Understanding radiation response and cell cycle variation in brain tumour cells using Raman spectroscopy.

Radiation therapy is currently utilised in the treatment of approximately 50% of cancer patients. A move towards patient tailored radiation therapy would help to improve the treatment outcome for patients as the inter-patient and intra-patient heterogeneity of cancer leads to large differences in treatment responses. In radiation therapy, a typical treatment outcome is cell cycle arrest which leads to cell cycle synchronisation. As treatment is typically given over multiple fractions it is important to understand how variation in the cell cycle can affect treatment response. Raman spectroscopy has previously been assessed as a method for monitoring radiation response in cancer cells and has shown promise in detecting the subtle biochemical changes following radiation exposure. This study evaluated Raman spectroscopy as a potential tool for monitoring cellular response to radiation in synchronised versus unsynchronised UVW human glioma cells in vitro. Specifically, it was hypothesised that the UVW cells would demonstrate a greater radiation resistance if the cell cycle phase of the cells was synchronised to the G1/S boundary prior to radiation exposure. Here we evaluated whether Raman spectroscopy, combined with cell cycle analysis and DNA damage and repair analysis (γ-H2AX assay), could discriminate the subtle cellular changes associated with radiation response. Raman spectroscopy combined with principal component analysis (PCA) was able to show the changes in radiation response over 24 hours following radiation exposure. Spectral changes were assigned to variations in protein, specifically changes in protein signals from amides as well as changes in lipid expression. A different response was observed between cells synchronised in the cell cycle and unsynchronised cells. After 24 hours following irradiation, the unsynchronised cells showed greater spectral changes compared to the synchronised cells demonstrating that the cell cycle plays an important role in the radiation resistance or sensitivity of the UVW cells, and that radiation resistance could be induced by controlling the cell cycle. One of the main aims of cancer treatment is to stop the proliferation of cells by controlling or halting progression through the cell cycle, thereby highlighting the importance of controlling the cell cycle when studying the effects of cancer treatments such as radiation therapy. Raman spectroscopy has been shown to be a useful tool for evaluating the changes in radiation response when the cell cycle phase is controlled and therefore highlighting its potential for assessing radiation response and resistance.

Effectiveness of early diagnosis of cerebral palsy guideline implementation: a systematic review.

INTRODUCTION: Tailored implementation interventions are required to overcome the diagnostic research-practice gap for cerebral palsy (CP). Evaluating the impact of interventions on patient outcomes is a priority. This review aimed to summarize the established evidence for the effectiveness of guideline implementations in lowering the age of CP diagnosis. EVIDENCE ACQUISITION: A systematic review was conducted according to PRISMA. CINAHL, Embase, PubMed and MEDLINE were searched (2017-October 2022). Inclusion criteria were studies that evaluated effect of CP guideline interventions on health professional behaviour or patient outcomes. GRADE was used to determine quality. Studies were coded for use of theory (Theory Coding Scheme). Meta-analysis was performed and a standardized metric used to summarize statistics of intervention effect estimates. EVIDENCE SYNTHESIS: Of (N.=249) records screened, (N.=7) studies met inclusion, comprising interventions following infants less than 2 years of age with CP risk factors (N.=6280). Guideline feasibility in clinical practice was established through health professional adherence and patient satisfaction. Efficacy of patient outcome of CP diagnosis by 12 months of age was established in all studies. Weighted averages were: (1) high-risk of CP (N.=2) 4.2 months and (2) CP diagnosis (N.=5) at 11.6 months. Meta-analysis of (N.=2) studies found a large, pooled effect size Z = 3.00 (P=0.003) favoring implementation interventions lowering age of diagnosis by 7.50 months, however study heterogeneity was high. A paucity of theoretical frameworks were identified in this review. CONCLUSIONS: Multifaceted interventions to implement the early diagnosis of CP guideline are effective in improving patient outcomes by lowering the age of CP diagnosis in high-risk infant follow-up clinics. Further targeted health professional interventions including low-risk infant populations are warranted.

Claustrophobia: a proxy for psychological distress in patients with back pain.

