Wnt activation promotes neuronal differentiation of glioblastoma

One of the biggest challenges in tumour research is the possibility to reprogram cancer cells towards less aggressive phenotypes. In this study, we reprogrammed primary Glioblastoma multiforme (GBM)-derived cells towards a more differentiated and less oncogenic phenotype by activating the Wnt pathway in a hypoxic microenvironment. Hypoxia usually correlates with malignant behaviours in cancer cells, but it has been recently involved, together with Wnt signalling, in the differentiation of embryonic and neural stem cells. Here, we demonstrate that treatment with Wnt ligands, or overexpression of β-catenin, mediate neuronal differentiation and halt proliferation in primary GBM cells. An hypoxic environment cooperates with Wnt-induced differentiation, in line with our finding that hypoxia inducible factor-1α (HIF-1α) is instrumental and required to sustain the expression of β-catenin transcriptional partners TCF-1 and LEF-1. In addition, we also found that Wnt-induced GBM cell differentiation inhibits Notch signalling, and thus gain of Wnt and loss of Notch cooperate in the activation of a pro-neuronal differentiation program. Intriguingly, the GBM sub-population enriched of cancer stem cells (CD133⁺ fraction) is the primary target of the pro-differentiating effects mediated by the crosstalk between HIF-1α, Wnt, and Notch signalling. By using zebrafish transgenics and mutants as model systems to visualize and manipulate in vivo the Wnt pathway, we confirm that Wnt pathway activation is able to promote neuronal differentiation and inhibit Notch signalling of primary human GBM cells also in this in vivo set-up. In conclusion, these findings shed light on an unsuspected crosstalk between hypoxia, Wnt and Notch signalling in GBM, and suggest the potential to manipulate these microenvironmental signals to blunt GBM malignancy.

Evaluation of guidelines for the use of telemetry in the non-intensive-care setting

To determine if the American College of Cardiology (ACC) cardiac monitoring guidelines accurately stratify patients according to their risks for developing clinically significant arrhythmias in non-intensive-care settings, we conducted a prospective cohort study of 2,240 consecutive patients admitted to a non-intensive-care telemetry unit over 7 months. Sixty-one percent of patients were assigned to ACC class I (telemetry indicated in most patients), 38% to class II (telemetry indicated in some), and 1% to class III (telemetry not indicated). Arrhythmias were detected in 13.5% of the class I patients, 40.7% of the class II patients, and 12% of the class III patients (p <.001). Telemetry detected an arrhythmia resulting in transfer to an intensive care unit in 0.4% of the class I patients, 1.6% of the class II patients, and none of the class III patients (p =.006). Telemetry led to a change in management for 3.4% of the class I patients, 12.7% of the class II patients, and 4% of the class III patients (p <.001). When patients with chest pain as the reason for admission were moved from class I to class II and patients with arrhythmias as the reason for admission were moved from class II to class I, more arrhythmias and more clinically significant arrhythmias occurred in class I patients and the trends from class I to class III were more consistent with the purpose of the guidelines. These findings indicate that when the ACC guidelines are reexamined, consideration should be given to changing them so they are more useful in non-intensive-care settings.

Role of telemetry monitoring in the non-intensive care unit

To determine the outcomes of patients admitted to a non-intensive care telemetry unit and to assess the role of telemetry for guiding patient management decisions, data from 2,240 patients admitted to a telemetry unit were collected prospectively during 7 months. Physicians recorded the outcomes (intensive care unit transfer and mortality) and assessed whether telemetry assisted in guiding patient management. Indications for admission to the telemetry unit included chest pain syndromes (55%), arrhythmias (14%), heart failure (12%), and syncope (10%). Telemetry led to direct modifications in management in 156 patients (7%; 95% confidence interval [CI] 5.9% to 8%). Telemetry was perceived as useful but did not alter management for 127 patients (5.7%; 95% CI 4.7% to 6.6%). Two hundred forty-one patients were transferred to an intensive care unit from the telemetry unit (10.8%; 95% CI 9.5% to 12%). Nineteen patients (0.8% of all admissions; 95% CI 0.5% to 1.2%) were transferred because of an arrhythmia identified by telemetry. Routine transfer after cardiac revascularization or surgery accounted for 134 transfers; clinical deterioration accounted for 88 transfers. There were 20 deaths in the unit (0.9%; 95% CI 0.5% to 1.3%): 4 of the 20 deaths occurred while patients were being monitored. The role of telemetry in guiding patient management may be overestimated by physicians, since it detected significant arrhythmias that led to change in medications or urgent interventions in a small fraction of patients.

