Efficacy and safety of liposomal cytarabine in children with primary CNS tumours with leptomeningeal involvement

PURPOSE

To assess the efficacy and safety of liposomal cytarabine in the treatment of de novo and relapsed leptomeningeal involvement in children with primary CNS tumours.

METHODS

Data from clinical charts were entered into a database for consecutive unselected patients (n=20) from nine Spanish centres. Diagnosis of leptomeningeal involvement was confirmed by cytology, MRI and/or CT scan. The dose of liposomal cytarabine used varied from 20 to 50 mg, by age.

RESULTS

There were 8 females and 12 males, mean age 7.3 years (range 8 months to 18 years). The tumours were: 10 medulloblastomas, 4 ependymomas, 3 primitive neuroectodermal tumours and 3 other tumours. Fourteen had undergone previous chemotherapy and 12 radiotherapy. Nine received concurrent chemotherapy and 2 concurrent radiotherapy. Median follow-up was 244.5 days (range 12- 869). Patients received a median of 5 doses (range 1-9) of liposomal cytarabine. A neurological response (complete or partial) was seen in 11/19 (58%) and a cytological response in 7/10 (64%). Median time to neurological progression exceeded 180 days (range 12-869). Adverse effects were reported in 11/20 patients, but none was grade IV.

DISCUSSION

Liposomal cytarabine was well tolerated and efficacious in this patient group, but prospective randomised trials are needed.

Modifications in host cell cytoskeleton structure and function mediated by intracellular HIV-1 Tat protein are greatly dependent on the second coding exon

The human immunodeficiency virus type 1 (HIV-1) regulator Tat is essential for viral replication because it achieves complete elongation of viral transcripts. Tat can be released to the extracellular space and taken up by adjacent cells, exerting profound cytoskeleton rearrangements that lead to apoptosis. In contrast, intracellular Tat has been described as protector from apoptosis. Tat gene is composed by two coding exons that yield a protein of 101 amino acids (aa). First exon (1–72aa) is sufficient for viral transcript elongation and second exon (73–101 aa) appears to contribute to non-transcriptional functions. We observed that Jurkat cells stably expressing intracellular Tat101 showed gene expression deregulation 4-fold higher than cells expressing Tat72. Functional experiments were performed to evaluate the effect of this deregulation. First, NF-κB-, NF-AT- and Sp1-dependent transcriptional activities were greatly enhanced in Jurkat-Tat101, whereas Tat72 induced milder but efficient activation. Second, cytoskeleton-related functions as cell morphology, proliferation, chemotaxis, polarization and actin polymerization were deeply altered in Jurkat-Tat101, but not in Jurkat-Tat72. Finally, expression of several cell surface receptors was dramatically impaired by intracellular Tat101 but not by Tat72. Consequently, these modifications were greatly dependent on Tat second exon and they could be related to the anergy observed in HIV-1-infected T cells.

Binding of Ru(NH3)5pz2+ to 4-sulfocalix[4]arene sodium salt. Effects of the host-guest interaction on electron transfer processes

The reactions [Ru(NH3)5pz]2++S2O8(2-) and [Ru(NH3)5pz]2++[Co(C2O4)3]3- have been studied in solutions of 4-sulfocalix[4]arene sodium salt. Results show a binding of the ruthenium complex to the calixarene with a 2:1 stoichiometry; that is, a ruthenium molecule binds to two calixarene molecules. This stoichiometry changes when NaCl is added to the medium. Thus, a mixture of 1:1 and 2:1 adducts is found in the presence of 0.1 mol dm(-3) NaCl and only 1:1 adducts when the salt concentration is increased up to 0.3 mol dm(-3). Results show that the binding of the ruthenium complex to the calixarene is due to electrostatic and nonelectrostatic interactions. Kinetic data are interpreted by using the pseudophase model and taking into account the stoichiometry of the ruthenium binding to calixarene. The presence of a supporting electrolyte in the medium produces ion pair formation which exerts an influence on the kinetic rate constants.

