Kv4.2 and KChIP2 transcription in individual cardiomyocytes from the rat left ventricular free wall

Biophysical and genetic evidence suggests that Kv4-KChIP2 heteromeric ion channels are the molecular correlate of the dominating fast component of the cardiac transient outward K+ current (Itof). Since Itof is one of the essential currents contributing to the shape of the cardiac action potential in the rat, ferret, dog, and human heart, an important implication of this concept is that all ventricular cardiac myocytes from these species express members of the Kv4 and the KChIP2 gene family. To test this prediction, we developed a modified protocol for the collection and subsequent multiplex single-cell RT-PCR amplification of RNA from individual cardiomyocytes isolated from defined regions of the rat left ventricle. All cardiomyocytes investigated (n=61) were positive for alpha-MHC and Kv4.2 expression. KChIP2 mRNA could also be detected in the vast majority (approximately 87%) of cardiomyocytes. Nearly all of these myocytes co-expressed all three cardiac splice variants of KChIP2. In a small but distinct fraction of myocytes (13%), however, we failed to detect KChIP2 mRNA. The detection thresholds were similar for all target genes and approached a sensitivity of a few molecules of RNA per cell. Our findings support the hypothesis that Itof is mediated by Kv4-KChIP2 heteromeric ion channels in the great majority of cardiac myocytes. A small subpopulation of cardiomyocytes, however, appears to express KChIP2 mRNA at insignificant levels and may therefore use other accessory subunits to generate Itof.     

The threat of misdiagnosis of primary osteosarcoma over the age of 60: a series of seven cases and review of the literature

Background

Osteosarcoma is the most common, non-haematopoietic, primary malignant bone tumour with an incidence of 0.3–0.5 per 100,000. There is some discrepancy in literature concerning the peaks of incidence of osteosarcoma. Some describe only one peak which arises in adolescence, whilst others report a bimodal age distribution with a second peak over the age of 60. In this retrospective study, we evaluated osteosarcoma patients over age 60 treated at our department and reviewed previous studies from the literature.

Patients and methods

Sixty-four patients (40 male, 24 female) with a mean age of 29 years (from 7 to 82) were treated for primary osteosarcomas. At the time of diagnosis, seven patients (two male and five female) were over 60 years of age with a mean follow-up of 46 months after definite diagnosis.

Results

Three out of seven osteosarcomas were primarily radiologically or histologically misdiagnosed, but only one was mistreated with intramedullary nailing at a trauma centre. At last follow-up, two patients had died from the disease, three were alive with disease, and two had no evidence of osteosarcoma.

Conclusions

We did not find an increased incidence of primary osteosarcoma in the elderly; yet, older patients had a higher rate of misdiagnosis due to untypical radiological findings in combination with longer times from the onset of first symptoms to definite diagnosis. In cases of pathological fracture, it is essential to assess whether it is caused by mechanical stress or a primary or secondary tumour before leading into mistreatment, especially in older patients.     

Low serum HDL‐cholesterol levels are associated with long symptom duration in patients with major depressive disorder

Aims: The purpose of the present study was to examine whether the association between depression and the serum high‐density lipoprotein cholesterol (HDL‐C) is modified by symptom duration. Methods: Depressed patients (n = 88) and an age‐ and sex‐matched group of healthy general population controls (n = 88) underwent a Structured Clinical Interview for DSM‐IV (SCID), and depressed participants reported the duration of their symptoms. The serum levels of total cholesterol (TC), HDL‐C, low‐density lipoprotein cholesterol (LDL‐C), triglycerides (TG) and non‐HDL, and the ratios of LDL‐C/HDL and TC/HDL‐C were assessed. Results: Major depressive disorder (MDD) subjects with a long symptom duration (≥3 years) had lower levels of HDL‐C compared with healthy controls or MDD subjects with a symptom duration <3 years. The likelihood for long symptom duration doubled for each 0.5‐mmol/L decrease in HDL‐C levels in regression models adjusted for age, gender, marital status, overweight, symptom severity, alcohol consumption, smoking, physical exercise, medication use, and non‐HDL‐C (P < 0.05). Conclusions: These findings suggest that a low serum HDL‐C level, a risk factor for coronary heart disease, is specifically associated with long‐term depressive symptomatology.     

Depressive symptoms during rehabilitation period predict poor outcome of lumbar spinal stenosis surgery: A two-year perspective

Background  

Previous research has shown an association between preoperative depressive symptoms and a poorer surgery outcome in lumbar spinal stenosis (LSS). It is not known whether depressive symptoms throughout the recovery period are relevant to the outcome of surgery in LSS. In this prospective clinical study the predictive value of preoperative and postoperative depressive symptoms with respect to the surgery outcome is reported.     

Diminished Kv4.2/3 but not KChIP2 levels reduce the cardiac transient outward K+ current in spontaneously hypertensive rats

