Che-1 activates XIAP expression in response to DNA damage.

X-linked inhibitor of apoptosis protein (XIAP) is a member of the inhibitor of apoptosis proteins family that selectively binds and inhibits caspase-3, -7 and -9. As such, XIAP is an extremely potent suppressor of apoptosis and an attractive target for cancer treatment. Che-1 is an antiapoptotic agent involved in the control of gene transcription and cell proliferation. Recently, we showed that the checkpoint kinases ATM/ATR and checkpoint kinase 2 physically and functionally interact with Che-1 and promote its phosphorylation and accumulation in response to DNA damage. These Che-1 modifications induce transcription of p53, and Che-1 depletion strongly sensitizes tumor cells to anticancer drugs. Here we show that Che-1 activates XIAP expression in response to DNA damage. This effect is mediated by Che-1 phosphorylation and requires NF-kappaB. Notably, we found that XIAP expression is necessary for antiapoptotic activity of Che-1 and that in vivo downregulation of Che-1 by small interference RNA strongly enhanced the cytotoxicity of anticancer drugs.

Scleroderma-like disorders.

Fibrosing disorders comprise a wide spectrum of heterogeneous diseases characterized by sclerosis of the dermis, subcutis, and sometimes the underlying soft tissues and bone. The hallmark of this group of diseases is skin thickening as in systemic sclerosis with a different distribution pattern and for this reason they have also been referred to as "scleroderma-like" disorders. These diseases may have a different clinical course ranging from a benign disease with a localized cutaneous involvement, to a widespread, systemic, life-threatening disease. Some of them are associated with autoantibodies and/or autoimmune conditions. An accurate recognition of these scleroderma-like diseases is important for the institution of the most appropriate treatment.

[Recurrent new-onset uveitis in a patient with rheumatoid arthritis during anti-TNFalpha treatment]. / Uveite recidivante di nuova insorgenza in paziente con artrite reumatoide in terapia con anti-TNFalpha

Inflammation involving the uveal tract of the eye, termed uveitis, is frequently associated with various rheumatic disease, including seronegative spondylarthropathies, juvenile rheumatoid arthritis, Crohn's disease and Behçet's disease. Scleritis and keratitis may be associated with rheumatoid arthritis and systemic vasculitides such as Wegener's granulomatosis. Immune-mediated uveitis can have a chronic relapsing course and produce numerous possible complications, many of which can result in permanent vision loss. Treatment typically includes topical or systemic corticosteroids with cycloplegic-mydriatic drugs and/or noncorticosteroid immunosuppressants, but often there is an insufficient clinical effectiveness. Anti-TNFalpha therapy is promising in the treatment of sight threatening uveitis, particularly in patients with Behçet's disease. However, there have been also reports of new-onset uveitis during treatment of joint disease with TNFalpha inhibitors. We describe a case of new-onset uveitis in a patient with rheumatoid arthritis during therapy with etanercept at first and infliximab at last. Although we cannot exclude uveitis as linked to rheumatoid arthritis, it is unlike that the uveitis arises when the joint disease is well controlled. The hypothetical paradoxical effect of anti-TNF is here discussed.

High activity of salvage treatment with biweekly paclitaxel-gemcitabine combination in heavily pretreated breast cancer patients.

The treatment of refractory metastatic breast cancer is primarily palliative, without a significant impact on overall survival. Among the innovative combinations in this unfavourable setting, paclitaxel and gemcitabine showed a possible synergistic action and an encouraging activity in some clinical trials. This phase II study was carried out to evaluate paclitaxel-gemcitabine combination in very heavily pretreated advanced breast cancer on a bi-weekly schedule.Thirty-nine women with advanced breast cancer were treated with paclitaxel 150 mg/m2 as 3 hrs infusion, and gemcitabine 1,500 mg/m2 as 30 mins infusion, both drugs administered on days 1, 15, with cycles repeated every 28 days. All but two patients received granulocyte colony stimulating factor (G-CSF) on days 7 to 9 and 20 to 22 of every cycle. More than two third (71%) of the patients had previously received two or more chemotherapy regimens for advanced disease, including almost all active agents in this disease. Objective responses were observed in 18 out of 34 evaluable patients (53%; 95% CI, 36% to 70%). Disease remained stable in 7 patients (21%). Responses by sites were 67% in soft tissue and in bone, and 48% in visceral disease. Median time to progression and overall survival were 9 and 20 months, respectively. Treatment was well tolerated, with G3-4 neutropenia in 8%, and G 1-2 thrombocytopenia in 13% of the patients; non-hematological toxicities were mild, with G3 hepatotoxicity in 5% of the patients, and G3 peripheral neurotoxicity in 10% of the patients. Biweekly paclitaxel/gemcitabine combination with G-CSF support appears to be very active as salvage therapy in heavily pretreated breast cancer patients, with a very favourable safety profile.

