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At least 1,063 records · Page 59Linked to original sources
PubMed1980

Spinal melanotic clear-cell sarcoma: a light and electron microscopic study.

We report a melanotic spindle-cell tumor that arose from a thoracic spinal nerve root and metastasized to both lungs. The bulk of the tumor consisted of glycogen-rich clear cells and bore a striking resemblance on light and electron microscopy to at least one variant of the clear-cell sarcoma of tendons and aponeuroses. The presence of schwannoma-like areas noted in the primary tumor on light microscopy and the formation of a highly developed basal lamina noted on ultrastructural examination suggest that the tumor may be a partially dedifferentiated malignant melanotic schwannoma. This tumor is discussed in the context of a simple histogenetic classification of melanotic tumors.

Adolescent↗
PubMed1981

Diabetic thoracoabdominal neuropathy: clinical and electrodiagnostic features.

Five diabetic patients developed upper back or abdominal pain associated with substantial weight loss in three. Electrophysiological evidence of associated thoracoabdominal somatic neuropathy was found in all cases. Signs of a generalized neuropathy were present in two patients, and four had asymmetrical proximal leg weakness. At least two have improved spontaneously. The syndrome is closely related to diabetic amyotrophy; it is probably more common than is recognized.

Abdominal Muscles↗
PubMed2002

Danger of damaging the medial branches of the posterior rami of spinal nerves during a dorsomedian approach to the spine.

Postoperative atrophy of the deep back muscles may be caused by denervation during a dorsomedian approach to the thoracolumbar spine; ensuing instability of the spine with poor clinical results, perhaps due to such muscle loss, has been observed in 11.7% of cases (Sihvonen et al., 1993, Spine 18:575--581). More specifically, this complication may be caused by damaging the medial branches of the posterior rami of the spinal nerves during lateral retraction of the muscles. To investigate the anatomic topography of the medial branches of the posterior rami of the spinal nerves, 18 carbol-formol-fixed specimens were dissected using an operation microscope; also, 3 fresh cadavers were cut in horizontal and vertical planes with a rotary cryotome to confirm the anatomic topography observed in the fixed specimens. In the thoracolumbar spine the medial branch of the posterior ramus of the spinal nerve is subject to ligamentous fixation by the strong fibers of the mammillo-accessory ligament, which extends between the mammillary process and accessory process infero lateral to the superior articular process. When the dorsomedian approach to the thoracolumbar spine is enlarged laterally to the articular processes by retracting the paraspinous muscles, the medial branches of the posterior rami of the spinal nerves are endangered. This may cause postoperative pain as well as dynamic instability beyond the corresponding segments. The results of our anatomic study suggest that the posterior surgical midline approach to the thoracolumbar spine should not be enlarged laterally to the articular processes to prevent injury to the medial branches of the posterior rami of the spinal nerves.

Dissection↗
PubMed1975

Five fluorocarbons for administration of aerosol bronchodilators.

The exposure of the upper respiratory tract to aerosol propellants produces apnea, bradycardia, and biphasic fall and rise in aortic blood pressure in anesthetized dogs. This response represents the irritation of sensory receptors in the nasal and nasopharyngeal mucosa and is not elicited with aerosol propellants administered via a tracheal cannula bypassing the upper respiratory tract. When this is done, a different reflex is elicited, consisting of tachycardia that is mediated by the thoracic sympathetic nerves. There is either bronchodilation or bronchoconstriction depending on the type of propellant. The three propellants (11, 12, and 114) widely used in aerosols, when inspired in large doses, elicit both bradycardia and tachycardia and induce bronchoconstriction or bronchodilation. Two additional propellants (115 and C318), which are not ordinarily used to dispense bronchodilator drugs, do not elicit any change in heart rate and produce only bronchodilation. It is suggested that these two propellants merit further investigation and may replace the three widely used ones if these prove the use and abuse of aerosols.

Aerosol Propellants↗
PubMed1992

Free flap transfer of the cutaneous maximus muscle in the rat: comparison to the latissimus dorsi muscle flap.

A new rat model of free muscle flap transfer is presented. Microvascular transplantation of the cutaneous maximus muscle flap is performed at the groin site, with anastomosis of the axillary vessels to the appropriate femoral vessels. This muscle flap has many useful attributes for experimental manipulation. It has a high success rate following transplantation, the anatomy is consistent, the dissection is straightforward, the length of pedicle is relatively long (10 mm), the vessels for repair are of sufficient size (1.0-1.35 mm diameter), and the microsurgical procedure can be performed in a relatively short period. The donor site deficit causes minimal impairment to animal mobility, and no evidence of limb ischemia is noted after ligation of the axillary vessels. The cutaneous area adjacent to the muscle is perfused by muscular perforators supplied by the flap pedicle; thus a skin island may be used to monitor the flap or to create a composite myocutaneous transfer. The cutaneous maximus muscle has mixed muscle types and anatomic dimensions similar to those of the latissimus dorsi muscle, and it provides ample tissue for pharmacological and biochemical studies, yet it presents easier dissection and microanastomoses than the latissimus flap, with more potential for versatility in application. The advantages of this muscle flap make it a very useful experimental model for flap transfer research.

Animals↗
PubMed1994

Pectoralis major muscle free flap in rat model.

The rat pectoralis muscle can serve as a vascularized, innervated muscle flap model. The muscle, consisting of superficialis and profundus portions, is supplied by separate neurovascular systems. The vessels to pectoralis profundus (averaging 0.3 mm in diameter) can be taken in continuity with the axillary vessels (averaging 11 mm in diameter), which are used for transplantation. The profundus portion of muscle weighed an average of 1.8 g, and the average pedicle length was 0.9 cm. Nine of 11 transplanted muscles were viable, with intact circulation at 72 hours. An example of muscle transplantation for tissue defect coverage was attempted. The pectoralis profundus transplant was technically reliable, and the muscle bulk and contour could allow biochemical and functional studies.

