Evaluation of mag-fura-5, the new fluorescent indicator for free magnesium measurements

The new fluorescent indicator, mag-fura-5, was evaluated for its ability to measure accurately physiological changes in cytosolic free magnesium. The apparent dissociation constants (K _d) of the fluorochrome for Mg²⁺, Mg²⁺/EGTA and Ca²⁺/EGTA solutions were 14.7 mM, 15.4 mM, and 1.8 mM respectively. The calculated difference in the fluorescence ratios and in the resulting pMg between the standards with low-Ca²⁺ or low H⁺ backgrounds and the corresponding samples with approximately physiological levels were not significant. In contrast, the changes due to an increased Ca²⁺ or H⁺ content were statistically significant, with mean pMg differences of 0.10±0.09 (P<0.02) and 0.33±0.26 (P<0.01) respectively. Repetitive measurements on 3 consecutive days yielded comparable data with differences not exceeding 4%. Because of the good reproducibility, it is suggested that the new fluoresecent probe may be suitable for free cytosolic magnesium determinations in isolated cells.     

Intrahippocampal Injection of Endothelin-1: A New Model of Ischemia-induced Seizures in Immature Rats

Summary:  The goal of this study was to develop a new model of ischemia-induced seizures in immature rats using injection of vasoconstrictor Endothelin-1 (ET-1) into the brain. ET-1 (10, 20, or 40 pmol) was infused into the left dorsal hippocampus of freely moving Wistar rats 12 (P12) and 25 (P25) days old. Animals were then video/EEG-monitored for 100 min and monitoring was repeated 22 h later. Parameters of electrographic seizures (frequency and mean duration) as well as pattern of their behavioral correlates were evaluated. The pattern of behavioral seizures was used to develop model-specific scoring system. Cresyl violet and Fluoro Jade-B-staining were used to evaluate brain damage. Extension of the lesion was correlated with seizure severity. After ET-1-injection, seizures occurred in 83–100% animals of all age-and-dose groups and persisted for 24 h except P12 rats with 10 pmol. There were no differences in average seizure duration (18–40 s) or seizure frequency (3–7 seizures/100 min) among individual dose-groups. Between the 1st and 2nd observation period, total seizure duration decreased in 71% of P12 and 47% of P25 rats. Electrographic seizure activity was most frequently accompanied by clonus, incidence of more severe convulsions (barrel rolling or generalized clonic seizures) increased with dose of ET-1. Morphologic examination did not reveal any dose-related difference in damage severity, hippocampal damage was however more extensive in P12 compared to P25 animals. Seizure severity correlated positively with severity of the damage in both age groups. Our study presents focal injection of ET-1 into the brain as a new and practical model of ischemia-induced seizures in immature rats.     

Long-term results of the Cox-Maze III procedure for persistent atrial fibrillation associated with rheumatic mitral valve disease: 10-year experience.

OBJECTIVE: We evaluated the long-term results of the Cox-Maze III procedure (CM-III) for persistent atrial fibrillation (AF) associated with rheumatic mitral valve (MV) disease. METHODS: We analyzed 127 patients who underwent the CM-III combined with a rheumatic MV procedure between 1994 and 2004. In-hospital mortalities were excluded from the study. RESULTS: There were 10 late deaths and the mean follow-up duration was 7.1+/-2.8 years (range, 13 months to 11.5 years). Normal sinus rhythm was restored in 88.2% (112/127) after the CM-III. Right atrial contractility was demonstrable in 100% (112/112) and left atrial contractility in 68.8% (77/112) of the patients restored to sinus rhythm. Fifteen patients never regained sinus rhythm after the CM-III (AF treatment failure). Permanent pacemakers were implanted in 4.7% (6/127) of the patients during the follow-up. Late recurrence of AF developed in 34 of 112 patients at 44+/-27 months postoperatively, and sinus rhythm was restored in 29 of 34 patients by administration of an antiarrhythmic medication. Independent risk factors for late AF recurrence were longer duration of AF (>60 months) (odds ratio (OR)=2.758, p=0.025), increased left atrial size (OR=1.113, p=0.004). Freedom from AF recurrence was 93% at 1-year, 82% at 3 years, 71% at 5 years, and 63% at 7 years. Risk factors for AF treatment failure were longer duration of AF (>60 months) (p<0.001) and increased patient age (p=0.030). A higher prevalence of significant late tricuspid regurgitation was observed in patients with AF treatment failure and those with late AF recurrence. CONCLUSIONS: The CM-III for persistent AF associated with rheumatic MV disease demonstrated a progressively decreased cure rate during the follow-up period. Early surgical therapy, aggressive left atrial reduction, and correction of tricuspid regurgitation at the time of surgery may increase the long-term success rate.     