Antitumor effect of c-myc antisense phosphorothioate oligodeoxynucleotides on human melanoma cells in vitro and and in mice.

BACKGROUND: Phosphorothioate oligodeoxynucleotides ([S]ODNs) contain a modified internucleoside phosphate backbone. Antisense [S]ODNs targeted to specific oncogenes have been used with some therapeutic success in animal models human leukemia; however, the potential for antisense [S]ODN treatment of solid tumors has only recently been explored. PURPOSE: We evaluated the effects of antisense [S]ODNs targeted to the c-myc oncogene on the proliferation of human melanoma cells in vitro and on the growth of human melanoma xenografts in CD-1 nude (nu/nu) mice, METHODS: The effects of 15-mer [S]ODNs containing c-myc sense, c-myc antisense, and two different scrambled sequences on the proliferation and viability of cultures of three established human melanoma cell lines (M14, JR8, and PLF2) were determined by measuring cell numbers and use of the trypan blue exclusion test. The induction of apoptosis in these cells following treatment with [S]ODNs was evaluated by fluorescence-activated cell sorter (FACS) analysis. FACS analysis was also used to determine the effects of [S]ODN treatment on the proliferation of primary cultures of a human melanoma explant (NG cells). The expression of c-Myc protein in cultured NG cells after treatment with [S]ODNs was examined by western blot analysis. The antitumor activity and the toxic effects of several [S]ODN treatment regimens were monitored by measuring differences in tumor weight (percent tumor weight inhibition), tumor growth rate (tumor growth inhibition), animal lifespan (percent increase in lifespan), the number of toxic deaths and the median number of long metastases in treated and control mice bearing NG xenografts. c-Myc protein expression in NG tumor cells following [S]ODN treatment was evaluated by FACS analysis, and the extent of apoptosis in these cells was determined by FACS analysis and morphologic examination. RESULTS: Treatment with antisense [S]ODNs, but not the others, inhibited the growth of all tested melanoma cultures in vitro; FACS analysis revealed that growth inhibition was associated with the induction of apoptosis. Antisense [S]ODN treatment also led to reduced celluLar levels of c-Myc protein. In vivo, [S]ODN antitumor activity and toxicity were dose and schedule dependent; however, only antisense [S]ODNs exhibited antitumor activity. Mice bearing NG xenografts treated with antisense [S]ODNs showed a marked inhibition of tumor growth, a reduction in the number of long metastases, and an increase in life span. Reduced levels of c-Myc protein and increased levels of apoptosis were also observed in NG tumor cells following antisense [S]ODN treatment. CONCLUSIONS: treatment of human melanoma cells and solid tumors with antisense [S]ODNs targeted to c-Myc inhibits their growth and is associated with the induction of apoptosis.

[Buschke Scleredema, case report]. / Scleredema di Buschke, contributo casistico.

Buschke Scleredema is a rare connective tissue disorder of unknown aetiology, characterized by thickening of the dermis whose characteristics may mainly to mime systemic sclerosis, eosinophilic fasciitis and cutaneous amyloidosis. Scleredema may be associated with a history of an antecedent febrile illness, diabetes mellitus, or blood dyscrasia. Scleredema can be classified into three clinical groups; each has a different history, course, and prognosis. Each one of these share reduction in chest articular movements and limitation of limbs movements. The skin histology is characterised by thickened dermis and increased spaces between large collagen bundles due to increased deposition of mucopolysaccharide in the dermis. Differential diagnosis can be made considering the typical clinical features and the histologic peculiarity. No therapy has been found effective. The authors describe a case of Buschke Scleredema successfully treated by steroids and colchicine. Clinical evaluation of skin induration and thickness as well as ultrasonography were performed at baseline and after treatment.

c-myc antisense oligodeoxynucleotides enhance the efficacy of cisplatin in melanoma chemotherapy in vitro and in nude mice.