Abdominal Muscles↗
PubMed1989

Central projections of a homoeotic regenerate, antennapedia, in a stick insect, Carausius morosus (Phasmida).

Homoeotic appendages provide a system for the analysis of neural path-finding in which the appendage is mismatched with its segmented ganglion. Central projections of sensory neurons from homoeotic antennapedia regenerates induced by antennal amputation in the stick insect, Carausius morosus, are described. The majority of afferent axons project to the olfactory lobe as in the normal antennal nerve, but they do not give rise to compact glomeruli. Nor does the form of the projection resemble that of leg sensory nerves in thoracic ganglia. The projection of antennapedia regenerate neurons in Carausius resembles the antennapedia mutant of Drosophila except that some primary afferents bypass the olfactory lobe and take several courses through the brain, sometimes reaching distant contralateral areas. It appears that these wandering fibers, having bypassed the olfactory lobe, tend to follow established tracts and to arborize or to deviate at circumscribed synaptic areas. The behavioral evidence for sensory input from antennapedia regenerates is equivocal.

Animals↗
PubMed1995

Differential delay of reinnervating axons alters specificity in the rat serratus anterior muscle.

Previous studies have shown remarkable rostrocaudal selectivity by regenerating motoneurons to the rat serratus anterior (SA) muscle after freezing, crushing, or sectioning the long thoracic (LT) nerve. The LT nerve contains motoneurons from both the sixth and seventh cervical spinal nerves (C6 and C7), with C6 motoneurons as the major source of innervation throughout the muscle, and with C7 motoneurons innervating a larger percentage of muscle fibers caudally than rostrally. To determine if synaptic competition can play a role in neuromuscular topography, both the LT nerve and the branch carrying C6 (rostral) motoneurons to the LT nerve were crushed in newborn rats. This approach provides a temporal advantage to regenerating C7 (caudal) motoneurons. After an initial period during which C7 motoneurons reinnervated a larger proportion of muscle fibers than normal in all SA muscle sectors, C6 motoneurons regained their original proportion of rostral muscle fibers. Caudally, however, C7 motoneurons maintained an expanded territory. With this two-site crush method, the number of C6 motoneurons that reinnervate the SA muscle was significantly decreased from normal, whereas the number of C7 motoneurons remained the same. It is concluded that when C7 motoneurons are given a temporal advantage, synaptic specificity can be altered transiently in rostral muscle sectors and permanently in caudal sectors, and this is correlated with a disproportionate loss of C6 motoneurons. Moreover, this may be an important model for studies of synaptic competition, where terminals destined to be eliminated can be identified beforehand.

Analysis of Variance↗
PubMed1999

Dynein-dynactin function and sensory axon growth during Drosophila metamorphosis: A role for retrograde motors.

Mutations in the genes for components of the dynein-dynactin complex disrupt axon path finding and synaptogenesis during metamorphosis in the Drosophila central nervous system. In order to better understand the functions of this retrograde motor in nervous system assembly, we analyzed the path finding and arborization of sensory axons during metamorphosis in wild-type and mutant backgrounds. In wild-type specimens the sensory axons first reach the CNS 6-12 h after puparium formation and elaborate their terminal arborizations over the next 48 h. In Glued1 and Cytoplasmic dynein light chain mutants, proprioceptive and tactile axons arrive at the CNS on time but exhibit defects in terminal arborizations that increase in severity up to 48 h after puparium formation. The results show that axon growth occurs on schedule in these mutants but the final process of terminal branching, synaptogenesis, and stabilization of these sensory axons requires the dynein-dynactin complex. Since this complex functions as a retrograde motor, we suggest that a retrograde signal needs to be transported to the nucleus for the proper termination of some sensory neurons.

Animals↗
PubMed2000

Sacral neural crest cell migration to the gut is dependent upon the migratory environment and not cell-autonomous migratory properties.

Avian neural crest cells from the vagal (somite level 1-7) and the sacral (somite level 28 and posterior) axial levels migrate into the gut and differentiate into the neurons and glial cells of the enteric nervous system. Neural crest cells that emigrate from the cervical and thoracic levels stop short of the dorsal mesentery and do not enter the gut. In this study we tested the hypothesis that neural crest cells derived from the sacral level have cell-autonomous migratory properties that allow them to reach and invade the gut mesenchyme. We heterotopically grafted neural crest cells from the sacral axial level to the thoracic level and vice versa and observed that the neural crest cells behaved according to their new position, rather than their site of origin. Our results show that the environment at the sacral level is sufficient to allow neural crest cells from other axial levels to enter the mesentery and gut mesenchyme. Our study further suggests that at least two environmental conditions at the sacral level enhance ventral migration. First, sacral neural crest cells take a ventral rather than a medial-to-lateral path through the somites and consequently arrive near the gut mesenchyme many hours earlier than their counterparts at the thoracic level. Our experimental evidence reveals only a narrow window of opportunity to invade the mesenchyme of the mesentery and the gut, so that earlier arrival assures the sacral neural crest of gaining access to the gut. Second, the gut endoderm is more dorsally situated at the sacral level than at the thoracic level. Thus, sacral neural crest cells take a more direct path to the gut than the thoracic neural crest, and also their target is closer to the site from which they initiate migration. In addition, there appears to be a barrier to migration at the thoracic level that prevents neural crest cells at that axial level from migrating ventral to the dorsal aorta and into the mesentery, which is the portal to the gut.

Animals↗