Induction of capsule growth in Cryptococcus neoformans by mammalian serum and CO(2)

The pathogenic fungus Cryptococcus neoformans has a polysaccharide capsule that is essential for virulence in vivo. Capsule size is known to increase during animal infection, and this phenomenon was recently associated with virulence. Although various conditions have been implicated in promoting capsule growth, including CO(2) concentration, osmolarity, and phenotypic switching, it is difficult to reproduce the capsule enlargement effect in the laboratory. In this study, we report that serum can induce capsule growth, and we describe the conditions that induce this effect, not only by serum but also by CO(2). Capsule enlargement was dependent on the medium used, and this determined whether the strain responded to serum or CO(2) efficiently. Serum was most effective in inducing capsule growth under nutrient-limited conditions. There was considerable variability between strains in their response to either serum or CO(2), with some strains requiring both stimuli. Sera from several animal sources were each highly efficient in inducing capsule growth. The cyclic AMP (cAMP) pathway and Ras1 were both necessary for serum-induced capsule growth. The lack of induction in the ras1 mutant was not complemented by exogenous cAMP, indicating that these pathways act in parallel. However, both cAMP and Ras1 were dispensable for inducing a partial capsule growth by CO(2), suggesting that multiple pathways participate in this process. The ability of serum to induce capsule growth suggests a mechanism for the capsular enlargement observed during animal infection.     

Enhancement of peroxisomal enzymes, cytochrome P-452 and DNA synthesis in putative preneoplastic foci of rat liver treated with the peroxisome proliferator nafenopin

The peroxisome proliferator (PP) nafenopin (NAF) enhanced tumordevelopment in rat liver through promotion of a subtype of putativepreneoplastic cell foci, characterized by weak cytoplasmic basophilia(1,2). In order to elucidate the selective growth advantageof these weakly basophilic foci (WBF) we investigated the effectsof NAF on their metabolic phenotype and DNA synthesis. In WBF,as well as in other foci subpopulations and in hepatocellularcarcinomas the occurrence of five NAF-inducible enzymes, i.e.of peroxisomal ß-oxidation (acyl-CoA oxidase, bifunctionalprotein and thiolase), catalase and cytochrome P-452 was studiedby immunohistochemical methods. In untreated livers almost allfoci were stained with the same intensity as the surroundingtissue. When NAF was applied, most of the liver foci showedconsiderably less staining than the non-focal parenchyma inwhich pronounced enzyme induction had occurred. However, thesubpopulation of WBF showed a more heterogeneous pattern ofenzyme expression varying from less to even more than in theadjacent tissue. A similarly broad range of expression of peroxisomalenzymes was found in hepatocellular carcinomas. On average,however, the tumors exhibited less staining and lower activityof peroxisomal ß-oxidation than the surrounding parenchyma.WBF always showed higher rates of DNA synthesis than other focisubtypes and unaltered liver. In     

SHORT COMMUNICATION: Peroxisomal enzyme induction uncoupled from enhanced DNA synthesis in putative preneoplastic liver foci of rats treated with a single dose of the peroxisome proliferator nafenopin

Putative preneoplastic foci of spontaneous origin could be detectedin the livers of 2 year old, untreated male Wistar rats. Theunaltered and preneoplastic hepatocytes showed an identicalexpression of the peroxisomal marker enzyme acyl-CoA oxidase,as determined by immunohistochemical staining. A single doseof the peroxisome proliferator (PP) nafenopin (NAF) inducedthe enzyme predominantly in hepatocytes around the central venulesand cell replication mainly in the periportal areas. However,upon one NAF application almost all of the preneoplastic focishowed a considerably weaker immunoreaction for peroxisomalacyl-CoA oxidase than the surrounding tissue. ConcomitantlyNAF elevated replicative DNA synthesis index in foci up to     

Correlation between antifungal susceptibility testing ofCandida isolates from patients with HIV infection and clinical results after treatment with fluconazole

Summary In an open-label controlled study 23 HIV-infected patients (CDC IV A–E) with documented oropharyngeal candidosis were treated with 100 mg fluconazole orally over 5 days (53 episodes; 1–6 treatments/patient). Efficacy data were compared with a control group of 21 patients who received treatment for 10–21 days with 100 mg fluconazole for candidosis. Candida isolates were repeatedly recovered from patients before and after treatment with fluconazole and antifungal susceptibility testing (microbroth-dilution) was done. Inoculum size, medium pH, incubation time and temperature were standardized. Up to 85% of patients responded to therapy clinically and mycologically.Candida albicans was the most important yeast (86%) isolated from cultures of oral washings. In 90% ofC. albicans isolates MIC to fluconazole were low (1.56 mg/l). Primary resistance to fluconazole was not seen, but secondary resistance occurred in two cases clinically andin vitro (MIC25 mg/l). Short treatment for 5 days was as successful as for 10 to 21 days without leading to significantly more recurrences of oral candidosis in these patients. Selection ofCandida spp. other thanC. albicans (e. g.Candida krusei, Torulopsis glabrata) under repeated fluconazole treatment occurred rarely. One patient developed clinical signs of chronic recurrent candidiasis, where onlyC. krusei could be cultured repeatedly.