STUDY DESIGN: Case-control study. OBJECTIVE: The aim of this study was to assess the levels of psychological distress in patients with back pain who expressed claustrophobia at the time of their magnetic resonance imaging (MRI) scan, compared with sex and age-matched normal controls who did not exhibit claustrophobia. The secondary aim was to document the level of disability and intervention rates in this group. SUMMARY OF BACKGROUND DATA: Psychosocial factors influence the outcomes of low back pain treatment with psychological distress being associated with poorer surgical outcomes in patients with low back pain. Up to 14% of patients experience claustrophobia during MRI scans requiring sedation to complete the scan. The effect of claustrophobia on back pain disability and outcomes has not been previously reported. METHODS: Twenty females and 13 males all requiring MRI scan under sedation for claustrophobia (group 1) were compared with an age and sex-matched cohort that had MRI scan without sedation (group 2). Both groups were drawn from a chronic back clinic. Average age in both groups was 54 years (range, 27 to 79 y). Both groups had standard conservative therapy, together with psychometric evaluation: Zung Depression Index and Modified Somatic Perception Questionnaire. Disability was measured by Oswestry Disability Index. Primary outcome measures were intervention rates (surgery, injections, and physiotherapy sessions) and prevalence of psychological distress. RESULTS: Mean Zung Depression Index in group 1 was significantly higher than in group 2 (59.5 vs. 28.9, P<0.05) as was the mean Modified Somatic Perception Questionnaire score (13.3 vs. 9.2, P<0.05.) Prevalence of psychological distress was higher in group 1 (75.8% vs. 18.2%, P<0.05). Oswestry Disability Index was the same in both groups (50% vs. 48%). Group 1 had 13 interventions (13 patients=39.4%) compared with 26 in group 2 (26 patients=78.8%) (P< 0.05). Twenty-two patients (66.7%) in group 1 were discharged after their MRI scan with no intervention compared with 7 patients (21.2%) in group 2 (P<0.05). CONCLUSIONS: Claustrophobic patients with back pain showed higher levels of depression than nonclaustrophobic patients, with a higher rate of psychological distress. Disability, however, was not higher. The majority of claustrophobic patients did not require surgical intervention. The reasons for this are unclear and require further investigation. Claustrophobia requiring sedation for MRI scans may be a proxy for psychological distress in these patients and psychometric testing is advised during assessment to help with surgical decision making.

Survival and Prognostic Factors in C9orf72 Repeat Expansion Carriers: A Systematic Review and Meta-analysis.

Importance: The c9orf72 repeat expansion (c9 or c9orf72RE) confers a survival disadvantage in amyotrophic lateral sclerosis (ALS); its effect on prognosis in frontotemporal dementia (FTD) remains uncertain. Data on prognostic factors in c9orf72RE disorders could inform patient care, genetic counseling, and trial design. Objective: To examine prognostic factors in c9ALS, c9FTD, c9ALS-FTD, and atypical phenotypes. Data Sources: The MEDLINE, Embase, Amed, ProQuest, PsychINFO, CINAHL, and LILACS databases were searched between January 2011 and January 2019. Keywords used were c9orf72 and chromosome 9 open reading frame 72. Reference lists, citations of eligible studies, and review articles were also searched by hand. Study Selection: Studies reporting disease duration for patients with a confirmed c9orf72RE and a neurological and/or psychiatric disorder were included. A second author independently reviewed studies classified as irrelevant by the first author. Analysis began in January 2019. Data Extraction and Synthesis: Data were extracted by 1 author; a further author independently extracted 10% of data. Data were synthesized in univariate and multivariable Cox regression and are displayed as hazard ratios (HR) and 95% confidence intervals. Main Outcomes and Measures: Survival after symptom onset. Results: Overall, 206 studies reporting on 1060 patients were included from 2878 publications identified (c9ALS: n = 455; c9FTD: n = 296; c9ALS-FTD: n = 198; atypical phenotypes: n = 111); 197 duplicate cases were excluded. The median (95% CI) survival (in years) differed significantly between patients with c9ALS (2.8 [2.67-3.00]), c9FTD (9.0 [8.09-9.91]), and c9ALS-FTD (3.0 [2.73-3.27]); survival in atypical phenotypes varied substantially. Older age at onset was associated with shorter survival in c9ALS (HR, 1.03; 95% CI, 1.02-1.04; P < .001), c9FTD (HR, 1.04; 95% CI, 1.02-1.06; P < .001), and c9ALS-FTD (HR, 1.02; 95% CI, 1.004-1.04; P = .016). Bulbar onset was associated with shorter survival in c9ALS (HR, 1.64; 95% CI, 1.27-2.08; P < .001). Age at onset and bulbar onset ALS remained significant in multivariable regression including variables indicating potential diagnostic ascertainment bias, selection bias, and reporting bias. Family history, sex, study continent, FTD subtype, or the presence of additional pathogenic sequence variants were not significantly associated with survival. Clinical phenotypes in patients with neuropathologically confirmed frontotemporal lobar degeneration-TDP-43, motor neuron disease-TDP-43 and frontotemporal lobar degeneration-motor neuron disease-TDP-43 were heterogenous and impacted on survival. Conclusions and Relevance: Several factors associated with survival in c9orf72RE disorders were identified. The inherent limitations of our methodological approach must be considered; nonetheless, the reported prognostic factors were not significantly associated with the bias indicators examined.