This study was designed to assess the efficacy of a new antimelanoma therapeutic strategy that relies on the use of a c-myc antisense 15-mer phosphorothioate oligodeoxynucleotide ([S]ODN), in combination with cisplatin (cis-diamminedichloroplatinum; DDP), which is currently used in the clinical management of melanoma patients. Proliferation and colony formation of melanoma cells were both inhibited by the DDP/c-myc antisense [S]ODN combination to a greater extent than that observed with either agent alone. Inhibition was most effective when DDP was followed by c-myc antisense [S]ODNs. Cell cycle flow cytometric analysis of cells exposed to the two agents either alone or in combination demonstrated that (a) c-myc antisense [S]ODNs induced an accumulation of cells in S phase and apoptosis in a fraction of the cells, detectable at day 5 after the beginning of treatment; (b) DDP induced a block in G2-M phase detectable at day 1, which was partially recovered, and apoptosis similar in extent to that induced by c-myc antisense [S]ODNs; and (c) DDP and c-myc antisense [S]ODNs together induced arrest in G2-M phase, which was maximum at day 3, i.e., delayed as compared to the block induced by DDP. The combination induced a higher percentage of apoptosis, evident at day 3 from the start of treatment, that correlated with a marked reduction in Bcl-2 expression. Mice bearing human melanoma xenografts and treated sequentially with DDP and c-myc antisense [S]ODNs showed a higher inhibition of tumor growth, reduction in the number of lung metastases, and increase in life span compared with those treated with either agent alone. Together, these data lend support to the development of anticancer therapies involving oncogene-targeted antisense ODNs and conventional antineoplastic drugs.

Transferrin-Targeted Nanoparticles Containing Zoledronic Acid as a Potential Tool to Inhibit Glioblastoma Growth.

The treatment of glioblastoma (GBM) is a challenge for the biomedical research since cures remain elusive. Its current therapy, consisted on surgery, radiotherapy, and concomitant chemotherapy with temozolomide (TMZ), is often uneffective. Here, we proposed the use of zoledronic acid (ZOL) as a potential agent for the treatment of GBM. Our group previously developed self-assembling nanoparticles, also named PLCaPZ NPs, to use ZOL in the treatment of prostate cancer. Here, we updated the previously developed nanoparticles (NPs) by designing transferrin (Tf)-targeted self-assembling NPs, also named Tf-PLCaPZ NPs, to use ZOL in the treatment of brain tumors, e.g., GBM. The efficacy of Tf-PLCaPZ NPs was evaluated in different GBM cell lines and in an animal model of GBM, in comparison with PLCaPZ NPs and free ZOL. Tf-PLCaPZ NPs were characterized by a narrow size distribution and a high incorporation efficiency of ZOL. Moreover, the presence of Tf significantly reduced the hemolytic activity of the formulation. In vitro, in LN229 cells, a significant uptake and cell growth inhibition after treatment with Tf-PLCaPZ NPs was achieved. Moreover, the sequential therapy of TMZ and Tf-PLCaPZ NPs lead to a superior therapeutic activity compared to their single administration. The results obtained in mice xenografted with U373MG, revealed a significant anticancer activity of Tf-PLCaPZ NPs, while the tumors remained unaffected with free TMZ. These promising results introduce a novel type of easy-to-obtain NPs for the delivery of ZOL in the treatment of GBM tumors.

Increase of cisplatin sensitivity by c-myc antisense oligodeoxynucleotides in a human metastatic melanoma inherently resistant to cisplatin.

