Seizure suppression by adenosine-releasing cells is independent of seizure frequency

PURPOSE: Intraventricular cellular delivery of adenosine was recently shown to be transiently efficient in the suppression of seizure activity in the rat kindling model of epilepsy. We tested whether the suppression of seizures by adenosine-releasing grafts was independent of seizure frequency. METHODS: Adenosine-releasing cells were encapsulated and grafted into the lateral brain ventricle of rats kindled in the hippocampus. During 4 weeks after grafting, electric test stimulations were delivered at a frequency of either once a week or 3 times per week. Seizure activity was evaluated by visual scoring of seizure severity and by the recording of EEGs. RESULTS: Adenosine released from encapsulated cells exerted potent antiepileptic activity for >/=2 weeks. One week after grafting, treated rats displayed a complete protection from clonic seizures, and a protection from focal seizures was observed in the majority of animals. Seizure suppression was accompanied by a reduction of afterdischarges in EEG recordings. The protective efficacy of the grafted cells was the same irrespective of whether electrical test stimulations were delivered 1 or 3 times per week. Rats receiving control grafts continued to display full clonic convulsions. CONCLUSIONS: This study demonstrated that the frequency of test stimulations did not influence the seizure-suppressive potential of adenosine-releasing grafts. Thus the local delivery of adenosine is likely to be effective in seizure control over a threefold range of seizure-discharge frequency.     

Standard versus intensified chemotherapy with granulocyte colony-stimulating factor support in small-cell lung cancer: a prospective European Organization for Research and Treatment of Cancer-Lung Cancer Group Phase III Trial-08923.

PURPOSE: To assess the impact on survival of increasing dose-intensity (DI) of cyclophosphamide, doxorubicin, and etoposide (CDE) in small-cell lung cancer (SCLC). PATIENTS AND METHODS: Previously untreated SCLC patients were randomized to standard CDE (cyclophosphamide 1,000 mg/m(2) and doxorubicin 45 mg/m(2) on day 1, and etoposide 100 mg/m(2) on days 1 to 3 every 3 weeks, for five cycles) or intensified CDE (cyclophosphamide 1,250 mg/m(2) and doxorubicin 55 mg/m(2) on day 1, and etoposide 125 mg/m(2) on days 1 to 3 with granulocyte colony-stimulating factor [G-CSF] 5 micro g/kg/d on days 4 to 13 every 2 weeks, for four cycles). Projected cumulative dose was almost identical on the two arms, whereas projected DI was nearly 90% higher on the intensified arm. Two hundred forty-four patients were enrolled. The first 163 patients were also randomized (2 x 2 factorial design) to prophylactic antibiotics or placebo to assess their impact on preventing febrile leukopenia (FL). This report focuses on chemotherapy DI results. RESULTS: With a median follow-up of 54 months, 216 deaths have occurred. Actually delivered DI on the intensified arm was 70% higher than on the standard arm. Intensified CDE was associated with more grade 4 leukopenia (79% v 50%), grade 4 thrombocytopenia (44% v 11%), anorexia, nausea, and mucositis. FL and number of toxic deaths were similar on the two arms. The objective response rate was 79% for the standard arm and 84% for the intensified arm (P =.315). Median survival was 54 weeks and 52 weeks, and the 2-year survival rates were 15% and 18%, respectively (P =.885). CONCLUSION: A 70% increase of CDE actual DI does not translate into an improved outcome in SCLC patients.     

Threshold temporal integration of chromatic stimuli

We measured colorimetric purity thresholds as a function of stimulus duration for seven wavelengths between 430 and 650 nm. Purity thresholds were measured ina hue substitution mode. The purity-duration function showed decreasing purity as duration was increased to about 640 msec. Functions for different wavelengths could be fit by a fixed chromatic template displaced on the purity axis.Increment thresholds as a function of duration were measured for white and chromatic lights added to a homogenous white stimulus field. The “white” function showed no integration beyond 160 msec and was fit by an achromatic template. The wavelength functions were not parallel; wavelengths at the spectral extremes showed longer integration times, similar to the purity-duration functions. Increment data could be fit by a vector sum of chromatic and achromatic templates.     

Spectral sensitivity of the foveal cone photopigments between 400 and 500 nm

A comparison was made between the shape of the iodopsin absorption spectrum calculated for appropriate optical density to (1) a set of König-type fundamentals in which the tritanopic copunctal point was set on the alychne and (2) data obtained from red-green dichromats using high intensity heterochromatic flicker procedures which eliminated participation by the short-wavelength sensitive mechanism. The transformation of normal color mixture data resulted in two fundamentals which gave a reasonable prediction of the tritanopic coefficients. The dichromaticHFP data corrected individually to average macular pigment agreed with their respective fundamental above 430 nm. TheHFP data and transformation were converted to a retinal level, quantized and plotted as a function of wavenumber. For the middle-wavelength-sensitive mechanism, the protanopicHFP data and its König-type fundamental agreed with the predicted absorption spectrum above 460 nm. The deviations below 460 nm had the shape of the lens absorbance curve. For the long-wavelength sensitive mechanism, the deuteranopic data and its König-type fundamental agreed with the predicted absorption spectrum above 520 nm. The deviations below 520 nm could not be fit solely by the lens absorbance factor used above, but needed in addition, added macular pigment of optical density at 460 nm ofca. 0.12. This result was checked by calculating predicted tritanopic coefficients for the two predicted absorption spectra, when the long-wavelength sensitive spectrum was screened by a slight amount (o.d. of 0.12 at 460 nm) of macular pigment. These predicted coefficients agreed with the Wright tritanopic coefficients. We conclude (a) that the shape of the iodopsin absorption spectrum provides a reasonable basis for computation of absorption spectra of the middleand long-wavelength sensitive cone pigments and (b) that long-wavelength sensitive cones of deuteranopes. tritanopes, and normal trichromats are subject to a selective screening filter of optical density at 460 nm of 0.12 and spectral shape similar to macular pigment.     