Care pathways for acute stroke care and stroke rehabilitation: from theory to evidence.

Care pathways aim to promote evidence- and guideline-based care, improve the organisation and efficiency of care, and reduce cost. In the past decade, care pathways have been increasingly implemented as a tool in acute stroke care and stroke rehabilitation. In the most recent Cochrane systematic review, which included three randomised and 12 non-randomised studies, patient management with stroke care pathways was found to have no significant benefit on functional outcome, and patient satisfaction and quality of life might actually be worse. On the other hand, it was associated with a higher proportion of patients receiving investigations and a lower risk of developing certain complications such as infections and readmissions. Overall, the evidence supports the use of care pathways in acute stroke but not stroke rehabilitation. Future developments, including electronic care pathways, patient pathways, and pre-hospital care pathways for hyperacute stroke, will be discussed.     

One-year follow-up of patients with first-episode schizophrenia (comparison between remitters and non-remitters)

Patients admitted to hospital after being diagnosed with first-episode schizophrenia were comprehensively assessed prior to acute treatment (on admission), at the end of the acute treatment (at discharge), and at follow-up after 1 year. The psychopathology was evaluated using the Positive and Negative Syndrome Scale (PANSS). 93 patients were reassessed after 1 year. 73/93 (78%) of the patients fulfilled the criteria for remission. No statistically significant differences in the total PANSS or subscales scores were found between remitters and non-remitters before or after the first episode treatment. However, non-remitters had a significantly higher total PANSS score after 1 year than remitters. There was no significant difference in mean psychopathology on admission or at discharge, with the exception of items conceptual disorganization, difficulty in abstract thinking, and lack of judgment and insight between remitters and non-remitters. However, significantly higher mean values were found for all items after 1 year in non-remitters than remitters. On admission the occurrence of positive, negative and general symptoms was balanced; at discharge and after 1 year negative and general symptoms were the most frequently observed. At the 1-year follow-up the impairment of insight and judgment is one of the most frequent symptoms in both remitters (10%) and non-remitters (70%).     

Cefazolin plus ceftazidime versus imipenem/cilastatin monotherapy for treatment of CAPD peritonitis--a randomized controlled trial.

BACKGROUND: Peritonitis is a serious complication of peritoneal dialysis (PD). We studied the efficacy of imipenem/cilastatin monotherapy in the treatment of PD-related peritonitis. METHODS: We performed an open-label, randomized control study comparing imipenem/cilastatin monotherapy (treatment group) versus cefazolin plus ceftazidime (control group) in the treatment of PD peritonitis. The result was further compared to a historic group treated with cefazolin plus netilmycin. Outcome measures were primary response rate at day 10 and complete cure rate. RESULTS: We enrolled 51 patients in the treatment group, 51 in the control group, and identified 96 in the historic group. The primary response rate to the assigned antibiotics was 49.0%, 51.0%, and 49.0% for the treatment, control, and historic groups, respectively (p = 0.97). The primary response rate allowing for change in antibiotic was 82.4%, 90.2%, and 82.3%, respectively, for the three groups (p = 0.41). The complete cure rate was 72.5%, 80.4%, and 82.3%, respectively (p = 0.60). Tenckhoff catheter removal was needed in 6 cases in the treatment group, 6 cases in the control group, and 13 cases in the historic group (p = 0.90). CONCLUSIONS: We concluded that monotherapy of imipenem/cilastatin has similar efficacy compared to the two standard regimens of cefazolin plus ceftazidime or netilmycin in the treatment of PD peritonitis.     

