Analysis of genetic diversity of Persea bombycina "Som" using RAPD-based molecular markers.

The utility of RAPD markers in assessing genetic diversity and phenetic relationships in Persea bombycina, a major tree species for golden silk (muga) production, was investigated using 48 genotypes from northeast India. Thirteen RAPD primer combinations generated 93 bands. On average, seven RAPD fragments were amplified per reaction. In a UPGMA phenetic dendrogram based on Jaccard's coefficient, the P. bombycina accessions showed a high level of genetic variation, as indicated by genetic similarity. The grouping in the phenogram was highly consistent, as indicated by high values of cophenetic correlation and high bootstrap values at the key nodes. The accessions were scattered on a plot derived from principal correspondence analysis. The study concluded that the high level of genetic diversity in the P. bombycina accessions may be attributed to the species' outcrossing nature. This study may be useful in identifying diverse genetic stocks of P. bombycina, which may then be conserved on a priority basis.

Treatment of aneurysmal bone cysts of the pelvis and sacrum.

BACKGROUND: Aneurysmal bone cysts are benign, non-neoplastic, highly vascular bone lesions. The purpose of this study was to describe the prevalence, the clinical presentation, and the recurrence rate of aneurysmal bone cysts of the pelvis and sacrum and to examine the diagnostic and therapeutic options and prognosis for patients with this condition. METHODS: Forty consecutive patients with an aneurysmal bone cyst of the pelvis and/or sacrum were treated from 1921 to 1996. Their medical records and radiographic and imaging studies were reviewed, and histological sections from the cysts were examined. Seventeen lesions were iliosacral, sixteen were acetabular, and seven were ischiopubic. Seven involved the hip joint, and two involved the sacroiliac joint. All twelve sacral lesions extended to more than one sacral segment and were associated with neurological signs and symptoms. Destructive acetabular lesions were associated with pathological fracture in five patients and with medial migration of the femoral head, hip subluxation, and hip dislocation in one patient each. The mean duration of follow-up was thirteen years (range, three to fifty-three years). RESULTS: Thirty-five patients who were initially treated for a primary lesion had surgical treatment (twenty-one had excision-curettage and fourteen had intralesional excision); two patients also had adjuvant radiation therapy. Of the thirty-five patients, five (14%) had a local recurrence noted less than eighteen months after the operation. Of five patients initially treated for a recurrent lesion, one had a local recurrence. At the latest follow-up examination, all forty patients were disease-free and twenty-eight (70%) were asymptomatic. There were two deep infections. CONCLUSION: Aneurysmal bone cysts of the pelvis and sacrum are usually aggressive lesions associated with substantial bone destruction, pathological fractures, and local recurrence. Current management recommendations include preoperative selective arterial embolization, excision-curettage, and bone-grafting.

Biomechanical analysis of prophylactic fixation for middle third humeral impending pathologic fractures.

For determination of the most biomechanically desirable construction for prophylactic fixation of impending central 1/3 humeral fractures, 24 matched pairs of fresh frozen skeletonized human cadaveric humeri were divided randomly into four groups. Group 1 compared intact humeri with matched humeri that had a 50% hemicylindrical cortical central 1/3 defect to show reproducible failure at the defect with significant reduction in strength. Groups 2 through 4 compared prophylactic fixation of the defect combined with cementation and dynamic compression plating, Rush rodding, or locked intramedullary nailing. Each specimen was tested in external rotation torsion to failure by fracture. In Group 1, test specimens with defects failed with significantly lower rotation to failure, peak torque, stiffness, and total energy absorbed to failure. In Groups 2 through 4, intramedullary nailing provided statistically significantly better total energy absorbed to failure and stiffness than did dynamic compression plating. The proximally and distally locked intramedullary nail seems to have biomechanical advantages in the prophylactic stabilization of an impending pathologic fracture of the central 1/3 of the humerus. These biomechanical findings must be considered in light of the clinical context when a means of fixation is selected.

Metatarsal lengthening: case report and review of literature.

Shortening of one or more metatarsals may be a cause of metatarsalgia and painful toe deformity. Usually, symptoms are limited and may be successfully addressed with nonoperative treatment. Rarely, operation indicated. This report reviews the surgical techniques, results, and complications. These operations include osteotomy and one-stage distraction with bone grafting, osteotomy and one-stage distraction without bone grafting, osteotomy with gradual distraction and bone grafting, and osteotomy with gradual distraction without bone grafting.