Towards a fair and transparent research participant compensation and reimbursement framework in Vietnam.

BACKGROUND: Providing compensation for participants in clinical research is well established and while international guidelines exist, defining a context-specific and fair compensation for participants in low-resource settings is challenging due to ethical concerns and the lack of practical, national compensation and reimbursement frameworks. METHODS: We reviewed Oxford University Clinical Research Unit (OUCRU) internal reimbursement documentation over a 10-y period and conducted a scoping literature review to expand our knowledge of compensation and reimbursement practices including ethical concerns. We developed a preliminary reimbursement framework that was presented to community advisory boards (CAB) and clinical investigators to assess its applicability, fairness and transparency. RESULTS: The main topics discussed at the workshops centered on fairness and whether the reimbursements could be perceived as financial incentives. Other decisive factors in the decision-making process were altruism and the loss of caregivers' earnings. Investigators raised the issue of additional burdens, whereas the CAB members were focused on non-monetary elements such as the healthcare quality the patients would receive. All elements discussed were reviewed and, where possible, incorporated into the final framework. CONCLUSION: Our new reimbursement framework provides a consistent, fair and transparent decision-making process and will be implemented across all future OUCRU clinical research in Vietnam.

Altered immune parameters associated with Koala Retrovirus (KoRV) and Chlamydial infection in free ranging Victorian koalas (Phascolarctos cinereus).

Koala Retrovirus (KoRV) has been widely speculated to cause immune suppression in koalas (Phascolarctos cinereus) and to underlie the koala's susceptibility to infectious disease, however evidence for immunomodulation is limited. The aim of this study is to determine whether immunophenotypic changes are associated with KoRV infection in free ranging Victorian koalas. qPCR was used to examine mRNA expression for Th1 (IFNγ), Th2-promoting (IL6, IL10) and Th17 (IL17A) cytokines, along with CD4 and CD8 in whole blood of koalas (n = 74) from Mt Eccles and Raymond Island in Victoria, Australia, with and without natural chlamydial infection. KoRV positive koalas had significantly lower levels of IL17A (p`0.023) and IFNγ (p = 0.044) gene expression along with a decreased CD4:CD8 gene expression ratio (p = 0.025) compared to negative koalas. No effect of chlamydial infection or combined effect of KoRV and chlamydial infection was detected in these populations. The decreased expression of IFNγ could make KoRV infected koalas more susceptible to persistent chlamydial infection, and a decrease in IL17A could make them more susceptible to gram negative bacterial, fungal and mycobacterial infection; but more tolerant of chlamydial infection.

External quality control of Mycobacterium tuberculosis drug susceptibility testing: results of two rounds in endemic countries.

SETTING: Quality assurance for the World Health Organization (WHO)/International Union Against Tuberculosis and Lung Disease (The Union) global tuberculosis (TB) drug resistance surveillance programme. OBJECTIVE: To monitor the quality of drug susceptibility testing (DST) in different countries. METHODS: In 2002-2003 and 2005-2006, 20 Mycobacterium tuberculosis strains were sent by the WHO/Union Supranational Reference Laboratory of Rome to TB reference laboratories in Albania, Bahrain, Kosovo, Mozambique, Oman, Qatar and Turkey for external quality control (EQC). RESULTS: In 2002-2003, the specificity, sensitivity, efficiency, reproducibility and predictive values for resistance/susceptibility were >or=90% for streptomycin (SM), isoniazid (INH) and ethambutol (EMB). In 2005-2006, all statistical values were >or=96% for SM, INH, rifampicin and EMB. CONCLUSION: EQC improved the quality of M. tuberculosis DST in the participating countries.

Simple interventions improve re-attendance when treating the sleep apnoea syndrome.