The evolving pattern of digoxin intoxication: observations at a large urban hospital from 1980 to 1988

Digoxin intoxication has been reported to be a common adverse drug reaction with an in-hospital incidence of 6% to 23% and an associated mortality rate as high as 41%. A retrospective review was conducted to assess the accuracy of diagnosis, the morbidity and mortality of digoxin intoxication, and its incidence in hospitalized patients with heart failure. We reviewed the medical records of 219 patients discharged with the diagnosis of digoxin intoxication between 1980 and 1988. Patients were classified as follows: (1) Definite intoxication--patients with symptoms and/or arrhythmias suggestive of digoxin intoxication that resolved after discontinuation of digoxin; (2) possible intoxication--patients with symptoms and/or arrhythmias suggestive of digoxin intoxication in the absence of documented resolution after discontinuation of digoxin, or the presence of other clinical illnesses that could possibly account for those findings; (3) no intoxication--patients whose symptoms or ECG abnormalities were clearly explained by other associated clinical illnesses and persisted after withdrawal of digoxin. We identified only 43 patients (20%) with definite intoxication. The majority of patients discharged with the diagnosis of digoxin intoxication (133 or 60%) were classified as possibly digoxin intoxicated, and 43 patients (20%) had no clinical evidence to support this diagnosis. To estimate the incidence of digoxin intoxication, we also reviewed the medical records of 994 patients admitted in 1987 with heart failure. Of these, 563 were receiving digoxin and in 27 the diagnosis of digoxin intoxication was made by their clinicians. Our review showed that only four were definitely intoxicated (0.8%), and the diagnosis could not be excluded in another 16 (4%).(ABSTRACT TRUNCATED AT 250 WORDS)

Fructose-1,6-diphosphate counteracts ethanol-stimulated calcium uptake in isolated BHK cells

Ethanol increases the uptake of 45Ca by isolated baby hamster kidney (BHK) cells in vitro. The effect is dependent on ethanol and 45Ca++ concentration and on the incubation time. Fructose-1,6-diphosphate (FDP) added at different concentration during the pre-incubation exerts a protective effect through a membrane-stabilizing action which is consistent with its in vivo anti-alcohol activity documented in previous studies.

Baroreflex function after therapy withdrawal in patients with essential hypertension

1. Baroreceptor sensitivity and vascular reactivity to noradrenaline were assessed in patients with essential hypertension chronically treated with diuretics during treatment and 6-8 weeks after its withdrawal. 2. Stopping diuretics was followed by an increase in mean arterial blood pressure and vascular reactivity, while baroreceptor sensitivity decreased. 3. Baroreceptor sensitivity during treatment correlated directly with the time during which patients remained normotensive after stopping diuretics. 4. An inverse correlation was found between vascular reactivity and baroreceptor sensitivity after diuretic withdrawal and between the patients' age and baroreceptor sensitivity during diuretic therapy. 5. We conclude that the impairment of baroreceptor sensitivity after stopping diuretic therapy could result in an enhanced vascular response to noradrenaline, and a sensitive baroreflex could contribute to the control of blood pressure during diuretic treatment and buffers the return of high blood pressure when diuretics are stopped.

Effect of indapamide on the baroreceptor reflex in essential hypertension

The effect of chronic treatment with indapamide on blood pressure (BP), baroreceptor sensitivity (BRS) and vascular reactivity (VR) were investigated in 10 patients with essential hypertension. After 3 months of therapy with indapamide 2.5 mg/d the mean arterial pressure (MAP) had decreased from 135 +/- 6 to 112 +/- 2 mmHg (p less than 0.001); the heart rate (HR) had not changed, VR had decreased from 6.1 +/- 1.2 to 4.8 +/- 1.8 (pg . min . kg)-1 (p less than 0.05), and BRS had increased from 8.3 +/- 3.7 to 12.2 +/- 5.3 ms/mmHg (p less than 0.005), with a leftshift of the relationship between BP and heart period. An inverse correlation was found between the pre-treatment systolic blood pressure and the change in baroreceptor sensitivity after indapamide (r = 0.59; p less than 0.05). In conclusion, chronic treatment with indapamide enhances BRS and resets the reflex. The resetting may account for the lack of tachycardia at rest observed after treatment with indapamide. The mechanism by which indapamide interferes with the baroreceptor reflex requires further investigations.