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Korrelation zwischen MHK-Bestimmung bei Candida-Isolaten von Patienten mit HIV-Infektion und Therapieverlauf nach Behandlung mit Fluconazol

Zusammenfassung In einer offenen kontrollierten Studie wurde bei 23 HIV-infizierten Patienten (CDC IV A–E) eine dokumentierte oropharyngeale Candidose mit 100 mg Fluconazol oral über 5 Tage behandelt (53 Episoden; 1–6 Episoden/Patient). Die Ergebnisse wurden mit einer Kontrollgruppe verglichen, in der 21 HIV-infizierte Patienten über 10–21 Tage mit 100 mg Fluconazol behandelt wurden. Von den Patienten wurden vor und nach jeder Therapie mit Fluconazol Candida-Isolate gewonnen, differenziert und einer Resistenztestung unterzogen (Mikro-Dilutionstechnik). Für die Resistenztestung wurden Inokulumgröße, pH des Mediums, Inkubationszeit und -temperatur standardisiert. Bis zu 85% der Patienten zeigten klinisch und mykologisch eine Heilung/Besserung.Candida albicans war der am häufigsten isolierte Hefepilz (86%) aus sämtlichen Proben, die mit Mundspülungen gewonnen wurden. 90% allerC. albicans-Isolate warenin vitro Fluconazol-empfindlich (MHK 1,56 mg/l). Eine Primärresistenz gegenüber Fluconazol wurde nicht beobachtet, aber in zwei Fällen trat sowohl klinisch als auchin vitro eine Fluconazol-Resistenz gegenüberC. albicans auf (MHK 25 mg/l). Eine Behandlung der Candidose mit 100 mg Fluconazol über 5 Tage führte zu einer vergleichbaren Heilungs-/Besserungsrate wie über 10–21 Tage, ohne daß die Rezidivrate wesentlich erhöht war. Eine therapiebedingte Selektion von Nicht-albicans-Arten(Candida krusei, Torulopsis glabrata) nach Fluconazol-Behandlung wurde selten beobachtet. Allerdings bestand bei einem Patienten der (klinische) Verdacht auf eine durchC. krusei unterhaltende orale Candidose, da nurC. krusei wiederholt nachgewiesen werden konnte.

     

Response of multicellular tumor spheroids to liposomes containing TNF-α

Summary This publication describes a new model to investigate the influence of tumor necrosis factor- (TNF-) on a three-dimensional glial cell aggregate under defined, standardized, reproducible conditions using the glioma cell line A 172.The cells are initially grown as normal monolayer culture until they reach a cell density of up to 1×10⁶. Subsequently they are grown as spheroids by the liquid overlay technique. Spheroids grown in this way were divided into ten groups of more than 50 cell aggregates. Three groups were coincubated with free TNF- in increasing dosages (100 ng/ml, 200 ng/ml and 1000 ng/ml); three groups were incubated with empty liposomes (0.2 mg/ml, 0.4 mg/ml and 2 mg/ml); three groups received liposomes which had been loaded with TNF-, and one group, which received no treatment, served as control.The diameter of the spheroids ranged from 80 m to 350 m. There was no significant difference in growth between the 3 groups treated with free TNF-. Comparing spheroids treated with TNF- with those which had been coincubated with empty liposomes, there was a significant difference (p<0.001) in growth, which correlated with the amount of liposomes. Similarly, free TNF- had a significantly (P<0.001) stronger growth-inhibiting effect as compared to liposomes loaded with TNF-. Comparing the groups treated with liposomes only to those treated with liposomes loaded with TNF-, the latter exhibited a more marked (although not significantly) growth-inhibiting effect.The preliminary conclusion is that the major growth-inhibiting effect seems to be mediated by the liposomes. This phenomenon is in agreement with results obtained in monolayer cultures.     

Intestinal non-Hodgkin's lymphoma: a multicenter prospective clinical study from the German Study Group on Intestinal non-Hodgkin's Lymphoma.