BACKGROUND AND PURPOSE: Interventions to improve treatment outcomes in sleep apnoea-hypopnoea syndrome (SAHS) have had mixed success. Most have concentrated on following the use of a continuous positive airway pressure (CPAP) machines; poorer users may not return for machine readings, so any compliance study must take into account rates of attendance rates. We hypothesised that a series of additional, early support measures would improve re-attendance over a sustained period. PATIENTS AND METHODS: Prospective, single-blinded interventional study. Seventy-two consecutive patients starting CPAP for SAHS were randomised to receive standard follow-up or extra early support. Attendance rates, CPAP use, Epworth scores, side-effects scores and number of changes to equipment were compared, by intent to treat, in both groups at 1 and 12 months. RESULTS: Re-attendance rates were higher in the intervention group at 1 month (P=0.04), 6 months (P=0.07) and 12 months (P=0.12). Those who defaulted tended previously to be poor users of the CPAP machine. For those who re-attended there was no difference in machine use or other outcomes. CONCLUSIONS: Simple interventions while commencing CPAP improve re-attendance with maximal benefit early on. This could provide more opportunities for solving problems early or considering alternative treatments. By confirming that poorer CPAP users eventually have higher default rates we recommend that future studies on CPAP compliance should first account for re-attendance rates.

Altered Immune Cytokine Expression Associated with KoRV B Infection and Season in Captive Koalas.

Koala (Phascolarctos cinereus) populations are increasingly vulnerable and one of the main threats is chlamydial infection. Koala retrovirus (KoRV) has been proposed as an underlying cause of the koala's susceptibility to infection with Chlamydia and high rates of lymphoid neoplasia; however, the regionally ubiquitous, endogenous nature of this virus suggests that KoRV A infection is not sufficient for immune suppression to occur. A recently discovered exogenous variant of KoRV, KoRV B, has several structural elements that cause increased pathogenicity in related retroviruses and was associated with lymphoid neoplasia in one study. The present study assesses whether KoRV B infection is associated with alterations in immune function. Cytokine gene expression by mitogen stimulated lymphocytes of KoRV B positive (n = 5-6) and negative (n = 6-7) captive koalas was evaluated by qPCR four times (April 2014-February 2015) to control for seasonal variation. Key immune genes in the Th1 pathway (IFNγ, TNFα), Th2 pathway (IL 10, IL4, IL6) and Th17 pathway (IL17A), along with CD4:CD8 ratio, were assessed. KoRV B positive koalas showed significantly increased up-regulation of IL17A and IL10 in three out of four sampling periods and IFNγ, IL6, IL4 and TNFα in two out of four. IL17A is an immune marker for chlamydial pathogenesis in the koala; increased expression of IL17A in KoRV B positive koalas, and concurrent immune dysregulation, may explain the differences in susceptibility to chlamydial infection and severity of disease seen between individuals and populations. There was also marked seasonal variation in up-regulation for most of the cytokines and the CD4:CD8 ratio. The up-regulation in both Th1 and Th2 cytokines mirrors changes associated with immune dysregulation in humans and felids as a result of retroviral infections. This is the first report of altered immune expression in koalas infected by an exogenous variant of KoRV and also the first report of seasonal variation in cytokine up-regulation and CD4:CD8 ratio in marsupials.

Does one size fit all? Drug resistance and standard treatments: results of six tuberculosis programmes in former Soviet countries.

SETTING: After the collapse of the Soviet Union, countries in the region faced a dramatic increase in tuberculosis cases and the emergence of drug resistance. OBJECTIVE: To discuss the relevance of the DOTS strategy in settings with a high prevalence of drug resistance. DESIGN: Retrospective analysis of one-year treatment outcomes of short-course chemotherapy (SCC) and results of drug susceptibility testing (DST) surveys of six programmes located in the former Soviet Union: Kemerovo prison, Russia; Abkhasia, Georgia; Nagorno-Karabagh, Azerbaijan; Karakalpakstan, Uzbekistan; Dashoguz Velayat, Turkmenistan; and South Kazakhstan Oblast, Kazakhstan. Results are reported for new and previously treated smear-positive patients. RESULTS: Treatment outcomes of 3090 patients and DST results of 1383 patients were collected. Treatment success rates ranged between 87% and 61%, in Nagorno-Karabagh and Kemerovo, respectively, and failure rates between 7% and 23%. Any drug resistance ranged between 66% and 31% in the same programmes. MDR rates ranged between 28% in Karakalpakstan and Kemerovo prison and 4% in Nagorno-Karabagh. CONCLUSION: These results show the limits of SCC in settings with a high prevalence of drug resistance. They demonstrate that adapting treatment according to resistance patterns, access to reliable culture, DST and good quality second-line drugs are necessary.

