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Biomedical subjects

V Tolo

Publications and source records attributed to V Tolo.

11 recordsLinked to original sources
PubMed2001

Increased body weight and decreased radial cross-sectional dimensions in girls with forearm fractures.

A large number of children sustain fractures after relatively minor trauma and several investigators have associated these fractures to a deficient accumulation of bone during growth. This study was conducted to better characterize the skeletal phenotype associated with low-energy impact fractures of the forearm in girls. The densities of cancellous, cortical, and integral bone and the cross-sectional area were measured in the radius of 100 healthy white girls (aged 4-15 years) using computed tomography (CT); 50 girls had never fractured and 50 girls had sustained a forearm fracture within the previous month. Fractured and nonfractured groups were matched for age, height, weight, and Tanner stage of sexual development. Compared with controls, girls with fractures had, on average, 8% smaller cross-sectional area at the distal radius (1.82 +/- 0.50 cm2 vs. 1.97 +/- 0.42 cm2; p < 0.0001) but similar cancellous, integral, and cortical bone densities. Neither radial length nor the amount of fat or muscle at the midshaft of the radius differed between girls with and without fractures. Both study subjects and matched controls were overweight. Although mean height was at the 50th percentile, mean weight was at the 90th percentile for age-adjusted normal values. Girls who sustain forearm fractures after minor trauma have small cross-sectional dimensions of the radius and tend to be overweight. The smaller cross-sectional area confers a biomechanical disadvantage that, coupled with the greater body weight, increases the vulnerability to fracture after a fall.

Absorptiometry, Photon↗
PubMed1998

Orthopedics.

Explore the source record for details and available documents.

Child↗
PubMed1997

Retroviral vector-mediated transfer of an antisense cyclin G1 construct inhibits osteosarcoma tumor growth in nude mice.

Metastatic osteosarcoma is a potential target for gene therapy, because conventional therapies are only palliative and metastatic disease is invariably fatal. Overexpression of the cyclin G1 (CYCG1) gene is frequently observed in human osteosarcoma cells, and its continued expression is found to be essential for their survival. Previously, we reported that down-regulation of cyclin G1 protein expression induced cytostatic and cytocidal effects in human MG-63 osteosarcoma cells (Skotzko et al., Cancer Research, 1995). Here, we extend these findings in a tumorigenic MNNG/HOS cell line and report on the effective inhibition of tumor growth in vivo by an antisense cyclin G1 retroviral vector when delivered as concentrated high titer vector supernatants directly into rapidly growing subcutaneous tumors in athymic nude mice. Histologic sections from the antisense cyclin G1 vector-treated tumors showed decreased mitotic indices and increased stroma formation within the residual tumors. Furthermore, in situ analysis of the cell-cycle kinetics of residual tumor cells revealed a decrease in the number of cells in S and G2/M phases of the cell cycle concomittant with an accumulation of cells in the G1 phase. Taken together, these studies demonstrate in vivo efficacy of a high-titer antisense cyclin G1 retroviral vector in an animal model of osteosarcoma.

Animals↗
PubMed1993

G1 expression and multistage dynamics of cyclin A in human osteosarcoma cells.

Cyclin A was initially characterized as a 'mitotic cyclin', believed to function exclusively at the G2-to-M phase transition; however, recent studies have provided compelling evidence that cyclin A additionally functions earlier in the mammalian somatic cell cycle as a putative 'S-phase-promoting factor'. Moreover, numerous inconsistencies have arisen concerning the temporal induction, subcellular localization, subunit configuration, covalent modification and proteolytic destruction of cyclin A, as well as the physiological function of the cyclin A-associated protein kinase complexes. Utilizing precisely synchronized human MG-63 osteosarcoma cells, the present study demonstrates that cyclin A mRNA and protein are clearly expressed in late G1 prior to S-phase entry, as is cyclin A-associated kinase activity and concomitant phosphorylation of the Rb protein. A series of monospecific cyclin A antibodies were generated and utilized to confirm that multiple covalent modifications of cyclin A occur during the course of the cell cycle, and to characterize the subcellular dynamics in additional detail. Pharmacological blockade with mimosine was utilized to further delineate cyclin A expression and to distinguish the temporal induction from the mechanisms of enzyme activation. Subcellular fractionation and immunocytochemical staining localized nascent cyclin A to the cytoplasm, and revealed a distinct translocation to the nucleus during the G1-to-S phase transition. The results of these studies support a multistage model of cyclin A metabolism and enzyme activation.

Amino Acid Sequence↗
PubMed1992

Peripheral congenital arteriovenous fistulae: observe, operate, or obturate?