In this study, we evaluated the role of the c-myc oncogene in response to cisplatin (DDP) treatment using two melanoma lines derived from the primary tumor (LP) and metastatic lymph node (LM) of the same patient. These cell lines, which retain the phenotypic profile of the original tumors, were studied for growth behavior, expression of c-Myc oncoprotein, and HLA-I antigen. The LM line shows a higher tumorigenic ability, an increased expression of c-Myc protein, and a lack of HLA-I antigen, compared with the LP line. In addition, LP tumor was relatively sensitive to DDP administration, whereas LM tumor was resistant to DDP treatment. To verify whether the increased c-Myc expression observed in the LM line might be responsible for DDP resistance, a c-myc antisense phosphorothioate oligodeoxynucleotide ([S]ODN) was used to down-regulate c-Myc expression. The administration of DDP plus c-myc antisense [S]ODNs produced a decrease in c-Myc protein levels of approximately 50%, accompanied by a tumor weight inhibition of 65%, similar to that obtained when the sensitive line was treated with DDP alone (tumor weight inhibition = 70%). Analysis of apoptosis demonstrated that the sensitivity to DDP of the LP line was related to the ability of tumor cells to undergo apoptosis. Conversely, DDP treatment was not able to induce apoptosis in the LM line, whereas apoptosis was evident both after treatment with c-myc antisense [S]ODNs alone and, more extensively, in combination with DDP. Taken together, these results clearly indicate an important role of c-myc oncogene in the resistance of melanoma to DDP and demonstrate that treatment with c-myc antisense [S]ODN sensitizes a human melanoma line to DDP treatment.

N-methylformamide effects on cell proliferation and antigenic pattern in HT-29 colon carcinoma cell line.

The effects of the differentiating agent N-methylformamide (NMF) on cell proliferation and antigenic pattern of HT-29 colon carcinoma cells have been investigated. The cell line was cultured in the presence, or absence, of 1% NMF and tested for the above mentioned characteristics, both in vitro and after injection into nude mice. The percentage of cells in the various cell cycle compartments was estimated by flow cytometry. The presentation on the cell surface of molecules such as tumour associated antigens (TAAs), HLA class I molecules and epidermal growth factor receptor (EGF-R) was analysed by ELISA, flow cytometry and immunohistochemistry. Results demonstrate that NMF impairs HT-29 cell proliferation with a remarkable accumulation in the G0/G1 phases, as well as inducing a modification of the membrane antigenic pattern. The presence of NMF in the culture medium decreases the TAAs and EGF-R whereas HLA antigen maintains the same level of positivity in the two cell lines. These alterations are consistent with a different behaviour in vivo of the tumours originated from NMF treated and untreated cells. Tumours derived from NMF treated cells show a delay in the appearance and low levels of immunodetectable carcinoembryonic antigen (CEA) molecules.

Levels of expression of hRPB11, a core subassembly subunit of human RNA polymerase II, affect doxorubicin sensitivity and cellular differentiation.

We have previously shown that the human RNA polymerase II subunit 11 (hRPB11) is among the proteins specifically downregulated upon Doxorubicin (Dox) treatment of human cancer cell lines, and that Dox resistant clones derived upon drug selection express about 20% of the protein present in the original parental cell line. Given the prominent role that this subunit appears to have in eukaryotic cells, and the fact that its deletion causes lethality in yeast, we wanted to test the effect of the reintroduction of parental cell line levels of this subunit in Dox resistant colon cancer cells (LoVoDX). Stable transfectants of LoVoDX expressing parental (LoVoH) levels of hRPB11 showed a reduced sensitivity to the drug without changing the response of these cells to other chemotherapeutic agents, confirming a specific inverse correlation between cellular Dox sensitivity anti-hRPB11 levels of expression. In addition we show here that the levels of expression of this same RNA polymerase II subunit directly affect cellular differentiation, reducing the rate of cell proliferation, clonogenicity and increasing the expression of E-cadherin, a marker of epithelial cell differentiation. As expected from cells with these characteristics, upon in vivo administration of these clones in nude mice, we detected a significant reduction in the size and time of appearance of the primary tumors and overall metastatic capability. Finally, the role played by hRPB11 in regulating the transcription of specific genes is underlined by transient transfection experiments that show transactivation of the E-cadherin promoter by this protein.

Encapsulation of c-myc antisense oligodeoxynucleotides in lipid particles improves antitumoral efficacy in vivo in a human melanoma line.