Early predictors of CPAP use for the treatment of obstructive sleep apnea.

STUDY OBJECTIVES: To identify factors before a trial of nasal continuous positive airway pressure (CPAP) treatment that are associated with lower compliance. DESIGN: A prospective cohort study. Initial Hospital Anxiety and Depression Scale scores and other demographic data were noted. Machine use was recorded by clock timer after a 1-month trial of treatment. SETTING: District General Hospital sleep-disordered breathing clinic. PATIENTS OR PARTICIPANTS: Eighty consecutive patients with symptoms of sleep apnea-hypopnea syndrome and a 4% Sao2 desaturation index greater than 10 events per hour. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Those reporting 'initial problems' with CPAP went on to have an average of 2.4 hours of on time per night, while those not reporting initial problems had an on time of 5.0 hours per night (P < .001). Those living alone had a machine on time of 3.2 hours compared with 4.5 hours for those with partners (P = .04). Pearson's correlations between hours on time were -0.08 (P = .48) for initial Anxiety score and 0.10 (P = .37) for initial Depression score. CONCLUSIONS: There was no association between baseline anxiety and depression scores, as measured by the Hospital Anxiety and Depression Scale, and subsequent machine use. Other factors observable prior to commencing treatment, in particular, 'initial problems' (reported at autotitration), 'recent life-events' and 'living alone' were associated with lower machine use. Regarding all initial variables, reporting problems after the first night of nCPAP seems the most important predictor of ensuing machine use. A single screening question immediately after autotitration is useful in identifying those at high risk of treatment failure.

Activities of eighteen antimicrobial regimens against Mycobacterium avium infection in beige mice.

The therapeutic effect of 18 anti-Mycobacterium avium regimens was examined in beige mice after 91 days of infection. Treatments included monotherapy with clarithromycin (CLA), ethambutol (EMB), amikacin (AMI), rifabutin (RFB), ciprofloxacin (CIP), clofazimine (CLO), and combinations of CLA, CLA-EMB, or CLA-AMI with one of the other drugs. After monotherapy, only AMI and CLA displayed bacteriostatic and/or moderate bactericidal effects in spleens and lungs, while CIP and RFB were totally inactive and CLO and EMB showed intermediate effects against the isolate tested. Resistant mutants were isolated in spleens of mice treated with EMB, CIP, RFB, and CLO-Among two-drug combinations, CLA-RFB, CLA-CIP, and CLA-CLO were significantly more active than RFB, CIP, CLO, respectively, but not more active than CLA alone, in both organs; CLA-AMI and CLA-EMB were bactericidal in spleens and lungs, respectively. Although activity of CLA-EMB was significantly potentiated by RFB and CLO in spleens and lungs, that of CLA-AMI was significantly increased by RFB and CLO only in lungs. The most active regimen in spleens and lungs on day 91 was the combination of all three, namely CLA-AMI-EMB, which reduced the CFU numbers of 2.7 and 7.5 log10, in comparison with day 1 and day 91 counts in untreated control mice, respectively.

Activity of 16 antimicrobial agents against drug-resistant strains of Mycobacterium tuberculosis.

The in vitro activity of 16 antimicrobial agents against 46 drug-resistant strains of Mycobacterium tuberculosis recently isolated from Italian patients was determined. As for first-line antituberculosis drugs, while isoniazid was ineffective against all the strains tested, resistance to streptomycin, rifampicin, pyrazinamide, and ethambutol was 80.4%, 71.7%, 39.1%, and 8.7%, respectively. Among second-line antituberculous drugs, resistance to ciprofloxacin, ofloxacin, and sparfloxacin and to amikacin and kanamycin was around 20%. About 10% of the strains were resistant to capreomycin and cycloserine and 4.3% were resistant to ethionamide; no strain was found to be resistant to thiacetazone, para-aminosalicylic acid, and viomycin. Although all strains displayed a rather continuous distribution of minimal inhibitory concentrations (MICs), a bimodal distribution was observed for rifampicin, amikacin, and kanamicin, with very high MIC values for resistant strains; relatively low MICs were found for fluoroquinolone-resistant strains. Among the small number of strains resistant to second-line agents, low resistant levels were observed. Restriction fragment length polymorphism analysis showed few strain clusters with resistance to first-line antituberculous drugs and aminoglycosides, fluoroquinolones, or both. Altogether, these results showed that second-line agents were still active against the isoniazid-resistant and multiply first-line resistant strains tested, with none or low resistance levels; these observations can be of importance for the treatment of multidrug-resistant tuberculosis in Italy.

