The identification of a fraction of cancer stem cells (CSCs) associated with resistance to chemotherapy in most solid tumors leads to the dogma that eliminating this fraction will cure cancer. Experimental data has challenged this simplistic and optimistic model. Opposite to the classical cancer stem cell model, we introduced the stemness phenotype model (SPM), which proposed that all glioma cells possess stem cell properties and that the stemness is modulated by the microenvironment. A key prediction of the SPM is that to cure gliomas all gliomas cells (CSCs and non-CSCs) should be eliminated at once. Other theories closely resembling the SPM and its predictions have recently been proposed, suggesting that the SPM may be a useful model for other type of tumors. Here, we review data from other tumors that strongly support the concepts of the SPM applied to gliomas. We include data related to: (1) the presence of a rare but constant fraction of CSCs in established cancer cell lines, (2) the clonal origin of cancer, (3) the symmetrical division, (4) the ability of "non-CSCs" to generate "CSCs," and (5) the effect of the microenvironment on cancer stemness. The aforenamed issues that decisively supported the SPM proposed for gliomas can also be applied to breast, lung, prostate cancer, and melanoma and perhaps other tumors in general. If the glioma SPM is correct and can be extrapolated to other types of cancer, it will have profound implications in the development of novel modalities for cancer treatment.

Background: Epidemiologic evidence of surgical transmission of sporadic Creutzfeldt-Jakob disease (sCJD) remains controversial. Methods: From Danish and Swedish registries we selected 167 definite and probable sCJD cases (with onset between 1987 and 2003) and 3,059 controls (835 age-, sex-, and residence-matched, and 2,224 unmatched). Independent of case/control status, surgical histories were obtained from National Hospital Discharge Registries. Surgical procedures were categorized by body system group and lag time to onset of sCJD. Exposure frequencies were compared using logistic regression. Results: A history of any major surgery, conducted ≧20 years before sCJD onset, was more common in cases than both matched (OR = 2.44, 95% CI = 1.46–4.07) and unmatched controls (OR = 2.25, 95% CI = 1.48–3.44). This observation was corroborated by a linear increase in risk per surgical discharge (OR = 1.57, 95% CI = 1.13–2.18; OR = 1.50, 95% CI = 1.18–1.91). Surgery of various body systems, including peripheral vessels, digestive system and spleen, and female genital organs, was significantly associated with increased sCJD risk. Conclusions: A variety of major surgical procedures constitute a risk factor for sCJD following an incubation period of many years. A considerable number of sCJD cases may originate from health care-related accidental transmission.

BACKGROUND:In this preparatory phase of a case-control study, we propose and evaluate a new tool for classifying surgical procedures (SPs) in categories useful for epidemiologic research on surgical transmission of sporadic Creutzfeldt-Jakob disease (sCJD).METHODS:All SPs reported to the Swedish National Hospital Discharge Registry in the period 1974-2002, and undergone by 212 Swedish patients with registered diagnosis of CJD at death, hospital discharge or notification, in the period 1987-2002, 1060 age-, sex- and residence-matched controls and 1340 randomly chosen population controls, were reclassified into one of six categories of hypothetical transmission risk level. For that purpose the following two attributes were used: non-disposable instruments involved; and highest assigned ad-hoc risk level for four tissues or anatomical structures contacting such instruments.RESULTS:A total of 1170 different SP codes were reclassified as follows: 3.1% in the high-risk, 59.1% in the lower-risk, 24.4% in the lowest-risk, and 2.1% in the no-risk groups, with 11.3% procedures negatively defined by rubric as "other than..." being assigned to two spurious diluted-high and diluted-lower risk categories. The high-risk group mainly comprised neurosurgical (53%) and ophthalmic (39%) procedures. Sensitivity of neurosurgery and of ophthalmic surgery excluding neurosurgery, for the high- and diluted-high risk vs. other categories was 46% and 84%, while specificity was 98% and 95%, respectively. Sensitivity analysis based on these indices revealed that non-significant odds ratio effects of 1.4 and 1.3 for neurosurgery and ophthalmic surgery corresponded to statistically significant values of 5.1 after reclassification.CONCLUSIONS:This classification might contribute to quantify effects masked by use of body-system SP-categories in case-control studies on sCJD transmission by surgery.