123I-MIBG myocardial scintigraphy as a noninvasive screen for the diagnosis of coronary artery spasm

Background  It has been suggested that the sympathetic nervous system might play an important role in the development of coronary artery spasm. However, no cardiac imaging modality has been able to demonstrate abnormal sympathetic innervation in patients with coronary artery spasm. The purpose of this study was to assess the presence and location of abnormal sympathetic innervation using iodine 123-metaiodobenzylguanidine (¹²³I-MIBG) single photon emission computed tomography (SPECT) and to evaluate the clinical efficacy of ¹²³I-MIBG SPECT as a noninvasive screening test in patients with coronary artery spasm. Methods and Results  Coronary arteriography and a provocative test with intravenous administration of ergonovine maleate were performed in 26 patients (20 men, 6 women, mean age 48.2±12.0 years, range 20 to 67 years) who were suspected of having a coronary artery spasm. The subjects were divided into 2 groups: group 1 (n=18) comprised subjects with negative provocative provocative test result, and group 2 (n=8) comprised subjects with negative provocative test results. Ten healthy subjects served as controls. No abnormal MIBG uptake was observed in the control subjects. Abnormal sympathetic nervous innervation using ¹²³I-MIBG SPECT was observed either as a reduced uptake or a defective pattern in the perfused areas in 13 of the 18 regions supplied by vessels of ergonovine-induced vasospasm. Normal sympathetic innervation, as evidenced by normal ¹²³I-MIBG uptake, was noted in all of the 60 segments of normal vessel territories. Reduced uptake of ¹²³I-MIBG was not detected in the perfused areas of 5 vasospasm-induced vessels (perfusion territory of left anterior descending coronary artery [LAD] and the right coronary artery [RCA] in 2 and 3 patients, respectively). The sensitivity and specificity of ¹²³I-MIBG for detection of coronary artery spasm were 72.2% (95% confidence interval, [CI] 55% to 89%) and 100%, respectively. The positive predictive and negative predictive values were 100% and 92.3% (95% CI 91% to 93%), respectively. Conclusion   ¹²³I-MIBG SPECT is a feasible method to evaluate noninvasively and localize the territories of coronary arteries with spasm. Invasive diagnostic coronary arteriography with ergonovine provocation test may be unnecessary for diagnosis of coronary artery spasm in patients with typical resting pain, negative exercise test or normal thallium perfusion scan results, but showing abnormalities in ¹²³I-MIBG SPECT. Presented in part at the European Association of Nuclear Medicine Congress, September 1996, Copenhagen, Denmark.     

A novel bioassay approach: Direct application of the toxi-chromotest and the SOS chromotest to sediments

Routine testing of sediments or suspended sediments for toxicant or genotoxicants by the bioassay route often involves time-consuming and expensive organic extraction procedures. In most instances these extraction procedures are more time-consuming and costly than the bioassays that will be used on these extracts. A direct sediment test procedure (DSTP) was developed to alleviate the problem and thus returning bioassays to one of their original roles, i.e., short, quick, screening tests to identify priority samples for more intensive chemical analysis. The DSTP was developed in conjunction with the Toxi-Chromotest and SOS Chromotest kits. The SOS Chromotest can be used with or without S9. Our results presented in this paper indicate the sensitivity of DSTP and cost effectiveness compared to some commonly used sediment extraction procedures.     

Alpha-adrenoceptors in dog mesenteric vessels--subcellular distribution and number of [3H]prazosin and [3H]rauwolscine binding sites.

Binding of the alpha-adrenergic antagonists [3H]prazosin and [3H]rauwolscine to well-characterized subcellular membrane fractions isolated from dog mesenteric arteries and veins was studied. Binding of both ligands was saturable with Kd values of 0.5 +/- 0.1 nM for [3H]prazosin and 5.85 +/- 0.85 nM for [3H]rauwolscine in arteries, and 0.87 +/- 0.4 nM for [3H]prazosin and 6.6 +/- 1.5 nM for [3H]rauwolscine in veins. In veins, the maximum number of binding sites for [3H]rauwolscine was higher than that for [3H]prazosin, whereas in arteries the maximum number of binding sites for each ligand was similar. In microsomes from dog aorta, the maximum number of bindings sites for [3H]prazosin was higher than that for [3H]rauwolscine. Neuronal membrane contamination in these studies was minimized by dissection procedures and evaluated by the comparison of [3H]saxitoxin binding in various preparations. Only mesenteric veins responded functionally to agonists acting on alpha 2 adrenoceptors. This study thus identified two distinct populations of [3H]prazosin and [3H]rauwolscine binding sites in the plasma membranes of dog mesenteric vessels and suggests that a much higher density of alpha 2-compared to alpha 1-adrenoceptor binding sites is required for a contractile response.