Prevalence of resistance to anti-tuberculosis drugs: results of the 1998/99 national survey in Italy.

OBJECTIVE: To determine the prevalence of resistance to the main anti-tuberculosis drugs in newly and previously treated tuberculosis patients in Italy and to evaluate the contribution of foreign-born and human immunodeficiency virus (HIV) positive cases to drug resistance. METHODS: Methods and definitions were derived from the WHO/IUATLD Global Project on Anti-tuberculosis Drug Resistance Surveillance. Univariate and multivariate analysis was used to study prevalence rates of drug resistance in risk groups. RESULTS: In a national survey in Italy, 810 initial isolates of Mycobacterium tuberculosis (683 from new cases, 115 from retreatment cases and 12 from patients whose treatment history was unknown/dubious) were analysed. Low prevalence of drug and multidrug resistance was found in the new cases (isoniazid 2.9%; rifampicin 0.8%; multidrug resistance 1.2%; any drug resistance 12.3%). The prevalence of resistance to isoniazid and rifampicin was significantly higher in immigrants and HIV-positive subjects, respectively. A high prevalence of drug resistance was found in cases with previous treatment failure or default (isoniazid 5.2%; rifampicin 4.3%; multidrug resistance 36.5%; any drug resistance 61.7%). RECOMMENDATIONS: Special efforts are necessary to monitor trends in drug resistance and to ensure favourable treatment outcomes among immigrants and HIV-positive tuberculosis cases.

In vitro activity of zidovudine alone and in combination with ciprofloxacin against Salmonella and Escherichia coli.

The in vitro antibacterial activity of zidovudine alone and in combination with ciprofloxacin was investigated. Zidovudine showed a good activity against Escherichia coli and Salmonella (MIC range 0.5-8 micrograms/ml and 1.5-62 micrograms/ml respectively) isolated from biological samples of HIV-infected patients. These strains proved to be extremely susceptible to ciprofloxacin alone. The interaction between zidovudine and ciprofloxacin ranged from additive activity to indifference. No antagonism was observed: the FIC index for every combination resulted < or = 1.5. The addition of AZT 1 mg/l (clinically achievable plasma concentration after therapeutic doses of 1200 mg/day) did not affect the bactericidal activity of ciprofloxacin; on the contrary, in some cases we observed an increase of bactericidal effect of the quinolone. These data have to be considered in patients with AIDS who can be treated concomitantly with zidovudine and ciprofloxacin.

Mode of cell death induced in Chinese hamster cells by sequence-selective DNA minor groove binding nitrogen mustards: comparison with untargeted mustards and with Hoechst 33342.

The clinical antitumor efficacy of nitrogen mustards such as chlorambucil may relate to their ability to cause programmed cell death (apoptosis), probably through their DNA cross-linking properties. In contrast, bisbenzimidazoles such as Hoechst 33342 interact noncovalently with the minor groove of DNA, and appear to cause apoptosis in a fundamentally different way, which may involve the inhibition of topoisomerase (topo) I enzymes. A series of DNA minor groove binding nitrogen mustards with selective DNA affinity and in vivo antitumor activity in animal models was studied. Although two examples of such compounds proved to inhibit topo I enzymes in vitro, they were equally toxic towards topo I-proficient and- deficient strains of yeast, suggesting that topo I inhibition was not involved in cell killing. Flow cytometric analysis of Chinese hamster cells highlighted the differences in the propensity to cause apoptosis by chlorambucil compared with Hoechst 33342, revealing two distinct apoptotic populations in cells treated with the latter drug. Unexpectedly, the bisbenzimidazole mustards showed a novel peak of apoptotic activity, distinct from that shown by either parent drug. Exploring these different mechanisms of apoptosis may provide new directions for the development of antitumor drugs.

Activity of antimicrobial drugs evaluated by agar dilution and radiometric methods against strains of Nocardia asteroides isolated in Italy from immunocompromised patients.