PURPOSE: Intestinal non-Hodgkin's lymphomas are not well characterized. We therefore studied prospectively their clinical features and response to standardized therapy. PATIENTS AND METHODS: Fifty-six patients with primary intestinal lymphoma were included in a prospective, nonrandomized multicenter study. Lymphoma resection was recommended and staging was performed according to the Ann Arbor classification. Patients were scheduled to receive six cycles of cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) chemotherapy, and at stages EIII to EIV, they received additional involved-field radiotherapy. Corticosteroids were used in patients who could not receive chemotherapy. RESULTS: Thirty-five patients had intestinal T-cell lymphoma (ITCL), 21 patients had intestinal B-cell lymphoma (IBCL; 18 diffuse large-cell lymphomas, two marginal-cell lymphomas, and one follicle-center lymphoma). Thirty-four patients at stages EI to EII (14 ITCL and 20 IBCL) and nine patients at stages EIII to EIV (all ITCL) received chemotherapy. No patient in stages EIII to EIV received radiotherapy, because death occurred in 12 of 14 patients. Two-year cumulative survival in patients with IBCL was 94% (95% CI, 82% to 100%) and higher than in patients with ITCL (28% [95% CI, 13% to 43%]; P <.0001), even when only stages EI to EII were considered (ITCL, 37.5% [95% CI, 16.5% to 58.5%]; P <.0001). IBCL patients compared with ITCL patients were at lower lymphoma stages (P <.01), had higher Karnofsky status (P <.005), had intestinal perforation less often (P <.05), required emergency operation less often (P <.05), received CHOP (P <.05) more often, and reached complete remission (P <.0005) more frequently. CONCLUSION: IBCL patients at stages EI and EII respond well to chemotherapy, but the prognosis and treatment of ITCL patients is unsatisfactory.     

Specialized DNA arrays for the differentiation of pancreatic tumors.

PURPOSE: Malignant tumors of the pancreas are frequently indistinguishable from inflammatory tumors arising in the context of a chronic pancreatitis with the use of conventional imaging techniques. Thus, cytologic analysis of cells obtained by abdominal ultrasound, computed tomography, or endoscopic ultrasound-guided fine needle aspiration biopsy is required for diagnosis. However, the reliability of cytologic analyses of pancreatic fine needle aspirates remains unsatisfactory, with a diagnostic accuracy of < or =80%. The purpose of the current study was therefore to develop a novel diagnostic approach based on expression profiling of biopsy material using a specialized diagnostic cDNA array. EXPERIMENTAL DESIGN: Previous gene expression profiling studies were reevaluated to design a 558-feature diagnostic array. Minimal amounts of residual material from pancreatic cytology samples as well as surgically resected tumor and control tissue specimens were analyzed using the diagnostic array and a newly developed statistical classification system. RESULTS AND CONCLUSIONS: Our diagnostic approach resulted in 95% accurate differentiation between ductal adenocarcinomas and nonmalignant tumors of the pancreas. The diagnostic array, in conjunction with conventional diagnostic procedures, is thus suitable to significantly improve the reliability of pancreatic cancer diagnostics and can be expected to become a valuable new tool in the routine workup of suspect masses in the pancreas.     

Occurrence and elimination of cyanobacterial toxins in two Australian drinking water treatment plants.

In Australian freshwaters, Anabaena circinalis, Microcystis spp. and Cylindrospermopsis raciborskii are the dominant toxic cyanobacteria. Many of these surface waters are used as drinking water resources. Therefore, the National Health and Medical Research Council of Australia set a guideline for MC-LR toxicity equivalents of 1.3 microg/l drinking water. However, due to lack of adequate data, no guideline values for paralytic shellfish poisons (PSPs) (e.g. saxitoxins) or cylindrospermopsin (CYN) have been set. In this spot check, the concentration of microcystins (MCs), PSPs and CYN were determined by ADDA-ELISA, cPPA, HPLC-DAD and/or HPLC-MS/MS, respectively, in two water treatment plants in Queensland/Australia and compared to phytoplankton data collected by Queensland Health, Brisbane. Depending on the predominant cyanobacterial species in a bloom, concentrations of up to 8.0, 17.0 and 1.3 microg/l were found for MCs, PSPs and CYN, respectively. However, only traces (<1.0 microg/l) of these toxins were detected in final water (final product of the drinking water treatment plant) and tap water (household sample). Despite the low concentrations of toxins detected in drinking water, a further reduction of cyanobacterial toxins is recommended to guarantee public safety.     

Risk-Adjusted Cancer Screening and Prevention (RiskAP): Complementing Screening for Early Disease Detection by a Learning Screening Based on Risk Factors

BackgroundRisk-adjusted cancer screening and prevention is a promising and continuously emerging option for improving cancer prevention. It is driven by increasing knowledge of risk factors and the ability to determine them for individual risk prediction. However, there is a knowledge gap between evidence of increased risk and evidence of the effectiveness and efficiency of clinical preventive interventions based on increased risk. This gap is, in particular, aggravated by the extensive availability of genetic risk factor diagnostics, since the question of appropriate preventive measures immediately arises when an increased risk is identified. However, collecting proof of effective preventive measures, ideally by prospective randomized preventive studies, typically requires very long periods of time, while the knowledge about an increased risk immediately creates a high demand for action.SummaryTherefore, we propose a risk-adjusted prevention concept that is based on the best current evidence making needed and appropriate preventive measures available, and which is constantly evaluated through outcome evaluation, and continuously improved based on these results. We further discuss the structural and procedural requirements as well as legal and socioeconomical aspects relevant for the implementation of this concept.