Phosphorothioate c-myc antisense oligodeoxynucleotides [S]ODNs (free INX-6295) were encapsulated in a new liposome formulation and the antitumor activity was compared to the unencapsulated antisense in a human melanoma xenograft. The systemic administration of INX-6295 encapsulated in stabilized antisense lipid particles (SALP INX-6295) improved plasma AUC (area under the plasma concentration-time curve) and initial half-life of free INX-6295, resulting in a significant enhancement in tumor accumulation and improvement in tumor distribution of antisense oligodeoxynucleotides. Animals treated with SALP INX-6295 exhibited a prolonged reduction of c-myc expression, reduced tumor growth and increased mice survival. When administered in combination with cisplatin (DDP), SALP INX-6295 produced a complete tumor regression in approximately 30% of treated mice, which persisted for at least 60 days following the first cycle of treatment. Finally, the median survival of mice treated with DDP/SALP INX-6295 increased by 105% compared to 84% for animals treated with the combination DDP/free INX-6295. These data indicate that the biological activity and the therapeutic efficacy of c-myc antisense therapy may be improved when these agents are administered in lipid-based delivery systems.

Temozolomide reduces the metastatic potential of Lewis lung carcinoma (3LL) in mice: role of alpha-6 integrin phosphorylation.

The involvement of protein kinase c (PKC) in the mechanism underlying the antimetastatic properties of triazenes was studied in C57BL/6 mice bearing Lewis lung carcinoma (3LL). In vivo and in vitro treatment with temozolomide, an in-vitro active analogue of dacarbazine, or calphostin c produced a concentration-dependent reduction of spontaneous and artificial metastases. Both agents reduced the ability of 3LL cells to adhere to endothelium. Diethylaminoethyl (DEAE)-sepharose chromatography of cell extracts revealed that incubation of 3LL cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) caused a rapid translocation of protein kinase c activity from cytosol to the membrane fraction. Membrane PKC activity induced by TPA was reduced by 60% after treatment with temozolomide. Coincident with these changes, TPA induced phosphorylation of alpha-6 integrin, whereas temozolomide or calphostin c abolished the appearance of this phosphoprotein. These results suggest that temozolomide reduced metastatic potential by interfering with alpha-6 phosphorylation induced by PKC activation.

Pharmacological purging of syngeneic bone marrow ex vivo: effect of treatment with doxorubicin and lonidamine on normal and leukaemic cells of DBA/2 mice.

The in vivo effect of in vitro treatment with doxorubicin plus lonidamine on normal and leukaemic cells was investigated in a mouse model of syngeneic bone marrow transplantation. Different numbers of L5178Y tumour cells or normal bone marrow cells alone, or mixtures of bone marrow and leukaemic cells were incubated with doxorubicin (0.25, 0.5, 0.75, 1 microgram/ml) and/or lonidamine (50 micrograms/ml) and reinfused in DBA/2 mice. Lonidamine potentiated the cytotoxic effect of doxorubicin dependent on doxorubicin dosage and tumour cell concentration. Survival after injection of 10(4) in vitro-treated tumour cells was 42% for doxorubicin 0.75 micrograms/ml alone versus 100% for the combination with lonidamine and 50% for doxorubicin 1 microgram/ml alone versus 100% combination. Reinfusion of normal bone marrow incubated with doxorubicin alone or in combination with lonidamine in lethally irradiated mice did not occur in 12-14% of mice injected, indicating that the repopulating ability of stem cells was spared. These data suggest the potential usefulness of lonidamine in ex vivo purging of bone marrow before autologous bone marrow transplants in haemopoietic malignancies.

A role for c-myc in DNA damage-induced apoptosis in a human TP53-mutant small-cell lung cancer cell line.