The cerebrospinal fluid (CSF) protein patterns, in ischemic cerebrovascular disease (ICD), of varying extension were studied by isoelectric focusing (IEF) in 100 patients at different intervals after the onset of symptoms. The diagnoses were based on conventional clinical examinations and CSF spectrophotometry in all cases. Computed tomography was performed on 52 cases.

The long-term safety and efficacy of the catechol-O-methyltransferase (COMT) inhibitor entacapone was investigated in a 3-year open-label extension of the 6-month double-blind placebo-controlled Nordic (NOMECOMT) study. After a wash-out following this study, 132 patients with Parkinson's disease (PD) experiencing motor fluctuations treated with levodopa/dopa decarboxylase (DDC) inhibitor received additional therapy with entacapone 200 mg, administered with each dose of levodopa. The most common adverse events (AEs) were insomnia (30%), dizziness (20%), nausea (20%), aggravated parkinsonism (17%) and hallucinations (14%). Only 19 (14%) patients discontinued because of AEs. Most dopaminergic AEs occurred shortly after initiation of entacapone, and these could be managed by levodopa down-adjustment. The mean duration of benefit of a single dose of levodopa increased significantly from 2.1 to 2.8 h (P < 0.01) at 3 months and remained prolonged for the whole study. At the end of the study, the mean daily dose of levodopa was significantly decreased from baseline (from 737 to 696 mg; P < 0.05). The patients' global assessment indicated that 69% of patients improved when given entacapone and this proportion was maintained until the end of the study (64%). There was a significant worsening of disability upon withdrawal of entacapone. In conclusion, entacapone given in combination with levodopa, has a good long-term safety profile and a sustained beneficial effect in patients with PD with motor fluctuations.

The effect of roscovitine, a purine analogue and cyclin dependent kinase inhibitor, on DNA synthesis rate in tissue mini-units obtained from human cervical cancers was investigated. Roscovitine (100 μM) gave a DNA synthesis rate inhibition by 61% (P<0.0001; range 23–93%) within 30 min of incubation. This inhibitory effect was concentration-dependent. The results suggest that the inhibition of tumor DNA synthesis rate is due to a direct effect on the DNA synthesis machinery via presently unknown mechanisms. In addition, the potential application of CDKs inhibitors as preventive agents is discussed.

The drug disulfiram is a thiol-reacting drug that is relatively nontoxic when used alone and has been used in the therapy of alcohol abuse for more than 40 years. Several effects of this drug have been reported for DNA synthesis and cell proliferation. In this study, the inhibitory effect of disulfiram on topoisomerase I and II activity was investigated by measuring the relaxation of superhelical plasmid pBR322 DNA. Disulfiram (1-100 microM) inhibited topoisomerase I and II in a concentration-dependent manner (IC(50) congruent with 42 +/- 8 and 30 +/- 9 microM, respectively). Consistent with the assumption that a thiol residue is involved, dithiothreitol (1 mM) markedly prevented the inhibitory effect of disulfiram on the activity of both classes of topoisomerases. These findings might explain certain aspects of disulfiram toxicity and encourage new studies to determine the usefulness of this drug and its analogues as antineoplastic agent.

The brain is the exclusive or almost exclusive site of formation of 24S-hydroxycholesterol and we have shown that the circulating level of 24S-hydroxycholesterol is dependent upon the relation between cerebral production and hepatic clearance. In the present work we determined plasma levels of 24S-hydroxycholesterol in patients with various neurological diseases. Eleven subjects with brain death occurring 6-10 h before collection of the plasma samples had markedly reduced circulating levels of 24S-hydroxycholesterol (-43%, P<0.001). Patients with advanced Alzheimer's disease and cerebral inflammatory diseases had slightly lower levels of 24S-hydroxycholesterol in plasma when compared to matched controls. Patients with acute ischemic stroke, multiple sclerosis and primary brain tumors had levels not significantly different from those of controls. The conditions leading to reduced plasma levels of 24S-hydroxycholesterol had no significant effect on plasma levels of another side-chain oxidized oxysterol, 27-hydroxycholesterol. Except for conditions characterized by very marked destruction of the central nervous system, different severe neurological diseases seem to have relatively small effects on the flux of 24S-hydroxycholesterol from the brain.

