The nucleus incertus is located caudal to the dorsal raphe and medial to the dorsal tegmentum. It is composed of a pars compacta and a pars dissipata and contains acetylcholinesterase, glutamic acid decarboxylase, and cholecystokinin-positive somata. In the present study, anterograde tracer injections in the nucleus incertus resulted in terminal-like labeling in the perirhinal cortex and the dorsal endopyriform nucleus, the hippocampus, the medial septum diagonal band complex, lateral and triangular septum medial amygdala, the intralaminar thalamic nuclei, and the lateral habenula. The hypothalamus contained dense plexuses of fibers in the medial forebrain bundle that spread in nearly all nuclei. Labeling in the suprachiasmatic nucleus filled specifically the ventral half. In the midbrain, labeled fibers were observed in the interpeduncular nuclei, ventral tegmental area, periaqueductal gray, superior colliculus, pericentral inferior colliculus, pretectal area, the raphe nuclei, and the nucleus reticularis pontis oralis. Retrograde tracer injections were made in areas reached by anterogradely labeled fibers including the medial prefrontal cortex, hippocampus, amygdala, habenula, nucleus reuniens, superior colliculus, periaqueductal gray, and interpeduncular nuclei. All these injections gave rise to retrograde labeling in the nucleus incertus but not in the dorsal tegmental nucleus. These data led us to conclude that there is a system of ascending projections arising from the nucleus incertus to the median raphe, mammillary complex, hypothalamus, lateral habenula, nucleus reuniens, amygdala, entorhinal cortex, medial septum, and hippocampus. Many of the targets of the nucleus incertus were involved in arousal mechanisms including the synchronization and desynchronization of the theta rhythm.

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The medial sural artery supplies the medial gastrocnemius muscle and sends perforating branches to the skin. The possible use of these musculocutaneous perforators as the source of a perforator-based free flap was investigated in cadavers. Ten legs were dissected, and the topography of significant perforating musculocutaneous vessels on both the medial and the lateral gastrocnemius muscles was recorded. A mean of 2.2 perforators (range, 1 to 4) was noted over the medial gastrocnemius muscle, whereas in only 20 percent of the specimens was a perforator of moderate size noted over the lateral gastrocnemius muscle. The perforating vessels from the medial sural artery clustered about 9 to 18 cm from the popliteal crease. When two perforators were present (the most frequent case), the perforators were located at a mean of 11.8 cm (range, 8.5 to 15 cm) and 17 cm (range, 15 to 19 cm) from the popliteal crease. A series of six successful clinical cases is reported, including five free flaps and one pedicled flap for ipsilateral lower-leg and foot reconstruction. The dissection is somewhat tedious, but the vascular pedicle can be considerably long and of suitable caliber. Donor-site morbidity was minimal because the muscle was not included in the flap. Although the present series is short, it seems that the medial sural artery perforator flap can be a useful flap for free and pedicled transfer in lower-limb reconstruction.

BACKGROUND AND PURPOSE Exposure to an ototoxic level of an aminoglycoside can result in hearing loss. In this we study investigated the otoprotective efficacy of dexamethasone (DXM), melatonin (MLT) and tacrolimus (TCR) in gentamicin (GM)-treated animals and cultures. EXPERIMENTAL APPROACH Wistar rats were divided into controls (treated with saline); exposed to GM only (GM); and three GM-exposed groups treated with either DXM, MLT or TCR. Auditory function and cochlear surface preparations were studied. In vitro studies of oxidative stress, pro-inflammatory cytokine mRNA levels, the MAPK pathway and caspase-3 activation were performed in organ of Corti explants from 3-day-old rats. KEY RESULTS DXM, MLT and TCR decreased levels of reactive oxygen species in GM-exposed explants. The mRNA levels of TNF-α, IL-1β and TNF-receptor type 1 were significantly reduced in GM + DXM and GM + MLT groups. Phospho-p38 MAPK levels decreased in GM + MLT and GM + TCR groups, while JNK phosphorylation was reduced in GM + DXM and GM + MLT groups. Caspase-3 activation decreased in GM + DXM, GM + MLT and GM + TCR groups. These results were consistent with in vivo results. Local treatment of GM-exposed rat cochleae with either DXM, MLT or TCR preserved auditory function and prevented auditory hair cell loss. CONCLUSIONS AND IMPLICATIONS In organ of Corti explants, GM increased oxidative stress and initiated an inflammatory response that led to the activation of MAPKs and apoptosis of hair cells. The three compounds tested demonstrated otoprotective properties that could be beneficial in the treatment of ototoxicity-induced hearing loss.

The rectosacral fascia divides the retrorectal space into inferior and superior portions. This must be differentiated from Waldeyer's description of the fascia lying in the inferior limit of the retrorectal space, formed by the fusion of the rectal visceral and parietal fascias.