Transposing the great trochanter bone flap pedicaled with the deep branch of the medial circumflex artery in repair of necrotic femoral head

The transposition of the greater trochanter bone flap pedicled with the deep branch of the medial circumflex artery was designed as a new therapeutic method for the treatment of early ischemic necrosis of the femoral head in adults. Bone flap was successfully used in 15 limbs of 13 patients. Applied anatomy, operative indications and procedure of the bone flap was introduced.     

Label-retaining cells are preferentially located in fornical epithelium: implications on conjunctival epithelial homeostasis

PURPOSE: To determine the cell kinetic properties of epithelial cells from various zones of the conjunctiva. METHODS: The morphology and cell kinetics of bulbar, fornical, and palpebral conjunctival epithelium were studied in neonatal and adult SENCAR mice. To examine the proliferative rate of the conjunctival epithelium, a single administration of tritiated thymidine (3H-TdR) was used to detect cells in "S" phase. Proliferative rates were also assessed by determining mitotic activity after an intraperitoneal injection of colchicine to arrest cells in mitosis. To detect slow-cycling cells, mice received 3H-TdR continuously for 1 week. After a 4-week chase, animals were sacrificed and eyes were surgically removed. All tissues were immediately fixed in formalin and processed for histology and autoradiography. RESULTS: Slow-cycling cells, detected as label-retaining cells (LRCs), were identified in bulbar, fornical, and palpebral epithelia, as well as in limbal epithelium. The greatest number of LRCs was found in fornical epithelium. In addition, we found a number of label-retaining goblet cells. This cell population was shown to incorporate 3H-TdR after a single pulse administration, and mitotic figures were seen in goblet cells after colchicine treatment, indicating that conjunctival goblet cells have proliferative capabilities. CONCLUSIONS: These findings are consistent with earlier in vitro data that the fornical epithelium may be a zone enriched in conjunctival epithelial stem cells. This has important implications in conjunctival epithelial development and is relevant in wound repair. Furthermore, the concept that goblet cells are slow-cycling cells with proliferative capabilities provides new insights into the area of conjunctival homeostasis.     

Tracer and electrical coupling of rat suprachiasmatic nucleus neurons

Whole-cell recording from single neurons of the suprachiasmatic nucleus with an electrode containing the tracer neurobiotin resulted in the staining of multiple neurons in 30% of the cases. Typically, one neuron was darkly stained with dendritic processes and an axon clearly visible while other neurons were lightly stained. The darkly-stained cells were identified as the recorded neuron and tracer-coupled to one to five lightly stained neurons. The resting membrane potential, input membrane conductance, membrane capacitance, the decay time constant and the maximum H-current amplitude of the recorded neurons with tracer-coupled cells were not significantly different from those of neurons not showing tracer coupling. Stimulation of the preoptic area activated an antidromic action potential or an all-or-none small slow inward current in some neurons when the synaptic transmission was blocked by a calcium-free/Mn2+ solution. The small slow inward current did not "collide" with an orthodromically activated action spike suggesting that the current represents the signal from an electrotonically-coupled neuron. In addition, the frequency of biphasic field currents from a neighbouring cell firing were increased by depolarization and decreased by hyperpolarization of the recorded cell. These data demonstrate a chemical and electrical low-resistance coupling of suprachiasmatic nucleus neurons, which could be important in synthesizing the suprachiasmatic nucleus circadian rhythm.     

Diffusion-weighted MR imaging of acute cerebral ischemia

Diffusion-weighted MR imaging has been used in studies on experimental animal models and on patients with acute cerebral ischemia. Compared with CT and conventional MR techniques, diffusion-weighted imaging can provide earlier and more precise detection of the location and the extent of an ischemic lesion during the critical first few hours after the onset of stroke. Quantitative apparent diffusion coefficient (ADC) mapping of the brain water can also be carried out by recording a series of diffusion-weighted images with different amplitudes of the displacement encoding gradients. ADC maps can provide important information about the extra- and intracellular water homeostasis. ADC reduction of the tissue water is one of the early signals of the pathophysiological cascade resulting from ischemic tissue injury. Diffusion MR imaging has become a valuable tool in stroke research. It may also prove a valuable tool in monitoring the efficiency of therapeutic effects in stroke patients. It is our intention to provide an overview of the recent development in this area with emphasis on the diffusion-weighted MR techniques, and to discuss the possible underlying biophysical mechanisms responsible for the contrast of diffusion-weighted imaging.     

Immobilized catalase in water purification systems

Plasmid screening of reference Pseudomonas pseudomallei strains isolated from patients and animals revealed cryptic plasmids with different molecular weights in 30 strains. Plasmids were investigated by restriction analysis and DNA-DNA hybridization. Cryptic plasmids were denoted as pPM1, pCM2, pCM3, and pCM4. The presence of plasmids in melioidosis agent permits their use for intraspecies typing of strains and for genetic studies.