Based on the role of p53 in the control of apoptosis following DNA damage, the status of the TP53 gene has been implicated as a major determinant of tumour responsiveness to cytotoxic therapies. In spite of the high frequency of TP53 mutations, small-cell lung cancer (SCLC) is recognised as one of the most chemoresponsive solid tumours. Since the relevance of the TP53 gene status in the modulation of tumour responsiveness is dependent on the molecular/biological context, in the present study, we have examined the relationship between chemosensitivity and susceptibility to apoptosis of a TP53-mutant human SCLC cell line. The cell line, in spite of TP53 mutation, retained an efficient response to genotoxic stress as documented by cells ability to modulate the p53 protein, arrest in the G1 and G2 phases of the cell cycle and its marked susceptibility to apoptosis following treatment with DNA damaging agents. Exposure to DNA-damaging agents caused an increase of c-Myc, a DNA damage-responsive transcription factor. An analysis of damage-induced apoptosis in the presence of an anti-Fas/CD95 inhibitory antibody indicated that Fas/CD95 was not required for the apoptotic response. The results support an implication of c-myc in sensitising cells to apoptosis, since inhibition of c-Myc expression with an antisense oligodeoxynucleotide (AS-ODN) almost abolished the drug-induced apoptotic response. In conclusion, the present results support a role for c-myc in the induction of apoptosis by genotoxic stress in the absence of a functional p53 and provide new insights into the mechanisms that may influence apoptosis in TP53-mutant cells. Elucidation of this pathway and of the possible cooperation with p53-dependent mechanisms may provide a basis for therapeutic intervention.

Ruboxyl, a new nitroxyl derivative of daunorubicin - acute toxicity and antitumor effect in animals.

Ruboxyl (RBX), a new nitroxyl derivative anthracycline, showed an interesting cytotoxic effect on in vitro established human cell lines and an antitumor activity in tumor-bearing animals. In this study, we further investigated the antitumor effect of this drug compared to Doxorubicin (DX) in four in vivo systems of experimental murine tumors. Our data demonstrate that RBX had little effect on the growth of primary tumor, and on the survival, in mice bearing Lewis lung carcinoma (3LL), while the drug showed a higher effect on the growth of B 16 melanoma. In both the experimental murine systems the activity of RBX was similar to that exerted by DX. As regards the leukemia models, RBX induced a significant increase on survival in mice bearing both L1210 or L5178Y leukemias. However, the effect on survival and the number of long-term survivors (LTS) were lower than that observed following DX treatment.

Different effects of sequential combinations of N-methylformamide with 5-fluorouracil on human colon carcinoma cells growing in nude mice.

The effects of the combination of N-methylformamide (NMF) with 5-fluorouracil (5-FU) on tumor growth and morphological features of human colon carcinoma cells (HT29) implanted in nude mice were assessed. Both agents were administered i.p. at tolerable doses: 5-FU at 19 mg/kg for 5 days and NMF at 200 mg/kg for 12 days. Four main schedules were tested: 5-FU alone, NMF alone, NMF followed by 5-FU and 5-FU followed by NMF. The last sequence was the most effective, as compared with the other treatment regimens. In particular, the 5-FU----NMF combination induced a tumor inhibition of about 75% at the end of the treatments (17th day) versus an inhibition of 23%-43% in the other schedules. Morphological observations, carried out by light and electron microscopy, indicated a possible relationship between the presence of structural changes and tumor growth inhibition. The results of this study renew interest in the use of NMF in sequential combination confirming sequence as a critical factor for the optimal combination of NMF and 5-FU.

Schedule-dependent effectiveness of ADM and multiple cycles of DDP on a murine reticulum sarcoma.

The therapeutic index of adriamycin (ADM) and cisplatin (DDP) combination versus repeated sequences of the more active drug (DDP) was investigated on a murine reticulum cell sarcoma of ovarian origin (M5) implanted i.m. in C57BL/6 mice. The antitumor efficacy of multiple cycles of DDP according to different regimens at a prefixed time (every 7 days) or at tumor regrowth was also evaluated. Our data demonstrate that the ADM-DDP combination did not improve the antitumoral efficacy of DDP as single agent, while repeated cycles of DDP led to a significant increase in the host life span. Differences in therapeutic effect were elicited by the two schedules: the regimen at a prefixed time showed a major effect on local tumor control, although the regimen at tumor regrowth was better tolerated.

Antibiotics for preventing respiratory tract infections in adults receiving intensive care.