By using tissue miniunits, protein kinase modulators, and topoisomerase inhibitors in short-term incubation (0–90 min) we studied (1) the role of protein phosphorylation in the immediate control of DNA replication in the developing rat cerebral cortex and (2) the mechanism of action for genistein-mediated DNA synthesis inhibition. Genistein decreased the DNA synthesis within less than 30 min. None of the other protein kinase inhibitors examined (herbimycin A, staurosporine, calphostin-C) or the protein phosphatase inhibitor sodium orthovanadate inhibited DNA synthesis and they did not affect the genistein-mediated inhibition. The selective topoisomerase inhibitors camptothecin and etoposide decreased the DNA synthesis to an extent similar to that of genistein and within less than 30 min. In addition, the effects of these substances on topoisomerase I and II were studied. Etoposide and genistein but not herbimycin A, staurosporine, or calphostin-C strongly inhibited the activity of topoisomerase II. Our results (1) strongly suggest that the net rate of DNA replication during the S phase of the cell cycle is independent of protein phosphorylation and (2) indicate that the early inhibitory effect of genistein on DNA synthesis is mediated by topoisomerase II inhibition rather than protein tyrosine kinase inhibition.

The early effect of 1-100 microM roscovitine, a purine analogue and cyclin-dependent kinase inhibitor, was studied on tissue specimens from eight human malignant gliomas. The tissue was incubated immediately after resection with DMEM containing [3H]methylthymidine plus vehicle alone or the proper concentration of roscovitine for 30-90 min. The DNA synthesis rate was assessed by measurement of [3H]methylthymidine incorporation into trichloroacetic acid insoluble material/mg protein/min. In all gliomas, 100 microM roscovitine inhibited DNA synthesis by 71-97% (average 89 +/- 8%, p<0.0001). This inhibitory effect of roscovitine appeared within 30 min of incubation and was concentration dependent.

A proliferation assay based on the production of mini-units of tissue was adopted and modified for the simultaneous determination of cell proliferation rate and the effect of genistein in rat cerebral cortex. Mini-units of tissue were produced from rat cerebral cortex immediately after killing the animal and incubated with culture medium containing 3H-methyl-thymidine during 90 min. The proliferation rate was assessed by measurement of 3H-methyl-thymidine incorporation into trichloroacetic acid insoluble material/mg of protein/min. The mini-unit method preserves the neural-cell topological relation existing in vivo and, in addition, has several additional advantages: (1) the short incubation time required limits the metabolic changes, (2) the sensitivity to drugs can be assessed simultaneously with the cell proliferation rate, (3) the complete procedure can be performed within 4-6 h, and (4) many experiments can be performed with the tissue from one animal. Genistein in doses from 10 to 100 microM inhibited cell proliferation in a concentration-dependent manner. The percentage of inhibition was highest in young animals and decreased with increasing age. This method is a powerful tool for the study of drugs with short-time onset mechanisms of action and can be useful for the screening of new drugs.

The effects of the cyclin-dependent kinase (CDK) inhibitors olomoucine and roscovitine on DNA synthesis were studied using short time incubation (30-90 minutes). Both purine analogues at concentrations from 1-100 μM decreased the DNA synthesis of rat brain cortex in a dose-dependent manner and the maximum effect occurred within 30 min of incubation. Staurosporine, another potent CDK inhibitor did not affect the DNA synthesis in the concentration range 1-250 nM. These results indicate that olomoucine and roscovitine block DNA synthesis by a mechanism independent of CDK inhibition. We propose that the cellullar effects of olomuocine and roscovitine on the cell cycle are at least in part due to this early inhibitory effect on DNA synthesis.