The effect of priming with vecuronium and rocuronium on young and elderly patients.

UNLABELLED: The priming principle consists of administering a subparalyzing dose of nondepolarizing neuromuscular blocking drug 3-6 min before giving a second dose for tracheal intubation. This study was performed to observe the effects of priming doses of vecuronium and rocuronium on pulmonary function tests and muscular weaknesses in young (25-35 yr of age) and elderly (65-73 yr of age) patients. Ten young and 10 elderly patients were each placed in vecuronium and rocuronium groups. Oxygen saturation and train-of-four (TOF) ratio were determined, and pulmonary function tests were performed. Then 20% of the 95% effective dose (ED95) of the muscle relaxants was given intravenously. All tests were performed again 4 min after vecuronium and 3 min after rocuronium. Other signs of muscular weaknesses were also recorded. Elderly patients showed more signs of muscle weakness in both groups. The TOF ratio was 0.77 and 0.79 in the elderly rocuronium and vecuronium groups, respectively, and 0.89 and 0.90 in the young rocuronium and vecuronium groups, respectively. Dynamic spirometry revealed decreases in forced expiratory volume in 1 s and forced vital capacity in both groups, and no significant changes in peak expiratory flow rate. The expiratory reserve volume was reduced more in the elderly groups. Oxygen saturation decreased in both groups. We conclude that oxygen saturation, pulmonary function, and muscle strength decrease more in the elderly than in their younger counterparts from priming doses of vecuronium or rocuronium. IMPLICATIONS: The priming principle consists of giving a subparalyzing dose of muscle relaxant 3-6 min before giving a second dose for tracheal intubation. We found that priming doses of vecuronium and rocuronium produced greater decreases in oxygen saturation and pulmonary function in the elderly (aged 65-73 yr) than their younger (aged 25-35 yr) counterparts. Priming may not be a safe approach in elderly patients.

Spinal column deformity and instability after lumbar or thoracolumbar laminectomy for intraspinal tumors in children and young adults.

STUDY DESIGN: A retrospective study about the occurrence of spinal column deformity or instability after multilevel lumbar or thoracolumbar total laminectomy for removal of benign intraspinal tumors in children and young adults. OBJECTIVES: To analyze the long-term clinical and radiographic outcome of these patients, and to specify factors that affect the occurrence of postlaminectomy spinal column deformity and instability. SUMMARY OF BACKGROUND DATA: Spinal column deformity is not uncommon after multilevel cervical or thoracic laminectomies for removal of intraspinal tumors in children. Its incidence in the lumbar and thoracolumbar spine reportedly is low. METHODS: Thirty-six consecutive patients (23 male, 13 female) underwent multilevel lumbar or thoracolumbar total laminectomy for removal of benign intraspinal tumors from 1966 to 1989. Twelve patients were aged 17 years or younger ("children and adolescents"; mean age, 11 years), and 24 were aged 18-30 years ("young adults"; mean age, 24 years). All patients had preoperative, immediate postoperative, and follow-up clinical and radiographic examinations. RESULTS: At a mean follow-up period of 14 years (range, 4-28 years), six patients (16.6%) had spinal deformity (lordosis or thoracolumbar kyphosis associated with scoliosis), and four (11%) had spondylolisthesis. Spinal column deformity occurred in 33% of children and adolescents and in 8% of young adults. Spondylolisthesis occurred in 16.6% of children and adolescents and in 8% of young adults. Three patients had fusion for spinal column deformity. Pain was present in eight patients, and other neurologic signs and symptoms were found in 18. There was an increased incidence of postoperative spinal deformity in patients who had more than two laminae removed (P < 0.01) or a facetectomy performed at the time of the initial operation (P < 0.05). There was no association between the occurrence of the deformity and sex, neurologic condition after laminectomy, or length of follow-up period. CONCLUSIONS: Spinal deformity or instability after multilevel lumbar or thoracolumbar total laminectomy is not uncommon in children and adolescents. Limiting laminae removal and facet destruction may decrease this incidence. Fusion may be required to correct post-laminectomy deformity and to stabilize the spine.