Combined irrigation provides sufficient reduction in temperature changes during drilling, and it may be more beneficial in deeper site osteotomies. Further studies to optimize the effects of a combined irrigation are needed.

Respecting the mechanical properties of the Schneiderian membrane may help reducing the complication rates and thus patient morbidity in minimally invasive maxillary sinus floor elevation.

This fully standardized bone model provides optimized comparability for the evaluation of bone osteotomies and resulting temperature changes. As regards the efficiency of the various irrigation methods, it could be demonstrated that internal and combined irrigation appears to be more beneficial than external irrigation.

JC. Atrophy, but not necrosis, in rabbit skeletal muscle denervated for periods up to one year. Am J Physiol Cell Physiol 292: C440 -C451, 2007; doi:10.1152/ajpcell.00085.2006.-Our understanding of the effects of long-term denervation on skeletal muscle is heavily influenced by an extensive literature based on the rat. We have studied physiological and morphological changes in an alternative model, the rabbit. In adult rabbits, tibialis anterior muscles were denervated unilaterally by selective section of motor branches of the common peroneal nerve and examined after 10, 36, or 51 wk. Denervation reduced muscle mass and cross-sectional area by 50 -60% and tetanic force by 75%, with no apparent reduction in specific force (force per cross-sectional area of muscle fibers). The loss of mass was associated with atrophy of fast fibers and an increase in fibrous and adipose connective tissue; the diameter of slow fibers was preserved. Within fibers, electron microscopy revealed signs of ultrastructural disorganization of sarcomeres and tubular systems. This, rather than the observed transformation of fiber type from IIx to IIa, was probably responsible for the slow contractile speed of the muscles. The muscle groups denervated for 10, 36, or 51 wk showed no significant differences. At no stage was there any evidence of necrosis or regeneration, and the total number of fibers remained constant. These changes are in marked contrast to the necrotic degeneration and progressive decline in mass and force that have previously been found in long-term denervated rat muscles. The rabbit may be a better choice for a model of the effects of denervation in humans, at least up to 1 yr after lesion.force; shortening velocity; electron microscopy; histochemistry MUCH OF OUR KNOWLEDGE of the effects of long-term denervation of mammalian skeletal muscle comes from experimental studies of total sciatic section in the rat (7,32,54). The mass of the affected muscles falls rapidly within 5-7 days of axotomy (11,18,22,25,55,57,58) and declines further to 30 -50% of control weight in succeeding weeks (1,5,11,14,23,41,60). After several months, muscle weight stabilizes at ϳ5-20% of control (1,13,45).Within the muscles, individual fibers show a reduction of ϳ70% in cross-sectional area (CSA) over a period of months (5,14,21,37), and over 90% (1,21,45) in the longer term. Initially, fast (type II) fibers are more susceptible to atrophy than slow (type I) fibers (5,7,32,38,48,54,59), but over more prolonged periods the fiber types atrophy to a similar extent (6, 54). Corresponding to this reduction in fiber CSA, there is a striking and progressive increase in interstitial collagen and fat (32). At the ultrastructural level, atrophic muscle fibers show evidence of disorganization, including loss or misalignment of sarcomeres, dissociation of the T system and sarcoplasmic reticulum (SR), and changes in the sarcomeric location of mitochondria (32, 51, 52).The major physiological correlate of these morphological changes is a loss of force-generati...

By improving spatial and anatomical specificity, localized spectroscopy can enhance the power and accuracy of the quantitative analysis of cellular metabolism and bioenergetics. Localized and nonlocalized dynamic 31P magnetic resonance spectroscopy using a surface coil was compared during aerobic exercise and recovery of human calf muscle. For localization, a short echo time single-voxel magnetic resonance spectroscopy sequence with adiabatic refocusing (semi-LASER) was applied, enabling the quantification of phosphocreatine, inorganic phosphate, and pH value in a single muscle (medial gastrocnemius) in single shots (TR = 6 s). All measurements were performed in a 7 T whole body scanner with a nonmagnetic ergometer. From a series of equal exercise bouts we conclude that: (a) with localization, measured phosphocreatine declines in exercise to a lower value (79 ± 7% cf. 53 ± 10%, P = 0.002), (b) phosphocreatine recovery shows shorter half time (t1/2 = 34 ± 7 s cf. t1/2 = 42 ± 7 s, nonsignificant) and initial postexercise phosphocreatine resynthesis rate is significantly higher (32 ± 5 mM/min cf. 17 ± 4 mM/min, P = 0.001) and (c) in contrast to nonlocalized 31P magnetic resonance spectroscopy, no splitting of the inorganic phosphate peak is observed during exercise or recovery, just an increase in line width during exercise. This confirms the absence of contaminating signals originating from weaker-exercising muscle, while an observed inorganic phosphate line broadening most probably reflects variations across fibers in a single muscle. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.