Objective: To study the effect and safety of entacapone as an adjunct to levodopa treatment in patients with PD with wearing-off motor fluctuations. Background: Entacapone is a catechol-O-methyltransferase (COMT) inhibitor that has been shown to increase the area under the concentration-time curve of plasma levodopa by decreasing its systemic elimination, thereby promoting and improving therapeutic response to it. Methods: A total of 171 parkinsonian patients with wearing-off-type motor fluctuations participated in a 6-month randomized, placebo-controlled, double-blind, parallel-group study. The extent of therapeutic response was elicited in the first hand with home diary recordings of "on" and "off" times by the patient and with Unified Parkinson's Disease Rating Scale scoring by the examiner. The patients took either 200 mg entacapone or identical placebos concomitantly with each daily levodopa dose (four to 10 times a day). Results: Patients' home diaries indicated that entacapone increased the mean (± SD) "on" time significantly (9.3 ± 2.2 to 10.7 ± 2.2 hours; p < 0.01) and correspondingly decreased the "off" time significantly (5.3 ± 2.2 to 4.2 ± 2.2 hours; p < 0.001). The average benefit derived from a daily levodopa dose as related by the patients was increased significantly (p < 0.01). The daily levodopa dose was reduced significantly in the entacapone group, the difference between the groups being 102 mg (p < 0.01). The entacapone-derived increase in the benefit from levodopa was lost almost completely following its withdrawal. Entacapone was well tolerated. Dopaminergic adverse events, which increased, were ameliorated by reducing the levodopa dose. Diarrhea was the most common nondopaminergic adverse event. Conclusions: Long-term entacapone treatment effectively prolonged the beneficial response to levodopa in parkinsonian patients with the wearing-off phenomenon. The improvement occurred irrespective of the reduction of the levodopa dose.

We have investigated whether side chain-hydroxylated cholesterol species are important for elimination of cholesterol from the brain. Plasma concentrations of 24-hydroxycholesterol (24-OH-Chol) in the internal jugular vein and the brachial artery in healthy volunteers were consistent with a net flux of this steroid from the brain into the circulation, corresponding to elimination of approximately 4 mg cholesterol during a 24-h period in adults. Results of experiments with rats exposed to 18O2 were also consistent with a flux of 24-OH-Chol from the brain into the circulation. No other oxysterol measured showed a similar behavior as 24-OH-Chol. These results and the finding that the concentration of 24-OH-Chol was 30- to 1500-fold higher in the brain than in any other organ except the adrenals indicate that the major part of 24-OH-Chol present in the circulation originates from the brain. Both the 24-OH-Chol present in the brain and in the circulation were the 24S-stereoisomer. In contrast to other oxysterols, levels of plasma 24-OH-Chol were found to be markedly dependent upon age. The ratio between 24-OH-Chol and cholesterol in plasma was approximately 5 times higher during the first decade of life than during the sixth decade. There was a high correlation between levels of 24-OH-Chol in plasma and cerebrospinal fluid. It is suggested that the flux of 24-OH-Chol from the brain is important for cholesterol homeostasis in this organ.

The levels of excitatory amino acids (EAA), monoamines, neuropeptide Y (NPY) and cholecystokinin were quantitated in cerebrospinal fluid (CSF) in the patients with Parkinson's disease (PD). The results accumulated showed that the levels of aspartate (ASP), glutamate (GLU) and noradrenaline (NA) in the CSF were higher while that of dopamine (DA) and cholecystokinin octapeptide (CCK-8) were lower in untreated PD patients. There were no change in NPY and 5-hydroxy tryptamine (5-HT) levels in L-DOPA treated or untreated PD patients. With the exception of the low level of CCK-8 and the unchanged NPY, these alterations in ASP, GLU and DA levels were partially or completely reversed after treatment with L-DOPA. These results suggest that GLU secretion is enhanced in PD and that DAergic treatment normalizes not only DA, but also ASP and GLU levels. These findings support the hypothesis that GLU and DA interact in the human brain. The unchanged levels of NPY and 5-HT reflect non-depression state in PD patients.