BACKGROUND: Pneumonia is an important cause of mortality in intensive care units. The incidence of pneumonia in such patients ranges between 7% and 40%, and the crude mortality from ventilator associated pneumonia may exceed 50%. Although not all deaths in patients with this form of pneumonia are directly attributable to infections, it has been shown to contribute to mortality in intensive care units independently of other factors that are also strongly associated with such deaths. OBJECTIVES: The objective of this review was to assess the effects of antibiotics for preventing respiratory tract infections and overall mortality in adults receiving intensive care. SEARCH STRATEGY: We searched Medline, the Cochrane Acute Respiratory Infections Group trials register, proceedings of scientific meetings and reference lists of articles from January 1984 to December 1999. We also contacted investigators in the field. SELECTION CRITERIA: Randomised trials of antibiotic prophylaxis for respiratory tract infections and deaths among adult intensive care unit patients. DATA COLLECTION AND ANALYSIS: Investigators were contacted for additional information. At least two reviewers independently extracted data and assessed trial quality. MAIN RESULTS: Overall 33 trials involving 5727 people were included. There was variation in the antibiotics used, patient characteristics and risk of respiratory tract infections and mortality in the control groups. In 16 trials (involving 3361 patients) that tested a combination of topical and systemic antibiotic, the average rates of respiratory tract infections and deaths in the control group were 36% and 30% respectively. There was a significant reduction of both respiratory tract infections (odds ratio 0.35, 95% confidence interval 0.29 to 0.41) and total mortality (odds ratio 0.80, 95% confidence interval 0.69 to 0.93) in the treated group. On average 5 patients needed to be treated to prevent one infection and 23 patients to prevent one death. In 17 trials (involving 2366 patients) that tested topical antimicrobials the rates of respiratory tract infections and deaths in the control groups were 28% and 26% respectively. There was a significant reduction of respiratory tract infections (odds ratio 0.56, 95% confidence interval 0.46 to 0.68) but not in total mortality (odds ratio 1.01, 95% confidence interval 0.84 to 1.22) in the treated group. REVIEWER'S CONCLUSIONS: A combination of topical and systemic prophylactic antibiotics can reduce respiratory tract infections and overall mortality in adult patients receiving intensive care. The design of the trials included in this systematic review does not allow to assess whether or not the treatment leads to antimicrobial resistance. Trials with different design are warranted to reliably address this question.

Antibiotics for preventing respiratory tract infections in adults receiving intensive care.

OBJECTIVES: Pneumonia is an important cause of mortality in intensive care units. The objective of this review was to assess the effects of antibiotics for preventing respiratory tract infections and overall mortality in adults receiving intensive care. SEARCH STRATEGY: We searched MEDLINE, proceedings of scientific meetings and reference lists of articles from January 1984 to September 1997. We also contacted investigators in the field. SELECTION CRITERIA: Randomised trials of antibiotic prophylaxis for respiratory tract infections and deaths among adult intensive care unit patients. DATA COLLECTION AND ANALYSIS: Trials were assessed for quality and investigators contacted for additional information. MAIN RESULTS: Overall 33 trials involving 5727 people were included. There was variation in the antibiotics used, patient characteristics and the risk of respiratory tract infections and mortality in the control groups. In 16 trials (involving 3493 patients) of a topical and systemic antibiotic combination, the average rates of respiratory tract infections and deaths in the control group were 33% and 28% respectively. There was a significant reduction of both respiratory tract infections (odds ratio 0.36, 95% confidence interval 0.30 to 0. 43) and total mortality (odds ratio 0.80, 95% confidence interval 0. 68 to 0.93). On average five patients needed to be treated to prevent one infection and 23 treated to prevent one death. In 17 trials (involving 2366 patients) of topical antimicrobials the rates of respiratory tract infections and deaths in the control groups were 30% and 24% respectively. There was a significant reduction of respiratory tract infections (odds ratio 0.57, 95% confidence interval 0.46 to 0.69) but not in total mortality (odds ratio 1.01, 95% confidence interval 0.84 to 1.22). REVIEWER'S CONCLUSIONS: A combination of topical and systemic prophylactic antibiotics can reduce respiratory tract infections and overall mortality in adult patients receiving intensive care. [This abstract has been prepared centrally.]