In 1976, we presented our experience in the surgical management of patients with peripheral congenital arteriovenous fistulae (CAVF). This report updates our experience and specifically describes subsequent experience with intraarterial embolization therapy. Twenty-six infants and children with CAVFs have been treated at Children's Hospital of Los Angeles from 1966 to 1990. The majority of lesions were lower extremity (12), followed by upper extremity (8), shoulder girdle (3), and thorax/neck (3). Seventeen patients had lesions in multiple locations. All patients under 1 year of age had upper extremity lesions, all in the 5- to 10-year age group had lower extremity lesions, and all over 15 years of age at presentation required amputation. Twelve patients had initial embolization therapy and 12 had surgery. Seven of eight patients followed after embolization have improved. Embolization is not effective in large or ulcerated lesions. All patients with embolization alone have residual disease and three of eight have discrepancy in extremity length. Surgery has a 50% complication rate and 7 of 10 followed surgery patients have residual disease. Radiologic catheter techniques and embolization provide a valuable alternative therapy for CAVFs and should be used as the primary form of treatment in most cases.

Adolescent↗
PubMed1989

Electrophysiological recordings during spinal surgery.

Experience with electrophysiological monitoring during surgery of the spinal vertebrae and spinal cord is reviewed. The cerebral somatosensory evoked potential (CSEP) is used to monitor spinal cord conductivity during mechanical manipulation of the vertebrae, most commonly during correction of the curvature of the spine. Abnormal CSEPs were recorded in 11 out of approximately 700 cases of scoliosis surgery. During percutaneous cordotomy, intracord evoked and spontaneous potentials are recorded in order to identify the cord structure. Experiment models are also discussed.

Brain↗
PubMed1988

Spinal cord monitoring during posterior spinal instrumentation and fusion.

Two hundred seventy-five consecutive patients who were treated by posterior spinal instrumentation and fusion with iliac crest bone graft were intraoperatively monitored using cortical somatosensory-evoked potentials without a planned wake-up test. The monitoring was performed using a TECA TE-4 system that included an electromyograph, a nerve stimulator, and a digital averager. Intraoperatively, six patients (2%) demonstrated significant changes in evoked potentials, consisting of either marked increase in latency or a loss of wave form during instrumentation of the spine. The instrumentation was removed immediately and the evoked potentials returned to base-line tracing within 15-30 minutes in all six cases. Five patients who had instruments refitted to maintain a lesser amount of correction had no subsequent change in the evoked potentials. One patient had spinal fusion without instrumentation. Postoperatively, all patients are neurologically normal.

Adult↗
PubMed1981

The use of shortened periods of rigid postoperative immobilization in the surgical treatment of idiopathic scoliosis.

Seventy-eight consecutive patients with idiopathic scoliosis treated by Harrington instrumentation and spine fusion were allowed to walk shortly after operation, first in an underarm plaster cast for ten weeks and then in a canvas-front, hard-back Rohadur or Lexan brace until all external support was discontinued six months after operation. Sixty-four patients were followed for two years or more. Single thoracic curves, comprising almost half of the series, had an average final correction of 48 per cent, while all curves had an average final correction of 44 per cent. The average total loss of correction was 8 degrees, with approximately equal amounts lost in the first and second three months after operation. The incidence of pseudarthrosis was 1.5 per cent and the complications were minor. This series demonstrated that, for cooperative patients with idiopathic scoliosis of less than 90 degrees, the operative procedure and postoperative immobilization described can be expected to result in solid fusion without excessive loss of initial correction, pleasing cosmetic results, and less inconvenience to the patient because of decreased time in a plaster cast and early ambulation.

Adolescent↗
PubMedDate not supplied

The effects of fixed and articulated ankle-foot orthoses on gait patterns in subjects with cerebral palsy.

Twenty-one subjects with spastic diplegic cerebral palsy were studied to quantify the effects of fixed and articulated ankle-foot orthoses (AFOs) on gait and delineate criteria for their use. Children underwent gait analysis under three conditions, fixed AFOs (FAFOs), articulated AFOs (AAFOs), and shoes alone. Greater dorsiflexion occurred at initial contact with both FAFOs and AAFOs than shoes alone. Dorsiflexion at terminal stance was greatest in AAFOs. Plantarflexor power generation at preswing was preserved in AAFOs. No differences were found in knee position during stance. Knee-extensor strength was positively related to knee extension during stance. No relationships were found between dorsiflexion range of motion, calf spasticity and strength, and peak dorsiflexion during stance. AAFOs are appropriate for subjects with varying degrees of calf spasticity, as long as adequate passive range of motion is available. These findings can be applied primarily to children who do not have a preexisting tendency to crouch.

Adolescent↗
PubMedDate not supplied

Chondromyxoid fibroma of the fibula.

A 3 1/2-year-old girl presented with a lytic lesion in the diametaphyseal region of the right fibula. In addition to plain roentgenography, radiological evaluation consisted of bone scintigraphy and computed tomography. The radiological features suggested a benign lesion. Pathological examination revealed a chondromyxoid fibroma.

Bone Neoplasms↗