Benzylpenicillin, amoxicillin, amoxicillin plus clavulanic acid, cephalothin, cephaloridine, cefotaxime, imipenem, erythromycin, clarithromycin, azithromycin, amikacin, ciprofloxacin and trimethoprim-sulfamethoxazole were tested in vitro by the agar dilution method against eleven strains of Nocardia asteroides isolated both from AIDS and other immunocompromised patients. Imipenem, amikacin and trimethoprim-sulfamethoxazole were shown to be the most active drugs with minimum inhibitory concentrations (MIC) values nearly always lower than concentrations achievable in blood. Ciprofloxacin, cephaloridine and cefotaxime were moderately active, while the remaining drugs were totally ineffective. When susceptibility was assessed by the radiometric method the MIC90 values were uniformly lower than those in the agar method, possibly due to lower inactivation of drugs during incubation. The two methods showed a good correlation only for imipenem, amikacin and ciprofloxacin. The results obtained by the radiometric method seem to indicate that, as for mycobacteria, this method may also give a more accurate evaluation of the antimicrobial susceptibility of Nocardiae.

Type frequency and antimicrobial susceptibility of Mycobacterium avium-intracellulare complex strains isolated in Italy from AIDS and non-AIDS patients.

Typing of the glycopeptidolipid antigens performed by thin layer chromatography on 59 Mycobacterium avium-intracellulare (MAC) strains isolated in Italy from AIDS patients showed that the most frequent types were 1, 4, 3, 8, and 21 (24, 19, 14, 14 and 8% of the strains, respectively). Among non-AIDS patients, types 1, 4 and 8 were also frequently found. The antimicrobial susceptibility tested in agar and/or liquid media to a panel of drugs indicated in clofazimine and rifabutin effective agents against both AIDS and non-AIDS strains. The data obtained show that MAC type distribution in Italy appears to be different from that reported for other countries. No major differences in drug susceptibility between AIDS and non-AIDS related strains were found.

In vitro activity of clarithromycin alone or in combination with other antimicrobial agents against Mycobacterium avium-intracellulare. Complex strains isolated from AIDS patients.

The activity of clarithromycin and five other antimicrobial agents, namely amikacin, rifampicin, rifabutin, clofazimine and ciprofloxacin, was assessed both by an agar dilution and a radiometric method in broth on 11 Mycobacterium avium-intracellulare complex (MAC) strains, recently isolated from AIDS patients. Minimum inhibitory concentrations (MICs) radiometrically determined were, in general, several times lower than MICs assessed in agar, probably because of a partial degradation of antimicrobials during the long incubation period needed for tests in solid medium. When tested in broth, rifabutin and clofazimine showed very low MICs 90 (0.24 and 0.78 microgram/ml, respectively). Ciprofloxacin and clarithromycin also had MICs90 in the range of peak serum levels (1.93 and 3.76 micrograms/ml, respectively). Moreover, all these antimicrobials are known to concentrate several times in macrophages. MICs90 were higher for amikacin (11 micrograms/ml) and for rifampicin (8 micrograms/ml). When clarithromycin was tested against three MAC strains in combination with another drug, it showed a synergistic effect only when combined with rifampicin. Some synergistic effect was observed also when combining clarithromycin with rifampicin and amikacin, whereas in combination with rifabutin and clofazimine there was only an additive effect.

Bacillus Calmette-Guerin down-regulates CD1b induction by granulocyte-macrophage colony stimulating factor in human peripheral blood monocytes.

Non-peptide antigens (e.g. glycolipids of microbial origin) presented by monocyte-associated CD1 molecules to T cells appear to play an important role in host immunity against tuberculosis and other pathogenic bacteria. Since vaccination with Bacillus Calmette-Guerin (BCG) has limited efficacy, the influence of viable BCG organisms on the induction of CD1b antigen by granulocyte macrophage-colony stimulating factor (GM-CSF) has been tested in adherent mononuclear cells obtained from peripheral blood of healthy donors. The results indicate that the vaccine reduces substantially CD1b induction by GM-CSF. On the other hand, BCG was found to promote a slight increase in the expression of this molecule on target cells not exposed to GM-CSF. Attempts to reverse the antagonistic effects of BCG on GM-CSF with high concentrations of GM-CSF, alone, or associated with IL-4, were unsuccessful. Moreover, mycobacteria suppression by 10 microg/ml of rifampin, did not affect BCG influence on CD1b induction. The present results suggest that mycobacterium-induced impairment of the CD1 system could play a role in the unsatisfactory results obtained with BCG vaccination.