High resolution structural evidence suggests the Sarcoplasmic Reticulum forms microdomains with acidic stores (lysosomes) in the heart

Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) stimulates calcium release from acidic stores such as lysosomes and is a highly potent calcium-mobilising second messenger. NAADP plays an important role in calcium signalling in the heart under basal conditions and following β-adrenergic stress. Nevertheless, the spatial interaction of acidic stores with other parts of the calcium signalling apparatus in cardiac myocytes is unknown. We present evidence that lysosomes are intimately associated with the sarcoplasmic reticulum (SR) in ventricular myocytes; a median separation of 20 nm in 2D electron microscopy and 3.3 nm in 3D electron tomography indicates a genuine signalling microdomain between these organelles. Fourier analysis of immunolabelled lysosomes suggests a sarcomeric pattern (dominant wavelength 1.80 μm). Furthermore, we show that lysosomes form close associations with mitochondria (median separation 6.2 nm in 3D studies) which may provide a basis for the recently-discovered role of NAADP in reperfusion-induced cell death. The trigger hypothesis for NAADP action proposes that calcium release from acidic stores subsequently acts to enhance calcium release from the SR. This work provides structural evidence in cardiac myocytes to indicate the formation of microdomains between acidic and SR calcium stores, supporting emerging interpretations of NAADP physiology and pharmacology in heart

Person-Specific Non-shared Environmental Influences in Intra-individual Variability : A Preliminary Case of Daily School Feelings in Monozygotic Twins

Most behavioural genetic studies focus on genetic and environmental influences on inter-individual phenotypic differences at the population level. The growing collection of intensive longitudinal data in social and behavioural science offers a unique opportunity to examine genetic and environmental influences on intra-individual phenotypic variability at the individual level. The current study introduces a novel idiographic approach and one novel method to investigate genetic and environmental influences on intra-individual variability by a simple empirical demonstration. Person-specific non-shared environmental influences on intra-individual variability of daily school feelings were estimated using time series data from twenty-one pairs of monozygotic twins (age = 10 years, 16 female pairs) over two consecutive weeks. Results showed substantial inter-individual heterogeneity in person-specific non-shared environmental influences. The current study represents a first step in investigating environmental influences on intra-individual variability with an idiographic approach, and provides implications for future behavioural genetic studies to examine developmental processes from a microscopic angle

Morphology of the proximal and middle phalanx of fingers with regard to the Ascension PyroCarbon PIP total joint

The Ascension PyroCarbon prosthesis has been used in proximal interphalangeal joint osteoarthritis. The dimensions of the intramedullary distal metadiaphyseal canal (isthmus) of the proximal phalanx and the base of the middle phalanx of cadaver fingers were investigated radiographically (n = 304) and macroscopically (n = 152). In up to 30% of the phalanges, the isthmus was smaller than the stem of the smallest proximal component size. The distal component head was always smaller than the middle phalanx base. Insertion and success of the Ascension PyroCarbon prosthesis is strongly dependent on bone morphology. A critical examination of the isthmus in radiographs is recommended in planning. If the isthmus is clearly smaller than the smallest proximal component, insertion of the prosthesis could be inadvisable. A clear mismatch between the distal component and the middle phalanx base should be avoided due to the potential risk for late subsidence and failure of the prosthesis

Surgical decompression of the superficial radial nerve

Objective. Open decompression of the superficial radial nerve is performed at the distal forearm in cases of circumscript entrapment. Broad-based entrapments can be treated by endoscopically assisted decompression. Indications. Entrapment of the nerve along its course between the brachioradialis and extensor carpi radialis longus muscles or tendons. Persistent neuropathic pain with Tinel's sign. Numbness distal to the entrapment in accordance to nerval innervation. Futile conservative treatment. Pathological electrophysiological findings. Contraindications. Endogeneous neuropathy, bleeding disorders, anticoagulation medication. Surgical technique. Longitudinal skin incision at the Tinel's sign at the forearm. The subcutaneous tissue is dissected until forearm fascia is detected. The fascia is opened cautiously under direct visualization and the superficial radial nerve is identified. In cases of broad-based entrapments, endoscopically assisted decompression can be performed. The dissector with attached optical device is introduced proximally and distally. Blunt mobilization using the dissector and preparation with the Metzenbaum scissors release the superficial radial nerve sufficiently. Postoperative management. Bandaging allowing immediate motion, removal of sutures after 14 days, avoidance of excessive use for 2 weeks. Results. Surgical decompression of the superficial radial nerve yields good to excellent results regarding pain reduction and sensory function

Proximal carpal row carpectomy

Resection of the proximal carpal row, termed proximal row carpectomy (PRC), is performed in order to treat pathologies of the proximal carpal row or radiocarpal joint between the scaphoid and scaphoid facet. It entails the articulation of the capitate and the lunate facet. Lunate necrosis, carpal collapse, joint infection with concomitant intercarpal ligament lesions. Severe cartilage lesions of the lunate facet and the capitate, wrist capsule laxity, rheumatoid arthritis, neuromuscular dysbalance of the wrist-covering soft tissue structures. Dorsal approach to the wrist, incision of the third and fourth extensor compartments, resection and coagulation of the dorsal interosseous nerve, usage of a ligament-sparing capsule incision, identification of the proximal carpal row and inspection of cartilage of the lunate facet and capitate, mobilization and excision of the lunate, scaphoid and triquetrum, articulation of lunate facet and capitate is controlled clinically and fluoroscopically, wound closure, application of plaster slabs. Immobilization of the wrist on plaster slabs for 2 weeks, removal of sutures after 14 days. PRC is a surgical procedure with few complications. Satisfactory range of motion and grip strength could be preserved without limiting function of the upper extremity. Postoperative osteoarthritis of capitate and lunate facet did not correlate with the good clinical outcome