In vitro analysis of synergism and antagonism of different nucleoside/nucleotide analogue combinations on the inhibition of human immunodeficiency virus type 1 replication

In this study we have developed an in vitro system to evaluate the combined effect of two NRTIs on HIV replication and to assess their antagonism or synergy. Synergy or antagonism effect was determined in peripheral blood mononuclear cells (PBMCs) to approach a more physiological model than T-cell lines. PBMCs were infected with a full-length HIV-1 clone carrying the luciferase gene as a reporter. The following combinations were investigated: zidovudine+stavudine (ZDV + d4T), lamivudine + abacavir (3TC + ABC), lamivudine + didanosine (3TC + ddI), lamivudine + stavudine (3TC + d4T), tenofovir + stavudine (TDF + d4T), tenofovir + didanosine (TDF + ddI), tenofovir + abacavir (TDF + ABC), tenofovir + lamivudine (TDF + 3TC), tenofovir + zidovudine (TDF + ZDV), stavudine + didanosine (d4T + ddI), zidovudine + lamivudine (ZDV + 3TC), abacavir + didanosine (ABC + ddI), zidovudine + didanosine (ZDV + ddI), and abacavir + stavudine (ABC + d4T). The effect of combining two drugs was evaluated with a quantitative method based on the median-effect principle of Chou and Talalay. A synergistic effect was observed with combinations containing TDF and ZDV or d4T, d4T and ddI and ZDV plus 3TC. In contrast, combinations including TDF + ddI, 3TC + ddI, ABC + ddI, and ZDV + ddI showed an antagonistic effect on the inhibition of viral replication at all levels of inhibition tested. Lower antagonistic effect was also found in drug combinations that included 3TC + ABC, 3TC + TDF, 3TC + d4T, and TDF + ABC. In conclusion, the method developed allows to measure in vitro the effect of different combinations of two NRTIs on HIV replication. The results suggest that combined therapy including TDF with thymidine analogues may be considered for future therapeutic options in contrast to clearly antagonistic combinations such us TDF plus ddI or 3TC plus ddI, that would explain virological failure in clinical studies when these combinations were used.

Massive exophthalmos after traumatic carotid-cavernous fistula embolization

An 18-year-old man without previous clinical problems developed a left traumatic carotid-cavernous fistula after a traffic accident. An endovascular embolization with coils was performed without success. The drainage was derived to the superior ophthalmic vein solely and clinical worsening occurred. Left eye proptosis, chemosis and intraocular pressure increased. Complete ophthalmoplegia developed and visual acuity decreased due to a central retinal vein obstruction. After a second embolization attempt the fistula was closed successfully but proptosis, chemosis and intraocular pressure remained uncontrolled despite medical treatment. Therefore an orbital decompression surgery was performed. Ophthalmoplegia, proptosis and chemosis improved and intraocular pressure was controlled. Although retinal hemorrhages persist, no neovascularization has developed. Central retinal vein occlusion in young patients seems to have a different etiology than in the elderly. In young patients, local factors are more frequently identified than systemic vascular diseases. Early detection of central retinal vein obstruction may prevent deterioration of visual acuity.

[Apical orbital inflammation in giant cell arteritis]

CASE REPORT

Our purpose is to describe a case of an acute optic neuropathy with apical muscle thickening in a patient already diagnosed with giant cell arteritis. Loss of visual acuity and perimetric concentric constriction responded rapidly to intravenous glucocorticoid therapy. There has been no relapse during continued long-term therapy with cyclophosphamide.

DISCUSSION

Giant cell arteritis is a systemic, idiopathic vasculitis; among its less frequent complications is orbital pseudotumor. Our patient required urgent treatment to avoid visual acuity loss due to compressive neuropathy and perineuritis.

The vascular surgeon facing clinical ethical dilemmas (the VASCUETHICS Study): 'V'-shaped association between compassionate attitudes and professional seniority

OBJECTIVE

To evaluate the association between compassionate attitudes and seniority in vascular surgeons facing clinical ethical dilemmas (CED).

SUBJECTS AND METHODS

(1) DESIGN: Cross-sectional. (2) SUBJECTS: Vascular surgeons (residents included) from the 28 vascular teaching departments of one European country. (3) MEASUREMENTS: Multidisciplinary team-designed, structured and self-administered questionnaire consisting of five clinical ethical dilemmas, of which four had conflict between compassion towards a 'small' or 'very costly' beneficial action vs. a reasonable but more 'pragmatic' allocation of health resources. Participants stated their degree of agreement with eight answers representing the two attitudes on a continuous scale. (4) STATISTICS: Cluster analysis and logistic regression model adjusted by confounding factors.

RESULTS

Two hundred and fifty three vascular surgeons (median age 37 years, 74% male) from the 26 participating teaching vascular departments (public hospitals) completed the questionnaire (88% surgeons/department). Cluster analysis identified two groups of surgeons according to their pattern of answers: Group I (n=63) were mainly compassionate whereas Group II (n=180) were mainly pragmatic. The multivariate analysis disclosed, after adjusting for additional private practice, on call services and career status, a significant V-shaped relationship between the compassionate behaviour and seniority. Surgeons with 8-15 years experience were the least compassionate.

