phenotype, indicating that only the substrates of ubiquitination with basic NH2-terminal amino acids are involved in apoptotic death control. This selective inhibition was followed by an early, overall but also target-specific inhibition of ubiquitination and by an activation and stabilization of poly(ADP-ribose) polymerase (PARP) that occurs through inhibition of ubiquitination of its cleaved form (85 kDa). Interestingly, caspases-3 and -7 were not activated following irradiation, further suggesting that PARP cleavage may be regulated by an N-end rule pathway in a caspase-independent manner. These results highly suggest involvement of this subset of the ubiquitin system in the apoptotic death control and in the specific regulation of PARP activity.

Five years follow-up after 2-chloro deoxyadenosine treatment in thirty patients with hairy cell leukemia: evaluation of minimal residual disease and CD4+ lymphocytopenia after treatment.

Between March 1992 and August 1993, thirty patients with hairy cell leukemia (HCL) were treated in a single institution with 2-chlorodeoxyadenosine (2-CdA) for one course (N=27) or two courses at six month interval (N=3). Sixteen patients were previously untreated, 14 had been treated with alpha interferon (alpha IFN) (N=5), alpha IFN and splenectomy (N=8) and splenectomy, alpha IFN and Deoxycoformycin (N=1). Overall results in 29 evaluable patients were: 25 CR (86%), 3 PR (10%), one failure. The three PR patients relapsed after 18, 24 months and five years. Two were retreated successfully. Two CR patients relapsed after five years. Careful clinical survey, sequential bone marrow biopsies (BMB) with DBA44 immunostaining for assessment of response and detection of residual disease and serially evaluation of lymphocyte subsets counts were performed. Results of bone marrow biopsies study show 1) a progressive reduction in hairy cell infiltration during the first six months after therapy and not after that indicating that the best moment for the evaluation of response may be the sixth month, 2) the persistence of a very small number of DBA44+ cells (80% of BMB). There was a correlation between the presence of > 5% DBA44 positive cells on 6th month BMB and relapse. 60% had an absolute CD4+ lymphocyte count less than 0.2 10(9)/l at least on one examination after treatment. CD4+ lymphocyte level persisted less than baseline level in 8/18 patients tested after four and/or five years. Lymphopenia was less marked in splenectomized patients: 7/7 splenectomized patients tested have recovered a CD4+ lymphocyte count equal to pretherapy level compared to 3/11 non splenectomized patients (p: 0.004). Three opportunistic infections were observed early (first 6 months) after 2CdA therapy: pneumocystis pneumonia, retinitis due to toxoplasma in the patient who failed and legionella pneumonia in a patient retreated after relapse. Two patients developed a second carcinoma 6 and 12 months after therapy. Five patients died, three from a cause unrelated to HCL, one from HCL and one from infection while in second CR. At five years, overall survival is 83% and progression free survival is 66%. Our study shows 1) long-lasting response in the majority of patients after 2-CdA, 2) a correlation between persistent minimal residual disease detected with DBA44 immunostaining and occurrence of relapse and 3) a profound and persistent CD4+ lymphopenia more marked in non splenectomized patients.

Changes in microrheology of acute promyelocytic leukemia cells during all-trans retinoic acid (ATRA) differentiation therapy: a mechanism for ATRA-induced hyperleukocytosis?

According to French and European experience, hyperleukocytosis occurs during ATRA differentiation therapy in about 70% of de novo and 25% of relapsed APL cases. The most frequently suggested cause for this side-effect is an ATRA-induced proliferation of APL cells. However, no definite explanation for such a proliferative effect has been clearly established. Another mechanism directly related to the differentiation of marrow leukemic cells could be a change in their microrheology, allowing their release from the bone marrow and their transfer toward peripheral blood (PB) and tissues. Using a single cell aspiration assay into a glass restrictive channel, we measured APL cell viscosity values in five de novo APL patients. A deformability index (DI) was defined as the ratio of mean normal neutrophil viscosity x 100/mean APL cell viscosity. Results were the following: (1) at diagnosis, two patients had high marrow DI (96 and 250%) and three patients had low marrow DI (16, 17, and 40%); (2) when PB and marrow APL cells were simultaneously tested, PB APL cells display higher DI than marrow APL-cells; (3) the two patients with high initial marrow DI experienced an ATRA-induced hyperleukocytosis after only 1 day of treatment; (4) in the three patients with low initial marrow DI, the DI was increasing during ATRA therapy and hyperleukocytosis seemed to occur when a large amount of maturing APL cells reached a viscosity value similar to that of mature neutrophils. These results suggest that an asynchronism between rheological and morphological maturation in each APL cell might explain the occurrence of hyperleukocytosis in some patients during ATRA differentiation therapy.

Unexpected high incidence of intracranial subdural haematoma during intensive chemotherapy for acute myeloid leukaemia with a monoblastic component.

We report a high incidence of subacute, chronic and sometimes occult intracranial subdural haematoma (SDH) occurring during intensive chemotherapy for acute myeloid leukaemia (AML) with a monoblastic component. Between March 1990 and January 1993, 86 AML patients from our institution were randomized in the multicentric French AML 90 trial. Eight patients (9%) presented a grade > 2 haemorrhagic event, which was intracranial SDH in five of them. All these five SDH patients had hyperleucocytic AML4 or AML5 and had experienced at least one lumbar puncture (LP) before SDH diagnosis (with intrathecal chemotherapy in four cases). SDH diagnosis was assessed on a brain computed tomography scan which was performed 1-9 d after initial SDH symptoms (mainly mild headaches considered a result of prior LP). All these five patients recovered from this severe event after a specified therapy. SDH does not appear to be an uncommon complication of AML4 and AML5 therapy. Its incidence might be under-reported because of poor symptomatology. Lumbar punctures, known to cause exceptional SDH in nonleukaemic patients, might trigger these haemorrhagic events, eventually in combination with other predisposing factors such a haemostasis disorders or leukaemic CNS infiltration.