IGM is required for efficient complement mediated phagocytosis of apoptotic cells in vivo

A variety of complement components have been detected on apoptotic cells and proposed to facilitate recognition and/or ingestion by phagocytes. The triggers for complement activation remain uncertain. To determine the role of IgM in classical pathway activation and clearance of apoptotic cells in vitro and in vivo, we quantified these parameters in mice deficient in serum IgM (sIgM). Phagocytosis by bone marrow-derived macrophages of apoptotic cells incubated with serum deficient in sIgM was markedly reduced, similar to apoptotic cells incubated with C1q deficient serum in vitro. Similarly, intraperitoneal clearance of apoptotic cells and cellular C3 deposition were significantly reduced in mice deficient in sIgM compared to wild-type mice. Clearance and C3 deposition were reconstituted by addback of IgM. In mice deficient in both sIgM and Clq, addback of both serum factors was required for restoration of clearance. These findings indicate that, on a quantitative basis, sIgM is a potent factor required for intraperitoneal phagocytosis of apoptotic cells, and further demonstrate that IgM and C1q work in concert to activate complement, resulting in C3 deposition on the apoptotic cell surface and ultimately, efficient clearance of the apoptotic cell by macrophages.     

Suppression of kindled seizures by paracrine adenosine release from stem cell-derived brain implants

PURPOSE: Stem cells and their derivatives have emerged as a promising tool for cell-based drug delivery because of (a) their unique ability to differentiate into various somatic cell types, (b) the virtually unlimited donor source for transplantation, and (c) the advantage of being amenable to a wide spectrum of genetic manipulations. Previously, adenosine-releasing embryonic stem (ES) cells have been generated by disruption of both alleles of adenosine kinase (Adk-/-). Lack of ADK did not compromise the cells' differentiation potential into embryoid bodies or glial precursor cells. The aim of the present study was to investigate the potential of differentiated Adk-/- ES cell progeny for seizure suppression by paracrine adenosine release. METHODS: To isolate paracrine effects of stem cell-derived implants from effects caused by network integration, ES cell-derived embryoid bodies and glial precursor cells were encapsulated into semipermeable polymer membranes and grafted into the lateral brain ventricles of kindled rats. RESULTS: While seizure activity in kindled rats with wild-type Adk+/+ implants remained unaltered, rats with adenosine-releasing Adk-/- ES cell-derived implants displayed transient protection from convulsive seizures and a profound reduction of afterdischarge activity in EEG recordings. Long-term seizure suppression was precluded by limited viability of the encapsulated cells. CONCLUSIONS: We thereby provide a proof-of-principle that Adk-/- ES cell-derived brain implants can suppress seizure activity by a paracrine mode of action. Adk-deficient stem cells therefore represent a potential tool for the treatment of epileptic disorders.     

Starting a crossover kidney transplantation program in the Netherlands: ethical and psychological considerations

On April 15th, 2003, the first crossover kidney transplantation took place in The Netherlands. In September of the same year, a national database was established to facilitate kidney exchange between two donor-recipient couples. During 2004, kidneys from living donors will be exchanged between the seven university medical centers in The Netherlands. One of the conditions for successfully implementing this program was the need to address the ethical and psychologic implications involved. In this article we will discuss the ethical and psychologic considerations that are accompanying the practical preparations for the first Dutch crossover transplantation program. We identified five topics of interest: the influence of "donation by strangers" on the motivation and willingness of donor-patient couples, the issue of anonymity, the loss of the possibility of "medical excuses" for unwilling donors, the view that crossover is a first step to commercial organ trade, and the interference with existing organ donation programs. We concluded that whether viewed separately or in combination, these issues do not impede the efficient organization of a crossover program or raise worrying ethical issues.     

The complex between urokinase-type plasminogen activator (uPA) and its type-1 inhibitor (PAI-I) independently predicts response to first-line endocrine therapy in advanced breast cancer

It has been shown that urokinase-type plasminogen activator (uPA) and its main inhibitor (PAI-I) have predictive value for therapy success in advanced breast cancer. Levels of the complex between uPA and PAI-I, formed when both molecules are in their active form, might have superior predictive power. Here, we investigate the association between levels of uPA:PAI-I complex and rate of response to first-line systemic therapy for advanced breast cancer. Tumor tissues of 170 patients with advanced breast cancer were analyzed for uPA:PAI-I complex concentrations using a quantitative enzyme-linked immunosorbent assay. The patients received either endocrine therapy (n=96) or chemotherapy (n=74) as first-line treatment after diagnosis of advanced disease. Of the endocrine treated patients, those with high levels of uPA:PAI-I complex showed a shorter progression-free survival (PFS) compared to patients with lower uPA:PAI-I complex levels (P=0.035). Furthermore, in the multivariate regression analysis a significant lower rate of response to first-line endocrine therapy was found in patients with high uPA:PAI-I complex levels compared to patients with low uPA:PAI-I complex levels (odds ratio (OR)=0.27, 95% CI, 0.09-0.59, P=0.018), in addition to the predictive impact of the steroid hormone receptor (ER/PgR) status (OR=2.68, 95% CI, 1.08-6.63, P=0.033). Complex levels did not predict efficacy of chemotherapy in patients with advanced breast cancer. The results show that the plasminogen activation system affects the response to endocrine therapy independent of steroid hormone receptor status and may be of help to further refine the indication for this treatment in individual patients. Further studies are warranted to explain this underlying resistance to endocrine therapy when uPA:PAI-I levels are high.