CONCLUSIONS

The youngest and the most senior vascular surgeons were more prone to favour compassionate attitudes when facing clinical ethical dilemmas. Although both compassionate and pragmatic attitudes may be legitimate ethically, physicians not favouring compassion may be at risk of leaving the patient without an advocate within the health care system.

Minimum inhibitory concentrations for 25 selected antimicrobial agents against Dichelobacter nodosus and Fusobacterium strains isolated from footrot in sheep of Portugal and Spain

The agar dilution method was used to determine the inhibitory activity of 25 antimicrobial agents against 69 strains of Dichelobacter nodosus and 108 strains of the genus Fusobacterium, all of which were isolated from 90 clinical cases of ovine footrot between October 1998 and November 2000. In the case of the micro-organisms belonging to the genus Fusobacterium, the six beta-lactams studied (benzyl penicillin, ampicillin, cloxacillin, cefadroxil, cefuroxime and cephalexine) proved to be, in general, the most effective antimicrobial agents. Chloramphenicol, clindamycin and doxycycline were also quite active against Fusobacterium spp. With regard to the 69 strains of D. nodosus tested, the levels of resistance remain low.

Aetiology of ovine footrot in the Portuguese region of Alto Alentejo

In this work, we found it appropriate to carry out a study directed towards isolating and identifying the entailed microorganisms which trigger off footrot in sheep, placing special emphasis on the serotipification of the different Dichelobacter nodosus species. With this goal in mind four flocks from the Portuguese region of 'Alto Alentejo' were selected, all of them had one common feature: their main health problem was ovine footrot. We also set out to determine the elastolitic capacity of isolated strict-anaerobic bacteria, in order to be able to clarify the direct involvement of these microorganisms in the outbreak of this infectious process.

Ribotyping ofFusobacterium necrophorumStrains Isolated from Bovine and Ovine Hepatic Abscesses

A microbiological study was made of 100 strains of Fusobacterium necrophorum isolated from hepatic abscesses in bovine and ovine herds. Differences between the biological activity and ribotypes within the two F. necrophorum subspecies were studied. Conventional methods identified 89 isolates as F. necrophorum subsp. necrophorum and 11 as F. necrophorum subsp. funduliforme. For ribotyping, 50 strains (35 F.n. subsp. necrophorum, 11 F.n. subsp. funduliforme and 4 reference strains) were digested with restriction endonucleases (HindIII, EcoRI and BamHI) and examined after hybridization with digoxigenin-labelled cDNA probe transcribed from a 16 and 23S rRNAs from Escherichia coli. The most discriminating restriction endonuclease enzymes for ribotyping were EcoRI and BamHI. The presence or absence of two distinct band of 5 kb (EcoRI) and 10.5 kb (BamHI) differentiated the two subspecies. This technique also revealed genetic differences between isolates which could be used in the epidemiological study of clinical processes caused by F. necrophorum.

Minimum inhibitory concentrations for selected antimicrobial agents against Fusobacterium necrophorum isolated from hepatic abscesses in cattle and sheep

Minimum inhibitory concentrations for 35 antimicrobial agents against 100 Fusobacterium necrophorum isolates from hepatic abscesses in sheep and cattle were determined. Twelve of the thirteen beta-lactam antibiotics tested inhibited growth of 100% of strains tested. Of the remaining antimicrobial agents, extensive susceptibility was found for: spiramycin, josamycin, lincomycin, tylosin, oxytetracycline, chlortetracycline, rufloxacin, metronidazole, cotrimoxazole, sulfadimethoxine, virginiamycin and fosfomycin.

Comparative in vitro activity of 11 beta-lactam antibiotics against 91 Staphylococcus intermedius strains isolated from staphylococcal dermatitis in dogs

A study was made of the susceptibility of 91 strains of Staphylococcus intermedius, isolated from staphylococcal dermatitis of dogs, to 11 beta-lactam antimicrobial agents. The activity of these antimicrobial agents against all strains was tested at pH 7.2 and 8.5. Finally, a comparative study was made of the susceptibility of these micro-organisms, dividing them into six groups: beta-lactamase positive and negative, methicillin resistant and susceptible and oxacillin resistant and susceptible. Only three of the 11 antimicrobial agents studied exhibited satisfactory behaviour at the two pH levels studied: mezlocillin, cefazolin and cefalotine. There was a good correlation at pH 8.5 between methicillin-resistant strains and those resistant to penicillin G, ampicillin, amoxycillin, cefamandole and cefuroxime. This correlation was not observed, however, between oxacillin-resistant strains and strains resistant to the other antimicrobial agents studied.