OBJECTIVE: A reduction of the Ca(2+)-independent transient outward potassium current (I(to)) in epicardial but not in endocardial myocytes of the left ventricle has been observed in cardiac hypertrophy and is thought to contribute to the electrical vulnerability associated with this pathology. METHODS: In the present study we investigated the molecular mechanisms underlying regional alterations in I(to) in hypertrophied hearts of spontaneously hypertensive rats (SHR) using the whole-cell patch-clamp technique, quantitative RT-PCR and heterologous expression of underlying ion channel subunits. RESULTS: I(to) was significantly smaller in epicardial myocytes of SHR than in Wistar-Kyoto (WKY) controls (11.1+/-0.9 pA/pF, n=20 vs. 16.8+/-1.7 pA/pF, n=20, p<0.01), but not different in endocardial myocytes from both groups. Quantitative RT-PCR analysis of the genes encoding I(to) revealed significantly lower levels of Kv4.2 and Kv4.3 mRNA in the epicardial region of SHR rats compared to WKY rats. In contrast, mRNA expression levels of all three splice variants of the beta-subunit KChIP2 were significantly higher in both endo- and epicardial myocytes from SHR than from WKY rats. In parallel, inactivation of I(to), which is negatively modulated by KChIP2, was slowed down in SHR while recovery from inactivation remained unchanged. Heterologous co-expression of increasing amounts of KChIP2b together with a fixed amount of Kv4.2 in Xenopus laevis oocytes revealed a hyperbolic relation of recovery from inactivation and inactivation time constant, demonstrating that KChIP2 preferentially affects inactivation, if its expression level is high. CONCLUSION: These results suggest that downregulation of I(to) in the left ventricle of SHR is mediated by a reduced expression of Kv4.2 and Kv4.3 (but not of KChIP2), whereas the slower inactivation of I(to) can be explained by increased expression levels of KChIP2 in SHR.     

Serum anti-inflammatory markers in general population subjects with elevated depressive symptoms

Anti-inflammatory substances have previously been suggested to show compensatory elevations in depressed individuals with pronounced inflammatory changes. In order to further clarify these observations, we examined depression-related alterations in the serum levels of anti-inflammatory markers interleukin (IL)-1 receptor antagonist (RA) and IL-10 and the pro-inflammatory marker IL-6 in 416 general population participants. Depression was evaluated with the Beck Depression Inventory (BDI). Participants with elevated depressive symptoms (BDI > 14, n = 44) had increased levels of IL-1 RA and IL-6. No changes were observed in their IL-10 levels. In multivariate modeling with adjustments for age, gender, obesity, regular smoking, alcohol use, metabolic syndrome, physical exercise, sleep disturbance, and the use of non-steroidal anti-inflammatory drugs, a high level of IL-1 RA was associated with an increased likelihood of belonging to the group with elevated depressive symptoms (OR for each 1 SD increase in the serum level of IL-1 RA: 2.17, 95% CI 1.35–3.48, p = 0.001). The significance of IL-6 alterations did not persist in the same model. The pronounced secretion of anti-inflammatory marker IL-1 RA may reflect the presence of compensatory mechanisms during a depression-related inflammatory state.     

Intact surface of bioactive glass S53P4 is resistant to osteoclastic activity

Bioactive glass reacts with body fluids and is gradually dissolved in tissues and in cell cultures. We investigated whether osteoclasts contribute to this process, by culturing newborn rat bone-marrow cells containing osteoclasts on polished bioactive glass plates (glass S53P4). The cultures were inspected at days 1-5 and stained for alkaline phosphatase (ALP) to demonstrate osteoblasts and for tartrate resistant acid phosphatase (TRAP) to visualize osteoclasts. Nonosteoclastic cells proliferated several-fold both on bioactive glass and on plastic, whereas osteoclasts and their precursors matured into multicellular giant cells and degenerated. Most cells on bioactive glass became ALP-positive, whereas on plastic the majority of cells remained ALP-negative. Osteoclasts survived on bioactive glass for 4-5 days, whereas on plastic they degenerated and disappeared after 3 days. Condensed nuclei indicating apoptosis were detected both in degenerating osteoclasts and osteoblasts. The surface of the bioactive glass reacted rapidly forming rounded pits, erosions, and cracks within 24 h in areas occupied by osteoblasts. Light microscopy and scanning electron micrographs demonstrated, however, a smooth surface below the cytoplasm of osteoclasts. This indicates that when applied on an intact bioactive glass surface, osteoclasts were unable to dissolve the glass material within this culture period.     

Medicinal leeches for the treatment of venous congestion and hematoma after plastic reconstructive surgery

Background: Leeches were used for medical purposes as long as 2 000 years ago in ancient Egypt. In recent years the use of medicinal leeches became rather popular again, e. g. to improve blood circulation in ischemic tissue after reconstructive plastic surgery. Patients and Methods: In a single center, retrospective study 23 consecutive cases were analyzed in which medicinal leeches had been used therapeutically after plastic reconstructive surgery. All cases were categorized regarding the indication for leech therapy, the onset, the duration, the number of leeches and the number of sessions. Results: Among the group of patients there were 7 female and 16 male patients with a mean age of 73 ± 14 years (48–94 years) altogether. The main indications were venous congestion (12/23; 52 %) and hematoma (9/23; 39 %). Two cases were diagnosed with a necrosis of the tip of the flap and therefore received leech therapy (2/23; 9 %). The average number of leeches was 2.6 leeches/session, the number of sessions was 1.7 ± 0.8. 20/23 patients (87 %) showed a restitutio ad integrum after leech therapy, in 3/23 patients (13 %) a necrosis of the tip of the flap could not be prevented. A clinical improvement was noticed after an average of 1.1 ± 0.3 days. Conclusions: The early application of medicinal leeches can improve local hemodynamic conditions. Leech therapy is a simple and effective method; the cost efficiency of the treatment is high.     

Clinical and molecular characterization of a near fatal case of human babesiosis in Austria

A previously healthy febrile patient with travel history to Nicaragua showed rapid clinical deterioration with hemodynamic shock and anuria. Diagnosis of severe malaria was established based on intra-erythrocytic parasites and antimalarial treatment was initiated. However, upon reevaluation Babesia microti infection was suspected and molecular characterization by polymerase chain reaction and sequence analysis was performed.